b5 - homeostasis

Question 1

define ‘homeostasis’

Answer 1

maintaining a stable internal environment

Question 2

what does homeostasis include control of?

Answer 2

• blood glucose concentration
• body temperature
• water levels

Question 3

what do our control systems include?

Answer 3

• receptors
• co ordination centres
• effectors

Question 4

define ‘receptor’

Answer 4

detect stimuli (change in environment)

Question 5

define ‘co ordination centre’

Answer 5

receives and processes information & organises a response

Question 6

define ‘effector’

Answer 6

produces a response that counteracts the change and restores the optimum level

Question 7

define ‘regulate’

Answer 7

maintaining the body’s levels

Question 8

give an example of an effector

Answer 8

muscles, glands

Question 9

Name the 2 hormones given to women during IVF treatment

Answer 9

FHS
Oestrogen

Question 10

What does FSH do in a woman’s body?

Answer 10

Triggers the growth of eggs in the ovaries and gets the eggs ready for ovulation

Question 11

what feedback is adrenaline and thryoxine?

Answer 11

negative

Question 12

what is the endocrine system?

Answer 12

glands that secrete hormones directly into the bloodstream

Question 13

explain adrenaline

Answer 13

• a hormone released by the adrenal glands
• increases heart rate
• used in stressful situations

Question 14

how does adrenaline work?

Answer 14

your brain detects stress or fear, so it sends nervous impulses to the adrenal glands, which respond by secreting adrenaline

Question 15

name the differences of hormones and nerves

Answer 15

nerves : fast
act for a short time and on a precise area

hormones : slow
act for a long time
in a more general way

Question 16

explain thyroxine

Answer 16

a hormone released by the thyroid gland
- released in the neck
- regulates basal metabolic rate

Question 17

name parts to the endocrinal system and what they do

Answer 17

pituitary gland : produces many hormones that regulate body conditions
thyroid : produces thyroxine
adrenal gland : produces adrenaline
pancreas : produces insulin
ovaries : produces oestrogen
testes : produces testosterone

Question 18

explain the menstrual cycle

Answer 18

1) uterus lining breaks down for about 4 days
2) the uterus lining builds up again into a thick, spongy layer full of blood vessels
3) an egg develops and is released = ovulation
4) wall is maintained for about 14 days until day 28

Question 19

describe the reflex arc

Answer 19

stimulus : detected by receptor
receptor : initiates electrical impulse
sensory neurone : releases a synapse
relay neurone : sends an impulse to the cns ( spinal cord, brain or pancreas )
motor neurone : sends cns response to the effector
effector : the muscle or gland
response : effector contracts, secretes a hormone that makes a response

Question 20

Describe how hormones control the menstrual cycle

Answer 20

• FSH causes an egg to mature
• FSH stimulates the release of oestrogen
• Oestrogen causes the uterus lining to thicken
• Oestrogen inhibits FSH & stimulates LH
• LH causes ovulation/ egg to be released