Anatomy and Physiology 2 Chapter 18 - Rest of Major Hormones

what is the thyroid gland composed of and what are the 3 parts?

follicles

1. follicle cells = produce TH

2. follicular cavity = has follicle cells around it

3. parafollicular (C) cells = produce calcitonin

what are 2 hormones of the thryoid gland

1. thyroid hormone (TH) - T3 and T4

2. calcitonin

thyroid hormone (TH) - T3 and T4

stimuli:

1. TSH

2. cold

targets: many cells

effects:

1. strong, immediate, and short-lived increase of cellular metabolism = growing for normal development of skeletal, muscular, and nervous system

2. stored in cell cytoplasm

3. increase ATP production = when binded to mitochondria

4. increase transcription of enzyme for E use, glycolysis, Na/K ATPase pumps

inhibitors:

1. high T3 and T4 decrease TRH

2. extreme anxiety

calcitonin

stimuli: high blood Ca2+

targets: various

effects:

1. stimulates excretion by kidneys

2. prevents absorption by GI tract

3. stimulates bone growth and skeletal mineral deposition

4. inhibits Ca2+ removal from bone

inhibitors: normal blood Ca2+

what is the hormone of the parathyroid gland?

parathyroid hormone (PTH)

parathyroid hormone (PTH)

stimuli: low blood Ca2+

targets: various

effects:

1. mobilizes Ca2+ from bne (increase osteoclast activity)

2. resorption of Ca2+ from kidneys

3. stimulates kidneys to form calcitriol

4. calcitriol release enhances Ca2+ (and PO4³-) by GI tract

inhibitors: normal blood Ca2+

what is the hormone of the pineal gland?

melatonin

melatonin

stimuli: darkness

targets: various = secreted by pinealocytes from serotonin molecules

effects:

1. circadian rhythms (contribute to SAD)

2. inhibit reproductive functions (can reduce GnRH)

3. anti-oxidant in CNS (prevents free radical harm)

inhibitors: daylight

what are the 3 layers of the adrenal cortex (outer to innermost layer)

1. zona glomerulosa

2. zona fasciculata

3. zona reticularis

what is the hormone of the zona glomerulosa of the adrenal cortex

stimuli:

1. low Na+ in blood

2. low blood pressure and volume

3. K+ rise

targets: kidneys, pancreas, sweat glands, and salivary glands

effects:

1. electrolyte composition = conserve Na+

2. secondarily enhances osmotic reabsorption of water

3. increases salt receptor sensitivity

inhibitors: return to normal

what is the hormone of the zona fasciculata of the adrenal cortex

glucocorticoids (cortisol)

glucocorticoids (cortisol)

stimuli: ACTH

targets: liver, fat cells, and immune cells

effects:

1. glucose metabolism

2. secretes cortisol to increase glucose synthesis adn glycogen formation

3. fatty acids released and use proteins for energy

4. anti-inflammatory = reduces white blood cell activities

inhibitors: cortisol inhibits CRH (corticotropin-releasing hormone) and ACTH

what is the hormone of the zona reticularis of the adrenal cortex

androgens

androgens

stimuli: ACTH

effects:

1. small amounts of androgens released

2. stimulate pubic hair development before puberty

3. important for females post-puberty (muscle mass, blood cell production, and sex drive)

what are the 2 hormones of the adrenal medulla

1. epinephrine (adrenaline)

2. norepinephrine (noradrenaline)

epinephrine and norepinephrine

stimuli: sympathetic activation

targets: skeletal muscle, adipose, liver, and heart

effects:

1. skeletal = glycogen breakdown for ATP

2. adipose = fatty acid released for ATP

3. liver = glycogen to glucose for brain

4. heart = increased heart rate and force of cardiac muscle contraction

inhibitors: parasympathetic

4 things about the pancreatic islets

1. islet of langerhans = monitor blood glucose levels for direct effects

2. not enough blood glucose = release glucagon

3. blood glucose levels too high = release insulin

4. releases somatostatin (GH-IH) that suppresses glucagon and insulin

2 hormones created by the pancreatic islets of the pancreas

1. glucagon

2. insulin

glucagon

created by alpha cells

stimuli: low glucose levels

targets:

1. muscles and liver

2. adipose tissue

effects:

1. hydrolyzes glycogen into glucose for blood

2. use beta oxidation and glycolysis for energy (triglycerides)

3. create glucose from amino acids (gluconeogenesis)

4. overall = raise blood glucose levels

inhibitors: normal glucose and somatostatin (GH-IH)

insulin

created by beta cells

stimuli: high glucose levels

targets: pretty much everyone

effects:

1. increase glucose transporters in most cells

2. increase ATP production (activates glycolysis of enzymes)

3. absorbs and produces proteins

4. convert glucose to glycogen in muscle and liver

5. convert glucose to triglycerides

6. overall = lower blood glucose levels

inhibitors: normal glucose and somatostatin (GH-IH)

2 hormones of adipose

1. leptin

2. resistin

3 things about leptin

1. stimulates hypothalamus “I’m full”

2. now know many have defective leptin receptors

3. also can influence GnRH release so thin girls/women get periods later/irregular because lack of GnRH release

2 things about resistin

1. lowers insulin sensitivity

2. correlation with type II diabetes and obesity