animal physio exam one

what is the law of mass balance

if the amount is to remain stable, in the body, gain must be offset by loss

what is steady state

dissimilar composition between compartments maintained by energy input

what is equilibrium (against steady state)

similar composition between compartments that result when the driving force is zero

what is homeostasis and its maintanence

it is the maintanence of stable internal environment through steady state and law of mass balance

negative feedback

the response counteracts the stimulus, shutting off the response loop, restores the signal to set point

positive feedback

the response reinforces the stimulus, sending variable even further from set point

what is the relationship between specialized environment and overall function in. the body

the membrane transport maintains specialized environments of compartments which supports specialized functions of compartments

what is the relative concentration gradient across a cell membrane for ions K+, Na+, Cl- and Ca2+, large anions and proteins

only K+ is higher on the inside

what is the relative concentration gradient between plasma and IF for large anions and proteins

IF 75%, Plasma 25%

what are the three types of cell junctions and their functions

• gap junction: communicating

• tight junction: blocking

• destines: anchoring

what are the four types of tissues

• epithelial

• connective

• muscle

• neural

what defines an organ

all four tissue types, vital function, self contained

osmotic equilibrium

water may move freely between most cells

chemical disequlibrium

compartments are chemically different but solute concentrations are equal

how is water distributed throughout the body

osmotic equilibrium

what is osmotic pressure

pressure required to oppose osmosis

how does water cross the membrane

freely ; from high to low

what is osmolarity

the osmotic concentration

osmolarity = molarity x # of particles

what is tonicity

the effect of a solution on cell swelling and shrinking due to water movement

osmoloarity against tonicity

osmolarity predicts water movement

tonicity depends on concentration of non penetrating solute

ricks law of diffusion

rate of diffusion Is proportional to the surface area of a membrane, the concentration gradient, and membrane permeability

what determines whether a substance will cross the cell membrane

surface area, concentration gradient, membrane permeability

what affects diffusion and its rate

distance, temp, molecular weight, size

distinguish carrier from channel proteins

carriers do not form a continuous pathway between extra and intra cellular fluid

distinguish facilitated diffusion

uses a carrier

distinguish primary active transport

transport against concentration gradient using ATP directly

distinguish secondary active transport

energy indirectly from ATP

how does the Na+K+ATPase pump work

—>3Na+ out 2K+in

binding of Na+ inside causes phosphorylation and conformational change and release of Na+ outside

binding of K+ outside causes dephoshporlyation and conformational change and release of K+ inside

transport specificity

one molecule/group of related molecules

transport saturation

maximal velocity

competition

related molecules compete

phagocytosis

• vesticular transport

• actin mediated

• engulfing bacteria and foreign particles

receptor mediated endocytosis

• receptor ligand moves to clathrin coated pit and is internalized

• receptor and membrane recycled via exocytosis

caveloae

endocytosis using lipid rafts

pinocytosis

fluid endocytosis

how is glucose transported across epithelial cells (SGLT)

apical membrane

how is glucose transported across epithelial cells (GLUT and Na+K+ATPase)

basolateral membrane

how is glucose transported across epithelial cells (uphill)

lumen to intracellular fluid

how is glucose transported across epithelial cells (downhill)

intracellular to extracellular, active and passive transport

what drives ion flow through a channel

changes in voltage, chemical and electrical gradients

what determines whether an ion contributes to the membrane potential

• ionic gradients combined with membrane permeability to these ions via leak channels and Na+K+ATPase pump

what is the typical membrane potential and what. ion predominantly contributes to it

K+

-40 - -90mV

resting membrane potential

difference from zero

depolarization

move towards zero, decrease resting

repolarization

return to resting

hyper polarization

move away from zero

what ions contribute to membrane potential

Na+, K+, Cl-

how is insulin secretion regulated in Beta cells

change in Em elicits cellular response

• increase blood glucose

• increase intracellular glucose via GLUT

• increase ATP

• close K+ channels

• depolarization

• opens Ca2+ channels

• exocytosis of insulin

• decrease blood glucose

how do cells communicate in the body

chemical and electrical signals

endocrine

hormones - slow, sustained, diffuse

neural

NT- fast, focal

what is second messenger

intracellular signaling molecules released in response to extraceullar signaling molecules

