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BIO 207- Human Physiology > Exam 4- Chapter 11 > Flashcards

Exam 4- Chapter 11 Flashcards

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1
Q

Describe the structure of endocrine glands and where the secrete their hormones.

A

ductless and secrete hormones into bloodstream

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2
Q

Where do the hormones of endocrine glands travel to?

A

Hormones travel to target cells that contain receptor proteins for it

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3
Q

Neurohormones

A

secreted into blood by specialized neurons

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4
Q

Hormones affect _____ of targets.

A

metabolism

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5
Q

What are the 4 types of hormones?

A
  1. Amine hormones
  2. Polypeptide and protein hormones
  3. Glycoproteins
  4. Steroids
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6
Q

What are amine hormones derived from?

A

tyrosine or tryptophan

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7
Q

What do amine hormones include?

A
  1. NE
  2. Epi
  3. thyroxine
  4. melatonin
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8
Q

What are polypeptide and protein hormones chains of?

A

amino acids

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9
Q

What do polypeptide and protein hormones include?

A

Include ADH, GH, insulin, oxytocin, glucagon, ACTH, PTH

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10
Q

What do glycoprotiens include?

A

LH, FSH, TSH

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11
Q

What are steroids derived from?

A

lipids derived from cholesterol

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12
Q

What do steroids include?

A
  1. testosterone
  2. estrogen
  3. progesterone
  4. alsoterone
  5. cortisol
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13
Q

____ and ____ hormones are lipids.

A
  1. Steroid

2. thyroid

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14
Q

Since steroids and thyroid hormones are lipids what does this allow for?

A

Can diffuse into target cells

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15
Q

What are the two major thyroid hormones?

A
  1. Thyroxine (T4)

2. Triiodothyronine (T3)

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16
Q

Prohormones/Give example.

A

precursors of hormones/proinsulin

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17
Q

Prehormones/Give example.

A

precursors of prohormones/preproinsulin

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18
Q
  1. Some hormones are inactive until activated by ___ ____.

2. Give an example of this

A
  1. Target Cells

2. Thyroxine (T4) is inactive until converted to T3 in target cells

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19
Q

Both NS and endocrine system use chemicals to communicate. Difference between NTs and hormones is what?

A

Difference between NTs and hormones is transport in blood and more diversity of effects in hormone targets

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20
Q

Can some chemicals be used as hormones and NTs?

A

YES

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21
Q

Do targets for NTs have specific receptor proteins?

A

YES

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22
Q

Do targets for hormones have specific receptor proteins?

A

YES

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23
Q

There must be a ___ way to inactivate NTs and Hormones.

A

Rapid

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24
Q

Does a tissue have a specific hormone it responds to?

