Definition: secrete products into ducts which empty into body cavities, lumen of hollow organs, or onto body surface; include sweat, oil, mucous, salivary, and digestive glands
Exocrine glands
Definition: most secret products (hormones) into bloodstream; include pituitary, pineal, thyroid, parathyroid, and adrenal glands; also include other tissues that secrete hormones as a second function
Endocrine glands
Definition: secreted by endocrine glands and associated tissues; mediator molecules that are usually carried throughout the body by circulating blood; control body activities; exert their effects by binding specific receptors on or in their "target" cells; some are also neurotransmitters
Hormones
What are the three types of hormonal interactions?
1) Permissive effect
2) Synergistic effect
3) Antagonistic effect
Definition: a type of hormonal interaction where a second hormone strengthens the effects of the first one
Permissive effect
Definition: a type of hormonal interaction where two hormones act together to produce a certain effect; sum of the two together has greater effect than sum of each alone
Synergistic effect
Definition: a type of hormonal interaction where two hormones have opposite effects; one may block effects of the other
Antagonistic effects
What are the two master endocrine glands, since their hormones control other endocrine glands?
1) Hypothalamus
2) Pituitary glands
Which one synthesizes at least nine different hormones and controls secretions from the pituitary gland?
Hypothalamus
Which gland produces releasing hormones that stimulates other glands and tissues to release their hormones?
Anterior pituitary gland
Name the 5 types of cells associated with the anterior pituitary gland.
1) Somatotrophs
2) Thyrotrophs
3) Gonadotrophs
4) Lactotrophs
5) Corticotrophs
Which gland does not synthesize hormones but instead consists of axon terminals of hypothalamic neurons that release two neurotransmitters (oxytocin and antidiuretic hormone) that enter blood and function as hormones?
Posterior pituitary gland
Name two examples of anterior pituitary hormones.
1) Follicle stimulating hormone (FSH)
2) Luteinizing hormone (LH)
Which anterior pituitary hormone initiates the formation of follicles within the ovary, stimulates follicle cells to secrete estrogen, and stimulates sperm production in testes?
Follicle stimulating hormone (FSH)
Which anterior pituitary hormone:
- in females, stimulates: secretion of estrogen, ovulation of secondary oocyte from ovary, formation of corpus luteum, and secretion of progesterone
- in males, stimulates: interstitial cells to secrete testosterone?
Luteinizing hormone (LH)
Name 4 posterior pituitary hormones.
1) Oxytocin
2) Antidiuretic Hormone (ADH)
3) T3 and T4 thyroid hormones
4) Epinephrine and norepinephrine
Which posterior pituitary hormone:
- during delivery: enhances uterine smooth muscle contraction in response to stretch on cervix by baby's head (positive feedback)
- after delivery: stimulates milk ejection and uterine contractions that prevent hemorrhage and restore uterus to original size?
Oxytocin
Which posterior pituitary hormone is also known as vasopressin; functions: decreases urine production and sweating and increases blood pressure (BP)?
Antidiuretic hormone
Which posterior pituitary hormones are released from the thyroid gland, major regulators of metabolic rate, and is also responsible for synthesis of protein, breakdown of fats?
T3 and T4 thyroid hormones
Which posterior pituitary hormones are released from thyroid gland, major regulators of metabolic rate, and is also responsible for synthesis of protein, breakdown of fats, and use of glucose for ATP production?
T3 and T4.
Which posterior pituitary glands are released from the adrenal medulla, effects mimic effects of sympathetic nervous system, and augment fight or flight response?
Epinephrine and norepinephrine
Name the three hormones of the adrenal cortex.
1) Mineralocorticoids
2) Glucocorticoids
3) Gonadocorticoids
Definition: a hormone of the adrenal cortex that is mostly aldosterone; increases reabsorption of Na + and Cl -, bicarbonate and water; and promotes excretion of K + and H +
Mineralocorticoids
Definition: a hormone of the adrenal cortex that is mostly cortisol; helps regulate metabolism; aids in stress resistance by providing nutrients for ATP synthesis; raises blood pressure via vasoconstriction; and reduces anti-inflammatory effects
Glucocorticoids
Definition: a hormone of the adrenal cortex that is mostly androgens (small amount of male hormone produced); insignificant in males; may contribute to sex drive in females; and converted to estrogen in postmenopausal females
Gonadocorticoids
What hormone is released from the pineal gland, involved in regulation of circadian rhythms, and causes sleepiness in darkness?
Melatonin
Name the two ways to regulate calcium blood levels.
1) Calcitonin
2) Parathyroid hormone
Describe the calcitonin regulation of calcium blood levels.
High blood calcium level stimulates calcitonin (CT) release from thyroid gland, which lowers blood calcium level (calcitonin increases uptake of calcium and phosphates for bone building)
Low blood calcium level stimulates parathyroid hormone (PTH) release from parathyroid gland, which raises blood calcium level
Describe the parathyroid hormone regulation of calcium blood levels.
1) Low blood calcium level stimulates parathyroid hormone (PTH) release from parathyroid gland, which raises blood calcium level.
2) PTH enhances bone resorption releasing calcium and phosphates into blood
3) PTH also has actions in kidneys: slows loss of calcium and stimulates synthesis of calcitriol, which increases absorption of calcium in GI tract
4) PTH has opposite function of calcitonin
Which gland has both endocrine and exocrine gland cells?
Pancreas
What percentage of cells in pancreas are arranged in clusters called acini and produce pancreatic juice containing digestive enzymes?
99%
What do the other 1% make up?
The islets of Langerhans composed of 4 types of endocrine cells
What are the 4 types of endocrine cells?
1) Alpha cells
2) Beta cells
3) Delta cells
4) F cells
What type of endocrine cell produces glucagon?
Alpha cell
What type of endocrine cell produces insulin?
Beta cell
What type of endocrine cell produces somatostatin?
Delta cell
What type of endocrine cell produces pancreatic polypeptide?
F cell
Name the two ways to regulate blood glucose levels.
1) Insulin
2) Glucagon
Describe the insulin regulation of blood glucose levels.
High blood glucose stimulates release of insulin from pancreatic beta cells in the islets of Langerhans, which lowers blood glucose
Describe the glucagon regulation of blood glucose levels.
Low blood glucose stimulates release of glucagon from pancreatic alpha cells in the islets of Langerhans, which raises blood glucose
Do insulin and glucagon have the opposite effects of one another?
Yes
Name the three functions of blood.
