Ch. 18 Flashcards
(161 cards)
1
Q
What 2 systems coordinate the functions of all body systems?
A
nervous and endocrine
2
Q
How does the nervous system control activities?
A
Through nerve impulses that cause muscles to contract or glands to secrete
3
Q
How does the endocrine system control activities?
A
By releasing chemical messenger molecules called hormones
4
Q
What is the neuroendocrine system and how do they work?
A
It is the nervous and endocrine system that work as a coordinated, interconnecting, tremendous system.
5
Q
What stimulates the release of hormones?
A
The central nervous system?
6
Q
What may hormones do to nerve impulses?
A
Promote or inhibit the generation of them
7
Q
2 types of glands in the body
A
exocrine and endocrine
8
Q
exocrine glands secrete
A
their products (enzymes) into ducts
9
Q
endocrine glands secrete
A
hormones into the interstitial fluid surrounding the secretory cells, which then diffuse into capillaries; ductless
10
Q
what are the endocrine system’s glands?
A
Pituitary, thyroid, parathyroid, adrenal, pineal
11
Q
how are hormones
circulated through the body?
A
via the circulatory system, they regulate
and modify cell activity and metabolism
12
Q
what do hormones only
affect?
A
specific target tissues.
13
Q
what do target cells have?
A
specific receptors to which hormones bind
14
Q
receptor molecules are
constantly being_________
A
synthesized and broken down
15
Q
down regulation
A
may occur under conditions of high
hormone concentration and decreased
surface receptor molecules.
16
Q
up regulation
A
may occur during conditions of low
hormone concentration and high surface
receptor molecules.
17
Q
circulating hormones aka
endocrine are hormones that
A
travel in blood and act on
distant target cells
18
Q
local hormones are hormones that
A
act locally without first
entering the blood stream.
19
Q
2 types of local hormones
A
paracrine, autocrine
20
Q
paracrin
A
local hormones that act on neighboring
cells
21
Q
autocrin are
A
local hormones that act on the same cell
that secreted them
22
Q
lipid soluble hormones include
A
steroids and thyroid hormones
23
Q
water soluble hormones include
A
amines, peptides, and proteins
24
Q
amines are
A
modified amino acids. have an NH3 group.
formed by removal of CO2
25
steroids are made from
cholesterol
26
peptides and proteins are formed from
polypeptides
27
where do most water-
soluble hormones circulate?
in the plasma, in a free, unattached form
28
to what do most lipid soluble
hormones bind? what does
it cause?
bind to transport proteins, which improves
transportability in the blood. causes an
impediment of passage through the kidney
29
typical mechanism of an amine is to use cyclic AMP
as the 2nd messenger; what is the process?
alters the DNA, resulting in the formation of
new proteins. causes a response typical of
that hormone.
steps:
1. hormone binds to receptor, forming a
receptor hormone complex
2. an enzyme in the cell (adenylate cyclase)
is activated by G-protein. G proteins are
activated by the receptors that have bound
to the hormones
3. adenylate cyclase converts ATP into
cyclic AMP (second messenger)
4. cyclic AMP activates protein kinases
(which modify metabolism of cell)
5. phosphorylation (kinase enzymes
transfer a phosphate ion from side chain of
1 protein to another)
6. enzyme phosphodiesterase is an
enzyme that quickly destroys cyclic AMP
(effects of cyclic AMP are brief/alter activity
in target cells
30
why do we need water
soluble hormone binding?
without it, protein and peptide molecules
can’t break through the cell membrane
31
what do water soluble
hormones activate/ what
does that initiate?
activates plasma membrane receptors,
initiating a series of biochemical events
within the target cell
32
what is the first messenger?
water-soluble hormone
33
what is the second
messenger?
produced inside the cell because of the first
messenger (hormone)
34
what does regulation of
hormone secretion do?
normally maintains homeostasis and
prevents overproduction or underproduction
of a particular hormone
35
what is hormone secretion
controlled by
signals from the nervous system, chemical
changes in the blood, and other hormones
36
more hormones secreted,
_____ effect on target
hormone
greater
37
what 2 things does the
secretion of hormones
affect?
