TP6 Cardiovascular System Flashcards
(100 cards)
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
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
3
Q
How is blood quality measured
A
Packed Cell Volume (PCV): measures % of RBC’s in the blood
4
Q
List the major components of blood
A
- Erythrocytes (RBC’s)
- Leucocytes (WBC’s)
- Platelets
5
Q
Describe the buffy coat
A
Made up of WBC’s and platelets
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
7
Q
Describe Haematopoiesis
A
Formation and development of all formed elements
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
9
Q
Describe Erythropoiesis
A
Formation of RBC’s
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
11
Q
Name the HGF that stimulates RBC formation
A
Erythropoietin (EPO): released from specific cells in the kidney when under O2 stress
12
Q
Describe the steps in RBC production
A
- Kidneys detect less O2
- When less O2 is delivered to the kidneys, erythropoietin secreted
- Erythropoietin stimulates erythropoiesis by bone marrow
- Additional RBC;s increase O2 carrying capacity
- Increased O2 capacity = initial stimulus relieved
13
Q
Describe the components of RBC’s
A
- Haemoglobin (Hb)
- Carbonic anhydrase
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
15
Q
Describe the function of Hb
A
- Transports O2 as oxyhaemoglobin
- Can also transports CO2 as carbaminohaemoglobin
16
Q
Describe Myoglobin
A
- muscle Hb
- Only has 1x heme group
- Temporary O2 storage
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
18
Q
Describe the role of the spleen in RBC removal
A
Spleen filters, removes, and stores old erythrocytes
19
Q
Describe the role of the liver in RBC removal
A
Metabolises by-products from the breakdown of RBC’s
20
Q
Describe the cause of anaemia
A
Reduction in number of RBC’s, hb, or both
21
Q
Describe the characteristics of Leucocytes
A
- Carry out functions in tissues
- Use circulatory system for transport
- Have nucleus and cytoplasm
22
Q
List the two classifications of leucocytes
A
Granulocytes - with granules in cytoplasm
- Neutrophils
- Eosinophils
- Basophils
Agranulocytes - no granules in cytoplasm
- Monocytes
- Lymphocytes
23
Q
Describe neutrophils
A
- Stain colourless - pale pink
- Multilobulated or segmented nucleus
- First line of defence against infection
24
Q
Describe Eosinophils
A
- Stain bright pink
- Nucleus less lobulated
- Slightly phagocytic
- Respond to allergic reactions and parasitic infections
25
Describe Basophils
- Stain Blue
- Not phagocytic
- Release histamine, heparin, bradykinin during inflammatory reactions
26
Describe Monocytes
- Motile - travel to sites of inflammation
- Develop into very active phagocytic cells known as macrophages
27
Describe Lymphocytes
- Produced from stem cells in bone marrow
- Mature in lymphoid tissues
- Large, round nucleus
28
List the two types of lymphocytes
1. B-lymphocytes (B-cells)
2. T-lymphocytes (T cells)
29
Describe B-lymphocytes
- Mature in bone marrow
- Differentiate into plasma cells that produce antibodies to destroy foreign material
30
Describe T-lymphocytes
- Mature in the Thymus
- Do not produce antibodies
- several types include: cytotoxic T-cells, Helper T-cells, Suppressor T-cells
31
Describe platelets (3 pts)
- 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
32
List the steps in the blood clotting process
1. Vascular phase
2. Platelet phase
3. Coagulation phase
33
Describe the second step of the blood clotting process
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
34
Describe the first step of the blood clotting process
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
35
Describe the third step of the blood clotting process
- Fibrin (protein in plasma), for blood clotting
- Formation of fibrin clot requires reactions called coagulation cascade
36
Describe the components of Plasma
- About 55-75% of blood is plasma
- 92% water, 8% other substances
37
List the functions of plasma proteins
- Transport substances bound by plasma proteins
- Maintain normal blood pressure by contributing to viscosity
38
List three plasma proteins
1. Albumin
2. Globulins
3. Fibrinogen
39
Describe the role of Albumin
- ~60% of plasma proteins
- Regulates blood osmotic pressure
- Binds reversibly & transports main chemicals in blood
40
Describe the role of Fibrinogens
- Produced by the liver
- Essential for clotting process
41
Describe the role of Globulins
- ~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
Describe Serum
- Body fluid
- plasma minus the fibrinogen
- essential for clotting factors
- contains antibodies - for disease prevention and treatment
43
Describe the lymphatic system
- 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
Describe serous fluids
Thin film that decreases friction between apposed surfaces
Inflammation or infection of serous membranes causes increased production of serous fluids
45
List the functions of the cardiovascular system
- 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
Describe the location of the heart
- Cranial to diaphragm
- Left of midline
- Ventral to vertebral column, dorsal to sternum
- 3rd to 6th ribs
47
Describe the pericardium
Double walled sac around the heart composed of:
1. the superficial pericardium
2 deep two layer serous pericardium
48
List the names of the two serous pericardium layers
1. Parietal layer - lines internal surface of heart
2. Visceral layer - lines the surface of the heart
49
Describe coronary circulation
