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Human Health and Disease - J > Week 4 - Unit 4: Cardiovascular System Part 1 > Flashcards

Week 4 - Unit 4: Cardiovascular System Part 1 Flashcards

1
Q

Explain why a vein may be described as an organ.

A

Made of different tissues / more than one tissue

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2
Q 
Layer in wall	Thickness / µm
 	Artery	Vein
Endothelium	  20	  20
Smooth muscle	490	240
Elastic tissue	370	240
Connective tissue	120	120

Use information from the table to suggest the thickness of a capillary wall.
Give the reason for your answer.

A

20µm as it conists of endothelium only / does not contain muscle, connective tissue and elastic tissue

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3
Q 
Layer in wall	Thickness / µm
 	Artery	Vein
Endothelium	  20	  20
Smooth muscle	490	240
Elastic tissue	370	240
Connective tissue	120	120

The diameter of the artery was 4 mm. Calculate the diameter of the lumen of this artery.
Show your working.

A

Wall is 20 + 490 + 370 + 120 = 1000µm thick = 1mm
Diameter of lumen = Diameter of artery (4mm) – 2X wall thickness (2mm)

Answer 2mm / 2000 µm

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4
Q

Explain how the elastic tissue in the wall helps to even out the pressure of blood flowing through the artery.

A
  • Stretches as a result of high pressure / surge of blood

* Then recoils

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5
Q

Describe the advantage of having elastic tissue in the wall of an artery.

A

Allow recoil

For smooth blood flow / maintains blood pressure /avoids pressure surges

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6
Q

Calculate the cross-sectional area of the lumen of the artery shown in the diagram. Show your working.
The area of a circle is given by πr2, where r is the radius of a circle (π = 3.14).
• Radius measured from diagram (half of diameter) = 12 mm
image magnified X10

A

• Divide by 10 (because image is x10 magnification) = 1.2 mm
• 3.14 X 1.2 X 1.2 = 4.5 mm2
(ALLOW radius = 12.5 mm and subsequent correct calculations)

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7
Q

Name two substances which are at a higher concentration in the blood in an artery compared to a vein

A

ANY TWO: oxygen; glucose; amino acids; fatty acids; glycerol; minerals

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8
Q

Explain what causes the rate of blood flow to be slower in capillaries than in other vessels.

A
  • Small diameter / lumen / increase in total cross-sectional area
  • More surface in contact with blood
  • Greater friction /resistance
  • (Causes) loss of pressure
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9
Q

Which type of blood vessel has most elastic tissue in its wall?

A

• Artery

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10
Q

How does this elastic tissue help to smooth out the flow of blood in the blood vessel?

A
  • Stretches when ventricles contract / stretches to accommodate increase in blood volume / increase in blood pressure
  • Recoils when ventricles relax / when blood volume decreases / when blood pressure decreases
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11
Q

Describe why living organisms need a supply of Carbohydrates

A

For energy

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12
Q

Describe why living organisms need a supply of Proteins

A

For growth and repair

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13
Q

Describe why living organisms need a supply of fats

A

For energy and to make cell membranes

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14
Q

Describe why living organisms need a supply of vitamins

A

In small amounts for cells to work properly

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15
Q

Describe why living organisms need a supply of minerals

A

In small amounts to make body chemicals

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16
Q

Describe why living organisms need a supply of Oxygen

A

Needed for cellular aerobic respiration to release energy from organic fuels

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17
Q

Describe why living organisms need a supply of water

A

For chemical reactions to occur and for transport

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18
Q

How is carbon dioxide produced in the body

A

Produced as a by-product of cellular aerobic respiration, when oxygen is used to release energy from fuels

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19
Q

How is urea produced in the body?

A

A nitrogenous waste product produced by cellular metabolism and protein turnover

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20
Q

How is lactate produced in the body?

A

Produced as a result of anaerobic respiration where cells respire without oxygen

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21
Q

Why do humans need a transport system?

A

Organisms need special exchange surfaces in order to absorb substances that they require and to allow removal of waste substances.
Small (single-celled) organisms have a large SA:V ratio.
Nutrients and Waste can move in and out by simple diffusion alone.
No specialized exchange system(s) are needed.

