Nervous System

Question 1

Name FOUR phases of an Action Potential

Answer 1

• stimulus
• depolarising
• repolarising
• after-hyperpolarising

Question 2

Name the two refractory periods of an Action Potential in order of which occurs first.

Answer 2

• absolute

* relative

Question 3

Describe the action of the stimulus (in action potential).

Answer 3

mechanical/chemical stimulus activates ligand-gated channels which results in a depolarising graded potential (membrane reaches threshold -55mV)

Question 4

Describe the action of the depolarising phase (in action potential).

Answer 4

• voltage-gated Na+ channels open and Na+ rushes into cell

* raises membrane potential up to +30mV

Question 5

Describe the action of the repolarising phase (in action potential).

Answer 5

• voltage-gated Na+ channels inactivating
• voltage-gated K+ flows out
• membrane potential returns to resting potential (-70mV)

Question 6

Describe the action of the after-hyperpolarising phase (in action potential).

Answer 6

• voltage-gated K+ channels are open
• voltage-gated Na+ channels are in resting phase
• K+ continues to leave cell, membrane potential becomes more neg. -90mV.
• voltage-gated K+ channels close, membrane potential returns to resting state -70mV

Question 7

Name 5 neurotransmitters

Answer 7

• dopamine
• epinephrine
• norepinephrine
• serotonin
• Glutamate

Question 8

Name one associated function of DOPAMINE

Answer 8

pleasure and addiction

Question 9

Name one associated function of EPINEPHRINE

Answer 9

increases blood flow

Question 10

Name one associated function of NOREPINEPHRINE

Answer 10

regulates mood

Question 11

Name one associated function of SEROTONIN

Answer 11

appetite regulation

Question 12

Name one associated function of GLUTAMATE

Answer 12

learning and memory

Question 13

Do attachment to the following neurotransmitters result in excitory or inhibitory postsynaptic potential?

1. dopamine
2. epinephrine
3. norepinephrine
4. serotonin
5. glutamate

Answer 13

1. dopamine = E
2. epinephrine = E and I
3. norepinephrine = E and I
4. serotonin - I
5. glutamate = E

Question 14

Define graded potential

Answer 14

Small deviations from resting membrane potential of -70mV

Question 15

Describe both hyperpolarising and depolarising graded potential by describing the polarity of the membrane and the change in the charge.

Answer 15

• Hyperpolarising – inside cell becomes more positive

* Depolarising – inside cell becomes more negative

Question 16

List the 2 types of receptors that neurotransmitters attach to which produces either an EPSP or IPSP

Answer 16

• Ionotropic

* metabotropic

Question 17

Describe the criteria by which these receptors (ionotropic and metabotropic) are classified.

Answer 17

By whether the binding site and ion channel are components of the same protein

Question 18

Describe an IONOTROPIC receptor

Answer 18

binding site and ion channel on the same protein

eg Ligand-gated ion channels.

Question 19

Describe METABOTROPIC

Answer 19

binding site and ion channel on different proteins

eg AcH binds to binding site, activates the G-protein, activates ion channel.

Question 20

List the 2 classes of sensory modalities.

Answer 20

• special senses

* general senses

Question 21

Name and describe the 4 events that typically occur for a sensation to arise.

Answer 21

1. Stimulation of the sensory receptor
2. Transduction of the stimulus
3. Generation of the nerve impulse
4. integration of sensory input

Question 22

List 5 different types of sensory receptors according to the type of stimulus that is detected.

Answer 22

1. Mechanoreceptor
2. Thermoreceptor
3. Nocireceptor
4. Photoreceptor
5. Chemoreceptor

Question 23

What type of stimuli does the following receptor detect?

* Mechanoreceptor

Answer 23

touch, pressure, vibration, proprioception, hearing, equilibrium, monitor stretching of blood vessels and internal organs

Question 24

What type of stimuli does the following receptor detect?

* Thermoreceptor

Answer 24

changes in temp

Question 25

What type of stimuli does the following receptor detect? | * Nocireceptor

Answer 25

respond to painful stimuli resulting from physical or chemical damage to tissue

Question 26

What type of stimuli does the following receptor detect? | * Photoreceptor

Answer 26

detects light

Question 27

What type of stimuli does the following receptor detect? | * Chemoreceptor

Answer 27

detects chemicals in the mouth, nose and body fluids