Nerve impulses leading to the skeletal muscle carry information to direct movement. The nerve fibers sending these signals will most likely belong to which division of the nervous system? Nerve impulses leading to the skeletal muscle carry information to direct movement. The nerve fibers sending these signals will most likely belong to which division of the nervous system?
a. sensory (afferent) division
b. somatic nervous system
c. sympathetic division
d. parasympathetic division
Which of the following types of glial cells monitors the health of neurons, and can transform into a special type of macrophage to protect endangered neurons?
C. ependymal cells
The concentration neurotransmitters in the fluid of the synaptic
cleft must be tightly regulated for neurons to function properly.
Which of the following cells is most responsible for aiding in this
A. satellite cells
C. Schwann cells
Axon diameter and degree of myelination determine nerve impulse
At which point of the illustrated action potential would voltage-gated Na+ channels be mostly open but voltage-gated K+ channels be mostly closed?
You discover that a new chemical compound interacts with K+ voltage-dependent channels. What would be the effect on a neuron if the chemical came into contact with the axonal membrane?
A. The cell would die.
B. The cell would be unable to depolarize.
C. The neuron would be unable to repolarize.
D. The cell would be unable to generate a resting potential.
bc K+ is used to repolarize the membrane after Na+ rushes into the membrane.
Local anesthetics block voltage-gated Na+ channels, but they do not block mechanically gated ion channels. Sensory receptors for touch (and pressure) respond to physical deformation of the receptors, resulting in the opening of specific mechanically gated ion channels. Why does injection of a local anesthetic into a finger still cause a loss of the sensation of touch from the finger?
A. The local anesthetic prevents Na+ from causing the initial depolarization of this sensory receptor.
B. The local anesthetic prevents any type of repolarization of this sensory receptor.
C. Touch stimulation of this sensory receptor requires that there be a simultaneous opening of voltage-gated Na+ channels and mechanically gated ion channels.
D. Touch stimulation of this sensory receptor will open the mechanically gated ion channels, but action potentials are still not initiated because propagation of an action potential requires the opening of voltage-gated Na+ channels.
bc Propagation (spreading) of an action potential from the cell body to the axon hillock and eventually the axon terminals (synaptic knobs) requires the sequential opening of mechanically and voltage-gated ion channels. When the sequence is interrupted, the message cannot spread to the sensory regions of the central nervous system, causing numbness.
Loss of function in the enzyme acetylcholinesterase would result in which of the following?Loss of function in the enzyme acetylcholinesterase would result in which of the following?
A. stimulation of the production of acetylcholine
B. inability to destroy and remove acetylcholine from the synaptic cleft
C. decrease or reduce the effect of ACh
D. inability to release acetylcholine
Which of the following neurotransmitters inhibits pain and is mimicked by morphine, heroin, and methadone?
A. nitric oxide
The term cerebral dominance designates the hemisphere that is dominant for language.
bc One cerebral hemisphere or the other "dominates" each of the brain's tasks, and the term cerebral dominance designates the hemisphere that is dominant for language. In most people (about 90%), the left hemisphere has greater control over language abilities, math, and logic.
After Joe has a stroke, his doctor asks Joe to touch his right pointer finger to his chin—but Joe is unable to move his right hand. However, when the doctor stimulates Joe's pointer finger with a painful stimulus, Joe's muscles quickly move his hand away from the stimulus. The doctor concludes that ______.
A. the stroke caused damage to Joe's frontal eye field which interfered with his effort to touch his chin
B. the stroke caused damage to Joe's right primary motor cortex
C. the stroke caused damage to Joe's right premotor cortex
D. based on the doctor's observations, none of the listed answers are correct conclusions
A patient reports that she has become completely deaf—she can't hear anything. Thorough tests on her ears indicate that her ears have not been damaged. Additional tests reveal that her deafness has been caused by damage to her ______.
A. primary somatosensory cortex
B. auditory association area
C. somatosensory association cortex
D. None of the listed responses is correct.
At age 79, Mrs. X is diagnosed with a disorder that severely impairs her logical judgment. Medical imaging techniques show that this has been most likely caused by brain damage in a ______.
