Structure of Blood Vessels- 1 Flashcards Preview

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Flashcards in Structure of Blood Vessels- 1 Deck (24):
1

Left Ventricle
Function:
Mean pressure:
Structural features:

Function: pump
Mean pressure: 95 mmHg
Structural features thick muscular walls, inlet & outlet valves

2

Large arteries
Function:
Structural features:

Function: Conducting, dampen flow

Structural features: elastic fibres

3

Medium-sized arteries
Function:
Mean pressure:
Structural features

Function: distributing, push blood to areas of demand

Mean pressure: 95-85 mmHg

Structural features: muscular walls to control diameter + CT for strength

4

Arterioles, metarterioles, precapillary sphincters
Function:
Mean pressure:
Structural features

Function: control pressure flow
Mean pressure: 85-35
Structural features: smooth muscle to control diameter, little CT

5

Capillaries
Function:
Mean pressure:
Structural features:

Function: slowed flow for gas/nutrient exchange
Mean pressure: 35-15
Structural features: endothelium, no muscle or CT

6

Venules
Function:
Mean pressure:
Structural features:

Function: collecting vessels (small veins)
Mean pressure: 15-0
Structural features: thin walled, large diameter

7

Veins
Mean Pressure:
Structural Features:

Mean Pressure: Low
Structural Features: Thin walled, variable structure, valves to assist return

8

Right Atrium
Mean Pressure:
Structural Features:

Mean Pressure: 0-2
Structural Features: Thin, muscular walls

9

The collecting system makes up __% of Blood volume

70%

10

Elastic arteries

The aorta and pulmonary arteries, which occur jsut downstream of the ventricles.
They fuction to store blood during 'Ventricular ejection' or systole, then recoil during ventricular filling (diastle), to ensure steady blood flow from the heart.

11

Elastic Arteries:
Tunica Adventitia

Usual collagen(restraint) and elastic fibres, small blood vessels "vasavasorum" and autonomic nerves

12

Elastic Arteries:
Tunica Media

Well defined. Many lamellar units (50-60 in aorta). Each unit is made up of an elastic lamina, smooth muscle and collagen fibres. These run mainly in a circular orientation around the vessel

**smooth muscle has little effect due to large lumen

13

Elastic Arteries:
Tunica Intima

Well defined. Thicker than in muscular arteries (up to 20% vessel wall), and contains longitudinal elastin fibres in the subendothelial CT. Run in a circular orientation around the vessel
IEL present but indistinguidable

14

IEL and EEL of elastic arteries

Internal Elastic lamina: present but indistinguishable from elastic laminae of media (in TI)

External Elastic laminae: between media and adventitia

15

Muscular Arteries: Tunica Intima

1) Endothelium
2) BM of endothelium
3) Subendothelium CT
4) A thick distinctive IEL. Smooth in life but with longitudinal folds after death

16

Muscular Arteries: Tunica Media

Middle and thickest coat.

Smooth muscle fibres control vessel diameter.
Elastic fibres gives resiliency.
Collagen fibres limit expansion to prevent rupture.

**outer margin sometimes includes a EEL, never as prominent as the IEL

17

Muscular Arteries: Tunica Adventitia

Outermost coat. Usually only collagen and elastin fibres. Vasa vasorum to service the outer layers of the vessel wall (these usually only present in larger muscular arteries)

18

Arterial Disease: Atherosclerosis

Narrowing of arteries by plaque filling. Influenced by lifestyle

19

Arterial Disease: Berry Anuerysm

Often found in the brain, upon rupture can lead to a stroke.
Bleeding into the media wall can result

20

Arterial Disease: Dissecting Aneurysm

AAA: Abdominal Aortic Aneurysm
No way to predict
Weakness in wall, usually congenital, can lead to bleeding in the vessel wall
High risk, high % mortality

21

Arterial Disease: Hypertension

Thickening of the vessel wall > high blood pressure

Normal BP: 120/80
Hypertension: >140/90

We see a narrowed lumen, duplication of IEL, thickening of the media (so SM increases) and thickening of the adventitia.

Very thick wall to lumen ratio.

22

Arterioles

Smallest of the muscular arteris
-overall diameter of 100micrometers or less
-3 or less SM layers in media
-Wall thickness = lumen

23

Arterioles: Tunica Intima

endothelial cells overlying a basal lamina. IEL only present in larger arterioles

24

Arterioles: Tunica Media

Thicker muscle coat in the media relative to the lumen then any other vessel. Therefore it is at the arterioles that the biggest pressure drop occurs, as variation in diameter has a huge effect on blood pressure.