Ch. 4 + 18 Intercellular Communication & General Principles of Hormonal Communication Flashcards
Intracellular control
- communication within cells of the body
Example of intracellular communication
- synthesis of neurotransmitters need communication between rough ER, smooth ER, ribosomes, ect.
Intercellular / Extracellular Control
- communication between the cells of the body
Example of intercellular communication
release of ACTH during stress causes the release of cortisol
intercellular communication is also known as
extracellular communication
types of intercellular communication
- direct
- indirect
direct intercellular communication
- Gap junctions
Indirect Intercellular (between -extra -) chemical messangers
- paracrine
- neurotransmitter secretion
- hormonal secretion
- neurohormone secretion
Example of intercellular communication through gap junctions
- phagocytes recognize and destroy bacteria and invaders (phagocytosis)
- antibodies “marked” bacteria as foreigners to destroy them (Antigen-antibody interaction)
Intercellular communication through gap junctions does not involve
ECF
Intercellular communication through Gap junction is achieved through
signalling molecules on the surface of the cells
- posses identifying markers on cell membranes
Intercellular communication through Gap junctions is an ________ way of communication
intimate
Process of indirect intercellular communication
stimuli –> specific cells of the body –> sp. chemicals –> ECF –> Sp. chemical possess ligand –> bind/ interact with receptors on the target cell –> responce
Paracrine signals
- local chemical messenger exerts their effects on the nighboring cells in an immediate environment
Paracrine signals are spread through
diffusion and act at a short distance
Paracrine signals acts
at a short distance
do Paracrine signals enter the blood
no
Example of paracrine signal
Histamine
- causes vasodilation of the neighbouring blood vessels
Neurotransmitters
short range chemical messangers
- diffuse across narrow space to act locally on adjoining target cells
process of neurotransmitters
electrical signal –> nerve cell –> neurotransmitter –> ECF –> affects adjoining target cells (muscle, gland or neuron)
neurotransmitters are _____ range chemical messangers
short range
what are the short range chemical messangers
- paracrine signals
- neurotransmitters
hormones are _____ range chemical messangers
long
Hormones are secreted into the blood by
endocrine glands in response to an appropriate signal
Examples of hormones
GH only binds to muscles and bones in the body
Hormones effect
a specific target cell
Hormone secretion process
signal / stimuli –> endocrine gland –> hormone –> blood –> target gland –> receptors –> response
Neurohormones are released into the blood by
neurosecretory neurons
Examples of neurohormones
- ADH
- oxytocin
signal transduction
Process of chemical messangers action on target cells
endocrine cells –> first (extracellular) chemical messanger –> blood –> target cells –> receptors–> responds by:
1. closing / opening specific channels in the membrane
2. Second messangers (turn on biochemical events in cells
examples of second messangers
- cAMP
- Ca 2+ - PIP2
- cGMP
First messangers
- extracellular chemical messanger binds to receptor
- open of close the specific channels to regulate the movement of a particular ion in and out of the cell
OR - transfer extracellular messenger to the second messenger
G protein is known as
a middle man
Example of cyclic AMP second messenger system
synthesis of estrogen in the ovary by Luteinizing hormone
Functions of cAMP
- modification of heart rate
- formation of female sex hormone in the ovaries
- breakdown of stored glucose in the liver
- reception of a sweet taste by a taste bud
- conservation of water during urine formation
cGMP serves a a second messanger in a system _________ to the cAMP system
analogous
Example of cGMP
- the signal transduction pathway involved in vision
aldostrone
- regulates metabolism, h2o, and electrolyte balance by acting on the kidneys
cortisol
helps the body cope in stressful situations
GH
promotes growth and development
FSH and LH
controls reproduction
erythropoiethin
regulates blood cell production
Gastrin, CCK
digestion and absorption of food in GI
peptides and protein hormones are made up of
amino acids
Hormones secreted by which 10 glands are peptide
- hypothalmus
- ant. and post. pituitary
- pancrease
- parathyroid
- GI
- kidneys
- liver
- thryroid
- heart
- thymus
ACTH stimulates
the adrenal glands
MSH stimulates
melanocytes
Once stimulated by ACTH the adrenal glands release
cortisol
what are melanocytes responsible for
skin color
b-Endorphin
- analgesic
- pain releif
Pre-promelanocortin hormones
- ACTH
- MSH
-B-Endorphin
Steriod hormones includes hormones secreted by the
- adrenal cortex
- gonads
- placenta
Steriod hormones are derivatives of
cholesterol
are steriod hormones stored in the cell
no they are released immediatly into the blood
