TP6 Cardiovascular System Flashcards

1
Q

Lists the products blood transports

A

Carries:
- Nutrients from digestive tract and liver to body
tissues
- O2 from lungs to peripheral tissues and CO2 from
peripheral tissues to lungs
- Hormones from endocrine glands to target organs
and tissues
- Waste products from various tissues to kidneys for
excretion

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2
Q

List the other functions of blood

A
  • heat and assists in thermoregulation
  • regulates pH and ion composition of interstitial fluids
  • Clots to restrict fluid loss and begin injury repair
  • defends against toxins and pathogens
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3
Q

How is blood quality measured

A

Packed Cell Volume (PCV): measures % of RBC’s in the blood

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4
Q

List the major components of blood

A
  • Erythrocytes (RBC’s)
  • Leucocytes (WBC’s)
  • Platelets
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5
Q

Describe the buffy coat

A

Made up of WBC’s and platelets

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6
Q

Describe the properties of blood

A

viscosity: 5x the amount of water
temp: slightly above that of the body
pH: slightly alkaline (7.4 +/- 0.05)
volume: 8-10% lean body weight of animal

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7
Q

Describe Haematopoiesis

A

Formation and development of all formed elements

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8
Q

Describe RBC’s (5 pts)

A
  • No nuclei or mitochondria
  • Most abundant cells in blood
  • Can distort temporarily and elastically to pass through small capillaries
  • specialised for O2 transport
  • Shape provides larger S.A.:V = faster O2 exchange across cell membrane
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9
Q

Describe Erythropoiesis

A

Formation of RBC’s

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10
Q

Where are RBC’s formed in adults and foetus?

A

In adults, RBC’s are formed in the red bone marrow, and in a foetus, RBC’s are formed in bone marrow, liver, spleen and lymph nodes

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11
Q

Name the HGF that stimulates RBC formation

A

Erythropoietin (EPO): released from specific cells in the kidney when under O2 stress

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12
Q

Describe the steps in RBC production

A
  1. Kidneys detect less O2
  2. When less O2 is delivered to the kidneys, erythropoietin secreted
  3. Erythropoietin stimulates erythropoiesis by bone marrow
  4. Additional RBC;s increase O2 carrying capacity
  5. Increased O2 capacity = initial stimulus relieved
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13
Q

Describe the components of RBC’s

A
  • Haemoglobin (Hb)
  • Carbonic anhydrase
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14
Q

Describe the structure of Hb

A
  • 4x red porphyrin pigments (heme) - gives cells red colour
  • Each heme group contains Fe atom - combines loosely with O2 molecule
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15
Q

Describe the function of Hb

A
  • Transports O2 as oxyhaemoglobin
  • Can also transports CO2 as carbaminohaemoglobin
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16
Q

Describe Myoglobin

A
  • muscle Hb
  • Only has 1x heme group
  • Temporary O2 storage
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17
Q

Describe the steps in the removal of RBC’s

A
  • Broken down by macrophages in the spleen and liver
  • Hb broken down into heme and globin
  • Fe separated from heme
  • Heme then converted to biliverdin (green pigment), then bilirubin (yellow pigment)
  • Excreted in bile or urine
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18
Q

Describe the role of the spleen in RBC removal

A

Spleen filters, removes, and stores old erythrocytes

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19
Q

Describe the role of the liver in RBC removal

A

Metabolises by-products from the breakdown of RBC’s

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20
Q

Describe the cause of anaemia

A

Reduction in number of RBC’s, hb, or both

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21
Q

Describe the characteristics of Leucocytes

A
  • Carry out functions in tissues
  • Use circulatory system for transport
  • Have nucleus and cytoplasm
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22
Q

List the two classifications of leucocytes

A

Granulocytes - with granules in cytoplasm
- Neutrophils
- Eosinophils
- Basophils
Agranulocytes - no granules in cytoplasm
- Monocytes
- Lymphocytes

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23
Q

Describe neutrophils

A
  • Stain colourless - pale pink
  • Multilobulated or segmented nucleus
  • First line of defence against infection
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24
Q

