b10

Question 1

what is homeostasis?

Answer 1

the regulation of internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.

Question 2

what are receptors?

Answer 2

cells which detect stimuli - a change in the environment

Question 3

what is the coordination center?

Answer 3

brain/spinal chord/ pancreas. they recieve and process information from receptors

Question 4

what are effectors?

Answer 4

muscles or glands which bring about responses which restore optimum levels.

Question 5

how is the nervous system adapted to it’s function?

Answer 5

they contain neurones with axons that can be over a meter in length which is more efficient than having many neurons as less time is wasted transferring electrical impulses from one cell to another.

Question 6

describe what happens when there is a stimulus

Answer 6

the info from the receptors passes along cells (neurons) as electrical impulses to the CNS - brain or spinal chord. the CNS coordinates the response of the effectors which might be muscles contracting or glands secreting hormones

Question 7

what is a reflex action?

Answer 7

an automatic and rapid action that does not involve the conscious part of the brain.

Question 8

what is the sensory neuron?

Answer 8

carries impulses from sense organs to CNS

Question 9

what is the relay neuron

Answer 9

found inside CNS and connect sensory and motor neurons

Question 10

what is motor neuron?

Answer 10

carries impulses from CNS to effectors - muscles or glands

Question 11

what is a synapse?

Answer 11

the gaps between neurones through which electrical impulses pass through in the form of a neurotransmitter

Question 12

what is the brain

Answer 12

made up of billions of interconnected neurones and has different regions that carry out different functions

Question 13

what does the cerebral cortex do?

Answer 13

outer layer of brain. responsible for intelligence, memory, consciousness and personality

Question 14

what does the cerebellum do?

Answer 14

under cerebral cortex and manages balance, muscle coordination and movement

Question 15

what does the medulla do?

Answer 15

controls unconscious activities such as heart rate and breathing

Question 16

why is investigating and treating the brain hard?

Answer 16

it is very complex and delicate and because different regions cannot be studied in isolation

Question 17

how can neuroscientists study the brain?

Answer 17

they can study patients with brain damage, they can electrically stimulate different parts of the brain and use MRI scanning technigues

Question 18

function of cornea

Answer 18

transparent lens that refracts light as it enters the eye

Question 19

function of iris

Answer 19

controls how much light enters the pupil

Question 20

function of the lens

Answer 20

transparent disc that can change shape to focus light onto the retina

Question 21

function of optic nerve

Answer 21

sensory neuron that carries impulses between the eye and the brain

Question 22

function of pupil

Answer 22

hole that allows light to enter the eye

Question 23

pupil reflex in dark light

Answer 23

receptors detect change in environment.
impulse passes along (sensory) neurone - the optic nerve - to the relay neuron in the coordinator which passes to the motor neurons which are the muscles in the eyes:
radial muscles contract and circular muscles relax
the pupil dilates (widens)
so more light enters the eye

Question 24

pupil reflex in bright light

Answer 24

receptors detect change in environment.
impulse passes along (sensory) neurone - the optic nerve - to the relay neuron in the coordinator which passes to the motor neurons which are the muscles in the eyes:
radial muscles relax and circular muscles contract
the pupil constricts
less light enters the eyes

Question 25

what is accomodation?

Answer 25

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

Question 26

what happens when you focus on a near object?

Answer 26

the ciliary muscles contract, so ciliary muscles have a smaller diameter so suspensory ligaments loosen / slacken, so lens thickens or lens becomes more curved / rounded. light is refracted more - bends more, so light rays / image focused on retina.

Question 27

what happens when you focus on a distant object?

Answer 27

the ciliary muscles slacken so they have a larger diameter, the suspensory ligaments tighten so lens becomes thinner. light is refracted less so then the light rays focus on the retina.

Question 28

what is myopia and what happens?

Answer 28

short sightedness - the eye is too elongated or the lens is too thick so the image is focused infront of the retina

Question 29

function of retina

Answer 29

contains light receptor cells - rods and cones.

Question 30

what is hyperopia and what happens?

Answer 30

the eyeball is too short so the image is brought to focus behind the retina.

Question 31

how do spectacle lenses help correct eye problems?

Answer 31

concave - corrects the rays so they focus on retina (myopia)
convex - refracts light rays so that they focus on the retina (hyperopia)

Question 32

what are some other technologies that help correct vision?

Answer 32

hard and soft contact lenses, laser surgery to change the shape of cornea, and a replacement lens in the eye