A. parietal lobe
B. frontal lobe
C. temporal lobe
D. premotor cortex
An individual who could trace a picture of a bicycle with his or her finger but could not recognize it as a bicycle is most likely to have sustained damage to the ________.
A. visual association area
B. primary visual cortex
C. calcarine cortex
D. lateral geniculate body
The area of the cortex that is responsible for sensing a full bladder and the feeling that your lungs will burst when you hold your breath too long is the ________.
A. gustatory cortex
B. olfactory cortex
C. visceral sensory area
D. vestibular cortex
Which brain nucleus is the body's "biological clock"?
A. lentiform nucleus
B. suprachiasmatic nucleus
C. dorsomedial nucleus
D. subthalamic nucleus
Vital centers for the control of heart rate, respiration, and blood pressure are located in the ________.
A. medulla oblongata
Degeneration of the dopamine-releasing neurons of the ________ is the ultimate cause of Parkinson's disease.
A. internal capsule
B. substantia nigra
C. reticular formation
D. red nucleus
Which functional area of the brain is responsible for our level of awareness and alertness?
A. Broca's area
B. frontal eye fields
C. reticular activating system
D. limbic system
bc The reticular activating system is responsive to our sensory input and controls alertness to these sensory inputs and our awareness and responsiveness to our external (and internal) environment.
Emotional state, rehearsal, association, and automatic memory are all factors that affect the transfer of information from short-term memory (STM) to long-term memory (LTM).
Nondeclarative memories preserve the circumstances in which they are learned.
Which type of memory is exemplified by a racing heartbeat upon hearing a rattlesnake nearby?
A. procedural (skills)
C. declarative (fact)
Which of the following is NOT a function of the CSF?
A. nourishment of the brain
B. reduction of brain weight
C. protection from blows
D. initiation of some nerve impulses
__________ is a progressive degenerative disease of the basal nuclei that affects the dopamine-secreting pathways
A. Huntington's disease
B. mad cow disease
C. Parkinson's disease
D. Alzheimer's disease
bc Parkinson's disease results from a degeneration of the dopamine-releasing neurons of the substantia nigra (of the midbrain). As those neurons deteriorate, the dopamine-deprived basal nuclei they target become overactive. Afflicted individuals have a persistent tremor at rest, a forward-bent walking posture and shuffling gait, and a stiff facial expression. They are slow with initiating and executing movement.
Cell bodies of first order sensory neurons are located in ________.
A. sympathetic ganglia
B. the dorsal root ganglia of the spinal cord
C. the ventral root ganglia of the spinal cord
D. the thalamus
An individual accidentally transected (cut across) the spinal cord between T1 and L1. This would result in ________.
A. spinal shock only
Select the true statement regarding first-order neurons.
A. First-order neurons descend with motor commands.
B. First-order neurons originate in the CNS.
C. First-order neurons usually ascend directly to the thalamus.
D. First-order neuron cell bodies reside in a ganglion.
Neural tracts that convey information to the brain concerning temperature and pain would be ________.
A. lateral spinothalamic
B. ventral (anterior) spinothalamic
D. posterior spinothalamic
Second-order neurons of ascending pathways that contribute to sensory perception terminate in the ________.
A. somatosensory cortex
C. spinal cord
We can touch our finger to our nose while our eyes are closed in part because we can sense the position and movement of our joints as well as the length of stretch in our muscles. These sensations create awareness of our body's positioning. The following receptors are most likely responsible for this ability.
A person picks up a heavy suitcase in order to estimate its weight and reflexively drops it. Which of the following receptors has initiated this reflex?
A. tendon organ
B. free nerve ending
C. lamellae corpuscle
D. bulbous corpuscle
Transduction refers to conversion of ________.
