Maimting Internal Environemtns

Question 1

What is homeostasis

Answer 1

Regulation of a cell or organism in order to maintain optimum conditions for function in response to internal and external factors

Question 2

What role does the hypothalamus play in homoeostasis

Answer 2

The hypothalamus is the main part that detects and regulates all of the bodily things and metabolism

Question 3

What does you body do when the core temparature decreases

Answer 3

• vasoconstriction
• hair strands stand up
• shivering
• no sweat

Question 4

What is vasoconstriction

Answer 4

Vasoconstriction is the narrowing of blood vessels to reduce blood flow to skin, helping to conserve heat.

Question 5

What does the hair standing up do

Answer 5

Helps trap a layer of air between the stands, acting as an insulating layer.

Question 6

How does shivering help with warming you up

Answer 6

• Shivering requires energy
• Energy is transferred through respiration
• Respiration is an exothermic reaction meaning it releases energy in the form of heat to its surroundings

Question 7

What things does your body do to decrease core body temperature

Answer 7

• more sweating
• vasoconstriction
• hair lies flat

Question 8

What does vasodilation do

Answer 8

Vasodilation is the widening of blood vessels to increase blood flow to the skin, helping to release heat

Question 9

What does sweating do

Answer 9

When sweat is on your skin and the wind blows the heat is drawn from the sweat cooling you down

Question 10

What are external factors that affect blood sugar levels

Answer 10

• eating
• excersise
• metabolism

Question 11

Which organ monitors glucose levels

Answer 11

Pancreas

Question 12

What does the body do when blood glucose levels are too high

Answer 12

The pancreas secretes insulin into the blood stream

Question 13

What does insulin do

Answer 13

It converts glucose into glycogen, making it easier to store and builds up as fat

Question 14

What does the body do when blood sugar levels are low

Answer 14

Glucagon is secreted into the blood stream by the pancreas, and it reconverts glycogen into glucose

Question 15

What does glucagon do

Answer 15

In the liver, the glucagon converts glycogen back into glucose which increases the blood sugar level

Question 16

What happens when you have type 1 diabetes

Answer 16

The immune system has attacked the hormone producing cells in the pancreas
This means that the pancreas cannot produce insulin or glucagon

Question 17

What is the problem with type two diabetics

Answer 17

Type two diabetes CAN produce insulin/glucagon, however:
- they do not release enough for the amount of sugars in their bloodstream
- their cells no longer respond to insulin and are resistant

Question 18

Is type one diabetes genetic

Answer 18

It can be dependant in genetic but the exact cause is unknown

Question 19

Is type 2 diabetes genetic

Answer 19

Yes as if your family has type 2 them you at a risk of it HOWEBER external factors can also come into play

Question 20

How do people with type one diabetes manage

Answer 20

They mange their diabetes with an insulin pump combined with continuous blood monitoring system

Question 21

What happens to the cells when water level is too high in the blood

Answer 21

Water enters the cell by osmosis and makes it hypertonic causing it to swell and may burst

The blood becomes too thick, leading to blood clots

Question 22

What happens to the cells if blood is too thin

Answer 22

the blood becomes hypertonic, meaning water enters the cells, causing them to swell and may even burst

Question 23

What is the role of ADH

Answer 23

ADH is able to control the permeability of the tubules in the kidneys
This helps control how much or how little water is absorbed into the blood stream

Question 24

What does the body do when there is low water concentration in the blood (control mechanism)

Answer 24

• hypothalamus detects low blood water concentration
• pituitary gland produced more ADH
• kidneys resorb more water into the tubules
• less volume of urine produced and more water in blood stream

Question 25

What happens to the body when there is increased salt concentration in the blood

Answer 25

- the blood is hypotonic - thirst response takes place - less urine produced as a result of this

Question 26

What happens when there is less salt in the blood

Answer 26

-> lysis / hypertonic blood -> water moves into cells. Cells burst -> high volume of urine

Question 27

Urine produced after vigorous exercise is often much darker in colour than urine produced when at rest. Which reason explains why urine becomes darker in colour?

Answer 27

Increased sweating and increased ADH production.

Question 28

After the alcohol has been removed from person A’s body, control mechanisms will correct the excess loss of water caused by the alcohol. Describe these control mechanisms.

Answer 28

-> hypothalamus detects low water levels -> this leads to an increase in ADH levels -> increased permeability of tubules -> less urine produced, less sweating

Question 29

Red blood cells burst when they are placed in a solution with a much higher water potential than the red blood cells themselves. This is called lysis. Explain why lysis happens.

Answer 29

-> during lysis water moves into cells via OSMOSIS from an area of high water potential to low water potential -> lots of water moved into cells causing pressure against the CELL MEMBRANE -> this causes the cell membrane to rupture and burst

Question 30

What is the main proof of type 2 diabetes (use graph in Maintaing internal environments H)

Answer 30

-> there is too much or too little insulin produced -> low ability to control insulin levels

Question 31

The hormone ADH affects the permeability of part of the kidney tubule. Name the part of the tubule affected by ADH.

Answer 31

Collecting duct

Question 32

What evidence is there to suggest that selective reabsorption occurs in the kidney tubule?

Answer 32

-> originally the filtrate contains high amounts of glucose, but there is no glucose in the urine -> the filtrate also originally contains a lot of salt, but in the urine there is lower amount of salt -> the filtrate also contains a high level of urea, which is all left behind, and is the most present in the urine -> other substances are still almost present int urine

Question 33

To lower the blood pressure, a drug can be taken to increase the amount of water excreted by the body. Which organ would be targeted by the drug and what effect would it have on the urine?

Answer 33

The organ is the kidney Effect on urine : much more dilute urine

Question 34

If ADH levels rise, how will this affect urine? (1 mark)

Answer 34

Higher concentration of urea

Question 35

Probash is ill and is having tests in hospital. His doctors monitor his body temperature frequently. Explain why it is important to monitor Probash's body temperature frequently (2 marks)

Answer 35

To make sure that his enzymes don’t go beyond their optimal temperature and denature

Question 36

Person A’s input of water is 2700ml, but their output is 2900ml Why do they need treatment for their kidneys

Answer 36

They are loosing more water from the kidneys than is being taken in

Question 37

Explain why overheating of the body may stop chemical reactions in cells.

Answer 37

Enzymes work at an optimal temperature An increase in temp will cause them to denature, changing the shape of they active site This means that the substrate will be unable to bond with the enzyme The reaction is no longer catalysed

Question 38

Urine produced after vigorous exercise is often much darker in colour than urine produced when at rest. Which reason explains why urine becomes darker in colour

Answer 38

Increased sweating and increased ADH production.

Question 39

What can be used to treat type 2 diabetes but not type 1?

Answer 39

Diet and excersise

Question 40

Explain the affects of alcohol in the body

Answer 40

-> less ADH released in the body / ADH suppressed -> less reabsorption of water into the bloodstream / more water excreted out of the body

Question 41

After the alcohol has been removed from a persons body, control mechanisms will correct the excess loss of water caused by the alcohol. Describe these control mechanisms.

Answer 41

-> hypothalamus will detect low water levels in the blood -> leads to increased ADH levels being produced -> this increases the permeability of the tubules -> less water in urine meaning overall less volume of urine produced and more absorbed into blood stream

Question 42

Scientists are using human embryonic stem cells to grow cells to treat type 1 diabetes. Explain why scientists use embryonic rather than adult stem cells.

Answer 42

-> embryonic stem cells differenciate into more types of cells than adult ones -> therefore insulin producing cells are easier to develop