chapter 18: endocrine sytem Flashcards
1
Q
why fo the nervous and endocrine system work together?
A
to coordinate the functions of all body systems
2
Q
difference between how nervous system acts and how the endocrine system acts
A
Nervous system acts through the action of
neurons, and neurotransmitters they
secrete
◦ The endocrine system acts through hormones
produced by cells or endocrine glands
3
Q
true or false some mediators can act as both neurotransmitters and hormones
A
true, ex: norepinephrine.
but each is controlled by different mechanisms
4
Q
what are examples of hormones controlling different processes
A
Regulation of different processes:
◦ Composition and amount of interstitial fluid
◦ metabolism
◦ biological clock
◦ contraction of cardiac & smooth muscle
◦ glandular secretion
◦ some immune functions
◦ growth & development
◦ reproduction
5
Q
exocrine glands bs endocrine glands. Give examples
A
Exocrine glands
◦ secrete products onto an epithelial surface (into body cavity, or body surface);
may or may not use a duct
◦ sweat, oil, salivary glands, pancreas…
Endocrine glands
◦ secrete hormones into interstitial fluid, and normally ends up in the bloodstream
◦ pituitary, thyroid, parathyroid, adrenal
6
Q
which organs secrete hormones as secondary function?
A
◦ Some organs secrete hormones as a 2ndary function
◦ hypothalamus, thymus, pancreas, ovaries, testes, kidneys, stomach, liver, small
intestine, skin, heart & placenta
7
Q
what are the 3 different forms of endocrine signalling
A
- endocrine cells sends hormones through blood to distant target cells, which then land on hormone receptor
- a paracrine cell sends paracrines (hormones) to a nearby target cell. the paracrines bind to paracrine receptors
an autocrine cell signals itself. The hormones attach to the autocrine receptor
8
Q
What is a hormone?
a) a molecule found in the cytoplasm of a cell
b) a molecule found in the nucleus of a cell
c) a molecule released by a cell
d) a molecule released by a neuron specifically
A
c) a molecule released by the cell
9
Q
How does a hormone reach its target cell?
a) It usually travels through blood
b) It usually travels through lymph vessels
c) It travels through the nervous system
d) All the above
A
A
10
Q
How does a hormone “know” what cell to
influence?
a) It only uses blood vessels that get to the target organ
b) It binds to hormone receptors found on target cells
c) It binds to all cells, but only target cells respond to the binding
d) All mechanisms above are possible
A
b) it binds to hormone receptors found on target cells
11
Q
what needs to happen for a cell to be activated by hormones
A
To activate a cell, a hormone needs to bind to its receptor noncovalently
(reversibly; non permanently)
12
Q
what are 3 factors that determine the level of activation of a target cell?
A
◦ Blood levels of hormones
◦ Number of receptors on target cell (if don’t receive a lot of hormones will grow more receptors. The opposite is also true)
◦ Affinity of receptor for its hormone
13
Q
how do target cells change the number of receptors present
A
Hormone receptors are continually being synthesized and destroyed
1. ◦ Down-regulation
◦ cell responds to excess hormone by decreasing number of receptors
◦ surface receptors undergo endocytosis and are degraded
◦ decreases sensitivity of target cell to hormone
◦2. Up-regulation
◦ cell responds to deficiency of hormone by increasing number of receptors
◦ target tissue more sensitive to the hormone
14
Q
what is the general mechanism of action for hormones
A
- Hormone binds to receptor
◦ receptor located on plasma membrane or in cytoplasm depending on type of
hormone - Binding of hormone to receptor triggers a response in the target cell
◦ synthesize new molecules
◦ let substances in or out of cell
◦ alter metabolism (speed up or slow down reactions)
15
Q
what are the 2 chemical classes of hormones
A
- Lipid soluble hormones
- water-soluble hormones
16
Q
how would you administer lipid soluble hormones vs water soluble hormones?
A
lipid soluble you would take through pills and water soluble you would take intravenously
17
Q
what are examples of lipid-soluble hormones?
