CHAPTER 41 Flashcards
define Hormones
chemical signals that is secreted from the endocrine cells.
define endocrine cells
cells that secrete the chemical signals.
define Target cells
receptors for the chemical signals
where does the circulating cells diffuse into?
the circulating cells diffuse into the blood where they can activate the target cells far from the site of release.
compare and contrast paracrine and autocrine.
Paracrine= signal affects the target cells that are near the site of release.
autocrine: signal affects the cells that released the signals.
how do some of the endocrine cells exit ?
some of the endocrine cells can exit as single cells such as in the digestive tract.
compare and contrast endocrine and exocrine glands.
endocrine glands: secretory organs composed of endocrine cells which secrete signals into the extracellular fluid.
endocrine glands: have ducts that carry their signals to the outside of the body or a body cavity.
how do neurons communicate with one another?
through neurotransmitter
what are the neurotransmitters called that diffused to the blood?
neurohormones
what are pheromones?
chemical signals that are secreted in the environment.
what action is taken by our body in response to the chemical signals>
signals are widespread in the sense that they can diffuse throughout the body, so in response the tissues in our body evolves sensitivity to the hormones to coordinate their activities with the secreting organ.
give an example of how the body reacts to the signals.
an example of the signals being widespread and the tissues evolving is = testosterone. testosterone is released when the sperms are made by testes but it is also active on tissues such as the brain, vas deferens, penis, liver and muscles . each of these tissues as a result has evolved ability to respond to the single signal.
another example
epinephrine
what is the other name for epinephrine?
epinephrine is also called adrenaline whic his released by the adrenal glands.
what is the function of epinephrine>
fight and flight response
released by fear provoking stimulus.
what are the four main things that results from epinephrine release
1) speeds heart rate and the strength of contractions.
2) constricts the blood vessels to the gut , muscles get blood supply.
3) stimulates breakdown of glycogen for quick enrgy
4) stimulates breakdown of fat as a source of energy.
how many responses can result from one hormone?
one hormone can trigger responses in different types of cells.
what is an example of a hormone acting on different types of cells?
ex: epinephrine
fight or lfight response which acts on different parts of the body such as the brian, liver, penis , vas deferens.
what does epinephrine bind to?
epinephrine binds to the receptors in theh eart, blood vessels , liver and fat cells.
what determines where the hormones acts>
where hormones act depends on the receptors.
what determines the action of it( function) ?
what is does depends on the type of cell that it binds to in terms of the downstream cascade initiated by receptor in that cell type.
what else can the chemical signals be used for>
chemical signals were pivotal for communication between orgnanisms.
what is the function of prolactin in mammals>
in female mammals , prolactin is responsible for mammary tissue stimulation for the production of milk
function of prolactin in pigeons and doves
causes production of “crop milk” . when the birds are feeding their new borns the sloghed off lining of crop is regurgitated to feed young.
prolactin in amphibians
- prepare for reproduction by seeking for water sites.
prolactin in fish
regualtion of osmotic balance when the salmon moves from salt water to fresh water.
True or false: the structure of prolactin is the same in all vertebrates
TRUE
What are the three chemical groups that contains hormones
1) steroid hormones
2) amine hormones.
3) peptides or proteins
characteristics of a peptide or protein
- water soluble
- transported in blood with receptors on cell surfaces
characteristics of a steroid hormone
- lipid soluble
- synthesized by cholesterol
- must be bound to carrier proteins to be carried to the blood.
amines characteristics
- derivatives of tyrosine
what is the characteristics of a hormone receptor in terms of its location?
hormone receptors can be intracellular or membrane bound.
receptors that are inside are called?
lipid soluble
receptors that are on the outside
water soluble hormones that cannot pass through the cell membrane.
what are the three membrane bound receptors
they are glycoproteins with three domains:
1) binding domain : projects outside of the plasma membrane
2) transmembrane domain : anchors the receptors
3) cytoplasmic domain: extends into the cytoplasm and initiates the target cell response.
what hormone is found in the adipose tissue?
leptin
heart : hormone
atrial natriuretic peptide
kidney
eythropoietin
stomach
gastrin
intestine
secretin, cholecystokinin
skin
vitamin D, ( cholescalciferol)
liver
somatomedins, insulin like growth factors
what is the pituitary gland attached to ?
hypothalamus of the brain
what does the pituitary gland connect to
connects the nervous an endocrine systems.
what are the two types of pituitary glands?
anterior
posterior
what hormones are found on the posterior pituitary
oxytocin and ADH (antidiuretic hormone) =vasopressin
what is the function of the two hromones found i nthe pituitary gland?
the two hormones are ADH and oxytocin
oxytocin = stimulates contractions , milk flow, promotes bonding .
ADH= serves to retain the water by the kidneys when necessary.
function of oxytocin
1) secreted during child birth , increases contractions of the uterus
2) babys suckling stimulates release of oxytocin, causes milk “ let down” , flow of milk from the breast
3) nasal spray in adults showed that they were more trusting .
function of vasopressin
- secreted when blood pressure falls and the blood is too salty.
1) water retention in kidneys
2) by constricting the blood vessels it increases the blood pressure.
what inhibits and increases the production of ADH?
alcohol consumption inhibits
blood loss increases ADH
Does the hypothalamus communicate the same way with anterior and posterior pituitary?
NO, the hypothalamus communicates differently.
how does the hypothalamus send secretions to the anterior pituitary?
portal blood vessels
what are the five main hypothalamic hormones?
1) Prolactin releasing and release inhibiting hormones.
