Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MED 310A > endocrine > Flashcards

endocrine Flashcards

1
Q

what does the endocrine system do?

A

Integration and coordination with hormones in response to stress, the body’s internal environment, metabolism, growth and development and reproduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is homeostasis?

A

the ability to regulate its internal conditions typical using feedback systems to minimize variation regardless of external environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are hormones?

A

molecules, secreted by endocrine cells into circulating blood, that act on cells that express their specific receptors
Some molecules are both hormones and neurotransmitters, both bind with specific receptors
Hormones are very cell specific.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is an autocrine cell?

A

receptor on its own surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is a paracrine cell?

A

cell next door so it doesn’t go into blood just the matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is a negative feedback loop?

A

accomplished what’s needed and sends a signal to stop producing. Reduces the effect of the stimulus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are the characetristics of a negative feedback loop?

A

Variable
Sensor
Integrator
Effector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is an example of a negative feedback loop?

A

shivering when cold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is a positive feedback loop?

A

ends with an event that will cause something “explosive event”. Increases the effect of the stimulus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is a feed-forward mechanism?

A

anticipatory response that starts a feedback loop in anticipation of a change about to occur. Usually a reflex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the characteristics of steroid hormones?

A

Derived from cholesterol
Lipid soluble
Not stored
Target = inside cell
Transported in blood bound to plasma proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the caracteristics of tyrosine hormones (general)?

A

Derived from tyrosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the 2 types of tyrosine hormones?

A

catecholamines and thyroid hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the characteristics of catecholamines?

A

In cytosol
Stored in chromaffin granules
Transported through blood half bound to plasma proteins
Target = surface of cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the characteristics of thyroid hormones?

A

n colloid
Stored in colloid
Transported through blood mostly bound to plasma proteins
Target = inside cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

describe the mecahnism of the cAMP second messanger system for hydrophilic hormones;

A

Binding of messenger to receptor activated G protein - activates adenylyl cyclase
Adenylyl converts ATP to cAMP
cAMP activated protein kinase A
Protein kinase A phosphorylates inactive target protein
Cellular response initiated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

describe the mechanism of the calcium ion mechanism for hydrophilic hormones:

A

Binding of messenger to receptor activated G protein - activates phospholipase C
Phospholipase C converts PIP2 to IP3 and DAG
IP3 can;
Mobilize intracellular Ca2 to activate calmodulin which creates a complex. The complex activates CaM kinase which phosphorylates inactive target protein to activate it
DAG activates protein kinase C which phosphorylates inactive target protein to activate it which initiates response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

every level of a second messenger does what?

A

amplifies the response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the sella turcica?

A

protective pocket on the sphenoid bone for the pituitary gland. Shaped like a saddle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

how many lobes does the pituitary have and what are they?

A

2
anterior
posterior

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the only thing anterior and posterior pituitary have is common?

A

location

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

describe the neural pathway of the posterior pituitary;

A

1: the hormone is made and packaged in cell body of neuron
2: vesicles are transported down the cell
3: vesicles containing hormone are stored in posterior pituitary
4: hormones are released into blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are 2 hormones of the posterior pituitary?

A

oxytocin and ADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what are the 2 most well known events oxytocin is involved in?

A

breastfeeding and childbirth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

describe the feedback mechanism for birth;

A

Signals from cervix (stretch) - oxytocin release - uterine smooth muscle contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

describe the feedback loop for breastfeding;

A

ignals induced by suckling - oxytocin release - mammary gland smooth muscle contractions to expel milk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what else releases oxytocin?

A

orgasms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

describe the role of the hypothalamus for the endocrine system;

A

Site of interaction between nervous and endocrine
Many interconnections with other parts of the brain
Emotions and stresses affect endocrine function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what does ADH control?

A

body fluid volume and concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what does ADH target?

A

kidney and smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what does ADH do in the kidney?

A

reduce urinary output and conserve water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what does ADH do at smooth muscle?

A

causes vasoconstriction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

how does ADH limit urine production?

A

Increases the permeability of renal collecting tubule cells to water thus more water will be reabsorbed in kidneys and less urine produced. Mediated by binding to specific receptors
ADH binds, ATP is transformed into cAMP which increases the permeability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what does the concentration of ADH rise in response to?

A

increased osmolarity in the ECF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what is one key factor that ADH does other than maintaining concentration and volume?