1) Transportation of:
- Oxygen from lungs to cells; carbon dioxide from cells to lungs for exhalation; nutrients from GI tract to cells; metabolic wastes and heat from cells to lungs, kidneys, and skin for elimination; hormones from endocrine glands to cells
2) Regulation of:
- pH; body temperature; and water balance
3) Protection from:
- Disease via white blood cells (WBCs) and antibodies; excessive blood loss by clotting
What is the normal pH range for blood?
7.35-7.45
In males and females, what is the average amount of volume of blood in the human body?
- In average adult men, 5 to 6 liters
- In average adult women, 4 to 5 liters
Blood accounts for how much of extracellular fluid?
20% of extracellular fluid
Name the two main components of blood and how much each makes up of blood.
1) Blood plasma - makes up 55% of blood
2) Formed elements (cells and fragments) - makes up 45% of blood
Name the different components of blood plasma.
Blood plasma is 91% water, 7% proteins, and the other 1.5% is other solutes
Name the different components of the formed elements.
Formed elements (cells and fragments) is 99% red blood cells (erythrocytes) and less than 1% is white blood cells (leukocytes) and platelets (thrombocytes)
Definition: process of blood cell formation; in adults, only occurs in red marrow located in spongy bone
Hemopoiesis (hematopoiesis)
Definition: globin protein with 4 iron-containing heme pigments attached (each heme pigment can combine reversibly with an oxygen molecule)
Hemoglobin
Where is hemoglobin found?
Found in erythrocytes (red blood cells)
What does hemoglobin transport?
Transports oxygen, carbon dioxide, and nitric oxide in blood
What is the general function of erythrocytes?
Transport oxygen, carbon dioxide, and nitric oxide bound to hemoglobin
What is the general function of leukocytes?
To combat invading pathogens by phagocytosis or immune responses
What is the general function of thrombocytes?
To stop blood loss from damaged blood vessels by forming platelet plug
Definition: sequence of events that stop bleeding in a quick and localized fashion when blood vessels are damaged
Hemostasis
What does hemostasis prevent?
A hemorrhage (loss of a large amount of blood)
What are the methods utilized in hemostasis?
1) Vascular spasm
2) Platelet plug formation
3) Blood clotting (coagulation via formation of fibrin threads)
How many ABO blood types are there? List and describe them.
There are 4 ABO blood types:
1) blood type A: displays only antigen A; have an anti-B antibody
2) blood type B: displays only antigen B; have an anti-A antibody
3) blood type AB: displays both antigens A & B; have neither antibody
4) blood type O: displays neither antigen; have both anti-A and anti-B antibodies
Definition: genetic defect in hemoglobin molecule that displays incomplete dominance inheritance
Sickle-cell disease (anemia)
Describe a person with two sickle-cell genes (2 dominant alleles).
- Has severe anemia
- At very oxygen levels, RBC is deformed due to abnormal hemoglobin
- Has sickle-cell disease
Describe a person with only one sickle-cell gene (1 dominant and 1 recessive allele).
- Has only minor problems with anemia
- Is also a carrier that can pass gene to offspring
- Has increased resistance to malaria
- Has sickle-cell trait
Describe a person with two recessive alleles for sickle-cell disease.
- Produces normal hemoglobin
Name the 5 functions of the lymphatic system.
1) Draining excess interstitial fluid and plasma proteins from tissue spaces
2) Transporting dietary lipids and vitamins from GI tract to the blood
3) Carrying out immune responses
4) Nonspecific resistance to disease
5) Specific resistance to disease
Elaborate on carrying out immune responses.
- Recognizes microbes or abnormal cells and responds by killing them directly or secreting antibodies that cause their destruction
Explain nonspecific resistance to disease.
Provides immediate protection against a wide variety of pathogens and foreign substances; lacks specific responses to specific invaders; uses external mechanical (skin) and chemical barriers (mucus) and internal nonspecific defenses (antimicrobial proteins; natural killer cells and phagocytes; inflammation and fever)
Explain specific resistance to disease.
Provides immunity against specific foreign material or organisms including bacteria, viruses, toxins, and allergens; defense mechanisms involve "specificity" (ability to recognize self and non-self), and "memory" so second encounter produces an even more vigorous response; cell-mediated specific immunity involves direct attack by T cells (lymphocytes); antibody-mediated specific immunity involves response by B cells (lymphocytes) that develop into antibody-secreting plasma cells
Name 4 various substances associated with immune responses.
1) Antigens
2) Haptens
3) Cytokines
4) Antibodies
Definition: substances that are recognized as foreign and provoke an immune response; have immunogenicity (ability to provoke immune response) and reactivity (to antibodies or cell that provoked it)
Antigens
Definition: smaller substances that have reactivity but lack immunogenicity so can't provoke an immune response
Haptens
Definition: small protein hormones that are secreted by lymphocytes and antigen-presenting cells and re involved in immune responses
Cytokines
Definition: substances that are secreted by plasma cells and circulate in blood and lymph where they find, bind, and attack antigens
Antibodies
Name the six actions of antibodies.
1) Produced by plasma cells that develop from B cells (lymphocytes)
2) Neutralizes antigen by blocking effects of toxins or preventing its attachment to body cells
3) Immobilizes bacteria by attacking cilia or flagella
4) Agglutinates and precipitates antigens by cross-linking them
5) Complement activation
6) Enhances phagocytosis
Name the different areas of the four heart chambers.
2 atria (superior chambers) and 2 ventricles (inferior chambers)
What do the four heart valves do?
Open and close in response to pressure changes as heart chambers contract and relax and help to ensure one-way blood flow by opening to let blood flow through and then closing to prevent backflow
What do the atrioventricular (AV) valves consist of?
- Tricuspid valve (between right atrium and right ventricles) and bicuspid valve (mitral) (between left atrium and left ventricle)
What do the semilunar valves consist of?
Pulmonary valve (between right ventricle and pulmonary trunk) and aortic valve (between left ventricle and aorta)
Which chamber of the heart receives blood from superior and inferior vena cavae (from body), and coronary sinus (from heart) and delivers blood to right ventricle through tricuspid valve?
Right atrium
Which chamber of the heart receives blood from right atrium and pumps blood through pulmonary valve to lungs and back to heart; has thinner muscle wall than left ventricle
Right ventricle
Which chamber of the heart receives blood from lungs through 4 pulmonary veins and delivers blood to the left ventricle through bicuspid valve?