A

NO; tissue usually responds to # of hormones

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25
Synergistic Hormones.
work together to produce an effect
26
Do synergistic hormones produce a larger effect together or when the individual effects are added together?
Produce a larger effect together than individual effects added together
27
Permissive effect.
enhances responsiveness of a target organ to 2nd hormone
28
Antagonistic hormone.
action of 1 hormone inhibits effect of another
29
Half- Life.
time required for blood level to be reduced by half
30
What is the range of a half-life?
Ranges from mins to hrs for most (days for thyroid hormones)
31
Normal tissue responses are produced only when hormones are in _____ range.
physiological
32
High (pharmacological) doses of hormones can cause # of side effects. Why?
Probably by binding to receptors of different but closely related other hormones
33
What is another name for the priming effect?
Up-regulation
34
What is another name for desensitization?
downregulation
35
When does the Priming effect (upregulation) occur? What does it result in?
1. when a hormone induces more of its own receptors in target cells 2. Results in greater response in target cell
36
When does desensitization (downregulation) occur?
occurs after long exposure to high levels of polypeptide hormone
37
With desensitization (down regulation) what happens with subsequent exposure to the hormone? Why?
1. Subsequent exposure to this hormone produces a lesser response 2. Due to decrease in # of receptors on target
38
Most peptide hormones have pulsatile secretion which ____ ____.
prevents downregulation
39
Target cell receptors show what 3 characteristics for a hormone?
1. specificity 2. high affinity 3. low capacity
40
Where do lipophilic hormones have receptors, and why?
Lipophilic hormones have receptors in target's cytoplasm and/or nucleus because can diffuse thru plasma membrane
41
1. What is the target of lipophilic hormones and what do they affect there? 2. What is this called and how long does it usually take?
1. Their target is the nucleus where they affect transcription 2. Genomic action and takes at least 30 mins
42
Where are the receptors for hydrophilic hormones?
surface of target cell
43
What system to hydrophilic hormones act through and are they fast or slow? What is this called?
1. These act through 2nd messengers; effects are quick | 2. Nongenomic action
44
Even though steroids are lipophilic and enter the target cells, what do some steroids act on?
Some steroids also act on cell surface receptors
45
Generally how do lipid hormones enter the target cell?
1. Lipid hormones travel in blood attached to carrier proteins 2. They dissociate from carriers to pass thru plasma membrane of target
46
What are the receptors for lipid hormones called?
nuclear hormone receptors
47
What do nuclear hormone receptors serve as when bound to hormone ligands? What do they do when this happens?
1. transcription factors | 2. Activate transcription
48
Nuclear hormone receptors constitute a "superfamily", what is this composed of?
1. Steroid family | 2. Thyroid hormone family (which includes vitamin D and retinoic acid)
49
What does the thyroid hormone family include?
vitamin D and retinoic acid
50
What are the 2 domains of nuclear hormone receptors?
1. Ligand (hormone)-binding domain | 2. DNA-binding domains
51
When the hormone binds to the nuclear hormone receptor, what does the receptor then bind to?
hormone-response element (HRE) on DNA located adjacent to target gene
52
What does the HRE consist of?
2 half-sites
53
Mechanisms of Steroid Hormones: | What stimulates the transcription of the target gene? What is this called?
1. 2 ligand-bound receptors have to bind to each HRE | 2. Dimerization
54
Mechanism of Thyroid Hormone Action: | What 2 hormones does the thyroid secrete and what is the percentage of each?
Thyroid secretes 90% T4 (thyroxine) and 10% T3
55
Mechanism of Thyroid Hormone Action: | 99.96% of T4 in blood is bound to carrier protein, what is this carrier protein called?
thyroid binding globulin (TBG)
56
Mechanism of Thyroid Hormone Action: | What can enter the cell?
Only free thyroxine and T3 can enter cells
57
