homeostasis and control

Question 1

what is homeostasis?

Answer 1

regulation of internal conditions in the body to mantain optimum conditions for body functions

Question 2

function of cerebrum/ cerebral cortex

Answer 2

• outermost zone of brain
• controls consciousness, intelligence, memory, language and emotion

Question 3

function of cerebellum

Answer 3

controls coordination, precision, accurate timing

Question 4

function of medulla

Answer 4

controls unconscious activity eg breathing, peristalsis, heart rate etc.

Question 5

what are the 2 types of muscles in the iris?

Answer 5

1. radial
2. circular

Question 6

what happens to the iris in bright light?

Answer 6

• less light should enter eye to protect retina from damage
• circular muscles contract
• radial muscles relax
• pupil becomes smaller and more contracted

Question 7

what happens to the iris in dim light?

Answer 7

• more light needs to enter the eye
• radial muscles contract
• circular muscles relax
• pupil becomes bigger (dialated)

Question 8

function of retina

Answer 8

light sensitive layer which sends signals to optic nerve

Question 9

function of optic nerve

Answer 9

sends signals to the brain

Question 10

function of scelra

Answer 10

tough and fibrous > protects interior components of eye from injury

Question 11

function of ciliary muscles

Answer 11

pull the lens for focusing

Question 12

function of iris

Answer 12

controls amount of light entering the eye

Question 13

function of cornea

Answer 13

lets light into eye, begins focusing light onto retina

Question 14

function of iris (and pupil)

Answer 14

pupil - hole in the iris
iris controls amount of light entering the light through the contraction and relaxation of the radial and circular muscles

Question 15

function of suspensary ligaments

Answer 15

hold the lens in place

Question 16

what is accomodation?

Answer 16

when the shape of the lens changes to focus light on the retina

Question 17

what happens to the eye to look at near object? (4)

Answer 17

1. cliary muscles contract
2. suspensery ligaments relax
3. lens become fat (more curved)
4. this increases the amount by which it refracts light

Question 18

what happens to the eye to look at distants object? (4)

Answer 18

1. cilary muscles relax
2. suspensary ligaments pull tight
3. lens becomes thin (less curved)
4. light doesn’t refract as much

Question 19

what is myopia?

Answer 19

• short sightedness (unable to focus on distant objects)
• lens is wrong shape or eyeball is too long
• refracts light too much, focal point is in front of retina

Question 20

how can myopia be treated with glasses?

Answer 20

glasses with a concave lens (curved inwards) so that light focuses on the retina

Question 21

what is hyperopia?

Answer 21

• long-sightedness (can’t focus on near objects)
• lens is wrong shape and doesn’t refract light enough or eyeball is too short
• focal point is bhind the retina

Question 22

how can hyperopia be treated with glasses?

Answer 22

glasses with a convex lens (curved outwards) which refracts the light rays so they focus onto the retina

Question 23

what can be used to treat eye defects? (4)

Answer 23

• contact lenses
• glasses
• laser eye surgery (correct eye defects by shaving off some cornea - most effective for myopia)
• replacement lens sugery (natural lens replaced by artificial one)

Question 24

how can neuroscientists map the brain? (3)

Answer 24

• studying patients with brain damage eg phineas gage (man with pole through head)
• electrically stimulating the brain
• MRI scans

Question 25

what are reflexes?

Answer 25

an action which is rapid and automatic (doesn't involve the conscious part of the brain)

Question 26

how do reflexes work? (7) (describe reflex arc)

Answer 26

1. stimulus detected by sensory receptors 2. electrical impulse travels along sensory neurone towards centeral nervous system (cns) 3. electrical impulse converted into chemical message at synapse 4. relay neurone quickly decides on a response, send a messgae via another synapse to a motor neurone 5. motor neurone carries an electrical impulse to an effector 6. effector preforms action 7. relay neurone also sends a message to the brain, but this takes longer than the actual reaction

Question 27

what do reflexes do / role of refexes?

Answer 27

protect body from danger and prevent further damage of our tissues

Question 28

what are the different parts of the nervous system?

Answer 28

1. central nervous system (brain and spinal cord) 2. sensory neurones 3. motor neurones 4. effectors

Question 29

what are sensory neurones?

Answer 29

carry information from the receptors to CNS

Question 30

what are motor neurones?

Answer 30

neurones that carry electrical impulses from CNS to effectors

Question 31

what are effectors?

Answer 31

all your muscles and glands which respond to nervous impulses - muscles contract - glands excrete hormones

Question 32

what are synapses?

Answer 32

connection (gap) between 2 neurones

Question 33

what can and can't travel through synapses?

Answer 33

- electrical impusles cannot travel across - instead a chemical message (NEUROTRANSMITTER) diffuses across gap to stimulate a new electrical impulse in the next neurone

Question 34

what are receptors?

Answer 34

- cells that detect stimuli (any change in the environment) - can also form part of larger organs eg retina is covered in light receptor cells

Question 35

describe how info is carried from receptors is carried to brain to coordinate the response

Answer 35

1. receptors detect stimuli 2. sensory neurones carry the info from receptors to CNS 3. CNS recieves and processes info 4. CNS sends electrical impulse to the effector through the motor neurones

Question 36

what are the main functions of the nervous system? (2)

Answer 36

1. detect any changes in the environment eg stimuli 2. coordinate our bodies ad behaviours

Question 37

what are coordination centres?

Answer 37

parts of the nervous system that recieves from the receptors ad them coordinates a response

Question 38

accommodation = ?

Answer 38

1/ near distance - 1/far distance (measure of how easily your lens can change shape) - higher the number, the more flexible the lens

Question 39

# rpa 7 ruler drop test - control variables (6)

Answer 39

1. type + weight of ruler 2. height it is dropped from 3. way the ruler is dropped (no force used ) 4. using same hand to catch ruler each time 5. keep fingers same distance apart before catching 6. carry out experiment with lower handing resting on the table

Question 40

ruler drop test - independent variable

Answer 40

dominant (writing) hand or non-dominant (non writing) hand

Question 41

# rpa 7 ruler drop test - dependent variable

Answer 41

reaction time (s)

Question 42

ruler drop test - method (7)

Answer 42

1. participants sits with their writing hand over the edge of the table 2. experimenter holds the ruler in line with the thumb and forefinger of the parcipitants 3. experimenter drops the ruler randomly 4. participants catches ruler 5. read reactio distance distance from top of the thumb and record in table 6. swap hands and repeat (make sure same hand (writing/ non-writing) goes first for each participant 7. repeat with experimenter and participant swapped (plot as bar chart)