A. stimulus energy into energy of a graded potential
B. afferent impulses to efferent impulses
C. receptor energy to stimulus energy
D. presynaptic nerve impulses to postsynaptic nerve impulses
Phasic receptors adapt quickly to a stimulus. For that reason, they are good at detecting changes instead of constantly signaling the CNS.Phasic receptors adapt quickly to a stimu
Phasic receptors adapt rapidly; they are good at detecting changes in stimuli, which is more energetically efficient than constantly sending a signal to the CNS.
__________ do NOT exhibit the property of adaptation
A. Sensory receptors
B. Phasic receptors
C. Tonic receptors
Tonic receptors provide a sustained response with little or no adaptation. Nociceptors and most proprioceptors are tonic receptors because of the protective importance of the information.
Hiccups could occur if there was irritation or damage to the ______
A. dorsal rami of spinal nerves associated with the C3-C5 region of the spinal cord
B. afferent neurons of spinal nerves associated with the C3-C5 region of the spinal cord
C. cutaneous branches of rami associated with the C3-C5 region of the spinal cord
D. motor branches of ventral rami associated with the C3-C5 region of the spinal cord
The ventral rami of spinal nerves contain motor fibers that originate from neuron soma found in the spinal cord. These efferent pathways activate the contraction of skeletal muscle. The phrenic nerve branches from this region and innervates the skeletal muscle of the diaphragm
A patient has lost vision on the left side of both eyes. The patient has likely suffered damage to ________.
A. the retinas of the eyes
B. the right optic tract
C. the optic nerves
D. the optic chiasm
Ralph sustained a leg injury in a bowling accident and had to use crutches. Unfortunately, he never took the time to learn how to use them properly. After two weeks of use, he noticed his fingers were becoming numb. Then he noticed his arms were getting weaker and had a tingling sensation. What could be his problem?
A. Compression of the radial nerve (in the region of the armpit) may cause temporary cessation of nervous transmission, often called "Saturday night paralysis."
B. Compression of the musculocutaneous nerve (in the region of the armpit) may cause temporary cessation of nervous transmission, often called "Saturday night paralysis."
C. Compression of the median nerve (in the region of the armpit) may cause temporary cessation of nervous transmission, often called "Saturday night paralysis."
D. The median nerve is being compressed, making it difficult to pick up small objects, and resulting in the tingling sensations in his fingers.Pulling on the brachial plexus is causing weakness in the muscles of his arms, and may lead to paralysis.
A herniated lumbar disc could interfere with ______.
A. skin sensations from the lateral thigh
B. skin sensations from the medial thigh
C. adduction of the thigh
D.All of the listed responses are correct.
A knee-jerk reflex that is unusually strong may be caused by ______.
A. inhibition of reciprocal inhibition
B. transmission of excitatory signals from the brain to the neurons that form the femoral nerve
C. suppression of muscle spindle activity in the lower limb
D. enhancement of activity in the antagonistic muscles
A patient has an injury of the spine and is now suffering from a loss of motor function in his right arm. However, he still has normal sensory function in the arm. Based on this information it is likely that the patient has nervous tissue damage located at ________.
A. the dorsal rootlets located at one of the thoracic vertebra
B. the dorsal root located at one or more of the cervical vertebra
C. spinal nerves of the cervical vertebra
D. the ventral root located at one or more of the cervical vertebra
Dorsal and ventral rami are similar in that they both contain sensory and motor fibers.
Which reflex is triggered when a stranger suddenly grasps your arm?
A. stretch reflex
B. plantar reflex
C. tendon reflex
D. crossed-extensor reflex
Once a preganglionic axon reaches a trunk ganglion, one of three things can happen to the axon. Which of the following is NOT one of these three things?
A. The axon can pass through the trunk ganglion and emerge from the sympathetic trunk without synapsing.
B. The axon can ascend or descend the sympathetic trunk to synapse in another trunk ganglion.
C. The axon can course back into the spinal cord to synapse with preganglionic neurons in a different spinal segment.
D. The axon can synapse with a ganglionic neuron in the same trunk ganglion.
Preganglionic axons do not pass back into the spinal cord.
Where would you NOT find autonomic ganglia?
