Biology Ch. 4

Question 1

What is the equilibrium potential of potassium

Answer 1

-90mV

Question 2

The resting potential of a cell is similar to the potential of (Na+/K+) because ____

Answer 2

K+. because the cell is slightly more permeable to potassium

Question 3

Explain the movement of ions with the sodium potassium pump

Answer 3

Potassium in, sodium out

Question 4

Describe the events of an incoming stimulus on the membrane potential

Answer 4

1) stimulus causes graded potential and ligand gated cation channels open
2) graded potential reaches threshold and voltage gated sodium channels open to allow sodium in
3) membrane is depolarized; voltage gated potassium channels start opening and voltage gated sodium channels close
4) repolarization; voltage gates sodium channels closed and potassium channels open so potassium leaves cell
5) voltage gated potassium channels closing
6) hyperpolarization; all potassium leak channels are open and some voltage gated potassium channels are open
7) all voltage gated potassium channels are closed

Question 5

During hyperpolarization, all ___ channels are open and some ___ channels are open and some are closed

Answer 5

K+ leak channels are open, some voltage gated potassium channels are open and some closed

Question 6

Define temporal summation

Answer 6

Multiple signals are integrated during a brief time period

Question 7

Define spatial summation

Answer 7

additive effects are based on number and location of incoming signals (i.e. many firing on the hillock versus many [or few] signals firing on dendrites)

Question 8

Define absolute refractory period

Answer 8

no amount of stimulation can cause an action potential

Question 9

Define relative refractory period

Answer 9

must be greater than normal stimulation to cause action potential as membrane is starting from potential that is more negative than its resting value

Question 10

How does axon length impact action potential speed?

Answer 10

Longer axon = higher resistance and slower conduction

Question 11

How does cross section impact action potential speed?

Answer 11

Greater cross section = decreased resistance and faster propagation

Question 12

Action potential speed is determined by both ___ and ___, though ___ has a greater effect

Answer 12

cross section and length, cross section has greater effect

Question 13

Define effector

Answer 13

A postsynaptic cell on a gland or muscle that receives neuron signals

Question 14

When an action potential reaches the nerve terminal, voltage-gated ___ channels open, allowing ___ to flow into the cell

Answer 14

Calcium

Question 15

What ways are neurotransmitters regulated at the synaptic cleft?

Answer 15

1) broken down by enzymatic reactions
2) brought back via reuptake
3) diffuse out of synaptic cleft

Question 16

What neurotransmitter(s) are regulated by being broken down by enzymatic reactions? what are they broken down by?

Answer 16

Ach by AchE

Question 17

What neurotransmitter(s) are regulated by being brought back into the synaptic cleft via reuptake?

Answer 17

Serotonin by 5-HT
Dopamine
NE

Question 18

What neurotransmitter(s) are regulated by diffusing out of the synaptic cleft?

Answer 18

NO

Question 19

Define supraspinal circuits

Answer 19

reflexes that require input from the brain or brain stem

Question 20

List the 4 divisions of the spinal cord

Answer 20

1) cervical
2) thoracic
3) lumbar
4) sacral

Question 21

____ protects the spinal cord and transmits nerves between adjacent vertebrae

Answer 21

Vertebral column

Question 22

The dorsal horn/root receives ___ information

Answer 22

sensory

Question 23

the ventral horn/root receives ___ information

Answer 23

motor

Question 24

Axons of motor and sensory neurons are found in the ____

Answer 24

spinal cord

Question 25

Sensory cell bodies are found in the ____ of the spinal cord

Answer 25

dorsal root ganglia

Question 26

Sensory neurons enter the spinal cord ____

Answer 26

dorsally

Question 27

Motor neurons exit the spinal cord _____

Answer 27

ventrally

Question 28

How to motor neurons go from the spinal cord to the muscle?

Answer 28

Directly, without synapsing

Question 29

The peripheral component of the autonomic nervous system has _ neurons to transmit information

Answer 29

2

Question 30

List the two neurons of the ANS

Answer 30

1) preganglionic

2) postganglionic

Question 31

The soma of preganglionic neurons of the ANS is located ____

Answer 31

in the CNS

Question 32

The axon of the preganglionic neurons of the ANS is located ____

Answer 32

in the PNS

Question 33

Preganglionic neurons of the ANS snapes onto ____

Answer 33

the cell bodies of post ganglionic neurons

Question 34

Postganglionic neurons of the ANS stimulate ___ to release ___ for the ___ system

Answer 34

Postganglionic neurons of the ANS stimulate target tissue to release NE for the sympathetic nervous system

Question 35

List the two types of reflex arcs

Answer 35

1) monosynaptic

2) polysynaptic

Question 36

Define monosynaptic reflex arc

Answer 36

single synapse between sensory neuron that receives stimulus and motor neuron that responds

Question 37

Define polysynaptic reflex arc

Answer 37

at least 1 interneuron between sensory and motor neurons; Interneurons in spinal cord provide connections from incoming sensory information to motor neurons of supporting limb

Question 38

The knee-jerk (patellar) reflex goes along the _____ reflex arc

Answer 38

monosynaptic

Question 39

The withdrawal reflex uses a ____ reflex arc

Answer 39

polysynaptic