A

makes you thirsty

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

desrcribe how high osmolarity in the ECF triggers secretion of ADH;

A

hypothalamic osmoreceptor neurons (lie outside the BBB) detect the changes. High osmolarity causes outside cells to shrink and induces ADH secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

describe how low blood volume induces secretion of ADH;

A

ocated in low pressure, complaint vessels that accommodate blood volume changes and buffer arterial pressure changes. Sensory nerve endings detect the amount of “stretch” and signal PVN and SON. decreased stretch causes ADH to recover the fluid volume.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

describe the osmoreceptor loop;

A

Variable: increased ECF osmolarity
Sensor: osmoreceptors in hypothalamus
Integrator: SON and PVN nuclei in hypothalamus - increased ADH
Effector: kidney collecting tubule - increased water reabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

describe the stretch receptor loop;

A

Variable: decreased blood volume
Sensor: stretch receptor neurons around large vein and cardiac atria
Integrator: SON and PVN in hypothalamus - increased ADH
Effector: kidney collecting tubule - increased water reabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

why does alcohol make you thirsty?

A

inhibits ADH but as alcohol is disposed of in the system it increases dehydration to make you secrete more ADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

what is the blood brain barrier?

A

Specialized endothelial with tight junctions strictly control environmental exposure and protect the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

where is the blood brain barrier lackinh?

A

where hormones are intended for entry to circulation
where neurons need to respond to stimuli from circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

what hormones do the anterior pituitary produce?

A

TSH, ACTH, PROLACTIN, GH, LH and FSH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

what are the “trophs” and what do they produce?

A

Somatotropes: produce GH
Lactotrophs: produce prolactin
thyrotrophs: produce TSH
Gonadotrophs: produce LH and FSH
Corticotrophs: produce ACTH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

describe the feedback mechanism of the hypothalamic-hyposeall portal system;

A

Hormonal and neural input hit the hypothalamic neurosecretory neuron which secretes hormone 1 which goes through a short portal system
The anterior pituitary is activated from hormone 1 to secrete hormone 2 which goes into systemic circulation
Hormone 2 activates the target endocrine gland which secretes hormone 3 before being sent into general circulation
Finally elicits the physiological effect on target cells
Hormone 3 has a negative effect on the anterior pituitary and hypothalamus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

if hormone 1 is deficient in the hypothalamic-hypophyseal portal system what will happen to 2 and 3?

A

they will also be low and the loop will be reduced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

describe what hormone 1 is in the hypothalamic-hypophyseal portal system;

A

hypothalamic releasing hormones
Stimulate release of a specific hormone from cells of anterior pituitary
Thyrotropin releasing hormone (TRH)
Corticotropin releasing hormone (CRH)
Growth hormone releasing hormone (GHRH)
Prolactin releasing hormone (PRH)
Gonadotropin releasing hormone (GNRH)
Inhibiting hormones: prolactin inhibiting hormone (dopamine) and growth hormone inhibiting hormone (GHIH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

describe what hormone 2 is in the hypothalamic-hypophyseal portal system;

A

glycoprotein family, POMC family or GH/Prolactin family.
Glycoprotein: hydrophilic, produced and stored in anterior pituitary cells (gonadotrophs or thyrotrophs). FSH and LH (gonadal target. Stimulate follicle development and spermatogenesis), TSH (acts on thyroid to stimulate secretion of thyroid hormones)
POMC: CRH from hypothalamus stimulates production of POMC by corticotrophs. Here, the large POMC glycoprotein pro-hormone is cleaved to produce; ACTH, beta-endorphins and gamma-lipotropin
GH/prolactin: proteins. Prolactin stimulates milk production.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

describe the hypothalamic-hypophyseal portal vascual system;

A

Neurosecretory neurons in hypothalamus secretes releasing and inhibiting hormones into portal system
Goes through the hypothalamic-hypophyseal portal
Endocrine cells of anterior pituitary secrete anterior pituitary hormones into systemic blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

what is the carcadian rhythm?

A

hypothalamic releasing hormones, their anterior pituitary hormones and target cell hormones exhibit circadian rhythms. Prolactin is the only exception. Arise from intrinsic neural oscillators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

what are the characteristics of the carcadian rhythm?

A

1 major peak/24 hrs. Related to sleep/wake cycle. Each anterior pituitary hormone peaks at different times. Endocrine activity of target organs reflects the oscillation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

where is cortisol produced and when does it peak?

