LEC 8 Flashcards
Cardiovascular System Part 1
How does blood move through the body? (2)
- A vast, branched network of hollow tubules
- Arteries, Capilleries & Veins
ARTERIES
Thick walled, transports blood AWAY from heart; able to stretch under pressure (distensable)
CAPILLERIES
Microscopic, exchange solutes & water with cells
VEINS
Thin walled, transports blood TOWARDS the heart
Lumen
hollow inside of blood vessels
ARTERIES can ________ due to blood pressure which allows arteries to store blood from each _______
- stretch
- beat
_________ of arteries allows blood flow even between beats
Recoil
ARTERIES structure (inside to outside)
- Endothelium
- Smooth muscle
3.
Endothelium
- innermost layer
- squamous cells to reduce friction
Smooth muscle
- just outside endothelium
- elastic connective tissue for stretching
- thickest layer of the three & can withstand high pressure generated by heart contraction
Connective Tissue
- outermost layer, mostly collagen
- Anchors vessels to surrounding tissue & protects from injury
ANEURYSM
If blood seeps out of endothelium and builds between two outer layers
What can happen during an aneurysm? (4)
- Ballooning of the artery wall
- Can bulge inward completely blocking lumen
- Cause cause pain or be completely asymptomatic
- Rupture!
ARTERIOLES: “Little Arteries”
- Transport & store blood
- Regulate flow of blood between arteries and capillaries with help of precapillary sphincters
Precapillary sphincters act as _______ into individual capillaries
gates
Arterioles have ___ connective tissue since the pressure is ______.
- no
- less
Precapillary sphincters
vasoCONSTRICT or vasoDILATE to regulate amount of blood flowing
Vasoconstrict
Contract
Vasodilate
Relax
