Endocrine Flashcards

1
Q

Hypothalamus and Pituitary secretions

A

Post pituitary - secretes directly to post pit which flows directly to blood (ADH and Oxy)

Ant Pit - Hypothalamus to Hypothalmic - hypophyseal portal veins to tropic cells which stim release of hormones to blood

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2
Q

Draw Overall hormone flow chart

A

On paper

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3
Q

What controls concentration of Free hormone

A

Rate of secretion is primary determinant

Degradation is at constant rate and is not regulated nor responsible for normal fluctuations

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4
Q

Dose threshold curve

A

SD50 is concentration of hormone that elicits half maximal response

Threshold is the minimum amount of hormone that produces a response

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5
Q

Sensitivity and effect on dosage curve

A

Decreased sensitivity shifts curve to the right, this effect can be overcome with concentration. Due to decreased receptors, affinity, increased degradation

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6
Q

Capacity and dosage curve

A

Decreased capacity will decrease maximal response and cannot be overcome with more H.

This is caused by a decrease in reacting cells or substrate available

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7
Q

Somatotrophs

A

Secretes GH

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8
Q

Thyrotrophs

A

Secrete TSH

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9
Q

Corticotrophs

A

Secrete ACTH

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10
Q

Lactotropes

A

Secretes PRL

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11
Q

Gonadotrophs

A

Secrete FSH and LH

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12
Q

Glycoprotein family

A

2 subunits: alpha is conserved and beta unique

FSH, LH, TSH

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13
Q

Somatomammotropin family

A

GH and PRL

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14
Q

POMC family

A

Single gene and CRH cleaves product to what is needed

ACTH

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15
Q

Hypo-Pit GH axis

A

GH stim by GHRH and in turn stims IGF 1

GH and IGF-1 stim Somatostatin to inhib GH secretion. They also neg feedback on GHRH and GH

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16
Q

Direct effects of GH

A

Increases IGF-1
Increases lipolysis by adipocytes
Inhibits glucose uptake

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17
Q

Indirect effects of GH

A

Through IGF 1, Induces skl growth through proliferation of chondrocytes and osteoblast proginator

Increases AA uptake and protein synth

Insulin like activity

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18
Q

Which zone of adrenal gland produces what hormones

A

ZG - mineralcorticoids (Aldosterone)
ZF - glucocorticoids (cortisol)
ZR - Androgens (DHEA and androstenedione)
Medulla - Epi

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19
Q

Blood flow of adrenal glands

A

Cortisol is secreted in artery in cortex which then flows to medulla to influence chromaffin cells and therefore epi secretion

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20
Q

Draw Steroidgenic adrenal pathway

A

On paper

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21
Q

Role of star

A

Steroidgenic acute regulatory protein transports chol to inner mito membrane to be altered by P450 scc

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22
Q

Actions of ACTH on adrenocorticol cells

A

Binds to receptor activating cAMP pathway

Increases hydrolysis of chol esters, increases star protein, increases growth and proliferation of ZF and ZR, increases steroidgenic enzymes (LDL-R and p450s)

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23
Q

Biological effects of Cortisol

A
  1. Carbohydrate, protein, and fat intermediary metabolism ie increases their blood levels by appropriate mechanisms
  2. Protective during acute stress: increases raw materials for correct response
  3. Anti-inflamm and immunosuppressive - via glucocorticoids and blocks all steps in inflamm pathway
  4. Permissive for other hormones by enhancing their effects
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24
Q

Chromaffin cells

A

Modified SNS ganglion

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25
Q

Adrenergic receptors

A

alpha 1 - increases IP3, Ca, and DG

Alpha 2 - decreases cAMP

Beta - Increase cAMP

26
Q

alpha receptors

A

Affinity for NE>E, respond to acute stress: vasocons of skin GI kidney, intestinal relax, constricts intestinal sphincters, dilates pupils, piloerection

27
Q

beta 1 receptors

A

NE=E affinity, increase heart rate, increase cardiac contraction, increase lipolysis

28
Q

Beta 2 receptor

A

E>NE, Intestinal relax, bladder wall relax, airway dilation, glycogenlysis

29
Q

Synergism

A

Hormones are often synergistic which increase their effectiveness over the sum

30
Q

ACTH stim test

A

Measure effect of adding ACTH, change of cortisol should be over 200. Impaired = adrenal insuff of impaired adrenal glands

