Homeostasis test questions

Question 1

why does the temperature near the brain decrease once cold water is drunk?

Answer 1

-blood is cooled at mouth
-cooled blood flows to brain

Question 2

blood enters the kidney through the process of…

Answer 2

filtration

Question 3

why is glucose not found in urine

Answer 3

-reabsorbtion

Question 4

what are the advantages and disadvantages of having a kidney transplant instead of having dialysis

Answer 4

-there is a risk of infection from the surgery
-kidney transplant is cheaper long term
-kidney transplant may be rejected
-there is no need to control diet

Question 5

why does the body need to lose water from skin?

Answer 5

-to maintain body temperature

Question 6

how does sweating help control body temperature?

Answer 6

-by cooling us down

Question 7

describe how the body responds when a decrease in core body temperature is detected

Answer 7

-blood vessels supplying skin constrict
-less blood flows to capillaries so less energy is lost
-muscles contract and relax rapidly
-releasing energy

Question 8

describe how a woman’s nervous system coordinates the reflex action

Answer 8

-the stimulus is detected by the receptors in the skin of hand
-electrical impulses pass along the sensory neurones
-impulses pass from the sensory neurones to the relay neurones in the central nervous system
-the electrical impulse passes from the relay neurones to the motor neurones
-there is a synapse between neurones where chemical crosses
gap
-synapses are in the spinal cord
-the electrical impulse then passes along the motor neurones to the effector which is a muscle that contracts

Question 9

describe how hormones control the mentsrual cycle

Answer 9

-FSH causes the maturation of eggs in the ovaries
-LH stimulates the release of the egg from the ovaries
-both progesterone and oestrogen maintain the lining of the uterus
-oestrogen causes the uterus lining to grow
-oestrogen inhibits the release of FSH and stimulates the release of LH
-progesterone inhibits FSH and LH production

Question 10

name the common defect of the eye which causes distant objects to appear out of focus

Answer 10

-myopia ( short-sightedness)

Question 11

describe how the brain receives information about light entering the eye

Answer 11

-light is detected the retina which sends the electrical impulse along sensory neurones to the brain along the optic nerve

Question 12

A man has used up his supply of drinking water
-explain how ADH and the kidneys reduce water loss (3)

Answer 12

-the blood becomes too concentrated so the hormone ADH is released by the pituitary gland
-leads to increased permeability of kidney tubules
-more water is taken back into the blood

Question 13

Explain why a person with type 2 diabetes often has a higher blood insulin concentration than a non-diabetic person

Answer 13

-cells absorb less glucose
-glucose concentration in blood remains high

Question 14

explain why more water was lost breathing during a race?

Answer 14

-more energy needed
-more aerobic respiration
-increased breathing rate

Question 15

what is a hormone

Answer 15

a chemical messenger made by the endocrine system to affect a specific target organ

Question 16

plan an investigation to show the effect of light from one direction on the growth of plant seedlings

Answer 16

• several seedlings in each batch or one pot of seedlings in each
  batch
• measure heights of shoots
• leave some in dark with light from one side / direction in box
  with hole
• control(s) with all-round light or rotating on clinostat or in dark
• control variable(s) e.g. same temperature / water / soil type
• after suitable time (at least several hours)
• record appearance of seedlings re. light direction
• re-measure heights of shoots
  -* calculate mean height increase for each group