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Pathophysiology > endocrine- basics > Flashcards

endocrine- basics Flashcards

1
Q

endocrine vs exocrine

A

exocrine - secretes out a duct to lining outside of the body or inside the body (lining of organ)

endocrine-no ducts, secrete into EXTRACELLULAR FLUID and act on TARGET cells ->hormones (chemical messengers- to remote parts of body)

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2
Q

what is the manner in which most endocrine cells secrete their hormones? why does this matter for checking hormone levels?

A

Usually pulsatile in manner- something messes up homeostasis and they are secreted to restore it
—> so ordering random hormone level is useless.

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3
Q

which endocrine gland is the only one that does NOT secrete in a pulsatile manner?

A

thyroid

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4
Q

what causes secretion of hormones? what causes inhibition of hormone secretion?

A

secretion: Disruption of homeostasis
inhibition: Restoration of homeostasis (reduction of stimulus) AKA “Negative feedback”

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5
Q

what are the two ways in which hormones can circulate? how is the majority of it circulating?

A

free (biologically active)

or protein bound (majority)

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6
Q

what does “trophic” mean?

A

the hormone stimulates a target cell and activates secretion of ANOTHER hormone from that gland
(AKA induces second messenger secretion)

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7
Q

what are the three types of hormones?

A

proteins (peptides)
steroids
amines

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8
Q

protein hormones: water or lipid soluble?

A

make up the majority of hormones

-are water soluble

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9
Q

steroid hormones: what are they derived from? water or lipid soluble?

A

derived from parent molecule: cholesterol

- all lipids

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10
Q

what is the significance of steroid hormones all being lipids?

A

CAN cross cell membrane, but don’t dissolve in plasma well- need carriers for plasma

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11
Q

amine hormones: what are they derived from? water or lipid soluble?

A

Derived from amino acid- tyrosine

tyrosine has ring that makes it resemble lipid, so these are relatively lipid soluble.

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12
Q

what two groups are included in the amine hormones?

A

thyroid hormone + catecholamines

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13
Q

which hormones act on intracellular receptors?

A

Steroid (& thyroid) : b/c pass through membrane easily

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14
Q

which hormones act on membrane receptors?

A

Protein & amine (except thyroid): b/c can’t pass through membrane
Require second messenger system- (change what goes on inside the cell = effect)

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15
Q

how does the 2nd messenger system work?

A
  1. Hormone (first messenger) does not enter cell - acts on membrane receptor
  2. Hormone-receptor binding triggers increase in an intracellular molecule/ion (second messenger)
  3. Second messenger orchestrates cellular effects, generally rapid
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16
Q

2nd messenger system: 1st + 2nd messenger- Linked by _____ in cell membrane

A

G-proteins

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17
Q

what are two 2nd messenger systems that we care about? and the other two?

A

cAMP (most common for h2o soluble hormones)
Phospholipase C
(also tyrosine kinase + cGMP)

18
Q

what is the most commonly used 2nd messenger?

A

cAMP

19
Q

what are the steps of the cAMP system? (7)

A
  1. Hormone binds receptor
  2. Receptor activates G protein
    * 3. Activated G protein activates adenylate cyclase
    * 4. Adenylate cyclase converts ATP to cAMP
    * 5. cAMP activates protein kinase A
  3. Protein kinase A phosphorylates cellular proteins
  4. Phosphorylated proteins alter metabolic activity of cell
20
Q

cAMP system: Increase in cAMP level is usually short or long? _______ converts cAMP to AMP?

A
  • short-lived

- Phosphodiesterase (PDE)

21
Q

what does the word “kinase” indicate?

A

phosphorylation (adding a phosphate group)

22
Q

what are the steps of the phospholipase C system? (8)

A
  1. Hormone binds receptor
  2. Receptor activates G protein
    * 3. Activated G protein activates phospholipase C
    * 4. Phospholipase C cleaves PIP2 into DAG & IP3
    * 5. IP3 causes Ca+2 release from endo(sarco)plasmic reticulum
    * 6. DAG & Ca+2 activate protein kinase C
  3. Protein kinase C phosphorylates cellular proteins
  4. Phosphorylated proteins alter metabolic activity of cell
23
Q

steroid and thyroid hormones diffuse into target cell, then bind to what 3 possible receptors?