A
Steroids (e.g., estrogens, testosterone, glucocorticoids)
◦ Derived from cholesterol
Thyroid hormones (T3, T4)
◦ Iodination of tyrosine
Nitric oxide – NO (gas)
18
Q
what are examples of water-soluble hormones?
A
epinephrine, serotonin, histamine, oxytocin, ADH, prostaglandins
19
Q
how are lipid soluble proteins transported in the blood
A
◦ Lipid-soluble hormones are hydrophobic – cannot travel in blood easily (plasma = water)
◦ Lipid-soluble hormones are generally bound to a transport protein (e.g., albumin)
◦ Transport protein is amphipathic
◦ prevents clumping and increases molecule size, so less likely to be filtered out by kidneys
◦ Hormone dissociates from transport protein as it approaches tissues, and
diffuses into cells
20
Q
describe the action of lipid-soluble hormones
once they get to the cell
A
- lipid-soluble hormones diffuses into cell
- hormones binds to receptor in cytoplasm or nucleus which alters gene expression
- newly formed mRNA direct synthesis of specific proteins on ribosomes. The cell’s activities change because of the new proteins
21
Q
what are amine hormones and what are some examples? are they water soluble or lipids soluble?
A
Amine hormones = modified amino acids (small)
◦ e.g., epinephrine from tyrosine; histamine made from histidine; serotonin
from tryptophan
They are water soluble
22
Q
peptide/ protein hormones examples? Are they water or lipid-soluble?
A
◦ Peptide (3-49aa): antidiuretic hormone (ADH), oxytocin
◦ Protein (50-200aa): human growth hormone (hGH), insulin
water-soluble
23
Q
what are eicosanoid hormones and what are some examples? ARe they water or lipid soluble?
A
water soluble
Eicosanoid hormones = made from fatty acids (oxygenation makes it polar)
◦ e.g., prostaglandins
24
Q
how are water-soluble hormones transported in the blood
A
since they are hydrophilic they travel freely in blood
25
what are the steps in the action of water-soluble hormones?
1. binding of hormone (first messenger) to its receptor activates G protein which activates adenylate cyclase
2. Activated adenylate cyclase
converts ATP to cAMP, which
serves as a second messenger
to activate protein kinases
3. Activated protein
kinases phosphorylate
cellular proteins
4. Millions of phosphorylated
proteins cause reactions that
produce physiological responses
26
A major difference between lipid-soluble
hormones and water-soluble hormones is
a) Lipid-soluble hormones bind to receptors; water-soluble
hormones don’t
b) Water-soluble hormones bind to receptors; lipid-soluble
hormones don’t
c) Lipid-soluble hormones increase metabolism; water-soluble
hormones decrease metabolism
d) Lipid-soluble hormones enter the cell; water-soluble hormones
don’t
D
27
Which chemical class of hormones is NOT
matched correctly?
a) Nitric oxide – lipid soluble
b) Steroids – lipid soluble
c) T3 and T4 – water soluble
d) Catecholamines – water soluble
C
28
Which gland or organ is not strictly classified
as an endocrine gland?
a) Thyroid gland
b) Adrenal gland
c) Pancreas
d) Pineal gland
c) pancreas
29
what things can trigger the release of hormones from glands
(it's usually other hormones)
1. Humoral stimuli
- Hormone is released in direct response to changing levels of certain chemicals
in blood or body fluids
2. Neural stimuli
◦ Nerve impulses can trigger the release of hormones from certain glands
3. Hormonal stimuli
◦ Hormones can be released in response to other hormones
30
describe the regulation of hormones secretion? (feedback systems)
Most hormonal regulatory systems work
via negative feedback, but a few operate
via positive feedback
31
describe hormone secretion
| how often released
Release of most hormones occurs in short bursts, with little/no secretion
between bursts.
