Brainscape's Knowledge GenomeTM

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


See full index

COM Anatomy, Biochemistry, OS > Thyroid Gland Lopez Lecture > Flashcards

Thyroid Gland Lopez Lecture Flashcards

1
Q

Factors increasing T4 –> T3 conversion

A

obesity, cold, hyperthyroid

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

factors decreasing T4 –> T3 conversion

A 
pregnancy 
fasting
beta-blockers
hepatic/renal failure 
aging 
hypothyroid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Enzymes converting T4 –> T3 into its active form

A

deiodinases type 1 and type 2

outer ring iodination

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

Enzymes converting T4—> T3 into its inactive form

A

deiodinase type 3

inner ring iodination

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

TSH Abs do what?

A

stimulate TH synthesis

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

TH stimulatory factors

A

increased TBG levels such as during pregnancy

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

What proteins are synthesized under the influence of thyroid hormones?

A 
Na-K ATPase 
beta1 adrenergic receptor 
lysosomal enzymes 
proteolytic enzymes 
structural proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Na-k ATPase

A

in most tissues it is stimulated by thyroid hormone

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

proteins in cardiac muscle stimulated by TH

A

beta1 adrenergic receptors, Ca-ATPase

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

what factors inhibit TH synthesis?

A 
PTU 
thiocyanate 
percholate 
Wolff-Chakioff effect 
liver disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the first step of TH in acting on target tissues?

A

T4 has to be deiodinated by 5’ iodinase to T3

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

What actions does TH have on the body?

A

it acts on virtually all tissues of the body

creates heat, protein synthesis, increases basal metabolic rate, and oxygen consumption. acts synergistically with GH and somatomedins.

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

What agens prevent the conversion of T4 to T3?

A

hepatic failure, renal failure, beta adrengeric blocking agents, and pregnancy, fasting, stress

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

Obesity

A

increases T4—> T3 conversion

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

How does TH work inside the cell?

A

somehow it gets into the cell and binds to a nuclear receptor. it translocates to nucleus and stimulates nuclear transcription by binding to thyroid regulatory element on DNA

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

TH effects on growth

A

bone maturation and growth formation

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

TH on CNS

A

maturation of CNS

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

TH on BMR

A

increases synthesis of Na-K ATPases, O2 consumption, heat production, BMR

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

TH on metabolism

A

increase in glucose absorption, glycogenolysis, gluconeogenesis, lipolysis, protein synthesis and degradation (net catabolic)

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

TH and cardiovascular

A

increases cardiac output

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

What accounts for TH’s stimulation of metabolism?

A

the synthesis of Na-K ATPases: leads to O2 consumption and heat production

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

how does BMR increase under influence of TH?

A

new Na-K ATPases: a single does of T4 (thyroxine) can increase BMR a few hours after injection, and long lasting (6 hrs)

23
Q

What effect does hypothyroidism have on BMR?

A

decreases it

24
Q

what effect does hyperthyroidism have on BMR?

A

increases it

25
Q

TH effect on lipid metabolism

A

stimulates FA metabolism—> increases FA plasma levels, FA intake into the liver, beta oxidation of the FAs

26
Q

TH have what kind of proportional relationship to cholesterol and glycerol?

A

inverse

27
Q

what will blood cholesterol look like in patients with hypothyroidism?

A

it will be increased

28
Q

Vit. A and TH

A

TH is required for conversion of carotene to vitamin A

hypothyroidism can suffer blindness/yellowing of skin

29
Q

carbohydrate metabolism

A

TH increases gluconeogenesis, glycogenolysis to generate glucose

enhancement of insulin dependent entry of glucose into cells

30
Q

Cardiovascular effects

DIRECT (7)

A

increases proteins in muscles

1) myosin heavy chain alpha/beta ratio
2) Na-K ATPase
3) G protein stim/inhibitory ratio
4) Sarcoplasmic Ca-ATPase
5) increases ventricular contractility and function
6) decreases peripheral vascular resistance
7) beta adrenergic signaling

31
Q

Cardiovascular effects

Indirect (4)

A

increased heat production

decreased peripheral resistance

decreased diastolic pressure

increase in reflex adrenergic stimulation

32
Q

“ultimate” outcomes on the cardiovascular system due to TH

A

increase in cardiac rate and output

increase in blood volume (direct and indirect)

33
Q

Type 1 deiodinase

A

found mostly in the peripheral tissues

34
Q

Type 2 deiodinase

A

found mostly in the brain

35
Q

Pendrin

A

the transporter for iodide across the apical surface of the follicular cell

iodide, NOT iodine

36
Q

what are the “two” main players in the lumen of the follicle?

A

iodine (I2) and thyroglobulin with tyrosine moities

37
Q

intrathyroidal deiodinase = function?

A

breaks down the Thyroglobulin-MIT-DIT —> TG, tyrosine, MIT, DIT

38
Q

how much iodide will be taken up in the first 6 hours after injection?

what % indicates hyperthyroidism? hypothyroidism?

A

25%

60%

10% roughly

39
Q

transthyretin

A

responsible for getting T4 to brain, kind of like thyroid binding globulin

40
Q

what test can measure TBG?

A

T3 resin uptake test

41
Q

the T3 resin test will indicate what general character of T3 during hepatic failure?

A

increased T3-bound resin, because there is a DECREASE in liver produced TBG

42
Q

T3 resin levels will increase during

A

hepatic failure when TBG is decreased or when T3 levels are increased in the blood already

43
Q

T3 resin uptake will decrease when

A

TBG is increased or endogenous

T3 is decreased

44
Q

Thyroid hormones stimulate the

A

synthesis of cardiac beta-1 adrenergic receptors

used by norepinephrine

45
Q

what branch of the nervous system is highly functioning when TH is high in the body, and why

A

sympathetic nervous system because beta adrenergic receptors are being produced in quantity. so when TH is high, there are more beta-adrenergic receptors on the heart for example

46
Q

bone formation is stimulated synergistically with

A

TH and GH and somatomedins

47
Q

deficient TH during perinatal years

A

leads to abnormal development of synapses
decreased dendritic branching and myelination
neutral changes induced by thyroid hormone deficiency cause cretinism

48
Q

TH deficiency in children during the ____ period causes

A

perinatal = “of or relating to the time, usually a number of weeks, immediately before and after birth.”

decreased dendritic branching and myelination
abnormal development of synapses

49
Q

Metabolism: hypo/hyper

A

hyper: heat intolerance, weight loss, increased BMR
hypo: cold intolerance, weight gain, decreased BMR

50
Q

Skin: hypo/hyper

A

hyper: excess sweating
hypo: dry skin, myexidema

51
Q

Bone: hypo/hyper

A

hyper: osteoporosis
hypo: stunted growth

52
Q

CV system: hypo/hyper

A

hyper: tachycardia, atrial fibrillation, palpitations, high-output heart failure
hypo: bradycardia, decreased contractility, decreased cardiac output

53
Q

CNS: hypo/hyper

A

hyper: agitation, anxiety, difficulty concentrating, hyperreflexia
hypo: cretinism (congenital) in kids, listlessness/slowed movement/somnolence/impaired memory/decreased mental capacity

54
Q

INTESTINE: hypo/hyper

A

hyper: diarrhea
hypo: constipation

COM Anatomy, Biochemistry, OS (34 decks)

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