Brainscape's Knowledge GenomeTM

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


See full index

Physiology > Lecture 11: Introduction to Endocrine > Flashcards

Lecture 11: Introduction to Endocrine Flashcards

1
Q

Is the endocrine system under extrinsic or intrinsic control

A

Extrinsic

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

Endocrinology

A

Study of homeostatic regulation, growth and other activities that hormones accomplish

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

What is a hormone

A

Chemical messenger released from ductless glands or neurons into the bloodstream

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

Hormones are very potent in ___ concentrations

A

Low

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

Describe endocrine signaling

A

Hormone is released from secreting cell into nearby capillary and then travels through larger blood vessels and into capillaries near target and then finally binds to target cells

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

What is the basic order in HP axis

A

CNS input—> hypothalamus—> pituitary—> everything else

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

What are two hormones that are exceptions of the hypothalamic control

A

Insulin (blood sugar) and parathyroid hormone (ca2+)

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

What cells release insulin in response to elevated glucose levels

A

Pancreatic Beta cells

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

What tissues are exclusive to endocrine function

A

Pituitary, thyroid, parathyroid, and adrenal glands

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

What are the three different types of hormones

A

Amines, steroids, peptides

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

What are amines

A

Derived from modification of a single amino acid

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

What are two examples of amine hormones

A

Epinephrine and thyroid hormones

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

Where is epinephrine released from and is it polar vs nonpolar and hydrophilic vs hydrophobic

A

Released from adrenal medulla
Polar and hydrophilic

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

Are thyroid hormones polar vs nonpolar and hydrophilic vs hydrophobic

A

Non-polar and hydrophobic

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

What are peptides

A

Chains of amino acids

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

What hormones are derived as a product of gene expression

A

Peptides

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

Are peptides polar vs nonpolar, hydrophilic vs hydrophobic

A

Polar and hydrophilic

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

What type of hormones are CRH, ACTH, GH, oxytocin, vasopressin, insulin and glucagon

A

Peptide hormones

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

Describe peptide hormone synthesis

A

Peptide hormones are synthesized in nucleus as they are a product of gene expression, then sent to golgi for packaging, packed into secretory vesicles and secreted

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

What is pro-opiomelanocortin (POMC)

A

Precursor peptide to several hormones and signaling molecules

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

What are propeptide convertase

A

Cleaves the pro hormone (POMC) at specific locations at lysine and arginine junctions

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

What are the two propeptide convertase

A

PC1 and PC2

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

PC1 is expressed solely in ____ and produces ____

A

Pituitary corticosteroids and produces ACTH

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

PC2 and PC1 are expressed in _____, producing ______

A

Melanotrophs, producing alpha-MSH, beta-MSH, Beta-endorphin

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

___ and ___ are never produced in same cell type

A

alpha-MSH and ACTH

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

What are the three qualities of steroid hormones

A

Non-polar, lipophilic and made from cholesterol

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

Steroids are synthesized from cholesterol in what parts of body

A

Gonads, adrenal cortex, adipose tissue, placenta, and brain

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

Where is cortisol and aldosterone produced

A

Adrenal cortex

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

Mobilization of cholesterol into cells is mediated by what 3 channels

A

ACTH, ANG II, and K+

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

What 3 things is cholesterol derived from

A
  1. LDL in diet
  2. Hydrolysis of cholesterol esters in vesicles
  3. De novo synthesis of acetyl CoA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are the steps of biosynthesis of steroids in the adrenal cortex

A
  1. Cholesterol is transported to mitochondria and localized by steroidogenic acute regulatory protein (STaR)
  2. Cholesterol is converted to pregenenolone by cholesterol desmolase (CYP11A1), primarily activated by ACTH
  3. Subsequent conversions occur in smooth ER, facilitated by certain enzymes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What primarily activates cholesterol desmolase

A

ACTH

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

All steroids share their initial step of biosynthesis which is

A

Conversion of cholesterol—> pregnenolone

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

What cells respond to hormones

A

Cells with receptor for hormone, if no receptor= no response

35
Q

What are hormone receptors

A

Proteins that bind to the hormone and initiate a cellular repsonse

36
Q

Where in cells are hormone receptors found

A
  1. Cell membranes
  2. Cytoplasm
  3. Nuclei
37
Q

What types of hormones can bind receptors in cell membranes

A

Polar hormones- PEPTIDES and epinephrine

38
Q

What types of hormones can bind receptors in cytoplasm and/or cell nuclei

A

Nonpolar hormones-steroids and thyroid hormones

39
Q

Describe the steps in steroids binding to receptor and producing cellular response

A

Steroids can cross cell membrane (nonpolar) and bind receptor in cytoplasm—> translocated into nucleus where hormone and receptor act as transcription factor to activate or inhibit gene transcription

Biological effect of steroid hormones: gene transcription—> proteins

40
Q

Describe the steps for peptide hormones binding the receptor and producing a cellular response

A

Peptide binds receptor on cell membrane (polar) activates AC-> cAMP—> activate kinases to phosphorylation of an enzyme

Biological effect of peptide hormones: activation of enzymes via phosphorylation

41
Q

What 3 things can stimulate release of hormone

A

Neural stimulus (ex: increase AP)
Another hormone (CRH—>ACTH)
Humoral stimuli- change in solute concentration (ex: BG and insulin)

42
Q

What is the main mechanism by which homeostasis is regulated

A

Negative feedback

43
Q

What is the basic negative feedback loop with HPA axis

A

Hypothalamus (releasing hormones)—-> anterior pituitary (trophic hormones)—> target organs (adrenals, thyroid)—> hormone and that hormone will have negative feedback on hypothalamus

