Chapter 18 Endocrine
Nervous system molecule...
neurotransmitter
Nervous system site of action...
close to site of release
Nervous system traget cells...
muscles (smooth, cardiac, skeletal), gland cells and other neurons
Nervous system time to onset action...
within milliseconds
Nervous system duration of action...
briefer (milliseconds)
Endocrine system molecules...
hormones
Endocrine system site of action...
far from site of release
Endocrine system target cells...
cells throughout the body
Endocrine system time of onset...
seconds to hours or days
Endocrine system duration...
longer (seconds to days)
Endocrine system function
circadian rhythm, growth and development, reproductive system, glanular secretions and contractions of smooth and cardiac muscle fibers, metabolism and energy balance, homeostasis
Target cells
where hormones circulate thru the blood and bind to the receptors
hormones will only affect these cells that possess specific protein
target
respond differently to the same hormone
target cells
exocrine glands
secrete products INTO ducts (not hormones)
sudoriferous, sebaceous, mucous, digestive glands
Exocrine glands
secretes hormones directly into intertistial fluid, do NOT have ducts, hormones diffuse into blood thru caps and carried to target cells
Endocrine glands
pituitary, thyroid, parathyroid, adrenal, and pineal glands
Endocrine glands
regulation of hormone activity
receptors may be down-regulated in high concentration, may be up-regulated in low concentrations of hormone
local hormone; does NOT circulate
paracrine and autocrine hormones
Paracrine hormones
secreted into interstitial fluids and act on nearby cells
Autocrine hormones
those that act on the same cell that secretes them
Synergistic effect
when the effect of two hormones acting together is greater than the sum of their individual effect
Antagonistic effects
if one hormone opposes the action of another hormone
Permissive effect
the action of some hormones on target cells require a simultaneous or recent exposure to a second hormone
Neural Stimuli
postive feedback; nerve fibers stimulate hormone release
Humoral Stimuli
postive feedback; secretion of hormones in direct response to changing blood levels of ions and nutrients
cannot diffuse through lipid-bilayer
water soluble hormones
attaches to the outer surface and acts as the first messenger
wter soluble hormones
First messenger of water soluble hormones
cause production of a second messenger where hormone stimulated responses take place
binds to receptors-activates G protein-adenylylcyclase activate-ATP converted to cAMP-protein kinases (adds phosphate) activated-activated protein either activates or inactivates them
water soluble hormones mechanism
phosphorylated proteins (water soluble)
causes reaction
phosphodiesterase proteins
shuts off cAMP (water soluble hormones)
Second messneger hormone in water soluble hormones
cyclic adenosine monophoshate (cAMP)
Hormonal stimuli
releases hormones in response to hormones produced by other endocrine organs
hypothalamus and pituitary gland work together to control..
other endocrince glands
major link between the nervous and endocrine system
hypothalamus
a stalk that connects the hypothalamus and pituitary gland
infundibulum
lipid soluble hormones
steriods, thryoid hormione, nitric oxide
circulates blood to transport proteins and binds to receptors in nucleus or cytoplasm of cell; turns specific genes on or off; synthesis of a new protein that alters cell activity to caise the response of hormone
lipid soluble hormones
secretion of hormones in direct response to changing blood levels of ions and nutrients
neural stimuli
regulates the release of some of the anterior pituitary hormone by secreting five releasing hormones and two inhibiting hormones
hypothalamus
Testes
produces testerone, sperm, and inhibin
Ovaries
produces estradiol and estrone, progesterone, relaxin, inhibin
resistance reaction
second stage in the stress response; last longer than the figh or flight response; can lead to exhaustion
Pineal gland
secretes melatonin; helps regulate the body's biological clock
Thymus
produces thymosin, THF, TF, thymopoitien
promotes maturation of the immune system's T cells
Thymus
first stage of the stress response; stimulates the body's resources to prepare for immediate activity
fight or flight response
distress
harmful stress that may be damaging
Eustress
everyday stress that prepares us to meet challenges
Aldosterone (zona glomerulosa)
helps regulate sodium and potassium homeostasis
RAA control secretions of...
aldosterone; factors being rising of K+, low Na+, decreasing BP
regulated by negative feedback
glucocorticoids (zona fasciculata)
helps control protein brkdwn, glucose formation, lipolysis, resistance to stress, inflammation, immune response
glucocorticoids (zona fasciculata)
Zona Reticularis
adrogens; masculinizing effects
zona fasciculata
glucocorticoids; affects glucose homeostasis
regulates mineral homestasis; mineralocorticoids
Zona glomerulosa
elevated osmotic BP. dehydration, blood loss, pain. stress...
