Endocrine system

gap junction

A junction between two cells consisting of a pore surrounded by a ring of proteins in the plasma membrane of each cell; allows solutes to diffuse from the cytoplasm of one cell to the next; allow communication

neurotransmitter

A chemical released at the distal end of an axon that stimulates an adjacent cell

paracrine

secreted by one cell, diffuse to nearby cell in the same tissue

hormones

distant. when the chemical messenger enter the blood stream and stmulant the organs and cells.

endocrine system

the gland, tissue, and cell that secrete hormones

endocrine gland

A ductless gland that secretes hormones into the bloodstream; for example, the thyroid and adrenal glands.

blood capillaries

vessele where hormones travel throught

liver is exo or endo?

both! it has exocrine that secrets bile into small intestent. but also endocrine gland that secrets hormones into blood.

pancrease and kidney… exo or endo?

both

neuron vs hormones

neuron- only one organ, limited number of cells. short time.

hormones- secreted into blood and circulate the body to different target organs. takes long time.

neuroendocrine cells

act like neurons but also gland cells. secret staff into blood.

target cell and target organs

where hormones get attached to.

pituitary gland

attached to hypothalamus. carry the chemical to the body by secret hormones into the blood vessels.

anterior pituitary gland (adenohypophysis)

no nerve connection to hypothalamus. but it has complex web like blood vessel called hypophyseal portal system.

hypophyseal portal system

complex blood vessel on anterior pituitary. it consist of primary capillaries.

portal venules

small veins of hypophyseal portal system. it run down to the stalk

stalk (infundibulum)

floor of the hypothalamus, where the pituitary gland hang from. depression sphenoid bone

secoundary capillaries

locate in the anterior pituitary.

steps of the hormone secretion of the hypothalamus

hypothalamus controls the anterior pituitary by secreting hormones

hormones travel down to the primary capillaries, and than venules and diffuse out to secondary capillaries.

posterior pituitary (Neurohypophysis)

stalk is part of the posterior pituitary. it is nervous tissue not true gland. hormones are created by neuroendocrine cells.

hypothalamo - hypophyseal tract

bundle of axon in the posterior pituitary gland

TRH (thyrotropin) releasing hormones

hypothalamic releasing, inhabiting hormones that regulate anterior pituitary gland. it promotes TSH (thyroid stimulation hormones) and PRL (prolactin)

Corticotropin-releasing hormone

hypothalamic releasing, inhabiting hormones that regulate anterior pituitary gland. It tells the anterior pituitary to release adrenocorticotropic hormone, or ACTH. ACTH

hormones produced by hypothalamus

the hormone that produced by hypothalamus stimulates the anterior pituitary to secrets and release hormones

oxytocin OT

hypothalamic hormones secrets by posterior pituitary gland. comes from the paraventricular nuclei of the hypothalamus.

antidiuretic hormones ADH

hypothalamic hormones secrets by posterior pituitary gland. supraoptic nuclei, above the optic chiasm.

gonadotropin

NAD, TRO. they target the ovaries and testes (gonads).

Follicle-stimulating hormones (ap)

target- ovaries, testes

FE- Growth of ovaries follicle and secretion of estrogen

M- sperm production

Luteinizing hormones(ap)

target- ovaries, testes

female- ovulation and maintenance of corpus luteum

tyroid-stimulation hormones(ap)

target- tyroid gland

growth of thyroid, secrets thyroid hormones

Adrenocorticotropic hormones(ap)

target- adrenal cortex

growth of adrenal cortex

secretion of glucocorticoids

Prolactin(ap)

target-mammary gland

milk synthesis

growth hormones (ap)

target-liver, bone, cartilage, muscle, fat

tissue growth

antidiuretic hormones (pp)

target-kidney

water retention

oxytocin-pp

target- uterus, mammary gland

labor contraction, milk release

neuroendocrine reflexes

when brain release hormones by responding to some body condition

Insulin-like growth factor (IGF)

GH only has 6 to 20min life span in contract IGF has 20 hours of life span. it boost the GH’s function.

ghrelin

stimulates hunger and GH

involution

shrinking of tissue. ex) pineal gland

suprachiasmatic nuclei (SCN)

synapse with secound-order neuron in SCN

travels down to SCN-paraventricular nuclei-brainstem and spinal code-preganglion synaptic nerve- sympathetic chain ganglia- superior cervical fiber- postganglionic sympathetic fiber- back into pineal gland

this cycle maintain day cycle of darkness and light

melatonin

at the night pineal gland secrets melatonin. it promote sleep and cardiatic breath.