Mechanism of Thyroid Hormone Action: | Protein bound thyroxine serves as a ______.
reservoir
58
Mechanism of Thyroid Hormone Action: | What happens to T4 inside the target cell?
T4 converted to T3 inside target cell
59
Mechanism of Thyroid Hormone Action: | What happens to T3 (and the T4 that was converted into T3) inside the target cell?
T3 binds to receptor protein located in nucleus
60
Mechanism of Thyroid Hormone Action: | Describe what happens after T3 is bound to its receptor.
1. T3 and receptor bind to 1 half-site 2. Other half-site binds retinoic acid 3. Two partners form heterodimer that activates HRE 4. Stimulates transcription of target gene
61
What is different about the mechanism of steroid hormones and thyroid hormones?
Steroid hormones bind to both receptors and then to the half sites while with thyroid hormones, thyroid hormone binds to one with retinoic acid binds to the other.
62
What type of hormones use 2nd messengers?
Water soluble hormones
63
Which receptors do water soluble hormones use, and why?
Water soluble hormones use cell surface receptors because cannot pass through plasma membrane
64
The actions of water soluble hormones are mediated by what?
by 2nd messengers
65
In the mechanism of water soluble hormones what is the extracellular signal? What carries the signal from the receptor to inside the cell?
1. Hormones = extracellular signal | 2. 2nd messengers carry signal from receptor to inside of the cell
66
What are the 3 second messenger systems used with hormones?
1. Adenylate Cyclase-cAMP 2. Phospholipase-C-Ca2+ 3. Tryosine Kinase 2nd messenger system
67
cAMP mediates effects of many ____ and _____ hormones.
1. polypeptide | 2. glycoprotein
68
Describe the mechanism of the Adenylate Cyclase-cAMP 2nd messenger system.
1. Hormone binds to receptor causing dissociation of a G-protein subunit 2. G-protein subunit binds to and activates adenylate cyclase - This converts ATP into cAMP 3. cAMP attaches to inhibitory subunit of protein kinase 4. Inhibitory subunit dissociates, activating protein kinase - This phosphorylates enzymes that produce hormone’s effects
69
What is cAMP inactivated by?
phosphodiesterase
70
Describe the mechanism of the Phospholipase-C-Ca2+ 2nd messenger system.
1. Hormone binds to surface receptor and activates G-protein; which activates phospholipase C 2. Phospholipase C splits a membrane phospholipid into 2nd messengers IP3 and DAG 3. IP3 diffuses through cytoplasm to ER - This causes Ca2+ channels to open 4. Ca2+ diffuses into cytoplasm and binds to and activates calmodulin 5. Ca2+-Calmodulin activates protein kinases which phosphorylate enzymes that produce hormone's effects
71
Which 2nd messenger system does epinephrine act by?
TWO: 1. Adenylate Cyclase-cAMP 2nd messenger system 2. Phospholipase-C-Ca2+ 2nd messenger system
72
What is the Tryosine Kinase 2nd messenger system used by, and what does it cause?
Is used by insulin and many growth factors to cause cellular effects
73
Describe the mechanism of the Tryosine Kinase 2nd messenger system.
- Surface receptor is tyrosine kinase 1. Consists of 2 units that form active dimer when insulin binds 2. Activated tyrosine kinase phosphorylates signaling molecules that induce hormone/growth factor effects
74
What is the surface receptor for the ryosine Kinase 2nd messenger system?
- Surface receptor is tyrosine kinase
75
Insulin stimulates glucose uptake by means of what?
GLUT 4 carrier proteins
76
After insulin binds to tyrosine kinase, and activates the Tryosine Kinase 2nd messenger system what happens?
2nd messengers cause vesicles containing GLUT4 transporters to be inserted into plasma membrane
77
Where is the pituitary gland located?
beneath hypothalamus at base of forebrain
78
How is the pituitary gland divided?
structurally and functionally divided into anterior and posterior lobes
79
The pituitary gland hangs below hypothalamus by the ______.
infundibulum
80
What is the function of the anterior pituitary gland?
Produces own hormones that are controlled by hypothalamus
81
What is the function of the posterior pituitary gland?
Posterior stores and releases hormones made in hypothalamus
82
What hormones does the posterior pituitary gland store/release that were made in the hypothalamus?
