week 7+8 - circulatory system and anatomy of blood vessels Flashcards
the cardiovascular system has 2 main parts:
circulatory
o Blood vessels
o Main transport = BLOOD
the cardiovascular system has 2 main parts:
- circulatory
- lymphatic
the cardiovascular system has 2 main parts:
lymphatic
o Lymph nodes and vessels
o Main transport = LYMPH (colourless body fluid)
the circulatory system has 5 main functions
- Carry blood
- Exchange
- Transport
o Hormones, immune cells, coagulation molecules, enzymes, nutrients, gases, waste - Regulate blood pressure
o Circulatory system works well with heart to maintain blood pressure within a normal range - Direct blood flow to tissue
o Maintain homeostasis
circulatory system
- right atrium (deoxygenated blood)
–(tricuspid valve)–> - right ventricle
–(pulmonary valve)–> - pulmonary trunk and pulmonary arteries
- in pulmonary capillaries blood loses CO2 and gain O2
- pulmonary veins, oxygenated blood
- left atrium
—(bicupsid valve)–> - left ventricle
–(aortic valve)–> - aorta and systemic arteries
- in systemic capillaries blood loses O2 and gains CO2
- superior vena cava, inferior vena cava, coronary sinus
—–> all lead back to 1
summary of human circulatory system
- Heart pushes blood along vessels
- Double circulatory system: blood passes through heart x2
o once – oxygen from lungs
o 2nd – pushed around body
blood distribution
- At rest, the largest portion of the blood is in systemic veins and venules (blood reservoirs)
Reservoirs because it can be directed quickly to where it is needed
64% - systemic veins and venules (blood reservoirs)
9% - pulmonary vessels
7% - heart
13% - systemic arteries and arterioles
7% - systemic capillaries
BASIC STRUCTURES OF VESSELS
in general 3 layers:
- tunica interna
- tunica media
- tunica externa
BASIC STRUCTURES OF VESSELS
in general 3 layers:
1. Tunica interna (or tunica intima)
- Innermost layer, adjacent to lumen
- Thinnest layer of the three and the endothelium is continuous from the lining of the heart
- Really smooth to reduce the amount of friction
- Plays a role in influencing the blood flow
- The basement membrane provides support for the endothelial layer
BASIC STRUCTURES OF VESSELS
in general 3 layers:
2. Tunica media
- Middle layer, smooth muscle and elastic fibres
- Muscular and connective tissue layer
- This is the layer that changes the most, highest variability
- In smooth muscle found in rings around the diameter
o This helps squeeze the blood vessel in order to allow the blood to flow
BASIC STRUCTURES OF VESSELS
in general 3 layers:
3. Tunica externa
- Outermost layer, adjacent to surrounding tissue
- Elastin and collagen fibres
- Also nerves in this layer which help to anchor the vessel to the surrounding tissue as well
ARTERIES AND ARTERIOLES
Carry blood AWAY from the heart.
Elastic walls absorb impact from ventricles.
Thick walls
ELASTIC ARTERY VS. MUSCULAR ARTERY
diameter
elastic: large
muscular: medium
elastic fibres: smooth muscles
elastic: more elastic
muscular: more smooth muscle
functions
elastic: blood heart to muscular arteries
muscular: distribute blood
Well defined elastic laminar
It stretches and can temporarily over stretch and recoil to help push blood along
Smooth muscular layer which makes up about 3/4 of the mass
* Great capacity for viso constriction and viso dilatation of the blood vessels
ARTERIOLES
- Thin tunica interna
- Fenestrated (small pores) and thin internal elastic lamina
- Tunica media: 2 layers of smooth muscle cells in circular orientation
- Terminal end: metarteriole
- Metarteriole-capillary junction: precapillary sphincter
- Regulate blood flow into capillaries
CAPILLARIES
- Smallest blood vessel
- Exchange vessels (large surface area, thin walls)
- Tunica interna only (endothelial cells and basement membrane
How many capillaries in tissues dependent on what metabolic needs the tissues have
