Physiology: Cellular Physiology (Exam I)

Front 1

Which systems are pivotal in the maintenance of proper internal mileau?

Back 1

respiratory system: gas exchange and pH
digestive system: nutrient absorption
urinary system: ionic composition of plasma and excretion

Front 2

What is the boundary between the plasma and interstitium?

Back 2

capillary wall

Front 3

What is the boundary between the interstitium and intracellular environment?

Back 3

the cell membrane

Front 4

ECF is primarily composed of:

Back 4

Na, Cl and bicarbonate salts

Front 5

The ICF is primarily:

Back 5

K and organic anions

Front 6

Large proteins are generally excluded from the ____________.

Back 6

interstitial component of the ECF

Front 7

Intercellular clefts in capillary walls provide exchange of only small molecules such as ______ and lipid soluble molecules such as ______.

Back 7

small -water, sodium, urea, glucose, etc.

lipid soluble -oxygen, CO2

Front 8

The cellular membrane blocks movement of all ____________ molecules including ______.

Back 8

charged; ions

Front 9

Lipid bilayer membrane of cells filters all but _________ _______ molecules ___, ____, and ______.

Back 9

lipid soluble: O2, CO2, and H20

Front 10

Clefts between endothelial cells filter cells and proteins from entering _______

Back 10

interstitial (ECF) space

Front 11

How are polar, charged ions, glucose, etc. transported across cell membranes?

Back 11

specialized channels and transporters

Front 12

What are the four main transport mechanisms?

Back 12

1. bulk transport
2. diffusion
3. osmosis
4. carrier transport systems _

Front 13

clefts between endothelial cells filter cells and proteins from entering the _____________ ____

Back 13

interstitial space

Front 14

lipid bilayer membrane of cells filters all but ...

Back 14

lipid-soluble molecules (CO2, O2) and water

Front 15

Can glucose diffuse across the cell membrane? through capillary wall?

Back 15

capillary wall - si
cell membrane - no

Front 16

For bulk transport of solute and solvent flow is equal to:

Back 16

the change in the pressure at two points/ resistance

Front 17

What are two examples of bulk transport?

Back 17

1. circulation
2. pulmonary airflow

Front 18

The amount of material crossing a surface in a unit of time is known as a _______

Back 18

flux

Front 19

Which is dependent on concentration, flux or permeability?

Back 19

flux is dependent on concentration while permeability is not

Front 20

Voltages are created by ...

Back 20

diffusion of charged molecules

Front 21

diffusion of electrolytes in solution leads to the production of ___________ ___________

Back 21

diffusion potentials

Front 22

What are the common features of ion channels?

Back 22

1. aqueous pore
2. sensor for opening: voltage, ligand, second msg, stress, etc.
3. a "gate"
4. a selectivity filter -only certain ions pass

Front 23

movement through ion channels does not require _______ , so the diffusion is said to be ___________.

Back 23

ATP; passive

Front 24

What is osmolarity?

Back 24

total solute concentration of a solution

Front 25

What is tonicity?

Back 25

refers to whether or not a cell will shrink depending on concentration difference of NON-PERMEABLE osmolites/NON-PENETRATING solutes only

Front 26

In simple diffusion, flux rate is limited only by the _____________ ___________.

Back 26

concentration gradient

Front 27

In carrier-mediated transport, the number of carriers places an __________ ________ on the _________ ________.

Back 27

upper limit; flux rate

Front 28

____________ ______________ is the separation of charge that has the potential to do work.

Back 28

electrical potential (E)

Front 29

Electrical potential increased under what two circumstances?

Back 29

1. with increasing number of charges
2. the closer the separated charges get to each other

Front 30

_________ is the movement of electrical charges

Back 30

current

Front 31

flow of electrical charges (current) depends upon what?

Back 31

the potential difference between charges (voltage) and the type of material through which the charge must move (resistance)

Front 32

What is Ohm's law?

Back 32

current = electrical potential / resistance

Front 33

What does Poiselle's Law state?

