Anatomy of the CV system 2 Flashcards
1
Q
What are the components of the CV system?
A
- Heart
- Arteries
- Capillaries
- Veins
2
Q
What is the main function of the heart?
A
Pump
3
Q
What is the main function of the arteries?
A
Distribution from the heart
4
Q
What is the main function of the capillaries?
A
Main exchange site for nutrients, gases
5
Q
What is the main function of the veins?
A
Collect and return to heart
6
Q
What are the 3 layers of the heart?
A
- Endocardium
- Myocardium
- Ectoderm
7
Q
What is the endocardium composed of?
A
- Epithelium
- Basement membrane
- Connective tissue
8
Q
What is the myocardium composed of?
A
Cardiac muscle
9
Q
What is the epicardium composed of?
A
- Connective tissue
- Basement membrane
- Epithelium
10
Q
What are the 3 layers found in blood vessels?
A
- Tunica intima
- Tunica media
- Tunica adventitia
11
Q
What is the tunica intima composed of?
A
- Simple squamous epithelium
- Basement membrane
- Connective tissue
12
Q
What is the tunica media composed of?
A
- Smooth muscle tissue
- Elastic tissue
13
Q
What is the tunica adventitia composed of?
A
-Fibrous connective tissue
14
Q
What generalisations can be made about arteries?
A
- Arteries are smaller in diameter than their accompanying vein
- Arteries have thicker walls than their accompanying vein
15
Q
How does the thickness of the tunica adventitia and media differ between arteries and veins?
A
- Arteries have a thick media, thin adventitia
- Veins have a thin media, thick adventitia
16
Q
How does diameter vary across blood vessels?
A
Arteries > arterioles > capillaries
17
Q
How does the total cross-sectional area vary across blood vessels?
A
Arteries< arterioles< capillaries
18
Q
What are the 3 types of artery?
A
- Elastic
- Muscular
- Arterioles
19
Q
Describe elastic arteries.
A
Large conducting
20
Q
Give 3 examples of elastic arteries.
A
- Aorta
- Common carotid
- Pulmonary
21
Q
Describe muscular arteries.
A
Distributing arteries
22
Q
Give 3 examples of muscular arteries.
A
- Coronary arteries
- Radial
- Femoral
23
Q
What are arterioles?
A
Terminal branches which supply blood to capillary bed
24
Q
What happens to elastic arteries during systole?
A
Stretched
25
What do elastic arteries act as?
Pressure reservoirs
26
What happens to elastic arteries during diastole?
- During diastole the heart relaxes which leads to a fall in pressure.
- The artery recoils thereby maintaining pressure on the blood
27
What is the recoil and stretchability of elastic arteries due to?
The presence of extensive amounts of elastic fibres in T. media in the form of layers called laminae
28
What secretes elastic fibres?
Smooth muscle
29
What do muscular arteries do?
Control distribution of blood to regions
30
What does the thick T. media of muscular arteries contain?
Smooth muscle cells
31
What cannot be found between the muscle cells in the T. media of muscular arteries?
Elastic lamina
32
How are elastic fibres arranged in muscular arteries?
-Elastic fibres are concentrated in 2 well defined sheets call the internal elastic lamina (IEL) just under the epithelium and the thin outer elastic lamina (OEL) between T media and T adventitia
33
What happens to the smaller muscular arteries?
The gradually change histologically to become arterioles
34
What is lacking in arterioles?
- IEL
| - T adventitia
35
What are arterioles composed of?
- Endothelium
| - Basement membrane
36
How many layers of smooth muscle are there in the T media of arterioles?
1-2 layers
37
What do arterioles control?
- Local: control blood flow to capillary beds
| - Systemic: control blood pressure
38
What is lacking in capillaries?
- T media
| - T adventitia
39
What are capillaries composed of?
- Endothelium
| - Basement membrane
40
What are pericytes?
Incomplete layer of cells surrounding basement membrane. They have contractile properties which help control flow of blood in the capillaries
41
Why is blood pressure in the capillaries low?
The sum of diameters of all capillaries in the body> diameter of the aorta
42
What property of capillaries make them suited to their function?
Thin walled
43
What is the only layer that capillaries have?
T intima
44
What are the 3 types of capillaries?
- Continuous
- Fenestrated
- Discontinuous
45
What are continuous capillaries responsible for?
Selective transport mechanisms
46
Where are continuous capillaries found?
Muscle
47
What can continuous capillaries control?
Can control what is exchanged
48
How does material pass through continuous capillaries?
Material must pass trough cells or between cells (junctions can control)
49
How are fenestrated capillaries characterised?
- Have fenestrations (or pores)
| - With or without protein diaphragms
50
What do protein diaphragms do in fenestrated capillaries?
Filter molecules by MW &/or charge
51
Where are fenestrated capillaries found?
- Endocrine glands
| - Kidney renal corpuscle
52
How are discontinuous capillaries characterised.
Contain gaps between endothelial cells (and basement membrane)
53
What do the gaps in discontinuous capillaries allow?
Free passage of fluid and cells
54
Where are discontinuous capillaries found?
- Liver
- Spleen
- Bone marrow
55
What are sinusoids?
Large diameter discontinuous capillaries
56
Where are sinusoids found?
Where large amounts of exchange takes place:
- Liver
- Some endocrine glands
57
What does the T intima of sinusoids contain?
Phagocytic cells
58
What do arteriovenous shunts do?
Bypass capillary beds
59
When do AV shunts occur?
Skin in thermoregulation
60
What are the blood vessels involved in the venous system?
- Capillary bed
- Small venule
- Small/medium sized vein
- Large vein
61
What is the structure of veins?
- T intima is thin
- IEL and OEL thin or absent
- T media is very thin or absent
- T adventitia - collagenous tissue
- Valves
62
What is the purpose of valves in the venous system?
To prevent back flow
63
How to valves present in veins?
As endothelial projections into the lumen
64
Where is the difference between superficial and deep veins most obvious?
Lower limb
65
Describe superficial veins.
- Thick walled
| - No surrounding support
66
Describe deep veins.
- Thin walled
| - Surrounding support from deep fascia and muscles
67
Where are deep veins usually found?
-Deep veins lie next to their corresponding artery and are often found near the bone
68
What is the fate of superficial veins?
Ultimately drain into deep veins
69
What does the lymphatic system do?
Drains tissue fluid lost from blood capillaries
70
What happens after fluid travels through the lymphatic system?
It drains into the systemic venous system
71
Where are lymph nodes found?
Nodes found alongside major veins and around origins of major arteries
72
What do valves in the lymphatic system do?
Direct flow
73
What is the lymphatic system clinically important in?
Tumour cell metastases
74
What are lymph capillaries lined by?
Very thin endothelium
75
What kind of capillaries are lymph capillaries?
Blind ended
76
What is absent in lymph capillaries?
- Fenestrations
- Absent/ rudimentary basal lamina
- RBC
77
What pressure maintains the lumen of lymph capillaries?
Negative hydrostatic pressure
78
What is the role of anchoring filaments in lymph capillaries?
Fine collagenous filaments link endothelial cell to surrounding tissue keeping lumen open
79
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