Anatomy & Physiology - Endocrine System
Chemical signals produced in small amounts
List the characteristics that apply to the endocrine system when compared to the nervous system
1. amplitude-modulated signals
2. usually slower response
3. effects usually more generally distributed
Name the intercellular chemical signal that is released by cells and has a local effect on the same cell type as that from which the chemical signal is released
autocrine chemical signal
Chemical signals that are secreted into the environment and modify the behavior and physiology of other individuals are called
Norepinephrine and acetylcholine are examples of what types of intercellular chemical signals?
Neurohormones are intercellular chemical signals that are
produced by neurons and act like hormones
___________ are released by cells and affect other cell types locally without being transported in blood.
paracrine chemical signals
The lipid hormones are either ___________ or derivatives of fatty acids.
- are not secreted at a constant rate
- function to regulate the rates of many activities in the body
- secretion rate is controlled by negative feedback mechanisms
- help maintain homeostasis
Hormones can be any type of molecule except
Estrogen, progesterone, testosterone, and glucocorticoids are examples of
Epinephrine, norepinephrine, and thyroid hormones are examples of
amino acid derivatives
Increased blood glucose causes increased insulin secretion from the pancreas. This is an example of
nonhormonal regulation of hormone secretion
1. have a long half-life
2. bind to intracellular receptors
Hormones with a short half-life regulate activities that have a __________ onset with a __________duration.
Arrange in order the correct after parasympathetic neurons are stimulated
- action potentials travel through parasympathetic neurons
- acetylcholine is released
- pancreatic cells depolarize
- insulin is secreted
TRH stimulates the secretion of TSH, which stimulates the secretion of thyroid hormones. Thyroid hormones inhibit TRH and TSH secretion. This is an example of
hormonal regulation of hormone secretion
The monthly change in secretion of reproductive hormones that occurs in women during their reproductive years is an example of
cyclic hormone regulation
Give an example of positive-feedback regulation in the endocrine system
before ovulation, and increase in LH causes an increase in estrogen, which causes and increase in LH
Hormones act at specific target organs because these organs contain ______ specific for the hormones
Growth hormone, secreted by the _____________ gland, stimulates growth of bones and muscle
______________ (hormone) from the anterior pituitary stimulates secretion of cortisol from the _________________(gland). The anterior pituitary consists of ____________ tissue
The parafollicular cells of the ____________ gland produce _________, a peptide hormone that lowers plasma calcium levels.
Hormones secreted by the pancreatic islets of the pancreas include _________ from the a cells and __________ from the B cells. Which of these hormones raise blood glucose levels?
_________________ (hormone) is a stimulus for sperm production in the male and maturation of ovarian follicles in the female.
FSH - Follicle-Stimulating Hormone
_____________ secreted by the pineal gland, helps regulate body activities with the light-dark cycle
The outermost layer of the adrenal cortex primarily produces the hormone _________ which acts on the ________(organ) to increase ________(electrolyte) reabsorption
The ________________ (gland) is a modified sympathetic ganglion producing the amine hormones known as ______________. This category of amine hormones includes both ________ and ____________(two hormones)
Examples of peptides (proteins)
growth hormone GH
Examples of Amides
Examples of steroids
Thyroid hormones include two molecules called _______ and _____
T3 consists of two ______ molecules plus _____ iodine molecules
The anterior pituitary is composed of ____________ tissue
epithelial / glandular
Name the six classic hormones whose functions are well-known
- TSH - Thyroid Stimulating Hormone
- FSH - Follicle Stimulating Hormone
- LH - Lutenizing Stimulating Hormone
- ACTH - Adrenocorticotropic Hormone
- GH - Growth Hormone
- PRL - Prolactin
everything - HR, BP, menstruation, RR, stimulates the release of T3 and T4 - glycoprotein
Stimulates follicule maturation and production of estrogen, stimulates sperm production, stimulates mild production, stimulates ovaries - glycoprotein
Triggers ovulation and production of estrogen and progesterone by the ovary; promotes sperm production, promotes milk secretions - glycoprotein
Promotes release of glucocorticoids and androgens from adrenal cortex, stimulates the stress hormone producing corticol - flight or flight - peptide
Stimulates body growth - protein
Promotes lactation - protein
The scientific study of hormones and the endocrine organs
Hormones are chemical messengers that are released to the __________ and _________effects after a period of a few seconds to several days
elicit target cell
Hormone targets include most cells of the body and regulate the following
growth and development
mobilization of body defenses
have no ducts and release hormones through diffusion
Endocrine glands include
the pituitary, thyroid, parathyroid, adrenal, and pineal glands
Name the organs that contain endocrine tissue
are local chemical messengers that act on the same cells that secrete them
are local chemical messengers that act on neighboring cells, rather than the cells releasing them
Most hormones are _________________ but gonadal and adrenocortical hormones are ______________ derived from ___________
amino acid based
leukotrienes and prostaglandis that derive from arachidonic acid
Cells that have receptors for a given hormone
Water-soluble hormones (all amino acid-based hormones except thyroid hormone) exert their effects how
through an intracellular second messenger that is activated when a hormone binds to a membrane receptor
Lipid-soluble hormones (steroids and thyroid hormone) diffuse how
into the cell, where they bind to intracellular receptors, migrate to the nucleus, and activate specific genes.
is signaled by most amino acid-based hormones, cause the generation of an intracellular second messenger when a hormone binds to a membrane receptor
Cyclic AMP signaling mechanism or the PIP2-calcium signaling mechanism involves what
the G protein-mediated activation of enzymes that results in the activation of protein kinases
Direct gene activation occurs how?
when a lipid-soluble hormone or thyroid hormone binds to an intracellular receptor, which activates a specific region of DNA, causing the production of mRNA and initiation of protein synthesis.
