endocrine system

how does the endocrine system act with the nervous system

coordinate and integrate activity of body cells

how does the endocrine system influence metabolic activities

via hormones

what is the response of the endocrine compared to nervous system responses

slower but longer lasting

what does the endocrine system control and integrate

reproduction; growth and development; maintain blood electrolyte, water, and nutrient balance; cellular metabolisms and energy balance regulation; mobilization of body defenses

two glands in the endocrine system

exocrine and endocrine

t or f: the endocrine glands are not part of the endocrine system

f, the exocrine glands are not part of the endocrine system

exocrine glands

produces non-hormonal substances and has ducts that carries secretion to membrane surface

endocrine glands

produce hormones and don’t have ducts

what are the endocrine glands

pituitary, thyroid, parathyroid, adrenal, pineal

what glands are both exocrine and endocrine

pancreas, gonads, placenta

which organ is considered a neuroendocrine organ

hypothalamus

what are the chemical messengers of the endocrine system

hormones, autocrines, and paracrines

hormone chemical messengers are

long-distance chemical signals

what do hormones chemical messengers travel in

blood or lymph

autocrine chemical messenger

exerts effects on secreting cells

paracrines chemical messengers

affect local cells other than secreting cells

two classes of hormones

amino acid-based hormones and steroids

how do hormones circulate in body

circulate via blood and affect cells with hormone receptors

target cells

tissues with specific hormone recepters

what can a hormone cause a target cell to do

alter the plasma membrane permeability and/or membrane potential, stimulate enzymes or proteins, activate/deactivate enzymes, induce secretory activity, and stimulate mitosis

how do hormones act

chemical nature and receptor location based

what are water soluble hormones

amino acid-based hormone (except thyroid)

can water soluble hormones enter the cell

not without a second messenger

lipid soluble hormones

steroid and thyroid

can lipid soluble hormone directly enter the cell

yes

what are the 2 main second messenger systems

cylcic-AMP and PIP2-calcium

steps of cyclic-AMP

1. hormone binds to receptor
2. receptor activates a g protein
3. g protein activates/inhibits adenylate cyclase
4. adenylate cyclase converts ATP to cAMP
5. cAMP activates protein kinases that phosphorylates other proteins
6. phosphorylated protein is either activated or inactivated
7. cAMP is rapidly degraded by phosphodiesterase and stops cascade
8. cascade has huge amplification effect

steps of PIP2-calcium

1. cahormone triggered g protein activates an enzyme called phospholipase-C
2. activated phospholipase-C splits membrane protein PIP2- into 2 second messengers:


1. diacylglycerol (DAG): activate protein kinase
2. inositol triphosphate (IP3): cause Ca2+ to release from intracellular storage
3. the Ca2+ ion that was released acts as another second messenger

what can Ca2+ do once released from PIP2-calcium

alter enzyme activity and channel, or bind to regulatory protein calmodulin

what can calmodulin do

activate enzymes that amplify cellular response

what happens when lipid soluble hormones and thyroid hormones diffuse into target cells

they bind to intracellular receptors, specifically the DNA region and it initiates DNA transcription which leads to mRNA

blood levels of hormones is controlled by a ___ feedback system

negatince

what happens if there is an increase hormone effect

target organs can inhibit hormone release

what is hormone synthesis and release triggered by

endocrine gland stimuli and nervous system

what are the 3 types of endocrine gland stimuli

humoral, neural, and hormonal stimuli

humoral stimuli

an ion and nutrient change in blood directly stimulates hormone secretion

neural stimuli

nerve fibers stimulate a hormone release

hormonal stimuli

hormones stimulate other endocrine organs to release hormones

t or f: nervous system can adjust the hormone levels when needed

t: called nervous system modulation

what can the nervous system modify in nervous system modulation

modify endocrine gland stimulation or inhibition

what must target cells have for hormone binding

specific receptors

what does target cell activation depend on

hormone blood levels, relative number of receptors on/in target cell, receptor and hormone binding strength