Large (Multicellular) organisms have a small SA:V ratio.
Nutrients and Waste cannot move in and out by simple diffusion alone.
Specialized exchange systems are needed.

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22
Q

Summarise the structure & function of the blood, including its components and cells.

A

Blood is a tissue; made of cells, a fluid matrix known as plasma which contains proteins, as well as serum which contains nutrients.
Cells include:
Blood is always transported in blood vessels:
Along with the heart, and blood vessels; blood contributes to the circulatory system.

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23
Q

Identify what substances the blood transports around the body.

A

Nutrients and substrates (Glucose and Oxygen)
Waste and products (Urea and Carbon dioxide)
Chemical messengers (Hormones and cytokines)
Immunological components (White blood cells and antibodies)
Heat

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24
Q

What does blood regulate? (keep in homeostasis)

A 
pH
Body temperature
Water potential
Blood volume
Immune responses, inflammation and blood clotting (haemostasis)
Blood production (haematopoiesis)
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25
Q

Describe the structure of a red blood cell under a microscope

A

Red blood cells (Erythrocytes) are among the simplest of cells (approximately 7-8µm in diameter and 2-3µm thick). (Most other body cells are 10-30µm).
They lack a nucleus,
They have a biconcave shape
Their cytoplasm contains an iron-containing protein called haemoglobin.

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26
Q

What colour are the erythrocytes and why?

A

Red, because they contain hemoglobin which contains Iron – reflects red when oxidised.

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27
Q

Why do erythrocytes have no nucleus and a biconcave shape?

A

Increase volume in cytoplasm to contain more hemoglobin for more oxygen transport.

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28
Q

Most other animal body cells are 10-30µm in diameter. What limits the size of erythrocytes?

A

The lumen diameter of capillary vessels.

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29
Q

What might limit the lifespan of an Erythrocyte to approximately 120 days?

A

Wear and tear (oxidative stress accumulation) of hemoglobin and the cell membrane of the red blood cell.

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30
Q

How are erythrocytes formed?

A

Erythropoiesis – in bone marrow from special cytokine treatment of Hematopoietic stem cells.

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31
Q

What 5 things does the blood transport?

A

Nutrients, Waste, Chemical messengers, immunological components and heat.

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32
Q

Summarise the function of the human circulatory system

A

Functions:

  1. transport of respiratory gases (oxygen and carbon dioxide)
  2. transport of metabolites e.g. glucose, amino acids
  3. transport of metabolic wastes (e.g. urea)
  4. transport of hormones (from glands to target sites)
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33
Q

Identify and name the major blood vessels associated with the heart, lungs and kidney

A

Heart
Left and right coronary artery

lungs
pulmonary artery and vein

Kidney
renal artery and vein

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34
Q

Summarise the structure of the human circulatory system

A
  1. Heart acts as a pump
  2. Blood vessels (Arteries, arterioles, capillaries, venules, veins)
  3. The human circulatory system is a CLOSED SYSTEM because blood is confined to blood vessels

The advantage of this is: High blood pressure is maintained

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35
Q

The human circulatory system is a DOUBLE SYSTEM because:

A

Blood is pumped through the heart twice in one circulation

the advantages of this is High blood pressure maintained (therefore high flow rate)
and Oxygenated & deoxygenated blood kept separate (maintaining high diffusion gradients in lungs & tissues)

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36
Q

Name the one major artery that carries deoxygenated blood

A

Pulmonary artery

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37
Q

Name the one major vein that carries oxygenated blood.

A

Pulmonary vein

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38
Q

List the vessels of the heart in order from highest to lowest pressure.

A

Aorta
Pulmonary artery
Pulmonary vein
Vena cava

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39
Q

Blockage of coronary artery leads to heart attack. Why?

A

Prevents delivery of oxygen & glucose to cardiac (heart) muscle

So muscle can’t respire & dies (heart stops)

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40
Q

Why would High blood pressure in pulmonary artery cause a problem

A

Would force tissue fluid out of lung capillaries into alveoli
(so you’d drown!)

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41
Q

Explain why you might find blood clots in a heart during a dissection

A

A blood clot will form, if the heart valves are closed and blood is trapped inside the chambers.

