homeostasis and response

Question 1

what is homeostasis?

Answer 1

homeostasis is the regulation of the internal conditions of a cell or organism in response to internal external changes.

Question 2

why is homeostasis important?

Answer 2

homeostasis keeps conditions constant for enzyme action and cell functions

Question 3

homeostasis is in control of:

Answer 3

• blood glucose concentration
• body temperature
• water and ion levels

Question 4

control systems of homeostasis involve:

Answer 4

• responses using nerves

- chemical responses using hormones

Question 5

control systems include:

Answer 5

• cells called receptors
• coordination centres
• effectors

Question 6

what do receptors do?

Answer 6

they detect stimuli

Question 7

stimuli

Answer 7

changes in the environment

Question 8

coordination centres examples

Answer 8

brain, spinal cord, pancreas

Question 9

what do coordination centres do?

Answer 9

receive and process information from receptors

Question 10

effectors examples:

Answer 10

muscles, glands

Question 11

what do effectors do?

Answer 11

bring about responses that restore optimum levels

Question 12

negative feedback is a

Answer 12

type of control mechanism

Question 13

in negative feedback:

Answer 13

• receptor detect a change in stimulus
• coordination centre compares stimulus to a set point
• effector then produces a response to correct any difference from the set point

Question 14

what does the nervous system do?

Answer 14

the nervous system enables humans to react to their surroundings and co-ordinate their behaviour

Question 15

what does the central nervous system do:

Answer 15

-co-ordinates the response of effectors

muscles contracting

Question 16

CNS:

Answer 16

brain and spinal cord

Question 17

reflex actions:

Answer 17

1) pain=stimulus-detected by surroundings
2) impulses from receptors pass along sensory neurone to CNS
3) impulse passes through a relay neurone
4) a motor neurone carries on impulse to the effector
5) the effector responds

Question 18

neurones are not..

Answer 18

directly connected to each other

Question 19

neurones communicate via..

Answer 19

synapses (gaps)

Question 20

glands:

Answer 20

produce hormones in the body

Question 21

main glands:

Answer 21

pituitary gland
thyroid gland
pancreas
adrenal gland
testis 
ovary

Question 22

pituitary gland is in the

Answer 22

brain

Question 23

thyroid gland is in the

Answer 23

throat

Question 24

pancreas is in the

Answer 24

stomach

Question 25

the endocrine system:

Answer 25

made up of glands that secrete hormones directly into the bloodstream

Question 26

hormones are..

Answer 26

chemical messengers that are carried in blood to a target organ where they produce and effect.

Question 27

how is blood glucose controlled?

Answer 27

monitored and controlled by the pancreas

Question 28

if blood glucose levels are too high:

Answer 28

- pancreases releases more insulin - insulin causes glucose move from blood into the cells - in liver and muscle cells, excess glucose is convected to glycogen for storage

Question 29

adrenaline is produced:

Answer 29

by the adrenal glands in times of fear and stress

Question 30

what does adrenaline do?

Answer 30

- increases heart rate, boosting the delivery of oxygen and glucose to the brain and muscles - prepares body to flight/fight

Question 31

thyroxine is produced in the...

Answer 31

thyroid gland

Question 32

what does thyroxine do?

Answer 32

- increases metabolic rate - controls growth and development in young animals - controlled by negative feedback

Question 33

type 1 diabetes is caused...

Answer 33

by pancreas failing to produce sufficient insulin

Question 34

type 1 diabetes results in..

Answer 34

uncontrolled high blood glucose levels

Question 35

type 2 diabetes is caused...

Answer 35

by body cells no longer responding to insulin

Question 36

type 2 diabetes risk factor:

Answer 36

obesity

Question 37

type 2 diabetes is treated..

Answer 37

with carbohydrate controlled diet and regular exercise

Question 38

sex hormones:

Answer 38

- oestrogen (female) | - testosterone (male)

Question 39

oestrogen

Answer 39

-at puberty, eggs begin to mature and be released | ovulation

Question 40

4 hormones which control menstrual cycle:

Answer 40

FSH, LH, oestrogen, progesterone

Question 41

where is FSH and LH produced

Answer 41

pituitary gland

Question 42

where is oestrogen and progesterone produced

Answer 42

ovaries

Question 43

what does FSH do

Answer 43

stimulates the maturation of eggs in the ovary | -> produce oestrogen a

Question 44

what does LH do

Answer 44

stimulates the release of the egg | ovulation

Question 45

what does oestrogen do

Answer 45

thickens uterus lining inhibits FSH release stimulates LH release

Question 46

what does progesterone do

Answer 46

maintains lining of uterus | inhibits both FSH and LH release

Question 47

how can you reduce fertility

Answer 47

variety of methods of contraception

Question 48

hormonal contraception

Answer 48

- oral contraceptives (pill) | - injection

Question 49

oral contraceptives (pill)

Answer 49

contains oestrogen and progesterone

Question 50

injection

Answer 50

slows release of progesterone to stop realise of eggs | months or years

Question 51

non hormonal contraceptives

Answer 51

- barrier methods - sterilisation - spermicidal creams - intrauterine devices (within uterus)

Question 52

increase fertility

Answer 52

FSH + LH | stimulate eggs to mature

Question 53

IVF:

Answer 53

- women get FSH +LH to stimulate growth of eggs - collect the eggs - fertilise eggs with sperm in laboratory - insert embryos into woman’s uterus