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Human Anatomy & Kinanthropometry > C3 - Adaptations to Animal Transport > Flashcards

C3 - Adaptations to Animal Transport Flashcards

1
Q

Why can’t blood in the lungs travel straight to the body?

A

Because the pressure is reduced in lungs so too low to make circulation efficient to the rest of the body.

INSTEAD, blood returns to heart where it’s pressure ⬆️.

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2
Q

What is the inner most layer of a blood vessel called?

A

Endothelium:

1 cell thick

Surrounded by tunica intima

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3
Q

Define the tunica intima

A

Smooth lining reducing friction w/ minimum resistance to blood flow.

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4
Q

What is the middle layer of a blood vessel called?

A

Tunica media:

Contains elastic fibres + smooth muscle

Thicker in arteries than veins

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5
Q

What do the elastic fibres in the tunica media of arteries allow?

A

Allow stretching to accommodate changes in blood flow + bp.

They then go into recoil, pushing blood on through the artery. = Pulse + maintains blood pressure.

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6
Q

What does the contraction of smooth muscle in the tunica media allow?

A

Regulates blood flow + maintains bp as blood is transported further away from heart.

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7
Q

What is the outer layer of a blood vessel called?

A

Tunica externa:

Contains collagen fibres that resist over-stretching

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8
Q

Define the capillaries

A

Form a vast network that penetrates all tissues + organs of body.

Blood from here collects into venules which take blood to veins back to heart.

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9
Q

Describe the structure of capillaries

A

Thin walls - 1 layer of endothelium on basement membrane.

Gaps between cells make them permeable to H20 + solutes, i.e glucose

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10
Q

How is there plenty of time for the exchange of materials with the surrounding tissue fluid from the capillaries

A

Slower rate of blood flow

Many capillaries in capillary bed

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11
Q

What type of contraction does the heart have?

A

Myogenic

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12
Q

What does myogenic mean

A

It can contract and relax rhythmically of its own accord.

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13
Q

What is the heart rate modified by?

A

Nervous and hormonal stimulation

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14
Q

What is meant by the cardiac cycle

A

Sequence of events that makes a heartbeat.

Normally lasts about 0.8 secs.

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15
Q

What are the 3 stages of the cardiac cycle

A

Atrial systole

Ventricular systole

Diastole

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16
Q

What happens during atrial systole

A

Atrium walls contract

Bp in atria ⬆️

== This pushes blood through tricuspid + bicuspid valves down to ventricles down pressure gradient.

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17
Q

What happens during ventricular systole

A

Ventricle walls contract

⬆️ bp in ventricles

== This forces blood up through semi-lunar valves out of heart into pulmonary artery + aorta

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18
Q

Why can’t the blood flow back from the ventricles into the atria during ventricular systole?

A

Because the tricuspid + bicuspid valves close due to the rise in ventricular pressure

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19
Q

What happens during diastole

A

Atria + Ventricles relax.

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20
Q

Explain the ventricles relaxing during diastole

A

Volume of ventricles ⬆️ = pressure ⬇️

== This risks blood in pulmonary artery + aorta to flow back down into ventricles but don’t due to semi-lunar valves closing

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21
Q

Explain the atria relaxing during diastole

A

Causes blood from the vena cava + pulmonary veins to enter the atria for cycle to start again

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22
Q

Describe the flow of blood through the left side of the heart

A

Left atrium relaxes

Oxygenated blood from pulmonary vein enters

⬆️ pressure forces bicuspid valve to open

Left ventricle is relaxed so blood is drawn in from left atrium

Left atrium contracts to push remaining blood into left ventricle

Bicuspid valve closes

Left ventricle contracts

Strong muscular wall exerts high pressure to push blood up out of heart, through semi lunar valves into aorta + closes bicuspid valve to prevent back flow into left atrium.

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23
Q

What are the atrioventricular valves

A

Bicuspid + tricuspid

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24
Q

Where is the SAN?

A

In the wall of the right atrium as a cluster of specialised cardiac cells that acts as a pace maker

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25
Q

How is a heartbeat produced?

A

SAN initiates wave of excitation which spreads over walls of atria = ATRIAL SYSTOLE

Wave reaches layer of non-conducive connective tissue called AV septum = preventing wave spreading to ventricles.

AVN induces a delay in the wave to allow atria to complete contraction before ventricular systole.

Wave passes down the nerves of the bundle of His to the apex of the heart.

Then transmitted to purkinje fibres in ventricle walls.

Impulses cause cardiac muscle in each ventricle to contract simultaneously from apex upwards.

This pushes blood up to aorta + pulmonary artery.

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26
Q

What is an electrocardiogram, (ECG)?