• cAMP

• DAG

• IP3

• Ca2+

what are the four types of cell surface receptors and what are their pathways

• receptor channel

binding opens channel

what are the four types of cell surface receptors and what are their pathways

• G protein coupled receptor

binding activates G protein

what are the four types of cell surface receptors and what are their pathways

• receptor enzyme

binding activates receptor enzyme

what are the four types of cell surface receptors and what are their pathways

• integrin protein

binding alters cytoskeleton

what is the arachidonic acid cascade

action of phospholipase A2 acting on membrane phospholipids

what is nitric oxide

other cells signaling molecule

tonic control

up or down regulation by same input

antagonistic control

up or down regulation by independent inputs

CNS

brain and spinal cord, integrative center

PNS

sensory and efferent divisons, sensory input, motor output

basic components and functions of a neuron - dendrites

input

basic components and functions of a neuron - axon

conduction

basic components and functions of a neuron - terminal synapse

pre and post cleft ; transmission

anterograde and retrograde

fast

towards terminal; enzymes and cytoskeleton proteins

slow

CNS glia

• ependymal cells

• line ventricles

• stem cells

• astrocytes

PNS glia

• Schwann cells

• satellite cells

what determines resting membrane potential

• differences in intra/extra ion concentrations

• permeability

what happens to the membrane potential when the membrane becomes primarily permeable to one ion

resting membrane potential will equal the equilibrium potential for that ion

what are the relative gradients and the typical membrane potentials for Na+

+60

what are the relative gradients and the typical membrane potentials for K+

-90

what are the relative gradients and the typical membrane potentials for Cl-

-63

what are the relative gradients and the typical membrane potentials for Ca2+

too small

graded potentials

• passive

• amplitude reflects stimulus strength

• degrades with distance

• can be summed

• created by local current flow

action potentials

• active

• travel long distances without deradation

• can’t be sumed

• created by local voltage gated channels

rising phase

increase in Na

overshoot phase

increase and decrease of Na

increase in K

falling phase

increase and decrease K

decrease Na

undershoot

residual K

0 Na

what is the mechanism for the activation and inactivation of the voltage gated Na+ channels

depolarization opens activation gate and closes inactivation gate but different times

• activation opens first

• both reset with re polarization

what is the mechanism for the activation and inactivation of the voltage gated K+ channels

only has an activation gate that opens slower than Na+

how is the action potential conducted at the axon

graded potential at trigger zone (axon hillock and initial segment) and above threshold potential elicits action potential, depolarization from action potential causes local currents to flow, depolarizing adjacent membrane

what factors contribute to the speed of conduction

conduction velocity is proportional to axon diameter

what is saltatory conduction

myelin and Nodes of Ranvier, allowing action potentials to jump from Node to Node

acetylcholine

NT at neuromuscular junction and CNS

cleared by synaptic cleft

amines

synthesized from amino acid precursor

amin o acids GABA

brain inhibitory NT

amino acids Glycine

spinal cord inhibitory NT

amino acids Glutamate

excitatory NT most plentiful

general events of transmission

arrival of action potential

depolarization opens voltage gated Ca2+ channels

Ca2+ entry in terminal triggers exocytosis

NT release initiates neurotransmission]

NT diffuses across cleft and binds to postsynaptic receptor

acetylcholine transmission events

synthesized from choline and acetylcholine by acetylcholine transferase

broken down by acetylcholinesterase

choline re uptake and resynthesizes into acetylcholine

2 kinds of postsynaptic receptors involved in transmission

ICR directly

GPCR indirectly

spatial summation

graded potential from different inputs

temporal summation

graded potentials from same inputs

presynaptic inhibition

inhibition via neurotransmission (selective)

postsynaptic inhibition

inhibition via conduction (general)

where and how does the nervous system develop

originates as hollow tube and neural crest

• cells of tube become neurons and glia

• inside of hollow tube becomes ventricular system of brain and spinal cord

tube outside (tissue) becomes

The CNS