Lecture 6: CIRCULATOR SYSTEM ANATOMY - PART 1 Flashcards
What is the first artery in the pathway from the heart to the foot?
Ascending aorta
What is after the ascending aorta?
Aortic arch
What is after the aortic arch?
Descending aorta
What is after the descending aorta?
Abdominal aorta
What is after the abdominal aorta?
Common iliac artery
What is after the common iliac artery?
External iliac artery
What is after the external iliac artery?
Femoral artery
What is after the femoral artery?
Popliteal artery
What is after the popliteal artery?
Posterior tibial artery
What is after the posterior tibial artery?
Plantar arch
What arteries are in the thoracic cavity?
Ascending aorta, aortic arch and descending artery
What arteries are in the abdominal cavity?
abdominal aorta, common iliac artery and external iliac artery
Where is the popliteal artery sitting?
Posterior to the knee
Where are the supply paths found?
Deep
What is the first vein in the path from the foot to the heart?
Plantar venous arch
What is after the plantar venous arch?
Posterior tibial vein
What is after the posterior tibial vein?
Popliteal vein
What is after the popliteal vein?
Femoral vein
What is after the femoral vein?
External iliac vein
What is after the external iliac vein?
Common iliac vein
What is after the common iliac vein?
Inferior vena cava
Where may drainage paths be found?
Deep and superficial
What vein sits superficially?
Great saphenous vein
Where is the great saphenous vein found?
Running the length of the leg in the hypodermis
What is the longest vein in the body?
The great saphenous vein
Where does the great saphenous vein join the femoral vein?
At the groin
How many layers are in blood vessels?
3
What are the 3 layers of blood vessels?
Tunica intima, tunica media and tunica adventitia
What is the inner layer of blood vessels?
Tunica intima
What is the middle layer of blood vessels?
Tunica media
What is the outer layer of blood vessels?
Tunica adventitia
What are the layers of the tunica intima?
Endothelium, sub-endothelium and internal elastic elamin
What is the endothelium?
A simple squamous epithelium which lines the lumen of all vessels
What does the endothelium act as?
A barrier between blood and the vessel wall which prevents clotting
What is the sub-endothelium?
A sparse pad of loose FCT cushioning and supporting the endothelium
What is the internal elastic lamina?
A condensed sheet of elastic tissue.
How does the IEL compare in veins and arteries?
It is well developed in arteries and less developed in veins
What is the major component of the IEL?
smooth muscle which is under involuntary control and autonomic tone
What is the content of connective tissue in the tunica media?
Variable fibres of mainly elastin and collage
What is the thickness of the tunica media proportional to?
Vessel diameter and blood pressure - thicker in arteries than veins
What is the tunica adventitia composed of?
Loose FCT with a high content of collagen and variable amounts of elastin depending on the vessel
What does the tunica adventitia have in larger vessels?
Vasa vasorum which are blood vessels that supply the blood vessels
What is also found in the tunica adventitia?
Lymphatics and autonomic nerves
What are the two types of arteries?
Elastic arteries and muscular arteries
What do elastic arteries have?
More elastic tissue in the tunica media so that they are able to dampen the high pressure from the heart
What is an example of an elastic artery?
Thoracic artery
What do muscular arteries have?
Less elastin and more smooth muscle cells in the tunica media
What is an example of a muscular artery?
Femoral artery
What are arterioles?
Small arteries which are the last vessel in the supply path before the capillary bed
What is the function of arterioles?
Act as the resistance vessels of the circulation - determine the blood pressure
What is the function of capillaries?
Site of exchange between blood and tissues
What are venules?
The first part of the collecting (drainage) system
What do venules contain?
Monocuspid (one cusp/leaflet) valves to ensure that the blood doesn’t move backwards
What are veins?
A low pressure, large volume transport system
What do veins act to do?
Ensure one way (unidirectional) flow
What type of vessels are veins?
Capacitance vessels which can hold accumulated blood if needed.
Are capillaries capacitance vessels?
no
Are arteries capacitance vessels?
no
What is the structure of veins?
Irregular, flattened shape with large lumen and thin wall
What do veins have?
Spare capacity meaning they can take up extra blood volume
What are the layers of veins?
Intima, media and adventitia
What is the media like in veins?
Much thinner than arteries - a few layers of smooth muscle (often in two distinct layers - circumferential and longitudinal)
What is the adventitia in veins?
Often the thickest layer
Where do deep veins sit?
With skeletal muscle either side of them
What happens to deep veins when the muscle contracts?
It squeezes the vein and therefore pushes the blood up
What stops blood flowing backwards in veins?
Valves
When do varicose veins occur?
when veins dilate and so valve cusps no longer close properly allowing some blood to flow backwards