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AS Biology > 2.9 - Adaptations for transport > Flashcards

2.9 - Adaptations for transport Flashcards

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1
Q

What must transport systems in animals have?

A
  • suitable medium to carry materials
  • a pump (like the heart) to move blood
  • valves to maintain flow in one direction
  • repsiratory pigment for oxygen
  • a system of vessels for transport
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2
Q

What is an open circulatory system?

A
  • the blood does not move around the body in blood vessels but it bathes tissues directly while held in a cavity called the haemcoel
  • example insects
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3
Q

What are closed circulatory systems and the name of the 2 types?

A
  • the blood moves in blood vessels
  • single circulation
  • double circulation
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4
Q

What is single circulation?

A

The blood moves through the heart once in its passage around the body (example earthworm and fish)

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5
Q

What is double circulation?

A

The blood passes through the heart twice in its circuit around the body (example mammals)

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6
Q

What are the 2 types of double circulation?

A
  • pulmonary circulation
  • systemic circulation
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7
Q

What is pulmonary circulation?

A

serves the lungs, the right side of the heart pumps deoxygenated blood into the lungs. Oxygenated blood returns from the lungs to the left side of the heart.

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8
Q

What is systemic circulation?

A

Serves the body tissues, the left side of the heart pumps the oxygenated blood to the tissues. Deoxygenated blood from the body returns to the right side of the heart

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9
Q

Why is double circulation more efficient than single circulation?

A

Oxygenated blood can be pumped around the body at higher pressures

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10
Q

What are the 3 types of blood vessels?

A

Arteries, veins, capillaries

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11
Q

What 3 features do arteries and veins contain?

A
  • endothelium (one cell thick, smooth, reduced friction to bloodflow)
  • tunica media (elastic, smooth, allows changes in flow and pressure)
  • tunica externa (collagen fibres resist over stretching)
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12
Q

What are arteries? (3 points)

A
  • carries blood away from the heart
  • thick, muscular walls withstand high pressure
  • branch into arterioles and then capillaries
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13
Q

What are capillaries (2 points)

A
  • vast network that connects all organs and tissues
  • capillaries into venules, into veins (into the heart)
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14
Q

What are veins? (4 points)

A
  • larger diameter lumen and thinner walls (less muscle)
  • blood pressure and flow rate lower
  • veins above heart return by gravity
  • semi-lunar valves ensure one direction and no back flow
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15
Q

What are the 2 main parts of the heart?

A

atria - above 2 thicker walled pumping chambers
ventricles - allowing complete separation of blood type

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16
Q

What is the heart mainly made of?

A

Cardiac tissue (specialised)

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17
Q

How does the heart contract?

A

Myogenic contractions

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18
Q

What are myogenic contractions?

A

The heartbeat is inititiated within muscle cells themselves and not dependant on nervous or hormonal stimulation (but can be affected by them)

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19
Q

What is the cardiac cycle?

A
  • describes one heartbeat (0.8 seconds)
  • systole contractions, diastole relaxations
  • atrial systole, ventricular systole, diastole
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20
Q

What happens in the atrial systole phase of the cardiac cycle?

A

Atrium walls contract and blood pressure increases, blood pushes through tricuspid and bicuspid valves down to the ventricles, which are relaxed

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21
Q

What happens in the ventricular systole phase of the cardiac cycle?

A
  • ventricle walls contract, increasing pressure, forces blood up through semi-lunar valves, into pulmonary artery and aorta
    -tri-bicuspid valves close by rise in ventricular pressure
22
Q

Where does the pulmonary artery go?

A

Takes deoxygenated blood to the lungs

23
Q

Where does the aorta lead?

A

Takes oxygenated blood around the body

24
Q

What happens in the diastole phase in the cardiac cycle?

A
  • ventricles relax, volume of the ventricles increase and pressure decreases, semi-lunar valves shut to prevent backflow
  • atria relax, so blood from vena cavae and pulmonary veins enters atria and repeats cycle
25
Q

Why is the left ventricle thicker?

A

Left ventricle has thicker muscle wall than the right as it has to pump blood all around the body, where as right only has to pump blood to the lungs

26
Q

What are valves and how do they work?

A
  • prevent backflow of blood
  • the atrio-ventricular valves (bi/tri) semi lunar (aorta + veins) all operate by closing under high pressure, preventing blood flowing backwards
27
Q

What is the sino-atrial node? (SAN)

A

An area of the heart muscle in the right atrium that intitiates a wave of electrical excitation across the atria, to generate contraction of the heart muscle. It is also called the pacemaker.

28
Q

What is the atrio-ventricular node? (AVN)

A

The only conducting are of tissue in the wall of the heart between the atria and the ventricles, through which electrical excitation passes from the atria to conducting tissue in the walls of the ventricles.

29
Q

What are the 5 stages of controlling the heartbeat( (SAN/AVN)

A

1) electrical simulation at SAN spreads over both atria, so they contract together
2) AVN recieves impulse, creates a delay to ensure emptying of ventricles
3) AVN passes excitation down nerves to the bundle of His, it is then transmitted to Purkinje fibres in the ventricle walls
4) The impulses cause cardiac muscle in each ventricle to contract simultaneously, from apex upwards
5) pushes blood up to the aorta and pulmonary artery, and empties ventricles completely

30
Q

What is an electrocardiogram?

A

An ECG is a trace of voltage changes produced by the heart, detected by electrodes in the skin

31
Q

Describe a typical ECG.

