Intro to CVS and general principles Flashcards

1
Q

What are the functions of the CVS?

A
  • Transport
  • defence
  • haemostasis
  • thermoregulation
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2
Q

What does the CVS transport?

A
  • O2 and substates to cells
  • CO2 and metabolites from cells
  • hormones and drugs around the body
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3
Q

How does the CVS function as a defence?

A
  • immune cells and molecules in the blood
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4
Q

How does the CVC function in haemostasis?

A
  • blood clotting mechanism (platelets and blood vessel walls)
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5
Q

Hoe does the CVS function in thermoregulation?

A
  • vasodilation/constriction to dissipate/conserve heat
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6
Q

The CVS is also involved in transmission of pressure - where is an example of this?

A
  • like filtration of substrates in the kidneys
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7
Q

What are the components of the CVS?

A
  • heart (pump)
  • blood vessels (transport)
  • blood
  • spleen
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8
Q

The blood is a central components of the CVS what is it made up of?

A
  • solid (cells) including red and white blood cells (45%)
  • fluids (plasma) = 55%
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9
Q

What is the spleen and what does it do within the CVS?

A
  • large flat organ caudal to diaphragm
  • stores and filters blood
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10
Q

What can horses and dogs do to their spleens?

A
  • the spleen can contract to shunt blood into CVS if required
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11
Q

There are 4 chambers in the mammal heart what are these chambers?

A
  • 2 atria “primer” pumps
  • 2 ventricles “power” pumps
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12
Q

How is contraction controlled?

A
  • controlled by an intrinsic pacemaker, and regulated by the autonomic nervous system
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13
Q

Describe heart rate in larger species and smaller species and how it can be affected?

A
  • lower in larger species
  • higher in smaller species
  • can be breed specific
  • can be health related
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14
Q

Describe arteries and what do they do?

A
  • smooth muscle and elastic walls to prevent inferences with blood flow and are able to stretch
  • carry blood away from the heart to the body or lungs
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15
Q

Describe capillaries and what do they do?

A
  • very thin walls (endothelial cells only)
  • exchange of gases and substrates with tissues
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16
Q

Describe veins and what do they do?

A
  • less muscular than arteries as they carry blood at a lower pressure
  • carry blood back to the heart
  • also blood reservoirs (blood rests in veins)
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17
Q

Evolutionary the heart is derived from what?

A
  • a simple pulsating pipe
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18
Q

In adult mammals (+ birds and crocs) the heart has developed what?

A
  • septa to divide it into 4 chambers
  • separate systemic and pulmonary circuits so the blood doesn’t mix between the two
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19
Q

What is the fish heart like?

A
  • single atrium and ventricle
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20
Q

What is an amphibian heart like?

A
  • 2 atria , 1 ventricle
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21
Q

What are lizard and chelonians hearts like?

A
  • 2 atria, 1 ventricle with incomplete septa
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22
Q

The mammalian heart is a dual circulatory system - where does blood coming from the body enter?

A
  • cranial vena cava
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23
Q

Where does blood coming from the veins enter?

A
  • the pulmonary veins
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24
Q

Where does blood going towards the lungs exit?

