Endocrine System Flashcards
characteristics of endocrine system
-system of glands that secrete hormones into bloodstream
-controls body along with CNS
-organs located throughout body
-actions mediate all tissues
-only system whose organs are anatomically not connected
communication in ES
hormones
communication in NS
neurotransmitters
target in ES
any cell with receptors for hormones
target in NS
neurons, muscles, glands
recovery time in ES
slow
recovery time in NS
fast
effect of ES
metabolic activity, widespread, long lasting
effect of NS
contraction, secretion, localized, short-term
exocrine glands
-secretions (like sweat, saliva, etc.) transported by ducts
-located by target cells
endocrine glands
-secrete hormones
-no ducts, released directly into bloodstream
-located in highly vascular areas
hormones
-chemical triggers
-regulate metabolism
-need specific receptor on specific cell
target cells
cells with receptors for hormones
target organs
organs with target cells
amino-acid based hormones
-modified amino acids
-most common
-secreted via exocytosis, must have receptor
-elaborate rough ER
-act as hormones and neurotransmitters
steroid hormones
-type of lipid from cholesterol
-secreted by diffusion
-extensive smooth ER
-produced by gonads and adrenal cortex
humoral control of secretion
in response to changing levels of ions or nutrients in blood
neural control of secretion
stimulation by nerves
hormonal control of secretion
stimulation received from other hormones (tropic hormones)
positive feedback
-not common
-accelerates original process
-ex: action of oxytocin on uterine muscles during birth
negative feedback
-most common
-turn off or slow down original process
-ex: regulation of blood glucose level in body
phermones
-act outside body
-work on subconscious level
-apocrine glands
purely endocrine organs
-pituitary gland
-pineal gland
- thyroid gland
-parathyroid gland
-adrenal gland (cortex and medulla)
organs with target cells
-pancreas
-thymus
-gonads
-hypothalamus
-heart
-GI tract
-placenta
-skin
-kidney
pituitary gland
-in hypothalamus
-anterior: largest, Adenohypophysis, produces 7 hormones, 6 are tropic (Melanocyte-stimulating hormone is not tropic)
-posterior: neurohypophysis, storages 2 hormones (ADH and oxytocin)
thyroid gland
-anterior to trachea, inferior to thyroid cartilage
-largest
-highly vascularized
-produces hormones that control metabolism and calcium levels (thyroid and calcitonin)
-Iodine is needed to produce TH
parathyroid gland
-small, flattened, on posterior surface of thyroid gland
-most people have four
-secrete parathyroid hormone (increases blood Ca++ (calcium) concentration when it gets too low)
pineal gland
-in epithalamus
-gets smaller with age
-secretes melatonin, regulates circadian rhythm
adrenal gland
-on top of kidney
-suprarenal gland
-secretes 30 hormones, many steroid hormones
-epinephrine and norepinephrine
adrenal cortex
-secretes lipid based steroid hormones called corticosteroids
-mineralocorticoids, glucocorticoids, gonadocorticoids
adrenal medulla
-secretes epinephrine and norepinephrine
-preganglionic neuron synapses in gland
short-term stress
-NS
-acts on adrenal medulla
long-term stress
-ES
-acts on adrenal cortex
pancreas
-behind stomach in posterior abdominal wall
-contains acinar cells and islet cells
acinar cells
-most abundant in pancreas
-exocrine function
-secrete digestive enzymes
islet cells
-endocrine function
-secrete alpha and beta cells
alpha cells
-mostly on periphery
-secrete glucagon
-raise blood sugar
beta cells
-most abundant, located centrally
-secrete insulin
-lower blood sugar
diabetes
high blood sugar, not enough insulin, target cells don’t respond to insulin
thymus
-located deep to the sternum
-part of immune system
-gets smaller with age
-hormones stimulate maturation of lymphocytes
Acromegaly
Over secretion of GH as an adult
Dwarfism
not enough GH secreted
Hypothyroidism
Decreased production of TH
Hyperthyroidism
Excessive production of TH
Cushing syndrome
adrenal gland produces too many corticoids
Addison disease
adrenal failure to produce corticosteroids