A

produced in the adrenal cortex by ACTH. peaks first thing in the morning.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

what does ACTH do?

A

targets adrenal gland cortex and modulates secretion of adrenal cortex hormones; aldosterone, cortisol and androgens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

what are the characteristics of growth hormone?

A

Increased lipolysis, protein synthesis, use of fatty acids, collagen synthesis, cartilage growth
Promotion of hypertrophy and hyperplasia
Decreased glycogen synthesis and glucose use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

what is the epiphyseal plate?

A

zone for bone growth. Thickens during growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

what are the major inputs for the growth hormone feed back loop?

A

exercise, stress, low blood glucose, diurnal rhythm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

what are the minor inputs for the growth hormone feedback loop?

A

high blood amino acids, low blood fatty acids
Ghrelin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

describe the feedback loop for growth hormone;

A

Go to the hypothalamus to produce GHIH and GHRH
They activate the anterior pituitary somatotroph that releases GH
It can go to the liver t0 make IGF1 and promote actions related to growth
Or it can be used for metabolic actions unrelated to growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

how is secretionof growth hormone stimulated?

A

Stress
Exercise
Hypoglycemia
Amino acids
First 2 hours of deep sleep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

what is gigantism?

A

Abnormally large growth due to excess growth hormone during childhood before closure of growth plates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

what is acromegaly?

A

Over secretion of GH after growth plates have closed. Height unchanged but thicker mature bones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

what is turners syndrome?

A

Females
Have short stature, GH is recommended at puberty

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

what is pituitary dwarfism?

A

GHRH, GH or IGF 1 deficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

what is laron dwarfism?

A

Unresponsive GH receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

what is cretinism?

A

Hypothyroidism
Thyroid hormones are permissible for action of GH
Poor long bone growth as a result of thyroid hormone insufficiency.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

what is achondroplasia?

A

Gene defect for cartilage FGF receptors impairs bone ossification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

what does the medualla of the adrenal gland arise from?

A

ectoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

what does the cortex of the adrenal gland arise from?

A

mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

in the adrenal cortex, what parts secret cortisol and androgens?

A

fasciculata and ZFR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

what type of hormones are adrenal cortex hormones?

A

cholesterol derived

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

how is cholesterol transported through the blood?

A

as LDL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

what receptor do androgens bind to?

A

androgen receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

what receptor does cotrisol bind to?

A

glucocorticoid receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

what receptor does aldosterone bind to?

A

mineralocorticoid receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

what is the rate-limiting SCC enzyme induced by?

A

angiotensin II or elevated plasma potassium in the outer zone
ACTH in the middle zone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

describe what ATCH does in the 3 zones of the adrenal cortex;

A

stimulates and maintains cellular growth
up regulates LDL receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

what does too much ACTH cause?

A

hypertrophy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

what does too little ACTH cause?

A

atrophy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

what are the biological effects of cortisol?

A

carb, proteib and fat intermediary metabolism
protects during acute stress
anti-inflammatory and immunosuppressive
permissive actions for other hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

what are the metabolic effects of cortisol?

A

raises blood glucose (gluconeogenesis)
raises blood amino acids
raises blood fatty acid levels

83
Q

how is cortisol protective during stress?

A

stress stimulates CRH/ACTH/cortisol secretion
metabolic actions increase “raw materials” needed to respond to stress

84
Q

how does cortisol have anti-inflammatory and immunosuppressive effects?

A

limits immune response
suppresses all steps in inflammation
destroys lymphocytes and reduces antibody production

85
Q

what is the effect of exogenous corticosteroids on the ACTH feedback loop?

A

inhibits CRH which is at the top if the loop therefore it will inhibit the ones that follow

86
Q

in the absence of cortisol what happens to the effectiveness of other hormones?

A

they are less effective

87
Q

what is cushing’s syndrome?

A

hypersecretion of cortisol;
excessive CRH or ACTH
possible ACTH secretibg tumor elsewhere in the body
adrenal cortex tumors that secrete cortisol without ACTH

high blood glucose and protein catabolism
fat redistribution to throax and abdomen
moon-face

88
Q

what is adrenogenital syndrome?

A

sex steroid hypersecretion;
steroid production in ideoendent from ACTH control

newborn females - sex reversal
mature women - masculinization
young males - precocious puberty

89
Q

what is addisons disease?