A

p wave = sino atrial node, contraction of atria
P-QRS = PR interval/ excitation from SAN to AVN
QRS = depolarisation, contraction of ventricles
T = repolarisation ventricle muscles (QRS-T = ST segment)
TP = baseline of trace, isoelectric wave

32
Q

Signs of atrial fibrillation on an ECG?

A

Rapid heartbeat/ no p wave

33
Q

Signs of a heart attack on an ECG?

A

Wide QRS complex

34
Q

Signs of enlarged ventricle walls on an ECG?

A

QRS complex showing a greater voltage change

35
Q

Signs of atherosclerosis on an ECG?

A

Changes in ST segment and T wave (signs of blockage)

36
Q

What is blood?

A

Tissue made up of cells (45%) in solution of plasma (55%)

37
Q

What are red blood cells? (erythrocytes)

A
  • contain haemoglobin (oxygen transport)
  • biconcave disks (more oxygen, reduced diffusion distance)
  • no nucleus (more haemoglobin, more oxygen)
38
Q

What is blood plasma and what does it contain?

A
  • pale yellow liquid (95% water)
  • solutes (glucose, amino acids, vit b+c, minerals)
  • waste products (urea, HCO3-)
  • hormones and proteins (albumin, blood clotters, antibodies)
  • distributer of heat
39
Q

What is the equation for the transport of oxygen?

A

oxygen + haemglobin = oxyhaemoblobin
4O2 + Hb = Hb.4O2

40
Q

How does haemoglobin change for oxygen?

A

Changes its affinity to oxygen by changing its shape

41
Q

What is meant by the term ‘affinity’?

A

The degree to which 2 molcules are attracted to eachother.

42
Q

What does haemoglobin contain to bind oxygen?

A

Haemoglobin contains 4 haem groups containing iron (Fe2+) and one oxygen can bind to each

43
Q

How does each oxygen bind to the haemoglobin?

A
  • 1st oxygen changes h.shape so easier 2nd O2 attachment
    -2nd oxygen changes h.shape so easier 3rd attachment (co-operative binding)
    -3rd oxygen no change in h.shape so large increase in oxygen partial pressure to bind 4th oxygen
44
Q

What effect does CO2 have on oxygen distribution?

A

The Bohr effect
- the movement of the oxygen dissociation curve to the right at a higher partial pressure of CO2, because at a given oxygen partial pressure, the haemoglobin has a lower affintity for oxygen

45
Q

What are the 4 main features of an oxygen dissociation curve?

A

1) when haemoglobin is exposed to an increase in oxygen partial pressure, it absorbs oxygen rapidly at low partial pressures but more slowly when pressure rises
2) when the oxygen partial pressure is high, as in the lung capillaries, oxygen combines with the haemoglobin to form oxyhaemoglobin
3) when the partial pressure is low, as in respiring tissues, the oxygen dissociates from oxyhaemoglobin
4) when partial pressure of carbon dioxide is high, haemoglobin has a lower affintity for oxygen so less efficient at loading oxygen and more efficient at unloading it

46
Q

What are the 3 main ways CO2 is transported?

A
  • solution of plasma (5%)
  • hydrogen carbonate ions, HCO3 (85%)
  • haemoglobin (carbamine haemoglobin) (10%)
47
Q

What is the 7 stage process of Co2 and red blood cells?

A
  • CO2 diffuses into the red blood cell
  • carbonic anhydrase catalyses the combination of CO2 + h20, making carbonic acid
  • carbonic acid = H+ HCO3-
  • HCO3- diffuse into the plasma (waste product)
  • chloride shift (Cl-) into red blood cell (electrochemical neutrality)
  • H+ causes oxygen to dissociate, then combines with haemoglobin to make haemoglobin acid HHB (removing H+ ions sp the pH of red blood cells does not fall)
  • oxygen diffuses into the tissues
48
Q

How are capillaries adapted to allow exchange in materials?

A
  • thin, permeable walls
  • large surface area for exchange of materials
  • blood flows slowly so more time for exchange
49
Q

What happens when fluids are forced through the capillary walls?

A

Fluid from plasma is forced through the capillary walls, as tissue fluid bathes the cells, supplying them with solutes such as glucose, amino acids, fatty acids, salts, hormones and oxygen

50
Q

What does the diffusion of solutes relate to?

A

The diffusion of solutes in and out of the capillaries relates to the bloods hydrostatic pressure and solute potential.

51
Q

What happens at the arterial end of a capillary bed?

A
  • high hydrostatic pressure pushes liquids outwards from the capillary to the spaces in between cells
  • plasma has low solute potential, pulling water back into the capillary by osmosis
  • hydrostatics pressure is greater than the plasmas solute potential, so water and solutes are forced out through the capillary walls into the spaces between the cells
  • solutes such as glucose, oxygen and minerals are used during cell metabolism so their concontration in and around the cells are low, but in the blood higher. this favours the diffusion from the capillaries to the tissue fluid
52
Q

What happens at the venous end of a capillary bed?

A
  • bloods hydrostatic pressure is lower than at the arterial end because much fluid has been lost
  • plasma proteins are more concentrated in the blood as water has been lost, the solute potential of the plasma is more negative. The osmotic force pulling water inwards is greater than the hydrostatic pressure pushing water outwards so water passes back into the capillaries by osmosis
  • tissue fluid surrounding cells picks up CO2 and other wastes, which diffuse down the conc gradient from the cells where they are made, and into the capillaires where they are less concentrated
  • not all fluid passes back into the capillaries, around 10% drains into the lymph capillaries of the lymphatic system. It returns to the venous system through the thoractic duct, which empties into the left subclavian vein above the heart

AS Biology (11 decks)

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