Describe Eosinophils

A
  • Stain bright pink
  • Nucleus less lobulated
  • Slightly phagocytic
  • Respond to allergic reactions and parasitic infections
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25
Q

Describe Basophils

A
  • Stain Blue
  • Not phagocytic
  • Release histamine, heparin, bradykinin during inflammatory reactions
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26
Q

Describe Monocytes

A
  • Motile - travel to sites of inflammation
  • Develop into very active phagocytic cells known as macrophages
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27
Q

Describe Lymphocytes

A
  • Produced from stem cells in bone marrow
  • Mature in lymphoid tissues
  • Large, round nucleus
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28
Q

List the two types of lymphocytes

A
  1. B-lymphocytes (B-cells)
  2. T-lymphocytes (T cells)
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29
Q

Describe B-lymphocytes

A
  • Mature in bone marrow
  • Differentiate into plasma cells that produce antibodies to destroy foreign material
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30
Q

Describe T-lymphocytes

A
  • Mature in the Thymus
  • Do not produce antibodies
  • several types include: cytotoxic T-cells, Helper T-cells, Suppressor T-cells
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31
Q

Describe platelets (3 pts)

A
  • No nuclei
  • In non-mammalian vertebrates, are nucleated, called thrombocytes
    In adult mammal, originate from megakaryocytes, by budding off pieces of cytoplasm
  • Important in blood clotting
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32
Q

List the steps in the blood clotting process

A
  1. Vascular phase
  2. Platelet phase
  3. Coagulation phase
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33
Q

Describe the second step of the blood clotting process

A
  1. Platelets attach to the sticky endothelial membranes forming platelet plug
    - Platelets contain high conc. of actin and myosin
    More platelets aggregate = tightening of plug
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34
Q

Describe the first step of the blood clotting process

A
  1. Damage to blood vessel wall = contraction of smooth muscle fibres (vascular spasm)
  2. Activation of sympathetic nervous system = further vasoconstriction
  3. Endothelial cells release specific chemical factors and local hormones
  4. Endothelial cells become sticky to platelets
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35
Q

Describe the third step of the blood clotting process

A
  • Fibrin (protein in plasma), for blood clotting
  • Formation of fibrin clot requires reactions called coagulation cascade
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36
Q

Describe the components of Plasma

A
  • About 55-75% of blood is plasma
  • 92% water, 8% other substances
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37
Q

List the functions of plasma proteins

A
  • Transport substances bound by plasma proteins
  • Maintain normal blood pressure by contributing to viscosity
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38
Q

List three plasma proteins

A
  1. Albumin
  2. Globulins
  3. Fibrinogen
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39
Q

Describe the role of Albumin

A
  • ~60% of plasma proteins
  • Regulates blood osmotic pressure
  • Binds reversibly & transports main chemicals in blood
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40
Q

Describe the role of Fibrinogens

A
  • Produced by the liver
  • Essential for clotting process
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41
Q

Describe the role of Globulins

A
  • ~35% of plasma proteins
  • Enzymatic functions
  • α & B globulins produced by the liver
  • Gamma globulins produced by lymphocytes & plasma cells - in response to stimulation by antigens
42
Q

Describe Serum

A
  • Body fluid
  • plasma minus the fibrinogen
  • essential for clotting factors
  • contains antibodies - for disease prevention and treatment
43
Q

Describe the lymphatic system

A
  • Extensive network of one-way vessels
  • small vessels -> large vessels -> join with large veins cranial to the heart
  • Small leakage of protein and fluid from capillaries is lymph
44
Q

Describe serous fluids

A

Thin film that decreases friction between apposed surfaces
Inflammation or infection of serous membranes causes increased production of serous fluids

45
Q

List the functions of the cardiovascular system

A
  • Transport and distribute essential substances to cells
  • Move metabolic waste from cells to lung, liver and kidneys
  • Move hormones, immune cells, and clotting protein to specific target cells
  • Homeostasis: thermoregulation and change in O2 and nutrient supply
46
Q

