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Biology🧬 > Transport In Animals❤️ > Flashcards

Transport In Animals❤️ Flashcards

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1
Q

Why do large organisms require vascular systems?

A

Because diffusion is inefficient over large distances

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2
Q

What is mass transport?

A

The bulk movement of substances through a transport system using force

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3
Q

Open circulation

A
  • Blood doesn’t flow through vessels
  • Flows freely over tissues
  • Flow is slow and at low pressure
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4
Q

Closed circulation

A
  • Blood flows through vessels
  • Flows at high pressure
  • Transported by a respiratory pigment
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5
Q

Single circulation, e.g. in a fish

A
  • Blood passes through heart once in every circuit
  • Blood leaves heart under high pressure
  • The pressure falls
  • Blood flows slowly around the rest of the body before returning to the heart
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6
Q

Double circulation

A
  • Blood passes through the heart twice in every circuit
  • Pulmonary circulation - heart and lungs
  • Systemic circulation - heart and rest of the body
  • Flow is is fast and under high pressure
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7
Q

The flow of blood in a double circulatory system

A
  • The right pumps deoxygenated blood to the lungs
  • Oxygenated blood returns to left
  • The left pumps oxygenated blood to the tissues
  • Deoxygenated blood returns to the right
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8
Q

Pulmonary artery function

A

Carries deoxygenated blood to lungs from right ventricle

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9
Q

Pulmonary vein function

A

Carries oxygenated blood from lungs to left atrium

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10
Q

Aorta function

A

Carries oxygenated blood from left ventricle to rest of the body

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11
Q

Vena cava function

A

Carries deoxygenated blood from body to right atrium

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12
Q

Atria function

A

Thin walled chambers which receive blood

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13
Q

Ventricles function

A

Generate a high pressure of blood to force it over a great distance

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14
Q

Why are the walls of the left ventricle thicker?

A

More muscular to generate a higher pressure so the blood can travel a greater distance to the extremities of the body

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15
Q

Atrioventricular valves function

A

Prevent backflow of blood from the ventricles to the atria during ventricular systole

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16
Q

Valve tendons/heart strings function

A

Keep valves under tension and prevent them from inverting during ventricular systole

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17
Q

Semi lunar valves function

A

Prevent backflow of blood from the arteries to the ventricles

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18
Q

Open circulation in insects

A
  • Blood is pumped by a dorsal tube shaped heart

* Flows freely over tissues and thought spaces known as haemocoel

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19
Q

Closed circulation in earthworms

A
  • Blood vessels under pressure
  • Respiratory gases transported in blood
  • Organs not in direct contact with blood
  • Blood contains haemoglobin
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20
Q

What is myogenic muscle?

A

Can initiate its own contractions

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21
Q

Atrial systole

A
  • The atria contract - volume decreases, pressure increases above ventricular pressure
  • The AV open
  • Blood flows into ventricles down a pressure gradient
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22
Q

Ventricular systole

A
  • The ventricles contract - volume decreases, pressure increases above atrial pressure
  • AV shut - produces lub sound
  • Ventricular pressure exceeds aortic pressure
  • SLV open
  • Blood enters the arteries
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23
Q

Diastole

A
  • Atria and ventricles relax - pressure decreases
  • Ventricular pressure falls below that of the arteries
  • SLV close - produces dub sound
  • Low pressure blood in the veins returns to the atria as the atria relax
  • Ventricular pressure falls below atrial pressure
  • AV open
  • Blood enters the ventricles
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24
Q

What is the cardiac cycle?

A

The sequence of events in one heartbeat

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25
Q

What is the SAN?

A
  • Sino-atrial mode
  • Acts as a pacemaker - sets base rate of contraction
  • Located in the wall of the right atrium
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26
Q

The cardiac impulse

A
  • An electrical impulse originates in the SAN and spreads across the atria, causing atrial systole
  • The impulse is picked up by the AVN in the right atrium
  • The impulse is conducted through the bundle of His to the apex of the ventricles
  • The impulse travels up through the Purkinje fibres, through the walls of the ventricles causing ventricular systole
  • The muscle cells of the ventricles repolarise during diastole
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27
Q

What is the function of an ECG?