When stimulated, an endocrine gland will release its hormone in more frequent
bursts, increasing its concentration in the blood
32
what happens in the absence of stimulation?
| hormones
The blood level of the hormone decreases
33
Which of the following is NOT true?
a) Secretion of hormones occurs in short bursts
b) Signals from the nervous system regulate hormone secretion
c) Chemical changes in the blood may determine concentration of
hormone release
d) Most hormone systems function under a positive feedback
system
D)
34
hat does the hypothalamus regulate?
| endocrine system
The hypothalamus is part of the brain
The hypothalamus regulates the autonomic nervous system, body temperature,
thirst, hunger, sexual behaviour, fear, anger
35
what does the hypothalamus link and what gland does it control?
The hypothalamus links the
nervous and endocrine
systems
It controls the pituitary gland
through the production of 9 (or
more) different hormones
36
how does the hypothalamus know when to produce hormones?
Hypothalamus receives signals from different parts of brain
It then sends signals to the pituitary gland, which produces several hormones
that regulate many body functions
37
what is the function of the infundibulum?
The infundibulum
attaches the pituitary
gland to the
hypothalamus
38
describe the structure of the pituitary gland
The pituitary gland attaches to
the hypothalamus and has two
anatomically and functionally
separate lobes
39
what are the steps of activating the anterior pituitary gland
1. The hypothalamus secretes
hormones to activate the
anterior pituitary gland
2. The anterior pituitary gland (adenohypophysis) secretes
hormones in response to hypothalamic hormones
40
how are hypothalamic hormones delivred to the pituitary gland?
what are the two steps?
Hypothalamic hormones are
delivered to the anterior
pituitary gland via the
hypophyseal portal system -
A portal system connects two
capillary beds together
1. Neurosecretory cells
release hormones into the
primary plexus of the
hypophyseal portal system
2. Hormones go from the
primary plexus to the
secondary plexus of the
hypophyseal portal system
41
describe the relation between human growth hormone and insulin-like growth factors
42
what happens when there is hypersecretion of hGH before closing of the epiphyseal plates (in childhood)
Hypersecretion of hGH before closing of epiphyseal plates
(in childhood) causes gigantism. Abnormally tall, but well
proportioned
43
what happens if there is hypersecretion of hGH after closing the epi[hyseal plates (in adults)
Hypersecretion of hGH after closing of epiphyseal plates
(in adults) causes acromegaly (enlarged extremities) -
bones of hands, feet and face are still responsive to hGH
44
what happens when there is hyposecretion of hGH
Hyposecretion of hGH results in pituitary dwarfism. Short
but normal proportions. If detected before puberty, can
treat with exogenous hGH
45
Which of the following do you think would
lead to the release of hGH?
a) High blood glucose levels
b) Low blood glucose levels
B because low levels would make hgiher blood glucose levels)
I think :)
46
Which of the following would lead to the
release of hGH?
a) High levels of amino acids in blood
b) Low levels of amino acids in blood
Hint: think about what effect hGH has on amino acid levels in blood
A
47
Which of the following would lead to the
release of hGH?
a) High levels of fatty acids in blood
b) Low levels of fatty acids in blood
B because you break the fatty acids when low levels of glucose we need to break down fats to have more fatty acids
48
what does Thyrotropin-releasing hormone (TRH) tigger? explain the process
Thyrotropin-releasing hormone
(TRH) from the hypothalamus
triggers the release of thyroid
stimulating hormone (TSH)
from the anterior pituitary
In response to TSH, the
thyroid gland produces
and releases thyroid
hormones (T3 and T4)
Thyroid hormones are
involved in the regulation
of metabolism
49
what does Gonadotropin-Releasing Hormone (GnRH) from the hypothalamus trigger?
Gonadotropin-Releasing Hormone (GnRH) from
hypothalamus triggers the release of follicle stimulating hormone (FSH) and Luteinizing
hormone (LH) from the anterior pituitary
The ovaries and the
testes respond to FSH and to LH
Leads to production of sex
hormones (estrogens,
progesterone, testosterone)
Leads to development of
gametes (oocytes and sperm)
50
what does prolactin (PRL) do?
