A&P 2 collin college exam 1 endocrine and reproductive system

peptide hormones

chains of a.a; most are synthesized as prohormones

eicosanoids: prostaglandins

coordinate local cell activities

down regulation

presence of hormones triggers a decrease in the number of receptors

up regulation

absence of hormones triggers an increase in the number of receptors

paracrine communication

chemical signals transfer information from cell to cell within a single tissue

autocrine communication

messages affect the same cells that secrete them

example of autocrine communication

prostaglandins secreted by smooth muscle cells cause same cells to contract

endocrine communication

release hormones that are transported in bloodstream which alters the metabolic activities of organs

target cells

have receptors needed to bind and "read" hormonal messages; hormones go everywhere, but only these respond

functions of hormones

change types, quantities, or activities of enzymes and structural proteins in target cells

can alter metabolic activities of many tissues and organs at once

affect long-term processes like growth and development

hypothalamus function

produce ADH, OXT, and regulatory hormones

anterior pituitary function

produce and release ACTH, TSH, FHS, LH, GH, PRL, and MSH

posterior pituitary function

store and release OXT and ADH

pineal function

produce and secrete melatonin

parathyroid function

produce and release PTH

thyroid function

produce and release T3, T4, and CT

adrenal cortex function (zona glomerulosa)

produce and release mineralocorticoids (aldosterone)

adrenal cortex function (zona fasciculata)

produce and secrete glucocorticoids (cortisol)

adrenal cortex function (zona reticularis)

produce and release androgens (testosterone, estrogens)

adrenal medulla function

produce and release catecholamines (E and NE)

pancreas function

produce and release insulin and glucagon

endocrine system

all cells and tissues that make hormones/paracrines which release secretions into extracellular fluid

amino acid derivatives

same bases of a.a, but one chemical is changed

prohormones

inactive molecules converted to active hormones before/after they are secreted

lipid derivatives: eicosanoids

from arachidonic acid

eicosanoids: paracrines

coordinate cell activities and affect enzymatic processes

lipid derivatives: steroid hormones

all from cholesterol; bound to specific transport proteins in plasma-->stay in circulation longer than peptide hormones

direct communication

exchange of ions and molecules between adjacent cells of the same type across gap junctions

catecholamines and peptide hormones

are not lipid soluble and cannot penetrate cell membrane so they bind to receptor proteins on outer surface

steroid and thyroid hormones

are lipid soluble so they can diffuse across the cell membrane and bind to intracellular receptors

pituitary gland location

within in sella turcica, inferior to hypothalamus connected via infundibulum

tropic hormones

TSH, ACTH, FSH, LH

non-tropic hormones

GH, PRL, MSH

TSH

stimulates thyroid gland to produce calictonin, thyroxine, and triiodothyronine

ACTH

stimulates adrenal gland to produce mineralocorticoids, glucocorticoids, androgens, and catecholamines

FSH and LH

induce ovulation and stimulate secretion of estrogens and progesterone

stimulates production of androgens

GH

stimulates muscles, bones, and others to grow

prolactin

stimulates production of milk from mammary glands

OXT

stimulates uterine contractions during labor and milk production after birth

ADH

targets kidneys to not release water in urine, especially when dehydrated

thyroid gland location

inferior to larynx

thyroglobulin

protein synthesized by follicle cells, secreted into colloid of thyroid follicles

thyroxine

higher in blood; has 4 iodine atoms

triiodothyronine

has 3 iodine atoms

calcitonin

lowers blood calcium; stimulates calcium excretion by kidneys, prevents calcium absorption by digestive tract

parathyroid gland location

on back of thyroid gland

PTH

increases blood calcium level via chief cells: stimulates osteoclasts so they break down bone and release calcium into the blood

adrenal gland location

atop kidneys

aldosterone

increases blood sodium and decreases blood potassium levels

cortisol

increases blood glucose, have anti-inflammatory effects by suppressing immune system

androgens

sex hormones of males and females

epinephrine and norepinephrine

induce fight-or-flight reflexes; increase heart rate, muscles contractions, and glucose levels

pineal gland location

back of brain: posterior part of roof o 3rd ventricle

melatonin

regulates sleep/wake cycle, inhibit reproductive functions, protect against damage by free radicals (good immune system)