Steriod hormones undergo _________ in the blood or in other organs
interconversion
example of interconversion
progesterone becomes cortisol and aldosterone
exampels of hormones deprived from cholesterol
- progesterone
- dehydroepiandrosterone
dehydroepiandrosterone id a precursor for
- testosterone
- estradiol
Amines / catecholamines are deprived from
the amino acid tyrosine
Amines / Catecholamines include hormones secreted by
the thyroid and adrenal medulla
Are enzyme sythesizing Amines / Catecholamines located
in cell organelles
peptides solubility
hydrophilic
Catecholamines solubility
hydrophilic
thyroid hormones solubility
lipophilic
steroid hormones solubility
lipophilic
peptide hormones structure
chains of specific amino acids
Catecholamines structure
tryosine derivative
thyroid hormone structure
iodinated tryosine derivative
steriod hormone structure
cholesterole derivaitive
peptides synthesis
- in rough ER; packaged in the golgi complex
catecholamines synthesis
in cytosol
thyroid hormone synthesis
in colloid, and inland extracellular site
steriods synthesis
stepwise modification of cholesterol molecule in various intracellular compartments
peptide storage
large amounts in secretory granules
catecholaminesstorage
in chromaffin granules
thyroid hormones storage
in colloid
steriod hormones storage
not stored; cholesterol precursor stored in lipid droplets
peptides secretion
exocytosis of granules
catecholamines secretion
exocytosis of granules
thyroid hormone secretion
endocytosis of colloid
steroid hormone secretion
simple diffusion
how are peptides transported in the blood
as a free hormone
how are catecholamines transported in the blood
half bound to plasma proteins
how are thyroid hormones transported in the blood
mostly bound to plasma proteins
how are steriods transported in the blood
mostly bound to plasma proteins
peptides receptor sites are located
surface of the target cell
catecholamine receptor sites are located
surface of the target cell
thyroid hormone receptor site is located
inside the target cell
steriod receptor site is located
inside target cell
peptides mechanisms of action
- channel changes or activation of second messanger system to alter the acitivy of target proteins that produce the effect
catecholamine mechanisms of action
activation of second messanger system to alter activity of target proteins that produce the effect
thryroid hormone mechanisms of action
activation of a specific genes to make new proteins that produce the effect
steriod mechanisms of action
activation of specific genes to make new proteins to produce the effects
peptides hormones of this type
majority of hormones
catecholamine hormones of this type
only hormones from the adrenal medulla
thyroid hormone of this type
only hormones from the thyroid follicular cells
steriod hormones of this type
hormones from the adrenal cortex and gonads
What are the three ways hormes can influence the activity of another hormone at a given target cell
- permissiveness
- synergism
- antagonism
permissivness
- one hormone must be present in adequate amounts
- one hormone enhances the reponsiveness of another hormone at the target gland
example of permissiveness
thyroid hormone increases receptors for epinephrines target cells (cardiac muscle cells)
Synergism
- actions of more than one hormone are COMPLEMENTARY
- combined effect is greater than the sum of theri seperate effects
synergism example
- FSH and testosterone on testes are required to maintain sperm production
Antagonsim
- one hormone causes th eloss of another hormones receptors, reducing the effectiveness of the second hormone
Antagonism example
progesterone inhibits the action of estrogen (reducing the receptors) on uterine muscles to prevent miscarriage during pregnancy
plasma concentration of active hormone depends on
- hormones rate of secretion into the blood by endocrine glands
- extent it binds to plasma proteins
- rate of removal from the blood by inactivation or excretion
- avaliability and sensativity of target cell’s receptors for the hormone
inputs that control homrone secretion
- plasma concentration of active hormone
- bu other hormones (negative feedback)
- neuronal control (ANS)
Dinural Rhythm
- time of day effects the amount of hormone synthesized
What are the hormones secreted by the anterior pituitary
- ACTH
- TSH
- GH
- PRL
- LH & FSH
what are the hormones secreted by the posterior pituitary
- Vasporessin / ADH
- Oxytocin
the hypothalmus is known as the
neural control center
where are ADH and oxytocin made
hypothalmus
the anterior pituitary gland
directly synthesiszes hormone
the posterior pituitary gland
store hormones
what are is the target cells of hormones secreted by the hyopthalmus
anterior pituitary
what are the functions of the hormones released by the hypothalamus
controls the release of anterior pituitary hormones
what is the target cells of vasopressin
- kidney tubules
- arterioles
function of vasopressin
increases h2o reabsorption (kindneys)
produces vasoconstriction (arterioles)
