The Nervous System

Question 1

What does the nervous system do?

Answer 1

The central nervous system (CNS) coordinates a response
It is where all the information from the sense organs is sent, and where reflected and actions are coordinated

Question 2

What does the CNS consist of

Answer 2

It consists of the brain and spinal chord

Question 3

What are the 3 main parts of a nervous response

Answer 3

Stimulus - a chance is detected in the environment
Sensory receptors - group of cells that detect the sensory change
Effectors - muscle glands that respond to a nervous system,

Question 4

What is the structure of a motor neurone

Answer 4

• dendrites
• cell body at the end of axon terminal
• axon terminal made up of Schwann cells with axon running through it

Question 5

What is the structure of a sensory neurone

Answer 5

Dendrites at the end
Cell body located in the axon terminal, between the Schwann cells

Question 6

What do sensory receptors do

Answer 6

They are a group of cells that detect the sensory change

Question 7

What is the function of effectors

Answer 7

They are muscle glands that work together to respond to a nervous system

Question 8

What do receptor cells do

Answer 8

They change the stimulus form the surrounding to electrical impulses, different receptors detect different stimulus

Question 9

Function of sensory neurones

Answer 9

Carry electrical impulses from receptor cells to the CNS

Question 10

What do relay neurones do

Answer 10

Carey electrical impulses from sensory neurones to the motor neurones

Question 11

What does the motor neurone do

Answer 11

Carries electrical impulses from the CNS to the effectors

Question 12

How does the impulse travel through a neurone

Answer 12

The impulse goes from the dendrites to to the axon

Question 13

What is a reflex action

Answer 13

A reflex action is an automatic (involuntary) reaction, which occur without thinking

Question 14

How does a reflex action occur

Answer 14

Stimulus -> receptor cells -> sensory neurone -> spinal chord -> motor neurone -> effector -> response

Question 15

How does a regular reaction occur

Answer 15

Stimulus -> receptor cells -> sensory neurone -> spinal chord -> brain -> spinal chord -> motor neurone -> effector -> response

Question 16

Why is a reflex action faster than a voluntary action

Answer 16

A reflex action is coordinated in the spinal chord, meaning that the impulse doesn’t not need to travel to the brain, meaning it is able to be carried out much faster than a voluntary action

Question 17

What do the receptor cells do

Answer 17

They change the stimulus (change in surrounding) into electrical impulses. Different receptors detect different stimuli

Question 18

How is an impulse carried from one neurone to another

Answer 18

1) The impulse travels along the axon and is sped up by the myelin sheath.

2) When it reaches the end of the axon, the impulse arrives at a place called the axon terminal, and the gap between this neuron and the next is called the synaptic cleft.

3) The neurons never touch and instead communicate by releasing chemicals through the synaptic cleft.

4) At the axon terminal, the arrival of the impulse causes special structures called synaptic vesicles to release chemicals called neurotransmitters.

5) These neurotransmitters diffuse across the synaptic cleft to start the impulse in the next neuron

Question 19

How do relay neurones carry implisees from the sensory neurone to the motor neurone

Answer 19

1) Stimulus Detection: A sensory neuron detects a stimulus (like heat or light) and generates an electrical signal called an action potential.

2) Transmission to CNS: The sensory neuron transmits this action potential along its axon to the central nervous system (CNS), which includes the brain and spinal cord.

3) Synapse Connection: When the action potential reaches the end of the sensory neuron, it crosses a small gap called a synapse by releasing chemicals known as neurotransmitters.

4) Relay Neuron Activation: The neurotransmitters bind to receptors on a relay neuron. This binding can trigger an action potential in the relay neuron, allowing it to send the signal forward.

5) Continuing the Signal: The relay neuron processes the information and quickly transmits the action potential along its axon toward a motor neuron.

6) Motor Neuron Response: Finally, the motor neuron receives the impulse and sends it to the appropriate muscle or gland, causing a reaction (like moving away from heat).

Question 20

Why does the sensory neurone not connect to the motor neurone directly

Answer 20

Relay neurones serve as connections that allow for more flexible responses and modulation, which would not be possible if the connection was direct.

Question 21

What is the PNS

Answer 21

• peripheral nervous system
• detects a stimulus from its surrounding environment
• part of nervous system other than brain and spinal chord

Question 22

What are effectors

Answer 22

Muscles or glands that respond to a change in stimuli. Muscles contract, and glands respond by releasing hormones