1. modifies target organ
2. endocrine gland that secreted it; inhibits
further hormone production (feedback
inhibition)
38
hypothalamus is
the major integrating link between the
nervous and endocrine systems
39
what 2 glands regulated
virtually all aspects of
growth development,
metabolism, and
homeostasis?
hypothalamus and pituitary gland
(hypophysis)
40
anatomy of pituitary gland
rests in the sphenoid bone on the
hypophyseal fossa and is divided into two
lobes; attaches to the brain by the
infundibulum (aka hypophyseal stalk)
41
what is the anterior pituitary
gland aka adenohypophysis
supplied by?
the hypophyseal portal (branches of
internal carotid) because it does not have a
direct blood supply
42
what are the hormones of
the anterior pituitary gland
controlled by?
releasing or inhibiting hormones produced
by the hypothalamus
43
hormones of the anterior
pituitary gland
many are tropic hormones; has a target
organ other than endocrine gland:
human growth hormone (HGH) or
somatotrophin (STH)
Thyroid stimulating hormone (TSH)
Follicle Stimulating Hormone (FSH) and
luteinizing hormone (LH)
Prolactin (PRL)
Adrenocorticotrophic hormone (ACTH) and
melanocyte-stimulating hormone (MSH)
44
HGH or somatotrophin is secreted by
somatotrophs
45
Thyroid stimulating hormone
(TSH) is secreted by
thyrotrophs
46
Follicle Stimulating hormone
(FSH) and luteinizing
hormone (LH) are secreted by
gonadotrophs
47
Prolactin (PRL) secreted by
lactotrophs
48
Adrenocorticotrophic hormone (ACTH) and melanocyte-stimulating hormone (MSH) are secreted by
corticotrophs.
49
hypothalamic regulating hormones and feedback inhibition mechanisms regulates
the secretion (release) of anterior
pituitary gland hormones
50
what is the secretion of HGH
dependent upon?
hypothalamic releasing factors (GHRF,
GHIRF)
51
HGH
stimulates general body growth and
regulates various aspects of metabolism
involving muscle, bone, adipose tissue
(lipolysis - breaks down fat), and acts
synergistically with insulin.
52
"synergistically"
combined effects of 2 agents are greater
than 1
53
hypersecretion
too much
54
hyposecretion
too little
55
HGH hypersecretion
childhood: giantism
adulthood: acromegaly
56
acromegaly
bones no longer grown in length - they
thicken (esp. brow line, mandible) massive
hands and feet. die young (heart/kidney
failure)
57
HGH hyposecretion
pituitary dwarfism and hypoglycemia; slow
growth rate; premature closure of epiphysis
58
Thyroid stimulating hormone
regulates synthesis and secretion of thyroid
gland hormones
59
what is secretion of thyroid
stimulating hormone
controlled by?
TRH aka thyroid releasing hormone
(thyrotrophin)
60
what happens to Thyroid releasing hormone factor at
high hormone levels? low?
high - TRF inhibited
low - TRF stimulated
61
TSH hypersecretion
hyperthyroidism
62
TSH hyposecretion
hyperthyroidism; thyroid gland atrophies
63
secretion of follicle
stimulating hormone (FSH)
is controlled by?
GnRF aka gonadotropin releasing factor
64
what does FSH stimulate in
FSH
follicle (egg cell) production
65
what does FSH stimulate in
men?
sperm cell production
66
Luteinizing Hormone (LH)
secretion is controlled by?
GnRF aka gonadotropin releasing factors
67
what does LH stimulate in
women?
2 sex hormones - progesterone and
estrogen
68
what does LH stimulate in
men?
secretion of testosterone in seminiferous
tubes
69
Leydig cells
cells that produce testosterone
70
Prolactin (PRL) secretion is
regulated by
PIF aka prolactin inhibiting factor
71
what does PRL stimulate?
when used with estrogen and
progesterone, PRL initiates and maintains
milk secretion
72
what does prolactin do in
males?
increase the effects of LH
73
secretion of adrenocorticotrophic
hormone (ACTH) is regulated by
CRF aka corticotroph
releasing factor
74
what does ACTH control?
the production and secretion of hormones
of the cortex and adrenal glands, namely
glucocorticoids.
75
ACTH hypersecretion examples
Cushing's Disease; moon face,
expressionless, Dowager’s hump
76
ACTH hyposecretion examples
Addison's disease; bronze skin
77
Melanocyte-stimulating
hormone (MSH) secretion is regulated by
ACTH
78
what does MSH do?
increase melanin production in the skin;
increase the number of melanocytes. if you
inject MSH, causes intense darkening of
skin
79
cells of the posterior pituitary
gland
pituicytes.
80
do pituicytes synthesize
hormones?
no
81
hypothalamohypophyseal
tract
a neural connection between the
hypothalamus and the neurohypophysis
82
what does the neural
connection
(hypothalamohypophyseal
tract) resemble?
support cells of the nervous system;
support axon terminals in gland
83
2 hormones made by hypothalamic nuclei and stored in the posterior pituitary gland
oxytocin, antidiuretic hormone
84
"Hypothalamic nuclei"
paraventricular and supra optic; collections
of cell bodies; axons of these cell bodies
terminate in posterior pituitary
85
oxytocin
stimulates contraction of the uterus and
milk ejection from the mammary glands
86
hyposecretion of oxytocin effects
difficult labor; inability to nurse
87
antidiuretic hormone regulates
body water balance through its action on the kidneys
88
secretion of antidiuretic
hormone regulated by
osmoreceptors
89
osmoreceptors
sense organs that detect solute
concentration in body fluids
90
what does ADH cause?
