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365 Cards in this Set

  • Front
  • Back
What is physiology?
The study of how an organism works.
What are the two approaches to studying physiology and what are they?
teleogy - why?
mechanisitic - how?
What are the two processes of physiology adn what are they?
structure - anatomy
function - method
What is the biological organization hierarchy?
single cell - basic unit of life
tissue - populations of cells with the similar structure and function
organ - collection of tissues dedicated to a bodily function
organ system - interacting organs
What is the goal of biological organization?
to maintain an optimal internal environment of concentration of nutrients (able to deal with an influx/deflux in a timely manner), O2, CO2, waste products, pH, temperature, water/salts
What is homeostasis?
mantainence of a relatively constant internal envornment
How many cells interact with the outside env in a single celled organism?
all are in direct contact
How do cells in a multicellular organism respond to the ext env?
very few cells are in diret contact,
What is the cells environmect termed?
the interstitual fluid
What is in the extracellular fluid?
RBC/plasma and intersitsual fluid
How do organs optimize the interstitual fluid? (homeostasis)
cell specialization - seperate compenants to function
communication - infor flow (chemical and electrical)
intergration - function as a whole
How does homeostatic regulation work?
network of body componenets: detect deviation from normal, integrate info with other systems, make approp. adjustments, negative feedback = stop response when approp.
What happens when homeostatic reg fails?
pathophysiology, disease or illness
How does homeostasis work in vertebrate thermostasis?
the hypothalamus, org. center of the brain generates a temp set point: the body loses too much heat/ not enough, thermorecpetors send message to hypothalamus, adjust body temp (sweat if too hot, shiver if too cold), shut off mech when the set point is reached
How are cells compartimentalized?
cell membrane, nuclues, the cytoplasm (cytosol = fluid, organelles = membrane bound organelles, inclusions = non-membrane bound organelles such as ribosomes, cytokeleton, centrioles)
What is the function of cells?
to control info, process info, energy, scavenging system, and support + movement
How do cells control info?
occurrs in nucleus where DNA is stored, duplicated, and expressed. the nucleolus (dense DNA) synthesizes robosomes. the nuclear envelope has nuclear pores.
How does the cell process info?
smooth and rough ER and golgi apparatus.
What is the function of the rough ER?
the rough ER is studded with ribosomes. is synthesis, midifies, and transport proteins.
What is the function of the golgui apparatus?
it acts as a post office. sends proteins to the plasma membrane, vesicles, or lysosomes.
What is the function of the smooth ER?
it is a multipurpose organelle. synthesis lipids and acts as an enzyme to metabolize glycogen, detoxify drugs, and steroid synthesis.
How does the cell obtain energy?
mitochondria
What are the scavening systems of the cells?
lysosomes - low pH to breakdown molecules, recyyle old
peroxisomes - detoxify
What is used for support/ movement in the cell?
microtubles, intermediate filaments, actin filaments
What are microtubles?
made of tubulin. largest. provide structure for cilia/ flagella (only found in human sperm in a 9 + 2 arrangement). cell division by pulling chromosome to opposite sides. trank for motor proteins (railroad for nuerons)
What are intermediate filaments?
made of keratin. it is the cell scaffold. criss cross to hold the shape of the cell and organelles in place.
What are actin filaments?
cell shape, movement
What hold cells together?
cell to cell junction = holds cells together, cell matrix junctions= cytoskeleton interacts with extracellular functions
What types of cell-cell junction exist and what are they?
desmosomes- anchor two cells together. resist shearing (heart muscle, sking) cell adhesion molecule (CAM, cadherin)
tight junction- prevent material from going between cells and establish a polarity (creates a barrier with protein seperated)
gap junction- communication
What are the cell-matix junctions purpose?
focal adhesions or CAM, intergin, acts as a bridge linking actin inside cell to matrix molecules outside the cell (fibronectin, poleoglycans)
What types of tissues are there?
epithial, connective, muscle, nervous
What are epithial tissues?
Epithial tissues are any tissue that seperates the external and internal env. They can be simple (single layered) or stratified (many layers. sit on the basal lamina.
What are the types of epithial tissue?
exchange, transporting, protective, ciliated, secretory
What are exchange (epithial tissure)?
simple. rapid passage. blood vessles/ lung tissue.
What are transporting (epithial tissure) ?
simple. selective passage. digestive/ kidney.
What are protective (epithial tissure) ?
stratified. prevent passage. skin, mouth, urogential tract.
What are ciliated (epithial tissure) ?
simple. coordinate movement. clia beat rhythmically on the respiratorty tract to have mucus to come up.
What are secretory (epithial tissure) ?
simple. secret to the exterior. exocrine = secret ot he outside, sweat mucus and stomach acid. endocrine = secret tot he interior, hormone.
What hold cells together?
cell to cell junction = holds cells together, cell matrix junctions= cytoskeleton interacts with extracellular functions
What types of cell-cell junction exist and what are they?
desmosomes- anchor two cells together. resist shearing (heart muscle, sking) cell adhesion molecule (CAM, cadherin)
tight junction- prevent material from going between cells and establish a polarity (creates a barrier with protein seperated)
gap junction- communication
What are the cell-matix junctions purpose?
focal adhesions or CAM, intergin, acts as a bridge linking actin inside cell to matrix molecules outside the cell (fibronectin, poleoglycans)
What are connective tissues?
cells and extracellular matrix
What kind of cinnective tissues are there?
extracellular matrix, loose connective, dense connective, cartilage, bone, blood
What is extracellular matrix(connective tissue)?
composed of ground substance (ground poteoglycans/water) and protein fibers (collagen)
What is loose (connective tissue)?
cells: macrophage, mast cell ( immune cell, allergies), fibroblasts (secret collagen). mostly ground substance with some collagen. supports epitheilia: skin, blood cells, organs, what the epithilia sits on.
