Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Physiology II > E3- Random > Flashcards

E3- Random Flashcards

(65 cards)

Start Studying
1
Q

Thyroid deficiency during gestation leads to what?

A

cretinism

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

In a hyperthyroid state is colloid is reabsorbed more or less?

A

More

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

What type of cells release calcitonin?

A

Parafollicular

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

What 2 things inhibit the Na/I symporter?

A

Perchlorate and thiocyanate inhibit

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

What are the effects of a low iodide diet?

A

NIS is increased to compensate for deficiency
Lack of iodide in the diet –> cannot make iodine –> cannot T3 or T4 –> hypothyroidism
A lack of thyroid hormones –> lack of negative feedback on the HPA –> ↑ TRH and ↑ TSH –> ↑ TSH causes goiter

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

What are the effects of Graves’ disease

A

Autoantibodies that mimic TSH
Leads to hyperthyroidism
Excessive thyroid hormones –> increased negative feedback on HPA –> ↓ TRH and ↓ TSH –> stimulation of growth causes goiter

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

What does iodide bind to for transport to/across the apical membrane

A

Pendrin

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

What is Pendred Syndrome

A

Goiter and hearing loss develop during childhood

If iodide intake is scarce, pts develop goiter and hypothyroidism

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

Iodide efflux from the cell into the colloid occurs through the what channel?

A

Iodide channel anoctamin-1

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

On the colloid side of the apical membrane, iodide is oxidized to iodine by what?

A

thyroid peroxidase (TPO)

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

What inhibits thyroid peroxidase (TPO)?

A

Propylthiouracil

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

What is the Wolff-chikoff effect?

A

Iodine metabolism can also be regulated independently of TSH
Occurs when plasma iodide levels are elevated
Elevated iodide levels inhibit organification to prevent excess thyroid hormone production

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

Iodinated tyrosine molecules fuse together to form thyroid hormones, this fusion is catalyzed by what?

A

thyroid peroxidase (TPO)

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

Following stimulation by TSH, what induces the follicular cell to engulf the colloid containing Tg, T3 and T4?

A

Megalin

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

Lysosomes target the engulfed colloid and what splits the iodinated products from thyroglobulin?

A

Proteases

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

In the plasma T3 and T4 bind to what?

A

Thyoxine-binding globulin (TBG)

T3 and T4 have a very high binding affinity for proteins; very little free circulating hormone

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

In the follicular cell, MIT and DIT are diiodinated by what?

A

Deiodinases

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

What is associated with higher Tg levels in the plasma?

A

Hyperthyroidism

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

T4 is converted to active __ by ___ ring deiodination via deiodinases type __

A

T4 is converted to active T3 by outer ring deiodination via deiodinases type 1 and 2

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

T4 is converted to inactive __ by ___ ring deiodination via deiodinase type __

A

T4 is converted to inactive rT3 by inner ring deiodination via deiodinase type 3

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

T3 and T4 enter cells by transporters.

OATP transporter has preference for which hormone?

A

T4

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

T3 and T4 enter cells by transporters.

MCT transporter has preference for which hormone?

A

T3

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

Mutations in this which thyroid hormone transporter class are associated with psychomotor retardation and thyroid hormone resistance?

A

MCT

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

Which thyroid hormone has a greater blinding affinity for thyroid receptors?