2) Thyrotropin releasing hormones
3) Corticotropin releasing hormones
4) Gonadtotropin releasing hormones
5) Growth hormone- releasing hormone.
what are the four tropic hormones secreted by the anterior pituitiary
1) thyrotropin
2) corticotropin
3) follicle-stimulating hormone
4) luteinizing hormone.
LH and FSH are part of what
LH and FSH are part of the gonadotropins
1) LH: luteinizing hormone causes ovulation
2) FSH: Follicle stimulating hormone causes growth of ovarian follicle , stimulates sex steroid secretion.
ACTH
adreno cortico tropic hormone
- causes growth of adrenal cortex , induces secretion of cortical glucocoticoids.
Thyrotropin
causes secretion of thyroxine from thyroid gland.
three organ relationship
organ#1 hypothalamus
organ #2 anterior pituitary
organ # 3 ovary
what does the hypothalamus , anterior pituitary and the ovary secrete?
GnRH is secreted by the hypothalamus
GnRH acts on anterior pituitary to cause secretion of gonadorophns , LHand FSH
- gonadotrophins act on ovary to cause secretion of estradiol
what does estradiol do ?
estradiol acts on hypothalamus to inhibit secretion of GnRH.
what cell secretes testosterone?
leydig cells
what kind of hormone is testosterone
steroid hormone
what is the developmental effects of testosterone?
developmental effect= causes growth and differentiation of masculine structures (peni, scrotum, sperm ducts, deep voice, masculine brain)
adult effects of testosterone
sex drive, aggressiveness , production of sperm, hair growth , muscle mass
ovaries
site of production and maturation of egg cells.
name the major hormones
estrogens and progestins
ex, estradiol and progesterone.
what kind of hormones are progesterone and estradiol
steroid hormones.
function of estrogen
enlargement of breasts , cellular changes of vagina and uterus, increase in subcutaneous fat, involved in control of ovulation.
function of progesterone
prepares uterus for implantation of embryo , behavioral effects etc
what happens when athletes take body building androgenic steroids?
hypothalamus makes low levels of GnRH which acts on the anterior pituitary ( low level of gonadotrophins are secreted ) , testes might shrink and theres an escess amount of testosterone which acts on the hypothalamus to inhibit produciton of GnRH.
What happens when one ovary is removed?
since half the estroge nis goen, it reduces the inhibition on the hypothalamus so GnRH goes up , FSH and LH goes up , size of ovary increases .
medulla
central portion secretes epinephrine (adrenalin) and norepinephrine (noradrenalin)
what does epinephrine do/
it is an amine, hydrphilic, acts on cell surface receptor
- increases the heart rate , blood pressure , diverts blood to muscles.
what are the two kinds of receptors on epinephrine?
alpha and beta adrenergic
what does the cortex secrete?
corticosteroids: glucocorticoids, mineralocorticoids, sex steroids.
function of glucocorticoids and mineralcoricoids?
glucocorticoids: glucose metabolism
mineralocorticoids: mineral balance.
what does stress do?
increases the amount of cortisol.
function of cortisol
stimulates other cells to decrease use of glucose and metabolize fats and proteins, release glucose, inhibit inflammation.
long term disadvantages of cortisol
kills brain cells, loss of immune function , wasting of muscles elevated blood pressure , elevated fat metabolism
what does the thyrotropin secrete
causes secretion of thyroxine from thyroid gland.
what does follcied formed by epithelial cells produce
thyroxine
thyroxine
begins as a glycoprotein, thryoglobulin and becomes T3 and T4 with the additon of iodine.
main function of the thyroxine
- increases the metabolic rate
- promotes uses of carbohydrates in preference to fats .
- cold stress increases thyroxine secretion
- important during growth development , increases amino acids uptake and synthesizes protein.
insufficient thyroxine leads toserious physical deficiencies n physical and mental growth
cretinism.
how is the level of TRH determined
brain uses body temperature and daylength
goiter is caused by
thyroid dysfunction
goiter is
enlarged thyroid gland
hyperthyroidism
(thyroxine excess
caused by autoimmune disease ( attacks the own tissues)
antibody activates
TSH receptors on follicle cells and increases thyroxine
thyroid remains stimulated and grows bigger.
hypothyroidism
- (thyroxine deficiency) is the result of low circulating thyroxine.
how is hypothyroidism caused>
common is iodine defiency -folicle ells cant produce thyroxine.
thyroglobulin is produced but not converted effeicently converted to T3 and T4 and thymus enlarged.
what causes the growth of bone
somatomedins.
stimulates production and secretion of milk , gowth of mammary tissues
prolactin
melanocyte
stimulating hormone , unknwon function in humans
endogenous opiates in brain but pituitary secretion unknwon
endorphins and enkephalins
lack of insulin leads to
hyperglaycemia
pancreas is located in
below the stomach that produces insulin
lack of insulin
type I or juvenile onset diabetes
lack of insulin responsiveness causes
TYPE II or adult onset diabetes
copious production of sweet urine
diabetes mellitus
insulin replacement therapy allows those with type I diabetes to
live normally :
what makes the cell more permeable to glucose
when insulin binds to its receptor on the cell membrane.
a high glucose concentration in the blood
increases urine output which means you have to pee a lot
what is the result of water moving into the blood osmotically
blood volume increases and thus the production of urine increases
high glucose in kidneys
pulls more water into the urine.
what is the islet of langerhans
clusters of endocrine cells in the pancreas that produce three different hormones.
what are the three different hormones that is produced by the islets of langerhadns
1) beta cells - produces insulin
2) alpha cells- produces glucagon
3) delta cells - produces somatostatin
what is glucagon
stimulates liver to convert glycogen back to glucose
somatostatin
inhibits release of both insulin and glucagon