Prolactin-Releasing Hormone (PRH) and Prolactin-inhibiting Hormone (PIH) from the hypothalamus control the release of prolactin (PRL) from the anterior pituitary
The mammary glands respond by altering
milk production
Together with other hormones, PRL initiates and maintain milk production
and secretion
51
what does Adrenocorticotropic Hormone (ACTH) do?
Corticotropin-releasing hormone
(CRH) from the hypothalamus
stimulates the release of
adrenocorticotropic hormone
(ACTH) from the anterior pituitary
The cortex of the
adrenal glands
respond by releasing
glucocorticoids
Glucocorticoids provide resistance to stress and act as anti
inflammatory agents
52
what does Melanocyte-Stimulating Hormone (MSH) do?
Corticotropin-releasing hormone
(CRH) from the hypothalamus
stimulates the release of
melanocyte-stimulating hormone
(MSH) from the anterior pituitary
The melanocytes and
parts of the brain
respond to MSH
Melanin is produced
May play a role in
certain brain
functions? (appetite
and sexual arousal)
53
true of flase the posterior pituitary lobe synthesises hormones?
false
54
what are the steps in hormone delivery to posterior pituitary gland
1. Neurosecretory cells
synthesize hormones in
the hypothalamus
2. Hormones are transported
down the axons located in the
infundibulum and the
posterior pituitary lobe
3. Hormones are stored in
the posterior pituitary lobe,
in the axon terminals of
neurosecretory cells, until
they need to be released
4. Hormones - oxytocin and
antidiuretic hormone (ADH)
are released in the capillary
plexus of the infundibular
process
55
s the capillary plexus of the infundibular
process part of a portal system?
a) Yes
b) No
A) yes
56
what is the role of oxytocin when a female is going through delivery?
During delivery
◦ Oxytocin release enhances muscle contraction of uterus
(+ feedback)
◦ Synthetic oxytocin often used to induce labor
57
what is the role of oxytocin after a female delivers the baby?
*After delivery–uterine contractions necessary for expulsion of placenta–stimulates ejection of milk from breast
58
Oxytocin is made by the:
a) Posterior pituitary
b) Adenohypophysis
c) Anterior pituitary
d) Hypothalamus
e) Milk ducts
d) hypothalamus
59
what are the function of antidiuretic hormone (ADH)?
Functions in increasing blood pressure by:
◦ decreasing urine production
◦ decreasing sweat production
◦ Increasing vasoconstriction
In other words, ADH helps keep water in
60
Which of the following situations would lead to
the release of ADH?
a) Dehydration
b) Overhydrating
c) High blood pressure
d) a and c
a) dehydration
61
negative feedback mechanism of ADH secretion
62
what happens when there is hyposecretion of ADH
leads to a condition called Diabetes Insipidus
excretion of large amounts of dilute urine
◦ urine output rises from 1-2 L/day to ~ 20 L/day
subsequent dehydration and thirst results
63
Which statement is correct regarding the
relationship between the hypothalamus and
pituitary gland?
a) Releasing hormones are secreted by the anterior pituitary
b) The hypothalamus is ‘controlled’ by the pituitary gland
c) The posterior lobe of the pituitary secretes inhibiting hormones
d) The hypothalamus secretes releasing and inhibiting hormones
that influence the pituitary gland
d) the hypothalamus secretes releasing and inhibiting hormones that influence the pituitary gland
64
How does a hormone “know” what cell to
influence?
a) It only uses blood vessels that get to the target organ
b) It binds to hormone receptors found on target cells
c) It binds to all cells, but only target cells respond to the binding
d) All mechanisms above are possible
B
65
A major difference between lipid-soluble
hormones and water-soluble hormones is
a) Lipid-soluble hormones bind to receptors; water-soluble
hormones don’t
b) Water-soluble hormones bind to receptors; lipid-soluble
hormones don’t
c) Lipid-soluble hormones increase metabolism; water-soluble
hormones decrease metabolism
d) Lipid-soluble hormones enter the cell; water-soluble hormones
don’t
D
66
Which statement is correct regarding the
relationship between the hypothalamus and
pituitary gland?
a) Releasing hormones are secreted by the anterior pituitary
b) The hypothalamus is ‘controlled’ by the pituitary gland
c) The posterior lobe of the pituitary secretes inhibiting hormones
d) The hypothalamus secretes releasing and inhibiting hormones
that influence the pituitary gland
D
67
Which of the following do you think would
lead to the release of hGH?
a) High blood glucose levels
b) Low blood glucose levels
Hint: think about what effect hGH has on blood glucose levels
B ; when low-blood glucose, the hGH will be released to stimulate the breakdown of glycogen
68
what is the function of the thyroid gland
| (what do their hormones do?)
