Ch16 Human Coordination

Question 1

Nervous system

Answer 1

Consist of central nervous system and peripheral nervous system

Question 2

Central nervous system

Answer 2

Consist of the brain and the spinal cord

Question 3

Peripheral nervous system

Answer 3

Consist of the cranial nerves (link receptor and effector of the head and neck to the brain) and the spinal nerves (link receptor and effector of other parts of the body to the spinal cord)

Question 4

The brain

Answer 4

Enclosed by the cranium. (Bone)
Protected by three meninges (membrane)
The inner and middle meninges is filled with cerebrospinal fluid.
-Provide nutrients and oxygen to the neurons and removing waste
-Act as shock absorber
-provide mechanical support to the brain

Question 5

Neurone

Answer 5

Dendrons, cell body, axons, myelin sheath

Question 6

Function of myelin sheath

Answer 6

-Insulate nerve fibre thus preventing the transmission of nerve impulses to the surroundings
-speed up the transmission of nerve impulses

Question 7

Transmission of nerve impulse across the synapses between neuron

Answer 7

Nerve impulse arrives at the synaptic knob at the axon terminal of a neuron
The nerve impulse stimulates the synaptic knob to release neurotransmitter
The neurotransmitter diffuses across the synaptic cleft
The neurotransmitter bind to specific protein receptors on the membrane of next neurone
This stimulates the dendron or cell body of the next neuron to generate a nerve impulse

Question 8

Reason why the nerve impulse cannot travel from one neuron to another

Answer 8

Because there is a narrow gap between the neuron

Question 9

Importance of synapses

Answer 9

-They ensure that nerve impulses travel in one direction only
-Allow a neuron to communicate with many other neurons

Question 10

Main parts of brain and their function

Answer 10

Cerebrum
-Produce sensation
-Site of intelligence
-Controls voluntary actions
Cerebellum
-Coordinates muscular movements
-maintain body balance
Medulla oblongata
-Controls involuntary actions (e.g. Breathing rate and heartbeat.)
A reflex centre for some reflex actions (cranial reflex)

Question 11

Cerebral cortex

Answer 11

The outer layer of the cerebrum

Question 12

Why is the cerebral cortex highly folded?

Answer 12

To increase the surface area to hold more neurons in a limited space

Question 13

Main areas in the cerebral cortex and their functions

Answer 13

Sensory area
-Receives nerve impulse from receptors to give sensations
Motor area
-transmits nerve impulses to effectors to produce voluntary responses
Association area
-integrates information from different sensory area and relate the information to past experience. Then the brain makes decision and send nerve impulses to motor areas to give a response. 

Question 14

Cerebrum and cerebellum distribution of grey matter and white matter

Answer 14

Outer layer is grey matter (contains cell bodies of neurons)
Inner layer is white matter (contains nerve fibre of neurons )

Question 15

Distribution of grey matter and white matter in the medulla oblongata and spinal cord

Answer 15

The inner layer is grey matter, consist of the cell bodies of neurons
The outer layer is white matter, consist of the nerve fibres of neurons

Question 16

Spinal cord and its function

Answer 16

At the centre of the grey matter is the central canal. It has cerebrospinal fluid.
It has vertebral column, protect from mechanical danger.

Question 17

Difference between reflex actions and voluntary actions

Answer 17

Nervous pathway: (R) involves the spinal cord or medulla oblongata, but not the cerebrum
(V) invloves the cerebrum
(R) A receptor is always involved
(V) may not involve any receptor if the action is initiated by the cerebrum directly

Nature of response: (R) automatic, inborn and sterotyped
(V) under conscious control, not inborn, and the same stimulus always results in a different response

Speed of response: (R) always fas
(V) maybe fast or slow, depending on the nervous pathway and nature of response