Describe the location of the heart

A
  • Cranial to diaphragm
  • Left of midline
  • Ventral to vertebral column, dorsal to sternum
  • 3rd to 6th ribs
47
Q

Describe the pericardium

A

Double walled sac around the heart composed of:
1. the superficial pericardium
2 deep two layer serous pericardium

48
Q

List the names of the two serous pericardium layers

A
  1. Parietal layer - lines internal surface of heart
  2. Visceral layer - lines the surface of the heart
49
Q

Describe coronary circulation

A
  • Blood supply directly to heart muscle
50
Q

Describe the role of heart valves

A

Ensure unidirectional blood flow
- Atrioventricular valves (AV) prevent backflow into the atria when the ventricles contract
- Semilunar valves prevent backflow of blood into ventricles

51
Q

What separates the parietal and visceral layer

A

Fluid-filled cavity called the pericardial cavity

52
Q

Describe the three layers of the heart wall

A
  1. Epicardium: serous membrane lining smooth outer surface of heart
  2. Myocardium: middle layer, cardiac muscle cell for heart contraction
  3. Endocardium: smooth inner surface of heart chambers
53
Q

Describe the two main periods of the cardiac cycle

A

Systole: ventricle contraction
Diastole: ventricle relaxation

54
Q

Describe the role of Pacemaker cells

A

Specialised groups of cells for initiating and conducting Ap

55
Q

Describe collateral routes

A

Ensures blood returns to the heart, even if major vessels are occluded

55
Q
A
56
Q

Describe cardiac muscle

A

Striated, short, branched and interconnected - gap junctions

56
Q
A
57
Q

Describe the role of intercalated discs

A

Anchor cardiac cells together and allow free passage of ions

57
Q
A
58
Q

Describe Refractory period

A

Period in which an excitable membranes responsiveness is totally abolished, meaning it cannot generate another AP

59
Q

List the four stages of cardiac cycle

A
  1. Ventricular filling
  2. Isovolumetric ventricular contraction
  3. Ventricular ejection
  4. Isometric ventricular relaxation
60
Q

Describe the details of 1.ventricular filling

A
  • Pressure atria -> pressure ventricles
  • AV valves open
  • Passive phase - no atria or ventricular contraction
  • Active phase - atria contract
61
Q

Describe the details of 2. Isovolumetric ventricular contraction

A
  • Ventricle contracts - increases pressure
  • AV and semilunar valves close
  • No blood entering or exiting ventricle
62
Q

Describe the details of 3. Ventricular ejection

A
  • Pressure ventricles -> pressure arteries
  • Semilunar valves open
63
Q

Describe the details of 4. Isometric ventricular relaxation

A
  • Ventricle relaxes = decrease pressure
  • AV and semilunar valves close
  • No blood entering or exiting ventricle
64
Q

What causes heart sounds

A

Due to turbulent flow when valves close

65
Q

Describe what happens during first heart sound

A
  • AV valves close simultaneously
  • Soft lubb
66
Q

Describe what happens during second heart sound

A
  • Semilunar valves close simultaneously
  • Louder dubb
67
Q

List the characteristics of Arteries

A
  • Carry blood AWAY from heart
  • Thick elastic walls- maintains pressure
  • Expands as blood enters (systole)
  • Recoil (diastole)
68
Q

List the direction of blood flow

A

Heart -> Ventricle -> Artery -> Arteriole -> Capillary -> Venule -> Vein

69
Q

Describe the characteristics of Arterioles

A
  • smallest artery
  • muscular walls
  • regulate blood entering capillary bed
70
Q

Describe the characteristics of Capillaries

A
  • Branch from arterioles
  • Thinnest in diameter - 1x RBC thick
  • Allows exchange between plasma and interstitial fluid
  • Walls not muscular - therefore cannot dilate or contract
71
Q