A. paired, beside spinal cord
B. within wall of organ served or close to organ
C. unpaired, anterior to spinal cord
D. within spinal cord
The rami communicantes are associated only with the sympathetic division of the ANS.
You are designing a drug to reduce heart rate. Which receptor would you target?Y
A. muscarinic receptors
B. Î²1 adrenergic receptors
C. nicotinic receptors
D. (1 adrenergic receptors
Muscarinic receptors inhibit cardiac cells.
Drugs called beta-blockers ________
A. decrease heart rate and blood pressure
B. have widespread sympathetic effects
C. are potent antidepressants
D. increase a dangerously low heart rate
Which of the following is an effect of norepinephrine binding to beta 2 adrenergic receptors?
C. an increase in heart rate
The binding of norepinephrine to the beta 2 adrenergic receptors in blood vessels causes vasodilation.
Which of the following outcome criteria show that a patient is effectively coping with a stressful problem?
A. Regular heart rate, regular blood pressure, cold and sweaty skin, dilated pupils
B. Regular heart rate, warm and dry skin, dilated pupils, unlabored breathing
C. Increased heart rate, labored breathing, cold and sweaty skin, dilated pupils
D. Increased heart rate, labored breathing, warm and dry skin, constricted or normal pupils
E. Regular heart beat, unlabored breathing, warm and dry skin, constricted or normal pupils
Which of the following best demonstrates an example of cooperation of the parasympathetic and sympathetic nervous systems?
A. Parasympathetic stimulation causes vasodilation of blood vessels in the penis, leading to erection; sympathetic stimulation then causes ejaculation.
B. Parasympathetic stimulation causes copious sweating; sympathetic stimulation causes epidermal pores to dilate.
C. Sympathetic stimulation causes vasodilation of blood vessels in the penis, leading to erection; parasympathetic stimulation then causes ejaculation.
D. Sympathetic stimulation causes vasodilation of blood vessels in the clitoris, leading to erection; parasympathetic stimulation then causes reflex contractions of the vagina.
The best example of cooperative autonomic effects is seen in controls of the external genitalia. Parasympathetic stimulation causes vasodilation of blood vessels in the external genitalia, and is responsible for erection of the male penis or female clitoris during sexual excitement. Sympathetic stimulation then causes the ejaculation of semen by the penis or reflex contractions of the vagina during an orgasm.
Erection (vasodilation) of the penis or clitoris ________.
A. is primarily under parasympathetic control
B. is primarily under sympathetic control
C. is the result of coordinated activation by both sympathetic and parasympathetic input
D. depends very little on autonomic activation
A mugger steals your wallet causing all of the following to happen EXCEPT ________.
A. Increased metabolic rate
B. increased glucose uptake to the liver from blood
C. increased rate and force of heartbeat
D. inability to read close-up print
All visceral organs receive dual innervation from both the sympathetic and parasympathetic divisions of the ANS.
Control of temperature, endocrine activity, and thirst are functions associated with the ________.
Nutrients are delivered and waste products are carried away from the cells of the posterior segment of the eye by blood vessels. However, the cells in the cornea and lens (in the anterior segment) are avascular. Which is the best explanation for how these cells are maintained?
A. The aqueous humor is continuously replenished and flows from the ciliary process to drain in the scleral venous sinus.
B. The metabolic activity of these cells is very low. They produce little waste and need few nutrients.
C. The nutrients and waste products of the anterior segment diffuse into and through the vitreous humor of the posterior segment.
D. These cells, like the cells of the corneal layer of the integument are not living cells.
Light passes through the entire thickness of the neural layer of the retina to excite the photoreceptors.
As the ciliary muscle relaxes, the suspensory ligaments tighten and stretch the lens, allowing for distance vision
Sympathetic innervation relaxes the ciliary body. As the muscle relaxes, it pulls on the suspensory ligaments, which put tension on the lens. This allows images that are farther away to focus on the retina.
During close vision, what actions must the eye take to bring an
object into focus?
A. relax the ciliary body
B. change the curvature of the cornea
C. contract the ciliary body
D. dilate the pupil
Contracting the ciliary body would allow the lens to recoil and bulge, which would enhance focus on close objects.