Left atrium
Which chamber of the heart receives blood from left atrium and pumps blood through aortic valve to body systems and back to heart, as well as to heart itself; has much thicker muscle wall than right ventricle
Left ventricle
Definition: a heart valve disorder that involves narrowing of valve associated with failure of valve to open fully
Stenosis
Definition: a heart valve disorder that involves narrowing of mitral valve associated with failure of valve to open fully
Mitral stenosis
Definition: a heart valve disorder that involves narrowing of aortic valve associated with failure of valve to open fully
Aortic stenosis
Definition: a heart valve disorder that involves failure of valve to close completely, which allows backflow of blood
Insufficiency or incompetence
Definition: a heart valve disorder that involves failure of mitral valve to close completely, which allows backflow of blood from left ventricle into left atrium
Mitral insufficiency
Definition: a heart valve disorder that involves failure of aortic semilunar valve to close completely, which allows backflow of blood from aorta into left ventricle
Aortic insufficiency
What is the most common cause of a heart murmur?
A heart valve disorder
Definition: abnormal sound consisting of clicking, rushing, or gurgling heard before, between, during, or after normal heart sounds
A heart murmur
Name the two types of circulation.
1) Systemic circulation
2) Pulmonary circulation
Describe systemic circulation.
Left side of the heart is pumped for systemic circulation: pumps oxygenated blood to tissues, drops off oxygen and nutrients and picks up carbon dioxide and wastes, and returns deoxygenated blood back to the heart
Learn the path and events of systemic circulation.
Left atrium receives bright, red newly oxygenated blood returning from pulmonary circulation (lungs) -> bicuspid (mitral) valve -> left ventricle -> aortic semilunar valve -> aorta -> systemic arteries -> systemic arterioles -> systemic capillaries in tissues -> drops off oxygen and nutrients and picks up carbon dioxide and wastes -> returns deoxygenated blood to venules -> veins -> vena cavae -> right atrium
Describe pulmonary circulation.
Right side of the heart is pumped for pulmonary circulation: pumps deoxygenated blood to lungs, picks up oxygen and drops off carbon dioxide for exhalation, and returns oxygenated blood back to heart
Learn the path and events of pulmonary circulation.
Right atrium receives all dark, red deoxygenated blood returning from systemic circulation -> tricuspid valve -> right ventricle -> pulmonary semilunar valve -> pulmonary trunk -> right and left pulmonary arteries -> pulmonary arterioles -> pulmonary capillaries in right and left lungs -> drops off carbon dioxide and picks up oxygen -> returns to oxygenated blood to pulmonary venules -> pulmonary veins -> left atrium
Definition: network of specialized self-excitable cardiac muscle (CM) fibers that provide an inherent source of rhythmical electrical activity responsible for the heart's continuous beating
Autorhythmic fibers
What are the functions of the autorhythmic fibers?
- 'Pacemaker' to set rhythm of electrical excitation that causes contraction of the heart
- 'Conduction system' to provide path for each cycle of cardiac excitation to progress through the heart
Where does cardiac excitation normally begin?
In the sinoatrial (SA) node located in right atrial wall
What is the pacemaker of the heart?
SA node; SA node cells have a pacemaker potential; do not have stable resting potential, but repeatedly depolarize to threshold spontaneously
What is the sequence of action potential propagation through conduction system of heart?
Sinoatrial (SA) node -> atrioventricular (AV) node in interatrial septum -> AV bundle (bundle of HIS) in interventricular septum -> right and left bundle branches toward apex of heart -> Purkinje fibers -> upward to remainder of ventricular myocardium -> then ventricles contract, pushing blood upward through semilunar valves
Definition: composite record of action potentials produced by all cardiac muscle fibers during each heart beat
Electrocardiogram (ECG or EKG)
How many waves does an EKG consist of? List them.
Three waves:
1) P wave
2) QRS complex
3) T wave
Definition: the wave of the EKG that represents atrial depolarization
P wave
Definition: the wave of the EKG that represents rapid ventricular depolarization
QRS complex
Definition: the wave of the EKG that indicates ventricular repolarization
T wave
Does the EKG also measure time spans (intervals or segments) between waves?
Yes; P-Q interval, Q-T interval, S-T segment
In an EKG, what can provide clues to abnormalities?
The size of waves and length of intervals and segments
Do atria and ventricles contract and relax at the same time or at different times?
At different times
Definition: contraction phase caused by depolarization
Systole
Definition: relaxation phase caused by repolarization
Diastole
Definition: atria are contracting (ventricles are in diastole; relaxed); pressure in atria increases; atrioventricular valves become pushed open
Atrial systole
Definition: ventricles are contracting (atria are in diastole; relaxed); pressure in ventricles increases; atrioventricular valves become pushed shut; semilunar valves become pushed open
Ventricular systole
Definition: atria are relaxed
Atrial diastole
Definition: ventricles are relaxed
Ventricular diastole
Describe congestive heart failure.
Heart is a failing pump; one side of the heart often starts to fail before the other side
What happens if the left ventricle of the heart fails?
Blood backs up in the lungs and causes pulmonary edema
What happens if the right ventricle of the heart fails?
Blood backs up in systemic veins, results in peripheral edema
Definition: blood vessels within walls of large vessels that supply them with oxygen and nutrients
Vasa vasorum
Definition: vein with thin endothelial wall that has no smooth muscle to alter diameter
Vascular (venous) sinus
Definition: union of branches from two or more blood vessels, lymphatic vessels, or nerves supplying same body region that provides alternate route for blood to or from tissue or organ if blood flow is blocked elsewhere
Anastomosis
Definition: wider, more winding capillaries with unusually large fenestrations
Sinusoids
How is vascular smooth muscle is innervated?
By sympathetic neurons of autonomic nervous system, which regulate blood vessel diameter
Definition: narrowing of blood vessel lumen via contraction of vascular smooth muscle or by vasospasm; stimulated by increase in sympathetic activation
Vasoconstriction
Definition: increase in lumen diameter by relaxation of smooth muscle; may be due to decrease in sympathetic stimulation
Vasodilation
List the three general functions of blood vessels.
1) Arteries carry blood away from the heart
2) Veins carry blood toward the heart
3) Capillaries deliver blood from arterioles to venules
Definition: largest diameter arteries; also called conducting arteries because they conduct blood from heart to muscular arteries
Elastic arteries
Definition: medium-sized arteries; also called distributing arteries because they distribute blood to various parts of body
Muscular arteries
Definition: very small arteries that deliver blood to capillaries; also called resistance vessels because contraction and relaxation of smooth muscle in arteriole walls can change their diameter and significantly affect blood pressure
Arterioles
Definition: microscopic vessels that connect arterioles to venules; also called exchange vessels because main function is exchange of nutrients and wastes between blood and tissues through interstitial fluid
Capillaries
Definition: very small veins formed when several capillaries unite; collect blood from capillaries and drain into veins
Venules
Definition: Formed when venules merge; much thinner and have larger lumen than arteries; many, especially those in limbs, have valves to prevent backflow of blood as it slows on its return to heart
Veins
Definition: hydrostatic pressure exerted by blood on arterial walls and is produced by the left ventricle in systole and the pressure remaining in the arteries when the left ventricle is in diastole; measured with sphygmomanometer (blood pressure cuff) and stethoscope
Blood pressure (BP)
Definition: traveling pressure wave created by alternating expansion and recoil of elastic arteries after each left ventricular systole
Pulse
Definition: various sounds that are heard while taking blood pressure
Korotkoff sounds
Describe the first sound.