Target cells have specific _______________ or __________ receptors to which hormones can bind.
Name the three factors that target cell response depends on?
- blood levels of the hormone
- relative numbers of target cell receptors
- affinity of the receptor for the hormone
Target cells can change their sensitivity to a hormone by changing what?
The number of receptors
Persistently low levels of hormone can cause ?
a cell to up-regulate, increasing the number of receptors
Persistently high levels of hormones can cause ?
a cell to down-regulate, decreasing the number of hormone receptors
Most hormone synthesis and release is regulated through ___________________
negative feedback mechanisms
Endocrine gland stimuli may be ___________, _____________, or ____________
Critical ions or nutrients that act as stimuli controlling the secretion of hormones
________________ stimulate hormone release, then the stimulus for release is _________
If the secretion of a hormone is in response to hormones produced by other endocrine glands, it follows a
hormonal pattern of secretion
Nervous System modulation allows ________________________
hormone secretion to be modified by hormonal, humoral, and neural stimuli in response to changing body needs.
The concentration of a hormone reflects
its rate of release and the rate of inactivation and removal from the body
The half-life of a hormone:
the duration of time a hormone remains in the blood and is shortest for water-soluble hormones.
Permissiveness occurs when one hormone cannot exert its full effect without
another hormone being present
occurs when more than one hormone produces the same effects in a target cell, and their combined effects are amplified
occurs when one hormone opposes the action of another hormone.
The pituitary gland is stimulated in the _______________ of the skull and is connected to the _______________ via the infundibulum
The pituitary has two lobes....name and describe each
The posterior pituitary - or neurohypophysis - is neural in origin
The anterior pituitary - or andenohypophysis - which is glandular in orgin
The posterior pituitary produces two neurohormones:
oxytocin - which promotes uterine contraction and milk ejection
antidiuretic hormone ADH - which prevents wide swings in water balance
The anterior pituitary hormone produces six hormones, four of which are ______ hormones that ___________secretion of other hormones as well as a ____________
Name the six hormones produced by the pituitary
a prohormone that can be split into adrenocorticotropic hormone, two natural opiates, and melanocyte-stimulating hormone.
Growth Hormone - GH
acts on target cells in the liver, skeletal muscle, bone, and other tissues to cause the production of insulin-like growth factors (IGFs)
Regulates hunger, thirst, sleep and wakefulness plus most of your involuntary mechanism including body temperature
controls all other endocrine glands: influences growth metabolism and regeneration
Posterior - storehouse for oxytocin and ADH
Anterior - everything else
Sends hormones to the thyroid (TSH)
high amounts = inappropriate ADH secretion (SIADH)
low amounts = diabetes insipidus
secrete parathyroid hormone or parathormone, which causes osteoclasts to bread down bone, increases absorption of Ca++ in the kidneys and activates vitamin D which aids in the absorption of calcium from food.
Secretes the hormones necessary for calcium absorption
Regulates your energy and your metabolism, negative-feedback, keeps balance, positive feedback, HR, BP......
Stimulates thyroid gland to release thyroid hormones
low amounts = Cretinism in children and myxedema in adults
high amounts = hyperthyroidism - similar to Graves disease
Aids in the digestion of protein, fats and carbohydrates. Produces insulin which controls blood sugar levels (glucose levels)
Ovaries/testes - gonads
Influences how your body circulates and determines your mental vigor and your sex drive Estrogen and progesterone in females
Gives serotonin - calming hormone
Promotes testosterone production in males
Helps build resistance to disease
promotes release of glucocorticoids and androgens - mineralocorticoids to a lesser extent
High amounts = Cushing's disease
low amounts of prolactin PRL =
poor milk production in nursing women
low amounts of FSH =
failure of sexual maturation
low amounts of GH =
dwarfism in children
low amounts of ADH
high amounts of GH =
Gigantism in children
Acromegaly in adults
The only major secretory product of the pineal gland is
The pancreas is a mixed gland that contains both
endocrine and exocrine gland cells
targets the liver where it promotes glycogenolysis, gluconeogenesis and release of glucose to the blood.
About 80 % of the hormone stored in the adrenal medulla is
epinephrine and 20 % norepinephrine
Adrenal catecholamines produce
brief stress-mediated responses
lowers blood glucose levels by enhancing membrane transport of glucose into body cells and inhibits production through glycogen breakdown or conversion of amino acids or fats to glucose
Adipose tissue produces
Leptin - acts on the CNS to produce a feeling of satiety
resistin - an insulin antagonist
adiponectin - increases sensitivity to insulin
The GI tract contains
enteroendocrine cells throughout the mucosa that secrete hormones to regulate digestive functions.
The atria of the heart contains
specialized cells that secrete atrial natriuretic peptide, resulting in decreased blood volume, blood pressure, and blood sodium concentration
The kidneys produce
erythropoietin, which signals the bone marrow to produce red blood cells
The skin produces
Cholecalciferol and inactive form of V D3
Osteoblasts in skeletal tissue secrete
osteocalcin, a hormone that promotes increased insulin secretion by the pancreas and restricts fat storage by adipocytes.
The thymus produces
thymopoietin, thymic factor, and thymosin, which are essential for the development of T lymphocytes and the immune response.
Catecholamines are produced in the _______________ of the adrenal gland and are classified as _____________ hormones