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Endocrine system

The body’s second great controlling system which influences metabolic activities of cells by means of hormones

Pituitary, thyroid, parathyroid, adrenal, and thymus

Endocrine glands

Homeostasis

Maintenance of the internal environment ( balance )

Metabolic regulation

Storage and use of energy substrates

Homeostasis

Metabolic regulation

Responses to external stimuli

Control of growth, reposition and development

Roles of endocrine system

Hormones

Chemical substance released by a group of cells to control the function of other types of cells

affect only specific target cell

\
affect many different types of cell

types of hormones

hypothalamus

has both neural function and releases hormones

adipose cell, pocket of cell in wall of the small intestine, stomach, kidney, and heart

other tissue and organs that produce hormones

at distance

hormones can exert their effect______ from their site of production

neurohormones

specialized neurons that secrete chemical into the blood rather than synaptic cleft

endocrine signaling

a cell targets a distant cell through the blood stream

paracrine signaling

cell target a nearby cell

autocrine signaling

cell target it self

multiple hormone system

play a key role in regulating almost all body function

blood stream

released into and carried via______ to target tissue

target cell

refers to a cell that contain specific receptors (binding sites) for a particular hormone

1. proteins and polypeptides
2. steroid
3. amino acid tyrosine

what are the three general classes of hormones

proteins and polypeptides

secreted by the anterior and posterior pituitary gland, the pancreas \`(insulin and glucagon), the parathyroid gland ( parathyroid hormone), and many others

steroid

secreted by the adrenal cortex ( cortisol and aldosterone ), the ovaries (estrogen and progesterone), the testes (testosterone), and the placenta (estrogen and progesterone)

amino acid tyrosine

secreted by the thyroid (thyroxine and triiodothyronine ) and the adrenal medulla (epinephrine and norepinephrine ). there are no known polysaccharides or nucleic acid hormones

peptide (protein) hormones

they can disolves in water (plasma)

steroid hormones

secretedby gonads, adernal cortex, placenta

\
derived from cholesterol

\
usually bound to **carrier** proteins

amine hormones

derived from aminoc acid tyrosine

\
they include the thyroid hormones epinephrine and norepinephrine (produced by the adrenal medulla) and dopamine (produced byh the hypothalamus)

nonsteroid hormones

first messenger

\
mechanism of action:

hormones recepetors interaction (first messenger)

enzyme activation

released of the second messenger

effect on cellular function

steroid

pass through the cytoplasm and enter nucleus where they bind with a receptor ( lock and key model )

receptors

region of tissue, or a molecule in a cell membrane, which responds specifically to a particular __neurotransmitter__, __hormone__, __antigen__, or other substance.

protiens

hormonal receptors are large _______

on the surface of cell membrane ( peptides and catecholamines)

\
in the cell cytoplasm ( steroid )

\
in the cell nucleus (thyroid hormones )

receptors location

the rate of secretion

\
the rate of its removal (metabolic clearance )

two factors control the concentration of a hormones in the blood

metabolic destruction by tissue

\
excretion by the liver into bile

\
excretion by the kidney into urine

hormones are cleared by

slow

clearance of protein-bound hormones is ________ than clearance of peptide hormones

negative feedback

\
positive feedback

blood level of hormones are controlled by feedback mechanisms

prostaglandins

powerful substances found in a wide variety of body tissue

pituitary gland

it is located in the diencephalon

diencephalon

where is pituitary gland locatedn

adenohypophysis

anterior lobe

neurohypophysis

posterior lobe

glandular tissue

what is adenohypophysis made up off

adenohypophysis

synthesize and secrete a number of hormones

neurohypophysis

receive, store and release hormones from the hypothalamus

infundibulum

is the stalk that connects the pituitary to the brain

posterior pituitary

is an extension of the neural tissue

anterior pituitary

is a true endocrine gland of epithelial origin

growth hormone (GH)

\
prolactin (PRL)

\
thyroid-stimulating hormone (TSH)