what are the target cells of oxytocin
- uterus
- mammary glands
what are the function of oxytocin
- increases contractility (uterus)
- causes mild ejection (mammary glands)
TSH target cell
thryroid follicular cells
function of TSH
stimulates T3 and T4 secretion
ACTH target cell
adernal cortex
ACTH function
- stimulates cortisol secretion
GH target tissue
- bone; soft tissues
- liver
GH function
- stimulates growth of bones and soft tissues
- metabolic effects (protein anabolism, fat mobilization, and glucose conservation)
- stimulates somatomedin secretion
FSH target cell in females
ovarian follicles
FSH target cell in males
seminiferous tubules in testes
FSH function in females
promotes follicular growth and development
- stimulates estrogen secretion
FSH function in males
stimulates sperm production
LH target cell in females
ovarian follicles and corpus luteum
target cells in males
intersticial cells in testes
LH function in females
stimulates ovulation, corpus luteum development, and estrogen and progesterone secretion
LH function in males
stimulates testosterone secretion
Prolactin target cell
mammary glands
prolactin function
- promotes breast development
- stimulates milk secretion
melatonin target cell
brain; anterior pituitary; reproductive organs; immune system
melatonin functions
bodys biological rhythm
- inhibits gonadotropins
where is melatonin secreted by
pineal gland
what does the thyroid gland secrete
T4 and T3
T3 and T4 target cell
most cells
T3 and T4 function
increases the metabolic rate
- essential for normal growth and development
Thyroid cell C cells secrete
calcitonin
calcintoin target cell
bone
function of calcitonin
decreases plasma CA2+ concentration
Adrenal cortex (zona glomerulosa) secretes
aldosterone
aldosterone target cell
kidney tubules
aldosterone function
increases NA+ reabsorption and K+ secretion
Adrenal cortex (zona faciculata and zona reticularis) secretes
cortisol
androgens
cortisol target cell
most cells
cortisol function
increases blood glucose at the expense of protein and fat stores; contributes to stress adaption
androgens target cells in females
bone and brain
androgen function in females
- prubertal growth spurt and sex drive in females
the adrenal medualla secretes
epinephrine and noreepinephrine
epinephrine and norepinerprine target cells
sympathetic receptor sites throughout the body
epineprine and norepinerine function
- reinforces sympathic nervous system
- contributes to stress adaptation and blood rpessure regulation
what hormones does the pancrease (ilslets of langerhans) secrete
- Insulin (b cells)
- Glucagon (a cells)
- somatostatin (D cells)
insulin target cells
most cells
glucagon target cells
most cells
insulin function
- promotes cellular uptake, use and storage of absorbed nutrients
- stores glucose as glycogen in the liver
glucagon fuction
- important in maintaining nutrient levels in blood during postabsorption state
Somatostatin target cell
digestive cells
pancretic islet cells
somatostatin
- inhibits digestion and absorption of nutrients
- inhibits secretion of all pancretic hormones
PTH target cell
bone, kidneys, intestine
PTH function
increases CA2+ concentration
estrogen function
- promotes follicular development; governs development of secondary sexual characteristics; stimulates uterine and breast growth
- promotes closure of epiphyseal plate
estrogen target cells
- female sex organs
- bone
progesterone target cell
uterus
progesterone function
prepares for pregnacy
testosterone target cell
male sex organ
bone
testosterone function
- stimulates sperm production; governs developmetn of secondary sex characteristics; promotes sex drive
- enhances pubertal spurt; promotes closure of epiphyseal plate
inhin target cell
anterior pituitary
inhibin is secreted by
ovaries and testes
inhibin fuction
inhibits secretion of follicle stimulating hormone
renin stimulates
aldosterone secretion
renin target cell
adrenal cortex
what hormones does the kidneys secrete
renin
erythropoietin
erythropoietin target cell
bone marrow
erythropoietin function
stimulate RBC production
thymosin is secreted by
thymus
thymosin target cell
t lymphocytes
thymosin function
enhances T lymphocyte proliferation and function
how to identify is a hormone is relased from the hypothalmus
releasing hormone
how to identify is a hormone is relased by the anterior pituitary gland
stimulating hormone
synthesis of peptide hormones
preprohormone systhesized by golgi, RER, SER released into the blood –>then becomes prohormone (activated hormone) when secreted into the blood
how many hypophysiotropic hormones are there
7
hypophysiotropic hormones
- control if the secretion of each pituitary hormone is stimulated or inhibited
TRH
sitmulates the release of TSH and prolactin
CRH
stimulates the release of ACTH
GnRH
stimulates the release of FSH and LH
GHRH
stimulates release of growth hormone
GHIH
inhibits release of growth hormone and TSH
PRH
stimulates the release of prolactin
PIH
inhibits release of prolactin
