Nervous System 2.0

Question 1

What does the nervous system carry?

Answer 1

Electrical messages

Question 2

What does the endocrine system carry?

Answer 2

Chemical messages

Question 3

What is an adaptation of the nervous system?

Answer 3

It is divided into two parts, CNS & PNS.

Question 4

What is the Central Nervous System (CNS) composed of?

Answer 4

The brain and spinal cord.

Question 5

What is the Peripheral Nervous System (PNS) composed of?

Answer 5

Nerves in all other body parts that carry messages to and from the CNS.

Question 6

What is a neuron?

Answer 6

A nerve cell that is specialised to carry impulses in the body.

Question 7

What are the 3 types of neurons in the PNS?

Answer 7

Sensory neuron, Interneuron, motor neuron.

Question 8

What do sensory neurons do?

Answer 8

Carry impulses towards the CNS.

Question 9

What do motor neurons do?

Answer 9

Carry impulses away from the CNS.

Question 10

What is the function of an interneuron?

Answer 10

Connects motor & sensory neurons.

Question 11

Do interneurons have a myelin sheath?

Answer 11

No

Question 12

What is an effector?

Answer 12

Organ or tissue that carries out an action in response to a signal from the nervous system.

Question 13

Why are sensory and motor neurons white?

Answer 13

Due to the presence of the myelin sheath.

Question 14

What are nerves made up of?

Answer 14

A bundle of many axons.

Question 15

Why won’t 2 electrical signals collide?

Answer 15

As sensory & motor neurons carry signals in one direction.

Question 16

What is the threshold?

Answer 16

Minimum stimulus required to carry an impulse.

Question 17

What is the all or nothing law?

Answer 17

If the threshold is not reached, no impulse is carried.

Question 18

How is an impulse conducted?

Answer 18

Ions

Question 19

What is the refractory period?

Answer 19

The short timespan after a neuron has carried an impulse during which a stimulus fails to carry a response.

Question 20

What does the speed of an impulse depend on?

Answer 20

Presence & abundance of myelin sheath.

Question 21

What is a synapse?

Answer 21

Region where 2 neurons come in close contact.

Question 22

What is the synaptic cleft?

Answer 22

Tiny gap between the 2 neurons at the synapse.

Question 23

What is the function of neurotransmitter chemicals?

Answer 23

Controls impulse direction.

EG: Dopamine

Question 24

What are the main bone structures associated with the CNS?

Answer 24

The skull and spine - to provide protection.

Question 25

What encloses the brain & skull?

Answer 25

3 membranes called meninges.

Question 26

What infection is associated with the meninges?

Answer 26

Meningitis

Question 27

What is the difference between white matter and grey matter?

Answer 27

White matter has myelin sheath & grey has none.

Question 28

Where is cerebrospinal fluid located?

Answer 28

Between the two inner meninges.

Question 29

What is the function of cerebrospinal fluid?

Answer 29

Helps absorb the impact that may occur, hence protects structures.

Question 30

What is the cerebrum composed of?

Answer 30

Left & right hemispheres. The right side controls the left & vice versa.

Question 31

What are the 4 parts of the cerebrum?

Answer 31

Frontal lobe, Temporal lobe, Parietal lobe, Occipital lobe.

Question 32

What are the functions of the cerebrum?

Answer 32

Language, Speech, Touch, Hearing.

Question 33

Where is the cerebellum located?

Answer 33

At the back of the head, underneath the occipital lobe of the cerebrum.

Question 34

What is the function of the cerebellum?

Answer 34

Responsible for the control & coordination of movements, particularly fine-tuning of movements.

Question 35

What does the medulla oblongata control?

Answer 35

Non-voluntary actions in the body, e.g., BP, breathing & swallowing.

Question 36

What is a reflex action?

Answer 36

An automatic, unconscious or involuntary response to a stimulus.

Question 37

What are examples of reflex actions?

Answer 37

Knee jerking, Pulling hand away from hot object, Blinking.

Question 38

Why carry out reflex actions?

Answer 38

Protection, Faster action, if necessary.

Question 39

What is the hypothalamus?

Answer 39

Links brain & endocrine, secretes neurohormones - controls pituitary gland, controls Body Temp.

Question 40

What is the function of the spinal cord?

Answer 40

Sends messages to & from brain, active role in reflex actions.

Question 41

What is the movement of messages in the spinal cord?

Answer 41

A sensory neuron enters the dorsal root, reaches the synapse, neurotransmitter chemicals pass across the synaptic cleft to an interneuron, then to a motor neuron, and exits through the ventral root.

Question 42

What does white matter contain?

Answer 42

Sensory & motor neurons & myelin sheath.

Question 43

What does grey matter contain?

Answer 43

Only interneurons, cell bodies & dendrites but has no myelin sheath.

Question 44

What is the central canal?

Answer 44

The centre of grey matter - filled with cerebrospinal fluid.

Question 45

What is the dorsal root?

Answer 45

Where sensory neurons enter the spinal cord.

Question 46

What is the ventral root?

Answer 46

Where motor neurons exit the spinal cord.

Question 47

What is the dorsal root ganglion?

Answer 47

Contains cell bodies of sensory neurons.

Question 48

What is the method of reflex action when placing hand on a hot object?

Answer 48

Finger receptors detect hot object, impulse travels along sensory neuron to spinal cord, splits at spinal cord, half to interneuron, half to brain, then impulse travels out through motor neuron to muscle for response.

Question 49

What is a disorder of the nervous system?

Answer 49

Parkinson's disease. ## Footnote Cause: body fails to produce dopamine. Symptoms: Difficulty walking. Prevention: No known cause, so no known cure. Treatment: Physiotherapy.

Question 50

What is the function of dendrites?

Answer 50

Carry impulses toward the cell body.

Question 51

What is the function of the axon?

Answer 51

Carries impulses away from the cell body.

Question 52

What is the function of the cell body?

Answer 52

Receives impulses and produces neurotransmitter chemicals.

Question 53

What is the function of the myelin sheath?

Answer 53

Speeds up impulses.

Question 54

What are Schwann cells?

Answer 54

Type of cell that forms myelin sheath.

Question 55

What are axon terminals?

Answer 55

Found at the end of axons.

Question 56

What are neurotransmitter swellings?

Answer 56

Found in axon terminals. Produce neurotransmitter chemicals at the synapse.

Question 57

How is a nerve impulse transmitted across a synaptic cleft?

Answer 57

Impulse arrives as an electrical impulse, changes to chemicals at the synaptic cleft, diffuses across, and is received by the next neuron to change back to an electrical impulse.