Corresponds to systolic blood pressure; heard when pressure cuff deflated enough for artery to open; sudden faintness of sounds as cuff deflated more: corresponds to diastolic blood pressure
How many sounds are there during each cardiac cycle? How many are loud enough to hear through a stethoscope?
There are 4 heart sounds during each cardiac cycle, but only first 2 (S1 and S2) are loud enough to hear through a stethoscope.
Definition: lubb; caused by blood turbulence associated with closure of AV valves after ventricular systole begins
First sound (S1)
Definition: dupp; caused by blood turbulence associated with closure of semilunar (SL) valves at beginning of ventricular diastole
Second sound (S2)
What is the normal value for resting blood pressure (BP) in a young adult male?
About 120/80 mmHg
What is the normal value for resting heart rate (pulse rate)?
70-80 beats/min
What is the normal value for resting stroke volume?
70 mL
What is the normal value for resting cardiac output (CO)?
5.25 L/min
What are the cardiovascular effects of epinephrine and norepinephrine?
Increase heart rate and contractility, blood pressure, and blood flow to muscle during exercise
What is a myocardial infarction commonly called?
A heart attack
Definition: death of heart tissue distal to an area of completely obstructed blood flow in a coronary artery; dead tissue is replaced with noncontractile scar tissue
Myocardial infarction
List the methods of treatment for a myocardial infarction.
1) Injection of a thrombolytic (clot-dissolving) agent and an anticoagulant
2) Coronary angioplasty
3) Coronary artery bypass graft
Name the two functional divisions of the respiratory system.
1) Conducting portion
2) Respiratory portion
Which functional division includes nose, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles?
Conducting portion
What are the functions of the conducting portion of the respiratory system?
Warm air, filter air, moisten air, and conduct it into the lungs
Which functional division includes respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli?
Respiratory portion
What is the function of the respiratory portion of the respiratory system?
Gas exchange between air and blood
Definition: closes off larynx during swallowing to route food and liquids into the esophagus and prevent them from getting into the airways
Epiglottis
Definition: function in holding breath against pressure in thoracic cavity
Ventricular folds (false vocal cords)
Definition: function in producing sounds (voice)
Vocal folds (true vocal cords)
Definition: serous membrane layer that covers lungs
Visceral pleura
Definition: serous membrane layer that lines pleural cavity
Parietal pleura
Definition: inflammation of the pleural membrane
Pleurisy (pleuritis)
Definition: excess accumulation of fluid in the pleural space due to persistent inflammation
Pleural effusion
Definition: filling of the pleural cavity with air due to an injury to the chest wall that allows air to enter the intrapleural space
Pneumothorax
Definition: substance in alveolar fluid that lowers its surface tension to reduce the tendency of alveoli to collapse
Surfactant
Definition: wandering phagocytes that remove dust and debris in alveolar spaces
Alveolar macrophages
Definition: inhalation of medication in form of a fine mist to treat respiratory disorders
Nebulization
What is the most important muscle of inhalation?
Diaphragm
Define: dome-shaped muscle that flattens as it contracts and increases volume of chest cavity, reducing pressure, so air moves into lungs
Diaphragm
What also assists in inhalation?
External intercostals
Definition: involved in deep, forceful inhalations, but contribute little to normal quiet inhalation
Sternocleidomastoids and scalenes
Does normal quiet exhalation involve muscle contraction?
No
Why is normal quiet exhalation a passive process?
Because of the elastic recoil of stretched chest wall and lungs as diaphragm relaxes
Definition: involved in forceful exhalations
Abdominals and internal intercostals
What is measured by a spirometer?
Lung respiratory volumes
Definition: volume of one breath while at rest; normally about 500 mL of air
Tidal volume
Definition: additional air that is inhaled by taking a very deep breath
Inspiratory reserve volume
Definition: additional air that is exhaled as forcibly as possible after inhaling normally
Expiratory reserve volume
Definition: air that remains in the lungs after maximal forcible exhalation; cannot be measured by spirometry
Residual volume
Definition: sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume
Vital capacity
Definition: sum of vital capacity and residual volume
Total lung capacity
How many steps of respiration are there? List them.
1) Pulmonary ventilation
2) External respiration
3) Internal respiration
Definition: inhalation and exhalation of air
Pulmonary ventilation
Definition: diffusion of oxygen from lung alveoli to blood in pulmonary capillaries and diffusion of carbon dioxide in the opposite direction
External respiration
Definition: movement of oxygen from systemic capillaries into tissue cells and transfer of carbon dioxide in the opposite direction
Internal respiration
Definition: located in the medulla oblongata and controls the basic rhythm of respiration
Medullary rhythmicity area
Definition: located in the lower pons and sends stimulatory impulses to inspiratory area to prolong inhalation
Apneustic area
Definition: located in the upper pons and transmits inhibitory impulses to the inspiratory area to shorten the duration of inhalation so the lungs won't overfill with air
Pneumotaxic area
Definition: chewing
Mastication
Definition: swallowing
Deglutition
Definition: take in of food, liquids, or drugs by mouth
Ingestion
Definition: mechanical and chemical breakdown of food into small molecules
Digestion
Definition: passage of dietary molecules from stomach and intestines into blood and lymph
Absorption
Definition: progressive, wavelike contractions of the muscularis that push substances (food) onward; begins in esophagus; also occurs in stomach, small intestines, and large intestines
Peristalsis
Definition: gentle, rippling, peristaltic movements in the stomach
Mixing waves
Definition: breakdown of large lipid globules into a suspension of small, uniform droplets via bile salts
Emulsification
Definition: soft, flexible mass of ground up food mixed with saliva that is formed in the mouth and swallowed
Bolus
Definition: soupy liquid composed of macerated food mixed with gastric gland secretions that is formed in the stomach
Chyme
Definition: clusters of glandular epithelial cells of the pancreas that secrete pancreatic juice, containing many digestive enzymes, into small intestine; account for 99% of pancreatic cells
Acini
Definition: lymphatic vessels in villi of the intestines that absorb lipids from digested food
Lacteals
Definition: elimination of feces
defecation
List the digestive system structures and organs.