determines the amount of ADH that is secreted
Diabetes Inspidus
insuffient release of ADH from posterior pituitary
oxytocin
stimulates contraction of smooth muscle of uterus during childbirth; stimulate mammary glands to cause milk ejection
ADH hormone
the amount secreted depends of the blood osmostic pressure
ADH
conserves body water by decreasing urine volume, decrease water loss thru prespiration, raises BP by constricting arterioles
formed by the axons from the neurosecretory cells of the hypothalamus
hypothalmic hypophyseal tract
Anterior pituitary hormones regulated by negative feed back
thyrotrophs, gonadotrophs, corticotrophs
how the releasing and inhbiting hormones reach the anterior pituitary from the hypothalamus
hypophyseal portal system
blood flows from one capillary network into a portal vein
hypophyseal portal system
Growth Hormone (Anterior Pituitary)
secreted by somatotrophs; releasing hormone; somatostatin, inhibiting hormone; somatostatin
Thyroid-stimulating hormone (TSH) (Anterior Pituitary)
aka thyrotropin
TSH (Anterior Pituitary)
secreted by; thyrotrophs, releasing hormone; thyrotropin, inhbiting hormone; growth hormone inhibiting hormone (GHIH)
Follicle-stimulating hormone (FSH) (Anterior Pituitary)
secreted by; gonadotrophs. releasing hormone; gonadotropin releasing hormone (GnRH), no inhibiting hormone
Luteinizing Hormone (LH) (Anterior Pituitary)
secreted by gonadotrophs; releasing hormone gonadotropin-releasing hormone (GnRH)
Prolactin (PRL) (Anterior Pituitary)
secreted by lactotrophs, releasing hormone prolactin-releasing hormone (PRH), inhibiting hormone prolactin-inhibiting hormone (dopamine)
Adrenocorticoids hormone (ACTH) aka corticotropin
secreted by corticotrophs; releasing hormone prolactin-releasing hormone (PRH), inhibiting hormone-prolactin-inhibiting hormone (dopamine)
Pancreatic Islets cells
alpha-glucagon, beta-insulin, delta-somatostatin, F-pancreatic polypeptide
Acini (pancreas)
exocrine cells of the pancreas that are arranged in clusters
produces digestive enzymes that are delivered to the GI tract thru ducts
Acini (pancreas)
increase BMR, help maintaine body temp, stimulate protein synthesis, accelerate the use of glucose and fatty acids for ATP production, upregulate beta receptors, accelerate body growth
Thyroid gland
calcitonin
made by the parafollicular ( C-cells) of the thyroid gland and when secreted lowers the blood calcium and phosphate levels
chief cells (principal cells) (parathyroid)
produces the parathyriod hormone (PTH)
Oxyphill cells (parathyroid)
function is unknown however with parathyroid cancer it secretes excess PTH
Areas of the parathyroid funct
bone, kidneys, GI (calcitrol)
hormone producing cells that secretes hormones epinephrine and noradrenaline; involved in the fight or flight response
chromaffin cells (adrenal glands)
adrenal medulla
inner region of adrenal glands
modified sympathetic ganglion which is stimulated by preganglionic neurons of ANS
chromaffin cells (adrenal glands)
lies between follicles adn produce the hormone calcitonin
parafollicular cells (c-cellls) (thyroid gland)
makes up the wall of each thryoid follicle
follicular cells (thyroid gland)
stimulated by TSH to produce thyroxine (T4, T3)
follicular cells (thyroid gland)
secreted by corticotrophs; releasing hormone corticotropin -releasing hormone (CRH); inhibiting hormone Dopamine
melanocyte-stimulating hormone (MSH) (Anterior pituitary)
glucagon (pancreatic islet)
control of secretions: decrease blood level of glucose; exercise
action; increase in BS by accelerating brkdwn of glycogen into glucose in liver; converting other nutrients into glucose in liver and releasing glucose into blood
glucagon (pancreatin islet)
classified as catecholamines
epinephrine and norepinephrine
epinephrine and norepinephrine secretion
in time of stress and exercise, impulses from hypothalamus stimulates sympathetic preganglionic neurons which in turn stimulate chromaffin cells to secrete epinephrine and norepinephrine
parathyroind hormone
major regulator of calcium, magesium, and phosphate ions level in the blood
stimulates corpus uteum in ovaries to continue production of estrogens and progesterone to maintain pregnancy
Human chorionic gonadotropin (hCG)
Hirsutism
abnormal condition of excess androgen secretion; primarly in woman; excessive body and facial hair in a male pattern
Cushing's syndrome
high levels of cortisol; hyperglycemia, poor wound healing, osteoporosis, dermatitis, fat redistribution (spindly arms and legs, moon face, buffalo hump, trunical obesity
Grave's disease
most commnone cause of hyperthryoidism resulting in enlarged thryoid; exothalmos-eyes bulging, irritability, muscle weakness, sleeping problems, tachycardic, poor tolerance of heat, diarrhea, weight loss
Goiter
enlargement of thyroid gland; maybe associated w/ hyperthyroidism, hypothydroidism, or euthydriodism; found in third world countries due to inadequate of iodine resulting in low level of thyroid hormone in blood that stimulates secretion of TSH
Gigantism
over production of growth hormone in CHILDHOOD causing excessive growth