A

adrenocortical insufficiency ;
adrenal cortex being destroyed by autoimmune
lack of adrenal hormone production from level of hypothalamus or anterior pituitary

90
Q

what autonomic nervous system component is the adrenal medulla a modified component of?

A

sympathetic

91
Q

describe the synthesis of catecholamines;

A

tyrosine - DOPA (by tyrosine hydroxylase) - dopamine - 20% noepi, 80% epi (by transferase enzyme induced by cortisol)

92
Q

are catecholamines essential for life?

A

no

93
Q

aside from the stress responses from the ANS what stress responses are specific to the endocrine system?

A

increased secretion of cortisol, ADH, aldosterone, glucagon and growth hormone

94
Q

what is the role of cortisol during stress?

A

increases metabolic fuels
permissive for catecholamine stimulated vasoconstriction
induces enzyme roduction of epi

95
Q

what is the role of ADH and aldosterone during stress?

A

retention of sodium and water to protect ECF and blooc volume

96
Q

what is the role of glucagon during stress?

A

opposes effects of insulin to increase blood glucose

97
Q

what is synergism?

A

the interaction or cooperation of two or more organizations, substances, or other agents to produce a combined effect greater than the sum of their separate effects.

98
Q

describe the HPA axis:

A

stress and dinural stimulate the hypothalamus to released CRH which activates the anterior pituitary to released ACTH which stimulates the adrenal cortex to release cortisol

99
Q

where are serum binding proteins primarily produced?

A

liver

100
Q

what is serum albumin?

A

a large plasma protein present in high concentration

101
Q

which has a longer molecule life, peptide or lipophilic hormones?

A

lipophilic

102
Q

where is the thyroid gland located?

A

in the neck, below chin

103
Q

how many thyroid hormones are there and what are they?

A

2
T3 and T4

104
Q

how must iodine be obtained?

A

through diet

105
Q

describe the synthesis of thyroid hormones;

A

1: follicular cell synthesizes enzymes and thyroglobulin for colloid
2: I is co-transported into the cell with Na and transported into the colloid
3: thyroid peroxidase oxidizes iodine ions, MITS and DITS couple to form T3 and T4
4: thyroglobulin is taken back into the cell
5: intracellular enzymes separate T3 and T4 to form protein

106
Q

what enzyme oxidizes iodine ions so they are incorporated into thyroglobulin?

A

thyroid oxidase

107
Q

what 2 tyrosine moieties couple to make T3 and T4?

A

MITS and DITS

108
Q

is thyroid binding with proteins reversible or irreversible?

A

reversible

109
Q

how is T4 converted to T3?

A

deionation in liver and kidneys

110
Q

how much circulating T3 has been converted from T4?

A

80%

111
Q

which is more bioactive, T3 or T4?

A

T3 - principal thyroid hormone

112
Q

what is every step of the thyroid hormone loop controlled by?

A

TSH

113
Q

how is TSH production controlled?

A

by hypothalamic TRH (thyrotropin releasing)

114
Q

describe the feedback loop of thyroid hormone production;

A

stress/cold in infants signals the hypothalamus to produce TRH which signals the anterior pituitary to release TSH which signals they thyroid gland to make thyroid hormone

115
Q

what does a deficiency of TSH cause?

A

atrophy of the thyroid gland

116
Q

what does excess TSH do?

A

causes hypertrophy and hyperplasia of cells

117
Q

what is an enlarged thyroid called?

A

goiter

118
Q

what is the bioacitvity of thyroid hormones?

A

metabolism
growth and development
nervous system development and function

119
Q

what is basal metabolic rate

A

an estimate of an individuals lowest energy expenditure required to maintain vital functions

120
Q

what is the net effect of normal amounts of thyroid hormones?

A

anabolic

121
Q

what is the net effect of pathologically high amount of thyroid hormones?

A

catabolic

122
Q

thyroid hormone deficient children show…

A

slowed growth

123
Q

what is the effect of thyroid hormone on nervous system function?

A

increases sympathetic activity
increases catecholamine receptor expression
increases speed of nervous reflexes

124
Q

what is hypothyroidism?

A

low secretion of thyroid hormone

125
Q

what is hyperthyroidism?

A

excess secretion of thyroid hormone

126
Q

what can cause hypothyroidism?

