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60 Cards in this Set

  • Front
  • Back
Characteristics of receptors
-memory proteins
-if cell does not have receptor, cell is blind to it
-different cells have different receptors for same chemical
-receptor determines response, not signal
-ligand/1st messengers/signal= means same
Classes of Receptors
-gated channels
-receptor enzyme
-G-protein linked receptors
-intracellular receptors
Gated channels:
-closed unless gets right signal
-they open when they get signal
-allow ions to move across cell membrane--ions will change membrane potential
-can be attached to extracellular matrix and also inside cell
-will restructure or reorganize cell shape structure
-turn enzyme on or off--connected to enzyme
-cell recognition, immune system
Receptor enzyme:
-outside is receptor
-on other side of membrane is enzyme, so will start chemical reaction
-called protein kinase--causes phosphorylation (adding phosphate)
G-protein linked receptors:
-binds to receptor
-receptor activates G-protein
-then G-protein does something else
-can turn on or off enzymes
-can open gated ion channels
Intracellular receptors:
-all the way inside cell--in cytoplasm or nucleus
-when activated, they turn on specific genes in DNA
-new mRNA made
molecule that mimicks the real signal or messengers
molecule that binds to receptor and prevents real signal from binding and having effect
Down regulation:
-decrease in # of receptors or decrease in ability of signal to receptor
-can happen if too much signal or agonist around or around for too long
Up regulation:
-increase in # of receptors over time
-can occur if you have less signal present
-totally separate signal that tells cell to make receptors for that signal
-water-liking, aka lipophobic
-rely on having membrane receptors
-water-hating, aka lipophilic
-could diffuse right through, can get inside using intracellular receptors
Signal transduction:
relaying binding of signal to receptor to response a change inside the cell
when one signal can make change
2nd messenger-->cascades
membrane transducers
have protein in membrane that will relay signal
types of membrane transducers
receptor enzymes
G-protein linked receptor
Intracellular receptor
Chemical messengers
amino acids
peptides and proteins
Amino acids
primarily in nervous system
-derived from amino acids, tyrosine will turn into Epi, tryptophan will turn into dopamine and histidine will turn into histamine
-are H2O soluble--will use membrane receptors
Peptides and proteins
-too big to get through membrane
-water soluble
-will only use membrane receptors
-derived from cholesterol
-occus in mitochondria and smooth ER
-lipid soluble
-will use intracellular receptors--can get inside
-can be made by almost any cell type in body if they get correct signal
-most of the time act as paracrine
-made from fatty acid--lipid soluble
-use intracellular receptors
Steps for intracellular receptors:
1. Hormone will diffuse across membrane and into cell
2. Can be chemically modified
3. Will bind to receptor in cytoplasm or nucleus
4. Hormone will bind to receptor inside nucleus
5. Hormone receptor complex will bind to specific place on DNA
6. Will trigger formation of new mRNA (transcription)
7. mRNA go out into cytoplasm where translation occurs
8. Can change cell metabolism, structure, function
9. Amplification needed during transcription
Process for membrane receptors
1. Signal binds to receptor
2. Hormone receptor complex activates G-protein
3. G-protein activates enzyme, adenylate cyclate
4. Takes ATP and hooks into circular molecule making cAMP
5. cAMP goes into cell and causes change
6. cAMP activate enzyme protein kinases
7. Protein and ATP-->protein+ADP, phosphorylate protein
8. change occurs in cell
enzyme that breaks down cAMP
Endocrine system characteristics:
-control system in body
-hormones are released and go into blood and everywher in body
-all cells exposed
-only cells that respond are ones with correct receptor
-frequently released in response to need in body
-different cell types respond differently to same hormones because receptors are different
-cause substantial biochemical changes inside cell
-effects of hormones last different time
What determines how long hormone lasts?
1. Time pattern of hormone release:
-some constant
-regularly released
-only released on demand
2. How long does it last in blood
-amines, peptides and proteins tend to last shorter time
-steroids last longer
3. How long does effect last after hormone is gone
Direct effect (hormone action)
hormone goes to target cell and causes change
Permissive effect (hormone action)
action of one hormone allows a second, different hormone to have effect
Synergistic effect (hormone action)
action of two or more hormones on target produce beast response
Antagonistic effect (hormone action)
action of two hormones on single target are opposite each other
Trophic (tropic) effect) (hormone action)
one hormone causes release of another hormone
pituitary gland
-divided into two parts: anterior and posterior
-during development, came from different tissues
posterior pituitary gland
-embryonically from brain nerve cells located in hypothalamus
-sometimes called "neurohyphysis"
-hormones released are made by neurons called neurohormones
anterior pituitary gland
-no direct neural connections to hypothalamus
-only connection is by way of circulatory system
-hypothalamus still controls it, in different way
-hormones can have different effects
-stimulating hormones--will cause anterior pituitary to release hormones
-inhibiting hormones--turn off release of hormone, will cause anterior pituitary to stop
Functions of endocrine system:
-help control internal environment
-respond to large changes in internal environment
-helps coordinate growth and development
-contributes to basic processes of reproduction
-helps regulate organic metabolism and energy balance (ATP)
Pituitary gland functions:
1. Control thyroid gland
2. Regulates growth
3. Regulates reproduction
4. Regulates skin pigmentation
Thyroid gland functions:
1. Regulates organic metabolism and energy balance
2. Regulates growth and development
3. Regulates activity of nervous system
Parathyroid gland functions:
Regulates concentration of ions in blood, specifically Ca+2 and HPO4-2
Adrenal gland functions:
1. Helps control H2O and electrolyte balance
2. Helps control normal organic metabolism
3. Helps make body resistant to stress
4. Helps regulate sexual activity
axonal transport
can move at different speeds, both directions
Sensory neurons (afferent)
carrying information into central nervous system
Interneurons (association)
in between sensory and motor neurons
Motor neurons (efferent)
carrying information out of central nervous system out of body
Glial cells
supporting cells
Types of glial cells:
Schwann cells
make myelin in PNS
make myelin in CNS
span between blood vessel and neuron, pick up nutrients and transfer to neuron
wander around and get rid of foreign cells, damaged, perform phagocytosis in CNS
when something that is charged (ions) moves
Separating charges
potential energy, ex battery
current that is doing the work
how hard it is for charges to move; impedence or hinderance to current flow
Ohm's Law
Voltage = current x resistence

V = I x R
Ions move because:
-opposites attract/likes repel (electrical gradient)
-concentration gradient
Resting membrane potential
-all cells have
-inside of cell is more negative than outside of cell
-different cells have different amounts
Electrical gradient
wants Na+ and K+ into cell
Concentration gradient:
wants Na+ into cell and K+ out of cell