Secretes hormones that affect metabolic rate and
calcium levels in body fluids.
69
describe the histology of thyroid gland
Each thyroid follicle is formed
of follicular cells (simple
cuboidal epithelium)
Large amounts of proteins
(Thyroglobulin) are stored in
the follicles
Each thyroid follicle is formed
of follicular cells (simple
cuboidal epithelium)
Follicular cells use thyroglobulin to
make thyroid hormones (T3 and T4)
Parafollicular cells (in between the
follicles) produce the hormone
calcitonin
◦ It lowers the blood calcium levels
70
what do thyroid hormones T3 and T4 do? which one is more abundant and which one is more potent?
T3 & T4 influence almost all body cells–increase metabolic rate–increase body temp –stimulate protein synthesis–increase ATP generation–stimulate breakdown of fats (for ATP) –stimulate Na+/K+ pump synthesis–regulate bone and nervous tissue growth
T4 more abundant than T3
T3 more potent than T4
T4 converted to T3 in body cells
71
steps in the formation, storage and release of thyroid hormones
1. Iodide trapping
2. Synthesis of thyroglobulin (TGB)
3. Oxidation of iodide
Required for iodine to bind to tyrosine
4. Iodination of tyrosine
◦ Tyr + 1 Io = T1; Tyr + 2 Io = T2
5. Coupling of T1 and T2 to form colloid
◦ T1 + T2 = T3; T2 + T2 = T4
6. Pinocytosis and digestion of colloid
7. Secretion of thyroid hormones
8. Transport in the blood
72
what are the different types of thyroid gland disorders
Grave’s disease – most common cause of
hyperthyroidism
◦ Autoimmune disease that causes production of
antibodies that mimic TSH
◦ Weight loss, nervousness, tremor, exophthalmos
(edema behind eyes)
Goiter = enlarged thyroid (can be
due to dietary iodine deficiency)
Can lead to hyper-, hypo-, or
normal thyroidism
73
what are the steps in the control of T3 and T4 secretion?
1. When T3/T4 levels drop, hypothalamus
secretes thyrotropin-releasing hormone (TRH)
2. anterior pituitary secretes thyroid-stimulating
hormone (TSH)
3. Thyroid follicular cells in thyroid produce T3
and T4
4. elevated levels of T3 inhibit the production of
TRH and TSH (negative feedback
74
Which of the following is an effect of the thyroid hormones?
a) Increases blood cholesterol
b) Increases carbohydrate synthesis
c) Increases oxygen consumption
d) Helps slow down body growth
C
75
Which of the following hormones would
increase in a laboratory animal after a thyroidectomy?
a) Thyroid stimulating hormone (TSH)
b) Thyrotropin-releasing hormone (TRH)
c) Triiodothyronine (T3)
d) Thyroxine (T4)
e) a and b
E
76
what do parathyroid glands do?
Parathyroid glands (behind thyroid gland) release parathyroid hormone (PTH)
77
what is the function of parathyroid hormone?
