Coordination and control - The nervous system

Question 1

what do all control systems include?

Answer 1

-cells called receptors

-the coordination centre

-effectors

Question 2

what are receptors?
what do receptors do?

Answer 2

-groups of specialised cells.
-detect a detect stimuli and stimulate electrical impulses in response

Question 3

what is the purpose of the coordination centre?

Answer 3

receives and processes information from receptors around the body

Question 4

what do effectors do?

Answer 4

bring about responses

Question 5

what are nerve cells called?
-what are they adapted to do?

Answer 5

-neurones
-they are adapted to carry electrical impulses from one place to another

Question 6

what is a nerve?

Answer 6

a bundle of neurons

Question 7

what are the three main types of neurones?

Answer 7

sensory
motor
relay

Question 8

2 common features in neurones:

Answer 8

-A long fibre (axon) which is insulated by a fatty (myelin) sheath.

-Tiny branches (dendrons) which branch further as dendrites at each end.

Question 9

why are axons long?

Answer 9

They are long so they can carry messages up and down the body.

Question 10

what is the purpose of dendrons

Answer 10

to receive incoming impulses from other neurones.

Question 11

what is there between 2 neurons that meet?

Answer 11

a small gap called a synapse.

Question 12

what happens at a synapse?

Answer 12

-the electrical signal must be converted into a chemical one, which is converted back to an electrical one on the other side of the synapse where the next neurone starts.

Question 13

describe the process at which an electrical signal is converted into a chemical one, which is converted back to an electrical one on the other side of the synapse: (5)

Answer 13

-an electrical impulse travels along the first axon

-this triggers the nerve-ending of a neurone to release neurotransmitters

-neurotransmitters diffuse across the synapse and bind with receptor molecules on the membrane of the second neurone

-the receptor molecules on the second neurone bind only to the specific neurotransmitters released from the first neurone

-this stimulates the second neurone to transmit the electrical impulse.

Question 14

what is a stimulus?

Answer 14

a change in the environment

Question 15

describe the process for ‘receptors to effectors’: (4)

Answer 15

-stimulus is detected by receptor, which starts electrical signals along sensory neurons
-these move towards the central nervous system (CNS).
-CNS coordinates the responses.
-Messages are then sent back along motor neurones to the effectors

Question 16

what is the CNS?
-what does it do?

Answer 16

the central nervous systems is the brain and spinal cord.
-it coordinates the responses

Question 17

what are effectors?

Answer 17

muscles which contract or relax, or glands which secrete hormones.

Question 18

summarises how information flows from receptors to effectors in the nervous system in 5 steps:

Answer 18

Stimulus → receptor → coordinator → effector → response

Question 19

what is a reflex arc?

Answer 19

an automatic and rapid response to a stimulus, which minimises any damage to the body from potentially harmful conditions

Question 20

what does the reflex arc not involve?
-how is this beneficial?

Answer 20

the conscious part of the brain,
-to increase the speed of reactions, in turn reducing damage to the body

Question 21

describe the steps in a reflex arc: (4)

Answer 21

-receptor detects a stimulus
-sensory neurones send electrical impulses to relay neurones, which are located in the spinal cord.
-they connect sensory neurones to motor neurones.
-motor neurones send electrical impulses to an effector and effector produces a response

Question 22

what does the path of a relay neurone only travel through?

Answer 22

relay neurones in the spinal cord and not the brain

Question 23

what are the 3 main areas of the brain?

Answer 23

cerebral hemispheres
cerebellum
medulla

Question 24

description of the Cerebral hemispheres: (2)

Answer 24

-the cerebrum’s outer layer, it is split into two hemispheres and is highly folded.
-these two hemispheres make up the cerebral cortex.

Question 25

what does the cerebral cortex control?

Answer 25

• most of our senses, intelligence, personality, conscious thought and high-level functions, such as language and verbal memory

Question 26

function of the Cerebellum:

Answer 26

Controls balance, co-ordination of movement and muscular activity.

Question 27

function of the Medulla oblongata:

Answer 27

Controls unconscious activities such as heart rate and breathing rate.

Question 28

function of the Hypothalamus:

Answer 28

Regulates temperature and water balance within the body.

Question 29

what is MRI?

Answer 29

Magnetic Resonance Imaging - A computer that can scan the human body using magnetic fields and radio waves