Shared Flashcard Set

Details

Intro to Endocrine: Adrenal Glands and Thyroid
Michael
60
Biochemistry
Professional
10/05/2011

Additional Biochemistry Flashcards

 


 

Cards

Term

 

 

 

 

Adrenal medulla

Definition

 

 

 

"independent" endocrine gland, NOT part of the HPTO axis

 

 

produces epinephrine, norepinephrine

 

Term

 

 

 

 

Adrenal gland blood supply

Definition

 

 

 

 

abdominal aorta-->vena cava

Term

 

 

 

glomerulosa

Definition

 

 

outermost layer of adrenal cortex

 

produces aldosterone

Term

 

 

 

 

 

fasciculata

Definition

 

 

 

middle layer of adrenal cortex

 

produces cortisol

Term

 

 

 

 

reticularis

Definition

 

 

 

innermost layer of adrenal cortex

 

produces androgens

Term

 

 

 

structural relationship between aldosterone and cortisol

Definition

 

 

 

so similar that can bind (relatively weakly) to each other's receptors

 

physiological impact

Term

 

 

 

 

parallel pathways of steroid hormone synthesis

Definition

 

 

 

there are multiple paths to the synthesis of each steroid hormone, dependent on MANY different enzymes

Term

 

 

 

 

 

ACTH

Definition

 

adrenocorticotropic hormone

 

released from ant pituitary stimulated by CRF(corticotropin-releasing factor) from hypothalamus

 

acts on adrenal cortex, stimulates release of cortisol and stimulates production of enzymes needed for steroidogenesis (in zona fasiculata)

Term

 

 

 

 

ACTH trophic effects

Definition

 

 

stimulates cell growth/proliferation in adrenal cortex

 

deficiency-->reduce in hormone production, atrophy of adrenal cortex (-->affects aldosterone)

 

 

Term

 

 

 

neg feedback of cortisol (3 places)

Definition

 

 

 

ACTH-->neg feedback on hypothalamus

 

cortisol-->hypothalamus and ant pit

 

Diurnal rhythm of cortisol driven by mechanism in hypothalamus

Term

 

 

 

 

Actions of cortisol

Definition

modulate inflammatory/immune response

 

stress response

 

counter-regulates insulin, maintains blood glucose level

 

mineralocorticoid effects in high conc (salt/water balances)

 

 

Term

 

 

 

stimulus for release of aldosterone

Definition

 

 

increase in plasma [K+] & increase in angiotensin II (low [Na+] and low blood volume)

Term

 

 

 

actions of aldosterone

Definition

 

alters number and activity of Na and K transport proteins in cell memb

 

kidney: aldosterone-->increase in Na+ resorption and loss of K+

 

at very high conc, can mimic cortisol actions (can bind to cortisol receptors)

Term

 

 

 

cortisol inhibitors

Definition

 

 

no direct inhibitors

Term

 

 

 

 

cortisol transport

Definition

 

 

 

cortisol-binding globulin (CBG) aka transcortin transports cortisol in bloodstream

Term

 

 

 

 

lack of cortisol

Definition

 

 

 

death

Term

 

 

 

 

cortisol and muscle

Definition

 

 

 

maintain muscle function, dec muscle mass

Term

 

 

 

cortisol and bone

Definition

 

 

decrease bone formation, inc resorption

Term

 

 

 

cortisol and connective tissue

Definition

 

 

 

decrease connective tissue

Term

 

 

 

cortisol and brain

Definition

 

 

 

modulate emotional tone, wakefulness

Term

 

 

 

 

cortisol and kidney

Definition

 

 

 

 

increase glomerular filtration and free water clearance

Term

 

 

 

 

cortisol and fetus

Definition

 

 

 

 

facilitates maturation of fetus

Term

 

 

 

 

 

cortisol and immune system

Definition

 

 

 

inhibits inflammation and immune response

Term

 

 

 

 

cortisol and CV system

Definition

 

 

 

maintain cardiac output, inc arteriolar tone, decrease endothelial permeability

Term

 

 

 

Cushing's syndrome

Definition

 

hypercortisol secretion:

central obesity, fatigue, hypertension, hirsutism (excessive hair), menstrual irregularity, depression, muscle wasting, edema, bone thinning, glucose intolerance, thinning of skin

Term

 

 

 

 

adrenal insufficiency

Definition

 

 

*aldosterone and adrenal androgens also dec

 

weakeness, hyperpigmentation of skin, weight loss, anorexia/nausea/vomiting, hypotension (orthostatic), salt craving, syncope (fainting)

Term

 

 

 

 

aldosterone inhibitor

Definition

 

 

 

 

Atrial netriuretic protein (ANP)

Term

 

 

 

 

aldosterone transport

Definition

 

 

 

bound to plasma proteins (minimal)--aldosterone-binding globulin (ABG), most transported in solution

Term

 

 

 

 

aldosterone removal

Definition

 

 

 

liver degrades, kidneys excrete

 