1. Oxytocin | 2. Vasopressin (ADH/AVP)
83
How many and what type of hormones does the anterior pituitary gland secrete?
Secretes 6 trophic hormones that maintain size of targets
84
High blood levels of the anterior pituitary hormones cause the target to ____.
hypertrophy (increase volume)
85
Low blood levels of the anterior pituitary hormones cause the target to ____.
atrophy (decrease volume)
86
What are the names of the 6 anterior pituitary hormones?
1. Growth Hormone (GH) 2. Thyroid Stimulating Hormone (TSH) 3. Adrenocorticotrophic Hormone (ACTH) 4. Follicle Stimulating Hormone (FSH) 5. Luteinizing Hormone (LH) 6. Prolactin (PRL)
87
``` What is the function of the: Growth Hormone (GH) ```
1. promotes growth 2. promotes protein synthesis 3. promotes movement of amino acids into cells
88
What is the function of the: | Thyroid Stimulating Hormone (TSH)
stimulates thyroid to produce and secrete: 1. T4 2. T3
89
``` What is the function of the: Adrenocorticotrophic Hormone (ACTH) ```
stimulates adrenal cortex to secrete: 1. cortisol 2. aldosterone
90
What is the function of the: | Follicle Stimulating Hormone (FSH)
1. stimulates growth of ovarian follicles | 2. stimulates sperm production
91
``` What is the function of the: Luteinizing Hormone (LH) ```
1. causes ovulation | 2. causes secretion of testosterone in testes
92
What is the function of the: | Prolactin (PRL)
stimulates milk production by mammary glands
93
What is the release of anterior pituitary hormones controlled by?
1. hypothalamic releasing and inhibiting factors | 2. feedback from levels of target gland hormones
94
Describe how the hypothalamic releasing and inhibiting factors control the anterior pituitary.
1. Releasing and inhibiting hormones from hypothalamus are released from axon endings into capillary bed in median eminence 2. Carried by hypothalamo-hypophyseal portal system directly to another capillary bed in A. Pit. 3. Diffuse into A. Pit. and regulate secretion of its hormones
95
The hypothalamic-pituitary-gonad axis (control system) involves what 3 types of "loops"?
1. Short feedback loop 2. Negative feedback loop 3. Positive feedback loop
96
Describe the short feedback loop of the hypothalamic-pituitary-gonad axis (control system).
retrograde flow of blood and hormones from A. Pit. to hypothalamus inhibits secretion of releasing hormone
97
Describe the negative feedback loop of the hypothalamic-pituitary-gonad axis (control system).
negative feedback of target gland hormones
98
Describe the positive feedback loop of the hypothalamic-pituitary-gonad axis (control system).
during menstrual cycle, estrogen stimulates “LH surge” by positive feedback
99
What input do higher brain centers have in anterior pituitary secretion?
Hypothalamus receives input from higher brain centers that can affect A. Pit. secretion
100
What is an example of higher brain centers having input in anterior pituitary secretion?
emotional states and psychological stress can affect circadian rhythms, menstrual cycle, and adrenal hormones
101
What is the function of Vasopressin (ADH/AVP)?
promotes H2O conservation by kidneys
102
What is the function of oxytocin?
1. Stimulates contractions of uterus during parturition | 2. Stimulates contractions of mammary gland alveoli for milk-ejection reflex
103
What part of the hypothalamus produces ADH?
Supraoptic nuclei of hypothalamus
104
What part of the hypothalamus produces oxytocin?
Paraventricular nuclei of hypothalamus
105
How is ADH/Vasopressin and Oxytocin transported from the hypothalamus to the posterior pituitary?
Both transported along hypothalamo-hypophyseal tract to posterior pituitary
106
What is the release of the posterior pituitary controlled by?
Release controlled in hypothalamus by neuroendocrine reflexes
107
Where do the adrenal glands sit on? What do the adrenal glands structurally consist of?
1. Sit on top of kidneys | 2. Each consists of outer cortex and inner medulla
108
Do the outer cortex and inner medulla of the adrenal cortex arise the same during development?
NO; arise differently during development
109
What 2 hormones does the inner medulla of the adrenal cortex synthesize/secrete (how much % of each)? What is this controlled by?
