Blood Vessel Flashcards
What are the types of Blood vessels?
- Arteries and arterioles
- Capillaries
- Veins and Venules
Blood vessel walls consist of 3 layers. What are the three layers called?
- Tunica initima
- Tunica media
- Tunica externa
Describe the tunica intima?
- Inner layer
- Lined by endothelium
- It has a smooth texture to reduce friction
Describe the tunica media?
- Composed of smooth muscle and elastic fibres
- Circular smooth muscles vasodilates and vasoconstricts to change the diameter of the vessels
Describe the tunica externa?
- It has a network of collagen fibres to protect and reinforce the vessels and anchor it to surrounding structures
- It has nerve fibres and elastic fibres in larger vessels
Describe muscular arteries?
- They carry blood to the furthest destination from the heart
- They have a thicker wall made from smooth muscles
Describe elastic Arteries?
- Nearest to the heart
- They have a larger lumen= low resistance to blood flow
- They can stretch and recoil without causing damage to accommodate for high pressure
Describe arterioles
- They deliver blood to capillaries
- They are the major influencer of peripheral resistance
Describe capillaries
- They carry blood from arterioles to venules
- They have very thin walls so they are ideal for diffusion
- They are microscopic vessels
Describe Venules
- Capillaries unite to form venules
- They transport blood to veins
- Walls consist of endothelial cells and a few smooth muscles
Describe Veins
- They act as blood reservoirs which can be drawn on when BP drops
- Contain one way valves
- Contraction of skeletal muscles assists in the flow of blood in veins
What is the arterial pathway-systemic?
- LV pumps blood into ascending aorta
- Flows to arteries
- Then arterioles
- Then capillaries
- To various tissues and organs of the body
What is the venous pathway-systemic
- Blood flows out of organ via venules
- Venules to veins
- Brain to inferior vena cava and superior vena cava
- Blood return to right ventricle
During pulmonary circulation do veins and venules carry oxygenated or deoxygenated blood to the heart?
Oxygenated
During pulmonary circulation do arteries and arterioles carry oxygenated or deoxygenated blood to the lungs?
Deoxygenated
During systemic circulation do arteries and arterioles carry oxygenated or deoxygenated blood?
Oxygenated
During systemic circulation do veins and venules carry oxygenated or deoxygenated blood?
Deoxygenated
Describe peripheral vascular resistance (PVR)
The opposition to blood flow caused by friction between blood and the vessel wall
Where is the most PVR encountered?
Most resistance is encountered in arterioles & capillaries in the peripheries
Why is peripheral resistance in arterioles important?
It helps to determine arterial blood pressure
What are the three arteries that branches off the aortic arch to supply the neck, upper limbs and part of the thorax wall?
- Brachiocephalic
- Left comman carotid
- Left subclavian
What are the arteries that supply the upper limbs?
- Brachial artery
- Radial arterial
- Ulna artery
List the carotid arteries
- External carotid
- Internal carotid
- Temporal artery
What does the External carotid supply?
Supplies tissues of head