A

A trace of the voltage changes produced by the heart detected by electrodes on the skin.

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27
Q

What does the P wave on an ECG signify?

A

Depolarisation of the atria so ATRIAL SYSTOLE.

P waves are small due to atria having less muscle than the ventricles.

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28
Q

What is the time between the start of the P wave and the start of the QRS complex?

A

PR interval

== time taken for the excitation to spread from the atria to the ventricles through the AVN.

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29
Q

What does the QRS wave on an ECG signify?

A

Shows the depolarisation + contraction of the ventricles.

Ventricles have more muscle than the atria so amplitude is bigger than that of a P wave.

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30
Q

What does the T wave on an ECG signify?

A

Repolarisation of the ventricle muscles during diastole

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31
Q

How long does the ST segment last for?

A

from the end of the S wave to the beginning of the T wave

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32
Q

What’s the isoelectric line on an ECG?

A

The line between the T wave and P wave on the next cycle

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33
Q

How can you tell using an ECG if a person has atria fibrillation

A

Rapid HR

May lack P wave

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34
Q

How can you tell using an ECG if a person has had a heart attack

A

may have a wide QRS complex

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35
Q

How can you tell using an ECG if a person has enlarged ventricle walls?

A

May have a QRS complex showing greater voltage change

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36
Q

What might changes in the height of the ST segment and T wave indicate?

A

Insufficient blood being delivered to heart muscle

i.e due to blocked coronary arteries + atherosclerosis.

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37
Q

How do you calculate HR using an ECG?

A

60 / seconds

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38
Q

How does pressure change in the aorta

A

Ventricular contraction

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39
Q

If the heart is myogenic what are the other muscles?

A

Neurogenic

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40
Q

When do valves open?

A

AV = when pressure above is greater than below. i.e atrium greater than ventricle.

SL = When pressure in ventricles are greater than the artery.

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41
Q

When looking at numbers for blood pressure, which number is the systole and diastole?

A

Systole = UPPER / BIGGER

Diastole = Lower/ Smaller

42
Q

What are the advantages of a closed circulatory system?

A

Blood flow is more rapid + efficient

Vascular shunting by vasoconstriction/dilation

In a double = pressure is high + maintained

43
Q

Why would an oximeter be useful for monitoring the condition of a patient suffering from a chronic lung disease?

A

Allows you to monitor level of O2 in blood

44
Q

How can SAN be affected?

A

Accelerator nerve

Vagus nerve

Adrenaline - speeds up HR

45
Q

What does the accelerator nerve do

A

Releases noradrenaline which speeds up HR

46
Q

What does the vagus nerve do

A

Releases acetylcholine which slows down HR

47
Q

How can the electrical signals using a cardiogram be shown?

A

On a cathode ray oscilloscopi or chart recorder.

48
Q

Link all cardiac control, action of heart muscle and ECG activity together

A

SAN - Atrial Systole - P wave

AVN - No contraction - Flat

Purkinje fibres - Ventrilucar Systole - QRS complex

None - Diastole - T wave

49
Q

What condition are the AV valves in during the different phases of the cardiac cycle?

A

Atrial systole = OPEN

Ventricular systole = CLOSED

Diastole = OPEN

50
Q

What condition are the semi-lunar valves in during the different phases of the cardiac cycle?

A

Atrial systole = CLOSED

Ventricular systole = OPEN

Diastole = CLOSED

51
Q

Explain how the structure of the aorta relates to its function

A

Thick muscular wall to w/stand high pressure

Smaller lumen to maintain the High pressure especially as its transporting oxygenated blood to the body from left ventricle

Elastic fibres that stretch to accommodate high pressure and prevent bursting. Then go into recoil to push blood along.

Smooth endothelium to reduce friction

52
Q

Suggest why there no exchange between the blood in the arteries, arterioles, venues and veins with the tissues

A

Because they have 3 layers of tissues so diffusion and exchange would be too slow so inefficient.

53
Q

Give 2 functions of the circular muscles in the walls of the arteries

A

To allow vasoconstriction/dilation to direct blood flow to specific parts of the body.

To ⬆️ bp by constricting or help to maintain pressure.

54
Q

What is the function of the coronary arteries?

A

To transport glucose and O2 to the cardiac muscles.

55
Q

List 4 conditions that can be detected from changes in the ECG

A

Tachycardia

Fibrillation

Bradycardia

Ectopic heartbeat

56
Q

Define tachycardia

A

Fast resting HR of over 100 beats per min

57
Q

Define fibrillation

A

An uncoordinated and irregular HB

58
Q

Define bradycardia

A

Excessively low HR

59
Q

Define ectopic HB

A

Extra or skipped beat

60
Q

When might the nervous system be involved in the heart beat/cycle?