44
Q

What is the ultrashort negative feedback loop

A

Releasing hormone (ex: CRH) inhibiting hypothalamus

45
Q

What is the short negative feedback loop

A

Trophic hormone (ex: ACTH) inhibiting hypothalamus

46
Q

What is the long feedback loop

A

Hormone released from target organs (ex: cortisol) inhibiting anterior pituitary and hypothalamus

47
Q

What pathway connects the hypothalamus and posterior pituitary

A

Neural pathway/neurohyophysis

48
Q

What is the neural pathway

A

Neurons project to neurohyophysis (aka pars nervosa) to release hormones (oxytocin or vasopressin)

49
Q

What pathway connects the hypothalamus and anterior pituitary

A

Anterior pathway

50
Q

What is the anterior pathway

A

Releasing hormones are releasing into portal system (from hypothalamus) to release trophic hormones from anterior pituitary

51
Q

In the HPA axis what is the releasing hormone and what is the trophic hormone

A

Releasing hormone: CRH
Trophic hormone: ACTH

52
Q

Which cell type in the anterior pituitary does CRH act on to stimulate ACTH

A

Corticotropes

53
Q

ATCH targets ___ gland

A

Adrenal

54
Q

What three kinds of hormones are released from the adrenal gland

A
  1. Glucocorticoids (cortisol/cortisterone)
  2. Mineralcorticoids (aldosterone)
  3. Weak androgens (androstenedione, DHEA)
55
Q

Where is CRH released from

A

Paraventricular nucleus in hypothalamus

56
Q

What is the function of CRH in HPA axis

A

Released from PVN and travels to anterior pituitary via portal blood to stimulate corticotropes and release ACTH

57
Q

What are the 3 functions of ACTH in cortisol regulation of HPA axis

A
  1. Inhibit CRH via short feedback loop
  2. Stimulate adrenal growth
  3. Transfers cholesterol to mitochondria and activates cholesterol desmolase (CYR11A1) for steroid synthesis
58
Q

What is the function of cortisol in regulating HPA axis

A

Directly inhibits CRH and ACTH, inhibits ACTH by inhibiting CRH

59
Q

What is the primary effect of cortisol

A

Increase blood glucose by enhancing glucogenesis in the liver

60
Q

How does cortisol impact protein catabolism

A

Increase

61
Q

How does cortisol impact protein synthesis

A

Decreases

62
Q

How does cortisol impact lipolysis of fats

A

Increases

63
Q

What is the diabetogenic effect of cortisol

A

Decreases glucose uptake by tissues, and decreases sensitivity to insulin

Result: increased BG

64
Q

How does cortisol effect cardiovascular tissue

A

Maintains normal BP (over time causes hypertension), upregulates alpha-1 adrenergic receptor, enhances vasoconstriction

65
Q

How does cortisol increase cardiac output

A

Increases ventricular contractions and upregulates alpha-1 adrenergic receptor

66
Q

How does cortisol impact bones

A

Inhibits synthesis of type I collagen, decrease osteoblasts and decrease Ca2+ absorption

67
Q

How does cortisol effect immune function

A

Anti-inflammatory effects, decreases PLA, IL-2, histamine, serotonin

68
Q

How does cortisol effect CT and muscle

A

Inhibits fibroblast proliferation and collagen formation, thin skin, impaired tissue, proteolysis in muscle leading to weakness

69
Q

How does cortisol secretion reflect circadian rhythms

A

Cortisol levels change throughout the day, increase in AM and decrease throughout the day

70
Q

Cortisol levels are ___ during hunger and stress

A

Elevated

71
Q

What is Cushing’s syndrome a result of

A

Due to primary adrenal hyperplasia

72
Q

What are some symptoms in cushing’s syndrome

A

Hyperglycemia, hypertension, increase protein catabolism, muscle wasting central obesity, thin skin, bruising

73
Q

What are ACTH and CORT levels in patient with Cushing’s syndrome

A

ACTH is low, CORT is high

74
Q

What is Cushing’s disease a result of

A

Due to secondary excess ACTH from pituitary or ACTH secreting cells in the lungs

75
Q

What are ACTH and CORT levels in cushing’s disease

A

ACTH and CORT are both high

76
Q

What is the classic presentation for cushing’s

A

Abnormal adipose deposits, thinning, bruising of skin, muscle atrophy of legs

77
Q

What is primary adrenocortical deficiency/addison’s disease

A

Decrease synthesis of all adrenocortical hormones as a result of autoimmune destruction of tissues

78
Q

Loss of cortisol can lead to

A

Hypoglycemia, muscle weakness, weight loss, and decreased HPA feedback

79
Q

Why is hyperpigmentation a result of decreased cortisol

A

Lack of negative feedback on HPA leads to increased ACTH secretion, which contains melanocytes stimulating hormone (alpha-MSH)

80
Q

Loss of aldosterone can lead to

A

Hyperkalemia, hypotension, metabolic acidosis, salt cravings

81
Q

Loss of androgens can lead to

A

Decreased libido in females

82
Q

How do you test adrenal cortex function

A

ACTH stimulation test- add exogenous ACTH and measure cortisol levels at t=0 and t=30 minutes

83
Q

What is the expected value after ACTH stimulation test in normal individual vs abnormal

A

Expect 2x cortisol in normal individual, subnormal responses are diagnostic of primary adrenal insufficiency, adrenals don’t respond to ACTH

84
Q

Where in HPA axis is impacted by primary adrenal insufficiency and what drugs would make the most sense to prescribe to improve condition

A

Adrenal cortex damaged- does not respond to ACTH

Tx: glucocorticoids (pred) and mineralcorticoids (fludrocortisone)

Physiology (10 decks)

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