Topic 5 - Homeostasis and Response

Question 1

What is homeostasis?

Answer 1

Maintenance of a constant internal environment

Question 2

What is homeostasis needed for?

Answer 2

Enzyme action and cell function

Question 3

Three things which homeostasis controls?

Answer 3

Blood Glucose Concentration
Body Temperature
Water Levels

Question 4

What do all control systems have?

Answer 4

Receptors - Cells that detect stimuli
Coordination Centres - Process information received from receptors
Effectors - Muscle of gland which carry out responses accordingly

Question 5

Steps on how the nervous system reacts accordingly to a stimuli?

Answer 5

Receptor cells convert stimulus into an electrical impulse
Electrical impulse travels along sensory neurons to the CNS
Information is processed at the CNS and appropriate response is coordinated sending electrical impulse via the motor neurone back to the effectors
The effectors carry out the response

Question 6

What are reflexes?

Answer 6

Automatic response which take place before you have time to think

Question 7

Function of the cerebellum?

Answer 7

Controls movement of muscles, rounded structure towards the back of your brain

Question 7

What are synapses?

Answer 7

Gaps between two neurones

Question 8

Reflex arc

Answer 8

Stimulus detected by receptors
Impulses sent along sensory neuron
CNS passes to relay neuron
Impulses sent along a motor neuron
Impulse reaches an effector and results in appropriate response

Question 9

Steps on how synapse pass on information

Answer 9

When impulse reaches the end of the first neuron a chemical is released into the synapse
This chemical diffuses across the synapse
When the chemical reaches the second neuron, it triggers the impulse to begin again in the next neuron

Question 10

Function of the Cerebral Cortex?

Answer 10

Controls consciousness, intelligence, memory and language and is the outer part of your brain

Question 10

Different components of the brain

Answer 10

Cerebral Cortex
Cerebellum
Medulla

Question 10

What a reaction time?

Answer 10

Time taken to respond to a stimuli

Question 11

Function of the medulla?

Answer 11

Controls unconscious actions such as breathing and heart rate; Found in the brain stem in front of the cerebellum

Question 11

Ways neuroscientists can map out the regions in the brain?

Answer 11

Studying patients with brain damage
Electrically stimulating different areas of the brain
Use MRI

Question 12

Why is investigating the brain function and treating brain damage difficult?

Answer 12

Is complex and delicate
Easily Damaged
Drugs given to treat diseases cannot always reach the brain due to membranes surrounding
It is not fully understood what part of the brain does what

Question 13

How can studying a patient with brain damage give us a better understand of the brain?

Answer 13

By seeing the effects on an individual following the damages on the certain part of the brain

Question 14

How can electrically stimulating the brain give us a better understanding of the brain?

Answer 14

Passing electrodes in the brain damage certain areas providing information on the role of the area

Question 15

How can MRI scans give us a better understanding of the brain?

Answer 15

Magnetic response can be used to create an image of the brain and can show which part of a brain is affected by a tumour

Question 16

Whats the retina and the function?

Answer 16

Layer of light sensitive cells at the back of the eye. When light hits these are stimulated and impulses are sent to the brain to create an image

Question 17

Function of the optic nerve?

Answer 17

Nerve that leaves the eye to the brain. Carries impulses from the retina to the brain

Question 18

Function of sclera?

Answer 18

White outer layer, which supports structures inside the eyes. Strong to prevent damage to the eye

Question 19

Function of the cornea?

Answer 19

See through layer at the front of the eye. Allows light through and curved surface bends light to the retina

Question 20

Function of the iris?

Answer 20

Muscles which surround the pupil. Contract or relax to alter size of pupil

Question 21

Function of Ciliary muscles and Suspensory Muscles?

Answer 21

Hold the lens in place. They control its shape

Question 22

Process of accommodation to focus on a distant object?

Answer 22

Ciliary Muscles Relax
Suspensory Ligaments tighten
Lens becomes thinner - light is refracted less

Question 23

What happens to the iris during bright and dim light?

Answer 23

Bright Light- Circular Muscles contract and radial muscles relax to prevent damage to the retina
Dim Light - Circular muscles relax and radial muscles contract so more light can enter and creating a better image

Question 23

What’s Long sightedness called, and reason?

Answer 23

Hyperopia
Lens is too flat, so not enough light can be refracted

Question 23

Process of accommodation to focus on a near object?

Answer 23

Ciliary Muscles contract
Suspensory ligaments loosen
Lens becomes thicker and more curved - light is refracted more

Question 24

What’s short sightedness called, and reason?

Answer 24

Myopia where the lens is too curved so distant objects appear blurry