Quiz 10 - Endocrine Flashcards
overview of endocrine system
endocrine and nervous system cooperate together to maintain homeostasis
nervous - fast acting; specific
endocrine - slower, longer lasting effects
endocrine
- secretes hormone into the bloodstream
- no ducts
- glands are highly vascularized (great blood supply)
- secretions are hormones
exocrine
- secretes onto body epithelial surface
- secretions travel via ducts onto target organs
- secretions are usually fluids, lubricants and enzymes
- examples: sweat, sebum, saliva
endocrine cells
grandular secretory cells that release hormones
hormones
organized into four groups based on chemical structure:
- amino acid derivatives
- eicosanoids
- peptide hormones
- steroid hormones
peptide hormones
- amino acid chains (proteins)
- most hormones are peptides
- act much like a neurotransmitter receptor
- acts at the surface of the cell (on receptors)
steroid hormones
- cholesterol based (lipids)
- easily cross a cell membrane
- longer lasting effect
- act inside the cell
- activates or inhibits specific genes in nuclear DNA
3 mechanisms of Hypothalamus
- act as an endocrine organ itself by releasing hormones via posterior pituitary
- secretes regulatory hormones that control endocrine cells in anterior pituitary
- exerts direct neural control over adrenal gland
pituitary gland
located below hypothalamus, hangs off of infundibulum
posterior pituitary
controlled by nerves from hypothalamus
- produces ADH and oxytocin
target and effect of ADH
target - kidneys
effect - decreases urine secretion, vasoconstriction of blood vessels
target and effect of oxytocin
target - uterus; mammary glands
effect - lactation; labor contractions
anterior pituitary (function, secretion, target)
- controlled by the hypothalamus: regulates other endocrine glands
- secretion: hormones that regulate the growth and secretion
- target: other glands and numerous body tissues
7 hormones produces by anterior pituitary
- ACTH
- GH
- TSH
- prolactin
- FSH
- LH
ACTH
adrenocorticotropic hormone
activates adrenal cortex to produce glucocoricoids
GH
growth hormone
stimulates cell growth and replication (bone & muscle)
TSH
thyroid-stimulating hormone
targets thyroid gland
prolactin
stimulates and regulates breast tissue growth and milk production
gonadotropins
regulates sex organ activities
FSH
follicle-stimulating hormone
- promote oocyte development (via estrogen) in women
- stimulates sperm production in testes
LH
leutenizing hormone
- induces ovulation (via progesterone) in women
- stimulates androgens (testosterone) in men
thyroid gland
location/structure: anterior surface of trachea, largest purely endocrine gland in the body
produce/secrete: thyroid hormones (thyroxine and triiodothyronine) and C Cell hormone (calcitonin)
target and effect of thyroid hormones
target: almost all tissues of the body
effect: increase basal metabolic rate, increase O2 consumption, increase heat production, increase protein synthesis
target and effect of calcitonin
target: bone and kidney
effect: calcium retention
parathyroid gland (location, secretion, target, effect)
location - 4 pea-sized glands on posterior surface of thyroid, important for Ca homeostasis in human
secretion - parathyroid hormone (PTH)
target - bone, GI tract and kidneys
effect - increase Ca released into blood stream (bone), increase Ca absorption (GI), decreases Ca excretion in urine (kidney)
thymus gland (l, s, t, e)
location - posterior to sternum, rests on pericardial cavity
secretion - thymosin
target - lymphoid tissue
effect - increased lymphocyte production (immune system)
adrenal glands
location - attached to both kidneys
- outer = adrenal cortex
- inner = adrenal medulla
adrenal cortex
location - outermost layer (yellow due to lipids), produces more than 24 hormones called adrenocortical steroids, controlled by ACTH from the anterior pituitary
secretions of adrenal cortex
glomerulosa, fasciculata, reticularis
secretion, target and effect of glomerulosa
secretion - aldosterone
target - kidneys
effects - increase Na retention
secretion, target and effect of fasciculata
secretion - cortisol
target - liver and muscles
effects - increase glucose synthesis, increase glycogen formation
secretion, target and effect of reticularis
secretion - androgens
target - sex organs
effects - pubic hair development in adolescence, promote muscle mass and supports libido in women
location, secretion and effect of adrenal medulla
location - reddish-brown, due to high vascularity; controlled by SNS
secretion - epinephrine and norepinephrine
effect - increased cardiac activity, in creased blood pressure, release lipids from adipose tissue
pineal gland (l, s, t, e)
location - part of epithalamus, dorsal to hypothalamus; small, red, pinecone shaped
secretion - melatonin
targets - hypothalamus and anterior pituitary
effect - regulates circadian rhythms
