Topic 10 - Exchange and Transport in Animals Flashcards
1
Q
why are exchange systems so important in living organisms?
A
- they are vital as they allow the transfer of essential substances in and out of cells ( reactants and waste products )
2
Q
SA : V ratio
A
- the higher the SA : V ratio, the more efficiently organisms can exchange substances with its’ environment
3
Q
why are exchange surfaces needed in complex organisms?
A
- they have a smaller SA : V which makes it more difficult to exchange enough substances
- to supply their entire volume across their outside surface alone.
4
Q
what else is needed apart from exchange system
A
- exchange surfaces gives efficient diffusion and needs a transport system to move substances between the exchange surface and rest of the body
5
Q
which 3 factors affect the rate of diffusion?
A
1) surface area
2) concentration gradient
3) diffusion distance
6
Q
surface area
A
- the higher the SA, the faster the rate of diffusion
- more surface available for molecules to move across. they move faster from one side to the other
7
Q
concentration gradient
A
- higher concentration gradient = faster rate of diffusion
- bigger difference of concentration of molecules between two areas
8
Q
diffusion distance
A
- the larger the diffusion distance, the slower the rate of diffusion
- thinner the cell membrane of the exchange surface, the shorter distance the molecules have to move
9
Q
Fick’s Law
A
rate of diffusion ∝ (SA x concentration gradient) / diffusion distance
10
Q
alveoli
A
- air sacs at the end of bronchioles
- site of gas exchange
11
Q
how does the gas exchange work
A
- networks of blood vessels ( capillaries) surround the alveoli
- gases diffuse between the air in the alveoli and blood in the capillaries
12
Q
how is the concentration gradient in the exchange surface maintained
A
- blood constantly flows and supplied to capillary taking O2 away and bringing more CO2.
- blood arriving at alveoli has just returned to the lungs so contains lot of CO2 and very small amnt of O2
- higher concentration of CO2 in capillaries, higher concentration of O2 in alveoli.
13
Q
SA
A
- collectively all the alveoli have a massive surface area
14
Q
diffusion distance
A
- very thin walls between alveoli and capillaries so shorter diffusion pathway which leads to higher rate
15
Q
moist lining
A
- dissolves gases so they can diffuse through the alveolar walls
16
Q
purpose of circulatory system
A
- delivers useful substances to every cell in the body
- carries waste substances to where they can be removed from the body
17
Q
blood
A
- tissue that transports blood around the body
18
Q
main components of blood
A
- RBC
- WBC
- platelets
- plasma
19
Q
red blood cells ( ERYTHROCYTES ) purpose and structural adaptions
A
- transports oxygen around the body
- bi concave shape to absorb more oxygen
- no nucleus so they can store more haemoglobin to carry more oxygen
20
Q
oxyhaemoglobin
A
- in the lungs, oxygen diffuses into the blood
- oxygen combines with haemoglobin to form oxyhaemoglobin
- in body cells reverse happens, splits up and releases oxygen into the cells
21
Q
WBC
A
- defends against microorganisms that cause disease
- phagocytes : engulf pathogens
- b lymphocytes : produces antibodies against microorganisms and antitoxins
22
Q
platelets
A
- small fragments of cells that help the blood to clot at a wound
- they seal the wound and stops you from losing too much blood and stops microorganisms from getting in
23
Q
plasma
A
- pale straw-coloured liquid that is the liquid component of blood
- dissolves all the components and makes the blood liquid so it can flow
24
Q
blood vessels
A
- ## they transport the blood throughout the body
25
Q
arteries function
A
- carry blood away from the heart at high pressure
- normally carries blood rich in O2 and low in CO2
26
Q
arteries structural adaptions
A
- relatively small lumen compared to walls, to maintain high pressure
- walls have thick layers of muscle to make them thick to withstand
- rings of smooth muscles and elastic fibres allow them to constrict or dilate depending on body’s needs
27
Q
veins function
A
- carry blood to the heart
- mostly carry blood high in CO2 and low in O2
28
Q
veins structural adaptions
A
- blood at lower pressure so walls don’t need to be as thick as artery walls
- veins have a relatively large lumen to make the blood flow despite low pressure
- valves to keep blood flowing in right direction and prevent backflow
29
Q
capillaries functions
A
- arteries branch into capillaries and capillaries join up to form veins
- they carry blood very close to each cell in body to exchange substances
30
Q
capillaries structural adaptions
A
- permeable walls so substances can diffuse in and out
- walls very thin ( 1 cell ) : increases rate of diffusion as shorter diffusion pathway
- very narrow so can squeeze into gaps between cells. large SA : v ratio
31
Q
double circulatory system (1st circuit)
A
- 1st circuit : heart pumps deoxygenated blood to the lungs to take in oxygen and the oxygenated blood returns to heart
32
Q
double circulatory system (2nd circuit)
A
- 2nd circuit : heart pumps oxygenated blood around the body. blood gives up its oxygen and deoxygenated blood returns to the heart
33
Q
4 chambers of heart
A
- right atrium
- right ventricle
- left atrium
- left ventricle
34
Q
blood vessels leading in and out of these chambers
A
- vena cava
- pulmonary artery
- pulmonary vein
- aorta
35
Q
blood flow through the heart ( P1)
A
- deoxygenated blood flows through the right side of the heart and
- oxygenated blood flows through the left side of the heart
36
Q
blood flow through the heart ( P2)
A
- right atrium of heart receives deoxygenated blood from vena cava
- left atrium receives oxygenated blood from pulmonary vein
- atria contract at the same time, forcing the tricuspid and bicuspid valves open and pushing blood into ventricles
37
Q
blood flow through the heart ( P2)
A
- tricuspid and bicuspid valves close
- ventricles contract at same time, pushing deoxygenated blood out of the right ventricle to the lungs via the pulmonary artery
- pushing oxygenated blood out of the left ventricle to the rest of body via aorta
38
Q
thickness of atrium walls
A
- relatively thin as only need to pump blood a short distance to ventricles so don’t require much muscle
39
Q
thickness of ventricle walls
A
- ventricles walls are relatively thick as they need to pump blood further distances
40
Q
left ventricle vs right ventricle
A
- left ventricle wall much thicker as it needs to pump blood much larger distance around whole body
- right ventricle only needs to pump it to lungs
41
Q
cardiac output
A
heart rate x stroke volume
42
Q
A