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42
Q

Compare the structures of arteries, arterioles, veins and capillaries

A

capillaries - Wall made up of a single layer of endothelium

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43
Q

Compare the structures of arteries, arterioles, veins and capillaries

A
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44
Q

Describe the varying blood pressures in capillaries

A

Total cross-sectional area increases further, cause even more friction/resistance and loss of pressure.

Low blood pressure is important here because:
There is more time for diffusion of substances in/out of capillaries for exchange with surrounding tissues

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45
Q

Describe the varying blood pressures in capillaries

A

Total cross-sectional area increases further, cause even more friction/resistance and loss of pressure.

Low blood pressure is important here because:
There is more time for diffusion of substances in/out of capillaries for exchange with surrounding tissues

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46
Q

Describe the varying blood pressures in veins

A

Blood pressure is so low that valves are needed.

Valves: Prevent backflow of blood

47
Q

What are the 3 blood vessels called?

A

Arteries, Veins and Capillaries

48
Q

What are the 2 types of heart chamber called?

A

Atria and Ventricles

49
Q

How do heart valves work?

A

Pressure sensitive. Open when pressure behind the valve is greater than the pressure in front to ensure unidirectional blood flow.

50
Q

What are the two circuits called?

A

Pulmonary

Systemic

51
Q

What is the difference between the left side and right side of the heart, in terms of the blood transported?

A

Left side has oxygenated blood.Right side has deoxygenated blood.

52
Q

Which side of the heart is the thickest? Why?

A

Left side. Must pump blood at a higher pressure to enable perfusion of the whole body. Contrast to the right side which pumps blood a shorter distance to the lungs.

53
Q

Describe The Cardiac Cycle: 1 heart beat

A
  1. Atrial DiastoleThe heart beat begins when the heart muscles relax and blood flows into the atria.
  2. Atrial SystoleThe atria then contract and the valves open to force blood into the ventricles.
  3. Ventricle SystoleThe Ventricles contract forcing the blood to leave the heart. At the same time, the atria are relaxing and once again filling with blood.
54
Q

what stops back Flow of blood in the heart?

A

AV & SL valves in the heart are forced open or shut by pressure differences
However they can only open one way.This helps to prevent backflow of blood.The tendinous cords help heart values to stay in place.

55
Q

The cardiac cycle describes the events which occur during one heartbeat.
One whole cardiac cycle (1 heart beat) takes 0.8 seconds.
How many cycles take place in 1 minute? Show you working.

A

60 seconds / 0.8 for 1 cardiac cycle= 75 beats per minute.

This measurement is known as Heart rate.

56
Q

How is cardiac output calculated?

A

Cardiac output = stroke volume X heart rate

You need to be able to re-arrange this equation!

57
Q

Define cardiac output

A

Volume of blood pumped
by the heart per minute
(units: cm3min-1)

58
Q

Define stroke volume

A

Volume of blood pumped
during each heart beat
(units: cm3)

59
Q

Define heart rate

A

Number of heart beats per minute

units: min-1

60
Q

What is the stroke volume if your heart rate is 80 beats per minute and your cardiac output is 5440 cm3min-1?

A

68 cm3

61
Q

How does the heart beat automatically? what controls this?

A

The heart beats automatically:
Control centre: Medulla Oblongata in the brain
ANS: Sympathetic nervous system and accelerator nerve Parasympathetic nervous system and vagus nerve
Heart pacemakers:S.A.Node A.V.Node
Bundle of Hiss Purkije fibres

62
Q

The wave of electrical activity which coordinates the heart beat is delayed slightly at AV node. It then passes along part to the base of the ventricles.
Explain the importance of
(i) the slight delay at the AV node

A

To allow the atria to finish systole and finish emptying before the ventricles contract / systole.

63
Q

Explain the importance of:

(ii) the electrical activity being passed to the base of the ventricles.

A

The ventricles contract / systole from the apex / bottom upwards.
This generates an upward contraction force to pump the blood out of the heart and into the arteries effectively.

64
Q

Explain the importance of:

The electrical activity being passed to the base of the ventricles.

A

The ventricles contract / systole from the apex / bottom upwards.
This generates an upward contraction force to pump the blood out of the heart and into the arteries effectively.

65
Q

The maximum pressure in the ventricle is much higher than that in the atrium.
Explain what causes this.

