Homeostasis fundamentals (FSL)

Question 1

what is homeostasis

Answer 1

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

Question 2

what does exercise do to the body

Answer 2

places demand on the body,,, respiration uses glucose to produce energy, this can cause the blood glucose concentration to fall. The athletes body temp will rise and hell lose water through sweating.

Question 3

homeostasis consists of ____ making sure that the internal conditions of the body stay as constant as possible

Answer 3

automatic control systems

Question 4

what can the automatic control systems in the human body involve

Answer 4

nervous system or hormones

Question 5

receptor cells detect changes in what

Answer 5

the environment,, such as the bodys internal conditions eg the glucose concentration

Question 6

other than internal conditions, what else do receptor cells detect change in?

Answer 6

bodys external conditions eg the temperature of the skin

Question 7

what do scientists call a change to the environment

Answer 7

a stimulus

Question 8

what do the receptors pass information to?

Answer 8

a coordination centre

Question 9

whats an example of a co-ordination centre

Answer 9

the brain, spinal cord or the pancreas

Question 10

what does the co-ordination centre do

Answer 10

receives and processes the information from the receptor cells then sends instructions to the effector

Question 11

whats an effector is a muscle or a gland

Answer 11

the job of the effector is to carry out the response / restore the optimum level

Question 12

whast the nervous system cycle

Answer 12

receptors detect a stimulus and send electrical impulses down neurones to the central nervous system this sends electrical impulses to the effector to bring about a response.

Question 13

what are effectors usually?

Answer 13

a muscle which contracts or a gland which secretes a hormone

Question 14

what happens when you touch a hot thing

Answer 14

first a stimulus is detected by a receptor, electrical impulses now pass from the receptor along a sensory neurone to the central nervous system, the chemical then diffuses across to a relay neurone in the cns where it triggers an electric impulse , this then passes across the relay neurone b4 reaching another synapse then another chemical is released,, the chemical; triggers and electrical impulse in the motor neurone,, the electrical impulse now passes down the motor neurone to an effector ,, the muscle now contracts and pulls away from the heat.

Question 15

what does the brain contain

Answer 15

billions of interconnected neurones

Question 16

the function of the cerebral cortex include what

Answer 16

language, memory and consciousness

Question 17

what does the cerebellum control

Answer 17

balance and co-ordinates our movements

Question 18

what does the medulla control

Answer 18

our heart rate and our breathing rate

Question 19

why is studying/treating the brain difficult ?

Answer 19

its protected by the skull so is v tricky to access ,, the structures of the brain are v complex & the brain is extremely delicate and easy to damage

Question 20

how can we look at the effects on a persons behaviour

Answer 20

by electrically stimulating different parts

Question 21

what does the eye contain

Answer 21

receptors sensitive to both light intensity and also the colour of light

Question 22

What is the first step of the eye

Answer 22

light rays pass through the transparent front of the eye called the cornea

Question 23

whats the job of the cornea

Answer 23

start the focussing of the light rays

Question 24

whats the 2nd step of the eye

Answer 24

the light rays then pass through the pupil in the centre of the eye

Question 25

whats the job of the lens

Answer 25

to focus the light rays onto the back of the eye

Question 26

what is accomodation

Answer 26

the lens changing shape to allow it to focus on distant or near objects

Question 27

what does the retina contain and what do they do

Answer 27

receptor cells for light, they allow us to detect light intensity and light colour,, the receptor cells sent electrical impulses to the optic nerve to the brain

Question 28

whats the white part of the eye an what does it do?

Answer 28

the sclera and its the tough outer structure protects the eye

Question 29

what do the ciliary muscles and suspensory ligaments do?

Answer 29

allow us to focus on distant/ near objects

Question 30

whats the job of the iris

Answer 30

to control the sizeof the pupil

Question 31

what happens when you enter a dark room (in the eye)

Answer 31

the amount of light entering the eye is low. this drop in light intensity is sensed by light receptors in the retina and these send electrical impulses to the brain. The brain then sends electrical impulses to specific muscles in the iris. These msucles contract causing the pupil to become larger , allowing more light into the eye

Question 32

by contracting or relaxing, the ciliary muscles can do what?

Answer 32

the thickness of the lens

Question 33

when the cilliary muscle contracts, the suspensory ligaments do what?

Answer 33

loosen,, the lens is now thicker and refracts light rays more strongly

Question 34

when the ciliary muscle relaxes, the suspensory ligaments do what?

Answer 34

They pulled tight; the lens is now pulled thin and only slightly refracts light rays b

Question 35

what happens regarding focus on objects that are far away?

Answer 35

light from distant objects needs to be focused only a relatively small amount so ciliary muscles relax and suspensory ligaments are pulled tight so the lens is pulled thin,, bc of this,, the light rays are only slightly refracted ,, light rays are now focused to a point on the retina

Question 35

what happens in hyperopia

Answer 35

long sight is also called hyperopia ,, the eyeball is too short so the light is focused behind the retina, in some cases, the lens becomes less elastic ,, in this case the lens cant become thick enough to focus on near objects

Question 36

how can hyperopia be treated

Answer 36

convex lenses , these partially focus the light before it enters the eye

Question 37

what happens in myopia

Answer 37

the eyeball can be too long so the light is focused at the point in front of the retina, it can also be caused when the lens is too thick , the light is focused infront of the retina

Question 38

how can myopia be treated

Answer 38

concave lenses to partially unfocus the light before it enters the eye

Question 39

what do scientists call the part of the brain that controls temp

Answer 39

the thermoregulatory centre

Question 40

what does the thermoregulatory centre contain

Answer 40

receptors which are sensitive to the temperature of the blood,, the skin also contains these receptors

Question 41

what do receptors in the skin do

Answer 41

these send electrical impulses down sensory neurones to the thermoregulatory centre

Question 42

what is flushing

Answer 42

under the surface of the skin, we have a fine network of blood capillaries, these are supplied with blood by the blood vessels, if we get too hot the blood vessels dilate (get wider) this is vasodilation,, due to dilation, more blood is flowing through he capillaries , heat can transfer out of the blood so body temp returns to normal

Question 43

what happens if the body temp falls to low

Answer 43

blood vessels supplying the capillaries constrict in other words they become narrower, this is vasoconstriction ,, less blood now flows through the capillaries and less heat is lost from the body

Question 44

other than vasoconstriction,, what else happens when our body temp drops too low

Answer 44

shivering,,, when we shiver our skeletal muscles contract,, to generate energy for this contraction the muscle cells increase their rate of respiration, this releases heat

Question 45

what happens if our body temperature falls too low

Answer 45

we also stop sweating