What is dense (connective tissue)?
cells: fibroblasts. little ground substance mostly collagen. makes up ligaments (bone to bone) and tendons ( bone to muscle.
What is cartilage (connective tissue)?
cells are mostly fibroblasts, chondroblasts = secret polysaccarides chondroit. closely packed collagen
What is bone (connective tissue)?
calcified collagen fibers
What is blood (connective tissue)?
cells; erythrocytes (rbc) and leukocytes (wbc). matrix: plasma (fibrogen, albumin, anitbodies)
What is the cell membrans?
proteins lipids carbs
What does the cell membrane do?
structure, function, homeostasis + dynamic disequilibirum, transport
What is the structure of the cell membrane?
phospholipid bilayer with cholesterol can be good or bad. intergral membrane proteins which can spawn the width od the protein. glycoproteins - GA, glycolipids, sphingolipid.
What is the function of cell emebranes?
to be a pysical barrier to the outside by onle letting certain molecules in by the communication with the recpectors.
How does the cell membrane assist in structural support?
the cytoskeleton interacts with the membrance protein. cell-cell and cell-matriz junctions.
How does the cell membrans assist in homeostasis and dynamic disequilibirum.
osmotic equilibrium = water freely passes. chemical disequilibrium = major solutes concentrate on one side. electircal disequilibrium - charge seperates across the membrane.
How does the cell membrans assist in transport?
diffusion, protein mediated transport
What is diffusion?
Diffusion is rare and depends on the membrane polarity, size of the molecule, lipid solubiulity, and composition of the membrane. measured by ficks law.
What is Ficks law?
rate of diffusion (amount/time) = [surface area * conc. of sub. * membrane perm] / membrane thickness
What are the types of protein mediated transport?
membrane transporter, facilitated diffusion, and active transport
What are membrane transporters?
channel protein form a pore in the membrane [can be open (mostly open) or gated (mostly closed)]. carrier proteins.
What type of gated membrane transporters exist?
chemically - molecule influenced
voltage - charged influenced
mechanically - force influenced
What are carrier proteins?
bind to the substrate and change the confromation. uniport - goes ony way, cotransport - goes two ways: together or anti.
What is facilitated diffusion?
no input of enrgy is required such as glucose being transported into/ouside the cell.
How does glucose transport work?
GLUT carriers - glucose is modified upon entry of the cell by phosphorylation.
What is active transport and what types exist?
Active transport uses energy, ATP, to move molecules gainst their concentration gradient. Primary and Secondary.
What is primary active transport and give an example?
direct ATP hydrolysis. NA/K pump. 3 NA bind, ATP hydrolized and changes conformation, NA released, 2 K ions bind, phosphate removes, confrom change, K released.
What is secondary active transport and give example?
indirect use of ATP. first molecule is transported against thier gradient. the second molecule is transported using the energy from the first. sodium/ glucose transporter.
What types of vascular transport are there?
phagocytosis, recepter mediated endocytosis, transepithial transport.
What is phagocytosis?
ingestion of large particles. actin polymerization surrounds particle
How does receptor mediated tansport work?
the receptor binds to the logand. the complex migrates to the "clathrin coated pit" which satbilizes the complex. the clathrin dissociates and what is left is the endosome. pH drops. endosome fuses w GA or lysosome, recycles receptors.
What are transepithial trnasport?
the protein spawns the whole membrane. involves the use of tight junctions.
What is the purpose of tight junctions in transepithial transport?
establishes a membrane polarity. Na/glucose symporteron apical surface, glut transporter basolateral, [Na} high in lumen extracellulary and [glucose] high intracellularly.
What is the mechanism of Na/glucose transport?
Na/glucose symportter take glucose in (against conc.) along with Na (along conc). glucose diffuses passively across basilateral surface (GLUT)
How does glucose not get used for energy in transepithial transport?
glucose does not get phosholyated for energy bc we use amino acids so glucose does not get phosphoeylated so it can form a concentration rgradient.
What is osmosis?
water crosses a membrane in response to a solute grad.
What is osmotic pressure?
the force required to oppose osmosis
What is osmolarity?
# of particles/ L of solution.
What does osmolarity depend on?
on the number of particles, not composition or the number of molecules.
How can we compare solutions?
osmalirty, tonicity, prenetratiting vs. non- penetrating.
What does isomotic mean?
solution A is the same to solution B. same number of particles.
What does it mean for a solution to be hyperosmotic?
solution a has more particles than solution b.
What does it mean for a solution to be hypoosmotic?
solution a has lessparticles than solution b.
What does tonicity mean?
how solution affects the cell volume.
What does it mean for a solution to be isotonic?
cell stays the same size
What does it mean for a solution to be hypertonic?
the cell decreases in size
What does it mean for a solution to be hypotonic?
the cell increases in zise
What does tonicity depend on? why?
tonicity depends only on non-penetrating solutes becuse non- penetrating solutes stay where they are.
What is the resting membrane potential and who are the key players?
the charge differnce across the membrane.
K+ high inside
Na+ high outside
Cl- high outside
Ca++ high outside
What is an electrochemical gradient?
relative inbalance of K+ across membrane, which is the main factor for setting up the resting membrane potential.
What does resting mean in the resting membrane potential?
steady state distribution of charge
What does potential mean in the resting membrane potential?
stored energy
What occurs in a resting cell?
