Edexcel Biology Gcse - Coordination And Control - The Nervous System Part 1

Question 1

Accomidation
def

Accepted Answer

The process of changing the shape of the lens of the eye to focus on near or distant objects

Question 2

Axon
def

Accepted Answer

The long part of a nerve cell along which the electrical signal quickly moves

Question 3

Cancer
def

Accepted Answer

A disease caused by normal cells changing so that they grow and divide in an uncontrolled way. The uncontrolled growth causes a lump called a tumour to form

Question 4

Cell membrane
def

Accepted Answer

A selectively permeable membrane surrounding the cell and controlling the entry and exit of materials

Question 5

Cerebellum
def

Accepted Answer

The part of the brain that controls balance and co-ordination

Question 6

Convex lens
def

Accepted Answer

A lens that is thicker in the centre than at the edges, and which converges light

Question 7

Diffuse
def

Accepted Answer

When particles spread out from a region of higher concentration to a region of lower concentration

Question 8

Effector
def

Accepted Answer

The organ, tissue or cell that produces a response

Question 9

Medulla
def

Accepted Answer

The part of the brain controlling breathing, heart rate and peristalsis

Question 10

MRI

Accepted Answer

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

Question 11

Neurone

Accepted Answer

Nerve cells are called neurones. They are adapted to carry electrical impulses from one place to another. A bundle of neurones is called a nerve.

Question 12

Neurotransmitter
de

Accepted Answer

Chemical involved in passing nerve impulses from one nerve cell to the next across a synapse

Question 13

Optimum
def

Accepted Answer

The best or most appropriate - for instance, the conditions under which an enzyme works best (eg temperature and pH)

Question 14

Receptors

Accepted Answer

Organs which recognise and respond to stimuli. Receptors are groups of specialised cells. They detect a change in the environment and stimulate electrical impulses in response. Sense organs contain groups of receptors that respond to specific stimuli.

Question 15

Stimulus
def

Accepted Answer

Something that sets off a reaction in the nervous system, for example, light, heat, sound, gravity, smell, taste, or temperature. These changes in the environment are detected by receptors in an organism. The plural is stimuli

Question 16

Synapse
def

Accepted Answer

A tiny gap at the junction between two nerve cells, which nerve signals must cross

Question 17

the nervous system.
The conditions inside our body must be carefully controlled if the body is to function effectively. The conditions are controlled in two ways with chemical and nervous responses.
All control systems include:

Accepted Answer

cells called receptors, which detect stimuli
the coordination centre, such as the brain, spinal cord or pancreas, which receives and processes information from receptors around the body
effectors bring about responses, which restore optimum levels, such as core body temperature and blood glucose levels
effectors include muscles and glands, and so responses can include muscle contractions or hormone release

Question 18

What are the three main type of neurone?

Accepted Answer

sensorymotorrelay

Question 19

Features that all 3 main types of nuerones have in common.

Accepted Answer

A long fibre (axon) which is insulated by a fatty (myelin) sheath. They are long so they can carry messages up and down the body.
Tiny branches (dendrons) which branch further as dendrites at each end. These receive incoming impulses from other neurones.

Question 20

Where two neurones meet there is a small gap called a synapse. Here 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.

Accepted Answer

1) an electrical impulse travels along the first axon
2) this triggers the nerve-ending of a neurone to release chemical messengers called neurotransmitters
3) these chemicals diffuse across the synapse (the gap) and bind with receptor molecules on the membrane of the second neurone
4) the receptor molecules on the second neurone bind only to the specific neurotransmitters released from the first neurone
5) this stimulates the second neurone to transmit the electrical impulse.