A

steroid: Bind to nuclear + cytoplasmic
thyroid: bind nuclear + mitochondrial

24
Q

what are the actions of steroid + thyroid hormones once bound to cytoplasmic, nuclear or mitochondrial receptors?

A

cytoplasmic + nuclear: binds DNA, alters transcriptions- mRNA translated into new proteins

mitochondrial: alters mitochondrial activity = increased ATP

25
Q

what is different from the effects of steroid and thyroid hormones compared to other hormones (that use 2nd messengers) ?

A

steroid + thyroid: Effects take longer to occur BUT the effects last longer as a result

26
Q

how does the tyrosine kinase system work?

A

same as cAMP and phospholipase C system…

2nd messenger system- phosphorylation of intracellular proteins = effect on target cell.

27
Q

what are the two types of activity that hormones receptors may have with tyrosine kinase? (examples of each?)

A

Some hormone receptors have intrinsic tyrosine kinase activity (i.e. Insulin)
Some hormone receptors are associated with tyrosine kinase enzymes (i.e. Growth hormone)

28
Q

mutated tyrosine kinase often result in what?

A

cancer.

think of growth hormone that is assoc. with tyrosine kinase enzyme

29
Q

negative feedback may be ____ or ____, may involve ____ or _____ mechanisms

A

Can be direct or indirect

May involve neural or humoral mechanisms

30
Q

define “up-regulation”

A

Up-regulation: increase in receptor number, usually in response to decreased hormone levels
–> Increases sensitivity to hormone

31
Q

define “down-regulation”

A

Down-regulation: decrease in receptor number, usually in response to increased hormone levels
–>Decreases sensitivity to hormone

32
Q

what are the 3 mechanisms of endocrine control that the hypothalamus initiates?

A
  1. Produces & transports hormones to posterior pituitary gland for secretion
  2. Secretes regulatory hormones that control activity of anterior pituitary gland
  3. Contains cell bodies of sympathetic neurons that stimulate adrenal medulla
33
Q

what are the two anatomic relationships of the hypothal. to the pituitary ? both course through where?

A

neural and vascular

- both course through infundibulum

34
Q

what is the neural relationships of the hypothal. to the pituitary? which lobe?

A

Neuron cell bodies in supraoptic & paraventricular “nuclei” (groups of cell bodies)
-Posterior lobe

35
Q

what is the vascular relationship of the hypothal. to the pituitary? which lobe?

A

Hypothalamic-hypophysial portal system of capillaries

-Anterior lobe

36
Q

Neuron cell bodies in supraoptic nucleus primarily produce what hormone?
Neuron cell bodies in paraventricular nucleus primarily produce what hormone?

A
  • supraoptic (produces ADH/vasopressin)

- paraventricular (produces oxytocin)

37
Q

a collection of cell bodies in the CNS is called what? (weeds)

A

“nucleus”

38
Q

post. vs anterior pituitary: which is an actual gland?

A

post pituitary not an actual gland- just contains the nerve endings from the hypothal -neuronal relationship

ant pituitary - gland - hormonal relationship (hormones travel in portal system via veins)

39
Q

ADH/oxytocin transported via ___ for secretion into where?

A

via axons, secretion into hypophyseal veins in posterior pituitary.

40
Q

Hypothalamic neurosecretory neurons produce what two kinds or hormones? where are they released into?

A 
releasing hormones (RH) and release-inhibiting hormones (RIH)
BOTH into hypothalamic-hypophysial portal capillaries
41
Q

RH and RIH from hypothalamic neurosecretory neurons have what function?

A

Control secretory function of anterior pituitary endocrine cells

Pathophysiology (28 decks)

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