Anatomy Chapter 16: Endocrinology

Pineal Gland Releases..

melatonin

Thyroid/Parathyroid Releases..

thyroxine, parathyroid, calcitonin

Stomach Releases…

gastrin

Pancreas Releases…

insulin and glucagon

Kidneys Releases…

calcitriol, angiotensin II

Intestine Releases..

secretin

Testes Release..

testosterone, inhibin

Ovaries Release…

estrogen, inhibin

Adrenal Glands Release…

steroids (estrogen, proges, estro), catecholamine (norepi, epi)

Liver Releases…

erythropoietin, IGF

Heart Releases..

atrial natriuretic factor

Adipose Releases…

leptin (decrease appetite)

Hypothalamus Releases…

releasing and inhibitory hormones

Pituitary Gland Releases..

systemic hormones

Endocrine Cell

releases chemical messengers (hormones) into the bloodstream and BINDS to receptor on target cell

Properties of Hormones

released in LOW quantities, move through diffusion/plasma, bind to receptors on target cells, released in response to changes in homeostasis

Protein Hormones

hydrophilic, lipophobic (receptor ON membrane)

Steroid (lipid) Hormones

hydrophobic, lipophilic (receptor in cell)

Amino Acid Derived Hormone

depends, catecholamine: lipophobic

Hormone Regulation

negative feedback loop

Tropic Hormone

causes release of another hormone

Upregulation

increase receptor levels on target cells, increase response

Downregulation

decrease receptor levels on target cells, decrease response

Permisiveness

hormones regulating the receptor levels of other hormones

Neurotransmitters Amplitude-Modulated

"all or nothing", vary, on or off

Hormone Release Amplitude-Modulated

fluctuate between high and low, never approach 0, cyclic

Peptide/Protein Hormone Synthesis

preprohormone (INACTIVE) -> prohormone -> hormone

Amino Acid Derived Hormone Synthesis

from amino acids (tyrosine), stored in vesicles

Fat-soluble Hormone

lipophilic, hydrophobic, majority bound to transport protein, excreted in GI tract

Water-soluble Hormone

lipophobic, hydrophilic, free-flowing, excreted in urine

Half Life

time required to reduce blood concentration of a hormone by 50%

Increase Half Life

increased synthesis & secretion, bind to transport proteins, and CHEMICAL MODIFICATION of structure

Decrease Half Life

decrease synthesis & secretion, excrete , chemical degradation

Which Hormone has a Longer Response Time?

steroid hormone, b/c it makes hormone-receptor complex to increase DNA production etc.

Which Hormone has a Shorter Response Time?

protein hormone

Which Subunit of G-Protein Converts ATP to cAMP?

Ga s

Effects of cAMP

activates PKA, degraded by phosphodiesterase

One-Transmembrane spanning Receptors (1-TMS)

intracellular region contains kinase domain, directly activates enzymes w/o G-proteins

Nuclear Receptors

bind w/ lipophilic hormones, receptors inside the cell/nucleus, transcription

Hypophyseal Portal System

connects hypothalamus and anterior pituitary

Posterior Pituitary Hormones

vasopressin and oxytocin

Anterior Pituitary Hormones

prolactin, growth hormone, TSH, ACTH gonadotropins (LH & FSH)

Prolactin

stimulates mammary glands

Growth Hormone (GH)

stimulates musculoskeletal system

Thyroid Stimulating Hormone (TSH)

stimulates thyroid gland

Adrenocorticotropic Hormone (ACTH)

stimulates the adrenal cortex

Gonadotropins (LH & FSH)

stimulates gonads (ovary and testis)

Oxytocin

milk ejection, uterine contraction, feelings of contentment and calmness

Vasopressin (Antidiuretic Hormone)

water reabsorption in the kidney, Na+ reabsorption, vasoconstriction, aggression

Hypothalamic Anterior Pituitary Portal System

stimulus -> gland/cell -> efferent pathway -> response

What Stimulates GHRH?

hypoglycemia, stress, diurnal rhythm, exercise, sleep, estrogen, androgen

What Inhibits GHRH?

GHIH, GH, IGF1, sleep deprivation, hyperglycemia

Direct Effects of GH

lipolysis, bigger muscle tissue (anabolic), anti-insulin effect, protein synthesis, IGF secretion

What Stimulates TRH?

night-time, cold, nutrient status, diurnal rhythm

What Inhibits TRH?

t3/t4, GHIH

What are the Effects of T3/T4 in Most Cells?

increased metabolism and protein synthesis, tissue development

What are the Effects of T3/T4 on the Heart?

vasodilation, increased blood flow and heart rate, increased cardiac output

What Stimulates Prolactin?

stress, sleep, TRH, PrRP

What Inhibits Prolactin?

dopamine

What are the Effects of Prolactin?

increase lactation, growth development, metabolism, immunoregulation

What Stimulates CRH?

stress, hypoglycemia, anxiety, depression, serotonin

What Inhibits CRH?

cortisol, ACTH, hyperglycemia

Effects of ACTH?

aldosterone, cortisol, androgen precursors

Thyroxine Synthesis in Thyroid Gland

2 DIT = T4

Example of Protein bound to Thyroxine in the Blood

albumin

Effects of Thyroxine (T4)

increase ventilation, basal metabolic rate, heart rate, contraction, cardiac output, lipid and protein breakdown

Parathyroid Gland Anatomy

4 in thyroid, chief cells, oxyphil cells, secrete PTH

Parathyroid Hormone Effects

breakdown bone, increased calcitriol in kidney and calcium reabsorption in intestine

Zone Glomerulosa Hormones

mineralocorticoids (aldosterone)

Zone Fasciculata Hormones

glucocorticoids

Zona Reticularis Hormone

androgens

Alpha Cells of Pancreas Secrete..

glucagon

Beta Cells of Pancreas Secrete…

insulin and amylin (makes up 75%)

Delta Cells of Pancreas Secrete…

somatostatin

paraythroid

increases blood calcium levels

calcitonin

decreases blood calcium

what hormones are involved with amino acid derivative hormones?

L tyrosine, norepi, epi, dopamine, L dihydroxyphenylalanle

Gai

inhibits AC blocks production of cAMP

Gaq

activates PLC brekas down PIP2

cAMP, what does it activate

protein kinase A (PKA)

what does posterior pituitary secrete

vasopressin (water retention) and oxytocin (autism and milk)

hypothalamic anterior pituitary portal system

hypothalamus, anterior pituitary, endocrine