Na/K pump, cell has open K channels, few open Na channels, protein neg. charges cant cross the membrane, and the resting membrane potential is about -80 mV.
What is ion equilibrium potential?
point at which no net ion flow occurss bc force of the chem grad is equal to the force of electrostatic grad
What is the Nernst equation?
Ek = -61.5 log {[Koutside]/[Kinside]}
Why is a resting cell equal to about -80 mV?
K ion channels are open, K continually leaves out of the cell, few Na channels open.
Why do cells communicate?
to maintain homeostasis. hormone activity, immune cell acitivation, nerve impulses, muscle contractin, cell growth/differentiation, modify body metabolism.
How do cells communicate?
gap junction - fre flow of info, contant dependent (immune cells, B ant T cell activation), molecule release leads to receptro binding.
What kinds of molecule release/ receptor binding exist?
autocrine signal - binds to the cell that secrets it. paracrine - binds to cell in immediate vicinity. longer distances we use endocrine cells which secret hormones or neurons which scret neurohormones.
How is a respone from communication transduced?
the signal molecule binds to a recpetor, binding activates intracellular molecules, signalling molecules leads to target protein or gene expression.
What types of receptors exist?
cytostolic or nuclear receptors (lipophilic molecules) and cell membrane receptors(lipophobic).
What occurs in cytostolic or nuclear receptors and quick is it?
receptor binds to nucleus bind to "hormone response hormone" and gene expression results. slow process.
What are the four categories of cell membrane receptors.
ion channels , receptor/ enzyme activates enymatic activity, G-protein coupled receptors, integrins
WHat are ion channels?
(chemically gated) - neurotansmitters
WHat are receptor/ enzyme activates enymatic activity?
kinase activity, adds a P (turosine kinase)
WHat are G-protein coupled receptors?
largest class, also called 7 transmembrane recpetors, singal indirectly via GTP - bound intermediates (hormones, neurotransmitters, phontons)
WHat are integrins?
cytoskeleton rearragnements
What are signal transductions?
transmits info and amplifies response
What kinds of signal transduction exist?
primary messengers and G-protein coupled signal transduction
What are primary messengers?
the ligand binds to the receptor and leads to kinase activation, adds a P to porteins which usually results in altered gene expression, or it and acitivate secondary messengers which alter ion channel gating, increase intracellular Ca which modulates protein activity and calmodulin.
Why do cells communicate?
to maintain homeostasis. hormone activity, immune cell acitivation, nerve impulses, muscle contractin, cell growth/differentiation, modify body metabolism.
How do cells communicate?
gap junction - fre flow of info, contant dependent (immune cells, B ant T cell activation), molecule release leads to receptro binding.
What kinds of molecule release/ receptor binding exist?
autocrine signal - binds to the cell that secrets it. paracrine - binds to cell in immediate vicinity. longer distances we use endocrine cells which secret hormones or neurons which scret neurohormones.
How is a respone from communication transduced?
the signal molecule binds to a recpetor, binding activates intracellular molecules, signalling molecules leads to target protein or gene expression.
What types of receptors exist?
cytostolic or nuclear receptors (lipophilic molecules) and cell membrane receptors(lipophobic).
What occurs in cytostolic or nuclear receptors and quick is it?
receptor binds to nucleus bind to "hormone response hormone" and gene expression results. slow process.
What are the four categories of cell membrane receptors.
ion channels , receptor/ enzyme activates enymatic activity, G-protein coupled receptors, integrins
WHat are ion channels?
(chemically gated) - neurotansmitters
WHat are receptor/ enzyme activates enymatic activity?
kinase activity, adds a P (turosine kinase)
WHat are G-protein coupled receptors?
largest class, also called 7 transmembrane recpetors, singal indirectly via GTP - bound intermediates (hormones, neurotransmitters, phontons)
WHat are integrins?
cytoskeleton rearragnements
What are signal transductions?
transmits info and amplifies response
What kinds of signal transduction exist?
primary messengers and G-protein coupled signal transduction
What are primary messengers?
the ligand binds to the receptor and leads to kinase activation, adds a P to porteins which usually results in altered gene expression, or it and acitivate secondary messengers which alter ion channel gating, increase intracellular Ca which modulates protein activity and calmodulin.
How deso G-protein coupled signal transduction work?
a receptor physically links to a G-protein, heterotimeric is bounds to GDP in inactive form, the signal activates G protein by exchanging GDP for GTP, G protein activates the amplifying protein (adenyl cyclase).
How does the G protein-coupled adenylyl cyclase-cAMP system work?
the ligand binds to the g protein-linked recpetor which activates the G protein, G protein turns on adenylyl cyclase an amplifier enzyme, adenylyl cyclase converts ATP to cyclic AMP, cAMP activiates protein kinase A, protein kinase A phosphorylates other protein leading to a cellular response (change in the metabolism of the cell).
How deos G protein-coupled receptors also use lipid-derived second messengers?
the lignad binds to the G protein coupled recpetor, G protein activates phospholipase C (PL-C)an amplifier enzyme, PL-C converts a membrane phospholipid to diacylglycerol (DAG, remains in the membrane) and inotsitol trisphospahate (IP3, diffuses in the cytoplasm). DAG activates protein kinase C which phosphorylates protein downsteream. IP3 binds to calcium adn releses Ca from the ER, Ca creates signals. both signals do cell proliferation, vesicle secretion, alter metablosm, apoptosis, progrmaed cell death.
What are other types of signalling molecules?
dissolved gases such as nitric oxide. eicosanoids.
