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Physiology > Physiology > Flashcards

Physiology Flashcards

1
Q

The movement of molecules from one location to another soley as a result of their random thermal motion

A

Simple diffusion

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2
Q

Net flux is zero

A

Diffusion equilibrium

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3
Q

The magnitude of flux depends on what factors:

A

Temperature
Mass of the molecule
Surface area
The medium through which the molecules are moving

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4
Q

Polar membranes dissolve (slowly/rapidly)

A

Slowly

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5
Q

Non-polar membranes dissolve (slowly/rapidly) across plasma membranes. They have (large/small) permeability coefficents.

A

Rapidly, large

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6
Q

Polar membranes need to use ___ for diffusion

A

Ion channels

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7
Q

Humans are what % water?

A

60%

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8
Q

Water is polar or non-polar?

A

Polar

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9
Q

Hydrophilic versus hydrophobic

A

Hydrophilic loves water. Often are charged substances

Hydrophobic does not

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10
Q

Charged substances (often hydrophilic)

A

Ions-K+, Na+, Cl-, H+ and Ca++

Molecules: bicarbonate HCO3-, phosphate PO43-

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11
Q

Electrostatic interactions between chloride ion and water is an example of a ____ bond

A

Hydrogen

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12
Q

Urea is polar or non-polar. Is it attracted to water?

A

Urea is polar. It is hydrophilic, therefore attracted to water

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13
Q

Glucose is polar or non-polar. Is it attracted to water?

A

Glucose is polar. It is hydrophilic, therefore attracted to water

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14
Q

Fats are hydrophilic or hydrophobic? Why?

A

Hydrophobic, because they have no charge on the surface

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15
Q

Examples of non-polar and hydrophobic substances

A

O2, CO2, N2, fats, oils, petrol/gasoline

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16
Q

A cell membrane consists of a ____

A

Phospholipid bilayer

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17
Q

A phospholipid molecule consists of a ___ head and a ___ tail.

A

Polar, hydrophilic head

Fatty, hydrophobic tail

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18
Q

What molecules can dissolve in the liquid bilayer and why?

A

O2, CO2, N2, benzene

They are small hydrophobic molecules. Therefore, they can dissolve in the lipid bilayer.

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19
Q

What molecules are repealed by the synthetic lipid bilayer and why?

A

H20, glycerol, ethanol=small uncharged polar molecules
amino acid, glucose, nucleotides=larger uncharged polar molecules
H+, Na+, HCO3+, K+, Ca2+, Cl-, Mg2+=ions

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20
Q

Osmosis

A

The process of the movement of water molecules from a solution in which free water concentration is higher to one in which free water concentration is lower

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21
Q

Osmolarity

A

The total solute concentration of a solution

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22
Q

Most body solutions have an osmolarity of ___

A

300 mOsm

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23
Q

Electric potential

A

Voltage across the cell membrane

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24
Q

In regards to potassium flow across the cell membrane, the cell reaches equilibrium when ___. At this point, the voltage across the cell membrane should be ___

A

electrical potential=chemical potential

-96mV

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25
Q

Types of channels

A

Voltage gated, ligand gated, mechanically gated, light gated

26
Q

K+ channels are an example of what type of channel?

A

Voltage gated

27
Q

Agonist in a ligand gated channel:

A

A chemical that binds to receptor ( for example, ACh) and activates the receptor to produce a biological response.

28
Q

Antagonist in a ligand gated channel:

A

A chemical that blocks the action of a normal ligand (for example, naloxone)

29
Q

Channel are ___transport devices

A

Passive

This allows the downhill fluxes of ions

30
Q

What moves ions against their transportation gradients?

A

Pumps

31
Q

A molecule’s permeability through a membrane is defined by___

A

It’s tendency to dissolve in lipids

32
Q

Potassium equilibrium potential

A

The voltage across cell membrane at which the net flow of potassium across the cell membrane is zero

33
Q

All neurons communicate with transient (1ms long) spikes called ____

A

Action potentials

34
Q

How long (time wise) are action potentials?

