Endocrine System Flashcards
gland
specialized epithelial cell or cells that secrete a substance
exocrine glands
secrete their products into the body cavities in the lumen of an orang or the outer surface of the body
endocrine
secrete hormones directly into the interstitial fluid surrounding the gland - not in ducts
hormone
chemical produced in the body, secreted by the endocrine glands
is the mediator molecule that is released in one part of the body but regulates the activity of cells in other parts of the body
metabolism
refers to all chemical reactions occurring in the body
chemical reactions involve the making and breaking of bonds between atoms
necessary for body function to occur and body structures to be built
hypothalamus
“master” of the endocrine glands
skull - inferior to the thalamus
link between nervous and endocrine system
regulates all aspects of growth, development, metabolism, and homeostasis
hypothalamus function
produces oxytocin (OT) and antidiuretic hormone (ADH)
sends it to posterior pituitary for storage and released when needed
hormones control the anterior pituitary gland activity via releasing hormones
pituitary gland
was commonly referred to as the “master” gland
secretes several hormones that control other endocrine glands
located at the base of the cerebrum
two lobes (pituitary)
posterior (neurohypophusis) - two hormones synthesized by the hypothalamus
anterior - 7 hormones
posterior pituitary lobe
stores and releases 2 hormones that affect the body directly oxytocin and antidiuretic hormone
oxytocin
uterine contractions, mammary glands
antidiuretic hormone
controls urine output, raises blood pressure
anterior pituitary lobe
secretes seven hormones that regulate a wide range of bodily activities from growth to reporduction
human growth hormone (hGH)
hormone secreted by somatotrophin that stimulates body growth
prolactin (PRL)
initiates and maintains secretion of milk
melanocyte stimulating (MSH)
increase skin pigmentation in amphibians by stimulating the depression of melanin granules in melanocytes
gonad activity (FSH/LH)
secretes hormons that influence gonads in both male and female to secrete estrogen, progesterone, and testosterone
adrenalcortocotropic hormone (ACTH)
act on adrenal glands; various body functions blood pressure, glucose level, immune response, androgens
thyroid (TSH)
secretes hormones that stimulates the thyroid gland; metabolism rate
pineal gland
small pine cone shaped - attaches to the roof of the 3rd ventricle of the brain at the midline
secretes melatonin in response to visual input
biological clock, sleepiness
thyroid gland
butterfly shaped, highly vascular
located neck region inferior to the larynx (voice box)
releases hormones T3 (triiodothyronine) and T4 (tetra…)
calcitonin (CT) - thyroid
inhibits osteoclasts (bone breakdown cells) resulting in lowering blood calcium not regulated by ant pituitary - secretion is regulated by high blood CA
positive feedback
response enhances or intensifies the stimulus for example control labor contractions
mission accomplished
negative feedback
hormone secretion by glands controlled by the hypothalamus
when hormone level is too high
parathyroid glands
posterior, medial surface of the lateral lobes of the thyroid usually one superior and one inferior (round/ovoid)
release parathyroid hormone
regulates the level of calcium, magnesium, and phosphate ions that are circulating in our blood
parathyroid function
chief cells - more numerous and produce parathyroid hormone (PTH)
oxyphil cell - function unknown
thymus gland
located - medistinum
promotes a maturation of T-cells (a type of white blood cell that destroys microbes and foreign substances)
made of lymphatic tissue and functions as part of the lymphatic system
may retard the aging process
gonads - ovaries
located - pelvic cavity
regulate oocyte development, secrete hormones (estrogen and progesterone - at puberty promote secondary sex characteristics; enlargement of breast and the widening of hips)
gonads - testes
located - outside the abdominal cavity within the scrotum
regulates sperm production and testosterone (at puberty promotes secondary sex characteristics) and androgen
stimulates the descent of the testes
adrenal
located - superior poles of the kidneys
cortex and medulla
cortex function
secretes the hormones androgen, minerlocrticoids, and glucocrtic
zona glomerulosa
outer most layer secretes aldosterone (helps adjust BP and blood volume)
zona fasciculata
middle (widest) layer that is produces cortisol (reduces swelling by inhibiting immune reponses and raises blood glucose level
zona reticularis
deepest layer of the cortex that produce small amount of androgens (in both sexes, promotes axilla and pubic hair growth)
medulla function
secretes hormones epinephrine and norepinephrine (fight or flight)
pancreas
flattened organ consists of head body and tail serves as both an endocrine and exocrine gland
lies transversely in the abdomen between the kidneys and the duodenum of the small intestine (in the curve of the duodenum)
pancreas function (endocrine)
4 types of islets of langerhans cells alpha, beta, delta, F cells
alpha cells
17% secrete glucagon - hormone acts on liver to convert glycogen to glucose
beta cells
70% - secrete insulin - hormone acs on various cells of the body to accelerate glucose diffuse into cells
also to accelerate conversion of glucose into glycogen
delta cells
7% secrete somatostatin - identical to growth hormone inhibiting hormons secreted by the hypothalamus
f cells
remainder of the cells - secrete pancreatic polypeptide