What does CO2 do to the cell?
they are short lived so act locally (paracrine signals) and cross membranes. immune function of inflammation.
What does eicosanoids do to the cell?
lipids, short lived. these signals activate phospholipase A2 which forms arachidonic acid (AA, membrane lipids). AA to lipoxygenase to leukocytes (inflamm) or AA to cyclogenases to prostoglandins (pain and fever).
How are signal transduction pathways controlled and regulated?
antaonisctically, up and down regulation
How do antagonistic regulation work, example?
blocks receptor activity. interleukin: IL-1 activates immune cells and IL-alpha binds and stops IL-1 signal.
How does Up and down regulation work?
physically remove it from the membrane, functionally: modify so less active (desensitization), modify/remove effectors: G protein GTP to G protein GDP or remove CA++ from cytoplasm.
How deso G-protein coupled signal transduction work?
a receptor physically links to a G-protein, heterotimeric is bounds to GDP in inactive form, the signal activates G protein by exchanging GDP for GTP, G protein activates the amplifying protein (adenyl cyclase).
How does the G protein-coupled adenylyl cyclase-cAMP system work?
the ligand binds to the g protein-linked recpetor which activates the G protein, G protein turns on adenylyl cyclase an amplifier enzyme, adenylyl cyclase converts ATP to cyclic AMP, cAMP activiates protein kinase A, protein kinase A phosphorylates other protein leading to a cellular response (change in the metabolism of the cell).
How deos G protein-coupled receptors also use lipid-derived second messengers?
the lignad binds to the G protein coupled recpetor, G protein activates phospholipase C (PL-C)an amplifier enzyme, PL-C converts a membrane phospholipid to diacylglycerol (DAG, remains in the membrane) and inotsitol trisphospahate (IP3, diffuses in the cytoplasm). DAG activates protein kinase C which phosphorylates protein downsteream. IP3 binds to calcium adn releses Ca from the ER, Ca creates signals. both signals do cell proliferation, vesicle secretion, alter metablosm, apoptosis, progrmaed cell death.
What are other types of signalling molecules?
dissolved gases such as nitric oxide. eicosanoids.
What does CO2 do to the cell?
they are short lived so act locally (paracrine signals) and cross membranes. immune function of inflammation.
What does eicosanoids do to the cell?
lipids, short lived. these signals activate phospholipase A2 which forms arachidonic acid (AA, membrane lipids). AA to lipoxygenase to leukocytes (inflamm) or AA to cyclogenases to prostoglandins (pain and fever).
How are signal transduction pathways controlled and regulated?
antaonisctically, up and down regulation
How do antagonistic regulation work, example?
blocks receptor activity. interleukin: IL-1 activates immune cells and IL-alpha binds and stops IL-1 signal.
How does Up and down regulation work?
physically remove it from the membrane, functionally: modify so less active (desensitization), modify/remove effectors: G protein GTP to G protein GDP or remove CA++ from cytoplasm.
What are the control systems for response and feeback loops?
inout signal (change in variable) to the controller (integration center) to the output signal (effector)
What are the methods for effector control?
tonic control - up through down over a "range"
antagonistic control - control "a" or "b" (heart rate reg)
Hwat is the reflex control system in the response and feedback loops?
coordination of respons lies outdside locality of repsonse. response loop.
What are the receptor cells in nueral control?
specialized cells that respond to a change
What are the afferent pathways in nueral control?
electircal signal
What are the intergrating center in nueral control?
CNS brain and spinal chord
What are the efferent pathway in nueral control?
electrical signal
What are the efector in nueral control?
cellular response
What are the receptor cells in endocrine control?
endorine cell
What are the afferent pathway in endocrine control?
none because everything happens in the cell itself
What are the integration center in endocrine control?
endorine cell
What are the efferent pathway in endocrine control?
hormones
What are the effector in endocrine control?
cellular response
What is the specifity in neural cells?
high
What is the nature in neural cells?
electrical and chemical
What is the speed in neural cells?
very fast
What is the duration in neural cells?
short
What is the intensity in neural cells?
all or none
What is the specifity in endocrine cells?
low
What is the nature in endocrine cells?
chemical
What is the speed in endocrine cells?
much slower
What is the durationmin endocrine cells?
long
What is the intensity in endocrine cells?
depends on the amount of hormone released.
What is the organization of the nervous system?
central nervous system (CNS): brain and spinal chord (integrating center for neural reflexes) and the Peripherial Nervous System.
What are the neurons invloved in the PNS?
afferent neurons - take info from receptors to the CNS.
efferent neurons - take info form the CNS to the effectors.
What kinds of efferent neurons are there?
somatic motor division which voluntailry controls skeletal muscle and the autonomic division whih is involuntray (smooth, cardiac muscle, digestion, urinary, reproductive, etc.)
What kind of autonomic divisions exist?
sympathetic branch: fight or fligth (stress, increase heart rate, slowing digestion, dialate vessles ti muscles, liberate nutrients).
parasympathetic - day to day functionc (rest and digest, lower heart rate, inc digestion, store nutrients)
What are the cells of the nervous system?
neuron, glial
What is a neuron?
a functional unit composed of a cell body - nucleaus, prganells,
What extend from a neuron?
dendrites - receive incoming info and tramnsfer to integrating region (trigger zone)
axon - carry outgoing signals and end in the axon termini where neurocrine is released.
What type of neurons exist?
sesory (afferent), interneurons (CNS), and efferent neurons (go to effector or target)
What are glial cells?
accessory cells which provide support and nourishment. found in cns and pns.
