The brain and CNS

Question 1

what 2 parts make up the CNS

Answer 1

brain and spinal cord

Question 2

what does CNS stand for

Answer 2

central nervous system

Question 3

what are the parts of the brain

Answer 3

cerebellum
medulla oblongata
cerebral; hemispheres

Question 4

what is the purpose of the cerebral hemispheres

Answer 4

control voluntary movement, senses and memory/learning

Question 5

what is the purpose of the medulla oblongata

Answer 5

do unconscious activities such as heart rate and breathing

Question 6

what is the purpose of the cerebellum

Answer 6

coordinates precise and smooth movement

Question 7

what are the 2 medical scans?

Answer 7

CT
PET

Question 8

what does a CT scan stand for

Answer 8

computerised tomography scans

Question 9

what does PET stand for

Answer 9

position emission tomography

Question 10

how does a CT scan work

Answer 10

a patient is given a radioactive tracer which allows for different parts of the brain to show up, a CT scan will be carried out taking X-rays of the scull from different angles
a computer puts all these images together to give a 3-dimensional image

Question 11

how does a PET scan work

Answer 11

the patient is given a radioactive form of glucose, which travels to the part of the body where rapid respiration is happening, the scanner detects the radioactivity and builds up images to show where the radioactive tracer is most concentrated

Question 12

what are 3 reasons why it is hard to create the brain

Answer 12

• they are well protected by the skull
• capillaries around the brain are not as leaky so getting medicines to the brain is - difficult
• neurons are specialised so cannot divide to replace damaged cells

Question 13

what are the 3 types of neurons?

Answer 13

sensory neurons
relay neurons
motor neurons

Question 14

what is the purpose of a sensory neuron

Answer 14

carry impulses to the CNS

Question 15

what is the purpose of relay neuron

Answer 15

carries impulses from one part of the CNS to another

Question 16

what is the purpose of motor neuron

Answer 16

carry impulses from CNS to their effector organs

Question 17

how does a sensory neuron work

Answer 17

the dendrites collect impulses from the receptor cells, and they travel along the dendron onto the axon and to the axon endings where the signal is passed to another neuron

Question 18

why is a relay neuron different from other neurons

Answer 18

they have a small dendron with lots of short axon endings surrounding the cell body to pass signals on in all directions

Question 19

what is the purpose of the myelin sheath

Answer 19

provides electrical insulation

Question 20

what do you call the gap between 2 neurons

Answer 20

synapse

Question 21

how does an electrical signal get across a synapse

Answer 21

1. electrical nerve reaches the axon endings
2. signal causes chemical neurotransmitters to be released
3. the neurotransmitters diffuse across the gap and fit in receptors creating a new electrical impulse in the next neuron

Question 22

what is a stimuli

Answer 22

a change in the environment

Question 23

what are the 4 things about reflex arcs

Answer 23

they are:
immediate
involuntary
innate
invariable

Question 24

why is the reflex arc important

Answer 24

it helps protect us from immediate arm

Question 25

why is the reflex arc so effective

Answer 25

the impulses had to go to the brain to be processed, there would be many synapses so the response would take longer. while in the reflex arc, the impulse only has to go to the spinal cord

Question 26

name the cycle for the reflex arc in steps

Answer 26

1. receptor detects stimuli
2. sensory neuron
3. relay neurons in the spinal cord
4. motor neuron
5. effector organs such as muscle