Endocrine System Flashcards
secretion of hormone function
-chemical messengers/regulators which affect the activity of other cells
what results from endocrine glands being ductless?
-they secrete their products directly into the bloodstream
are endocrine glands vascular or avascular?
- vascular
- has very rich blood supply
characteristics of the effects on target tissues
- slow but long-lasting
- opposite of CNS & PNS
how is hormone secretion controlled?
- negative feedback mechanism
- neural control
what part of the brain controls the release of hormones?
- hypothalamus
- secretes substances called releasing factors
pituitary gland location
- inferior surface of brain
- attached to hypothalamus
- surrounded by circle of willis
pituitary gland structure components
- adenohypophysis
- neurohypophysis
pituitary gland adenohypophysis location
- anterior lobe
- glandular portion
pituitary gland adenohypophysis function
- produces and secretes six major hormones
- portal supply to anterior gland receives releasing factors
pituitary gland neurohypophysis location
- posterior lobe
- nervous portion
pituitary gland neurohypophysis nervous portion function
- stores and releases 2 hormones produced by hypothalamus
- dilated terminal axons that store hormone until neurons fire, releasing hormone into circulation
pituitary gland function
- “master gland” of the body
- regulates many of body’s activities by releasing specific hormones to impact other endocrine glands
pituitary gland is divided into what?
- anterior pituitary
- posterior pituitary
anterior pituitary gland hormones it secretes
- growth hormone
- thyroid stimulating hormone
- adrenocorticotropic hormone
- follicle stimulating hormone
- luteinizing hormone
- prolactin
posterior pituitary gland hormones it secretes
- oxytocin
- antidiuretic hormone
anterior pituitary: growth hormone
- GH
- increases protein synthesis and mitosis
- regulates growth of most cell sof the body
anterior pituitary: thyroid-stimulating hormone
- TSH
- regulates the hormonal activity of the thyroid gland
anterior pituitary: adrenocorticotropic hormone**
- ACTH
- controls the secretions of the hormones of the adrenal cortex
anterior pituitary: follicle stimulating hormone
- FSH
- stimulates follicle(ova) development in the ovary and sperm in testes
- stimulates sex hormone secretion
anterior pituitary: luteinizing hormone
- LH
- plays a role in ovulation
- stimulates secretion of sex hormones (estrogen and testosterone)
anterior pituitary: prolactin
-plays a role in secretion and production of milk from mammary glands(lactation)
posterior pituitary: oxytocin
- stimulates uterine and smooth muscle contractions
- promotes milk ejection from breast
posterior pituitary: antidiuretic hormone
- ADH
- affects permeability of kidney tubules to reduce the excretion of water
- secretes vasopressin
what does vasopressin control?
- controls BP
- constricts blood vessels
thyroid gland location
- anterior neck inferior to larynx
- surrounds anterior and lateral aspect of the trachea
thyroid gland gross structure
-two lobes connected by an isthmus
thyroid gland microscopic structure
- cuboidal cells: hormone production
- follicles: stores hormones
thyroid gland hormones it secretes
- thyroxine (T4)
- triiodothyronine (T3)
- calcitonin
thyroid gland: thyroxine and triiodothyronine site of action
-most cells of the body
thyroid gland: thyroxine and triiodothyronine effect
-regulates basal metabolic rate (BMR)
thyroid gland: calcitonin site of action
-bone
thyroid gland: calcitonin effect
- regulates osteoclast activity and therefore the amount of calcium which leaves bone
- lowers blood calcium levels
parathyroid gland location
-embedded on posterior side of thyroid gland
parathyroid gland structure
- 4 oval bodies
- ->two on superior poles, two on inferior poles
parathyroid gland hormone it secretes
-parathyroid hormone (PTH)
parathyroid gland: parathyroid hormone site of action
- increased osteoclastic activity in bone
- increased kidney reabsorption of Ca++
- increased dietary calcium ingested from intestine
parathyroid gland: parathyroid hormone effect
-increased blood calcium levels
adrenal glands location
- paired glands
- located on superior pole of the kidneys
adrenal glands structure
- adrenal medulla
- cortex
adrenal glands: adrenal medulla structure
- inner portion
- activated by stress
- prepares body for sympathetic ANS
adrenal glands: adrenal medulla hormone it secretes
-epinephrine (catecholamines)
adrenal glands adrenal medulla: epinephrine site of action
-many organs and tissues
adrenal glands adrenal medulla: epinephrine effect
-reinforces and prolongs sympathetic ANS response (inc. heart rate and respiration)
adrenal glands: cortex structure
- outer portion
- produces cortico-hormones
- responds to ACTH stimulation
adrenal glands: cortex hormones it secretes
- aldosterone
- cortisol/hydrocortisone (glucocorticoid)
- androgens (estrogen/progesterone)
adrenal glands cortex: aldosterone site of action
-kidney tubules
adrenal glands cortex: aldosterone effect
-regulates Na and K levels
adrenal glands cortex: cortisol/hydrocortisone site of action
-various tissues
adrenal glands cortex: cortisol/hydrocortisone effect
- regulates metabolism(glucose)
- prevent/reduces inflammation
adrenal glands cortex: androgens site of action
-various tissues
adrenal glands cortex: androgens effect
- supplement gonadal hormones
- promotes development of secondary sex characteristics
pancreas loaction
- upper abdomen
- posterior and inferior to stomach
pancreas structure
- endocrine portion (has islet of langerhans)
- exocrine portion
pancreas endocrine portion hormones secreted
- insulin (beta cells)
- glucagon (alpha cells)
pancreas endocrine portion: insulin site of action
-all body cells
pancreas endocrine portion: insulin effect
-regulates transport of glucose into cells
pancreas endocrine portion: glucagon site of action
-liver
pancreas endocrine portion: glucagon effect
-promotes conversion of glycogen into glucose
pancreas exocrine portion function
- consists of cells and ducts
- produces digestive enzymes into duodenum of small intestine
pineal gland location
-suspended from roof of 3rd ventricle
pineal gland hormones secreted
-melatonin
pineal gland melatonin site of action
- receives and responds to input from the visual pathway
- highest level at night
- affects sleep/wake cycle(circadian rhythms)
pineal gland melatonin effect
- inhibits hypothalamus stimulation of hormones which stimulate glands
- delays sexual maturation
gonads components
- ovaries
- testes
gonads ovaries structure
-follicle and corpus luteum
gonads ovaries hormones secreted
-estrogen/progesterone
gonads ovaries: estrogen site of action
-female reproductive organs (uterus)
gonads ovaries: estrogen effect
- development of gametes (egg) and regulation of female reproductive organs
- secondary sex characteristics
gonads testes structure
-interstitial cells of leydig
gonads testes hormones secreted
-testosterone
gonads testes: testosterone site of action
-male reproductive organs
gonads testes: testosterone effecr
- development of gametes(sperm) and regulation of male reproductive organs
- secondary sex characteristics
