Homeostasis and Response

Question 1

What is Homeostasis?

Answer 1

Homeostasis is the maintenance of a constant internal environment

Question 2

A homeostatic system is made up of five components

Answer 2

• Stimulus
• Receptor
• Control Centre
• Effector
• Response

Question 3

Negative Feedback - Too Cold

Answer 3

1. Hair stands up
2. Muscle contraction
3. Vasoconstriction

Question 4

Negative Feedback - Too Hot

Answer 4

1. Hair lays flat
2. Sweating
3. Vasodilation

Question 5

Central Nervous System contains….

Answer 5

• brain

- spinal cord

Question 6

Peripheral Nervous System contains….

Answer 6

• consists of all other nerves

Question 7

Nerve Cell components

Answer 7

• Dendrite
• Nucleus
• Axon
• Cell Membrane
• Nerve Ending
• Cytoplasm

Question 8

Communication in the nervous system

Answer 8

Stimulus to Receptor to Sensory Neurone to Relay neurone to Motor neurone to Effector to response

Question 9

Why do we need a myelin sheath ?

Answer 9

The myelin sheath insulates the axon and speeds up the transmission of electrical impulses.

Question 10

Sensory Neurones…..

Answer 10

They carry electrical impulses from receptors towards the CNS

Question 11

How do neurones communicate with each other….

Answer 11

• Neurones
  communicating with each other using junctions known as synapses
• This is done using chemical messengers

Question 12

SYNAPSES

Answer 12

LEARN

Question 13

NEUROMUSCULAR JUNCTIONS

Answer 13

LEARN

Question 14

Reflex Actions

Answer 14

quick automatic responses which do not require conscious processing or input from the brain in order to occur

Question 15

REFLEX ARC

Answer 15

LEARN

Question 16

Key Parts of the Brain

Answer 16

• Cerebral Cortex
• Hypothalamus
• Pituitary Gland
• Cerebellum
• Medulla

Question 17

The Medulla Function

Answer 17

• responsible for controlling unconscious activities

Question 18

Cerebellum

Answer 18

• behind the medulla
• responsible for co-ordinating our movement and our balance
• responsible for maintaining posture and equilibrium

Question 19

Hypothalamus

Answer 19

• regulates speech , temperature and the water balance in our body

Question 20

Pituitary Gland

Answer 20

• secretes several key hormones. including those that regulate our metabolism, sexual developments, growth and our general functioning
• receives input from the hypothalamus on which hormones to secrete.

Question 21

Cerebrum

Answer 21

• split into two hemispheres
• controls a lot of our higher functions such as language and speech
• outer layer known as the cerebral cortex.

Question 22

The Mammalian Eye

Answer 22

• light enters the eye through our pupil, where it is focused onto the retina
• from there the image is sent via the optic nerve to the brain

Question 23

Parts of the Eye

Answer 23

• iris
• pupil
• cornea
• cillary muscle
• lens
• conjunctiva
• retina
• fovea
• optic nerve
• lens

Question 24

PHOTORECEPTOR CELL

Answer 24

LEARN

Question 25

Vitreous Humour

Answer 25

Gel like substance that makes up the bulk if the eyeball, helps eye hold its spherical shape

Question 26

The Sclera

Answer 26

Retina protected by a thick connective tissue coat

Question 27

Choroid

Answer 27

Retina is nourished by a vascular choroid layer which lie below the sclera

Question 28

Iris

Answer 28

colour, controls how much light is let into the eye

Question 29

Sclera

Answer 29

is the white outer layer, protects the eye from injury

Question 30

Conjunctiva

Answer 30

a mucous membrane which lines the eyelids and covers the front of the eye

Question 31

Pupil Reflex

Answer 31

the amount of light entering the eye is controlled by a reflex action the size of the pupil changes in response to bright or dim light. This is controlled by the muscles of the iris

Question 32

Lens function and location.....

Answer 32

Lens is located at the front of the eye, responsible for refracting the light that enters the eye, and focussing it onto the retina

Question 33

Ciliary body is controlled by and contains....

Answer 33

The ciliary body contains smooth muscle arrange in circular fashion and controlled by the autonomic nervous system

Question 34

What is accomodation

Answer 34

The ability of the lens to change its shape to focus near and distant objects is called accommodation.

Question 35

When the lens thins....

Answer 35

causing lesser refraction in order to focus on object that is far away

Question 36

When the lens thickens...

Answer 36

causing greater refraction in order to focus on an object that is nearby

Question 37

What is myopia ?

Answer 37

Short sightedness

Question 38

What is hyperopia ?

Answer 38

Long sightedness

Question 39

What lens do we use for myopia ?

Answer 39

concave lens

Question 40

What lens do we use for hyperopia ?

Answer 40

convex lens