pancreas location

exocrine: acinar cells

endocrine: islets of langerhans

insulin

secreted by beta cells; stimulates transport of glucose into target cells--> lowers blood glucose levels

glucagon

secreted by alpha cells; stimulates glycogen break down and glucose release by liver--> raises blood glucose levels

general adaptation syndrome

"stress reponse"; 3 phases: alarm, resistance, exhaustion

alarm phase

epinephrine and norepinephrine

immediate response where energy reserves are mobilized and the body prepares for fight-or-flight responses

epinephrine is dominant

resistance phase

cortisol and aldosterone

occurs if stress is more than a few hours where lipids and a.a's are mobilized for energy and glucose is conserved for use by nervous tissues

glucocorticoids are dominant

exhaustion phase

starts when homeostasis regulation breaks down

aldosterone causes lower potassium levels

failure of 1+ organ systems is fatal

secondary endocrine organs

heart, kidneys, thymus, ovaries

heart

produce natriuretic peptides

when blood volume becomes excessive, blood volume and BP decrease

kidneys (hormones)

calcitriol: precursor of vitamin D, stimulates calcium and phosphate ion absorption

erythropoietin: stimulates marrow to make RBCs

kidneys (enzyme)

renin: converts angiotensinogen to angiotenisin 1

thymus

produces thymosin(blend of several hormones)

increases development and maturation of T lymphocytes

ovaries

produce estrogens

after ovulation, follicle cells reorganize into corpus luteum, and release estrogens and progesterone

gonads

organs that produce gametes and hormones

ducts

recieve and transport gametes

reproductive tract

all chambers and passageways that connect ducts to exterior of body

order of ducts sperm goes through

epididymis, ductus deferens, ejaculatory duct, urethra

accessory glands of male reproductive system

seminal glands, prostate, bulbo-urethral glands

scrotum

sac of skin and superficial fascia

hangs outside body

cremaster muscle

bands of skeletal muscle that elevate and pull testes closer to the body

dartos muscle

smooth muscle, wrinkles scrotal skin

temperature that testes is kept at

about 3°C lower than core body temperature.

testes

produce sperm and testosterone; house ducts

tunica vaginalis

outer layer derived from peritoneum

tunica albuginea

inner layer; fibrous capsule

pampiniform venous plexus

surround each testicular artery

spermatic cord

encloses nerve fibers, blood vessels, and lymphatics that supply testes

sperm conveyed from

seminiferous tubules-->rete testes-->efferent ductules-->epididymis

seminiferous tubules

thick, stratified epithelium surrounding central fluid-containing lumen

site of spermatogenesis

spermatogonia

produce 2 daughter cells, divided by mitosis

primary spermatocyte

begin meiosis and form secondary spermatocytes

secondary spermatocyte

differentiate into spermatids

spermatids

immature gametes

sertoli cells

nurture and help the development of spermatozoa

sertoli cells functions

1. maintin blood-testis barrier

2. support mitosis and meiosis

3. support spermatogensis

4. secrete inhibin

5. secrete androgen-binding protein

spermatozoon head

holds DNA; have enzymes that enable sperm to penetrate egg

spermatozoon midpiece

metabolic region; holds mitochondria which produces ATP needed to move tail

spermatozoon tail

locomotor region; flagellum

spermatozoa

detach from nurse cells, free in lumen of seminiferous tubules, are functionally immature

epididymis

start of male reproductive tract; has head, body, and tail

epididymis functions

1. monitors and adjusts fluid produced by seminferous tubes

2. recycles damaged spermatozoa

3. stores and protects spermatozoa: facilitates functional maturation

capacitation

1. sperm becomes motile when mixed with secretions of seminal glands

2. sperm become able to fertilize when exposed to pH of female organs in reproductive tract

ductus deferens

starts at tail of epididymis as part of spermatic cord, ascends through inguinal canal

lumen enlarges int ampulla

ductus deferens functions

carry ejaculatory sperm out of epididymis

ejaculatory duct

short passageway at junction of ampulla and seminal gland duct; penetrates wall of prostate gland, empties into urethra

urethra

extends from urinary bladder to tip of penis

3 regions: prostatic, membranous, spongy