A
  • pulmonary arteries
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25
Where does blood going to the body exit?
- the aorta
26
Due to the heart having a dual circulatory system - what type of circulation does the left side of the heart have?
- systemic circulation (from the left ventricle)
27
Describe the left side of the heart:
- blood to and from the body - high pressure (120/80 systolic/diastolic - in humans) - oxygenated blood
28
Describe the right side of the heart:
- Pulmonary circulation (from right ventricle) - blood to and from lungs - lower pressure (e.g. 25/8 systolic/diastolic) - deoxygenated blood
29
What does systolic mean and what is its effect on blood pressure?
- ventricles contracting so pressure is higher
30
What does diastolic mean and what is its effect on blood pressure?
- ventricles relaxing so pressure is lower
31
What does the apex of the heart mark?
- the left ventricle
32
What externally separates the chambers of the heart?
- fat filled groove (paraconal groove)
33
What supplies the heart muscle externally?
- coronary arteries
34
Where are the atria found?
- above the ventricles
35
What are the atria covered by?
- by atrial appendages = auricles (small sacs, expansions)
36
Where is the base of the heart found?
- base of the heart is where it is anchored by blood vessels = the top of the heart
37
Where do the cranial and caudal vena cava enter?
- the right atrium
38
Where does the pulmonary artery emerge from?
- the right ventricle
39
Where do the pulmonary veins enter?
- enters the left atrium
40
Where the the aorta emerge from?
- from the left ventricle
41
What is the myocardium?
- muscle wall of heart
42
What is the endocardium?
- Thin layer of cells lining internal surface, continuous with endothelium of blood vessels
43
What is the sac called around the heart called?
- pericardial sac
44
What is the function of the pericardial sac?
- functions to aid heart beating in reducing friction
45
What do the valves in the heart function to do?
- to prevent back flow
46
What are the atrio-ventricular (inlet valves to ventricles) called?
- mitral value - tricuspid valve
47
What are semi-lunar valves (outlet valves from ventricles) called?
- pulmonary - aortic
48
What are AV valved anchored by and what does this prevent?
- by chordae tendinae (heart strings) and papillary muscles - prevents them flapping the wrong way
49
What valves are located on the left side of the thoracic cavity?
- pulmonary valve - aortic valve - mitral
50
How can location of heart valves help in diagnosis?
- help locate murmurs
51
What is the cardiac skeleton and what is its function?
- fibrous ridged structure - Holds cardiac shape and anchors structures - electrically separate compartments (breaks up muscle continuity between atria and ventricles)
52
What arteries are the first to branch from the aorta?
- the coronary arteries
53
How much of the cardiac output is delivered directly to the myocardium?
- 5%
54
There is extensive what of the myocardium?
- extensive capillarisation
55
What do elastic vessels (large arteries) do?
- Accommodate stroke volume (high elastance) - convert intermittent ejection (stop-go -flow) into continuous flow
56
What do conduit and feed vessels (medium to small arteries) do?
- conduct blood flow to organs
57
What do resistance vessels (arterioles, terminal arteries) do?
- control arterial blood pressure - control local blood flow
58
What do exchange vessels (capillaries) do?
- nutrient delivery to cells - lymph formation - removal of metabolic wate
59
What do capacitance vessels (venules, veins) do?
- control cardiac filling pressure - reservoir of blood
60
What are the 3 layers of the blood vessel?
- tunica intima - tunica media - tunica adventitia
61
Describe the tunica intima:
- flattened layer of endothelial cells plus basement membrane - continuous with endocardium of the heart
62
Describe the tunic media:
- smooth muscle cells, internal and eternal elastic laminae
63
Describe the tunica adventitia:
- loose connective tissue, vasa vasorum
64
What is the difference in the appearance of a artery and vein walls historically?
- arteries have thick walls - veins have thin walls
65
What is the difference between the tunica intima in an artery vs a vein?
- artery = rippled, internal elastic membrane present - vein = smooth looking, internal elastic membrane absent
66
What are the differences between the tunica medias in arteries vs veins?
- smooth muscle cells in both - Artery = thick, elastic , external elastic membrane present - Vein = thin, collagen fibres, external elastic membrane absent
67
What are the similarities in the tunica adventitia in both veins and arteries?
- collage, elastic fibres, nerve terminals in both
68
What layer is only present in the capillaries?
- only have tunica intima
69
What are capillaries?
- endothelium supported by basement membrane
70
What do some capillary beds contain?
- pericytes
71
What is the function of a pericyte in a capillary bed?
- supportive - contractile
72
There are several types of capillary - what are these?
- continuous (one endothelium sitting on basement membrane) - fenestrated (Kidney - glomerulus) - Sinusoidal (spleen)
73
Why are veins used as reservoirs and how much of blood is at rest?
- large volume of blood can be accommodated in veins so 2/3rds of blood volume is at rest
74
The amount of blood in reservoir veins can be altered based in physiological need - give an example:
- haemorrhage or exercise > contraction under sympathetic influence
75
The functions of the cardiovascular system are due to what?
- due to blood flow through body via vessels
76
Fluid flow (F - volume of fluid transported through a tube per time) is determined by what?
- pressure difference between tube ends ( put triangle here P) - resistance to flow (R)
77
What is the equation for volume of fluid transported through a tube per unit of time (F)?
F = triangle P / R
78
The same pressure does what to the flow?
- the same pressure = same flow
79
Where does resistance to flow come from?
- Resistance to flow comes from the fluid molecules/particles moving against each other and the fluid moving against the vessel walls
80
What causes resistance?
- The viscosity (n) of the fluid - the length (L) of the tube - the radius (r) of the tube (more important)
81
What is the equation for resistance (R)?
R = nL/r4
82
What happens as vessels branch?
- there is an increase in total cross-section
83
At what vessel can we act to change resistance in blood flow?
- the arterioles
84
Where does most resistance come from?
- comes from arterioles (many tubes of small radius)
85
What does the changing of radius of arterioles have a big impact on?
- has a big impact on blood flow to tissues (vasodilation, vasoconstriction)
86
What vessels is flow slowest in?
- flow slowest in capillaries (site of exchange)
87
As well as molecules what is also exchanged across capillary walls?
- fluid
88
Two opposing pressures cause fluid movement across the capillary wall - what are these pressures?
- Hydrostatic pressure exerted by fluid - oncotic pressure exerted by proteins
89
The balances of both hydrostatic and oncotic forces determine what?
- determines net fluid movement
90
What are starling forces?
- they are hydrostatic pressures
91
In hydrostatic pressures at the input (arterial) end - capillary hydrostatic force is what?
- is high = net outward hydrostatic force
92
In hydrostatic pressure at the output (venous) end, capillary hydrostatic pressure is what?
- pressure is lower = net inward hydrostatic force
93
What do hydrostatic forces create along the vessel?
- create a gradient along the vessel
94
In oncotic pressure at the input (arterial) end, capillary oncotic force is what?
- is low = net outward oncotic force
95
In oncotic forces at the output end (venous) capillary oncotic pressure is what?
- higher = net inward oncotic force
96
What do oncotic pressure create along a vessel?
- create a gradient along the vessel
97
The balance of forces along a vessel determines what?
- movement
98
The net effect of the four starling forces results in what fluid movements?
- outward (filtration) - inwards (reabsorption)
99
Every tissues has a difference in balance of forces depending on what?
- the anatomy and function of the tissue
100
What is the general rule for fluid filtering and reabsorption in tissue?
- generally in tissue more fluid is filtered than is reabsorbed
101
Well-perfused capillaries filter fluid what happens to their filtration rate along the vessel?
- filtration rate decreases along the vessel
102
The composition of lymph is similar to the composition of what?
- interstitial fluid
103
Excess lymph drains where?
- into lymphatic vessels
104
Where do lymphatic vessel carry interstitial fluid?
- back into the bloodstream
105
Lymph travels through progressively larger lymphatic vessels until they are emptied where?
- back into venous circulation
106
Lymph may travel through what node?
- lymph nodes
107
Where does the thoracic duct commonly drain into?
- left branches of vena cava (left jugular, subclavian, brachiocephalic veins)
108
Some conditions can result in abnormal accumulation of interstitial fluid (oedema) via what?
- increased capillary pressure - decreased circulating plasma protein (decreases absorption) - increased capillary permeability (inflammation) - decreased lymphatic drainage (blockage)