What kind of glial cells are foudn in the CNS?
oligiodendrocytes, astrocytes, microglia, ependymal
What are oligiodendrocytes?
myelin sheaths around axon for insulation (protection) and faster propagation.
What are astrocytes?
"sense environment of CNS. provide structural support (make matrix), metabolic help, ion balance, guide blood vessels in bllod-brain barrier.
What are microglia?
modified macrophages for immune function
What are ependymal?
line hte CNS cavity, they are ciliated to move the cerbrospinal fluid. could be the source of nueral stem cells.
What kind of PNS glial cells exist and what are they?
schwann cells: myelinated
satellite cells: protectin groups of neuron cell bodies, ganglion.
How many ions are needed to change membrane potential?
very few
How does the ion concentration inside/ outside the relate to each other?
remain relatively unchanged
Neuron potential involves what?
a graded potential and action potentials.
What are graded potentials?
chemically gated Na channels open in response to excitatory signal, the stimulus travles like a wave that loses stregnth.
What is the source of a signal in a graded potential?
sensory neurons: mechanical, molecular, sound, photons
Where do chemical signals come from?
CNS and efferent and other neurons
What is the trigger zone?
where the signals meet unitl the threshold membrane potential is reached at which the signal continues.
Where is the trigger zone in the efferent and sensory neurons?
in the sensory neurons where the dendrites join to the axon. in the efferent neurons where the axon hillock-first part of the axon.
What occurs in an action potentials?
voltage gated Na channels open when the threshold is reached.
Does the action potential mantain the same strength?
Yes, it is an all or none process.
The complexity of the decision to fire an action potential?
number of ion channels, isoform of ion channel protein, threshold voltage, gating speed.
Whata re the events of an action potential?
The resting potential stimulus has been received at the dendrites, the graded potential reached the trigger zone or reaches threshold, the voltage gated Na channels open to cause an Na influx along chemical and electrical gradientm the influx continues past 0 mV until it reaches equilibrium potential is reached, Na channels close a 30 mV, Na permeability stops, the voltage gated K channels open depolorization but more slowly tha NA channels, efflux of K leaving the cell repolarizes the membrane, K channelse still open at resting potential "under shoot" (hyperpolarization), K channels close adn return to resting potential.
How many gates to voltage gated Na channels have?
2 gates
At the resting potential when are the gates open/ closed?
open - inactivation
closed - activation
What happens when the threshold is reached at a voltage gated NA channels?
activation: the gates open, the cell continues depolizing, inactivation closes the gates and is delyaed by less than 1 msec.
What are the distuishing charachteristics of action potentials?
refractory period, translating stregnth of orinigal stimulus
What kinds of refractory periods exist and what are they?
absolute refractory - additional AP is not possiblel Na channels have not reset
relative refractory - some Na channelse reset, but need a stronger graded pot.
What makes the translasting strength of the original stimulus faster?
The higher the strength of the graded pot, higher rate or AP firing, more neurotransmitters released.
What is propagation in voltage gated Na channels?
propagation is the local current flow. AP does not loose strength and moves in one direction. the positive charges move adjacent to a depolarized segment causing neighboring Na channels to open, inactivating Na channels (behind), absolute refractory includes no backward movement of AP.
What are the two ways to increase the speed on an AP?
increase diameter so less resistance or saltatory conduction
What is saltatory conduction?
myelinated axon. leakage of ions slows the AP: myelin insulates the membrane. depolorization at non-myelinated region (node of Ranvier) is suffiecient to depolorize the next node of ranvia so the AP jumps from one node to the next.
What is a presynaptic cell?
neuron that transmits info to the postsynaptic cell (nueron, effector)
What is the synapse?
the connection between the pre and post-synamptic cell
What is the synaptic cleft?
the space between the pre and post-synamptic cell.
What is a neurotransmitter?
it is a chemical signal. the neurotransmitters are held in vesicles: waiting for the exocytosis signal.
How many ions are needed to change membrane potential?
very few
How does the ion concentration inside/ outside the relate to each other?
remain relatively unchanged
Neuron potential involves what?
a graded potential and action potentials.
What are graded potentials?
chemically gated Na channels open in response to excitatory signal, the stimulus travles like a wave that loses stregnth.
What is the source of a signal in a graded potential?
sensory neurons: mechanical, molecular, sound, photons
Where do chemical signals come from?
CNS and efferent and other neurons
What is the trigger zone?
where the signals meet unitl the threshold membrane potential is reached at which the signal continues.
Where is the trigger zone in the efferent and sensory neurons?
in the sensory neurons where the dendrites join to the axon. in the efferent neurons where the axon hillock-first part of the axon.
What occurs in an action potentials?
voltage gated Na channels open when the threshold is reached.
Does the action potential mantain the same strength?
Yes, it is an all or none process.
The complexity of the decision to fire an action potential?
number of ion channels, isoform of ion channel protein, threshold voltage, gating speed.
Whata re the events of an action potential?
The resting potential stimulus has been received at the dendrites, the graded potential reached the trigger zone or reaches threshold, the voltage gated Na channels open to cause an Na influx along chemical and electrical gradientm the influx continues past 0 mV until it reaches equilibrium potential is reached, Na channels close a 30 mV, Na permeability stops, the voltage gated K channels open depolorization but more slowly tha NA channels, efflux of K leaving the cell repolarizes the membrane, K channelse still open at resting potential "under shoot" (hyperpolarization), K channels close adn return to resting potential.
How many gates to voltage gated Na channels have?
