Endocrine System Flashcards
exocrine glands
ducted glands that carry secretions to point of action
endocrine glands (2)
- ductless glands secrete into fluid filled extracellular space
- secreted product diffuses into lymphatics or blood vessels and carried through out body to place of action
hormones
biochemical function of secretory cells of endocrine gland/tissue which affects function of another cell
hormonal influence is dependent on? (2)
- specific hormone receptor binding interaction
- only affects specific target cells
steroid hormones (2)
- lipid based
- synthesized from cholesterol molecules in SMOOTH ER
non steroid hormones (3)
- synthesized from amino acids in ROUGH ER
- lipophobic molecule cannot diffuse across cell membrane
- located outer surface of cell membrane
prostaglandins (2)
- lipid based synthesized from fatty acids
- biochemical mediators produced by any cell in body (not erythrocytes)
neuro/endocrine system differences
hormones:
- slow acting
- long lasting
- widely influential (may affect nearly all body cells)
what is hormonal regulation most often under governance of?
negative feedback loop
negative feedback loop is?
stability
if loops REVERSES the original stimulus, system is negative feedback
positive feedback loop is? (3)
- explosive*
- if loop ENHANCES original stimulus, system is positive feedback
- produce unstable conditions
- often shut off by mechanism outside system
manners of control utilizing feed back loops (3)
- hypothalamic control
- nervous system control
- changes in blood composition/concentration control
location/structure: pituitary gland (4)
- bilobed/pea shaped
- found at base of brain in sella turcica of the sphenoid bone
- suspended from hypothalamus by infundibulum
- hypophyseal portal veins
hypothalamus control over pituitary gland (2)
- anterior pituitary hormones governed by neurosecretory cells secreted by hypothalamus.
- hormones travel directly to anterior pituitary gland via hypophyseal portal vein
anterior lobe of pituitary gland (2)
- larger anterior portion %75
- 5 types secretory epithelial tissue
posterior lobe of pituitary gland (2)
- smaller posterior %25
- pituicytes and neural tissue
function grow hormone (hGH, somatotropin)
hGH stimulates body growth/increases aspects of metabolism
anterior pituitary
prolactin (PRL)
with other hormones, initiates/sustains milk production by females developed mammary glands
thyroid stimulating hormone (TSH)
stimulates synthesis/secretion of two hormones produced by thyroid gland (T3,T4)
adrenocorticotropic hormone
- regulates production/secretion of adrenal gland’s cortical hormones
- melanocyte-stimulating hormone (MSH) governs skin pigmentation/brain activity
oxytocin (OT)
- enhances smooth muscle contractions in wall of uterus during delivery/softens symphysis pubis
- stimulates milk ejection
antidiuretic hormone (ADH, vasopressin) (3)
- decreases urine production by returning more water to blood stream
- absence of ADH pot. results in urine output increasing 10 fold
- elevates blood pressure by decreasing water loss
location/structure: thyroid gland (2)
- richly vascularized
- inferior to thyroid cartilage of larynx/anterior to trachea
thyroid follicles
spherical sacs whose follicular cells are responsible for synthesis and secretion of thyroid hormones
function of thyroid hormones (3)
- regulate oxygen use and basal metabolic rate (BMR)
- increase BMR by increasing rate of carbs, protein and lipid metabolism
- stimulates protein synthesis and use of fatty acids/glucose for ATP production
action of thyroid hormone calcitonin CT (2)
- decreases high blood calcium levels by inhibiting osteoclasts and stimulating osteoblasts
- negative feed back loop
parathyroid hormones (2)
- posterior surface of each lateral thyroid lobe superiorly and inferiorly
- 2 each lobe, 4 total
function of parathyroid hormone (PTH) (2)
- regulator of calcium homeostasis
- increases number/activity of osteoclasts stimulating bone reabsorption
structure/function: adrenal glands (2)
- richly vascularized pyramid shaped
- located superior portion of kidneys
adrenal medulla (2)
- smaller centrally located composed of modified sympathetic ganglion
- synthesizes catecholamines that intensify sympathetic ANS fight or flight response (prepares body for energy expending activity)
adrenal cortex (2)
- larger peripheral region encircles medulla
- glomerulosa responsible for synthesis of mineralocorticoids (aldosterone)
glucocorticoids (2)
- adrenal cortex: fasciculata
- steroid hormones regulating metabolism/resistance to stress (cortisol)
mineralocorticoids (2)
- adrenal cortex: glomerulosa
- aldosterone: increases sodium absorption/potassium excretion raising blood pressure
androgens (2)
- weak steroid hormones affecting early developmental physiology/aspects of reproduction
- most significant prepubescent/postmenopausal years
pancreas (2)
- digestive organ serving endocrine and exocrine functions
- posterior to stomach, connected to digestive tract by ducts
- %99 exocrine cluster cells
- %1 endocrine pancreatic islets
pancreas endocrine cells
- Alpha A cells: synthesize/secrete glucagon
- Beta B cells: synthesize/secrete insulin
function of glucagon
- elevate low blood glucose levels
- acts on liver cells
function of insulin
-decrease high blood glucose levels
pineal gland (3)
- attached to thalamus
- secretes melatonin in response to retina stimulation
- established bodies biological clock
pituitary gland: diabetes insipidus (DI)
- dehydration due to excessive urine formation attributed to ADH deficiency/hypo-secretion
- high volumes of urine
pituitary gland: pituitary dwarfism
abnormally slow growth/short stature with normal body proportions
pituitary gland: pituitary gigantism
abnormally rapid growth/tall stature with normal body proportions
pituitary gland: acromegaly
abnormal enlargement of extremities due to hyper secretion of hGH during adulthood
thyroid gland: graves disease (hyperthyroidism)
autoimmune condition body produces antibodies that mimic action of TSH, leading to hyper stimulation, goiter, elevated BMR
pancreas: diabetes mellitus
inability to produce/utilize insulin, leading to excessive blood glucose levels
adrenal glands: addison disease
- hyposecretory condition of adrenal cortex
- decreased release of glucocorticoids and aldosterone
cushings syndrome
excessive cortisol release attributed to adrenal adenoma