hormone amount can influence receptor ____ for that hormone

number

up-regulation

low hormone levels = more target cell receptors

down-regulation

high hormone levels = less target cell receptors

what two ways can a hormone circulate

free or bound

what type of hormones circulate the body attached to something

steroids and thyroid hormones

what do steroid and thyroid hormones attach to circulate

plasma proteins

circulating hormone concentrations reflects

rate of release and the speed it is inactivated and removed from body

how are hormones removed from blood

degrading enzymes, kidneys, liver, half-life

half-life

time it takes for homeone blood level to decrease by half

what are hormones response times

some immediate, hours-days, or inactive until they enter the cell

half-life, onset, and hormone activity duration depends on

if hormone is water or lipid soluble

what type of hormone is removed from the body the fastest

water soluble hormone

what type of hormone is removed from the body the slowers

lipid soluble hormone

t or f: can multiple hormones act on the same target at the same time

true

permissiveness

hormone can’t exert effects without the another hormone (dependent on one another)

synergism

more than 1 hormone can produce the same effect on a target cell

antagonsim

hormone opposes action of another hormone (opposite of each other)

what does the pituitary gland connect to

hypothalamus

how is the pituitary gland connected to the hypothalamus

through infundibulum and blood

posterior pituitary

neural tissue that directly attaches to hypothalamus via infundibulum

posterior lobe secretes

oxytocin and ADH

oxytocin

stimulates uterine contractions that are released during childbirth (positive feedback)

ADH (antidiuretic hormone)

targets the kidneys so they can reabsorb more water and prevent urine formation

what happens if the osmoreceptors in hypothalamus read the solute concentrations are too high

posterior pituitary secretes ADH

anterior lobe

glandular tissue that vascularly connects to hypothalamus via blood (hypophyseal)

anterior lobe secretes

growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, luteinizing hormone, and prolactinew

hat are the 4 tropic hormones

thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulating hormone, and luteinizing hormone

growth hormone

affects metabolism directly and growth promotion indirectly

direct metabolic actions of growth hormone

decrease cell glucose uptake and metabolism, trigger liver glycogen break down into glucose, increase fatty acid blood level for fuel and encourage cellular protein synthesis

indirent growth actions of growth hormone

triggers insulin-like growth factors and stimulate the cell nutrient uptake and collagen formation and deposition of bone matrix

what stimulates growth hormone release

growth hormone-releasing hormone (GHRH)

what is grwoth hormone-releasing hormone triggered by

low blood growth hormone or sugar and high amino acid-levels

what inhibits the release of growth hormone

growth hormone-inhibiting hormone (GHIH)

what triggers growth hormone-inhibiting hormone

increase growth hormone and insulin like growth factors

growth hormone hypersecretion causes

gigantism (kids) acromegaly (adult)

hyposecretion of growth hormone

pituitary dwarfism in kids

thyroid-stimulating hormone

stimulate normal thyroid development and secretion

release of thyroid-stimulating hormone is triggered by

thyrotropin-releaseing hormone

adrenocorticotropic hormone

stimulates adrenal cortex to release corticosteroids

adrenocorticotropic hormone release is triggered by

corticotropic-releasing hormone

wich 2 tropic hormone are gonadotropins

follicle-stimulating hormone and luteinizing hormone

follicle stimulating hormone and luteinizing hormone are secreted by

gonadotropic cells

follicle stimulating hormone stimulates

gamene productionl

luteinizing hormone promotes production of

goandal hormone

in females, luteinizing hormone

help mature egg follicles and triggers ovulation and release of estrogen and progesterone

in males, luteinizing hormone

stimulate production of testosterone

luteinizing hormone and follicle stimulating hormone are absent in the blood of

pre-pubescent children

prolactin

stimulates milk production

regulation of prolactin is controlled by

prolactin-inhibiting hormone

thyroid gland

regulates the body’s metabolic rate and growth and development

thyroid gland contains

follicles, colloid, and parafollicular cells

follicles

hollow epithelial cells that produce thyroglobulin

colloid

fluid that contain thyroglobulin and iodine

parafollicular cells

produce hormone calcitonin

thyroid hormone is the body’s ____ hormone

major

what are the 2 forms of thyroid hormone

t4 (thyroxine) and t3 (triiodothryonin)

t4 consists of

2 tyrosine molecules with 4 iodine atoms

t3 consists of

2 tyrosines with 3 iodine atoms