A

The muscle wall is thicker in the ventricle, compared to the atria.
Contraction produces a greater force .
The blood is therefore pumped at higher pressure.

66
Q

The heart controls and coordinates the regular contraction of the atria and ventricles.
Describe how.

A 
Control = via pacemaker cells in the SA.Node and A.V.Node, and purkinjie fibres.
Coordination = nerve action potential conduction.

Starting in S.A.Node  atria contract  A.V.Node  slight delay  bundle of Hiss  purkinjie fibres  ventricles contract…

67
Q

What is the stroke volume if your heart rate is 80 beats per minute and your cardiac output is 5440 cm3min-1?

A 
CO = HR X SV
SV = CO / HR
SV = 5440cm3min-1 / 80min-1 = 
SV = 68cm3
68
Q

What determines the opening the closing of the Atrioventricular (AV) and Semilunar (SL) valves?
What does this help to ensure?

A

Pressure differences between the Atria, Ventricles and Arteries.
Prevents backflow of blood / ensures blood flow is unidirectional.

69
Q

What is a normal Heart rate (beats per minute) =

A

70bpm

70
Q

What is a normal Stroke volume (volume of blood per beat) =

A

70ml

71
Q

What is a normal Cardiac output (HR X SV) =

A

4.9litres per minute

72
Q

What is a normal Diastolic pressure (blood pressure when heart is relaxed) =

A

80mmHg

73
Q

What is a normal Systolic pressure (blood pressure when heart is contracted) =

A

120mmHg

74
Q

Describe the survival response

A

Stimulus = change in an organism’s internal or external environment.

Organisms respond to stimuli  increases changes of survival.

e. g. response to external temp. (too hot; too cold) to maintain optimum temp. for enzymes
e. g. response to internal environment to maintain optimum pH for enzymes.

75
Q

Animals respond by sending messages to different parts of the body (communication). Messages can be of two types:

A

(1) Hormonal communication
(2) Nervous communication

Both involve:
A receptor  to detect stimulus
A coordinator  to formulate a response
An effector  to produce a response

76
Q

What are Hormones?

A

Hormones = chemical messengers secreted by glands & transported in blood

Mostly proteins (e.g. insulin) or steroids (e.g. oestrogen)

Bind to specific receptors (proteins) on cell surface membranes of target cells.

77
Q

What is the receptor, hormone, effector and response to rise in blood sugar levels (stimulus)?

A

β-cells in

pancreas, insulin, liver or muscle cell, glycogenesis

78
Q

Nervous system consists of…

A

(1) CNS & PNS
(2) 3 types of neurone (transmit electrical impulses)
(3) Synapses (using chemical neurotransmitters )

79
Q

Describe the central nervous system.

A 
Central Nervous System (CNS)
Brain & spinal cord
Contains relay neurones
Processes sensory information
Decides what to do with it
Initiates a response
80
Q

Describe the Peripheral Nervous System (PNS)

A

Peripheral Nervous System (PNS)
All other nerves
Made up of sensory & motor neurones

Sensory neurones bring information from receptors to the CNS.

Motor neurones carry information from CNS to effectors (muscles & glands).

81
Q

Describe conscious and unconscious Nervous Communication

A

Conscious Nervous Coordination (£5 Drop)

- voluntary
- involves thinking
- uses the brain

Unconscious Nervous Coordination (Simple reflex arc)

- involuntary
- no thinking
- uses spinal cord only
82
Q

Nervous v. Hormonal Response (Differences)

A 
Nervous System
Electrical impulse carried by neurones to specific sites
 Fast response
 Localised effect
short lived

Hormonal response
Hormones carried in the blood all around the body
slow response
(It takes time for hormones to travel in blood (whereas nerve impulse travel quickly).
widespread effect
(Hormones travel to all parts of the body and target cells are dispersed (whereas neurones link directly to specific effectors).
long lasting effect
(Hormones are broken down slowly (whereas neurotransmitters are broken down quickly).

83
Q

What is meant by myogenic control?

A

MYOGENIC CONTROL
The heart initiates its own contractions: electrical impulses start in the SAN (pacemaker) at a set frequency of ~ 70 per minute

84
Q

What is the function of the sinoatrial node?

A

Sends impulses which spread through atria so they contract together to pump blood into ventricles

85
Q

What is the function of the Bundle of His & Purkyne fibres?

