Transport In Humans

Question 2

Describe diffusion in unicellular organisms

Answer 2

-Small organist have no problem absorbing oxygen because their surface area is big enough to gain sufficient oxygen for it’s small volume of cells by diffusion
-No transport system required because gases can diffuse directly into all tissues because of high surface area to volume ratio
-Whole cell surface in contact with the environment

Question 3

Describe diffusion in multicellular organisms

Answer 3

-large organisms (humans)have a relatively small surface area when compared with their large volume of cells
-slow rate of diffusion
-only outer cells are in contact with the environment, inner cells have no contact with the environment
-therefore large organisms have adaptations to increase their surface area

Question 4

What are the adaptations to increase surface area in large multicellular organisms?

Answer 4

-to compensate we have lungs
-circulatory system which will transport nutrients around the body
-alveoli have large surface area for gas exchange as they are bumpy and there is lots of them
-root hair cells in plants for absorption of nutrients from the soil
-small intestine as it’s long and contains vili in its lining to absorb small food molecules

Question 5

What are the 4 components of blood?

Answer 5

RBC
WBC
platelets
plasma

Question 6

What is the structure and function of the RBC?

Answer 6

Structure
-biconcave shape for large surface area
-produced in bone marrow
Function
-bonds with haemoglobin and carries oxygen around the body

Question 7

What is the function of the WBC?

Answer 7

To defend the body against infections by identifying, attacking and destroying harmful pathogens such as bacteria and viruses

Question 8

What is the structure and the function of platelets?

Answer 8

Structure
-shape of a plate
-no nucleus
Function
-helps with blood clotting and forming scabs
-prevents/stops bleeding

Question 9

What is the structure and the function of plasma?

Answer 9

Structure
-contains 91-92% water and 8-9% solids
Function
Helps to recover your body from injury, distribute nutrients, remove waste and prevent infection

Question 10

How does phagocytes respond to disease?

Answer 10

Phagocytes- immune cells
That surround and kill microorganism, and also protects the body from foreign particles, bacteria by ingesting harmful cells
They ingest and digest the pathogens using digestive enzymes in a process called phagocytosis

Question 11

How does lymphocytes respond to disease?

Answer 11

-produce antibodies in response to antigens on the surface of the pathogen
-antibodies are complementary in shape to the antigens
-antibodies work in 3 ways
1. Cause pathogens to stick together
2. Mark them for destruction
3. Act as antitoxins

Question 13

What is an antigen?

Answer 13

Proteins on the surface of pathogens, these allow human body to identify pathogens as foreign and trigger an immune response

Question 14

What is vaccination?

Answer 14

Process by which out body creates defence or antibodies to fight pathogens by purposely being exposed to a non-threatening inactive or dead version of the pathogen (attenuated pathogen which is unlikely to cause harm) but it still contains the same antigen as the actual pathogen which triggers a primary immune response

Question 15

Explains vaccination

Answer 15

1. You are injected with a vaccine with a small amount of dead or inactive pathogen which still have the same antigen
2. Which blood cells detect the antigens
3. White blood cells make antibodies to fit the antigens
4. The antibodies attach themselves to the inactive pathogens and kill them, aka primary immune response
5. White blood cells recognise the shape of the antigen
6. Live pathogen enter the body for the first time (infection)
7. White blood cells instantly recognise the live pathogens as the have the same antigens as the vaccine and make antibodies immediately - secondary immune response
8. The antibodies attach themselves and kill the pathogens before they have a chance to make you feel ill, no symptoms

Question 16

Why does heart rate increases during exercise?

Answer 16

-more muscle contraction
-more energy needed
-more O2 and glucose
-more blood flow
-more removal of waste products
Which therefore increases the heart rate

Question 17

What are the 6 risk factors that can cause the coronary heart disease?

Answer 17

Genetics
High blood pressure
Fatty food
Smoking
Stress
No exercise

Question 18

Explains how genetics can be a risk factors that for CHD

Answer 18

More likely to have CHD is your parent have it

Question 19

Explains how high blood pressure can be a risk factors that for CHD

Answer 19

Can cause damage to the heart and arteries

Question 20

Explains how fatty food can be a risk factors that for CHD

Answer 20

Fat can built up in the blood vessels

Question 21

Explains how smoking can be a risk factors that for CHD

Answer 21

Raising blood pressure which can cause blood clots
Increase heart rate

Question 22

Explains how stress can be a risk factors that for CHD

Answer 22

Raises blood pressure

Question 23

Explains how no exercise can be a risk factors that for CHD

Answer 23

Regular exercise reduces blood pressure and strengthen the heart

Question 24

Describe arteries

Answer 24

-going towards the body, away from the heart
- carries oxygenated blood to the body tissues
-high blood pressure
-elastic walls
-narrow lumen
-no valves

Question 25

Describe veins

Answer 25

-towards the heart, away from the body -carries deoxygenated blood from the body tissues -low blood pressure -smooth inner lining -wide lumen -valves to prevent the back flow of blood

Question 26

Describe capillaries

Answer 26

-from arteries to veins - exchanges substances -low blood pressure -one cell thick -lumen wide enough for one RBC at a time

Question 28

What are the effects of smoking in terms of the circulatory system?

Answer 28

The carbon monoxide in cigarette smoke reduces the amount of oxygen the blood can carry, to make up for this, heart rate increases which leads to an increase in blood pressure High blood pressure damages the artery walls, making the formation of blood clots more likely It also increases the risk of CHD

Question 29

What are the effects of adrenaline on the heart rate?

Answer 29

Secreted by the adrenal glands Fight of flight - more blood to muscles to supply oxygen and glucose for aerobic respiration