31
Q

Thyroid follicle

A

responsible for secreting and synth thyroid hormone

32
Q

C cells

A

secrete calcitonin

33
Q

Colloid

A

glycoprotein = thyroglobulin

34
Q

TH synth

A

I pumped in by Na/I cotransporter

I pumped into colloid via pendrin (I/cl) after oxidized by peroxidase

I binds to TG and endocytosed to lysosomal digestion

35
Q

Regulation of TH

A

autoreg by lvls of I, low levels of I increases transport into follicular cell

hypo and pit - TRH and TSH

36
Q

Conversion of T4 to T3

A

Via 5prime deiodinase in most tissue (also to rT3 which is bio inactive)

Type 2 in pit for neg feedback on TSH

37
Q

T3 and cell effect mech

A

THR and Retinoid X = TRE

38
Q

TH effects

A

Increases Oxygen consumption and BMR

39
Q

TH and metabolism

A

Increases glucose absorb in gut, increases glucose production and oxidation. Increases lipolysis. Catabolic therefore thermogenic.

40
Q

TH and heart

A

Increases cardiac output and ventilation

41
Q

TH and growth

A

Promotes bone formation and bone maturation

42
Q

PTH general info

A

secreted by chief cells of parathyroid and is 84 AA long. Intraglandular degradation is control mech for intact PTH released.

43
Q

Hypercalcemia and PTH

A

decreases intact PTH and favors C-term fragments

44
Q

Hypocalcemia and PTH

A

Increases intact PTH and decreases C-term fragments

45
Q

PTH and Ca sensing control

A

Secretion is controlled by ca-sensing receptors. Decreased Ca increases PTH secretion.

If calcium is high, G proteins activated by sensor to: inhibit PKA (decreases secretion), increase PLC to IP3 which along with activation of intracell Ca pore leads to more cleavage and decreased secretion.

46
Q

Effect of PTH

A
  1. Increases Renal reabsorb of Ca
  2. Increases bone calcium mobilization
  3. Increases kidney activation of Vit D leading to increased Ca absorb in intestines
47
Q

Actions of Vit D on bone

A

Acts synergistically with PTH to promote bone mobilization and has indirect stim effects on bone mineralization

48
Q

Actions of Vit D on parathyroid gland

A

Feedback suppresion of PTH release

Modulates chief cell response to Ca and Vit D

49
Q

Actions of Vit D on Kidney

A

Stimulates synth of calbindin for intestinal Ca grab

Neg feedback on 25-hydroxycholecalciferol to 1,25 dihydroxy …

50
Q

Nuclear action of D3

A

Binds VDR in nucleus which dimerizes with RXR with CoA to attach to response element leading to transcription complex

51
Q

Cells of endocrine pancreas

A

beta cells = insulin
alpha cells = glucagon
Both go through pancreatic vein to liver to hepatic vein to elicit responses

52
Q

Actions of Insulin and glucagon

A

Insulin activated by high plasma glucose
Glucagon by low plasma glucose
Norm glucose is 70-110

53
Q

Mechanism of Ins Sec

A

Glucose binds to Glut 2 on beta cells. Glucose enters cell and is oxidized to ATP closing K channels leading to depol of beta cells. Depol opens Ca channels leading to Insulin secretion

54
Q

Incretin and insulin

A

GLP-1 Incretni activates Gs protein leading to camp to PKA to insulin secretion, similar to alpha 2 induction of insulin

Blocked by epi

55
Q

AA and endocrine pancreas

A

AA activates both insulin and glucagon pathways so blood glucose stays normal but insulin still promotes AA uptake

56
Q

Insulin and Skl M and Adipocytes

A

Insulin recruits Glut 4 uptake of glucose in these cells

57
Q

ADH origin

A

Originates in supraoptic nuclei of hypo

58
Q

Factors that increase ADH

A

Increased serum osmolarity, volume contraction, pain, nausea, hypoglycemia, nicotine

59
Q

ADH role

A

Increases water permeability of late distal tubule and collecting duct so more water reabsorption

Constricts vascular smooth muscle

60
Q

Control of ADH secretion

A

Hypothalmic osmoreceptors react to osmolarity greater than 280 mOsm

Atrial stretch receptors react to decreased stretch due to low blood volume

Carotid and aortic baroreceptors react to decreased blood pressure

All work to synth ADH and its effect on collecting duct epi