where does it come from?
decreased water excretion; comes from
supraoptic
91
hypersecretion of
antidiuretic hormone
high blood pressure (vasoconstricts blood
vessels)
92
hyposecretion of antidiuretic
hormone
diabetes insipidus - excretion of very dilute
urine (15-20 L/day)
93
anatomy of larynx
located just below the larynx and has right and left lobes connected by the thyroid isthmus
94
what does the thyroid
consist of?
thyroid follicles composed of follicular cells, which secrete 2 hormones (thyroxin [t4, tetraiodothyronine] which is most abundant, and t3 aka triiodothyronine (most active)
95
follicular cells
simple cuboidal
96
which hormone from the
follicular cells is most
abundant? most active?
abundant - t4
active - t3
97
how are thyroid hormones
synthesized?
from iodine and the amino acid tyrosine
within a glycoprotein called thyroglobulin
and then t3 and t4 are transported in the
blood by TBG (thyroxin binding globulin -
plasma protein).
98
what does thyroglobulin
represent?
inactive t3, t4
99
what can thyroid hormones
regulate?
oxygen use and basal metabolic rate,
cellular metabolism, and growth and
development
100
hyposecretion of Thyroid
hormone
in a fetus - can delay development in CNS,
in children - mental retardation
101
what is thyroid hormone
secreted by?
feedback inhibition involving the
hypothalamus, the pituitary gland, and TSH
102
what role does TSH play in
secretion of thyroid hormone
maintaining thyroid follicles which produce
t3 and t4; stimulates follicles to take up
iodine from blood and incorporate it into t3s
and t4s. it also increases the size of the
follicles
103
hypersecretion of thyroid
hormone
hyperthyroidism (grave's disease) -
tachycardia (100-160), heart failure,
nervous excitability, elevated body temp,
flushed moist skin, decrease tolerance to
heat, increase tolerance to cold,
hyperglycemia - can lead to thyroid storm
104
what happens to TSH with
low levels of t3 and t4?
increases. and vice versa.
105
hyposecretion of thyroid
gland
hypothyroidism
infants and children: cretinism
adults: myxedema (Gulls’ disease)
106
cretinism
slow mental/physical growth, dwarfism,
bradycardia, mental retardation, low body
temp, thick dry skin
107
myxedema
slow mental/physical growth, dwarfism,
bradycardia, mental retardation, low body
temp, thick dry skin and infertility, loss of
body hair
108
4 reasons for
hypothyroidism
1. failure of the hypothalamus to release
TRF (thyroid releasing factors).
2. failure of pituitary gland to release TSH
3. failure of thyroid gland
4. deficiency in iodine
109
thyrocalcitonin
produced by cells lying outside the thyroid
gland called C cells aka parafollicular cells
110
do you get a goiter with
hypo or hyper?
both
111
what turns on
thyrocalcitonin?
high blood calcium levels
112
what is thyrocalcitonin
secretion regulated by?
calcium levels in the blood
113
what does thyrocalcitonin
do?
promote uptake of calcium by bone tissue
thus causing a decrease in blood calcium
levels
114
where are the parathyroid
glands?
embedded on the posterior surface of the
thyroid
115
what cells are in the
parathyroid gland?
principal cells aka parathormone aka chief
cells, which produce parathyroid hormone
116
parathyroid hormone
regulated calcium homeostasis by
increasing blood calcium levels through its
effect on the kidneys, bone, and GI tract -
opposite of thyrocalcitonin
117
when is parathyroid
hormone activated?
when blood calcium levels drop. calcium is
taken out of bone and put to blood
(increased osteoclast activity)
118
what is secretion of
parathyroid hormone
regulated by?
feedback inhibition based on blood calcium
levels
119
hypersecretion of
parathyroid hormone
hyperparathyroidism: increase calcium
levels causes decreased excitability of
muscle and nerve tissue. muscle
weakness, lethargy, fragile bones, kidney
stones
120
hyposecretion of parathyroid
hormone
hypoparathyroidism: decreased calcium
levels, increase excitability to muscle and
nerve tissue, muscle strength, no lethargy,
strong bones, cramps, spasms, convulsions
121
where are the adrenal
glands?
superior to the kidneys and have 2 layers -
internal and external
122
external tissue of adrenal
glands
adrenal cortex: divided into three zones that
secrete different hormones chemically
related to cholesterol and androgens (sex
hormones); zona glomerulosa, zona
fasciculata, zona reticularis
123
zona glomerulosa
outer zone. secretes mineralocorticoids.
closest to capsule
124
zone fasciculata
middle zone. secrete glucocorticoids
125
zona reticularis
inner zone. secretes androgens
126
mineralocorticoids
decrease sodium and water excretion
(increase retention) and increase
potassium excretion (decrease retention)
into the urine.
