Nervous System

Question 1

Central Nervous System

Answer 1

Brain and Spinal Cord

Processes and stores infromation

Question 2

Peripheral Nervous System

Answer 2

• All nerves outside the CNS
• Sensory, Motor
• Somatic System, Autonomic System
• Sympathetic, Parasympathetic

Question 3

Sensory Nerves

Answer 3

Conveys info from sensory receptors or nerve endings

Question 4

Motor Nerves

Answer 4

Stimulates voluntary and involuntary muscles

Somatic /Autonomic Systems

Question 5

Somatic System

Answer 5

• Controls the voluntary muscles
• MOtor neurons relase acetylcholine onto ACh receptors located on skeletal muscle
• Reflex action

Question 6

Autonomic System

Answer 6

Controls involuntary muscles(glands and smooth muscles)

Sympathetic/Parasympathetic

Question 7

Sympathetic

Answer 7

• Norepinephrine as primary neurotransmitter
• activates body for emergency situations
• Fight or flight response
• Increases heart and breathing rate
• Liver converts glycogen to glucose
• Bronchi of lungs dilate and icnrease gas exchange
• Adrenaline raises blood glucose levels

Question 8

Parasympathetic

Answer 8

• Acetylcholine as primary neurotransmitter
• rest-and-digest response
• deactivate or slow down
• vagus nerve is principle nerve
• Opposes the sympathetic system
• Calms the body
• Decreases heart/breathing rate
• Enhances digestion’

Question 9

Neuron

Answer 9

• Nerve Cell
• designed to transmit info in the form of electrochemical signals(action potentials)
• COmposed of Dendrites, axons, cell body, myelin Sheaths

Question 10

Dendrites

Answer 10

• Receive incoming messages from other cells as changes in membrane potential
• carry the electrical signal to the cell body

Question 11

Axon

Answer 11

• Only one for each neuron
• Transmits an impulse from the cell body to another cell
• wrapped in a myelin sheet that protects the axon and speeds the impulse

Question 12

Reflex Arc

Answer 12

• Simplest nerve response
• Inborn, automatic, protective
• ex/knee-jerk reflex
• Spinal cord is not involved
• Sensory, interneuron, motor neuron, muscle

Question 13

Membrane Potential

Answer 13

• A difference in electrical charge between the cytoplasm(negative charge) and extracellular fluid (positive)
• difference between -50mV to -100mV

Question 14

Polarized

Answer 14

• A polarized neuron is at rest or unstimulated (resting potential)
• membrane potential of -70mV
• Sodium-potassium pump acitively pumps ions out of the cell
• The larger the membrane potential, the stronger the stimulus must be to cause the nerve to fire
• Pos outside(sodium) ; neg inside(potassium)

Question 15

Action potential

Answer 15

• An impulse that can only be generated in the axon stimulated enough to overcome the threshold
• Sodium channels open and sodium flood into the cell
• Potassium channels open and potassium floods out of the cell
• Polarity of the membrane is reversed (pos inside; neg outside)
• Every action potential is the same size, but more frequency indiactes a larger stimulus

Question 16

Wave of depolarization

Answer 16

• Rapid movement ions when an impulse passes through an axon
• Sodium in; potassium out
• reverses the polarity of the membrane
• Membrane is less polarized, moving toward 0 potential

Question 17

Repolarization

Answer 17

Sodium-potassium pump restores the membrane to its orginal polarized condition

Question 18

Refractory Period

Answer 18

• Period of repolarization
• Neuron can’t respond to another stimulus
• ensures an impulse moves along an axon in 1 direction since the impulse can only move to a region where the membrane is polarized

Question 19

Myelin Sheet

Answer 19

Protects axon and speeds impulse

Question 20

What gives neurons an excitable membrane?

Answer 20

A voltage-gated sodium channel

Question 21

Threshold Potential

Answer 21

• The voltage at which the voltage-gated channels open

Question 22

THe larger the neuron….

Answer 22

The faster action potentials travel

Question 23

Nodes of Ranvier

Answer 23

Spaces between the myelin sheets that action potentials jumps from to another, bypassing myelin regions

Question 24

Saltatory conduction

Answer 24

Action potentials jumping from Nodes of Ranvier to other nodes

Question 25

Synapse/ Synaptic cleft

Answer 25

• Gap between neuron and target cell where neurotranmitters cross

Question 26

Neurotranmitter

Answer 26

• chemical signal
• Released by neuron when an action potential travels down an axon to reach the synaptic terminal
• diffuses across the gap between cells and bind to receptors on the target cell membrane

Question 27

Summation

Answer 27

• the means that a single neuron uses to process info from all neurons that form synapses with it and decide whether or not to initiate an action potential itself.
• determined by adding up the contributions to the membrane potential created by many synapses

Question 28

Neuromuscular junction

Answer 28

• A specialized synapse of motor neurons with skeletal muscle cells
• When reached by action potential, acetylcholien is released into the synaptic cleft and binds to postsynaptic receptors in the muscle cell
• receptors open sodium channels, depolrize msucle cell membrane, trigger muscle contraction

Question 29

Ways to turn off a synaptic neurotransmitter

Answer 29

1. Diffusion
2. Enzymes that degrade and inactive it (pesticides, nerve gas)
3. Take it up into cells at the synapse

Question 30

Vesicles

Answer 30

The cytoplams at the terminal branch contains many vesicles, each containing neurotransmitters

Question 31

What does deploarization of the presynaptic membrane cause?

Answer 31

• Ca++ ions rush into terminal branch
• stimulates the vesicles to fuse with the presynaptic membrane and release the neurotransmitter by exocytosis into the synapse
• sets up another action potential on teh adjacent cell

Question 32

Eye

Answer 32

Question 33

Ear

Answer 33

Question 34

Brain