A

1 ms

35
Q

Components of a neuron

A

Dendrites-cell body-axon hillock-axon-axon terminal

36
Q

Stretch reflex

A

(knee-jerk reflex) - stretch a muscle and the reflex circuit leads to the contraction of the same muscle.

37
Q

Decreased stretch reflex is a sign of_____

A

demyelination

38
Q

In both the brain and the spine the back, or ____, is sensory/motor.

A

Dorsal

Sensory

39
Q

In both the brain and the spine, the front or____, is sensory/motor.

A

Ventral

Motor

40
Q

Afferent

A

Dorsal, sensory

41
Q

Efferent

A

Ventral, motor

42
Q

How is information encoded to determine what kind of motor response is needed?

A

Information is coded in frequency of action potentials (firing frequency): the higher the frequency the stronger quadriceps muscle would contract

43
Q

In the stretch reflex, the signal needs to be transmitted

A

from the stretch receptor axon terminal->the motor neuron->

from the motor neuron axon terminal->the muscle

44
Q

Advantages of chemical synapses

A

It is easier to build complex systems

45
Q

Excitatory chemical response

A

positive ions enter cell-> membrane voltage (Em) gets more positive = depolarization = Em gets closer to the threshold for Na+ channels

46
Q

Inhibitory chemical response

A

negative ions enter cell->Em gets more negative = hyperpolarization = Em gets farther away from the threshold for Na+ channels

47
Q

_____of Excitatory PostSynaptic Potentials (EPSPs) results in action potential in the postsynaptic cell

A

Temporal summation

48
Q

Postsynaptic potentials last longer than action potentials (___ms vs. ___ms).

A

15

1

49
Q

Since they are not amplified, postsynaptic potentials are (decreasing/increasing) in amplitude as one measures postsynaptic potentials away from a synapse:

A

Decreasing

50
Q

Postsynaptic potentials are graded potentials: the more excitatory ___ arrived—>the greater postsynaptic depolarization(as opposed to all-or-none APs)

A

Action potentials

51
Q

Usually one finds a number of inhibitory synapses right at the ____

A

Axon hillock

52
Q

Describe what happens to release the vesicles at the pre-synaptic neuron.

A

Action potential arrives at the axon terminal->voltage gated Ca2+ channels open and Ca2+ enters the axon terminal and opens the fusion pore->Ca2+ entry causes neurotransmitter containing synaptic vesicles to release their contents by exocytosis

53
Q

Describe what happens in the synapse and the post-synaptic neuron after the neurotransmitter containing vesicles are released by exocytosis at the axon terminal

A

Neurotransmitter (usually Ach) diffuses across the synaptic cleft and binds to ligand gated ion channels on the post synaptic membrane->ion channels permeable to K+ and Na+->influx of Na+ depolarizes the membrane, making it more likely to fire an action potential

54
Q

The Ca2+ concentration increases from ___ to ___in close vicinity to the vesicles after the Ca2+ ion channels are opened

A

0.0001mM

1mM

55
Q

Neuromuscular junction

A

a highly specialized synapse between a motor neuron nerve terminal and its muscle fiber that are responsible for converting electrical impulses generated by the motor neuron into electrical activity in the muscle fibers

56
Q

What would happen if ACh is allowed to hang around ACh receptor for too long?

A

Muscle will stay contracted and control over muscle will be lost.

57
Q

ACh is broken down by _____ into ___ and ____.

A

ACh esterase (AChE)
Choline
Acetate

58
Q

AChE is located in _____.

A

postjunctional folds (AChR are on the surface)

59
Q

Mechanism of Botulinum toxin?

A

Cuts fusion proteins->vesicles are not released

60
Q

The goal of the neuron at the NMJ?

A

To depolarize muscle so that the muscle fires an action potential

Physiology (8 decks)

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