Homeostasis and Response

Question 1

What is homeostasis?

Answer 1

maintaining a stable internal environment in response to changes in both internal and external conditions

Question 2

Why does you body temperature need to stay at a stable temp?

Answer 2

cells need the right temperature to function properly and for enzyme action

Question 3

what are some automatic control systems in your body?

Answer 3

nervous and Hormonal communication

Question 4

What are the three main components which work together to maintain a steady condition?

Answer 4

receptors, coordination centres and effectors

Question 5

What is negative feedback?

Answer 5

your automatic control system so when something gets too low or high your body brings it back up

Question 6

explain what happens when something is too high?

Answer 6

• receptor detects a stimulus
• coordination center receives and processes information, then organises a response
• effector produces a response which counteracts the change and restores to optimum level

Question 7

What does the nervous system do?

Answer 7

detect and react to stimuli

Question 8

What is central nervous system?

Answer 8

spinal chord + brain

in mammals- sensory neurons and motor nuerons

Question 9

What are sensory neurones?

Answer 9

carry information as electrical impulses from the receptors to the CNS

Question 10

What are motor neurones?

Answer 10

carry electrical impulses from the CNS to effectors

Question 11

what are effectors?

Answer 11

all your muscles and glands which respond to nervous impulses

Question 12

What are receptors?

Answer 12

cells that detect stimuli

Question 13

What are the different types of receptors?

Answer 13

taste, sound, heat, light

Question 14

how do muscles react to effectors?

Answer 14

contract

Question 15

How do glands react to effectors?

Answer 15

secrete hormonmes

Question 16

What are neurones?

Answer 16

transmit information quickly to and from the brain

Question 17

What is a synapse?

Answer 17

the connection between two neurones
nerve signal is transferred by chemicals which diffuse across the gap
chemicals set off a new electrical signal in the next neurone

Question 18

What are reflexes?

Answer 18

help prevent injury

rapid and automatic

Question 19

What is a reflex arc?

Answer 19

the passage of information in a reflex (from receptor to effector)

Question 20

What do neurones in reflex arcs go through?

Answer 20

spinal chord or unconscious part of the brain

Question 21

What are relay neurones?

Answer 21

connect sensory neurons to motor nuerons

Question 22

describe the process from when a bee stings your finger?

Answer 22

• stimulus is detected by receptors, impulses are sent along a sensory neurone to a relay neurone in the CNS
• when the impulses reach a synapse between the sensory neurone and relay neurone, they trigger chemicals to be released
• causes impulses to be sent along the relay neurone
• when impulses reach a synapse between the relay and motor neurone the same thing happens, chemicals released which causes impulses to be sent along motor neurone
• impulses travel along the motor neurone to the effector
• muscle moves hand away from bee

Question 23

What is reaction time?

Answer 23

time it takes to respond to a stimulus

Question 24

What can reaction time be effected by?

Answer 24

age, gender or drugs

Question 25

how can reactions time be measured with a computer?

Answer 25

- clicking a mouse as soon as a stimulus changes on a screen

Question 26

What can computers do that humans can't?

Answer 26

give more precise reaction time because they remove the possibility of human error, more accurate and can't predict when to respond

Question 27

What is the brain made of?

Answer 27

billions of interconnected neurones

Question 28

What are the 4 main parts of the brain?

Answer 28

cerebral cortex, medulla, cerebellum, spinal chord

Question 29

what does the cerebral cortex do?

Answer 29

responcable for things like consciousness, intelligence, memory and language

Question 30

What does the medulla do?

Answer 30

controls unconscious activities, breathing and heart rate

Question 31

what does the cerebellum do?

Answer 31

muscle cooordination

Question 32

What are the three methods for studying the brain?

Answer 32

studying patients with brain damage, electrically stimulating the brain, MRI scans

Question 33

How can you electrically stimulate the brain?

Answer 33

by pushing a tiny electrode into the tissue and giving it a small zap of electricity. by examining what stimulating different parts of the brain does, it gives an idea of what parts do

Question 34

What is an MRI scan?

Answer 34

magnetic resonance imaging scanner that gives a detailed picture of the brains structures.

Question 35

LEARN EYE DIAGRAM

Answer 35

LEARN EYE DIAGRAM

Question 36

What is the sclera?

Answer 36

tough, supporting wall of eye

Question 37

What is the cornea?

Answer 37

transparent outer layer found at the front of the eye, it reflects light into eye

Question 38

What is the iris?

Answer 38

contains muscles that allow it to control the diameter of the pupil and therefor how much light eneters

Question 39

What is the lens?

Answer 39

focuses light onto the retina

Question 40

What is a retina?

Answer 40

contains receptor cells sensitive to light and colour

Question 41

What is the shape of the lens controlled by?

Answer 41

ciliary muscles and suspensory ligaments

Question 42

What is the optic nerve?

Answer 42

carries impulses from the receptors on the retina to the brain

Question 43

What happens when light detectors in the eye detect very bright light?

Answer 43

circular muscles in the iris contract and the radial muscles relax

Question 44

What happens when there is dim light?

Answer 44

circular muscles relax and radial muscles contract

Question 45

What is accommodation?

Answer 45

eye focuses light on the retina by changing the shape of the lens

Question 46

What happens when looking at a near object?

Answer 46

- ciliary muscles contract - suspensory ligaments slacken - lens becomes more curved - Increases amount of light refracted

Question 47

What happens when looking at a far object?

Answer 47

- ciliary muscles relax - suspensory ligaments pull tight - lens becomes less curved - decreases amount of light refracted

Question 48

What can't long sited people do?

Answer 48

focus on near objects

Question 49

When does a person become long sited?

Answer 49

when the lens is the wrong shape and doesn't refract the light enough. or the eyeball is too short

Question 50

What happens when you are long sited?

Answer 50

the image of a near object is bought into focus BEHIND the retina

Question 51

what is the medical term for long sitedness?

Answer 51

hyperopia

Question 52

What lens corrects long sitedness?

Answer 52

convex lens

Question 53

What can't short sited people do?

Answer 53

focus on distant objects

Question 54

When does shortsitedness occur?

Answer 54

When the lens is the wrong shape and refracts the light too much or eyeball is too long

Question 55

What happens when you are short sighted?

Answer 55

image focuses infront of the retina

Question 56

What lens can you use to correct shortsightedness?

Answer 56

concave lens

Question 57

What is the medical term for shortsightedness?

Answer 57

myopia

Question 58

What are three alternatives to wearing glasses?

Answer 58

contact lenses laser eye surgery replacement lens surgery

Question 59

Explain contact lenses?

Answer 59

thin lenses that sit on the surface of the eye, lightweight and almost invisible - two types, hard and soft

Question 60

Explain laser eye surgery?

Answer 60

laser can be used to vaporise tissue, changing the shape of the cornea. sergeon can be very precise but there is a risk to complications

Question 61

explain replacement lens surgery?

Answer 61

natural lens is removed and an artificial one is inserted , high risk and could damage retina