Endocrine i Flashcards

1
Q

Chem messenges

  • gap junctions
  • chems secreted to interstitial fluid
  • NTs
  • Hormones
A
  • cytoplasm to cytoplasm mvmnt of chem
  • autocrine and paracrine
  • released by synaptic cleft thru synaptic transmissino
  • released into blood to affect more distant targets
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2
Q

Endocrine vs. Nervous system

A

Endocrine is:

  • slower to respond
  • longer duration
  • signal intensity varies with concentration of hormone rather than frequency of APs
  • amplitude modulated rather than frequency modulated

Nervous system prety much just affects other neurons, muscle cells, and gland cells

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3
Q

amount of hormone released

A

nanomolar 10^-9 to picomolar 10^-12

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4
Q

Diabetes Mellitus

A

Type I

  • lack of insulin
  • autoimmune disease that destroys insulin producing cells in pancreas
  • treatment replaces insulin

Type II

  • Lack of sensitivity to insulin (and lack of insulin)
  • not enough receptors
  • treatment increases sensitivity, up regulates receptors, increases insulin, and decreases glucose
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5
Q

3 methods of homonal release

A
  1. Hormonal stimuli: one hormone stimulates the release of another
  2. Humoral stimuli: change in blood levels stimulates release
  3. Neural stimuli: neurons stimulate release
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6
Q

Tropic hormone

A
  • hormone that stimulates a release of another hormone at its target tissue
  • if target of tropic hormone fails, system will usually be flooded with tropic hormone
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7
Q

3 types of hormone

A

steroid (lipid soluble)
protein (water soluble)
biogenic amines (usually altered tyrosine) –> water soluble except thyroid hormones

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8
Q

Responsiveness of target cell depends on:

A
  • hormone concentration
  • abundance of target cell receptors
  • influence of other hormones (permissive, synergistic, and antagonistic)
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9
Q

eicosanoid

A

lipid soluble, but act like they’re water soluble

- deriitives of fatty acids, but use membrane surface receptors

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10
Q

Lipid soluble hormone binding to receptor

A
  1. travels thru blood with transport protein
  2. detaches and diffuses into target cell
  3. binds to receptor in cytoplasm or nucleus
  4. directly alters protein synthesis
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11
Q

Adenylate cyclase system

A
  • ligand binds to receptor
  • activates G protein
  • G protein activates adenylate cyclase (amplifier enzyme)
  • Converts ATP to cAMP (2 mess)
  • cAMP ativates protein kinase A
  • phosphorylation of proteins
  • alters cell function

cAMP is degraded by phosphodiesterase

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12
Q

Who uses the adenylate cyclase system?

A
glucagon
ADH
epinephrine
TSH
FSH
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13
Q

Phospholipase C Signal Transduction Mechanism

A

-ligand binds to receptor
-G protein activated
-G protein activates phospholipase c
conversion of PIP2 –> DAG and IP3
-DAG activates protein kinase C which phosphorylates proteins
-IP3 opens calcium channels on ER or cell membrane increasing free calcium in cytosol

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14
Q

hormones that use phospholipase c

A

Oxytocin
ADH
epinephrine

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15
Q

Membrane receptor-enzyme

A
  • extracellular receptor linked to intracellular enzyme
  • ligand binds and activates protein kinase enzyme
  • e.g. tyrosine kindase uses ATP to phosphorylate proteins
  • e.g. guanlate cyclase turns GTP into cGMP which alters other proteins

phosphodiesterase turns cGMP into GMP

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16
Q

Effects of modifying proteins

-what usually modifies them?

A
  • metabolic changes
  • transportation changes
  • dif gene expression
  • changes protein func.
  • causes muscle contraction

-calcium or phosphate

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17
Q

What are the purely endocrine glands?

A
  • pituitary
  • thyroid
  • parathyroid
  • adrenal
  • pineal
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18
Q

what separates the adenohypophysis from the neurohypophysis

A

pars intermedia

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19
Q

Hormones of anterior piuitary

Which are tropic?

A
-human growth hormone
thyroid stimulating hormone
prolactin
follicle simulating hormone
luteinizing hormone
adrenocorticotropic hormone

all except prolactin and growth hormone

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20
Q

Growth hormone effects

A
  • lipolysis = release of fatty acids for energy
  • AA uptake/ protein synthesis
  • gluconeogenesis and glycogenolysis in liver

-stimulates liver to release IGFs to stimulate growth of cartilage, bone, and (proteins in skeletal muscles)

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21
Q

Factors affecting GH release

A
  • Age –> less
  • Time –> more in morning
  • blood levels –> increases with AA and decreases if glucose/fatty acids in blood
  • emotion –> stress
22
Q

Posterior Pituitary

A

doesn’t synthesize hormones

  • stores and releases oxytocin and ADH
  • via hypothalamohypophyseal tract
23
Q

oxytocin

A
  • made in paraventricular nucleau
  • during and after delivery of baby
  • stimulates smooth muscle contraction of uterus and mammary glands
  • Mile EJECTION
24
Q

ADH

A
  • made in supraoptic nucleus
  • decreases urine production
  • causes kidneys to return more water to blood
  • constriction of arterioles to increase BP
  • stops water loss thru sweat