A

When altering the frequency and force of these contractions to meet body needs.

61
Q

What are RBC’s also known as and why are they red?

A

Erythrocytes

Red because they contain haemoglobin.

62
Q

Describe the structure of a RBC

A

NO nucleus = more room for haemoglobin + maximises O2 that can be carried

Biconcave discs = Larger SA so more O2 diffuses across membrane.

63
Q

How are the capillaries well adapted to allow the exchange of materials?

A

Thin + permeable walls = short diffusion pathway

Thousands of them = large SA for exchange of materials

Slow blood flow through capillaries allowing time for the exchange of materials

64
Q

Describe the movement of tissue fluid in capillary bed at the atrial end

A

High HP due to pumping of heart + resistance to blood flow in capillaries.

== forces fluid out of blood into tissues.

This outward flow is opposed by the ⬇️ water pot of blood in capillaries due to plasma proteins.

HP is greater than the osmotic force so there’s a net flow of fluid out taking glucose, O2 + ions into tissue.

65
Q

Describe the movement of tissue fluid in capillary bed at the venous end

A

⬇️ Bp = HP is less than the reduced water pot of blood due to plasma proteins.

== Net flow of fluid into capillaries, removing CO2 + urea

66
Q

What 2 reasons are there for the drop in HP at the venous end?

A

Large SA of capillaries creating friction

Loss of tissue fluid

67
Q

Explain plasma

A

Pale yellow liquid, 90% water containing:

  • Solutes i.e glucose, aa, vitamin B + C, mineral ions
  • Waste products i.e urea
  • Hormones
  • Plasma proteins

Also distributes heat.

68
Q

Define affinity

A

Degree to which 2 molecules are attracted to each other

69
Q

Define cooperative binding

A

⬆️ ease w/ which haemoglobin bind its 2nd + 3rd molecules as the conformation of the haemoglobin molecule changes.

70
Q

Chemical formula for oxygen + haemoglobin

A

4O2 + Hb —– Hb4O2

71
Q

What must happen to transport O2 efficiently?

A

Haemoglobin must associate readily w/ O2 at the alveoli + readily dissociate at respiring tissues.

72
Q

How does haemoglobin change its affinity for O2?

A

By changing its shape

1st O2 that attaches to haemoglobin changes its shape making it easier for the 2nd molecule to attach.

2nd molecule does the same for 3rd.
== COOPERATIVE BINDING

3rd O2 molecule doesn’t induce a shape change so the binding of the 4th O2 molecule requires a large ⬆️ in O2 partial pressure.

73
Q

How many O2 molecules can bind to each iron in the iron containing haem groups

A

1

== 4 in total

74
Q

Define partial pressure

A

The pressure a gas would exert is it were the only one present.

Normal atmospheric pressure - around 100kPa.

75
Q

What shape is shown in an O2 dissociation curve and why?

A

Sigmoid (s-shape) because of cooperative binding.

76
Q

What would happen at higher pp of O2 if the relationship between pp of O2 + % saturation of haemoglobin w/ O2 were linear?

A

Hb’s O2 affinity would be too low + so O2 would be readily released + not reach respiring tissues.

77
Q

What would happen at lower pp of O2 if the relationship between pp of O2 + % saturation of haemoglobin w/ O2 were linear?

A

Hb’s O2 affinity would be too high + O2 would not be released in respiring tissues, even at low O2pp.

78
Q

What must the haemoglobin in the blood of a foetus must be able to do?

A

To absorb the O2 from the maternal Hb at the placenta at any pp of O2.

79
Q

How does fetal Hb differ from adult Hb

A

Fetal has 2 alpha + 2 gamma polypeptide chains

== gives it a higher affinity for O2 than mother’s Hb at the SAME pp of O2.

80
Q

What happens to the dissociation curve of a fetal haemoglobin compared to an adult one?

A

Whole curve moves to left

= % sat of the foetus’ blood higher than mothers.

81
Q

When does fetal Hb convert to adult Hb?

A

6 months due to needing to release O2 to moving muscle and otherwise they wouldn’t have a Hb w/ lower affinity to O2 than their future baby if pregnant.

82
Q

What happens to oxyHb when CO2 concentrations ⬆️?

A

OxyHb releases O2 more readily.

So dissociation curve moves to the right. Shift is called the Bohr Effect

83
Q

What does the Bohr effect account for?

A

The unloading of O2 from oxyHb in respiring tissues where pp of CO2 ⬆️ and O2 is needed.

84
Q

What are the 3 ways in which CO2 is transported?