2 gates
At the resting potential when are the gates open/ closed?
open - inactivation
closed - activation
What happens when the threshols is reached in a voltage gated Na channel?
acitvation opens the gates, the cell continues to depolarizwe, inactivation closes the gates which is delayed by less than 1 msec.
What are the distinguishing chrachteristics on an AP?
refractory periond, translatinf strength of oringinal stimulus?
What kind of refractory preiod exists?
absolute - additional AP is not possible sine Na channels have not yet reset.
relative - some Na channels reser nbu need a stronger graded pot to refire
What happens when the strength od the original stimiuls is translated?
the higher the strength of graded pot, is higher rate of AP firing, more neurotransmittesr release.
What is propagation>
local current flow. AP does not loose stregnth, AP moves in one direction.
How does AP move in one direction?
positive charges move adjacent to a depolarized segment, causes neighboring Na channels to open, inactivated Na channels (behind). no backward movement of AP.
What is a presynaptic cell?
neuron the transmits info to postmsynaptic ell.
What is a synapse?
connection between the pre and postsynaptic cell.
What is the synaptic cleft?
the space between the pre and postsynaptic cell.
What are neurotransmitter?
chemical signal released into the synaptic cleft. a nt is held in the veiscle watiing offr an ecocystosis signal.
What occurrs at the synapse?
Ap reahces the axon terminus, voltage gated Ca++ channels open, Ca++ goes into the cell, Ca++ influx signals vesicle fusion with membrane, nt. released to synaptic cleft, binds recpetors on post-syn membrane.
What kind of neurotransmitters exist?
acetylcholine, amines, and amino acids.
Give an example of acetylcholine, where it is secreted by/ receptor fro, where?
acetylcholine, cholinergic, CNA+autocrine
Give an example of amines, where it is secreted by/ receptor fro, where?
norepinephrine, adrenergic, CNS+sympathetic
Give an example of amino acids, where it is secreted by/ receptor fro, where?
GABA, GABA, CNS-main inhibotroy.
What are the classes for receptors for nt?
cholinergic (bind ACh), adrenergic (sympathetic)
What are example of cholinergic?
nicotinic: skeletal muscle (cation ion channels)
muscarinic: CNS, parasympathetic ( G protein coupled channels)
What are examples of adrenergic?
sympathetic, bind norepinephrine, G protein coupled receptors.
What are the effects of receptors for nt?
fast synaptic potential: quick short responses (ion channels)
What kinds of synaptic potential are their and what are they?
excitatory post syn potential (EPSP)-depolarizes events that induce AP
inhibitory post syn potential (IPSP)-hyperpolarize
slow post syn potential-slow acting, longer lasting.
What kinds of synaptic potential are invloved in g protein coupled responses?
EPSP, IPSP
What is an nt turnover?
signal is hort in duration, breakdown of nt in synaptic cleft - ACh, recycle back to pre-synaptic cell
What deos the intergration of information center include?
at the neuron level their are many inputs for one output. the modulation of AP activity: deicision to fire AP or not.
Does it matter how many input messages there are?
no, the AP is yes or no
Can the networks of the neurons fine tune a response.
yes, either with convergence (many pre-syn neurons contact smaller numbner on the post syn) or divergence(small number of pre-syn contact larger number of post syn).
What does modualtion include?
summation and inhibtion
What are the two types of summation and what are they?
temporal - quick succession of graded pot.
spatial - simulataneous graded pot from diuffer pre-syn neurons
What are the two types of inhibition and what are they?
post synaptic inhibition-release of inhibitory nt (GARA) at postsynaptic cell synapse and all target cells are equally affected
pre synaptic inhibition- modulatory neuron synapse at the axon terminal, selective inhibition of target cells.
What does the brain develop from?
a hloow tube
What deos the brain consist of from the outside in?
cranium, meninges, tissues
What is the cranium?
shull
What are the three meninges layers of the brain and what are they?
dera meater - thick connective tissue. arachnoid - subarachnoid space contains cerebrospinal fluid (CSF), weblike. pia meter - surface of the brain tissue (lionks the CSF and the ECF).
What are the tissues in the brain?
gray matter - unmyelinated. white matter - myelinated
What deos the brain do in the CSF?
floats
What are the teo functions of the CNS?
physical protection, nutrient supply
How many anatomical spaces are there in the ventricles?
4
What do the ventricales contain and what do they do?
contain the charoid plexus which secrets CSF
How deos the CSF flow?
the CSF flows into the subarachnoid space, circulates to brain and spinal cord and returns by the blood stream.
Why is there a blood-brain barrier?
capillaries are isolated from nueral tissue.
How is the bllod-brain barrier seperated?
tight junction in endothelial cells promote very slective movement
What diffuses freeely across the blodd-brain barrier?
O2 diffuses freely.
How is the blood barin barrier so selective?
induced by astrocyte processes, and the only movement between the bloos -brain ECF is through specific carriers/
What is the spinal chrod encased in?
vertebrates
What is at each segment of the spinal?
spinal nerves
Waht is the function of spinal nerves?
sensory info: dorsal roots and outgoing info: ventral roots branch out from the spinal chord
What type of sensory infro are there in the spinal chrod?
afferent neurons branches to ht epsinal chord. and ganglia: collection of cell bodies.
What kind of matter exists in the spinal chord?
gray (sensoty and efferent neuclei, collection of cell bodies) and white (axonial extensions).
What kinds of gray matter exists?
afferent:dorsal horn
efferent: ventral horn
What kinds of white matter exists?
ascending tracts: to brain
descending tracts: from brain
What are the brains functional regions?
brain stem, cerebellum, diencaphalon, cerebrum.