A

failure of thyroid gland
failure of hypothalamus or anterior pituitary
lack of iodine

127
Q

waht is caused by hypothyroidism?

A

myxedema

128
Q

what causes hyperthyroidism?

A

autoimmune disease (graves) in which TSI stimulates TSH receptors
thyroid tumor secreting thyroid hormones
excess secretion of TRH or TSH by hypothalamus or anterior pituitary

129
Q

what is caused by hyperthyroidism?

A

bulging eyes (exophthalmos)

130
Q

what causes goiter?

A

hypothyroidism due to lack of iodine
hyperthyroidism due to excess TRH/TSH

131
Q

why is calcium homeostasis essential?

A

bones and teeth
all cells
nerve and muscle function
blood clotting

132
Q

what are the 3 hormones responsible for calcium homeostasis?

A

oarathyroid hormone
calcitonin
vitamin D

133
Q

how is calcium regulated in the ECF?

A

exchange between bone and ECF
renal excretion

134
Q

what type of receptor do the cheif cells in the parathyroid have?

A

calcium ion sensing

135
Q

what type of hormone is PTH?

A

peptide

136
Q

what type of feedback loop is PTH controlled by?

A

negative

137
Q

what does PTH act on?

A

bones, kidneys and GI

138
Q

what are osteoblasts?

A

create new bone by secreting organic matrix and mineralizing it with calcium phosphate crystals

139
Q

what are osteocytes?

A

arise from entombed osteoblasts. involved in calcium regulation but do not create bone

140
Q

what are osteoclasts?

A

dissolve bone by solubilizing the crystals

141
Q

what does PTH stimulate?

A

movement of ionized ca2 from bone to ECF
bone dissolvinf activity of osteoclasts
tips bone remodeling in favour of resorption

142
Q

what is fast exchange associated with for PTH?

A

osteocytic-osteoblactic bone membrnae

143
Q

what is slow exchange associated with for PTH?

A

dissolution of the bone by osteoclasts

144
Q

what do osteoblasts secrete?

A

RANKL (decrease bone mass) and OPG (increase bone mass)

145
Q

what is the effect of PTH on the kidneys?

A

increase renal reabsorption of calcium and increase excretion of phosphate

146
Q

what is the feedback loop associated with PTH?

A

lowered plasma Ca2 stimulates the parathyroid to produce PTH which signals the KIdney to increase renal tubular Ca reabsorption and decrease urinary excretion of Ca, and also signals the bone to mobilize Ca2

147
Q

what type of effect does calcitonin have on bone remodeling?

A

an opposite effect to PTH

148
Q

what type of hormone is calcitonin?

A

peptide

149
Q

what is the feedback mechanism for calcitonin;

A

an increase in plasma Ca2 signals thyroid C cells to produce calcitonin which will decrease plasma Ca2

150
Q

how is vitamin D derived?

A

from skin by action of sunlight and from some foods

151
Q

what type of hormone is vitamin D?

A

steroid

152
Q

how is vitamin D activated?

A

by addition of 2 hydroxyl groups
1st in liver
2nd in kidneys

153
Q

how is kidney hydroxylation enzyme stimulated?

A

PTH
low plasma ionized calcium
low plasma ionized phosphate
prolactin

154
Q

when plasma ionized calcium is high, renal hydroxylation produces…

A

an inactive form of vitamin D3

155
Q

what are the effects of activated vitamin D3?

A

increases total body calcium
increases ECF ionized calcium

156
Q

what is hypoparathyroidism?

A

caused by autoimmune disease or physical damage to glad

low PTH = low plasma Ca2
causes increased neuromuscular excitability
paresthesia
tetany

157
Q

what is hyperparathyroidism?

A

1: hypersecreting parathyroid tumor
hypercalcemia
depressed muscle and nerve excitability
increased fracture risk
risk of kidney stones

2: chronic renal disease or Vit D deficiency causing hypocalcemia
impairs GI absorption of calcium
bone demineralization
kids = rickets
adults = osteomalacia

158
Q

what affects vitamin D profuction?

A

skin pigmentation

159
Q

what risks are associated with vitamin D deficiency?

A

risk of cancer
cardiovascular disease
autoimmune disease
MS
osteoporosis

160
Q

what is osteoporosis?

A

brittle bone disease
bone resorption is greater than formation

161
Q

what percent of the pancrease is endocrine?

A

2%

162
Q

what hormones are secreted by the islets of langerhans?

