Lecture 66 Flashcards by Shelby Rainbolt

Growth hormone is also called

somatotropin

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Growth hormone is the number 1 most important thing for

GROWTH (bones, muscle, etc)

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Growth hormone (somatotropin) is a single chain _______

polypeptide (AA sequence varies by species)

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GH secretion is described as

Pulsatile (burst of release every 2-4 hrs)

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GH secretion: _______ pattern in fish and mammals

circadian (depends on species nocturnal pulses)

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Sexual dimorphism in GH secretion for _______ (3 groups of animals)

Humans, rodents, fish

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Growth hormone (somatotropin): Large, nocturnal pulses in _______, more sustained secretion in _______

males; females

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Growth hormone (somatotropin): (Decreases/ increases) with age

decreases

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_______ explains the “growth spurt” at puberty

Growth hormone (somatotropin) increases in frequency and magnitude of pulses

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Regulation of GH secretion: Stimulators of GH

GHRH, Decreased glucose, Decreased FFA, Increased AA (ex: arginine), Puberty (estrogen/testosterone)

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Does Hypoglycemia/fasting/starvation stimulate or inhibit GH

STIMULATE

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Regulation of GH secretion: Inhibitors of GH

Somatostatin, Increased glucose, FFA, GH, Obesity, Somatomedins (IGFs)

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_______ 3 stimulators of GH are in the “nutrient regulation” category

Decreased glucose, Decreased FFA, Increased AA (ex: arginine)

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why is nutrient regulation important

we need building blocks for growth (decrease in nutrients is stimulatory because that means they’ve been used up)

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How can GH be its own inhibitor

negative feedback (prevent us from making too much)

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Somatomedins (IGFs): _______ is it? _______ does IGF stand for?

hormones produced by the liver that stimulate somatostatin from Hypothalamus; IGF= insulin-like growth factor

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where do Somatomedins (IGFs) inhibit

at anterior pituitary

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GH has metabolic actions on (4)

liver, muscle, adipose, bone

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_______ synthesis carbohydrate and lipid _______

linear and organ; protein; metabolism

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Actions of GH: Direct anabolic actions of GH (GH acting on self)

Increased Ca absorption from gut, P reabsorption from kidney, protein synthesis in liver

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Define anabolic and catabolic

anabolic is build up; catabolic is break down

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Actions of GH: Indirect anabolic actions via somatomedins (insulin-like growth factors - IGF) _______ are the IGF’s involved

IGF-1 (somatomedin C); IGF-2(somatomedin A); stimulated by GH**

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Actions of GH: Indirect anabolic actions via somatomedins (insulin-like growth factors - IGF) _______ do these lead do (3)

Increased lean muscle mass, linear bone growth, organ size/function

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Where are IGF 1 and 2 made _______ receptors do they act on

made in liver; act on receptors similar to insulin receptors (TYROSINE KINASE activity)

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Explain the general process of indirect anabolic actions via somatomedins (insulin-like growth factors - IGF)

GH stimulates IGF or Somatostatin then IGF or somatostatin then acts on tissue

Direct catabolic effects of GH: Increased _______ in liver

gluconeogenesis (break down to make glucose)

Direct catabolic effects of GH: Increased gluconeogenesis in liver helps maintain _______ within normal range

blood glucose

Direct catabolic effects of GH: Increased gluconeogenesis in liver Maintains blood glucose within normal range _______ decreases because of this? _______ results because of the decrease

Decreases glucose uptake in skeletal muscle has temporary insulin resistance (means the glucose is available for other organs)

Direct catabolic effects of GH: Increase _______ in adipose tissue

lipolysis

Direct catabolic effects of GH increases lipolysis in adipose tissue _______ 2 things does this lead to When there is a release of FFA into blood. _______ does FFA bind to?

Release of FFA into blood, Increased formation of ketones

_______ does it turn into?

Albumin; NEFA's

An increase in ketone bodies can lead to

metabolic acidosis

Abnormal secretion of GH: A deficiency/lack of GH secretion leads to

dwarfism

_______ are the 2 types of dwarfism we discussed

pituitary dwarfism & disproportional dwarfism

_______ is pituitary dwarfism

autosomal recessive common in GSD

_______ is disproportional dwarfism

shortened long bones common in dachshunds, corgis, basset hounds

which of the following will STIMULATE GH secretion

Decreased FA's

Excessive GH secretion leads to

acromegaly

Where/ how do we see acromegaly (excessive GH secretion) in cats

Pituitary tumor in cats

Excessive GH secretion (acromegaly) in dogs causes

Increased progesterone during diestrus in dog

Increased progesterone during diestrus in dog _______ type of dogs experience this

ALL intact females go through a period after estrus when progesterone increases, regardless of being pregnant or not

Increased progesterone during diestrus in dog and _______ does this lead to

High progesterone which antagonizes insulin, stimulates GH; LEADS to : Insulin resistance

_______ will inhibit ADH

Hypervolemia

_______ are the 2 hormones released from posterior pituitary

Antidiuretic hormone (ADH;vasopressin/arginine vasopressin) and Oxytocin

ADH and Oxytocin are classified as _______ kind of hormone

neuropeptide (hormone made in neurons)