Describe the characteristics of venules

A
  • Smallest veins
  • Collect blood from capillary beds
72
Q

Describe the characteristics of veins

A
  • Thin walled
  • Collect blood from venules
  • Low blood pressure!!
  • Blood returns to the heart with the help f contracting skeletal muscle
  • No pulse
  • Blood flow regulated by valves
73
Q

Describe Cardiac Output [CO]

A

Volume of blood pumped by each ventricle per minute

74
Q

Describe the two factors that influence [CO]

A
  1. Heart rate - no. of beats per min
  2. Stroke volume - vol of blood ejected by the ventricle with each beat
75
Q

List the equation to calculate stroke volume

A

stroke vol = end-diastolic vol - end-systolic vol

76
Q

Describe the factors that influence stroke vol

A
  1. Venous return: squeezing action of the muscles, increases during exercise
  2. Sympathetic innervation: increases contractility of the ventricle
77
Q

Describe sympathetic innervation and how it works

A

Increases heart rate - by making pacemaker or SA node fire faster

78
Q

What controls the SA node

A

B-adrenoreceptors: receptor proteins embedded in the cell membrane - activated by adrenaline and nor- adrenaline

79
Q

Describe parasympathetic innervation

A

Decreases heart rate - heart rate slows when K+ is detected in heart cells

80
Q

Name the nerve regulating heart rate, cardiac output

A

Vagus nerve

81
Q

Describe blood pressure

A
  • The force exerted on the wall of the blood vessels by the blood - mmHg (mm of mercury)
  • Pulsatile
82
Q

Describe systolic blood pressure

A
  • maximum pressure
  • 120 mmHg
83
Q

Describe diastolic blood pressure

A
  • minimum pressure
  • 80 mmHg
84
Q

Describe Pulse Pressure

A
  • Difference between systolic and diastolic pressure
  • 40 mmHg
85
Q

Describe Mean Arterial Pressure

A

Average level of the blood pressure over several heart beats

86
Q

Describe Peripheral resistance

A

The amount of friction the blood encounters as it passes along vessels

86
Q

List the factors impacting peripheral resistance

A
  • Diameter of the vessels: narrow = greater resistance
  • Vessel length: longer = greater resistance
  • Smoothness: rougher = turbulence and decreased blood flow
  • Blood viscosity: thicker blood = slower flow
87
Q

List two factors that influence mean arterial pressure (MAP)

A
  1. Cardiac Output
  2. Total Peripheral Resistance
87
Q

What factors control MAP?

A

Short and long term regulation

88
Q

Describe short term regulation in MAP

A
  • Regulates [CO] and TPR
  • Involves heart and blood vessels
  • Primary, neural and chemical control
89
Q

Describe long term regulation in MAP

A
  • Regulate blood volume
  • Involves Kidneys
  • Primarily hormonal control
90
Q

Describe autoregulation of blood flow

A

Capacity of tissues to regulate their own blood flow and keep it constant

90
Q

Describe neural control of MAP

A
  • Occurs through baroreceptors - pressure receptors - AKA stretch receptors
  • Important for short term regulation of blood pressure
  • Responds to stretch due to pressure changes in arteries
90
Q

Describe the relationship between blood flow velocity and pressure

A

Velocity of blood flow is dependent on blood pressure
- Higher pressure = greater blood flow

91
Q

List the two major mechanisms of autoregulation of blood flow

A
  1. Metabolic control
  2. Myogenic control
92
Q

Describe myogenic control

A
  1. When BP increases, blood flow increases
  2. When blood flow increases, smooth muscle present stretches
  3. Stretch acts as stimulus to the muscle
  4. Muscle responds by contraction
  5. Contraction = narrowing of lumen
  6. Decreased lumen = increase in resistance to blood flow
  7. Restricts the increase in blood flow
93
Q

Describe metabolic control

A
  1. Decrease BP and blood flow to a tissue results in;
  2. Decreased arterial flow and decreased venous outflow
  3. Leads to accumulation of products of metabolism
  4. Metabolites are vasodilators, and act on organ vessels to dilate
  5. Blood flow increased and returns back to normal