Salivary glands, teeth, tongue, esophagus, stomach, small intestine, large intestine, liver, gall bladder, and pancreas
Name the three salivary glands.
1) Parotid
2) Submandibular
3) Sublingual
What are the functional components in saliva?
- Salivary amylase to begin breakdown of starch
- Lingual lipase to breakdown lipids
- Water for dissolving foods
- Mucus for lubricating food
- Lysozyme to kill bacteria
- Ions that activate amylase and buffer acids in food
What binds, grinds, and chews food?
Teeth
What organ tastes and forms bolus (chewed food)?
Tongue
Definition: transports food into the stomach
Esophagus
Definition: mechanical digestion (mixing waves) and chemical digestion by gastric gland secretions; contains gastric glands
Stomach
Definition: folds that allow stomach to stretch
Rugae
Name the three types of gastric glands.
1) Parietal cells
2) Chief cells
3) G cells
Definition: gastric gland cells that produce intrinsic factor (needed for absorption of vitamin B12) and hydrochloric acid (needed for breakdown of proteins)
Parietal cells
Definition: gastric gland cells that secrete pepsinogen and gastric lipase
Chief cells
Definition: enteroendocrine cells in the stomach that secrete gastrin
G cells
Definition: site of most digestion and absorption of nutrients
Small intestine
How does digestion occur?
It occurs via pancreatic and intestinal juices in lumen and brush-border enzymes in plasma membrane of microvilli
Definition: phagocytic cells in deepest part of intestinal glands that secrete lysozyme
Paneth cells
What does long length provide?
It provides large surface area for digestion and absorption.
What are the three structures that further increase surface area?
1) Circular folds
2) Villi
3) Microvilli
Do circular folds stretch like rugae of the stomach?
No
Name the three regions of the small intestine.
1) Duodenum
2) Jejunum
3) Ileum
What intensifies ileal peristalsis and forces chyme in ileum into cecum?
Gastroileal reflex
What are the functions of the large intestine?
Completion of absorption, production of certain B and K vitamins, formation and expulsion of feces
Name the four different regions of the large intestine.
1) Ascending
2) Transverse
3) Descending
4) Sigmoid colon
Definition: distention of haustra (pouches) causes walls to contract and squeeze contents into next haustrum
Haustral churning
Definition: mass peristalsis, initiated by food in stomach, that drives contents of colon into rectum
Gastrocolic reflex
Definition: last 8 inches of GI tract
Rectum
Definition: contains internal (involuntary) and external (voluntary) sphincters; opens to expel feces
Anus
Definition: located on inferior aspect of liver and stores and release bile
Gall Bladder
What are the functions of the liver?
- Carbohydrate, lipid, and protein metabolism
- Nutrient storage
- Detoxifies certain substances
- Removes certain wastes
- Synthesizes cholesterol and lipoproteins
- Stores iron, copper, and fat soluble vitamins
- Produces bile
- Kupffer cells phagocytize bacteria and worn out cells
Definition: produce hormones including insulin and glucagon; 1% of pancreas (endocrine)
Islets of Langerhans
Definition: produce pancreatic juice containing several digestive enzymes; 99% of pancreas (exocrine)
Acini (clusters)
What is the composition of pancreatic juice?
Contains water, enzymes, and sodium bicarbonate
List the five digestive enzymes.
1) Pancreatic amylase
2) Pancreatic lipase
3) Proteases
4) Ribonuclease
5) Deoxyribonuclease
Definition: the digestive enzyme that breaks down starch
Pancreatic amylase
Definition: the digestive enzyme that breaks down lipids
Pancreatic lipase
Definition: the digestive enzyme that breaks down peptides (protein)
Proteases
Definition: the digestive enzymes that digest nucleic acids
Ribonuclease and deoxyribonuclease
In the nutrients lab, what detects absorbic acid?
Indophenol
In the nutrients lab, what detects albumin (protein)?
Benedict's agent
In the nutrients lab, what detects starch (polysaccharide carbohydrate)?
Lugol's iodine solution
In the nutrients lab, what detects corn oil (lipid)?
Sudan red
Definition: sum of all chemical reactions in the body
Metabolism
What are the two phases of metabolism?
Catabolism and anabolism
Definition: the phase of metabolism that involves chemical reactions that break down complex organic molecules into simpler ones; decomposition reactions; exergonic reactions (produce more energy than they consume)
Catabolism
Definition: the phase of metabolism that involves chemical reactions that combine simpler molecules to build more complex ones; are synthesis reactions; endergonic reactions (consume more energy than they produce)
Anabolism
What is the molecule that participates most often in energy exchanges?
ATP
What type of reactions does ATP couple together?
Catabolic reactions and anabolic reactions
Where is most ATP produced?
In the mitochondria
How is most ATP produced?
By aerobic respiration
What does ATP contain that store potential energy that can be used to drive chemical reactions in the body?
High energy phosphate bonds
Definition: a reaction that involves removal of electrons from a molecule; result in decrease in potential energy; are called dehydrogenation reactions because most involve removal of H atoms
Oxidation reactions
Definition: a reaction that involves addition of electrons to a molecule; result in increase in potential energy; two hydrogens are added as H+ and H-
Reduction reactions
Are oxidation and reduction reactions always coupled?
Yes, as one substance is oxidized, another is reduced
Definition: complete breakdown (oxidation) of glucose to generate 36 or 38 ATP for energy
Cellular respiration
What does cellular respiration include?
Includes:
- anaerobic phase (glycolysis) and aerobic phase (Kreb cycle and electron transport chain)
- a transitional step between glycolysis and Kreb cycle: acetyl coA formation
Definition: occurs in the cytosol and does not require oxygen (anaerobic); first step in the glucose catabolism; begins with one glucose and ends with 3 pyruvic acids; produces 2 NADH + H+ and 2 net ATP
Glycolysis
Definition: occurs in mitochondria and requires oxygen (aerobic); begins with 2 pyruvic acids and ends with 2 acetyl coAs; transitional step that produces 2 NADH + H+ and 2 carbon dioxides, but no ATP
Acetyl coA formation
Definition: occurs in mitochondria and requires oxygen (aerobic); makes 2 turns of the cycle; each turn begins by combining acetyl coA with oxaloacetic acid and ends with oxaloacetic acid required for next turn; produces 6 NADH + H+, 2 FADH(2), 2 ATP, and 4 carbon dioxides
Krebs cycle
Describe the electron transport chain (Notecard 1).