Edexcel Biology Gcse - Coordination And Control - The Nervous System Part 1

Accomidation def

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Term	Definition
Accomidation def	The process of changing the shape of the lens of the eye to focus on near or distant objects
Axon def	The long part of a nerve cell along which the electrical signal quickly moves
Cancer def	A disease caused by normal cells changing so that they grow and divide in an uncontrolled way. The uncontrolled growth causes a lump called a tumour to form
Cell membrane def	A selectively permeable membrane surrounding the cell and controlling the entry and exit of materials
Cerebellum def	The part of the brain that controls balance and co-ordination
Convex lens def	A lens that is thicker in the centre than at the edges, and which converges light
Diffuse def	When particles spread out from a region of higher concentration to a region of lower concentration
Effector def	The organ, tissue or cell that produces a response
Medulla def	The part of the brain controlling breathing, heart rate and peristalsis
MRI	Magnetic Resonance Imaging - A computer that can scan the human body using magnetic fields and radio waves, used in medicine
Neurone	Nerve cells are called neurones. They are adapted to carry electrical impulses from one place to another. A bundle of neurones is called a nerve.
Neurotransmitter de	Chemical involved in passing nerve impulses from one nerve cell to the next across a synapse
Optimum def	The best or most appropriate - for instance, the conditions under which an enzyme works best (eg temperature and pH)
Receptors	Organs which recognise and respond to stimuli. Receptors are groups of specialised cells. They detect a change in the environment and stimulate electrical impulses in response. Sense organs contain groups of receptors that respond to specific stimuli.
Stimulus def	Something that sets off a reaction in the nervous system, for example, light, heat, sound, gravity, smell, taste, or temperature. These changes in the environment are detected by receptors in an organism. The plural is stimuli
Synapse def	A tiny gap at the junction between two nerve cells, which nerve signals must cross
the nervous system. The conditions inside our body must be carefully controlled if the body is to function effectively. The conditions are controlled in two ways with chemical and nervous responses. All control systems include:	cells called receptors, which detect stimuli the coordination centre, such as the brain, spinal cord or pancreas, which receives and processes information from receptors around the body effectors bring about responses, which restore optimum levels, such as core body temperature and blood glucose levels effectors include muscles and glands, and so responses can include muscle contractions or hormone release
What are the three main type of neurone?	sensory motor relay
Features that all 3 main types of nuerones have in common.	A long fibre (axon) which is insulated by a fatty (myelin) sheath. They are long so they can carry messages up and down the body. Tiny branches (dendrons) which branch further as dendrites at each end. These receive incoming impulses from other neurones.
Where two neurones meet there is a small gap called a synapse. Here 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.	1) an electrical impulse travels along the first axon 2) this triggers the nerve-ending of a neurone to release chemical messengers called neurotransmitters 3) these chemicals diffuse across the synapse (the gap) and bind with receptor molecules on the membrane of the second neurone 4) the receptor molecules on the second neurone bind only to the specific neurotransmitters released from the first neurone 5) this stimulates the second neurone to transmit the electrical impulse.
Receptors to effectors	Receptor cells detect a change in the environment (a stimulus) and start electrical signals along neurons. These move towards the central nervous system (CNS). The CNS is the brain and spinal cord. It coordinates the responses. Messages are then sent back along different neurones to muscles which contract or relax, and glands which secrete hormones. Muscles and glands are called effectors. Stimulus → receptor → coordinator → effector → response
Name the stimulus for each of these sense organs: Skin Tongue Nose Eye Ear	Skin - Touch, temperature Tongue - Chemicals (in food and drink, for example) Nose - Chemicals (in the air, for example) Eye - light Ear - sound
Effectors include muscles and glands. They produce a specific response to a detected stimulus. For example:	a muscle contracting to move an arm muscle squeezing saliva from the salivary gland a gland releasing a hormone into the blood.
features of a motor neurone	Dendrite Cytoplasm Nucleus Cell membrane Axon Nerve ending
reflex action \| part of reflex arc	There are different types of neurones that work together in a reflex action. This is an automatic and rapid response to a stimulus, which minimises any damage to the body from potentially harmful conditions, such as touching something sharp or hot. The pathway of a reflex action only travels through relay neurones in the spinal cord and not the brain in order to increase the speed of the reaction.