Key Area 2 - Control And Communication

Question 1

What does the central nervous system consist of in mammals?

Answer 1

The brain and the spinal cord

Question 2

How is the CNS connected to all other parts of the body?

Answer 2

By the nerves

Question 3

Describe the function and the structure of the CEREBRUM

Answer 3

The large folded area of the brain which controls memory, personality and conscious thought

Question 4

Describe the structure and function of the CEREBELLUM

Answer 4

Found at the rear of the brain behind the medulla and controls balance and coordination of movement

Question 5

Describe the function of the MEDULLA

Answer 5

Controls heart and breathing rate

Question 6

What are the two main functions of the CNS?

Answer 6

To process information received from the senses

To then co-ordinate the body’s response

Question 7

Name the 3 receptors, their location in the body & their stimulus

Answer 7

• Photoreceptor , retina in eye , light
• Thermoreceptors , skin & hypothalamus , temperature
• Chemoreceptors , tongue & nose , chemicals

Question 8

What are the 3 main types of neurons & what are their functions?

Answer 8

Sensory neurons - to carry impulses from the receptors to the CNS
Inter neurons - located in CNS, transmit electrical impulses from the sensory to motor neurons
Motor neurons - carry impulses from CNS to the effectors

Question 9

What are neurones?

Answer 9

Specialised nerve cells which carry information, in the form of electrical nerve impulses, from the receptors to the CNS, and from the CNS to the effectors

Question 10

What are the three parts each neurone consists of?

Answer 10

1. Cell body ( containing cytoplasm and nucleus. The cell bodies are located in the brain and spinal cord)
2. Fibres which carry impulses into the cell bodies
3. Fibres carrying impulses away from the cell bodies

Question 11

What is a synapse?

Answer 11

The gap between adjoining neurones.

Question 12

What do nerve impulses arriving at a synapse cause?

Answer 12

Diffusion of a chemical substance (neurotransmitter), which crosses the gao and triggers off nerve impulses in the next neuron

Question 13

What are the 4 main functions of the brain?

Answer 13

• Receives impulses from all sensory organs in the body (ears,eyes,mise,tongue & skin)
  -Sends motor impulses to muscles and glands to control their function
  Co-ordinates bodily activities
  -Stores information (learning, memory, problem solving)

Question 14

A reflex action is…? (REMEMBER: RAIP)

Answer 14

• Rapid
• Automatic
• Involuntary (cannot be ignored)
• Protective

Question 15

Where do the nerve impulses pass through in a reflex action?

Answer 15

They pass through the spinal cord but not the brain, before a response is generated

Question 16

Why do reflex actions work so quickly?

Answer 16

As they do not require conscious control from the brain, in order to protect the body from damage

Question 17

Give 3 examples of reflex actions

Answer 17

Sneezing (causes violent expiration to blow out irritant material)
Pupil reflex (controls light intensity, protecting retina from damage) 
Knee jerk (protects the tendon)

Question 18

What makes up a reflex arc?

Answer 18

The structures involved and the nerve impulses responsible for reflex actions

Question 19

Explain the process of a reflex arc being set up

Answer 19

When an environmental stimulus triggers a nerve impulse st a receptor.(1) The impulse is transmitted along a sensory neurone (2) to the spinal cord, where it crosses a synapse (3) to an inter neurone. (4) The impulse passes across another synapse to a motor neurone (5) which then transmits it to an effector, usually a muscle (6).

Question 20

When a reflex arc operates, where are impulses also sent?

Answer 20

To the brain. Thus, although the spinal cord starts off the response, it is via n that we are made aware of what has happened.

Question 21

What is a hormone?

Answer 21

A chemical released into the bloodstream by endocrine glands, in one part of the body, that affects cells in other parts of the organism. Hormones are chemical messengers.

Question 22

A specific hormone can only affect what kind of cells?

Answer 22

Target cells, that have the specific protein receptor that can bind to the hormone.

Question 23

What does ‘CRP’ stand for?

Answer 23

Complementary Receptor Protein

Question 24

Give 2 examples of hormones, along with where they’re produced, the target organ and their effect.

Answer 24

Insulin - Pancreas - Liver & Skeletal Muscle - Triggers the production of enzymes which converts glucose to glycogen.
Glucagon - Pancreas - Kidney - Triggers the production of enzymes which converts glycogen to glucose.

Question 25

What are the jobs of insulin and glucagon?

Answer 25

To regulate glucose levels in the blood

Question 26

What happens when blood glucose concentration is too high?

Answer 26

Insulin is secreted into the blood (glucagon is not), the liver converts glucose into glycogen for storage in the liver, and the blood glucose level decreases

Question 27

What happens when the blood glucose concentration is too low?

Answer 27

Glucagon is secreted into the blood (insulin is not), the liver converts stored glycogen into glucose, and the blood glucose concentration increases.

Question 28

What is diabetes?

Answer 28

A disorder in which the blood glucose levels remain too high. There are two types of diabetes.

Question 29

What is Type 1 diabetes?

Answer 29

It is caused by a lack of insulin. Can be controlled by monitoring the diet and injecting insulin. People with type 1 diabetes must monitor their blood sugar levels throughout the day. It commonly begins in early adolescence.

Question 30

What is Type 2 diabetes?

Answer 30

It’s caused by a person’s body becoming resistant to insulin. It is often controlled by diet and exercise, as insulin injections have little effect. Link between rising obesity levels and type 2 diabetes