Back 33

liquid flow = pressure/ resistance

analogous to Ohms law: electric current = electric potential / resistance

Front 34

What does the Nernst equation describe?

Back 34

The membrane potential a single ion would produce if the membrane were permeable only to that ion

Front 35

What determines how much influence an ions' nernst potential has on voltage?

Back 35

relative permeabilities

Front 36

What is the effect on resting membrane potential following an increase in permeability of Calcium? A decrease in potassium permeability?

Back 36

Calcium enters cell, potassium leaves cell -both depolarizing effect (make the membrane potential more positive)

Front 37

Entry of Ca or Na _________ cell and the membrane potential becomes more ____________.

Back 37

depolarizes; positive

Front 38

Entry of Cl __________ cell and the membrane potential becomes more __________.

Back 38

hyperpolarizes; negative

Front 39

Retention/entry of K into cell ___________ the cell and the resting membrane potential becomes more _____________

Back 39

hyperpolarizes; negative

Front 40

When K leaves the cell (with an increase in membrane permeability), the resting membrane potential becomes more ____________ and the cell is ___________.

Back 40

negative; hyperpolarizes

Front 41

What are the major resting currents in neuron? striated muscle? smooth muscle?

Back 41

neuron - K (-80 mv)
striated - K and Cl (-80 mv)
smooth - K (-50 mv)

Front 42

In dendrites and cell bodies of neurons ________ gated ion channels are abundant

Back 42

ligand

Front 43

In axon (and axon hillock) ________ gated ion channels are abundant

Back 43

voltage

Front 44

What are the common EPSP ligand gated ion channels?

Back 44

Acetylcholine and glutamate receptors (sodium and calcium)

Front 45

What are the common IPSP ligand gated ion channels?

Back 45

GABA and glycine - chloride

Front 46

The depolarization caused by the opening of ligand-gated channels causes a ___________ depolarization (EPSP) or hyperpolarization (IPSP).

Back 46

graded (transient)

Front 47

Graded potentials lose strength as they propagate due to ___________ ______ and ___________ ____________.

Back 47

1. current leak
2. cytoplasmic resistance

Front 48

Graded potentials move by ___________ _____________ (passively diffuse).

Back 48

electrotonic decay

Front 49

The greater the _________ ________ (inward current), the further a graded potential travels.

Back 49

voltage change

Front 50

Multiple, rapid EPSPs from the same synapse are additive if the time between each is short.

Back 50

temporal summation

Front 51

2 different synapses activated at the same time produce greater depolarization than at different times.

Back 51

spatial summation

Front 52

What is the major difference between CNS neurons and synapses at NMJs?

Back 52

a single EPSP at a neuron/muscle synapse is sufficient to cause an AP while CNS neurons require input from many converging synapses to evoke an AP

Front 53

The inactivation sodium gates can only be removed by ______________ the membrane.

Back 53

repolarizing

Front 54

What do sodium channels rely on in order to generate additional action potentials?

Back 54

repolarization by potassium channels (to "reset" both activation and inactivation gates in the sodium channel)

Front 55

unmyelinated axons have high concentrations of ____________ throughout their axons.

Back 55

voltage dependent sodium and potassium channels

Front 56

Why do AP flow unidirectionally?

Back 56

inactivation / the refractory period

Front 57

local anesthetics block ________________

Back 57

sodium channels

Front 58

how does conduction through a sensory neuron differ from the norm?

Back 58

1. sensory nerve endings take the place of the dendrites to cause depolarization / initiate AP
2. nerve endings connect directly to the axon without an intervening soma

Front 59

What are the two ways that conduction is stopped?

Back 59

1. blocking voltage-gated sodium channels
2. demyelination diseases (MS -autoimmune disease in which the autoimmune response is to myelin)

Front 60

Pacemaker cells in the heart do not have an EPSP, but have self-generating action potentials accomplished by what?

Back 60

hyperpolarizing activated cation (potassium) channels which brings the voltage to threshold for voltage-dependent calcium channels

Front 61

SA node action potentials are characterized by what?