_______ hormone is synthesized primarily by neurons in supraoptic nuclei of hypothalamus

Antidiuretic hormone (ADH;vasopressin/arginine vasopressin)

_______ is the peptide precursor for ADH

prepropressophysin

_______ makes up prepropressophysin

ADH, neurophysin 2, signal peptide

_______ hormone is synthesized primarily by neurons in paraventricular nuclei of hypothalamus

Oxytocin

_______ is the Peptide precursor for oxytocin

prepro-oxyphysin

_______ makes up prepro-oxyphysin

oxytocin, neurophysin 1, signal peptide

Hormones released from posterior pituitary: Secretion of _______ in posterior pituitary

vesicles

Hormones released from posterior pituitary: Action potential from cell body in _______

hypothalamus

Hormones released from posterior pituitary: _______ does the AP from the hypothalamus cause to happen

Causes Calcium to enter nerve terminal, and exocytose vesicles where they'll be picked up by the capillary plexus

Hormones released from posterior pituitary : After each hormone is synthesized _______ steps does it go through (3)

Golgi removes signal peptide and packages pro-hormone into vesicles, Neurophysin will be removed as it travels down the axon to the posterior pituitary, Ready to be released once in posterior pituitary

Stimulation of oxytocin secretion: _______ is the main stimulus for oxytocin? Where are the receptors?

Major stimulus is suckling; Sensory receptors on myoepithelial cells of alveoli in mammary gland

_______ does suckling result in?

Results in milk let-down

Other than suckling, _______ is the other stimulus for oxytocin

Stimulation of cervix by fetus

Stimulation of oxytocin secretion: Stimulation of cervix by fetus results in

Results in uterine contractions (Oxytocin acts on smooth muscle of uterus)

T/F Uterine contractions is an example of negative feedback

F; positive feedback

Oxytocin effect on males

acts on testes, epididymis and prostate to aid in sperm movement and ejaculation

Regulation of ADH secretion: Stimulators (7)

Increased plasma osmolarity, Decreased blood volume(hypovolemia), Decreased blood pressure, Pain, Nausea, Hypoglycemia, Nicotine, opiates

Stimulation of ADH results in _______ of water

REABSORPTION

Regulation of ADH secretion: Inhibitors (5)

Decreased plasma osmolarity, Increased blood volume(hypervolemia), Increased blood pressure, Ethanol, Glucocorticoids

Regulation of ADH secretion: _______ happens when plasma osmolarity is increased

increase water reabsorption; increase urine concentration

Regulation of ADH secretion : _______ happens when blood volume decreases (ex: hemorrhage)

stimulates baroreceptors

decreases blood pressure

Loss of _______ percent of ECF will result in a decrease in blood volume (hypovolemia)

Regulation of ADH secretion: How does pain stimulate ADH

We actually don't know, we know that pain stimulates the hypothalamus

Regulation of ADH secretion: How does nausea stimulate ADH

there is a loss of fluids

Regulation of ADH secretion: How does hypoglycemia stimulate ADH

weak stimulus- probably acting with osmotic triggers

Regulation of ADH secretion: How does Glucocorticoids inhibit ADH

they decrease renal sensitivity to ADH

_______ 2 areas of the nephron are water permeable

Distal convoluted tubule and collecting duct are permeable to water (water can be reabsorbed into blood)

In the nephron, under the influence of _______ water can be reabsorbed into blood

UNDER THE INFLUENCE OF ADH

_______ are the 2 main actions of ADH

kidney and vascular smooth muscle

_______ ADH-V receptor does the kidneys use? Vascular smooth muscle?

Kidney and V2 receptor (adenylyl cylase and cAMP) VSM and V1 receptor; increases BP

Vascular smooth muscle contraction causes constriction of

arterioles

How does ADH affect the kidney and free water absorption

Increase water permeability of principal cells in distal convoluted tubules and collecting ducts of kidney

_______ are the 3 main abnormal ADH secretion diseases we discussed in class

Central diabetes insipidus; Peripheral or nephrogenic diabetes indipidus; Syndrome of inappropriate ADH secretion

_______ disease is caused by a lack of ADH secretion likely due to a head injury

Central diabetes insipidus

_______ disease is caused by the posterior pituitary being normal, but principal cells in collecting duct are unresponsive to ADH

Peripheral or nephrogenic diabetes insipidus

_______ disease is caused by a defect in V2 receptor or G protein/ andenylyl cyclase

Peripheral or nephrogenic diabetes insipidus

_______ syndrome is related to excess ADH released from posterior pituitary or not at all (Ex: disorders in brain, certain medications)

Syndrome of inappropriate ADH secretion (there is no feedback inhibition)

Central diabetes insipidus: _______ happens to ADH, Urine, ECF osmolarity

ADH decrease; Urine increase; ECF osmolarity increase (something is inhibiting ADH release)

Peripheral or nephrogenic diabetes insipidus: _______ happens to ADH, Urine, ECF osmolarity

ADH increase; Urine dilute; ECF osmolarity increased

Syndrome of inappropriate ADH secretion: _______ 3 things result from this

Hypervolemia and hyponatremia; Urine very concentrated