- Occurs in mitochondria and requires oxygen
- Has 3 clusters of electron carriers that transfer electrons and act as proton pumps that expel H+ from the mitochondrial matrix
Electron transport chain (Notecard 2).
- Series of redox reactions remove electrons and hydrogen from NADH and FADH(2) produced in previous steps: pass electrons along electron carriers and pump H+ across inner membrane
- Has 2 mobile electron carriers: coenzyme Q and cytochrome c
- coenzyme Q: shuttles electrons from pump 1 to pump 2
- cytochrome c: shuttles electrons from pump 2 to pump 3
Electron transport (Notecard 3).
- Also has ATP synthase with H+ channel that allows H+ to flow back across the inner membrane, creating a proton motive force that is used to generate ATP
- Oxygen is the final electron acceptor in the electron transport chain
- Produces 32 or 34 ATP
Definition: contain most dietary lipids, which they carry to adipose tissue storage
Chylomicrons
Definition: primarily contain endogenous lipids synthesized in liver, which they transport to adipocytes for storage
Very low-density lipoproteins (VLDLs)
Definition: transport 75% of the total cholesterol in blood to cells throughout the body, and contribute to formation of fatty plaques that increase risk of coronary artery disease when levels are high
Low-density lipoproteins (LDLs)
Definition: remove excess cholesterol from body cells and carry it to the liver for elimination, and prevent buildup of cholesterol in blood so high levels are associated with low risk of coronary artery disease
High-density lipoproteins (HDLs)
Definition: splitting of triglycerides into glycerol and fatty acids; lipid catabolism; catalyzed by lipases; inhibited by insulin
Lipolysis
Definition: synthesis of lipids from sources such as glucose and amino acids; lipid anabolism; occurs when individual consumes more calories than needed for ATP synthesis; stimulated by insulin
Lipogenesis
Definition: usually used to measure the body's metabolic rate and express energy content of food
Calorie
Definition: form of energy that can be measured in temperature and expressed in calories
Heat
Definition: energy storage form of carbohydrates; in liver and skeletal muscle
Glycogen
Definition: energy storage form of lipids; in adipose tissue and yellow bone marrow
Triglycerides
Can proteins and amino acids be stored?
No
Definition: rate at which metabolic reactions use energy in quiet resting, fasting state
Basal metabolic rate
Definition: main regulators of basal metabolic rate
Thyroid hormones T3 and T4
Definition: ingested nutrients are entering bloodstream and glucose is readily available for ATP production
Absorptive state
What are the 2 metabolic hallmarks?
1) Oxidation of glucose for ATP synthesis
2) Storage of excess fuel molecules for between-meal use
Is insulin a dominant hormonal regulator?
Yes
Definition: absorption of nutrients from GI tract is complete so energy needs must be met by fuels already in body
Postabsorptive state
In the postabsorptive state, what do the metabolic reactions include?
- Providing glucose by breakdown of glycogen or new synthesis
- Switching from glucose to alternate fuels for ATP synthesis
In the postabsorptive state, what do the hormone regulators include?
- Glucagons
- Epinephrine
- Norepinephrine
Definition: contain nephrons that filter blood and form urine containing wastes to be excreted
Kidneys
Definition: transport urine from kidneys to bladder
Ureters
Definition: stores urine until elimination from body
Urinary bladder
Definition: transports urine from bladder to outside of body for elimination; in males, is also common pathway for semen to be ejaculated
Urethra
What is the functional units of the kidneys?
Nephrons
What are the two parts of a nephron?
1) Renal corpuscle
2) Renal tubule
Definition: where blood is filtered to form filtrate
Renal corpuscle
Definition: where filtered filtrate passes into and water and solute reabsorption and secretion takes place to form urine
Renal tubule
What are the two compartments of the renal corpuscle?
1) Glomerulus
2) Bowman's capsule
Definition: capillary network
Glomerulus
Definition: surrounds glomerulus
Bowman's capsule
What are the three main sections of the renal tubule?
1) Proximal convoluted tubule
2) Loop of Henle
3) Distal convoluted tubule
Definition: site of most water and solute reabsorption
Proximal convoluted tubule
What are the two parts of the loop of Henle?
1) Descending limb
2) Ascending limb
Definition: the part of the loop of Henle that is the additional site of obligatory water reabsorption
Descending limb
Definition: the part of the loop of Henle that has little or no water reabsorption, ions only
Ascending limb
Definition: major cite of calcium reabsorption stimulated by parathyroid hormone drains into collecting duct
Distal convoluted tubule
List the path of filtered blood through a nephron to the collecting duct.
Glomerulus -> proximal convoluted tubule -> loop of Henle -> distal convoluted tubule -> collecting duct
List the path of urine flow from the collecting ducts through elimination from the body.
Collecting ducts -> papillary ducts -> minor calyces -> major calyces -> renal pelvis -> ureters -> urinary bladder -> urethra -> discharge from the body
Why is reabsorption of sodium by renal tubules particularly important?
Because more sodium passes glomerular filters than any other substance except water
Why does solute reabsorption drive water reabsorption?
Because all water is reabsorbed by osmosis
Definition: water is reabsorbed together with solutes in tubular fluid because it is 'obliged' to follow solutes when they are reabsorbed; occurs in proximal convoluted tubule and descending limb of loop of Henle; accounts for 90% of water reabsorption
Obligatory water reabsorption
Definition: adapts to need and is regulated by antidiuretic hormone (ADH); occurs in primarily in collecting ducts; accounts for final 10% of water reabsorption
Facultative water reabsorption
What does homeostasis of body fluid volume largely depend on?
The kidney's ability to regulate amount of water loss in urine
When is a large volume of dilute urine produced?
When fluid intake is high
When is a small volume of concentrated urine produced?
When fluid intake is low or fluid loss is great (dehydration or blood loss)
What hormone controls whether dilute or concentrated urine is produced?
Antidiuretic hormone (ADH)
What happens if ADH is absent?
Very dilute urine is formed
What happens if there are high levels of ADH present?
It stimulates more water reabsorption into blood so concentrated urine is formed
Definition: substance that dissociates into cations and anions in water and conducts electrical currents; includes acids, bases, and salts
Electrolyte
Definition: substance dissolved in water that does not dissociate into ions so does not conduct electricity
Nonelectrolyte
What type of electrolyte lights up a light bulb brightly?
Strong electrolyte
What type of electrolyte lights up a light bulb dimly?
Weak electrolyte
What type of electrolyte does not light up a light bulb?
Nonelectrolyte
What are the functions of electrolytes?
