1
Q
what are autocrine chemical messengers released by
A
cells
2
Q
what effect do autocrine chemical signals have on cells (what cells)
A
local effect on the SAME cells
3
Q
what do paracrine chemical messengers act on?
A
locally on nearby cells
4
Q
how many cells types are paracrine chemical messengers released by & where into
A
one cell type into the extracellular fluid
-surrounds other cells
5
Q
what are neurotransmitters released by
A
neurons
6
Q
are neurotransmitters secreted by presynaptic or postsynaptic nerve terminals
A
presynaptic
7
Q
what do neurotransmitters influence
A
postsynaptic cells like other neurons, muscle cells, or glandular cells (acetylcholine)
8
Q
what are endocrine chemical messengers released by & into what
A
certain cells & endocrine glands into the bloodstream
9
Q
what cells do endocrine chemical messengers affect
A
distant cells
10
Q
what is an example of an endocrine chemical messenger
A
estrogen
11
Q
A
12
Q
what do glands do
A
secrete chemical signals (hormones) into circulation `
13
Q
how much hormone is usually released
A
a small amount
14
Q
what is the pathway of hormones
A
transported into bloodstream - transported some distance - act on target tissues
15
Q
what is the purpose of the endocrine system
A
to regulate activities of body
16
Q
what are the similarities of nervous & endocrine systems
A
-both associated with brain & hypothalamus
-the same molecule may be used as a neurotransmitter by the nervous system or a hormone by the endocrine system (epinephrine)
-the systems cooperate with each otheer
17
Q
what does NS secrete into circulatory system
A
neurohormones
18
Q
what is a part of the of the endocrine system that is innervated by the nervous system
A
adrenal medulla
19
Q
what is faster & what lasts longer? NS or ES
A
faster: nervous
longer: endocrine
20
Q
what is half life
A
time for half of the dose to be eliminated
21
Q
what has a long half life
A
lipid soluble & bound to proteins
-released at a constant rate through time
22
Q
what is an example of something with long half life
A
steroid hormones
23
Q
what has a short half life
A
water-soluble hormones like proteins, epinephrine, & NE
-rapid onset & short duration
24
Q
what are ways hormones are transported (like with what)
A
-unbound
-reversibly bound to plasma proteins
25
are hormones distributed slow or fast
fast- circulate in blood
26
what are examples of lipid soluble hormones
-testosterone, aldosterone
-thyroid hormone (thyroxine)
-prostaglandins
27
what are some water-soluble hormones
-proteins (TSH, growth hormone)
-peptides (insulin, TRH)
-amino acid derivatives (epinephrine)
28
what are the three patterns of hormone secretion
chronic
acute
episodic (cyclic)
29
chronic hormone regulation
maintenance of relatively constant concentration of hormone
30
chronic hormone ex
thyroid hormone
31
acute hormone regulation
big spikes (fight or flight)
32
acute hormone ex
epinephrine in stress
33
episodic hormone regulation
every once in a while
34
episodic hormone ex
female reproductive hormones (once a month cycle thing)
35
T/F most hormones are secreted at a constant rate
F
-they fluctuate in a homeostatic range
36
what three types of stimuli regulate hormone release
1. humoral stimuli
2. neural stimuli
4. hormonal stimuli
37
are most hormones positive or negative feedback
negative feedback
38
what are humoral stimuli
blood borne molecules (glucose, calciu, sodium) that stimulate release of a hormone in response to the molecules concentration level in the blood
-action of a non-hormone substance on an endocrine gland
39
what are neural stimuli
AP, neurons release a neurotransmitter into the synapse with the cells that produce the hormone
40
neural stimuli ex of exercise response
sympathetic n - adrenal gland - epinephrine - norepinephrine = increased HR & blood flow
41
what is the most common stimuli
hormonal
42
what happens with hormonal stimuli
one endocrine gland hormone (or neurohormone) stimulates the secretion of another endocrine gland
-TSH from pituitary - thyroid hormone from thyroid gland
43
what is the area called where the molecule binds the hormone
binding site or receptor site
44
is the receptor site specific or not
it is specific
45
what is the exception to a specific receptor site
epinephrine
46
what happens when a hormone binds a molecule
you get a response by the target cell
47
how often are receptor molecules degraded & replaced
on a regular basis
-changing the number of receptors ensures an optimal target tissue response
48
what happens with down regulation
desensitization occurs
-its when the rate at which receptors are synthesized decreases in some cells after cells are exposed to a hormone
-the combo of hormones & receptors can increase the rate at which receptor molecules are degraded & this happens by increased phagocytosis by the cell
49
what is down-regulation?
desensitization that occurs when cells are exposed to a hormone
50
what happens to receptor synthesis during down-regulation?
the rate at which receptors are synthesized decreases
51
what causes cells to decrease receptor synthesis?
exposure to a hormone
52
what is up regulation
increase in synthesis of receptors, this increased sensitivity to the hormone (since there are more receptors to bind it)
53
what cellular process increases degradation of receptors during down-regulation?