thymus

function- endocrine, lymphoid and immune

locate- superior of the heart, behinde the sternal

involution

dose maturation for white blood cell

secrets thymopoietin, thymosin, and thymulin

thyroid gland

only endocrine

largest adult gland

locates- adjacent to the trachea, below larynx

directly release hormones into blood stream

isthmus

narrow bridge of tissue that joined the thyroid gland

thyroid follicles

sacs that compose the thyroid gland

filled with protein-rich colloid and lined with follicular cells

80um of thyroid hormones (T4,T3) each day

colloid

protein rich substance in the follicle

thyroid hormones

increase metabolic rate. this will result in heat production

increase respiratory rate

increase appetite

accelerate breakdown of food

promote quicker reflexes

parafollicular cells

they respond to rising level of blood calcium and secrets calcitonin.

calcitonin

hormones that stimulates osteoblast activity and antagonizes parathyroid hormones.

parathyroid glands

ovoid gland locate in posterior side of thyroid.

secrets parathyroid hormones(PTH) when the calcium level in the blood is low

not regulated by pituitary gland. it directly monitor blood calcium level.

parathyroid hormones

it stimulates the calcium reabsorption from the bone and reducing calcium loss in urine,

adrenal gland

locates- superior pole of each kidney

has two glands that dose different things like pituitary gland

adrenal medulla and adrenal cortex

adrenal medulla

inner core of adrenla gland. 10 to 20% of the gland.

act as endoctine gland but also ganglion of sympathetic nervous system

has chromaffin cells

chromaffin cells

sympathetic preganglionic nerve fibers penetrate through the cortex to reach chromaffin cells. they are neurons but they don’t have dendrites and directly release staff into blood. so its neuroendocrine cells.

the cell response to stress and fear and secrets neurotransmitters such as epinephrine, norepinephrine, and dopamine. but these chemical work as hormones

these chemical…

increase and prepare for physical activity and alartness

boost glucose level by glycogenolysis and gluconegenesis

epinephrine

epinephrine is also called adrenaline

in brain its neurotransmitter

in adrenal medulla its hormone

has glucose-sparing effect which inhabits insulin

dopamine

it is inhibitory catecholamine neurotransmitter of central nervous system

norepinephrine

in brain its neurotransmitter

in adrenal medulla its hormone

adrenal catecholamines

raise heart rate and blood pressure

inhabuts inessential function of digestion

adrenal cortex

it surrounds the adrenal medulla in adrenal gland.

it produces corticosteroids/ corticoids.

synthesized from cholesterol

5 types (has three categories) that mainly synthesized and other are small amount.

mineralocorticoids

the one of the main steroid categories in adrenal gland

regulate body electrolyte balance

glucocorticoids

the one of the main steroid categories in adrenal gland

regulates metabolism of glucose and other

s3x steroids

the one of the main steroid categories in adrenal gland

developmental and reproduction function

zona glomerulosa

the top layer of adrenal cortex beneath capsule

source of mineralocorticoids

zona fasciculata

middle layer of adrenal cortex

cells are called spongiocytes

secrets glucocorticoids

zona reticularis

the depper layer of the adrenal cortex

secrets glucocorticoids and androgens

aldosterone

most significant mineralocorticoids and it produced only by the zona glomerulosa.

it increase blood pressure by renin-angiotensin-aldosterone system

it stimulates kidney which kidneys to retain sodium.

cortisol

most potent glucocorticoids

secreted by zona fasciculata as response from pituitary gland

it stimulate fat and protein catabolism, glucogenesis, and release fatty acid and glucose into blood.

also anti-inflammatory effect

androgens

primary s3x steroids.

it secreted by zona fasciculata and zona reticularis

pancreas

spongy, retroperitoneal gland

locate: lower stomach and posterier body wall

relate activity with cycle of eating and fasting

has alpha, beta, and delta cells

pancreatic islet

small cluster of endocrine cells in the pancreas that secret insulin

glycemia

blood glucose concentration

alpha cells or glucagon cells

secrets glucagon between meals when blood glucose level is low

glucagon

hormones that exert liver action, glycolysis and glycogenesis

beta cells or insuline cells

it secrets insulin and amylin

insulin

it is secreted during meal or before meal when blood nutrient is rising.

target is liver, skeletal muscle, and adipose tissue.

it stimulates cells to store or metabolize fat, glucose and protein

it also antagonize the glucagon which supress the use of stored fat

amylin

slowing the emptying the stomach and stimulate the sense of satiety

inhabits glucagon secretion

delta or somatostatin cells

secrets soatostatin

somatostatin regulate insulin and glucaagon secretion

PP cell or pancreatic polypeptide

secrets pancreatic polypeptide after a meal

it inhabits the stimulation of pancreas