What is the brain stem function?
link between the spinal chord and brain. reticular for motions - diffuse network of neurons for sleep/arousal.
What are the specific regions of the brain stem and what are there functions?
medulla oblangata: tracts cross to opposite side. puns: relay between cerebrum and cerebellum. mesenchephalon: eye movement.
What is the cerebellum?
coordination and movement
What is the diencephalon?
homeostatic control
What are the specific regiong of the diencephalon and what are their function?
thalamus: integrating center ofr sensory info. hypthalamus: homessattic center. pituitary and pineal glands: hormones. corpus collosumn: crossover axons for two hemisphere
What is the cereburm?
higher brain functions
What are the two types of tissue founf in the cereburm?
gray and white matter
What are the specific regiong of the gray matter and what are there function?
5%. cerebral cortex: outer layer of cereburm (all comes here intially, divided into functional sections: can be hemisphere specific). basal ganglia: movement. limbic system: learning, emtion, memory.
What are the specific regiong of the whitematter and what are there function?
95%. most of the interior. cerebral cortec: inter-communication.
What are the functional regions of the cerebral cortex and what are their function?
primary motor complex: plans/executes movement by working with basal ganglia and cerebellum to coordinate movement, primary somatic sensory cortex: info from skin, skeletal muscle, internal organs.
What do sensory systems involve and what are they?
receptors, connecting stimulus into change in membrane potential
What is a receptor potential?
graded stimulus that can cause threshold to be reached.
What is threshold?
minimum stimulus required to activate receptor
What is primary receptor field?
physical area to which receptors responds.
What are secondary receptor fields?
multiple primary receptor fields overlap.
How does convergence affect the sensitivity to a stimulus?
the less convergence, the more sensitivity
Where are all sensory stimuli integrated?
CNS
How does the brain distinguish stimuli?
modality (general): type of stimulus where the pathway ends in the brain, location (specific): highly organized regions differ types go to differ regions, intensity: strength of stimulus results in more AP/time, duration: length of stimulus or more sustain AP firing.
What does the somatic sense pick up?
touch, temp, pain, orientation.
What is the primary pathway of somatic senses?
the primary neurons go to the spinal cord where they synapse with secondary neuron, cross midline, to thalamus. or it can continue to the medulla, synapse with seconday neuron, cross the midline to thalamus
What do tertiray neurons do?
take info to primary somactic sensory cortex
What does the area of perception depend on?
sensitivity of the body part
What kind of of somatic cells exist for touch?
several types, depends on the stimulua
What are nociceptors?
sense pain the in the skin
How are nociceptors activated?
physical stimulus (heat or touch). chemical stimulus at the site of inflammation.
What is fast pain?
sharp, loclaized - large myelinated axon
What is slow pain?
slow dull pain - small, non-myelinated axon
What is a withdraw relex?
primary neurons synapse in spinal chord, return to stie of stimulus.
What are the special senses?
chemoreception (smell, taste), mechanoreceptors (pressure = hearing), photoreception (vision)
What are the cells used in chemorecption smell and describe them?
olfactory cells (neuronal) have dendrited with odorant receptors, unique for each olfactory cell, receptors are G protein coupled with cAMP seconday messengers, open ion channels in membrane.
Where do secondary neurons converge?
olfactory bulb
What are glomeruli?
specific groups of primary synapses with secondary neurons
What are the cells used in chemorecption taste and describe them?
papillae: raised bumps that contain taste buds. each bud has about 50 taste cells (epithial cells release nt), apical ends have taste receptros.
How many taste receptors exist for a taste cell?
1.
How do taste receptors work?
G protein-coupled: bitter, sweet, umami. ion channels: sour, salty. net result ig a Ca++ unflux, release of nt.
How do mechanoreceptors function?
the ear is in equilibrium. vestibular complex sense acceleration. semicircular cnalas sense head position in space. hearing is done in the outer adn middle ear and cochlea.
What is hearing?
the perception of pressure waves (frequency and amplitude).
What is pitch?
pitch=frequency= hertz (Hz)= waves/sec. loudness
What is loudness?
amplitude or decibels
What are the steps in sound perception?
mechanical: sound waves translated to vibration in the eardrum by 3 bones, fluid waves: oral window vibrates to produce flui waves in cochlea, chemical signals: hair cells in cochlea release nt to neurons, Ap is sent to the brain.
What is the cochlea?
fluid ducts.
What does the organ of corti do?
wave energy into an AP.
How do waves get turned into an AP?
fluid waves cause oscillation of tectorial emembrane and basilar membrane, acts on hair cells: non-neuronal receptors with stereocilia, in one direction the mechanically gated cation channels open and the membrane depolarizes, voltage gated Ca++ channels open and more nt released to the neuron, more nt release the more AP firing. if it goes in other directin the channel shuts down by hyperpolarization.
How can we tell different pitches?
temporal aspects are uturned into spatial coding. location on the basilar membrane displaced differently from different frequency.
What is the structure of the eye?
two chambers are seperated by a lens.
What are the two chambers and what are they?
Aqueous humer: support nutrients for cornea/lens. Vitreous humor: maintain shape.
How many ways can light go into the retina?
2
How and why does the eye contract?
the iris by contracting the circular muscle b/c of the amount of light.
Whatis accomodation?
focusing of light
How do we see far?
by letting the ciliary muscles relax and the lens flattens
How do we see close?
contract the ciliary muscles to see close
What is phototransduction?
converting light stimuli to nueral signals.
What are the three layers in the retina form the back to front?
rods: night/gray vision, cones: day/color vision. bipolar cells: postsynaptic cell fro rods/cones. ganglion cells: postsynaptic cell for bipolar cell.