increased phagocytosis by the cell
54
what is an example of up regulation
FSH stimulates an increase in receptor synthesis of LH receptors in ovary cells, which increases ovary cell sensitivity to LH resulting in ovulation
55
which is not a class of hormone receptor
a. membrane bound receptor
b. plasma binding protein
c. intracellular receptor
b. plasma binding protein
56
what are the types of hormone receptors
membrane-bound receptors
nuclear receptors
57
what type of hormones bind to membrane-bound receptors
water-soluble
58
how do water soluble hormones enter the blood stream
as free hormones
59
what type of hormones bind to nuclear receptors
lipid soluble
60
what types of molecules are lipid-soluble hormones?
lipid soluble, relatively small, pass through plasma membrane
61
what are examples of things that all bind to nuclear receptors
-steroid hormones, thyroid hormones
-(testosterone, progesterone, estrogen, cortisol, aldosterone)
62
after entering the cell, what can lipid-soluble hormones react with in the cytoplasm?
they can react with enzymes in the cytoplasm
63
after entering the cell, what can lipid-soluble hormones react with in the nucleus?
they can react with DNA
64
what does reacting with DNA allow lipid-soluble hormones to regulate?
the transcription of genes in the target tissue.
65
after entering the cell, what two things can lipid-soluble hormones react with?
enzymes in the cytoplasm or DNA in the nucleus
66
why do water-soluble hormones need membrane-bound receptors?
bc they are polar & cannot pass through the PM
67
where on the cell do membrane-bound receptors sit?
on the plasma membrane
68
what type of proteins is the receptor on for membrane bound receptors
integral proteins
69
what type of hormones use membrane bound receptors
-water-soluble
-ones with large molecular weight (large proteins, glycoproteins, polypeptides)
-a few smaller molecules (Ep & NE)
70
where are receptor proteins found for nuclear receptors
cytoplasm or nucleus
71
what happens when hormones bind with an intracellular receptor
1. A hormone enters the cell and binds to its intracellular receptor.
2. The hormone + receptor form a receptor-hormone complex.
3. This complex goes to the DNA and attaches to a hormone response element.
4. This tells the DNA to start making mRNA (transcription).
5. The mRNA goes to the ribosome where it is translated into a protein.
72
why is there a latent period in nuclear receptor actions
because the cell needs time to produce mRNA to get a protein
-it may take several hours for a target cell to produce a new protein
73
what stops the process of nuclear action
the receptor-hormone complex eventually breaks down, which ends the hormone’s effect
74
what are the hormones that bind to membrane bound receptors
proteins, peptides, & some amino acid derivatives like ep & NE
75
what are the two results when a hormone binds to a receptor protein in membrane bound receptors
1. alters the activity of G proteins that causes the production of the intracellular mediator: cAMP
2. alters the activity of intracellular enzymes (nitric oxide, cyclic GMP, & Ca2+ ions)
76
what do g proteins interact with
adenylate cyclase
77
what part of the g protein can alter the activity of enzymes inside the cell
activated alpha subunits
78
what receptors does glucagon use
-glucagon binds to membrane-bound receptors on liver cells
-these receptors work through G proteins
79
what happens when glucagon binds?
1. glucagon attaches to its receptor on the liver cell membrane
2. this activates the alpha subunit of the G protein
3. the alpha subunit then binds to adenylate cyclase and turns it on
4. adenylate cyclase produces cAMP (a second messenger)
80
what does cAMP do
1. cAMP activates protein kinase enzymes
2. these protein kinases phosphorylate (turn on) enzymes.
3. those enzymes break down glycogen → glucose
4. the glucose is released from the liver into the bloodstream.
81
what are the other intracellular mediators that g proteins interact with
diacylglycerol & inositol triphosphate (IP3)
82
what does DAG (diacylglycerol) regulate
protein kinases & those that synthesize prostaglandins which results in contraction of smooth muscle
83
what does IP3 cause in the cell
an increase of Ca2+ in the cytoplasm which results in contraction of smooth muscle
84
what effect do prostaglandins have on smooth muscle?
cause contraction of smooth muscle
85
what regulates prostaglandins
DAG
86
which second messenger increases Ca²⁺ levels in the cytoplasm?
IP3
87
what hormone binds to membrane receptors on kidney cells to activate the cGMP pathway?
atrial natriuretic hormone
88
what enzyme is activated when atrial natriuretic hormone binds to its kidney cell receptor?
guanylate cyclase
89
guanylate cyclase converts GTP into what second messenger?
cGMP
90
what does cGMP activate in kidney cells?
enzymes that increase Na+ & water excretion
91
what enzyme breaks down cGMP and inactivates it?
phosphodiesterase
92
when cGMP is inactivated, what molecule is it converted into?
GMP
93
what hormone binds to a receptor that phosphorylates proteins to allow glucose and amino acids into cells?
insulin
94
what effect does insulin receptor activation have on intracellular proteins?
it causes phosphorylation of proteins
95
what does phosphorylation of proteins by the insulin receptor allow?
glucose and amino acid entry into cells
a&p
flashcards
Decks in class (21)
# Cards
-
chapter 169
-
a & p lab one40
-
chapter 262
-
chapter 3159
-
a + p lab 233
-
chapter 4184
-
chapter 5149
-
chapter 6144
-
a&p lab exam26
-
chapter 7142
-
chapter 9 (& some of 10)210
-
chapter 11219
-
chapter 12145
-
lab exam46
-
chapter 13126
-
chapter 15285
-
chapter 1694
-
chapter 1795
-
lab exam18
-
exam 6 q16
-
chapter 18107