Main regulator of calcium, magnesium & phosphate levels in blood
◦ increases activity of osteoclasts, which perform bone resorption, leading to
the release of Ca2+ & phosphate from bone into the blood
◦ increases reabsorption of Ca2+ and Mg2+ by kidneys
◦ promotes formation of calcitriol (vitamin D) by kidneys which enhances
absorption of Ca2+ and Mg2+ by intestinal cells
78
what are the steps in the control of the parathyroid hormone
79
The release of calcitonin by the thyroid gland is
triggered by the release of hormones from the
anterior pituitary gland
a) True
b) False
b) False
80
Which statement is NOT true of the interplay
between PTH and calcitriol?
a) Calcitriol increases calcium absorption from foods
b) PTH increases resorption of bone
c) High blood calcium levels increases calcitonin release
d) PTH decreases calcitriol levels
B) false
81
what are the two different kinds of parathyroid gland disorders
Hypoparathyroidism
◦ Low levels of calcium, phosphate, magnesium (cations)
◦ Results in muscle twitches, spasms and tetany (maintained contraction)
Hyperparathyroidism
◦ High levels of calcium, phosphate, magnesium
◦ Excessive bone resorption so that bones become soft and easily fractured
82
acini of pancreas vs iselts of langerhans in pancreas
Acini
◦ exocrine function of pancreas
◦ 99% of pancreas
◦ produce pancreatic juice and produce digestive enzymes
* Islets of Langerhans
* endocrine function of pancreas
* produce hormones
* 1% of pancreas
83
describe the control of the pancreas
| hypoglycemia / hyperglycemia
84
Low blood glucose triggers:
a) Alpha cells to secrete insulin
b) Alpha cells to secrete glucagon
c) Beta cells to secrete insulin
d) Beta cells to secrete glucagon
B)
85
what is diabetes mellitus?
◦ A group of disorders caused by an inability to produce or use insulin
◦ Type I diabetes (juvenile diabetes or insulin-dependent diabetes) mellitus is
caused by an absolute deficiency of insulin.
◦ Often due to autoimmune attack of beta cells
◦ Type II diabetes (insulin-independent diabetes; associated with obesity) is
caused by decreased sensitivity to insulin
◦ E.g., Downregulation of insulin receptor on target cells
86
what happens when you have diabetes mellitus
| symptoms
excessive urine production (polyuria); excessive thirst (polydipsia)
◦ kidneys can’t reabsorb enough water
◦ excessive eating (polyphagia)
◦ because no glucose available to cells
◦ fatty acids broken down for energy
◦ ketone bodies in blood make blood acidic (can lead to “diabetic coma”)
◦ excess glucose damages blood vessels, leading to tissue death and kidney
pathologies
◦ excess lipids in blood leads to atherosclerosis and cardiovascular problems
87
what are the 3 different hormones secreted by the suprarenal cortex?
The suprarenal cortex secretes three different hormones
* glucocorticoids– Include cortisol (aka hydrocortisone - 95% of glucocorticoid
activity), corticosterone and cortisone– role in stress response
* mineralocorticoids – role in maintaining blood volume and electrolytes levels
* androgens– role in male features
88
how to glucocorticoids provide resistance to stress?
◦ promoting protein and fat breakdown for ATP – (keep glucose for brain)
◦ gluconeogenesis - conversion of amino acids and fats to glucose (for ATP)
◦ enhancing vasoconstriction (increase BP)
89
Glucocorticoids have anti-inflammatory and immune suppression effects. explain
Glucocorticoids have anti-inflammatory and immune suppression effects
◦ due to anti-inflammatory effects, glucocorticoids delay tissue repair/wound healing
◦ but they can be used to treat acute and chronic inflammatory diseases
◦ due to immuno-suppressive effects, glucocorticoids are used in organ transplant
and some autoimmune diseases
90
what is Cushing's syndrome?
Hypersecretion of glucocorticoids
Due to tumor or to use of immunosuppresive drugs
muscle wasting resulting in spindly arms and legs
Redistribution of fat resulting in rounded face, hump on back, hanging abdomen
Wound healing is poor, bruise easily
Elevated cortisol levels cause hyperglycemia, osteoporosis, weakness,
hypertension, susceptibility of infections, decreased resistance to stress, mood
swings
91
describe the steos in regulation of glucocorticoid levels
92
describe mineralocorticoids
Steroid hormones that regulate the homeostasis of sodium, potassium and
water
◦ the main mineralocorticoid is aldosterone
Aldosterone promotes sodium reabsorption, thereby promoting water
reabsorption
◦ regulates blood volume and blood pressure
93
describe steps Regulation of Aldosterone:
renin-angiotensin-aldosterone pathway
The RAAS is stimulated by a decrease in blood volume and/or blood pressure
◦ Low BP stimulates juxtaglomerular cells in the kidney to secrete the enzyme
renin
◦ Renin converts the plasma protein angiotensinogen (produced in the liver)
into angiotensin I.
