The systemic circuit Flashcards
1
Q
Where is flow the fastest?
Why is this odd?
A
- Aorta + major arteries
- They have the least total cross-sectional area
2
Q
Where is flow the slowest?
Why is this odd?
A
- Capillaries
- They have the greatest cross-sectional area
3
Q
What 3 layers do all blood vessels have
A
- Tunica adventitia – connective tissue made from collagen fibres
- Tunica media – smooth muscle and elastin
- Tunica intima – endothelium
4
Q
What’s the role of elastic arteries in the arterial system
A
- Large diameter - low resistance pathways
- Lots of elastin to withstand large pressure changes
5
Q
What’s the role of muscular arteries in the arterial system
A
- Deliver blood to specific organs
- Less elastin and more smooth muscle
- Less distensible
6
Q
What’s the role of arterioles in the atrial system
A
- Deliver blood to capillary beds
- Almost entirely smooth muscle
- Diameter regulates blood flow
7
Q
Describe capillaries
A
- Smallest blood vessels
- Form capillary beds
- Blood flow = microcirculation
- Microcirculation is regulated by precapillary sphincters
8
Q
Describe continuous capillaries
A
- Most common type
- Tight junctions between endothelial cells
- Intercellular clefts allow limited passage of fluid + small solutes
9
Q
Describe fenestrated capillaries
A
- Some endothelial cells have fenestrations (oval pores) ∴ more permeable to fluids & small solutes
- Found where active absorption occurs
10
Q
Describe veins in the venous system
A
- Thinner walls + larger lumen than arteries
- Low pressure requires valves to ensure blood flows towards the heart
11
Q
When are venules in the venous system formed
A
Formed when capillaries unite
12
Q
Whats the meaning of systemic blood pressure
A
The pressure exerted on blood vessels in the systemic circulation
13
Q
What is systolic pressure
A
Systolic phase of cardiac cycle
14
Q
What is diastolic pressure
A
Diastolic phase of cardiac cycle
15
Q
How do you solve pulse pressure
A
BPs - BPd