Back 61

1. slow, Ca2+ dependent upstroke (no Na channels!)
2. K+ dependent repolarization

Front 62

What are the steps in neurotransmission?

Back 62

1. action potential reaches axon terminal and depolarization causes voltage-gated calcium channels to open
2. calcium enters, causes exocytosis of synaptic vesicle contents (NT) into the synaptic cleft
3. NT diffuses across synaptic cleft and binds with receptors on postsynaptic cell

Front 63

What are the steps in the termination of postsynaptic excitation?

Back 63

1. postsynaptic receptors desensitize
2. NT is enzymatically degraded (inactivated) in the synaptic cleft
3. NT diffuses away from synapse
4. NT is taken up by NT re-uptake transporters (serotonin, dopamine , glutamate)

Front 64

What is the mechanism of neurotoxic tetrodotoxin from Fugu?

Back 64

the blockage of voltage-dependent sodium channels

Front 65

What is the mechanism of neurotoxic botulinum toxin?

Back 65

prevents neurotransmission by cleaving Synaptotagmin

Front 66

What is the mechanism of neurotoxic Saxitoxin (red tide) shellfish poisoning?

Back 66

the blockage of voltage-dependent sodium channels

Front 67

What are three ways neurotransmission is prevented?

Back 67

1. botulinum toxin
2. lambert eaton syndrome -autoimmune to presynaptic calcium channels
3. myesthenia gravis -autoimmune against Ach receptors

Front 68

autoimmune disease against Ach receptors that prevents neurotransmission

Back 68

mysethenia gravis

Front 69

autoimmune disease against myelin that stops conduction of AP?

Back 69

multiple sclerosis

Front 70

autoimmune disease against presynaptic calcium channels that prevents neurotransmission

Back 70

lambert eaton syndrome

Front 71

Presynaptic depression (of glutamate autoreceptors) is characterized by ______ NT release which activates ________ receptors that _________ subsequent neurotransmitter release.

Back 71

high; mGluR; depress

Front 72

receptors that alter ion channel function are called __________

Back 72

ionotropic

Front 73

What are the two types of postsynaptic glutamate-gated channels involved in LTP?

Back 73

1. non-NMDA (conduct only Na; voltage INDEPENDENT)
2. NMDA (conduct Na and Ca; requires STRONG depolarization for removal of Mg which occludes the voltage-gated channel)

Front 74

____________ influx through _______ receptors is key in long term potentiation.

Back 74

Calcium; NMDA

Front 75

What are the steps in the early and late phases of postsynaptic long term potentiation?

Back 75

early:
1. glutamate binds to both non-NMDA and NMDA receptors
2. sodium enters through non-NMDA channels and depolarizes cell
3. depolarization ejects the Mg blocking the NMDA channel and calcium enters the postsynaptic cell
4. calcium-dependent kinases (calcium/calmodulin kinase) phosphorylate non-NMDA glutamate receptors, enhancing their sensitivity to glutamate (resulting increased glutamate release)

late:
5. calcium/calmodulin kinase also activate cAMP signaling pathway to the nucleus to produce new synapses via transcription factors such as CREB

Front 76

What effect does binding of metabotropic receptors have? What does binding of metabotropic receptors involve?

Back 76

causes changes in metabolites that affect signaling or excitability; involves second-messenger signaling pathways

Front 77

parasympathetic nervous system involves Ach binding to _____________ receptors, which are a type of ____________ receptor.

Back 77

muscarinic acetylcholine; metabotropic

Front 78

Which division of the PNS uses metabotropic receptors?

Back 78

ANS

Front 79

What are some advantages of metabotropic receptor signaling?

Back 79

-one NT can evoke different responses in different cells because their receptors are coupled to different signaling cascades
-allows for amplification of signals

Front 80

What is "contraction time?"

Back 80

time for SR Ca-ATPase to pump calcium back in SR

Front 81

The DHP receptor complex of skeletal muscle includes a voltage-dependent calcium channel that serves to sense depolarization and

Back 81

physically/mechanically moves the RyR receptor in order to release Ca form the SR