homeostasis

Question 1

What do control systems include

Answer 1

Cells called receptors Coordination centres Effectors

Question 2

What do receptors do

Answer 2

They detect stimuli (changes in the environment)

Question 3

What do effectors do

Answer 3

They bring about responses

Question 4

What are examples of organs that receptors are found in

Answer 4

The eyes , ears, tongue and nose, skin, brain and pancreas

Question 5

What are the eyes sensitive to

Answer 5

Light

Question 6

What are the ears sensitive to

Answer 6

Sound, and to changes in position (which enables us to keep our balance)

Question 7

What is the tongue and the nose sensitive to

Answer 7

Sensitive to chemicals (enable us to taste and smell)

Question 8

What is the skin sensitive to

Answer 8

Sensitive to touch, pressure, pain and to temperature changes

Question 9

What is the brain sensitive to

Answer 9

The brain is sensitive to blood temperature and to the concentration of water in the blood

Question 10

What is the pancreas sensitive to

Answer 10

Sensitive to the concentration of glucose in the blood

Question 11

What do coordination centres include

Answer 11

The brain, the spinal cord and the pancreas

Question 12

What are many processes coordinated by and what happens to them

Answer 12

Many processes are coordinated by chemical substances called hormones. Hormones are secreted by glands and are usually transported to their target organs by the bloodstream

Question 13

What are examples of internal conditions that are controlled

Answer 13

Temperature, the water content of the body , the ion content of the body, blood glucose levels

Question 14

When and how does water leave the body

Answer 14

Water leaves he body via the lungs when we breathe out and the skin when we sweat

Question 15

How is excess water removed

Answer 15

Excess water is removed via the kidneys in the urine

Question 16

How are urea and ions lost

Answer 16

Urea and ions are lost via the skin when we sweat.

Question 17

What happens to excess ions

Answer 17

Excess ions are removed via the kidneys in the urine

Question 18

What happens in the liver

Answer 18

-excess amino acids are deaminated to form ammonia, which is converted into urea for excretion-poisonous substances are detoxified, and the breakdown products are excreted in the urine via the kidneys.- old blood cells are broken down and the iron is stored

Question 19

What happens in a healthy Kidney

Answer 19

• the blood is filtered - all the glucose is reabsorbed - the dissolved ions needed by the body are reabsorbed - as much water as the body needs is reabsorbed- urea, excess ions and excess water are released as urine

Question 20

What happens if the water content of the blood is too low

Answer 20

If the water content of the blood is too low, the pituitary gland releases a hormone called ADH into the blood. This causes the kidneys to reabsorbed more water and results in a more concentrated urine

Question 21

What happens if the water content of the blood is too high

Answer 21

If the water content of the blood is too high, less ADH is released into the blood. Less water is reabsorbed in the kidneys resulting in a more dilute urine

Question 22

What is the body temperature monitored and controlled by

Answer 22

Body temperature is monitored and controlled by the thermoregulatory centre in the brain. This centre has receptors sensitive to the temperature of the blood flowing through the brain

Question 23

What do temperature receptors in the skin do

Answer 23

Temperature receptors in he skin send impulses to he thermoregulatory centre, giving in informations about skin temperature

Question 24

What happens if the core body temperature is too high

Answer 24

• blood vessels supplying the skin capillaries dilate so that more blood flows through the capillaries and more heat is lost- sweat glands release more sweat, which cools the body as it evaporates

Question 25

How does sweating help to cool the body

Answer 25

Sweat increases heat loss by evaporation More water is lost when it is hot , and more fluid has to be taken through a drink or food to balance this loss

Question 26

What happens if the core body temperature is too low

Answer 26

- blood vessels supplying the skin capillaries construct to reduce the flow of blood through the capillaries - muscles may 'shiver' - their contraction needs respiration , which releases some energy to warm the body

Question 27

What may people suffering from kidney failure be treated by and what does it do

Answer 27

People who suffer from kidney failure may be treated by organ transplant or by using kidney dialysis, which restores the concentrations of dissolved substances in the blood to normal levels

Question 28

What happens in dialysis

Answer 28

In a dialysis machine a persons blood flows between partially permeable membranes.The dialysis fluid contains the same concentration of useful substances as the blood of a person without Kinsey diseaseThis ensures that glucose and useful mineral ions are not lost but that harmful substances such as urea pas out from the blood into dialysis fluid

Question 29

Advantages of treating organ failure by mechanical devices or transplant

Answer 29

Artificial organs can replace diseased or damaged organs thereby providing the ailing patient with an opportunity to lead a healthy and normal life

Question 30

Disadvantages of treating organ failure by mechanical devices or transplant

Answer 30

There are high chances of organ failure, and the body may take sometime to adapt to the new organ There are some ethical issues, for example in the case of smoking , people may not take the consequences seriously, and go for artificial organ therapy instead of avoiding nicotine

Question 31

What keeps conditions in the body relatively constant

Answer 31

Automatic control systems

Question 32

What is an advantage of dialysis

Answer 32

IMMEDIATE TREATMENTMachines usually available No problems with tissue matchingNo need for surgery

Question 33

Disadvantages of dialysis

Answer 33

INCONVENIENThas to happen at regular intervals at least twice a weekExpensive in long termHave to watch a very strict dietSubstances build up inbetween sessions - symptoms show againRisk of blood clots (-> DVT/ heart attack) Anticoagulant drugs (-> excessive bleeding)

Question 34

Advantages of kidney transplant

Answer 34

LONG TERM / permanent solutionNo special dietNo sessions of dialysisRelatively inexpensive after surgeryKidney works all of the time (no symptoms)

Question 35

Disadvantages of kidney transplant

Answer 35

Need donor (often not available)Need tissue match (risk of rejection)Have to take immunosuppressant drugs (increased risk of infection)Risk of surgeryDanger of infectionSurgery every 10 years (risk/cost)

Question 36

What is the blood glucose monitored and controlled by

Answer 36

The pancreas

Question 37

Much of the glucose is stored as ....... In ..........And what happens when these stores are full

Answer 37

Much of the glucose is stored as glycogen in the liver and muscles When these stores are full, excess glucose is stored as lipid

Question 38

What happens if the blood glucose levels are too big

Answer 38

The pancreas produces the hormone insulin, which allowed the glucose to move from the blood into the cells

Question 39

What happens when the blood glucose levels fall

Answer 39

The pancreas produces a second hormone, glucagon. This causes the glycogen to be converted into glucose and released into the blood

Question 40

What happens in type 1 diabetes

Answer 40

A persons blood glucose level may be too high because the pancreas does not produce enough of the hormone insulin

Question 41

What can type 1 diabetes be controlled by

Answer 41

Careful diet , exercise , and by injecting insulin

Question 42

What happens in type 2 diabetes

Answer 42

Type 2 diabetes develops when the body does not respond to its own insulin. Obesity is a significant factor in the development of type 2 diabetes

Question 43

What can type 2 diabetes be controlled by

Answer 43

Careful diet , exercise and by drugs that help the cells to respond to insulin