4.7 - The Nervous System

Question 1

What is the central nervous systems and what parts does it consist of?

Answer 1

• the brain
• the spinal cord > its the central bundle of nerves running down the body
• there is a highly concentrated area of neurons at the top of the spinal cord

Question 2

What is the peripheral nervous sytem?
What 2 parts does it seperate into?

Answer 2

• it is nerves that branch off from the central nervous system
• sperates into the autonomic and somatic nervous system

Question 3

What is the somatic nervous sytem?
What 2 parts does it seperate into?

Answer 3

• nerves that regulate activities under voluntary control (like muscules)
• it splits into spinal and cranial nerves

Question 4

What are sensory (cranial) nerves?

Answer 4

Afferent (towards) nerves that bring info towards the central nervous system

Question 5

What are motor (spinal) nerves?

Answer 5

Efferent (away) nerves that send info out of the central nervous system. It iniates appropriate responses/movement

Question 6

What is the autonomic nervous sytem?
What 2 parts does it seperate into?

Answer 6

• nerves that regulate activities which occur involuntarily without thought (controls organs)
• splits into sympathetic and parasympathetic nervous system

Question 7

What is the sypmathetic nervous sytem?
What part does it seperate into?

Answer 7

• uses to activate systems especially as part of fight or flight
• preps body for stress, increase energy consumption
• splits into spinal nerves only

Question 8

What is the parasypmathetic nervous sytem?
What parts does it seperate into?

Answer 8

• used to deactivate systems and bring them to rest
• “rest and digest”
• restore to normal from stress, preserving energy
• seperates in spinal and cranial nerves

Question 9

What is a neuron?

Answer 9

Specialized cells that transmits chemical and electrical signals

Question 10

What are dendrites?

Answer 10

• convey signals
• incoming towards cell body
• short but many
• extensively branched (increased surface are)

Question 11

What are axons?

Answer 11

• they send messages away from the cell body
• larger in size
• only one insultated by myelin & schwann cells

Question 12

What are myelin & schwann cells?

Answer 12

• myelin insulate the axon
• schwann cells are within the myelin

Question 13

There are small gaps in myelin codes. What is it called

Answer 13

the Nodes of Raniver

Question 14

What is a reflex arc?

Answer 14

• a stimulus will by-pass the brain, going to the spinal cord, then back to the point of the stimulus
• stimulus-> sensory neuron-> interneurons-> motor neurons-> effector

Question 15

What is the purpose of the spinal cord?

Answer 15

To carry impusles between the brain and the rest of the body (PNS)

Question 16

What are 2 reasons why the spinal cord is made of multiple pieces and not one solid piece?

Answer 16

• spinal nerves come out between each vertabrea
• mobility: if it was one solid piece, we couldn’t perform every day tasks properly ie. bending down, stretching, and anything that involves the movement of our backs