127
what is secretion of
mineralocorticoids regulated
by?
the renin angiotensin pathway
128
target organ for adrenal
glands
kidney
129
renin-angiotensin pathway
angiotensinogen -->renin--.angiotensin I--
>angiotensin CE-->angiotensin II
130
angiotensin CE
converting enzyme secreted by type 1
alveolar cells
131
renin
secreted by kidney. converts
angiotensinogen into angiotensin I
132
hypersecretion of
mineralocorticoids
edema (increased ECF water)
increased: blood volume, cardiac output,
blood pressure. congestive heart failure
133
hyposecretion of
mineralocorticoids
hypovolemia, shock, death; decreased in
blood volume, cardiac output, blood
pressure. shock (cause of death), sodium
and ECF water lost
134
glucocorticoids; 4 actions on
the body
1. gluconeogenesis and inhibition of protein
synthesis
2. release of stored fat from adipose tissue
3. suppress immune system to reduce
lymphocyte and antibody products
4. anti-inflammatory affect causes heat,
redness swelling pain
135
what is secretion of
glucocorticoids regulated by
feedback inhibition involving ACTH,
cortisol, and CRH aka corticotropic
releasing hormone
136
effect of glucocorticoid
hypersecretion
Cushing's disease; suppressed immune
system, loss of body protein/muscle, tumor
of adrenal pituitary, atrophy, thin skin,
hyperglycemia
137
effect of glucocorticoid
hyposecretion
Addison’s disease; bronze skin, muscle
weakness, GI disturbances, low BP, renal
failure
138
adrenogenital syndrome
involves the adrenal cortex, gonads, and
pituitary hypothalamus - the primary defect
is the inability of the adrenal cortex to
produce cortisol (inhibiting ACTH
secretion); ACTH levels increase,
gonadotropin production decreases and
egg and sperm cells are not produced ..
result -sterility
139
what effect do high levels of
cortical androgens have on
women?
masculinizing
140
adrenal medulla
consists of hormone producing cells called
chromaffin cells which surround large
blood, filled sinuses
141
what are medullary
secretions of adrenal
medulla? what response is it
similar to?
epinephrine and norepinephrine;
sympathetic
142
hypersecretion of adrenal
medulla
pheochromocytoma (marked hypertension)
143
pancreas
a flattened organ located posterior and
slightly inferior to the stomach
144
what is the pancreas
classified as?
endocrine and exocrine gland; it secretes
both hormones into the blood and digestive
enzymes into the duct systems.
145
histology of endocrine
portion of pancreas
consists of pancreatic islets or islets of
Langerhans
146
4 types of cells in the islets
of Langerhans
alpha cells, beta cells, delta cells, f cells
147
alpha cells
produce the hormone glucagon
148
beta cells
produce the hormone insulin
149
delta cells
produce somatostatin; inhibits growth
hormone insulin release
150
f cells
produce pancreatic polypeptide
151
what does the exocrine
portion consist of
(pancreas)?
clusters of digestive enzyme-producing
cells called pancreatic acini that empty into
the duodenum of the small intestine
through the duct of Wirsung
152
what is the secretion of
insulin regulated by?
feedback inhibition
153
what does insulin regulate?
carbohydrate, protein, and fat metabolism
mainly in muscle, adipose, and liver tissues
154
hypersecretion of insulin
hypoglycemia (glucose levels in the blood
fall below 100 mgs/100 mls)
155
effect of hyposecretion of
insulin
juvenile type I and adult-onset type II
diabetes mellitus
156
juvenile type I diabetes
before age 30. rapid onset. no insulin
production. auto immune. t-lymphocytes
attack beta cells. genetic defect on
chromosome 11. need insulin
157
adult-onset type II diabetes
middle age, FFF (fat female forty), make
insulin but a decreased sensitization of
insulin receptors. use diet and exercise
may need some insulin help
158
ovaries
located in the pelvic cavity and produce sex
hormones (estrogen and progesterone)
related to development and maintenance of
female sexual characteristics, reproductive
cycle, pregnancy, lactation, and normal
reproductive functions. they also produce
inhibin and relaxin
159
testes
lie inside the scrotum and produce sex
hormones (testosterone primarily) related to
the development and maintenance of male
sexual characteristics and normal
reproductive functions. they also produce
inhibin.
160
the thymus gland secretes
several hormones related to
____
immunity
161
what promotes the
proliferation and maturation
of t lymphocytes (a WBC
involved in immunity)?
thymosin, thymic humoral factor, thymic
factor, and thymopoietin.