A

Conducts impulses through ventricles so they contract together from base upwards, pumping blood into aorta & pulmonary artery

86
Q

What is the function of the Atrioventricular

node (AVN)

A

Relays impulses to ventricles with a slight delay (so ventricles contract after atria), ensuring one-way flow of blood through the heart

87
Q

What is the function of chemoreceptors?

A

Detect changes in

blood CO2, pH & O2

88
Q

What is the function of Sympathetic neurone

A

Impulses along this nerve cause release of noradrenaline

 binds to receptors on SAN increased heart rate

89
Q

What is the function of parasympathetic neurone

A

Impulses along this nerve cause release of acetylcholine

 binds to receptors on SAN decreased heart rate

90
Q

where are baroreceptor and chemoreceptors located?

A

Aorta & carotid artery

91
Q

What is the function of baroreceptors?

A

Detect changes in

blood pressure

92
Q

what happens when chemoreceptors detect
High blood CO2
Low blood pH
Low blood O2

A

Impulses along Sympathetic neurone cause release of noradrenaline binds to receptors on SAN increased heart rate

93
Q

What happens when baroreceptors detect High blood

pressure?

A

Impulses along Sympathetic neurone cause More acetylcholine released  decreased heart rate

94
Q

What are the 7 parts to a homeostatic control mechanism?

A
  1. stimulus
  2. sensor or receptor
  3. afferent path
  4. integrating centre
  5. efferent path
  6. effector
  7. response
95
Q

True or false. Chemoreceptors are sensitive to changes in blood chemistry.

A

True

96
Q

True or false. Peripheral chemoreceptors are located in the aorta and carotid arteries.

A

True

97
Q

True or false. The central chemoreceptor in the medulla oblongata is less powerful than the peripheral chemoreceptors.

A

False

98
Q

True or false. Stretching of alveoli, bronchi and muscles  stretch receptor  Vagus nerve  Medulla Oblongata

A

True

99
Q

True or false. Phrenic nerve  Diaphragm, and Intercostal nerve  Intercostal muscles

A

True

100
Q

True or false. The dive reflex prevents the lungs from overstretching during inhalation.

A

False

101
Q

True or false. Myogenic = muscle cells with pacemaker, intrinsic electrical activity and contraction.

A

True

102
Q

True or false. The Sympathetic nervous system decreases heart rate.

A

False

103
Q

True or false. The Parasympathetic nerve system uses an accelerator nerve and acetylcholine to slow down heart rate.

A

False

104
Q

True or false. Baroreceptors are sensitive to pressure and decrease heart rate when stimulate.

A

True

105
Q

Define Sympathetic system

A

Fight or flight domain of the ANS

106
Q

What is the function of Adrenaline ?

A

Efferent hormone of the SPNS, which increases heart rate and force of contraction

107
Q

Define parasympathetic system.

A

Rest and digest domain of the ANS

108
Q

What is the function of acetylcholine?

A

Efferent hormone of the PSPNS, which decreases heart rate

109
Q

What is the role of the vagus nerve?

A

Efferent nerve of the PSPNS

110
Q

What is the Cardiovascular control centre ?

A

Control centre in the brain which controls heart rate and force of contraction - medulla oblongata

111
Q

In which part of the brain is the cardiovascular centre located?

A

medulla

112
Q

Describe how an impulse reaches the base of the ventricles of the heart from the sinoatrial node.

A

spreads through the atria / right atrium / through cardiac muscle;

to the atrioventricular node;

then through bundle of His / Purkyne fibres;

113
Q

Explain how a rise in blood pressure results in a decrease in the rate of heartbeat.

A

baroreceptors in aorta / carotid arteries;

send impulses to cardiovascular centre / medulla;

which sends impulses along parasympathetic nerves;

to SAN;

(more) acetylcholine released / acetylcholine binds to receptors on SAN to slow it down;

so fewer impulses sent to AVN;

114
Q

Some drugs inhibit the transmission of nerve impulses to the heart. Explain how these drugs reduce high blood pressure

A

Inhibit impulses in sympathetic nerves;

Heart rate lowers because SAN not stimulated
/ because noradrenaline not released;

Human Health and Disease - J (6 decks)

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