physiology chap 11 - endocrine

Endocrine System

Series of glands that produce hormones which act on specific targets

Hormones are what type of messengers

chemical

Most endocrine organs function in

other body systems

Non-steroid Hormones are

hydrophilic

Polypeptides are short chains (<100) of what

amino acids

Amine hormones

derivatives of the amino acids tyrosine and tryptophan

Glycoproteins

long chains of amino acids with ≥ 1 carbohydrate attached

what are steroid hormones derived from

the lipid

steroid hormones can pass through what

the cell membrane

Nuclear receptors have a

Ligand-binding domain

DNA-binding domain

Dimerization of receptors

Receptors bind to a hormone-response element of a target gene to stimulate gene transcription

Hormones that affect metabolism are often derived from

“less active” parent or precursor

Precursors are typically called

prohormones

prohormones are derived from

larger precursor molecules called prehormones

Synergistic effects

two or more hormones work together

Permissive effects

one hormones enhances (or increases) the responsiveness of a target organ to another hormone

Antagonistic effects

one hormone inhibits another

Priming

Upregulation of receptors to ensure hormone has a greater chance of action

Desensitizing

Downregulation of receptors typically due to continuous exposure to a hormone

what can prevent desensitization

Pulsatile secretion

Pituitary Gland is attached to what

hypothalamus

how is the pituitary gland attached

infundibulum

Anterior pituitary

epithelial in origin

posterior pituitary

neural in origin

what does the anterior pituitary release

tropic hormones

what do tropic hormones stimulate

other endocrine glands

what is the anterior pituitary gland controlled by

hypothalamus

what does anterior pituitary secrete

Releasing hormones

Inhibiting hormones

Growth Hormone (GH, Human growth hormone, or Somatotropin)

Stimulates mitosis (tissue growth), and increases in energy substrates in the blood

Acromegaly

Too much GH in adulthood

Dwarfism

Too little GH in childhood

Gigantism

Too much GH in childhood

What does Prolactin (PRL) stimulate

milk production in females

Prolactin-inhibiting hormone (PIH = dopamine) inhibits

prolactin secretion

Oxytocin and TRH thought to promote prolactin release when

dopamine decreases

Hormones are produced and regulated by the

hypothalamus

where are hormones stored

in the posterior pituitary

Hormones are transported to posterior pituitary via

hypothalamo-hypophyseal tract

When is Antidiuretic hormone (ADH, vasopressin) released

when sodium in blood is too concentrated

How does Antidiuretic hormone (ADH, vasopressin) raise your blood pressure

constricting blood vessels

Antidiuretic hormone (ADH, vasopressin) increase the permeability of what

the collecting ducts in the kidneys

Diabetes insipidus

decreased ADH) = produce copious amounts of urine

what does Oxytocin cause

uterine contraction and contraction of muscles of the mammary glands (milk ejection)

oxytocin is regulated by what

stretch of uterus, suckling

oxytocin is what type of feedback

positive

how many glands does the adrenal gland have

two

What does the cortex produce

many hormones (corticosteroids)

what are the 3 corticosteroids

Glucocorticoids, Mineralocorticoids, Gonadocorticoids

medulla consists of what

epinephrine, norepinephrine

Glucocorticoid production is stimulated by

ACTH

Cortisol

Functions to regulate glucose metabolism and the inflammation response (inhibits the immune system)

Mineralocorticoid

Mineralocorticoid production is stimulated through the renin-angiotensin-aldosterone system

Aldosterone

Functions to regulate H2O balance by conserving Na+ (K + excretion)

Gonadocorticoids

Weak androgens (DHEA) that are converted to small amounts of testosterone and estrogen

what does the Gonadocorticoids supplement

sex steroids secreted by gonads

What is Addison’s disease caused by

decreased mineralocorticoids and glucocorticoids, and excessive ACTH

what are the symptoms of Addisons disease

electrolyte imbalance (K+ and Na+), weakness, dehydration, weight loss, hypotension, hypoglycemia

Cushing’s syndrome is caused by what

increased secretion of ACTH

symptoms of cushings diseas

Changes in carbohydrate and protein metabolism, hyperglycemia, hypertension, muscular weakness

what does adrenal medulla produce

epinephrine and norepinephrine

what does the adrenal medulla function in

fight or flight

adrenal medulla stimulated bywhat

direct nerve stimulation from the sympathetic nervous system

where is the thyroid gland located

anterior neck just below the larynx

Thyroid hormone (TH) secreted by

thyroid follicles

Calcitonin secreted by

parafollicular cells

Thyroid hormone ——→

follicular cells

T4 and T3 cause an increase in

metabolism, thus increasing body temperature

Normal growth of many tissues dependent on

presence of thyroid hormones

Endemic goiter

insufficient iodine in diet

Hypothyroidism

Myxedema

Cretinism

Hyperthyroidism

Grave’s disease

Calcitonin makes what

parafollicular cells

Calcitonin is controlled by what

direct response to blood Ca2+ levels

Calcitonin functions to

decrease blood calcium

Parathyroid hormone (PTH) is what type of hormone

nonsteroid

Parathyroid hormone (PTH) controlled by what

direct response to blood Ca2+ levels

PTH causes what

increase in blood calcium

Exocrine gland

Produces pancreatic digestive juices

Endocrine gland

Consists of pancreatic islets that produce non-steroid hormones

what do alpha cells secrete

glucagon

what do beta cells secrete

insulin

what do delta cells secrete

somatostatin

Delta cells secrete somatostatin, which prevents release of

insulin and glucagon

Type I diabetes =

insulin-dependent diabetes mellitus

Type II diabetes

noninsulin-dependent diabetes mellitus

Thymus Gland produces what

thymosins

thymosins is what type of hormone

non-steroid

thymus gland functions in

immune system development

what does the pineal gland produce

melatonin

melatonin is what hormone

non-steroid

melatonin functions in the

seasonal and sleep/wake (circadian) cycle

Ovaries and Placenta Produce

estrogens and progesterone

Ovaries and Placenta functions in

development of primary and secondary sexual characteristics in women

Testes interstitial cells produce

androgens

what is the most predominant androgen

testosterone

testes function in

development of primary and secondary sexual characteristics in men

Paracrine and Autocrine Regulation most diverse group is what

prostaglandins

Paracrine and Autocrine Regulation play roles in what

Immune Reproductive Digestive Respiratory Circulatory Urinary