Chapter 17: Endocrine System Flashcards
Endocrine system
composed of ductless glands that synthesize and secrete hormones
the endocrine system has _______________ processing and causes _______________ changes
long-term processing/long-lasting
hormones are ____________ messengers that are called ____________
chemical/ligands
target cells
have the specific receptors for a hormone; are the destinations for hormones
endocrine glands lack ________ unlike exocrine glands
ducts
hormones molecules are transported within the blood from the endocrine gland’s associated capillaries by the ____________________________ to all body tissues
cardiovascular system
general functions of the endocrine system
- regulating development, growth, and metabolism
- maintaining homeostasis of blood composition and volume
- controlling digestive processes
- controlling reproductive activities
endocrine system regulating development, growth, and metabolism
- embryonic cell division and differentiation
- metabolism
endocrine system maintaining homeostasis of blood composition and volume
- blood solute concentration
- blood volume, cellular concentration, and platelet number
endocrine system controlling digestive processes
secretory processes and movement of materials in the digestive tract
endocrine system reproductive activities
development and function of reproductive systems and the expression of sexual behaviors
endocrine glands contain ____________ tissue that makes and releases hormones within a ___________ tissue framework
epithelial/connective
3 types of endocrine reflexes
1- hormonal stimulation
2- humoral stimulation
3- nervous system stimulation
hormonal stimulation
most common; a gland cell releases its hormone when some other hormone binds to it
humoral stimulation
most common; negative feedback based on the conditions of the fluid around it
nervous system stimulation
neuroendocrine reflex that’s triggered by the NS and finished by the endocrine system
circulating hormones include
- steroids
- biogenic amines
- proteins
steroids
lipid-soluble molecules synthesized from cholesterol
biogenic amines
- modified amino acids/ amino acid derivative
- water-soluble except for thyroid hormone (TH)
proteins
- water-soluble chains of amino acids
- amino acids are the building blocks
- most hormones are in this category
steroids include
- gonad steroids (estrogen, progesterone, and testosterone)
- steroids synthesized in the adrenal cortex (cortisol)
biogenic amines include
- thyroid hormone (TH)
- melatonin
- norepinephrine
- epinephrine
proteins include
- insulin
- glucagon
biogenic amines and proteins must bind to ____________________________ of their target cell and rely on ____________________________ inside the cell to finish their message
extracellular receptors/second messengers
local hormones
paracrine factors; don’t go far and stay in the interstitial fluid
local hormones include
- eicosanoids
- prostaglandins
eicosanoids
a type of local hormone formed from fatty acids with the phospholipid bilayer of the membrane
prostaglandins
are eicosanoids; stimulate pain and inflammatory responses; interleukin
lipid-soluble hormones
can diffuse across target cell membranes; are small, nonpolar, and lipophilic
water-soluble hormones
use extracellular membrane receptors; are polar and can’t diffuse across the membrane
hormone interactions on a target cell
- synergistic interactions
- permissive interactions
- antagonistic interactions
synergistic interactions
hormones work together to produce a greater effect
permissive interaction
first hormone allows action of second hormone
antagonistic interaction
one hormone cause opposite effect of another hormone
hypothalamo-hypophyseal tract
the hypothalamus produces the antidiuretic hormone and oxytocin, which is released into the posterior pituitary gland; somas in supraoptic nucleus and paraventricular nucleus
supraoptic nucleus
produces ADH
paraventricular nucleus
produces oxytocin
antidiuretic hormone (ADH)
water conserving hormone:
- decrease urine production
- stimulate thirst
- constrict blood vessels
oxytocin
- uterine contraction
- milk ejection
- emotional bonding
hypothalamo-hypophyseal portal system
blood vessels connects hypothalamus to anterior pituitary; contains the:
- primary plexus
- secondary plexus
- hypophyseal portal veins
the hypothalamo-hypophyseal portal system (anterior pituitary) produces 6 hormones
1- follicle stimulating hormone (FSH)
2- thyroid stimulating hormone (TSH)