- Blood supply directly to heart muscle
50
Describe the role of heart valves
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
What separates the parietal and visceral layer
Fluid-filled cavity called the pericardial cavity
52
Describe the three layers of the heart wall
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
Describe the two main periods of the cardiac cycle
Systole: ventricle contraction
Diastole: ventricle relaxation
54
Describe the role of Pacemaker cells
Specialised groups of cells for initiating and conducting Ap
55
Describe collateral routes
Ensures blood returns to the heart, even if major vessels are occluded
55
56
Describe cardiac muscle
Striated, short, branched and interconnected - gap junctions
56
57
Describe the role of intercalated discs
Anchor cardiac cells together and allow free passage of ions
57
58
Describe Refractory period
Period in which an excitable membranes responsiveness is totally abolished, meaning it cannot generate another AP
59
List the four stages of cardiac cycle
1. Ventricular filling
2. Isovolumetric ventricular contraction
3. Ventricular ejection
4. Isometric ventricular relaxation
60
Describe the details of 1.ventricular filling
- Pressure atria -> pressure ventricles
- AV valves open
- Passive phase - no atria or ventricular contraction
- Active phase - atria contract
61
Describe the details of 2. Isovolumetric ventricular contraction
- Ventricle contracts - increases pressure
- AV and semilunar valves close
- No blood entering or exiting ventricle
62
Describe the details of 3. Ventricular ejection
- Pressure ventricles -> pressure arteries
- Semilunar valves open
63
Describe the details of 4. Isometric ventricular relaxation
- Ventricle relaxes = decrease pressure
- AV and semilunar valves close
- No blood entering or exiting ventricle
64
What causes heart sounds
Due to turbulent flow when valves close
65
Describe what happens during first heart sound
- AV valves close simultaneously
- Soft lubb
66
Describe what happens during second heart sound
- Semilunar valves close simultaneously
- Louder dubb
67
List the characteristics of Arteries
- Carry blood AWAY from heart
- Thick elastic walls- maintains pressure
- Expands as blood enters (systole)
- Recoil (diastole)
68
List the direction of blood flow
Heart -> Ventricle -> Artery -> Arteriole -> Capillary -> Venule -> Vein
69
Describe the characteristics of Arterioles
- smallest artery
- muscular walls
- regulate blood entering capillary bed
70
Describe the characteristics of Capillaries
- 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
Describe the characteristics of venules
- Smallest veins
- Collect blood from capillary beds
72
Describe the characteristics of veins
- 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
Describe Cardiac Output [CO]
Volume of blood pumped by each ventricle per minute
74
Describe the two factors that influence [CO]
1. Heart rate - no. of beats per min
2. Stroke volume - vol of blood ejected by the ventricle with each beat
75
List the equation to calculate stroke volume
stroke vol = end-diastolic vol - end-systolic vol
76
Describe the factors that influence stroke vol
1. Venous return: squeezing action of the muscles, increases during exercise
2. Sympathetic innervation: increases contractility of the ventricle
77
Describe sympathetic innervation and how it works
Increases heart rate - by making pacemaker or SA node fire faster
78
What controls the SA node
B-adrenoreceptors: receptor proteins embedded in the cell membrane - activated by adrenaline and nor- adrenaline
79
Describe parasympathetic innervation
Decreases heart rate - heart rate slows when K+ is detected in heart cells
80
Name the nerve regulating heart rate, cardiac output
Vagus nerve
81
Describe blood pressure
- The force exerted on the wall of the blood vessels by the blood - mmHg (mm of mercury)
- Pulsatile
82
Describe systolic blood pressure
- maximum pressure
- 120 mmHg
83
Describe diastolic blood pressure
- minimum pressure
- 80 mmHg
84
Describe Pulse Pressure
- Difference between systolic and diastolic pressure
- 40 mmHg
85
Describe Mean Arterial Pressure
Average level of the blood pressure over several heart beats
86
Describe Peripheral resistance
The amount of friction the blood encounters as it passes along vessels
86
List the factors impacting peripheral resistance
- 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
List two factors that influence mean arterial pressure (MAP)
1. Cardiac Output
2. Total Peripheral Resistance
87
What factors control MAP?
Short and long term regulation
88
Describe short term regulation in MAP
- Regulates [CO] and TPR
- Involves heart and blood vessels
- Primary, neural and chemical control
89
Describe long term regulation in MAP
- Regulate blood volume
- Involves Kidneys
- Primarily hormonal control
90
Describe autoregulation of blood flow
Capacity of tissues to regulate their own blood flow and keep it constant
90
Describe neural control of MAP
- 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
Describe the relationship between blood flow velocity and pressure
Velocity of blood flow is dependent on blood pressure
- Higher pressure = greater blood flow
91
List the two major mechanisms of autoregulation of blood flow
1. Metabolic control
2. Myogenic control
92
Describe myogenic control
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
Describe metabolic control
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