A

5% in solution in the plasma

85% as H carbonate ion - HCO3-

10% bound to Hb as carbaminoHb

85
Q

Describe the reactions in RBC in which CO2 is converted into H carbonate to then diffuse into the plasma

A

CO2 in blood diff into RBC down conc. grad.

Carbonic anhydrase catalyses Co2 + H2O into Carbonic acid (H2CO3) a.k.a bicarbonate

H2CO3 dissociates into H+ + H carbonate ions (HCO3-)

HCO3- ions diff out of RBC into plasma.

To balance outflow of -ive ions + maintain electrochemical neutrality, chloride ions diff INTO RBC from plasma. == CHLORIDE SHIFT

H+ ions cause OxyHb to dissociate – O2 + Hb. (Displaces the O2)

H+ + Hb – Hb acid (HHb) which removes H ions + so pH of RBC doesn’t fall.

O2 diff OUT of RBC into tissues.

86
Q

What do the reactions in RBC in which CO2 is converted into H carbonate to then diffuse into the plasma explain?

A

Why most CO2 is carried in the plasma as HCO3- ions

Bohr effect - higher pp of CO2, the lower the affinity of Hb for O2.

How CO2 results in the delivery of O2 to respiring tissues.

87
Q

Why could the narrowing of the coronary arteries lead to the heart not contracting?

A

Because it would reduce the blood supply to the heart muscle containing O2 + glucoses so won’t be able to respire aerobically to produce the ATP required for contraction.

88
Q

Why do we need respiratory pigments?

A

If O2 was carried by H20:

  • At body temp = only 25cm^3 of O2 can be carried in 1dm^3 of blood.

O2 carried by Hb:

195cm^3 of O2 can be carried in 1dm^3:

1dm^3 = 150g Hb

1g of Hb can combine w/ 1.3cm^3 of O2

89
Q

How many haem groups does myoglobin have?

A

1

90
Q

What % of fluid forced out at arterial end returns to the venous end of the capillary bed in the movement of tissue fluid?

What happens to the remaining tissue fluid?

A

90%

Remaining - removed by drainage into lymphatic system where it is called lymph

91
Q

Describe lymph

A

Similar composition to tissue fluid but contains MORE lipids + CO2 but LESS O2 + nutrients.

92
Q

What do lymph vessels do?

A

Form a drainage network + return lymph to the blood stream via the subclavian vein in the neck.

93
Q

What happens if lymph vessels become blocked?

A

Swelling can occur in affected limbs due to accumulation of tissue fluid.

94
Q

What does low blood proteins mean in association to tissue fluid movement?

A

Low blood proteins can affect capillary filtration which may result in fluid retention in tissues - ODEMA i.e Kwashiorkor

95
Q

Explain what happens in Kwashiorkor

A

Stomach is full of fluid due to lack of protein.

== ⬇️ plasma proteins = ⬆️ water pot of capillary so fluid doesn’t move back in at the venous end from tissues by osmosis.

OR

Due to high bp:

⬆️ hydrostatic pressure at the ARTERIOLE end will force more fluid out.

⬆️ HP at VENOUS end will make return of fluid into capillary more difficult.

96
Q

Why might a seal require a higher O2 carrying capacity than a human?

A

Much higher myoglobin content in seal muscle than human so more O2 will be available to be dissociated for when seal is working aerobically i.e underwater

97
Q

What is meant by the term convergent evolution?

A

Molecules that have different structures but are adapted to carry out the same function

98
Q

How does an increase in minute volume result in a decrease in pCO2 of blood in alveolar capillaries

A

⬆️ diff of CO2 OUT of blood into alveoli so more CO2 is removed from blood.

99
Q

Why might people w/ reduced blood pCO2 commonly feel tired + lack energy?

A

Because there would be less CO2 to diff INTO RBC to dissociate into H+ ions to attach to the Hb to displace the O2 meaning less O2 available to cell for aerobic reps to produce energy.

100
Q

How does the production of hydrogen carbonate ions account for the Bohr effect

A

Production of h+ ions from the dissociation of carbon acid displaces O2 from Hb by combining it w/ it == ⬇️ pH.

101
Q

Explain the mechanisms + significance of the Bohr effect during exercise

A

Temp of muscles ⬆️ due to contraction as aerobic resp is not 100% efficient.

pH ⬇️ due to lactic acid if anaerobic + CO2 is aerobic = this ⬆️ in CO2 means more H+ will be produced.

H+ displaces O2 from oxyHb making it ⬇️ saturated.

Significance = Releases more O2 to muscles when respiring aerobically.

Human Anatomy & Kinanthropometry (27 decks)

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