3- growth hormone (GH)
4- prolactin (PRL)
5- adrenocorticotropic hormone (ACTH)
6- luteinizing hormone (LH)
hypothalamus releasing hormones
- thyrotropin-releasing hormone
- prolactin-releasing hormone
- gonadotropin-releasing hormone
- corticotropin-releasing hormone
- growth hormone-releasing hormone
hypothalamus inhibiting hormones
- prolactin-inhibiting hormone
- growth hormone-inhibiting hormone
primary plexus
porous capillary network associated with hypothalamus
secondary plexus
capillary network associated with anterior pituitary
hypophyseal portal veins
drain primary plexus and transport to secondary plexus
thyroid-stimulating hormone (TSH)
- released triggered by TRH
- causes release of TH from thyroid gland
prolactin (PRL)
- release triggered by PRH
- inhibited by PIH
- causes milk production, mammary growth
adrenocorticotropic hormone (ACTH)
- release triggered by CRH
- causes the release of corticosteroids by the adrenal cortex> glucocorticoids
follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
- release triggered by GnRH
- in female: regulate ovarian development and secretion of estrogen/progesterone
- in male: sperm development and secretion of testosterone
growth hormone (GH)
- causes liver to secrete insulin-like growth factors (IGF)
- GH and IGF function synergistically to stimulate cell growth and division
- target muscles, bones, liver, and adipose connective tissue
amount of GHRH released from the hypothalamus impacted by
- persons age
- time of day
- nutrient levels
- stress
- exercise
glycogenolysis
- breakdown of glycogen into glucose
- stimulated by GH, TH, cortisol, and glucagon
- inhibited by insulin
- releasing fuel
gluconeogenesis
- conversion of nutrients to glucose
- stimulated
- making a new glucose molecule
glycogenesis
- synthesis of glycogen
- inhibited with glucagon, cortisol, TH, and GH
- stimulated with insulin
- storing fuel
lipolysis
- breakdown of triglycerides
- stimulated
- increased, releasing fuel
lipogenesis
- formation of triglycerides
- inhibited with GH, cortisol, glucagon and TH
- stimulated with insulin
pituitary dwarfism
inadequate GH production
pituitary gigantism
over secretion of GH
acromegaly
excessive GH production after epiphyseal plates have closed
isthmus
midline between left and right lobes of the thyroid gland
follicular cells
cuboidal epithelial cells that surround a central lumen, synthesize thyroglobulin (TGB); makes TH
follicle lumen houses ___________
colloid
colloid
a viscous, protein-rich fluid
parafollicular cells
cells between follicles, make calcitonin
calcitonin
hormone that decreases blood calcium levels
hypothalamus releases _____ to the anterior pituitary that releases _______ to the follicular cells within the thyroid which releases _______
TRH/TSH/TH
follicular cells release 2 forms of TH to the blood
T3 and T4 which are transported to the blood through carrier molecules
process of release of T3 and T4
1- iodide ion uptake
2- iodine molecule formation and thyroglobulin synthesis
3- endocytosis
4- release of T3 and T4 from thyroglobulin
5- release of T3 and T4 into the bloodstream
effects of thyroid hormone
- cellular transport brings TH into target cells, binds the receptor
- TH increases metabolic rate and protein synthesis in targets
- stimulates increased amino acid and glucose uptake
- fosters energy (ATP) production
calorigenic
- generates heat
- raises the temperature
- it tells cells to use energy
hyperthyroidism
- results from excessive production of TH
- increased metabolic rate, weight loss, hyperactivity, heat intolerance
- caused by T4 ingestion, excessive stimulation by the pituitary, or loss of feedback control in the thyroid
graves disease
- too much TH
- formation of autoantibodies that mimic TSH
- autoantibodies bind to TSH receptors on follicular cells causing an abnormally high production of TH
hypothyroidism
- results from decreased production of TH
- low metabolic rate, lethargy, cold intolerance, weight gain
- caused by decreased iodine intake, loss of pituitary stimulation of the thyroid, postsurgical, or immune system destruction of the thyroid
goiter
- enlargement of thyroid
- typically due to insufficient dietary iodine
- lack of dietary iodine preventing thyroid from producing thyroid hormone
calcitonin
- synthesized and released from parafollicular cells of thyroid gland
- stimulus for release is high blood calcium or stress from exercise and acts to decrease blood calcium levels by:
1- inhibiting osteoclast activity
