Lecture #1 -- Intro Flashcards Preview

Physio -- Endocrine > Lecture #1 -- Intro > Flashcards

Flashcards in Lecture #1 -- Intro Deck (71):
1

Tyrosine is converted into what two types of hormones

Thyroid Hormones
Catecholamines (Epinephrine)

2

Describe the physical structure of thyroid hormones.

Double Tyrosine
Critical Incorporation of 3-4 iodine atoms

3

Describe how thyroid hormones are generated

Modification of a Tyrosine residue in thyroglobulin
Post translationally modified to bind iodine
Proteolytically cleaved into T3 and T4
T3/4 bind to thyroxin binding globulin for transport

4

Catecholamines are both ______ and ________

neurohormones and neurotransmitters

5

Two amino acids used to generate amine hormones?

Tryptophan
Glutamic Acid

6

Tryptophan is the precursor of _________

Serotonin and Pineal Hormone Melatonin

7

Glutamic Acid is converted to _________

Histamine

8

All steroid hormones are derived from ______

Cholesterol

9

List the five types of steroid hormones and an example

Glucocorticoids - Cortisol
Mineralocortioids - Aldosterone
Androgens - Testosterone
Estrogens - Estradiol, Estrone
Progestogens - Progesterone

10

Where in the cell are enzymes that produce steroid hormones

Mitochondria and Smooth ER

11

Steroids are not water soluble. So what?

They have to be carried in the blood complexed to binding globulins

12

Steroids secreted in one cell may be converted to _______

active steroid in the target cell

13

Common prefix for the enzymes that convert steroids

CYP

14

Other name for 21-hydroxylase

CYP21A2

15

Review the picture of steroid hormone conversion -- page 8

Should have been paying attention on that one...

16

CYP important from conversation from testosterone to estrogen

CYP19

17

CYP that makes cortisol

CYP11b1

18

CYP importnat for aldosterone production

CYP 11b2

19

What is the rate limiting step in the process of steroid hormone synthesis?

Transport of free cholesterol from cyto into mito
Performed by Steroidogenic Acute Regulatory Protein

20

Where does the steroidogenesis precursor cholesterol come from?

Cholesterol synthesized in the cell from acetate
Cholesterol ester stores in intracellular lipid droplets
Uptake from cholesterol-contining LDL

21

Which source of cholesterol is most important in chronic stimulation?

Lipoproteins

22

What "vitamin" is also made from cholesterol

1, 25 - dihydroxy Vitamin D3

23

Most abundant precursor of Eicosanoid hormones

Arachadonic Acid
(Polyunsaturated Fatty Acids)

24

How long do eicosanoids last?

They are typically active for only a few seconds before they are metabolized

25

Principal groups of eicosanoid hormones? (4)

Prostaglandins, Prostacyclin, Leukotrienes, and Thromboxanes

26

What are eicosanoids?

A large group of molecules derived from polyunsaturated fatty acids

27

The physiological effers of hormones deped largely on their concentrations where?

Blood and Extracellular Fluid

28

Three factors that determine the concentration of hormone seen by a target cell?

Rate of Production
Rate of Delivery
Rate of Degradation and Elimination

29

Most highly regulated aspect of endocrine control?

Rate of Production

30

What factor plays a major role in the efficacy of controlling circulating hormones by shutting off secretion?

Hormone half life

31

_____ input to hypothalamus stimulates synthesis and secretion of releasing factors

Neural

32

What does chronotropic control refer to?
Examples?

Endogenous neuronal rhythmicity
Diurnal rhythms, Circ rhythms, sleep-wake cycle

33

How frequent is a circhoral rhythm?

Frequency of approx 1 hr.

34

How frequent is a ultradian rhythm?

Longer than an hour, less than 24

35

How frequent is a circadian rhythm?

Periodicity of approx 24 hours.

36

Circadian clock is located in the ______ nucleus

Suprachiasmatic

37

Give an example of the significance of pulsatile hormone release.