- Help maintain acid-base balance
- Control osmosis between fluid compartments
- Conduct electric current
- Serve as cofactors for enzymatic activity
How do buffers prevent rapid, drastic changes in pH?
By turning strong acids and bases into weak ones
What are the three types of buffer systems?
1) Phosphate buffer system
2) Carbonic acid-bicarbonate buffer system
3) Protein buffer system
Definition: an acid-base imbalance where there is a decrease in blood pH due to drop in HCO3- in systemic arterial blood
Metabolic acidosis
Definition: an acid-base imbalance where there is an increase in blood pH due to rise HCO3- in systemic arterial blood
Metabolic alkalosis
Definition: an acid-base imbalance where there is a decrease in pH due to abnormally high P(CO2) in systemic arterial blood
Respiratory acidosis
Definition: an acid-base imbalance where there is an increase in pH due to abnormally low P(CO2) in systemic arterial blood
Respiratory alkalosis
Definition: male gonads consisting of a pair of oval glands that produce male gametes (sperm) and secrete hormones, including testosterone; contain seminiferous tubules where sperm are made
Testes (testicles)
Definition: supporting sac that holds testes
Scrotum
Definition: site where sperm mature and acquire motility and ability to fertilize ovum
Epididymis
Definition: stores viable sperm up to several months and delivers sperm from epididymis toward urethra via peristalsis; sperm that are not ejaculated are reabsorbed
Ductus deferens (vas deferens)
Definition: pass through prostate and terminate in prostatic urethra, where they eject sperm and seminal vesicle secretions just before ejaculation
Ejaculatory ducts
Definition: forceful propulsion of semen from urethra to exterior
Ejaculation
Definition: shared terminal duct of urinary and reproductive systems; ends at external urethral orfice
Urethra
What are the three parts to the urethra?
1) Prostatic
2) Membranous
3) Spongy (penile)
Definition: include seminal vesicles, prostate, and bulbourethral glands, and secrete most of liquid portion of semen
Accessory sex glands
Definition: secrete alkaline, viscous fluid that contains fructose, prostaglandins, and clotting proteins and accounts for 60% of volume of semen
Seminal vesicles
Definition: secretes milky, slightly acidic fluid that contains citric acid, proteolytic enzymes, acid phosphatase, and constitutes 25% of volume of semen
Prostate gland
Definition: secrete alkaline fluid into urethra that protects passing sperm by neutralizing acids from urine, and secrete mucous that lubricates urethra and end of penis to minimize sperm-damage during ejaculation
Bulbourethral glands (Cowper's glands)
Definition: consists of erectile tissue and urethra and provides passageway for excretion of urine and ejaculation of semen
Penis
Definition: enlarged region of corpus spongiosum at distal end of penis that contains external urethral orfice; covered by loose-fitting prepuce (foreskin) if penis is not circumcised
Glans penis
Definition: surgical procedure in which some or all of prepuce is removed
Circumcision
Definition: female gonads, which produce gametes and hormones, including estrogen, progesterone, inhibin, and relaxin
Ovaries
Definition: secondary oocytes that develop into mature ova after fertilization
Gametes
Definition: extend laterally from uterus and provide route for sperm to reach ovum and transport secondary oocytes and fertilized ovum to uterus (from ovaries)
Uterine tubes (Fallopian tubes)
Definition: part of pathway for sperm from vagina to uterine tubes; site of implantation of fertilized ovum, fetal development, and labor; when implantation does not occur, source of menstrual flow
Uterus
Definition: inferior narrow part of uterus that opens into vagina
Cervix
Definition: long fibromuscular canal lined with mucous membrane that extends from exterior to cervix; receives penis during sexual intercourse; outlet for menstrual flow; passageway for childbirth
Vagina
Definition: external genitals of female
Vulva
Definition: 2 longitudinal folds of skin covered with pubic hair that are homologous to scrotum
Labia majora
Definition: 2 smaller folds medial to labia majora
Labia minora
Definition: small, cylindrical mass of erectile tissue and nerves; homologous to glans penis; also has prepuce
Clitoris
Definition: reproductive organs that produce gametes (sperm or oocytes) and secrete sex hormones
Gonads
What are the gonads in males?
Testes that produce and release haploid cells called sperm; also produce testosterone
What are the gonads in females?
Ovaries that produce and release haploid cells called secondary oocytes; also produce estrogen, progesterone, relaxin, and inhibin
All the cells in the human body, except gametes, have how many pairs of chromosomes?
23 pairs, with one member of each homologous pair inherited from each parent; represents the diploid number (2n), total of 46 chromosomes
Reproductive cell division in gonads produces gametes that have how many chromosomes?
Half as many as somatic cells; they have haploid number (n): total of 23 chromosomes; joining of gamete nuclei during fertilization produces normal diploid number (2n) (23 chromosomes from each parent: total of 46)
Definition: reproductive cell division
Meiosis
Meiosis occurs in two stages of division. What are they called?
1) Meiosis I
2) Meiosis II
How does meiosis I begin and end?
Begins with diploid parent cell and ends with 2 haploid daughter cells
How does meiosis II begin and end?
2 haploid cells formed from meiosis I divide and produce 4 haploid gametes in males or 1 gamete in females that are genetically different from original diploid parent cell
Definition: two events that occur in prophase of meiosis I but not in prophase of mitosis or meiosis II
Synapsis and genetic crossing-over
Definition: 2 sister chromatids of each pair of homologous chromosomes pair off forming a tetrad
Synapsis
Definition: results in genetic recombination and produces daughter cells that are not like each other or parent cells
Crossing-over of genes between nonsister chromatids
Where are sperm and testosterone produced?
In the seminiferous tubules
Definition: process of sperm production
Spermatogenesis
Definition: maturation of spermatids into sperm
Spermiogenesis
List the stages of maturation of spermatogenic cells in males.
Spermatagonia -> primary spermatocytes -> secondary spermocytes -> spermatids -> spermatozoa (sperm)
List the stages of follicular development in females.
Primordial follicle -> primary follicle -> secondary follice -> Graafian follicle
What are the functions of testosterone?
- Prenatal development of male reproductive ducts and descent of testes
- Development of male sexual characteristics at puberty
- Development of sexual function and involvement in spermatogenesis
- Stimulation of anabolism, especially protein synthesis, for increased bone and muscle mass
What do the ovaries in females do?