-stimulated by high blood osmotic pressure

25
Thyroid gland - anatomy - cells - hormones
- 2 lobes with isthmus inferior to larynx - Follicular cells make thyroid hormones (T3 and T4) - parafollicular (C) cells make calcitonin
26
Thyroid hormone function
- increases metabolism - uses glucose and oxygen to make energy and heat - lipolysis - gluconeogenesis and glycogenolysis - increases oxygen delivery - works with growth hormone to promote tissue growth and development - BP maintenance stimulated by situiations that require ATP T4 is inactive
27
Production of thyroid hormone
- iodine from blood is trapped in colloid space as I2 - thyroglobulin is created (nucleus - RER- golgi- secratory vessicles- colloid) - iodine is oxidized - tyrosines on thyroglubulin are iodinied - coupling of T2 and T1 - pinocytosis and digestion of colloid - secretion of thyroid hormone through exocytosis to blood
28
calcitonin
- involved in calcium metabolism, but not significant in humans - inhibits osteoclast activity
29
Parathyroid glands
- 4 in thyroid | - make parathyroid hormone
30
Parathyroid hormone
- increases osteoclast activity - makes kidney return calcium to blood - stimulates kidneys to release calcitriol which is the active form of vit D, which allows calcium to be absorbed by food
31
Adrenal glands | -anatomy / labels
Cortex - zona glomerulosa = mineralocorticoids - zona fasciculata = glucocorticoids - zona reticulata = gonadocorticoids Medulla -chromaffin cells which make catecholamines
32
Aldosterone
- Regulates ion concentration in kidneys - reabsorbs Na and water - excretes potassium and hydrogen - works with adh - affects water balance and ph triggered by low blood pressure and high K+ (a little bit by ACTH)
33
How is aldosterone secreted?
Renin-Angiotensin-Aldosterone Mechanism - low BP stimulates kidneys to release renin - triggers formation of angiotensin I from angiotensinogen from liver - ACE in lungs convert A I to A II - stimulates aldosterone release and vasoconstriction of arterioles Atrial natriuretic peptide (ANP) blocks renin and aldosterone to decrease BP
34
Cortisol
- last hormone of HPA axis - response to stress - reduces inflammation - aids thyroid hormones in gluose metabolism
35
Androgens
- stimulated by ACTH - mostly DHEA - causes male secondary sex characteristics and pubic/axillary hair in females - causes sex drive in females --> insignificant in males bc of testosterone - levels rise from ages 7-13
36
Pancreas
1% endocrine, 99% exocrine - pancreatic islets (of langerhans) - alpha cells = glucagon - beta cells = insulin
37
insulin secretion
- Beta cells have GLUT2 which is insulin independant - glucose enters beta cell thru Glut2 transporters - glucose is phosphorylated and turned into pyruvate - pyruvate enters mitochondria and metabolized via citric acid cycle - ATP from this blocks K channels, depolarizing the cell - depolarization opens Ca channels - Ca stimulates the release of insulin by exocytosis
38
insulin effect
- binds to receptor - causes GLUT4 on secratory intracellular vessicle to join membrane - glucose enters through GLUT4 lowers blood sugar by increasing uptake of glucose
39
Diabetes Mellitus - types - symptoms
``` (I) = lack of insulin (cured by giving insulin) (II) = low sensitivity to insulin (cured by increasing sensitivity and insulin --> aerobics help) ``` polyurea -- bc osmotic diuresis polydipsia -- bc peeing all the time polyphagia -- bc cell hunger
40
Glucagon
- targets liver and skeletal muscle - gluconeogenesis = glucose from lactic acid and AAs - glycogenolysis = break down glycogen
41
Insulin
- glycogenesis = builds glycogen - increases AA uptake and protein synthesis - lipogenesis = synthesis of fatty acids
42
Ovaries
- makes gametes and hormones - make 2 estrogens (estradiol and estrone) and progesterone - regulate menstral cycle, pregnancy, lactation, and female sex characteristics - inhibin inhibits FSH - relaxin loosens pelvic girdle during pregnancy and some of cycle
43
Testes
- makes gametes and hormones - makes testosterone --> regulates sperm production and meintains sex characteristics - inhibn inhibits FSH
44
Pineal gland
- on roof of 3rd ventrical at midline in epithalamus - masses of neuroglia and pinealocytes - melatonin = amine hormone derived from serotonin - biological clock - more melatonin when its dark acts on reticular formation in brain
45
Thymus - where? - hormones? - function?
- behind sternum; between lungs - thymosin, thymopoietin, thymic factor, thymic humoral factor - involved in T lymphocyte maturation
46
Progesterone
- preps for pregnancy | - aids in fetal development
47
Adipose tissue
- leptin targets brain | - promotes satiety
48
heart
- Atrial Natriuretic Peptide - targets smooth muscle cells in blood vessel walls and kidney tubules - vasodilation - natriuresis and fluid loss in kidneys - decreases BP
49
Kidneys
Erythropoietin -increases rate at which erythrocytes are made in red bone marrow Renin -part of RAA system Calcitriol -stimulates small intestine to absorb calcium
50
Stages of stress response (and name of it)
GAS = general adaptation syndrome 1. initial fight or flight 2. slower resistance reaction 3. exhaustion
51
results of prolonged stress
- muscle deterioration - immune system suppression - ulcers - failure of beta cells in pancreas
52
short term vs long term stress respons
Short: - increased heart rate, blood flow, metabolism - glygogenolysis - dilation of bronchiles - change in bloodflow patterns - EPI and NE Long: - increased BP - retention of salt - gluconeogenesis - suppression of immune system - cortisol, hGH, T3 and T4