A
  • Calculate the heart rate by measuring the time interval between the same points of successive cycles on the trace
  • Can be used to help diagnose cardiovascular disease and heart defects
28
Q

What does the P wave show?

A

The depolarisation of the atria during atrial systole

29
Q

What does the PR interval show?

A

Time for the impulse to spread to the ventricles

30
Q

What does the QRS wave show?

A

The spread of depolarisation through the ventricles during ventricular systole

31
Q

What does the T wave show?

A

The repolarisation of the ventricles during ventricular diastole

32
Q

Control of the cardiac activity

A
  • Heart rate can be varied by nerves that originate from the cardiovascular centre
  • Impulses can be sent via different neurones which cause involuntary changes to heart rate
  • Adrenaline can increase heart rate by causing SAN to discharge at a higher frequency
33
Q

Arteries

A
  • Transport blood away from heart
  • Blood under high pressure
  • Rapid blood flow
  • Thick layer of smooth muscle
  • Many elastic fibres
  • Endothelium present
  • Collagen fibres in outer layer
  • Small lumen
34
Q

Vein

A
  • Carry blood back to the heart
  • Blood under low pressure
  • Slow blood flow
  • Large lumen
  • Thin layer of smooth muscle
  • Little elastic tissue
  • Valves
  • Collagen fibres present in outer layer
  • Endothelium present
35
Q

Capillary

A
  • From arteriole to venule
  • Blood flows along pressure gradient
  • Pressure falls as blood passes through
  • Low pressure - reduced pressure gives more time for exchange
  • Slow blood flow
  • Small lumen
  • No muscle or elastic tissue
  • No outer layer
  • Endothelium present
36
Q

Arterioles

A

Connects arteries to capillaries

37
Q

Venules

A

Connect capillaries to veins

38
Q

Venous return

A

Blood flow back to the heart is difficult as the blood pressure is low in the veins and may be flowing against gravity

39
Q

What is venous return aided by?

A
  • Valves - prevent backflow
  • Muscles - squeeze against veins
  • Suction effect from diastole
  • Negative pressure in chest due to ventilation
40
Q

What is elastic recoil?

A

The elastic fibres push blood along the artery which produces an even flow of blood

41
Q

What is the purpose of the elastic fibres in the aorta?

A
  • During ventricular systole they allow the aorta to stretch to accommodate the blood entering
  • During diastole they recoil to maintain blood pressure
42
Q

Why does blood pressure and rate of flow decrease as blood travels further from the heart?

A
  • The increase in total cross sectional area

* Frictional resistance of blood flowing along the blood vessels

43
Q

Adaptations of capillaries

A
  • Dense network - S.A
  • Walls are one cell thick and flattened, small diameter, red blood cells in contact with wall - short diffusion pathway
  • Narrow lumen - reduces flow rate, giving more time for diffusion
  • Permeable walls - O2 and CO2 cans easily diffuse in and out
  • Pores in walls - allows formation of tissue fluid
44
Q

Plasma

A
  • Made up of water and solutes

* Transport the soluble products of digestion, ions, hormones, antibodies, excretory products and heat

45
Q

Red blood cells

A

Responsible for transporting respiratory gases around the body

46
Q

White blood cells

A

Involved in protecting the body against infection

47
Q

Platelets

A

Involved in blood clotting

48
Q

The formation of tissue fluid

A
  • Ultrafiltration occurs at the arteriol end of the capillary as the hydrostatic pressure is high - fluid moves out
  • The fluid forced out is now tissue fluid and it bathes the cells in essential nutrients
  • The hydrostatic pressure falls as fluid is forced out
  • Osmosis draws water back in at the venule end as the water potential of the blood is lower than that of the tissue fluid
49
Q