2- stimulate kidneys to increase excretion of calcium in urine
adrenal medulla
- forms inner core of each adrenal gland
- releases epinephrine and norepinephrine with sympathetic stimulation
adrenal cortex
- synthesizes corticosteroids
- three regions producing different steroid hormones:
1- zona glomerulosa
2- zona fasciculata
3- inner zona reticularis
zona glomerulosa
- thin, outer cortical layer
- mineralocorticoids made here (aldosterone)
mineralocorticoids
hormones that regulate electrolyte levels
aldosterone
fosters Na+ retention and K+ secretion; increases BP
zona fasciculata
- larger, middle cortical layer
- glucocorticoids made here (cortisol)
glucocorticoids
hormones that regulate blood sugar
cortisol
increases blood sugar (during stress) and decreases immune system (inflammation)
zona reticularis
- thin, inner cortical layer
- gonadocorticoids made here (androgens)
gonadocorticoids
sex hormones
androgens
male sex hormones made by adrenals and converted to estrogen in females
effects of cortisol
- liver cells increase glycogenolysis and gluconeogenesis; decrease glycogenesis
- adipose cells increase lipolysis and decrease lipogenesis
- many body cells break down proteins to amino acids
- most cells decrease their glucose uptake, sparing it for the brain
cushing syndrome
- chronic exposure to glucocorticoid hormones
- obesity, hypertension, hirsutism, kidney stones, and menstrual irregularities
addison disease
- form of adrenal insufficiency
- develops when adrenal glands fail
- weight loss, fatigue and weakness, hypotension, and skin darkening
hypothalamus releases _______ to the anterior pituitary which releases ________ to the zona fasciculata in the adrenal cortex which releases _______
CRH/ACTH/cortisol
three stages of stress response
1- alarm reaction
2- stage of resistance
3- stage of exhaustion
alarm reaction
initial response involving the sympathetic nervous system activation, epinephrine and norepinephrine
stage of resistance
after the depletion of glycogen stores, the adrenal secretes cortisol (glucocorticoid) to raise blood sugar and help meet energy demands, long-lasting
stage of exhaustion
depletion of fat stores results in protein breakdown for energy, leading to the weakening of the body and illness
pancreas has __________ and ___________ functions
endocrine and exocrine
glucagon
increase glucose in the bloodstream
the pancreas is made up of
- acinar cells
- pancreatic islets
acinar cells
- generate exocrine secretions for digestion
- make up the vast majority of pancreas as saclike acini
pancreatic islets
- contain clusters of endocrine cells
- alpha and beta cells
alpha cells
secrete glucagon; increases BP
beta cells
secrete insulin; decreases BP
diabetes mellitus
- inadequate uptake of glucose from blood
- chronically elevated glucose, blood vessels damaged
type 1 diabetes
- absent or diminished release of insulin by pancreas
- tends to occur in children and younger individuals
type 2 diabetes
- from decreased insulin release or insulin effectiveness
- obesity major cause in development
- tends to occur in older individuals, but can occur in young adults
gestational diabetes
seen in some pregnant women
hypoglycemia
- glucose levels below abnormal
- insulin overdose, prolonged exercise, alcohol use, liver or kidney dysfunction
- deficiency of glucocorticoids or GH, genetics
pineal gland
- small unpaired body in the epithalamus of the diencephalon
- secretes melatonin at night
- regulates circadian rhythm and has effects on mood
parathyroid glands
- small structures located on the posterior surface of the thyroid gland
- contain chief (principle) and oxyphil cells
chief (principal) cells
make PTH, which increases blood calcium and activates the calcitriol hormone
thymus
- epithelial cells secrete thymic hormones/thymosin
- located anterior to the top of the heart
endocrine tissue in heart atria secretes
atrial natriuretic peptide (ANP)
ADP
- released when BP is really high
- a hormone that decreases BP
kidney endocrine cells release
erythropoietin (EPO)
EPO
- produce more red blood cells
- secretion occurs in response to low blood oxygen
liver secretions include IGF and the inactive hormone ________________
angiotensinogen
angiotensinogen
- helps to increase BP
- converted to active angiotensin II by enzymes from the kidney bacteria
- angiotensin II helps raise BP when it starts to fall
stomach
secretes gastrin
gastrin
increases secretion and motility in stomach for digestion