1. 80% Epinephrine and 20% Norepinephrine | 2. Sympathetic division of ANS
110
What is the adrenal cortex controlled by?
ACTH
111
What does the adrenal cortex secrete?
1. Cortisol 2. Aldosterone 3. Some supplementary sex steroids
112
What is the function of: | Cortisol
inhibits glucose utilization and stimulates gluconeogenesis
113
What is the function of: | Aldosterone
stimulates kidneys to reabsorb Na+ and secrete K+
114
Do the hormonal effects of epinephrine or norepinephrine last longer, and by how much?
Hormonal effects of Epinephrine last 10X longer than Norepinephrine
115
What is the adrenal medulla innervated by?
preganglionic Sympathetic fibers
116
When is the adrenal medulla activated?
"fight or flight" response
117
What does the activation of the adrenal medulla cause?
1. Increased respiratory rate 2. Increased HR and cardiac output 3. General vasoconstriction which increases venous return 4. Glycogenolysis and lipolysis
118
What does stress induce? What does this cause?
1. Stress induces a non-specific response called general adaptation syndrome (GAS) 2. Causes ACTH and cortisol release
119
When stress induces GAS and causes ACTH and corstisol release, what type of feedback loop is this?
Negative feedback loop
120
Chronic stress can induce high levels of cortisol that cause a number of ___ ____.
negative effects
121
What are 4 negative effects that chronic stress and the high levels of cortisol that it induces cause?
1. atrophy of hippocampus (involved in memory) 2. reduced sensitivity of tissues to insulin (insulin resistance) 3. inhibition of vagus nerve activity 4. suppression of growth hormone, thyroid hormone, and gonadotropins
122
Where is thyroid gland located?
just below the larynx
123
What does the thyroid gland secrete, and what is the function of these hormones?
Secretes T4 and T3: 1. Set BMR 2. Needed for growth and development
124
The thyroid gland consist of microscopic ____ ___.
thyroid follicles
125
The thyroid gland consist of microscopic thyroid follicles. 1. What does the outer layer consist of and what is the function? 2. What is the interior filled with?
1. Outer layer is follicle cells that synthesize T4 | 2. Interior filled with colloid, a protein-rich fluid
126
Describe the production and secretion of the thyroid hormones.
1. Iodide (I-) in blood is actively transported into follicles and secreted into colloid 2. In the colloid it is oxidized to iodine (I2) and attached to tyrosines of thyroglobulin 3. TSH stimulates hydrolysis of T4 and T3s from thyroglobulin and then secretion
127
What is thyroglobulin?
A large storage molecule for T4 and T3
128
What exactly does TSH do in the thyroid gland?
TSH stimulates hydrolysis of T4 and T3s from thyroglobulin and then secretion
129
What are 3 diseases of the thyroid?
1. Goiter 2. Hypothyroidism 3. Hyperthyroidism
130
Describe what happens with Goiter (disease of the thyroid).
1. In absence of sufficient dietary iodide, T4 and T3 cannot be made and levels are low 2. Low T4 and T3 don’t provide negative feedback and TSH levels go up 3. Because TSH is a trophic hormone, thyroid gland grows resulting in a goiter
131
People with inadequate T4 and T3 levels are what?
hypothyroid
132
People who are hypothyroid have what?
1. low BMR 2. weight gain 3. lethargy 4. cold intolerance 5. myxedema
133
What is myxedema?
puffy face, hands, feet
134
During fetal development what can hypothyroidism cause?
cretenism (severe mental retardation)
135
Goiters are also produced by what?
Grave's disease
136
What is Grave's disease?
Autoimmune disease where antibodies act like TSH and stimulate thyroid gland to grow and oversecrete = hyperthyroidism
137
What is Grave's disease/Hyperthyroidism characterized by?
1. exopthalmos 2. weight loss 3. heat intolerance 4. irritability 5. high BMR
138
Where are the parathyroid glands located?
embedded in lateral lobes of post. side of thyroid gland
139
What do the parathyroid glands secrete?
Parathyroid hormone (PTH)
140
What is the function of the Parathyroid hormone (PTH)?
Most important hormone for control of blood Ca2+ levels
141
What is the release of the Parathyroid hormone (PTH) stimulated by?
Release stimulated by decreased blood Ca2+
142