 

half-life=20 min

Term

 

 

 

 

aldosterone mechanism of action

Definition

 

 

 

 

enters nucleus, alters gene transcription

 

also has extra-nuclear (non-genomic) effects via activation of second messengers

Term

 

 

 

hyperaldosterone

Definition

 

 

centripetal obesity, fatigue, hypertension, hirsutism, amenorrhea, personality changes, peripheral myopathy, edema, Na retention, K/H loss, water retention, alkalosis

Term

 

 

 

hypoaldosterone secretion

Definition

 

 

weakness, hyperpigmentation of skin, weight loss, anorexia/nausea/vom, hypotension, salt craving, syncope, dec blood vol, hyperkalemia (hi K levels), acidosis

Term

 

 

 

chromaffin cells

Definition

 

 

 

 

adrenal medulla cells synth and secrete catecholamine hormone, innervated by sympathetic nervous system

Term

 

 

 

 

adrenal medulla hormones

Definition

 

 

 

catecholamine, epinephrine, norepinephrine

 

tyrosine precursor

 

final enzyme (PNMT) promoted by cortisol

Term

 

 

 

 

 

catecholamine actions

Definition

 

 

reg of blood glucose conc

 

act on sites innervated by sympathetic portion of autonomic nervous system

Term

 

 

 

 

catecholamine release stimulus

Definition

 

 

 

stimulation of sympathetic pre-gangionic neurons

Term

 

 

 

 

catecholamine inhibitors

Definition

 

 

 

 

no direct inhibitors

Term

 

 

 

 

catecholamine blood transport

Definition

 

 

 

 

free in solution, some bound to albumin

Term

 

 

 

 

catecholamine removal

Definition

 

 

Epi: metab'd by MOA

 

Norepi: metab'd by COMPT

 

excreted by kidney

 

1/2 life very short

Term

 

 

 

 

catecholamine mechanism of action

Definition

 

 

 

bind to adrenergic receptors in cell memb

Term

 

 

 

hypersecretion of epi/norepinephrine

Definition

 

 

pheochromocytoma--adrenal gland tumor

 

sustained hypertension, sweating, palpitations, hyperglycemia, glucosuria

Term

 

 

 

hyposecretion of epinephrine

Definition

 

secondary to lack of cortisol, and therefore reduced PNMT

 

orthostatic hypertension

Term

 

 

 

 

where thyroid hormone is produced

Definition

 

 

follicular cells, simple cuboidal epithelium in spherical form filled with colloid

Term

 

 

 

hormones released by thyroid gland follicular cells

Definition

 

 

 

 

thyroxine and triiodothyronine (T3/T4), tyrosine derivatives

Term

 

synthesis of T3/T4

Definition

requires uptake of iodine (I-) by NIS transporter (sodium-iodine symporter)

 

Na+ enters cell down conc grad, and I- enters against

 

dependent on Na-K ATPase to maintain Na+ gradient

 

NIS transporter-->30:1 conc gradient for iodide

 

Term

 

 

 

 

T3

Definition

 

 

biologically active form of TH

 

some T4 is converted to T3 in peripheral tissues (liver and kidneys)

Term

 

 

 

stimulus for release of TH

Definition

 

 

 

TSH Thyroid-Stimulating Hormone

Term

 

 

 

 

inhibitors of TH release

Definition

 

 

 

none

Term

 

 

 

 

TH transport in blood

Definition

not water soluble

 

plasma proteins:

70% thyroid-binding globulin (TBG)

30% transerythrin

.03% T4 in solution

.3% T3 in solution

Term

 

 

 

 

TH removal

Definition

 

 

by liver, kidneys, and skeletal muscle

 

half life T4: 6-7 days

half life T3: 18 hrs

Term

 

 

 

TH mechanism of action

Definition

 

 

enters cell by energy-dependent process, enters nucleus where it alters gene transcription-->enzyme levels

Term

 

 

 

 

TH action

Definition

 

 

affects growth

controls basal metabolic rate

interacts with (reinforces) activity of sympathetics

Term

 

 

 

 

TSH originates from:

Definition

 

 

 

HPTO axis

Term

 

 

 

 

TH inhibits/stimulates:

Definition

 

 inhibits: TSH and TRH release

 

stimulates: hypothalamic release of somatostatin (which inhibits TSH release)

 

long loop feedback ONLY (TSH does not inhibit hypothalamus)

Term

 

 

 

 

Aside from controlling TH synthesis, TSH also:

Definition

 

 

 

controls growth of thyroid cells and thyroid gland

Term

 

 

 

T4-->T3 conversion

Definition

 

 

de-iodination

Term

 

 

 

T4 in cell:

Definition

 

 

NOT biologically active, must be converted to T3 after uptake by the cell

Term

 

 

 

TH hypersecretion

Definition

CNS hyperexcitability

heat intolerance

increased sweating

weight loss

diarrhea

muscle weakness

fatigue

lack of sleep

tremor

Supporting users have an ad free experience!