Which of the following is the best explanation of why it is difficult to discriminate the color of an object at night?
A. Rods contain a single kind of visual pigment.
B. Cones come in three types, each sensitive to different wavelengths of light.
C. The foveae are densely packed with cones.
D. As many as 100 cones may converge on one ganglion cell.
Select the statement below that is not true with regards to the process of light adaptation.
A. Visual acuity is diminished.
B. Rhodopsin is uncoupled from light transduction.
C. Retinal sensitivity decreases.T
D. The activity of rods is reduced by rapid bleaching of rhodopsin
Humans can see several thousand shades of color but have cone photoreceptors that are sensitive to only three (perhaps four) wavelengths of light. What is the best explanation for why we see so many colors?
A. Color perception is dependent on the millions of rods as well as cone photoreceptors.
B. Shades of color are purely psychological and learned by association with age, infants only seeing in black and white.
C. Color perception is achieved by activation of various combinations between the three cone types.
D. Colors are added and enhanced in the primary visual cortex of the brain.
Dark adaptation ________.
A. is much faster than light adaptation
B. results in inhibition of rod function
C. involves accumulation of rhodopsin
D. primarily involves improvement of acuity and color vision
During otitis media, large amounts of fluid or pus may accumulate in the tympanic cavity; the fluid is primarily ______
A. interstitial fluid
C. bacterial fluida
D. hypertonic fluid
Interstitial fluid is the fluid between cells. Pus is a thin, protein-rich fluid that consists of tissue fluid, dead cells, and immune cells found at a sight of inflammation.
Humans can smell as many as 10,000 different odors but have significantly fewer types of olfactory receptors. Which of the following is the best explanation for why humans can distinguish so many smells?
A. Taste receptors that are active at the same time influence the subtlety of what we smell.
B. The sensation of a single, distinct smell is a combination of a variety of chemicals that stimulate different combinations of olfactory receptor cells all at once.
C. The belief that we can smell so many different distinct odors is a psychological process referred to as an uncinate fit or olfactory hallucination.
D. The olfactory pathway travels to location in the brain in which memories are formed and we simply mix this new sensory information with old memories.
Which of the following would be the LEAST likely to be associated with the development of motion sickness
A. driving rapidly over winding roads
B. reading a book while being a passenger in a car
C. having a non-functional vestibular apparatus
D. taking a ride in a Ferris wheel
The vestibular apparatus is important in detecting changes in linear velocity.
Flavor preferences, our likes and dislikes are said to have a "homeostatic value". Which of the following is the best example of this homeostatic value for taste preferences?
A. The temperature, smell and texture of foods will influence its overall taste.
B. Alkaloids are chemical compounds in plants that are frequently toxic "antifeedant" chemicals. Alkaloids are often unpleasantly bitter.
C. Capsaicin is a chemical compound in chili peppers. Nociceptors in the mouth respond to this chemical with the sensation of heat.
D. Monosodium glutamate is a food additive that stimulates umami taste (gustatory) cells.
At rest, when no sound is entering the cochlea, the hair cells send
At rest, the hair cells are slightly active and send a few depolarizing signals.
Transduction of lower frequency sound waves occurs at the __________ of the cochlea.
C. proximal end
The apex is wider and more flexible, which makes it more receptive to lower frequencies.
As sound levels increase in the spiral organ (of Corti), ________.
A. outer hair cells bend the cilia away from the kinocilium
B. outer hair cells stiffen the basilar membrane
C. inner hair cells bend the cilia away from the kinocilium
D. inner hair cells stiffen the basilar membrane
The sensation of loudness or the volume of a sound is detected by ________.
A. high volume sounds can travel all the way the apex of the scala vestibule with enough energy remaining to deflect hair cells
B. faster vibration of the basilar membrane resulting in a higher frequency of hair cell stimulation
C. vibration along a greater length of the basilar membrane, stimulating a greater number of hair cells
D. greater movement of the basilar membrane resulting in greater deflection of the hair cells
Congenital sensorineural deafness most commonly involves damage to ______.