\
adrenocorticotropic hormones (ACTH)

\
follicle-stimulating hormone (FSH)

\
luteinizing hormones (LH)

the six hormones of the anterior pituitary

TSH

stimulates growth of the thyroid gland; also stimulates it to secrete thyroid hormone

ACTH

stimulates growth of the adrenal cortex and stimulates it to secrete glucocorticoids (mainly cortisol)

FSH

initiates growth of ovarian follicle each month in the ovary and stimulates one or more follicles to develop to the stage of maturity and ovulation

\
stimulates sperm production in the male

LH

acts with FSH to stimulates estrogen secretion and follicle growth to maturity

\
cause ovulation

GH

stimulates growth by accelerating protein anabolism

\
accelerates fat catabolism and slows glucose catabolism

PRL

stimulates breast development during pregnancy and secretion of milk the delivery of the baby.

adernal cortex

target tissue of ACTH

thyroid gland

target tissue of TSH

most tissue

target tissue of GH

gonads

target tissue of FSH

gonads

target tissue of LH

mammary glands and other sex accessory organ

target tissue or PRL

releasing and inhibiting hormones

hypothalamus neurons synthesize

ADH: supraoptic nuclei and Oxytocin:paraventricular

hypothalamus neruon cell bodies produced

vasopressin

ADH also known as

ADH and oxytocin

posterior pituitary homones

secretory vesicle and neurophysin

these hormones are synthesized in the neuron cell bodies in hypothalamus and pack in______ __with__ _________

does not synthesize hormones and consists of axon terminal neurons

posterioir pituitary gland

hypothalamic neural tissue

the posterior lobe is a downgrowth of

hypothalamus (hypothalamic- hypophyseal tract )

has a neural connection with the

nervous signal from hypothalamus

secretions of the posterior pituitary are controlled by

ADH

synthesized in the cell bodies of hypothalamic neurons(supraoptic nucleus)

posterior pituitary

where is ADH stored

V1 and V2

what are the two types of receptors for ADH

vasoconstriction

v1 receptors mediate

kidneys

v2 receptors located in the principle cells in distal convoluted tubule and collecting duct in the _____

principle cell

ADH binds to V2 receptors on the _______ of the distal convoluted tubules and collecting ducts

reducing urine output w

what is the most important function of ADH to conserve body waste by____

osmotic pressure

baroreceptor

in carotid artery and aortic arch

stretch receptors

in left atrium

ADH high

when the osmotic pressure is high

ADH low

when the osmotic pressure is low

ADH secretion low

when the blood pressure is high

ADH secretion high

when the blood pressure is low

oxytocin

is synthesized in the cell bodies of hypothalamic neurons (paraventricular nucleus)

posterior pituitary gland

where is oxytocin located

stimulates the pregnant uterus to contract

\
may initiate labor

\
cause glandular cell of the breast to release milk to ducts

\
enhande social bonding

function of oxytocin

hypothalamus

where is the actual production of ADH and ocytocin occurs ?

nervous stimulation

the secretion and release of posterior pituitary hormones is controlled by ?

hypothalamus

controls many body functions related to homeostasis ( temperature, appetite, and thirst )

where is thyroid located

t the base of the neck, just below the Adam's apple

vascular

the thyroid is highly_____

metabolic rate

thyroids hormones profoundly **increase** the________ if the body

thyroid hormones

the body’s major metabolic hormones

thyroxine 90%

T4

triiodothyronine 10%

T3

accelerate catabolism

increase the body metabolic rate

calcitonin

CT

calcitonin

decrease the blood calcium concentration by inhibiting breakdown of bone, which would release calcium into the blood

follicular cells and parafollicular cell

the thyroid tisse is made up of two type of cells

follicular cell

most of the thyroid tissue consist of the______

thyroid hormones

most of the thyroid tissue consist of the follicular cell, which secret the iodine-containing________

c cell

parafollicular cell is also called

calcitonin

the parafollicular cells secrete hormone