Physiology

Question 1

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

Answer 1

Simple diffusion

Question 2

Net flux is zero

Answer 2

Diffusion equilibrium

Question 3

The magnitude of flux depends on what factors:

Answer 3

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

Question 4

Polar membranes dissolve (slowly/rapidly)

Answer 4

Slowly

Question 5

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

Answer 5

Rapidly, large

Question 6

Polar membranes need to use ___ for diffusion

Answer 6

Ion channels

Question 7

Humans are what % water?

Answer 7

60%

Question 8

Water is polar or non-polar?

Answer 8

Polar

Question 9

Hydrophilic versus hydrophobic

Answer 9

Hydrophilic loves water. Often are charged substances

Hydrophobic does not

Question 10

Charged substances (often hydrophilic)

Answer 10

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

Molecules: bicarbonate HCO3-, phosphate PO43-

Question 11

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

Answer 11

Hydrogen

Question 12

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

Answer 12

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

Question 13

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

Answer 13

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

Question 14

Fats are hydrophilic or hydrophobic? Why?

Answer 14

Hydrophobic, because they have no charge on the surface

Question 15

Examples of non-polar and hydrophobic substances

Answer 15

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

Question 16

A cell membrane consists of a ____

Answer 16

Phospholipid bilayer

Question 17

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

Answer 17

Polar, hydrophilic head

Fatty, hydrophobic tail

Question 18

What molecules can dissolve in the liquid bilayer and why?

Answer 18

O2, CO2, N2, benzene

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

Question 19

What molecules are repealed by the synthetic lipid bilayer and why?

Answer 19

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

Question 20

Osmosis

Answer 20

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

Question 21

Osmolarity

Answer 21

The total solute concentration of a solution

Question 22

Most body solutions have an osmolarity of ___

Answer 22

300 mOsm

Question 23

Electric potential

Answer 23

Voltage across the cell membrane

Question 24

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 ___

Answer 24

electrical potential=chemical potential

-96mV

Question 25

Types of channels

Answer 25

Voltage gated, ligand gated, mechanically gated, light gated

Question 26

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

Answer 26

Voltage gated

Question 27

Agonist in a ligand gated channel:

Answer 27

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

Question 28

Antagonist in a ligand gated channel:

Answer 28

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

Question 29

Channel are ___transport devices

Answer 29

Passive | This allows the downhill fluxes of ions

Question 30

What moves ions against their transportation gradients?

Answer 30

Pumps

Question 31

A molecule's permeability through a membrane is defined by___

Answer 31

It's tendency to dissolve in lipids

Question 32

Potassium equilibrium potential

Answer 32

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

Question 33

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

Answer 33

Action potentials

Question 34

How long (time wise) are action potentials?

Answer 34

1 ms

Question 35

Components of a neuron

Answer 35

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

Question 36

Stretch reflex

Answer 36

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

Question 37

Decreased stretch reflex is a sign of_____

Answer 37

demyelination

Question 38

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

Answer 38

Dorsal | Sensory

Question 39

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

Answer 39

Ventral | Motor

Question 40

Afferent

Answer 40

Dorsal, sensory

Question 41

Efferent

Answer 41

Ventral, motor

Question 42

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

Answer 42

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

Question 43

In the stretch reflex, the signal needs to be transmitted

Answer 43

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

Question 44

Advantages of chemical synapses

Answer 44

It is easier to build complex systems

Question 45

Excitatory chemical response

Answer 45

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

Question 46

Inhibitory chemical response

Answer 46

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

Question 47

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

Answer 47

Temporal summation

Question 48

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

Answer 48

15 | 1

Question 49

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

Answer 49

Decreasing

Question 50

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

Answer 50

Action potentials

Question 51

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

Answer 51

Axon hillock

Question 52

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

Answer 52

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

Question 53

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

Answer 53

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

Question 54

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

Answer 54

0.0001mM | 1mM

Question 55

Neuromuscular junction

Answer 55

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

Question 56

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

Answer 56

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

Question 57

ACh is broken down by _____ into ___ and ____.

Answer 57

ACh esterase (AChE) Choline Acetate

Question 58

AChE is located in _____.

Answer 58

postjunctional folds (AChR are on the surface)

Question 59

Mechanism of Botulinum toxin?

Answer 59

Cuts fusion proteins->vesicles are not released

Question 60

The goal of the neuron at the NMJ?

Answer 60

To depolarize muscle so that the muscle fires an action potential