A. the auricles
B. the cochlear hair cells
C. the auditory ossicles
D. All of the listed responses are correct.
The mesenchyme of the ectoderm will eventually form the bony labyrinth of the inner ear. Sound waves distort the cochlear hair cells, resulting in stimulation of the cochlear nerve. Loss of these hairs results in deafness.
A patient has a loss of hearing in only one ear. Which of the following is likely to be a result?
A. The patient will not be able to track objects with the eye on the same side as the hearing loss.
B. The patient will have increased sensitivity to sound in the unaffected ear.
C. The patient will have a loss of balance with dizziness and vertigo.
D. The patient will not be able to localize the origin of sounds.
Dancers will use a technique called "spotting" when they perform spins of the body. By holding their head and eyes on a fixed point in front of them as their body spins they reduce the amount of head spinning and this prevents dizziness. Which of the following is the most likely explanation for why this works?
A. Reducing the inertia of head spin will reduce the flow of endolymph that deflects the hair cells of the crista ampullaris.
B. This helps keep the motions detected by the eyes congruent (aligned) with the motions sensed by the vestibular apparatus.
C. This will help to reduce the lateral flection of the head and will prevent hyper polarization or depolarization of the hair cells in the macula.
D. When the eyes send a static vision of stability to the brain, it is tricked into believing the body is still and therefore dizziness will not occur.
Theoretically, an individual born without a middle ear would be able to hear by bone conduction with a hearing aid.
The benefit of using a second messenger signaling system is rapid speed of communication.
The benefit of second messenger signaling is the amplification that occurs inside of the cells; small amounts of signal create a large response.
Which of the following can act on receptors inside the target cell that directly activate specific genes?
A. growth hormone
Hormones often cause a cell to elicit multiple responses; this is because ________.
A. during protein kinase activation, enzymes phosphorylate many other enzymes
B. the protein kinases are rapidly metabolized into functional amino acids
C. the receptors bind to several hormones at the same time
D. there are thousands of receptors on the cell membrane
Cells that respond to peptide hormones usually do so through a sequence of biochemical reactions involving receptor and kinase activation. In order for cells to respond, it is necessary for first and second messengers to communicate. This is possible because ________
A. hormones alter cellular operations through direct stimulation of a gene
B. G protein acts as the link between first and second messengers
C. peptide hormones are converted by cell membranes enzymes into second messengers
D. the hormone receptor complex moves into the cytoplasm as a unit
Thyroxine is a peptide hormone, but its mechanism is different from other peptide hormones. Which of the following statements is true concerning this difference?
A. It is a stimulant of cellular metabolism and targets all cells.
B. It causes positive feedback.
C. It does not require a second messenger to cause a response.
D. It is very specific in the cell type it targets.
One of the least complicated of the endocrine control systems directly responds to changing blood levels of ions and nutrients. Which of the following describes this mechanism
A. humoral stimulation
B. carbohydrate oxidation
C. protein synthesis
D. catabolic inhibition
Up-regulation involves the loss of receptors and prevents the target cells from overreacting to persistently high hormone levels.
Down-regulation involves the loss of receptors and prevents the target cells from overreacting to persistently high hormone levels.
In circumstances where the body requires prolonged or increased levels of a hormone, the DNA of target cells will specify the synthesis of more receptors on the surface of the cells of the target organ. This is known as ________.
B. a stressor reaction
C. cellular affinity
D. sensitivity increase
Why does antidiuretic hormone help regulate an abnormal increase in solute concentration in the extracellular fluid?
A. It causes secretion of solutes by the kidney, resulting in a decreased solute concentration.
B. It causes reabsorption of water by the kidney, resulting in increased blood water volume and a decreased solute concentration.
C. It causes more sodium secretion by the kidney, resulting in a decreased solute concentration.
D. It causes less sodium reabsorption by the kidney, resulting in a decreased solute concentration.
E. It causes less reabsorption of water by the kidney, resulting in lower solute reabsorption and a decreased solute concentration.