What is the fovea and what does it have a hihg concentration of?
the exact center of the retina. cones.
How does the stimulation of rods and cons occurr?
light collect in the cells in the back of the retina which causes a hyperpolarization.
How does light collect in the back of the retina?
by g-protein receptors (opsin or by cofactor - retinal (absorbs light). rods: opsin + retinal = rhodopsin (1). cones: opsin + retinal = photopsin (3).
How does the hyperpolarization occurr in darkness?
cGMP-gated ion channels open because the [cGMP] is high so their is a constant Na influx which depolarizes the membrane. Na channels open and the nt are released to the bipolar cells
How does the hyperpolarization occurr in light?
retinal (pigment) is converted to an isomer form which activates a G-protein (transducin) whuch cleaves the cGMP, Na channels close causein a hyperpolarization and the nt release decrease
What is the nt from a rod or cone processed by?
bipolar or ganglion cell
What are the two repsonses to a nt release?
bipolar cells - light on: inhibited by nt, light off: activated by nt.
bipolar and ganglion cells - have receptor fields.
What are the two pathways for an efferent neuron and what are they?
autonomic: sympathetic and parasympatheic (cardiac, smooth muscle, glands. homeostasis. somatic motor pathway: skeletal muscle
What are the two pathways for an autonomic response?
afferent - somatosensory (touch, temp) and visceral (tissues, organs)
efferent - autonomic response: physiological, behavioral
What is the anatomy of an autonomic pathway from CNS in series?
preganglionic (myelinted from CNS) synapses with postganglionic nureon (unmyelinated to tissue). the synapse is referred to as the autonomic ganglia.
How does the sympatheic and parasympathetic branch form the CNS differently?
spinal cord location. symp: mid spinal cord, parasym: lower spinal cord. ganglionic structure. symp: ganglia close to spinal cord (short preganglia, long postganglia). paraym: have ganglia closer to the effector site (long pregangleon, short postganglia)
What is a twitch?
muscle fiber response to a single AP
What is a summation?
another twitch before the first one relaxes
What is a tetanus?
sustained meximal force
What is fatigue?
the inablilty to amintain constant froce?
What is are the two types of fatigue and what are they?
central-physcological
peripheral-physiological
What is isometric?
results in no muscle shortening
What is isotonic?
results in muscle shortening because the force exceed the load
What kind of neurotransmitters exists in efferent nuerons?
preganglionic neurons- relax ACh onto nicotonic recpetors
postganglonic - release ACh onto a muscarine receptros
What are neuroeffector junctions?
synapse of post-ganglionic with an effector
What are nueroeffectors in the sympathetic?
varicosities (swellings) along the axon termini
What are nueroeffectors in the para-sympathetic?
varicosities and axon termini
What is the pathway for a somatic motor?
single neuron from the CNS to the target muscle fiber (myelinated)
Where are the cell bodies in a somatic motor pathway?
in ventral horn or brain
What if a nueromuscular junction?
synapse of motor neuron with a muscle fiber.
What kind of nueromuscular junction exist for a presynaptic neuron?
ACh onto nicotonic receptors
What kind of nueromuscular junction exist for a postsynaptic neuron?
motor neurons end plates (clusters of receptors)
What are the three types of muscles?
skeletal- (straited)
movement, temp reg
smooth- (non-striated) internal organs (blood vessels, GI tract)
cardiac- (striated) heart
What make muscle fibers?
muscle cells
Is a muscle cell multi-nucleated?
yes
What do muscle cells consist of?
myofibrils- contractile unit, elastic fiber (action/myosin)
sarcoplasmic reticulum- stores Ca++, modifies ER
What is a sacromere?
repeating actin/myosin units
What is an a microfibril?
thick filaments-bundels of mysoin, held in place by elastic proteins (titon)
thin filaments-2 strands of actin, held in place by nebulin
sacromeres-characterized by visual patterns, bands
What are the molecular events of muscle contraction?
sacromeres shorten, cross bridge cycle, regulation of the cross bridge cycle, calcium is released from sacroplasmic reticulum.
What are the events of the croos bridge cycle?
current accepted model. myosin is tightly bound toa ctin, ATP binds to myosin adn the hydrolysis of ATP puts myosin head in active form, release of a P causes a power stroke, APP released which is tightly associated with actin
What regulated thecross bridge cycle?
the presence of calcium
How is the crodd bridge cycle regulated?
tropomyosin obscured myosin binding sites, Ca++ bingd to topinin which moves the tropomyosin from actin, the removal of Ca__ relaxes the muscle
Where is the Ca++ released from?
sacroplasmin reticulum
How is calcium released from the sacroplasmic reticulum?
motor neuron AP reaches the axon terminus, ACh released to motor cell plate, opens cation channels to depolarize the muscle fiber, impulse is carried through T-tubules, voltage gated receptors physically linked to SR.
What affects muscle performance?
twitches, vary the rate at wich the tension is developed,
What is a twitch?
one contraction-relaxation cycle in a muscle fiber
How can we vary the rate at which tension develops?
We can use slow or fast twitch fiber?
What are slow twitch muscle fibers?
10-30 twitches per sec, rely on oxidative phosphorylation fro ATP (36 atp/glucose), high myoglobing so faster rate of 02 diffusion, more capallaries, resist fatigue. posture and endurance.
What are fast twitch muscle fibers?
70-100 twitches per sec, rely on glycolysis (lactic acid) 2 ATP, low myoglobin, fewer capallaries, fatigue prone used for quick movement