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A Level Biology Y1 > Transport in Animals > Flashcards

Transport in Animals Flashcards

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1
Q

What are the atria?

A

Thin muscular walls receiving (low pressure) blood returning to the heart in veins

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2
Q

What are ventricles?

A

thick muscular walls contract to move blood (at high pressure) into arteries

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2
Q

What does the right ventricle do?

A

contracts to move deoxygenated blood from the right atrium to the pulmonary artery

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3
Q

What does the left atrium do?

A

receives oxygenated blood via the pulmonary veins

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3
Q

What does the right atrium do?

A

Receives deoxygenated blood via the vena cava

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4
Q

What does the left ventricle do?

A

contract to move oxygenated blood into the aorta

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4
Q

What does the left atrium do?

A

receives oxygenated blood via the pulmonary veins

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5
Q

describe the function of the arteries?

A

-carries blood away from the heart

-elastic tissue in the aorta stretches when the left ventricle contracts

-when left ventricle relaxes the artery wall recoils due to its elasticity and forces blood to body tissues

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5
Q

Which ventricle has a thicker wall and why?

A

The left ventricle has a much thicker muscular wall as it has to pump oxygenated blood towards the rest of the body. (right ventricle only supplies the lungs)

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5
Q

Function of veins?

A
  • carry blood under low pressure towards the heart
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5
Q

Features of arteries

A
  • Blood is carried under higher pressure than veins
  • do not posses valves except for the aorta and pulmonary artery
  • thicker wall and smaller lumen than veins + more elastic fibres and smooth muscle fibres
  • carry oxygenated blood except for the pulmonary arteries
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6
Q

What is the function of tendinous cords?

A

prevents valves turn inside out when ventricle contracts

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6
Q

what are AV and Semi-lunar valves?

A

AV (atrioventricular) valves - between atrium and ventricles

Semi-lunar valves - between ventricles and arteries

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6
Q

How to work out Cardiac Output?

A

stroke volume (cm^3) x heart rate (min^-1)

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7
Q

Why don’t arterioles have to withstand the very high pressure found in main arteries?

A
  • they posses a higher proportion of smooth muscle than elastic fibres and so can control the flow of the blood to different tissues or relaxation of the smooth muscle in their walls
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7
Q

What is vasoconstriction and vasodilation?

A

Vasoconstriction - the contraction of smooth muscle causes narrowing of the arterioles reducing blood flow to the capillaries

Vasodilation - the relaxation of smooth muscle that causes widening of the arterioles increasing blood flow to the capillaries

7
Q

Features of veins?

A
  • thinner walls than arteries
  • less elastic fibres and smooth muscles than arteries
  • larger lumen than in arteries so even at low pressure the blood flows back to the heart at the same rate that it leaves the heart
7
Q

What is venous return?

A
  • skeletal muscles that surround veins contracting and compressing the veins pushing the blood along
7
Q

what is the function of the capillaries?

A

to exchange of materials such as oxygen & carbon dioxide between the blood and body cells.

8
Q

what is haemoglobin made up of?

A

4 haem units and 4 polypeptide chains ( quaternary protein structure)

  • each haem unit can combine with one oxygen molecule so one Hb molecule can transport 4 oxygen molecules
8
Q

describe the features of the capillaries? (6)

A

one endothelial cell thick- short diff pathway

gaps between endothelial cells (fenestrations) - increase permeability

many capillaries/highly branched - large surface area

high total cross-sectional area=more frictional resistance=slower blood flow which allows more time for substance exchange

small diameter means RBC’s are squeezed against the endothelial wall - short diff pathway

8
Q

differences between tissue fluid and lymph

A
  • TF contains less WBC’s than lymph
8
Q

Describe the process of the formation of tissue fluid

A
  • at arteriole end of capillary the hydrostatic pressure of the blood plasma is much higher than the osmotic pressure of the tissue fluid so water and small molecules osmose into and forms the tissue fluid
  • plasma protein and blood cells stay in the capillary
  • loss of fluid and high frictional resistance reduces blood pressure
  • the large plasma proteins which remain in the blood reduce the water potential of the blood plasma causing the osmotic uptake of water into the capillaries
  • less hydrostatic pressure at the venule end of the capillary means that due to the osmotic pressure of the tissue fluid some of the water is reabsorbed by osmosis
9
Q

equation for oxyhaemoglobin?

A

Hb + 4O2 ⇌ Hb(O2)4

9
Q

what is lymph + why does it form?

A
  • this process is too slow to re-absorb all the filtered plasma and some of the tissue fluid enters ;lymph capillaries
  • this tissue fluid is now called lymph which eventually return to the blood when the lymph capillaries join to form lymph vessels
10
Q

differences between tissue fluid and blood plasma

A
  • TF contains no large plasma proteins
  • TF contains more CO2 than blood plasma
10
Q

what is haemoglobin?

A

An iron containing pigment, which loosely and reversibly combines with oxygen to form oxyhaemoglobin

11
Q

what is the oxyhaemoglobin dissociation curve

A

a graph showing the relationship between the partial pressure O2 and percentage saturation of haemoglobin

normally an S shape

12
Q

Describe the Loading, transport and unloading of oxygen (3)

A
  • deoxygenated blood enters the lung capillaries
  • alveoli contain a high conc of oxygen = conc gradient for diffusion of O2
  • O2 enters RBC and combines with Hb to form OxyHb
13
Q

what is the Bohr effect

A

-increased respiration = more CO2 which dissolves into the blood and lowers the pH (carbonic acid)

  • this changes the quaternary structure of Hb and lowers its affinity for O2 and shifts the curve to the right
13
Q

why is the HbO2 dissociation curve an S shape

A
  • a molecule of O2 binds to one of the four haem units
  • this causes a slight change in the tertiary structures of the other haem units
  • this change increases the affinity for O2 allowing the second and third O2 molecules to bind easier
  • the 4th O2 is harder to bind than the second and third
14
Q

what happens when the HbO2 dissociation curve shifts to the right

A
  • at the same partial pressure of O2, the affinity of Hb for O2 decreases
  • more O2 is dissociated from the Hb to the tissues
15
Q

what happens when the HbO2 dissociation curve shifts to the left

A
  • at the same partial pressure of O2, the affinity of Hb for O2 increases
  • more O2 is loaded at lower partial pressures
16
Q

Why does foetal haemoglobin have a curve shifted to the left

A
  • low ppO2 in the placenta
  • shift to left = higher affinity for O2
  • more loaded at lower ppO2
17
Q

why do animals at high altitudes have a curve shifted to left

A
  • low ppO2 in high altitudes
  • shift to left = higher affinity for O2
  • more loaded at lower ppO2

A Level Biology Y1 (8 decks)

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