A

T3

T3 is 10x more potent for all actions!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are some calorigenic actions of thyroid hormones?
Increased oxygen consumption resulting in: Increased basal metabolic rate (BMR) Increased body temperature Occurs in all tissues except the brain, gonads, and spleen
26
What are some metabolism actions of thyroid hormones?
``` Increases: -Glucose absorption from gut -Gluconeogenesis -Lipolysis -Protein synthesis and proteolysis (catabolic effect) ```
27
What are some CV actions of thyroid hormones?
T3 increases CO and ventilation T3 is chronotropic and inotropic T3 reduces vascular resistance
28
What are some SNS actions of thyroid hormones?
Increased synthesis of B-adrenergic receptors in cardiac/skeletal muscles and adipocytes (heterologous up-regulation)
29
What are some SNS actions of thyroid hormones?
Acts synergistically with GH and growth factors to promote bone formation Stimulates protein synthesis Maturation of CNS, axonal growth, and myelination (anabolic effect)
30
What layer produces mineralocorticoids (aldosterone)?
Zona glomerulosa
31
What layer produces glucocorticoids (cortisol)?
Zona fasciculata
32
What layer produces androgens (DHEA)?
Zona reticularis
33
What layer produces EPI and NE?
Adrenal medulla
34
The production of steroids is controlled by what?
ACTH
35
The production of catecholamines is controlled by what?
SNS
36
Precursor for all adrenocortical steroids is what?
Cholesterol
37
Free cholesterol is transferred to the mitochondria, and then to the inner mitochondrial membrane by what?
STaR
38
Cholesterol is converted to pregnenolone by what enzyme? (rate-limiting step and is dependent on STaR)
Desmolase
39
What stimulates desmolase?
ATCH
40
Cells in the zona glomerulosa are lacking what enzyme?
17a-hydrozylase; therefore, this zone does not produce glucocorticoids or androgens
41
What is a type of primary hyperaldosteronism?
Conn's syndrome
42
What are the effects of Conn's syndrome?
Increased Na reabsorption --> hypernatremia, fluid retention and HTN Increased K secretion --> hypokalemia Increased H secretion --> metabolic alkalosis Low renin levels
43
What are the effects of o 17a-hydroxylase deficiency?
Glucocorticoids and androgens are not produced Steroid intermediates in the aldosterone pathway build up resulting in overproduction of 11-deoxycorticosterone and corticosterone Corticosterone produces aldosterone-like effects (fluid retention, ↑ BP); the HTN inhibits renin secretion, causing aldosterone levels to be low Leads to the same outcomes as with Conn’s syndrome HTN Hypokalemia Metabolic alkalosis
44
Cells in the zona fasiculate are lacking what enzymes?
17,20-lyase; therefore, this zone does not produce androgens | Aldosterone synthase; therefore, the synthesis of aldosterone cannot be completed
45
Corticotrophin releasing hormone (CRH) stimulates corticotrophs to release ACTH. What are the effects of ACTH?
Stimulates adrenal gland growth Transfers cholesterol into the mitochondria Activates desmolase
46
What inhibits CRH?
Cortisol
47
Cortisol levels reflect a circadian and pulsatile release of ACTH. Greatest cortisol secretion occurs in the morning In periods of stress, ACTH secretion is enhanced as a result of what?
Increased amplitude of CRH burst, rather than frequency
48
What are the effects of cortisol?
Increase blood glucose by enhancing gluconeogenesis (essential for survival during fasting and stress) - Increases protein catabolism and lipolysis - Decreases glucose uptake by the tissues
49
What hormone enhances responsiveness to alpha 1 receptors, inhibits bone formation, increases proteolysis in muscle, and has anti-inflammatory and immunosuppressive effects?
Cortisol
50
Cells in the zona reticularis are lacking what enzyme?
Cells in this zone do not have 21B-hydroxylase; therefore, this zone does not produce aldosterone or cortisol
51
What are adrenal androgens called?
17-ketosteroids
52
What enzyme converts Progesterone to 11-Deoxycorticosterone?
21B-hydroxylase
53
What enzyme converts corticosterone to aldosterone?
Aldosterone synthase
54
What enzyme converts Pregnenolone to 17-hydroxypregnelone?
17a-hydroxylase
55
What enzyme converts Progesterone to 17-hydroxypregnelone?
17a-hydroxylase
56
What enzyme converts 17-hydroxypregnelone to DHEA?
17,20-lyase
57
What enzyme converts 17-hydroxypregnelone to androstenedione?
17,20-lyase
58
What enzyme converts 17-hydroxypregnelone to 11-Deoxycortisol?
21B-hydroxylase
59
What are the effects of a 21B-hydroxylase deficiency?
Cortex does not produce glucocorticoids or mineralocorticoids, resulting in Na loss and hypoglycemia Steroid intermediates build-up in the androgen pathway ACTH levels are high because of a lack of feedback control of cortisol on the pituitary Trophic effect of ATCH is seen Increased levels of DHEA and androstenedione result in masculinization of female
60
``` Penis-like clitoris Scrotum-like labia Ovaries are present Deepening of voice Increased muscle mass Amenorrhea and hirsutism Are seen with what? ```
21B-hydroxylase deficiency
61
Knowing that cortisol levels are higher than aldosterone and that cortisol binds with a higher affinity to produce mineralocorticoid activity, why does this not occur in normal conditions?
1. Cortisol circulates bound to albumin and CBG, allowing only a small fraction of free hormone to cross cell membranes 2. Aldosterone target cells have the enzyme 11B-hydroxysteroid dehydrogenase type II which converts cortisol into its inactive form (cortisone), which has less affinity to the MR 3. Aldosterone dissociates from the MR more slowly than cortisol
62
What type of MR and GR are predominant in the kidney and are specific for aldosterone?
Type I receptors
63
What type of MR and GR are expressed in all cells and are specific for glucocorticoids?
Type II receptors
64
11B-hydroxysteroid dehydrogenase type I (11B-HSD1) | promotes what conversion?
Cortisone to cortisol
65
11B-hydroxysteroid dehydrogenase type II (11B-HSD2) promotes what conversion?
Cortisol to cortisone

Physiology II (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions