Homeostasis and Response

Question 1

How does a woman’s hand unconsciously move away when she touches a hot stove? use the nervous system in your answer.

Answer 1

1: Receptors in hand feel change in temperature ( stimulus )
2:Electrical signal is transmitted along a sensory neuron
3: Neurotransmitters diffuse across synapse to relay neuron in the spinal cord
4: motor neuron transmits an electrical impulse to a muscle effector
5:muscle effector contracts muscles to pull hands away

Question 2

How do neurotransmitters get across the synapse?

Answer 2

They diffuse from the presynaptic neuron to the postsynaptic neuron.

Question 3

How should we measure reaction time?

Answer 3

1: The person being tested sits with arm rested on table
2: Hold ruler in between their thumb and forefinger
3: Let go of ruler without giving warning
4: person should catch ruler as quickly as they can
5: repeat the test several times and then calculate the mean distance it fell
6: person being tested should then drink caffeinated drink, after ten minutes repeat steps 1-5

Question 4

What is the purpose for the cerebral cortex

Answer 4

Its responsible for things like consciousness, intelligence, memory and language.

Question 5

What is the purpose of the medulla?

Answer 5

Controls unconscious activities like breathing and your heart beat.

Question 6

What is the purpose of the cerebellum?

Answer 6

Responsible for muscle coordination.

Question 7

What is the Sclera?

Answer 7

The tough supporting wall of the eye.

Question 8

What is the Cornea?

Answer 8

The transparent outer layer found at the front of the eye. Refracts light in to the eye.

Question 9

What is the iris?

Answer 9

contains muscles that allow it to control the diameter of the pupil and therefore how much light comes in to the eye.

Question 10

What is the lens?

Answer 10

The lens focuses light on to the retina ( which contains receptor cells sensitive to light intensity and colour)

Question 11

What does the optic nerve do?

Answer 11

The optic nerve carries impulses from the receptors on the retina to the brain.

Question 12

How do muscles in the eye respond to near or far objects?

Answer 12

Near - Ciliary muscles contract, which slackens the suspensory ligaments
Far - the ciliary muscles relax and suspensory ligaments tighten

Question 13

What is the medical term for long sightedness?

Answer 13

Hyperopia

Question 14

What is the medical term for short sightedness

Answer 14

Myopia

Question 15

How is temperature in the body controlled?

Answer 15

Through negative feedback

Question 16

What does the thermoregulatory centre do?

Answer 16

Acts as a coordination centre - receives info from temperature receptors and triggers effectors immediately

Question 17

What are all the different endocrine glands in the body and where are they in the body?

Answer 17

Pituitary gland - brain
Thyroid - throat
Adrenal - on top of kidneys
Ovaries (female only) - Crotch
Testes (Males only) - Crotch
Pancreas - next to kidneys

Question 18

What are the differences between the endocrine and nervous systems?

Answer 18

Endocrine
- Slower
- Act for extended period of time
- Act more generally on large parts of the body
- Chemical messengers sent through bloodstream

Nervous
- Very fast action
- Acts for short time
- Acts on precise area

Question 19

What are the four different hormones involved in the menstrual cycle

Answer 19

1: FSH
2: Oestrogen
3:LH
4:Progesterone

Question 20

What are the advantages and disadvantages of dialysis?

Answer 20

Advantage:
- Dialysis can buy time for a patient with kidney failure until donor can be found
- Useful dissolved ions and glucose wont be lost from the blood during dialysis
Disadvantage:
- Short term solution
- Lot of time put in to the procedure
- May cause blood clots and infections
- Expensive to run for the NHS

Question 21

How does the negative feedback system respond to a high water content?

Answer 21

• A receptor in brain detects water content is too high
• The coordination centre in the brain receives the info and coordinates a response
• Pituitary gland releases less ADH, so less water is reabsorbed from the kidney tubules

Question 22

How does the negative feedback system respond to a low water content?

Answer 22

• A receptor in the brain detects that the water content is too low
• The coordination centre in brain receives info and coordinates a response
• The pituitary gland releases more ADH, so more water is reabsorbed from the kidney tubules

Question 23

What are the advantages and disadvantages of a kidney transplant?

Answer 23

Advantages:
- Only cure for kidney failure is to have a kidney transplant
- Transplants are cheaper for the NHS in the long term
- Longer term solution for kidney failure compared to dialysis
Disadvantage:
- Risk of infection from surgery
- Risk of rejection to host body
- Long waiting list for donor

Question 24

What are the three substances removed from the body in the form of urine?

Answer 24

• Water
• Urea
• Ions

Question 25

How does the negative feedback system respond to a high body temp?

Answer 25

- Temp. receptors detect a core body temperature that is too high - The TRC acts as a coordination centre, it receives info from the temp. receptors and triggers the effectors automatically - Effectors, produce a response to counteract change

Question 26

How does the negative feedback system respond to a low body temp.?

Answer 26

- Temperature receptors detect a core body temperature that is too low - The thermoregulatory centre acts a coordination centre, it receives info from the temp. receptors and triggers the effectors automatically - Effectors produce a response and counteract the change

Question 27

What are the effector responses for a high body temp. ?

Answer 27

- Hairs lie flat - Sweat is produced by sweat glands and evaporates from the skin, giving energy to the enviroment - The blood vessels supplying the skin dilate so more blood flows close to the surface of the skin, transferring thermal energy by radiation to the enviroment

Question 28

What are the effector responses for a low body temp. ?

Answer 28

- Hair stands up to trap insulating layer of air - No sweat is produced - blood vessels close to the skin constrict - Shivering starts which creates heat by causing more respiration, which is an exothermic reaction

Question 29

What are secondary sex characteristics for men?

Answer 29

- Deepening of voice - Growing of pubic hair

Question 30

Describe how hormones describe the menstrual cycle

Answer 30

1: FSH released from pituitary and stimulates maturation of egg 2: Oestrogen inhibits FSH production and stimulates LH production 3: LH stimulates ovulation 4: Progesterone inhibits FSH and LH production Oestrogen and progesterone maintain uterus lining

Question 31

How are low water concentration levels responded to by the pituitary gland and the kidneys?

Answer 31

1: Low water concentration is detected 2: Low concentration of water causes more ADH to be released 3: Therefore more water is reabsorbed as ADH causes higher permeability of entrance to kidneys