Produce gametes and hormones
Definition: secondary oocytes that develop into mature ova after fertilization
Gametes
Definition: include estrogen, progesterone, inhibin, and relaxin
Hormones
Definition: formation of gametes in ovaries
Oogenesis
Definition: the hormone that is secreted by anterior pituitary and initiates growth of ovarian follicles (one matures each month) and secretion of estrogen by growing follicles
Follicle-stimulating hormone (FSH)
Definition: expulsion of secondary oocyte
Ovulation
What happens to the oocyte if fertilization doesn't occur?
The oocyte degenerates.
What happens if sperm is present in the uterine tube and and one penetrates an oocyte?
Meiosis II resumes and oocyte splits into 2 haploid (n) cells of unequal size: ovum (larger cell) and second polar body (smaller cell)
Definition: nuclei of sperm and ovum unite, forming diploid (2n) zygote
Fertilization
What are the functions of the corpus luteum?
- Contains remnants of a mature Graffian follicle after ovulation
- Produces progesterone, estrogens, inhibin, and relaxin until it degenerates
- Degenerates into fibrous scar tissue called corpus albicans
What are the functions of the luteinizing hormone (LH) in the female reproductive system?
- Secreted by anterior pituitary
- Stimulates further follicular development and secretion of estrogens
- Triggers ovulation followed by formation of corpus luteum
- Stimulates corpus luteum to secrete estrogens, progesterone, relaxin, and inhibin
What are the functions of estrogen in the female reproductive system?
-Secreted by follicular cells
- Functions to promote development and maintenance of female reproductive structures and breasts, and secondary sex characteristics
- Works with progesterone to prepare and maintain the endometrium for a fertilized ovum
Definition: includes events of ovarian and uterine cycles and changing hormone levels
Female reproductive cycle
List the four stages of the female reproductive cycle.
1) Menstrual
2) Pre-ovulatory
3) Ovulation
4) Postovulatory
Definition: use estrogens and progestins to prevent pregnancy
Hormonal methods
Definition: block sperm from gaining access to the uterine cavity
Barrier methods
Definition: kill sperm
Spermicides
Definition: renders person incapable of reproduction
Surgical sterilization
Definition: cutting and tying or removal of portion of each ductus deferens via small incision in scrotum in males
Vasectomy
Definition: Cutting and tying or removal of portion of each uterine tube in females
Tubal ligation
Definition: use of physiological cues of reproductive cycle to abstain from intercourse on days when pregnancy likely
Periodic abstinence
Definition: premature expulsion of embryo or fetus, usually before 20th week
Abortion
Definition: diploid nucleus formed when haploid pronuclei of sperm (male) and ovum (female) fuse and produce cell with 46 chromosomes (23 from each pronucleus); undergoes divisions to become blastocyst that is implanted in uterus
Zygote
Definition: weeks 1 through 8; involves development of all major organs, although their functions are minimal; folic acid deficiency during this time produces neural tube defects
Embryo
Definition: weeks 9 through birth; involves extensive growth and differentiation of existing tissues and organs, but little formation of new structures
Fetus
Definition: process by which fetus is expelled from uterus through vagina
Labor
Definition: giving birth
Parturition
What is the normal position of giving birth for the baby?
Head first
Definition: fetal buttocks or lower limbs first; may be delivered surgically through C-section
Breech presentation
Describe the placenta.
- Site of exchange of nutrients and wastes between the mother and fetus
- Connected to fetus by umbilical cord that contains umbilical vein and umbilical arteries
- Produces hormones required to sustain pregnancy
- Expelled after delivery of the baby and is then referred to as the "afterbirth"
Definition: an opening where some blood passes from right atrium to left atrium in a fetus; this is because fetal lungs are not functional
Foramen ovale
How does mot blood bypass the fetal lungs and enter systemic circulation?
By crossing from the pulmonary trunk into the aorta through ductus arteriosis
How many branches does the umbilical vein divide into?
Two: one branch joins hepatic portal vein, but most blood flows into 2nd branch called ductus venosus, which drains into inferior vena cava (delivers oxygenated blood with nutrients from placenta to fetus)
Definition: return deoxygenated blood with wastes from fetus to placenta
2 umbilical arteries
Definition: abnormal condition of pregnancy characterized by sudden hypertension, high protein concentration in urine, and generalized edema
Preeclampsia
Definition: when condition in last notecard is also associated with convulsions and coma
Eclampsia
Somatic cells have many pairs of homologous chromosomes?
23; 22 pairs are same in males and females (autosomes) and 1 pair is different in males and females (sex chromosomes)
What are the sex chromosomes for a male and a female?
- Male: XY
- Female: XX
Definition: actual genetic makeup; actual alleles that code for each trait
Genotype
Definition: how genetic makeup is expressed in the body; outward appearance of each trait in the body
Phenotype
Definition: chart that shows possible combinations of gametes from 2 parents
Punnett square
Definition: trait that is expressed by dominant allele; expressed when 2 dominant alleles or 1 dominant and 1 recessive allele present
Dominant trait
Definition: allele that dominates and masks another allele
Dominant allele (D)
Definition: trait that is controlled by recessive allele; expressed when two recessive alleles are present
Recessive trait
Definition: allele that is masked by presence of dominant allele
Recessive allele (d)
Definition: same alleles (DD or dd) on homologous chromosomes
Homozygous
Definition: different alleles (Dd) on homologous chromosomes
Heterozygous
Definition: heterozygous person who carries recessive gene but doesn't express it
Carrier
Definition: neither allele in pair is dominant over other, so heterozygote has intermediate phenotype between homozygous dominant and homozygous recessive phenotypes; example: sickle-cell trait
Incomplete dominance
Definition: although person only inherits 2 alleles, more than 2 alternative alleles may exist; example: blood type
Multiple-allele inheritance
Definition: usually carried on X chromosomes
Sex-linked traits
Describe sex-linked traits for females.
For recessive traits, female may have dominant normal allele to mask recessive allele for disorder, so doesn't express trait but is a carrier
Describe male-linked traits for males.
Males only have one X chromosome, so if allele is present, it will be expressed
What are some examples of recessive X-linked traits?
Red-green color blindness and hemophilia
Definition: chromosomes that aren't homologous break and exchange sections
Translocation
Definition: error in cell division that results in abnormal number of chromosomes
nondisjunction
Definition: usually caused by trisomy of chromosome 21 (nondisjunction during cell division that results in extra copy of chromosome 21)
Down syndrome
Definition: genetic disorders that are sex-linked inheritance on X chromosome
Hemophilia and red-green color blindness
Describe sickle cell disease.
- Displays incomplete dominance
- Homozygous dominant: Normal hemoglobin
- Homozygous recessive: Sickle cell disease and severe anemia
- Heterozygous: Minor problems with anemia because half hemoglobin is normal, and half is not