What does the Parathyroid hormone (PTH) act on?
Acts on bones, kidney, and intestines to increase blood Ca2+ levels
143
What type of feedback loop does the PTH work on?
negative feedback loop
144
What are the Islets of Langerhans?
Are scattered clusters of endocrine cells in pancreas
145
What type of cells do the Islets of Langerhans contain?
Contain alpha and beta cells
146
What do the alpha cells of the Islets of Langerhans secrete and in response to what?
Alpha cells secrete glucagon in response to low blood glucose
147
When the alpha cells of the Islets of Langerhans secrete glucagon what does this stimulate?
Stimulates glycogenolysis and lipolysis: | which increases blood glucose
148
What do the beta cells of the Islets of Langerhans secrete and in response to what?
insulin in response to high blood glucose
149
Describe the mechanism of the beta cells of the Islets of Langerhans.
1. Beta cells secrete insulin in response to high blood glucose 2. Promotes entry of glucose into cells and conversion of glucose into glycogen and fat 3. Decreases blood glucose
150
Where is the pineal gland located?
basal forebrain near thalamus
151
What does the pineal gland secrete and in response to what?
Secretes melatonin in response to activity of suprachiasmatic nucleus (SCN) of hypothalamus
152
What is the primary timing center for circadian rhythms?
suprachiasmatic nucleus (SCN)
153
How often and by what is the suprachiasmatic nucleus (SCN) reset?
Reset by daily light/dark changes
154
What is melatonin involved in?
aligning physiology with sleep/wake cycle and seasons
155
When is melatonin secreted/inhibited?
Secreted at night and is inhibited by light
156
When is melatonin implicated?
Implicated in jet-lag
157
Which GI tract organs produce hormones?
1. Stomach 2. Small intestine 3. (Pancreas?)
158
What do the hormones of the small intestine act on?
Act on GI tract itself, gallbladder, and pancreas
159
The hormones of the small intestine act in convert with what? What is the function of this?
1. ANS | 2. To coordinate regions of GI tract and pancreatic juice and bile
160
What hormones do the gonads secrete (testes and ovaries)?
steroid hormones: 1. testosterone 2. estrogen 3. progesterone
161
What hormones does the placenta secrete?
1. estrogen 2. progesterone 3. hCG 4. somatomammotropin
162
Autocrine regulators.
produced and act within same tissue of an organ
163
All autocrines control ___ ____in target cells.
gene expression
164
Paracrine regulators.
autocrines that are produced within one tissue and act on different tissue in same organ
165
Autocrines and paracrines include:
1. Cytokines (lymphokines, interleukins) 2. Growth factors (promote growth and cell division) 3. Neutrophins (provides trophic support for normal and regenerating neurons)
166
What are examples of Cytokines?
lymphokines & interleukins
167
What do growth factors do?
promote growth and cell division
168
What is the function of neutrophins?
provides trophic support for normal and regenerating neurons
169
Where are Prostaglandins (PGs) produced?
Are produced in almost every organ
170
What family do Prostaglandins (PGs) belong to? What is everything in this family derived from?
Belong to eicosanoid family -- all derived from arachidonic acid of plasma membrane
171
Prostaglandins (PGs) have a ____ variety of functions.
wide
172
Lists 4 functions of Prostaglandins (PGs).
1. Different PGs may exert antagonistic effects in tissues 2. Promotes inflammatory process of immune system 3. Plays role in ovulation 4. Inhibits gastric secretion in digestive system
173
Different PGs may exert antagonistic effects in tissues. Give 2 examples of this.
1. Some promote smooth muscle contraction and some relaxation 2. Some promote clotting; some inhibit
174
What is involved in PG synthesis?
Cyclooxygenase (COX) 1 and 2
175
Cyclooxygenase (COX) 1 and 2 are targets of a number of what?
inhibitory non-steroidal anti-inflammatory drugs (NSAIDs)
176
Aspirin, indomethacin, ibuprofen inhibit what?
both COX 1 and 2 thereby producing side effects
177
Celebrex and Vioxx inhibit what?
only inhibit COX 2 and thus have few side effects in the gastric mucosa

BIO 207- Human Physiology (13 decks)

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