A man has been told that he is NOT synthesizing enough follicle-stimulating hormone (FSH), and for this reason he may be unable to father a child. Choose the correct statement to explain this problem.
A. The man must be producing progesterone, which inhibits the synthesis of FSH.
B. A hormone made in the anterior pituitary cannot influence fertility.
C. FSH stimulates sperm production in the testes.
D, FSH stimulates estrogen secretion by ovarian cells; therefore it is not synthesized by males.
Johanna is significantly shorter than normal for her age. Her doctor recommends treatment with a hormone before her growth plates ossify in her long bones. Which hormone is recommended?J\
B. parathyroid hormone
C. thyroid stimulating hormone
D. growth hormone
As a result of stress the anterior pituitary releases ________, which stimulates release of hormones from the adrenal cortex that retain sodium and water, increase blood sugar, and begin breaking down fats.
A. growth hormone
B. thyroid stimulating hormone
Which letter represents the hormone that promotes a decrease in blood pressure and a loss of sodium and water in urine?
The letter D indicates atrial natriuretic peptide, which is released from the heart when high blood pressure is sensed. It causes more sodium (“natrium”) to be placed in the urine (“uretic”).
Examples of adrenal gland short-term stress responses include immune system suppression and retention of salt and water by the kidneys
Upon landing at the airport in Lagos, Nigeria, Eric feels wide awake even though the local time is 11pm. Which synthetic hormone supplement could he administer to help adjust to the new time zone?
B. growth hormone
Adult onset diabetes, diabetes type 2, can best be described using which of the following concepts?
A. Constantly high blood sugar leads to high insulin release. High levels of insulin cause up-regulation of insulin receptors.
B. Constantly high blood sugar leads to high insulin release. High amounts of insulin lead to down-regulation of insulin receptors.
C. Constantly high blood sugar leads to glucagon release. Glucagon is an antagonist to insulin, leading to a decrease in insulin.
D. Constantly high blood sugar leads to the release of glucagon. Glucagon causes gluconeogenesis, which makes blood sugar higher.
High levels of insulin cause the down-regulation of insulin receptors. Type 2 diabetes is sometimes called insulin insensitivity because of the lack of insulin receptors.
Many hormones synthesized in the gastrointestinal tract are chemically identical to brain neurotransmitters.
With a patient that is administered an injection of erythropoietin (EPO) you would expect to see ________.
A. Increased white blood cell count
B. decreased hematocrit
C. decreased white blood cell count
D. increased hematocrit
With a patient administered an injection of colony stimulating factor (CSF) you would expect to see ________.
A. Increased Red blood cell count
B. increased white blood cell count
C. decreased Red blood cell count
D. decreased white blood cell count
Suppose that an individual injects himself with erythropoietin in order to raise his level of endurance, an act that is usually illegal in competitive sports. Which of the following could result?
A. a lower hematocrit
C. decreased blood viscosity
D. reduced tendency for blood to clot
Erythropoietin causes an increase in release of erythrocytes, which, unless regulated, can induce polycythemia. EPO increases the hematocrit and the red cell mass and can lead to increased viscosity of the blood and an increased tendency to form clots.
Bilirubin is created when red blood cells are recycled. How is it removed from the blood stream?
A. the spleen
B. the liver
C. the kidneys
D. the pancreas
As RBCs are broken down, their hemoglobin is recycled. Bilirubin is a yellow pigment that results from the degradation of the heme groups and is released to the blood. The liver cells pick up the bilirubin and secrete it in bile. Once bile is secreted into the intestine, the bilirubin is converted to urobilinogen and is excreted with the feces.
Which of the following might trigger erythropoiesis?
A. an increased number of RBCs
B. decreased tissue demand for oxygen
C. moving to a lower altitude
D. hypoxia of EPO-producing cells
A lack of intrinsic factor, leading to a deficiency of vitamin B12 and causing an appearance of large pale cells called macrocytes, is characteristic of ________.
B. pernicious anemia
C. sickle-cell anemia
D. aplastic anemia
Positive chemotaxis is a feedback system that signals leukocyte migration into damaged areas.