The lymphatic system

A
  • More fluid leaves the capillaries than is reabsorbed
  • Excess fluid drains into lymph capillaries
  • The lymph capillaries join to form lymph vessels which return the lymph to the blood via the thoracic duct
  • Lymph vessels have valves
50
Q

The quaternary structure of haemoglobin

A
  • Made up of 4 polypeptide chains, each containing a haem group
  • The haem groups contain iron ions which form a loose association with O2 molecules
  • Each molecule of haemoglobin can transport 4 molecules of oxygen
51
Q

Role of haemoglobin

A
  • Loads oxygen in the lungs

* Unloads oxygen at the tissues where it is needed for respiration

52
Q

What does the oxygen-haemoglobin dissociation curve show?

A

The relationship between the partial pressure of oxygen and the percentage saturation of haemoglobin with oxygen

53
Q

Why is the shape of the dissociation curve important?

A
  • S shape - Hb is efficient at loading O2 and can become fully saturated at a lower pO2 than if it was linear
  • Hb has a high affinity for O2 at a high pO2 and so loads O2 to form OHb
  • Hb has a low affinity for O2 at a low pO2 and so unloads O2
  • The steep part means that for a small decrease in pO2, there’ll be a large decrease in % saturation of Hb so more O2 will be unloaded to the tissues for aerobic respiration
54
Q

Fetal haemoglobin

A
  • Higher affinity for oxygen - at any pO2, % saturation is higher
  • Maternal Hb will unload 70% O2 to placenta, fetal Hb will load O2 from placenta to become 80% saturated
  • Curve will appear to the left of adult Hb
55
Q

Dissociation of organisms in low O2 environments

A
  • E.g. llamas and lugworms
  • Pigments with higher affinity for O2 - to the left of adult Hb
  • Can load more O2 and Hb can be fully saturated at a lower pO2
56
Q

What is myoglobin?

A
  • The respiratory pigment found in muscle fibres

* Appears to the left of adult Hb

57
Q

The Bohr effect

A
  • During exercise the rate of respiration increases as the muscles need more ATP
  • This produces more CO2 which lowers the pH of the blood
  • This causes the dissociation here to shift to the right
  • Hb has a lower affinity for O2 - at any pO2, %saturation is lower
58
Q

What is the advantage of the Bohr effect?

A

Hb unloads more O2 to the respiring muscle tissues for an increased rate of respiration

59
Q

Three ways CO2 is transported in the blood

A
  • 5% dissolves directly in plasma
  • 10% combined with amino groups in Hb to form carbaminohaemoglobin
  • 85% as hydrogen carbonate
60
Q

What is chloride shift?

A
  • Chloride ions diffuse into the red blood cells from the plasma
  • Balance the electrical charge as the diffusion of hydrogen carbonate ions out of the cell left the membrane positively charged
  • Maintain electrochemical neutrality
61
Q

Reversible equation of haemoglobin and oxygen

A

Hb+4O2 -> oxyHb

62
Q

3 adaptations of red blood cells

A
  • Bioconcave - more S.A.
  • Haemoglobin - high affinity for O2
  • No nucleus - more space for Hb
63
Q

What is the affinity like in Hb in respiring tissues?

A

Low because it means that Hb dissociates O2 which unloads more O2 for the tissues

64
Q

What is a pH buffer?

A

Keeps the pH at an optimum level - Hb acts as a buffer in the RBC

65
Q

Transport of CO2

A
  • CO2 diffuses into the RBC
  • CO2 combines with H2O to form carbonic acid - reaction is catalysed by carbonic anhydrase
  • Carbonic acid dissociates into protons(H+) and hydrogen carbonate ions (HCO3-)
  • The haemoglobin acts as a buffer as the H+ will lower the pH of the cell
  • The oxyHb dissociates, unloading oxygen which diffuses into the tissues
  • HCO3- diffuses into the plasma
  • Chloride ions diffuse into the RBC from the plasma to obtain electro neutrality
66
Q

What is the function of the basement membrane surrounding the capillary?

A

To hold the endothelium and filter through molecules

Biology🧬 (24 decks)

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