Blood vessels

Question 1

Describe the structure of blood vessels

Answer 1

• Hollow interior called LUMEN
• Wall consist of 3 layers:
  • Tunica intima (inner layer)
  • Tunica media (middle layer)
  • Tunica externa (outer layer)

Question 2

Tunica intima (inner layer)

Answer 2

Tunica intima: lined by endothelium, smooth texture to reduce friction.

Question 3

Tunica media (middle layer)

Answer 3

Tunica media: composed of smooth muscle and elastic fibres, circular smooth muscle vasodilates and vasoconstricts to change the diameter of the vessels

Question 4

Tunia externa (outer layer)

Answer 4

Tunica externa: a network of collagen fibres to protect and reinforce the vessel and anchor it to surrounding structures.

Question 5

State the differences in structure and function of: Blood vessels

Answer 5

• Arteries - carry blood AWAY from the heart
• Arterioles - carry blood AWAY from the heart
• Capillaries - site of nutrient and gas exchange
• Venules - carry blood TOWARDS the heart
  Veins - carry blood TOWARDS the heart

Question 6

Describe arterial pathway (systemic)

Answer 6

LV pumps blood into ascending aorta -> flows to arteries -> then arterioles -> then capillaries-> to various tissue and organs of the body

Question 7

Describe venous pathway (systemic)

Answer 7

Venous (systemic):
Blood flows out of organ via venules -> venules to veins -> drains to inferior vena cava and superior vena cava -> blood returned to right atrium

Question 8

Identify what is different about pulmonary circulation compared to the systemic circulation in relation to veins and arteries

Answer 8

Pulmonary circulation:
Venules and veins carry oxygenated blood to the heart and arteries and arterioles carry deoxygenated blood to the lungs

Systemic circulation:
Oxygenated blood is carried by arteries and arterioles and deoxygenated blood carried by veins and venules.

Question 9

Identify main blood vessels that are clinically important such as those used for taking vital signs, peripheral circulation checks, JVP and venepuncture

Answer 9

• Femoral vein: may be used to take blood samples or pressure recording from the right side of the heart
• Great saphenous vein: is the longest vein in body. Can be used to replace blocked arteries in the heart for heart bypass operations
• External juglar vein: Used to measure JVP
  Medial cubital, Cephalic and Basilic: veins of choice located in antecubital fossa for blood tests

Question 10

Describe peripheral vascular resistance (PVR)

Answer 10

The opposition to blood flow caused by friction between blood and the vessel wall

Question 11

Describe which blood vessel is the major influence of PVR

Answer 11

Arterioles, peripheral resistance in arterioles helps to determine arterial blood pressure, most resistance is encountered in arterioles and capillaries in peripheries.