Which granulated leukocyte is most likely to be active during a bacterial infection?
Neutrophils are active in phagocytizing bacteria.
A person with an extremely high count of neutrophils is likely suffering ________.
C. a viral infection
D. a bacterial infection
Which leukocyte might you expect to find in higher quantities in a person experiencing allergies?
Eosinophils have a role in causing allergies.
What factor stimulates platelet formation?
B. interleukin 2
Platelet formation is stimulated by thrombopoietin.
Which step in hemostasis involves activation of formed elements in the blood?
A. fibrin production
B. vascular spasm
C. platelet plug formation
Platelets are formed elements that are activated by damaged tissue. Platelets for a temporary plug preventing blood loss.
Which of the following represents a difference between extrinsic and intrinsic blood clotting pathways?
A. One leads to the production of prothrombin activator and the other does not.
B. One is triggered by tissue damage, while the other cannot be triggered by tissue damage.
C. One involves calcium ions, while the other does not.
D. One is faster than the other.
The extrinsic pathway is faster than the intrinsic pathway.
What protein involved in coagulation provides the activation for the final step in clotting?
c. prothrombin activator
Thrombin catalyzes fibrinogen into fibrin. This is the final step in coagulation
A man enters the hospital complaining of chest pain. His history includes smoking, a stressful job, a diet heavy in saturated fats, lack of exercise, and high blood pressure. Although he is not suffering from a heart attack, his doctor explains to him that a heart attack is quite possible. What did the chest pain indicate? Why is this man a prime candidate for further complications?
A. Myocardial infarction. If the coronary arteries are occluded (atherosclerosis), the heart muscle could be deprived of oxygen, resulting in a heart attack.
B. Angina pectoris. If the coronary arteries are occluded (atherosclerosis), the heart muscle could be deprived of oxygen, resulting in a heart attack.
C. A heart attack. If the coronary arteries are occluded (atherosclerosis), the heart muscle could be deprived of calcium, resulting in endocarditis.
D. Myocarditis. If the heart continues to become more inflamed, the heart muscle could be deprived of oxygen, resulting in a heart attack.
E. Angina pectoris. If the coronary arteries are occluded (atherosclerosis), the heart muscle could be deprived of calcium, resulting in a heart attack.
If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells, ________.
A. it would be much longer before cardiac cells could respond to a second stimulation
B. contractions would last as long as the refractory period
C. tetanic contractions might occur, which would stop the heart's pumping action
D. pacemaker cells would cease to spontaneously depolarize
Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle.
The order of impulse conduction in the heart, from beginning to end, is __________.T
A. SA node, AV node, bundle of His, bundle branches, and Purkinje fibers
B. SA node, bundle of His, AV node, bundle branches, and Purkinje fibers
C. SA node, bundle branches, AV node, bundle of His, and Purkinje fibers
D. SA node, bundle branches, bundle of His, AV node, and Purkinje fibers
The impulses of the heart originate at the SA node (pacemaker). The impulse is then transmitted to the AV node (atrioventricular node), where the impulse slows down to allow the atria to completely contract and thereby fill the adjacent ventricles. The AV node then transmits the impulse to the bundle of His, which branches into left and right bundle branches. The bundle branches give rise to the Purkinje fibers, which transmit the impulse to the ventricle walls and stimulate ventricular contraction.
Asystole is the total absence of ventricular electrical activity. Would defibrillation be effective in this situation?
A. Defibrillation would be effective: it repolarizes the cardiac cells, allowing the heart to function normally again.
B. Defibrillation would be effective, because it targets the SA node to induce its autorhythmic activity.
C. Defibrillation would be effective, because it resets the heart's electrical activity.
D. Defibrillation would not be effective: it interrupts chaotic electrical activity in the heart, and if there is no electrical activity, then there is nothing to interrupt.
Which of the following is NOT part of the intrinsic conduction system of the heart?
A. atrioventricular (AV) node
B. atrioventricular (AV) valve
C. bundle branches
D. sinoatrial (SA) node