◦ As angiotensin I circulates to the lungs, an enzyme called angiotensin-converting enzyme (ACE) converts angiotensin I to angiotensin II
◦ Angiotensin II stimulates the adrenal cortex to secrete aldosterone (salt and H20 resorption indirectly increases BP), and it is a potent vasoconstrictor
(which directly increases BP
94
Which of the following situations would lead to the
release of aldosterone?
a) Dehydration
b) High levels of sodium
c) Low blood pressure
d) a and c
D
95
Aldosterone:
a) is synthesized by the kidneys in response to a drop in blood
pressure.
b) helps regulate blood pH.
c) production is inhibited by high blood K+ levels
d) would be helpful to restore Na+ levels after eating a bag of
potato chips.
e) promotes relaxation of vascular smooth muscle.
B; by regulating sodium and potassium
96
what are androgens?
Androgens are masculinizing hormones produced by the adrenal cortex
◦ insignificant effect in males (because of testosterone produced by testes)
◦ in female, promote libido and are converted to estrogens
◦ after menopause, all estrogens come from conversion of adrenal androgens
97
what does the suprarenal medulla do and what are the steps?
Produces epinephrine (80%) and norepinephrine (20%)
1. Neurotransmitters from the
hypothalamus trigger cells of
the adrenal medulla to release
the hormones epinephrine and
norepinephrine
2. epinephrine and
norepinephrine cause the
fight-or-flight response
98
what does the release of epinephrine and norepinephrine lead to?
Increased heart rate and force of contraction
Constriction of blood vessels of most viscera and skin
Decrease in digestive activities
Dilation of blood vessels of heart, lungs, brain, and skeletal muscles
Conversion of glycogen into glucose in liver
Dilation of airways
Decrease in blood flow to kidneys, leading to decrease in urine output, water
retention and elevated blood pressure
99
what are the types of stress responses
1. Fight-or-flight response is short-lived and is initiated by nerve impulses from
the hypothalamus
2. The resistance reaction is longer-lasting; it helps the body continue fighting
a stressor long after the fight-or-flight response dissipates. It is initiated
mostly by hormones released from the hypothalamus
3. Eventually, the body runs out of resources and cannot sustain the resistance
phase: exhaustion results
100
Which of the following does NOT happen
after prolonged stress response:
a) Muscle wasting
b) Gluconeogenesis
c) Protein synthesis
d) Lipolysis
e) Immune suppression
C
101
what hormones are produces in the ovaries and what does each one of them do?
◦ Estrogen and Progesterone
◦ regulate the reproductive cycle, maintain pregnancy & prepare mammary glands
for lactation
◦ Also help maintain female secondary sex characteristics (enlargement of the
breasts, widening of the hips at puberty)
◦ Relaxin
◦ helps dilate the uterine cervix during labour and delivery
◦ Inhibin
◦ a protein hormone that inhibits the secretion of FSH
102
what hormones do the testes produce?
◦ produce testosterone
◦ regulates descent of testes, sperm
production & 2nd sexual characteristics
◦ Also produce inhibin
103
what does the pineal gland do?
Releases melatonin – involved in circadian rhythm
104
what does the thymus do?
Secretes several factors involved in T lymphocyte
development and activation, and in various
responses of the immune system
105
what does the heart release
Releases atrial natriuretic peptide (ANP) in response to high blood pressure
106
what hormones do the kidneys release?
Release erythropoietin in response to hypoxia
107
Which of the following is NOT part of the
endocrine system?
a) Kidney
b) Ovaries
c) Hypothalamus
d) Heart
e) All the above have endocrine function
E
