B3.1 The Nervous System

Question 1

CNS

Answer 1

brain and spinal chord

Question 2

PNS

Answer 2

where stimulus is detected and response is done

Question 3

Sensory Neurone

Answer 3

carry impulses from receptor cells to CNS

Question 4

Motor Neurone

Answer 4

carry impulses from CNS to effectors

Question 5

Relay Neurone

Answer 5

only found in CNS

connects sensory neurones to motor neurones

Question 6

Nervous Reaction Flow DIagram

Answer 6

stimulus->receptor cells->sensory neurones-> spinal chord->brain->spinal chord->motor neurones->effector->response
0.7 seconds

Question 7

Reflex Arc

Answer 7

Skips out on brain to make response time (0.7s -> 0.2s) quicker.
Reflexes are for involuntary actions (closing eye at bright light)

Question 8

Reflex Arc Flow Diagram

Answer 8

stimulus->receptor cells->sensory neurones->spinal chord->motor neurones->effector->response
0.2 seconds

Question 9

Causes of nervous system damage

Answer 9

injury
disease
genetic conditions
toxic substances

Question 10

Damaged PNS

Answer 10

inability to detect pain
numbness
loss of coordination
-can regenerate

Question 11

Damaged CNS

Answer 11

loss of control over body systems
partial/complete paralysis
memory loss/processing difficulties
-permanent damage unless surgery is done (mostly unfixable)

Question 12

Why is the CNS hard to treat

Answer 12

Spinal chord has many nerve pairs (31) packed into a tight space (1.5cm) so it is hard to repair a single pair
MRI or CT scans are needed to diagnose brain damage

Question 13

Treatments for Brain Damage

Answer 13

Radiotherapy + Chemotherapy - brain tumours
Surgery - to remove bad brain tissue
Deep Brain Stimulation - inserting electrode to stimulate brain activity