GnRH one hourly --- > Normal gonad function
Slower Frequency --> Diminished Gonadal Fxn
Faster Frequency/Continuous --> Inhibits gonadal steroid production

38

Give an example of substrate-hormone control

Glucose and Insulin
(High Plasme Glu triggers insulin, insulin lowers glucose levels, decreased insulin response)

39

What is MCR (in regard to endocrine)

Metabolic Clearance Rate
Defines the Quantitative Removal or Hormone from Plasma

40

Who clears most of the hormones from blood
Who does a little

Liver and Kidneys
Target tissue responsible for small fraction

41

99% of excreted hormone is _____ or _______

Degraded or Conjugated by Phase I and II enzyme systems

42

Compare the MCR of T3 and T4

T3 -- 0.75 Days
T4 -- 6.7 Days

43

Two types of hormone solubility?

Water and Lipid Soluble

44

List water soluble hormones

Catecholamines
Peptide/Protein Hormones

45

List lipid soluble hormones

Thyroid Hor
Steroid Hor
Vit D3

46

Three most common second messenger systems for cell surface receptors

Adenylate Cyclase (ATP-->cAMP)
Guanylate Cyclase (GMP-->cGMP)
Calcium and Calmodulin (Phospholipase C-->PIP+DAG)

47

Four types of receptors to remember

Receptor Kinases
Receptor-Linked Kinases
G Protein
Ligand Gated Ion Channels

48

Important trait of second messenger activity

Usually allows for amplification of individual signals

49

Give a few examples of receptors that use Adenylate cyclase

beta-adrenergic
LH, FSH, TSH, hCG
Glucagon
Vasopressin
ACTH

50

Receptors for growth factors, insulin, etc. usually have _____ activity

intrinsic tyrosine kinase

51

Receptors for Growth Hormone, Prolactin, and other cytokines typically have _______ activity

Soluble, Intracellular kinase
(JAK-STAT)

52

Give examples of receptors with intrinsic serine/threonine kinase activity

inhibin, activin
TGF-beta
Mullerian Inhibitory Factor

53

Describe the process of lipid-soluble hormone binding

Hormones diffuse through lipid bilayer
Binds receptor in cyto or nuc, conformational change
Complex binds specific DNA response element in regulatory region

54

Why do lipid hormones take longer to trigger a response

Requires transcription/translation to evoke physiological responses

55

What is homologous desensitization?

Hormonally induced negative regulation of receptors

56

Why is homologous desensitization important?

Protects from toxic effects of too much hormone

57

What is heterologous desensitization?

When exposure of the cell to one agonist reduces the responsiveness of the cell to any other agonist that acts through a different receptor

58

When does heterologous desensitization tend to occur?
(Whats happening, how long)

Through receptors that act on Ad. Cyclase system
Slower onset than homologous desensitization

59

What hormone can be deficient without causing disease?

Calcitonin Deficiency

60

Common causes of endocrine deficiency?

Dysfunctional Gland
Genetic Defects
Receptor Inactivating Mutation

61

Examples of gland problems leading to endocrine deficiency

Infection, Infarction, Tumor, Autoimmune

62

Examples of genetic defects that might cause endocrine deficiency?

Gene Mutation, Protein Folding Defects, Enzymatic Defects

63

How does hormone excess tend to happen?

Overproduction by normal glad to secrete it
Production by non-endocrine tissue
Exogenous ingestion
Receptor activating mutations
Cancer of non-endocrine, allowing dediferentiation
Anti-receptor antibodies

64

Example of a Dynfunctional glad deficiency

Type I Diab

65

Give an example of a genetic defect deficiciency

Congenital Adrenal Hyperplasia

66

Give an example of a receptor inactivation that causes hor deficiency

Testicular Feminization Syndrome

67

Example of overproduction by a gland that normally secretes is

Cushing Syndrome

68

Examples of endogenous ingestion of hormones

Anabolic Steroid Abuse

69

Example of a receptor activating mutation?

McCune-Albright syndrome

70

Example of malignant transformation in endocrine disease?

Grave's Disease

71

Aberrant increase in the level of a specific hormone will tend to cause _________
Example.

A Decrease in Available Receptors
Type II Diab