A

beta cells (insulin and amylin)
alpha cells (glucagon)
D cells (GHIH)
PP cells (pancreatic polypeptide)

163
Q

what is the role of insulin?

A

stimulates uptake and storage of energy substrates

164
Q

what is the role of glucagon?

A

stimulates production of glucose by the liver

165
Q

waht is the function of somatostatin?

A

inhibition of exocrine and endoccrine pancreatic secretion

166
Q

what is the function of pancreatic polypeptide?

A

inhibition of exocrine pancreatic secretion

167
Q

what is the role of pancreatic hormones?

A

provide constant supply of glucose to CNS

168
Q

what are the absorptive and postabsorptive states?

A

fed and fasted states, respectively

169
Q

what is the most significant regulted variable?

A

blood glucose concentration

170
Q

insulin is dominant in what state?

A

fed

171
Q

glucagon is dominant in what state?

A

fasted

172
Q

what other factors influence insulin secretion?

A

increase in blood amino acid level
entry of glucose into small intestine (stimulates GIP and GLP)
increase in parasympathetic activity

173
Q

what do glucose transporters do?

A

accomplish passive facilitated diffusion of glucose across cellular membranes

174
Q

which glucose transporter is insulin dependent?

A

GLUT-4

175
Q

is insulin needed in exercising muscle?

A

no

176
Q

is insulin needed for glucose uptake by brain or liver?

A

no

177
Q

what decreases affinity of receptors?

A

excess glucocorticoids

178
Q

what down regulates receptors?

A

chronically high insulin

179
Q

if the affinity of receptors is decreased and receptors are downregulated, what is the result?

A

insulin resistance

180
Q

what upregulates receptors?

A

starvation

181
Q

what are the major effects of insulin on carb metabolism?

A

increase in glycogenesis in skeletal muscle and liver
decrease hepatic gluconeogenesis
increased glucose upatke by fat cells and resting skeletal muscle

182
Q

how is insulin abused by athletes?

A

inject insulin and eat high sugar foods to increase glycogen storage

183
Q

what are the major effects of insulin on fat metabolism?

A

increase in transport of fatty acids into fat cells
increase of TAG synthesis
activates enzymes that catalyze synthesis of fatty acids from glucose - inhibits lipolysis

184
Q

what are the effects of insulin on protein metabolism?

A

increase transport of blood amino acids
increase protein synthesis
inhibits protein degradation

185
Q

what is the second messenger system for glucagon?

A

cAMP

186
Q

what is hypoglycemia?

A

hyper-secretion of insulin

beta cell tumor
overdose of insulin

187
Q

what is diabetes mellitus?

A

under secretion or resistance to insulin

188
Q

what is type 1 diabetes?

A

autoimmune destruction of beta cells usually in children

189
Q

what is diabetes insipidus associated with?

A

ADH deficiency

190
Q

what is A1C?

A

a measure of glycosylation state of hemoglobin

191
Q

for non-diabetics what is an average A1C result?

A

5%

192
Q

what can uncontrolled glucose usually cause?

A

metabolic disease

193
Q

what is gestational diabetes?

A

glucose intolerance with onset or first recognition during pregnancy

194
Q

what are the risks associated with gestational diabetes?

A

fetal malformation, macrosomia, metabolic complications

195
Q

what is type 2 diabetes?

A

impaired insulin secretion or resistance

196
Q

what does chronic overeating influence?

A

high blood glucose, high insulin secretion
down-regulates insulin receptors

197
Q

what do TZDs do for type 2 diabetes?

A

improve A1C and glucose control
increased fat storage. reducing circulating fatty acids, blood glucose, hyperinsulinemia

198
Q

what are the competing behavioural states?

A

appetite and satiety

199
Q

what is satiety?

A

the feeling of fullness

200
Q

where are satiety and appetite controlled?

A

hypothalamus

201
Q

what is the glucostatic theory?

A

blood glucose levels ultimately control the feeding and satiety centers

202
Q

what is the lipostatic theory?

A

the level of body fat regulates the feeding and satiety centerss

203
Q

where is leptin produced?

A

adipose tissue

204
Q

when does ghrelin increase?

A

in response to decreased body fat and increased muscle mass

205
Q

what characterizes metabolic syndrome?

A

high blood glucose
high blood pressure
high TAG
low HDL
obesity of abdominal area

MED 310A (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions