Biology Homeostasis & response Sept 2018

Question 1

What is the definition of homeostasis?

Answer 1

Homeostasis is the maintenance of a constant internal environment

Question 2

What conditions does your body need to keep stable in order to survive?

Answer 2

• Body glucose concentration
• Body temperature
• Water balance

Question 3

What is the CNS?

Answer 3

The Central Nervous System is the name given to the brain and spinal chord as they are the bridge carrying nerves.

Question 4

What is a receptor?

Answer 4

A receptor is a cell or group of cells at the beginning of a pathway of neurons that detects a change and sends an electrical impulse

Question 5

What are the three types of neurons?

Answer 5

Sensory, relay and motor

Question 6

What is the sensory neuron?

Answer 6

A neuron that carries an electrical impulse from a receptor towards the CNS

Question 7

What is a relay neuron?

Answer 7

A neuron that carries an electrical impulse around the CNS

Question 8

What is a motor neuron?

Answer 8

A neuron that carries an electrical impulse away from the CNS to a effector

Question 9

What is an effector?

Answer 9

A muscle or gland

Question 10

What is the synapse?

Answer 10

A gap between the axon of one nerve and the dendrites of another where chemical neurotransmitters transmit the impulse

Question 11

What is a dendrite?

Answer 11

The branched beginnings of neurons, which can detect chemical neurotransmitters and start another impulse

Question 12

What is an axon?

Answer 12

The root like part of a neuron where chemical neurotransmitters are sent through the synapse.

Question 13

What is a reflex response and reflex arc?

Answer 13

Reflex response - An automatic response that you do
not think about.
Reflex arc - The route of an electrical impulse that
avoids the brain to save time so helps
prevent damage to your body.

Question 14

What is the cerebral cortex?

Answer 14

The outer layer of the brain, which plays an important role in consciousness.

Question 15

What is the cerebellum?

Answer 15

A part of the back of the brain that coordinates muscular activity.

Question 16

What is the medulla oblongata?

Answer 16

A part of your brain above the spinal chord that controls your breathing and heart rates.

Question 17

What is accommodation?

Answer 17

Changing the shape of the lens in your eye to focus on near and far objects.

Question 18

What are cones and rods?

Answer 18

Cones - Light-sensitive receptor cells on your retina in
the back of your eye that let you see in colour.
Rods - Light-sensitive receptor cells on your retina in
the back of your eye that let you see in low
light conditions.

Question 19

What are the parts of the eye and their functions?

Answer 19

Cornea - Refracts light through the pupil. (transparent
part of eye)
Lens - Refracts light to be focused on the retina.
(biconvex structure found behind the pupil)
Iris - Controls the size of the pupil by relaxing and
contracting. (coloured part of eye)
Ciliary Body - Relaxes and contracts to change the
shape of the lens during accommodation.
Choroid - Provides oxygen and nourishment to the cells
of the retina.
Retina - The layer of receptors in your eye containing
two types of light sensitive cells called rods
and cones.
Fovea - Responsible for your sharpest vision.
Sclera - The white of the eye. Protects the eye.
Optic nerve - Connects the eyes with the brain.