Lecture 6 Flashcards
What are arteries?
Supply path, carrying blood under pressure
What are veins?
A low pressure drainage network
What major arteries sit in the thoracic cavity?
Ascending aorta, aortic arch, descending aorta
What is the pathway of the Aorta artery?
From the left side of the heart goes over the arch, down the thoracic aorta, through the abdominal aorta, bifurcates into the left and right common iliac arteries
What structures are located next to the supply aths (arteries?
Deep drainage channels
What occurs after bifurcation in the supply path?
The pathway leads into the left and right common iliac arteries, these arteries have branches including the external iliac artery which leads out to the lower limb and internal that leads to the bowel of the pelvis. We pass through the Inguinal ligament leaving the abdominopelvic cavity and enter the lower limb where the femoral artery begins.
What happens to the artery when it changes cavity?
The name of the artery changes
What artery runs along the back of the knee 9flexor aspect of joint).
Popliteal artery
What artery sits in the posterior region of the leg (amongst the calf muscles?
Posterior tibial artery which leads into the sole of the foot forming connections into the plantar arches.
What is the deep venous pathway of draining blood back to the heart?
Plantar venous arches (foot) - posterior tibial vein (leg) - popliteal vein (knee) - Femoral vein ( lower limb) - external iliac vein (hip) - common iliac vein - inferior vena cava which then drains into the inferior aspect of right atrium.
What is the great saphenous vein?
The longest vein in our body that allows blood to be drained superficially (in the hypodermis) until it joins the deep femoral vein near the groin
What are the layers of a blood vessel wall?
Tunica Intima (innermost) Tunica Media (Middle) Tunica Adventitia (Outer)
What are endothelium?
A simple squamous epithelium which lines the lumen of all blood vessels to create a barrier between the blood and wall.
What are Sub-endothelium?
A sparse pad of lose FCT. cushioning the endothelium. Forms the foundation for the delicate endothelium to rest on.
What are Internal elastic lamina?
Condensed sheet of elastic tissue which forms the boundary between intima and media. Well developed in arteries and less developed in veins.
What structures make up the Tunica Intima?
Endothelium
Sub-endothelium
Internal elastic lamina
What structures make up the Tunica media?
Smooth muscle
A variable content of connective tissue fibres - mainly elastin and collagen
Thickness of the media is proportional to both diameter and blood pressure.
How does the thickness of the media differ between arteries and veins?
An artery is carrying pressurised blood therefore will have a thick media whereas a vein with the blood diameter carries blood of a low pressure therefore will have a thinner media.
What structures make up the Tunica Adventitia?
Lose FCT - high content of collagen and variable amount of elastin
In larger vessels, the adventitia contains vasa vasorum (which requires their own blood supply)
Lymphatic and Autonomic nerves are also found in this region.
How to Vasa Vasorum obtain their own blood supply?
The blood supply enters the mieda and forms capillaries around the smooth muscles in the media by entering in small arteries and draining in small veins through the adventitia.
Where is smooth muscle oriented in blood vessels?
Circumferentially around the vessel so it ha the ability to constrict and dilate, controlling the vessel.
Why do arteries near the heart have a greater elastin content compared to other regions of the body?
Allow a lot of elastic recoil, so they can take up energy during systole when the blood is ejected from the ventricle and then re-exert that energy during diastole when the pressure decreases.
What are arteriols?
The smallest arteries, before they enter into capillaries
What are venules?
Small veins at the first stage of venous drainage
What is pulsatility?
What the heart does to get blood moving out towards the periphery
How is pulsatility dampened (reduced) ?
During systole the wall takes up energy into elastic tissue, then during diastole the rubber recoils passiveky which exerts energy back into lumen, reducing the pulse pressure.
What is the main role of muscular arteries?
Directing blood flow to skeletal muscle to meet their metabolic demands. It does this by Changing the time of the smooth muscle in the media and change the size of the lumen of that artery, redistributing which vessels are carrying more or less ood in order to distribute blood to the appropriate targets.
which cells in the blood vessel contain the nuclei?
Endothelium
Structure of arterioles?
Same as arteries but on a smaller scale
Function of arterioles?
The resistance vessels of the circulation - determine blood pressure
Where are mono cuspid valves located?
In venules to prevent blood from flowing backwards
Function of veins?
Low pressure, large volume transport system
Unidirectional flow
Capacitance vessels (have spare capacity to take up extra blood volume)
Structure of veins?
Flattened and irregular shape with large lumen and thin wall. They also have three layers; Intima, media and adventitia
How is the media in a vein structurally different ton that of an artery?
The media of a vein is much thinner as it consist of only a few layers of smooth muscle (often in two distinct layer)
How is the adventitia of a vein structurally different ti that of an artery?
The adventitia of a vein is one of the thickest layers of the vein wall as it is the collagen thick layer and it’s ability to act as a capacitance vessel.
What is a vascular bundle?
Deep bundle running the the posterior compartment of the leg. Consists of an artery flanked by two veins.
How can you tell if a vein is deep or superficial?
A deep vein will be flanked by skeletal muscle
What causes varicose valves?
failure of valves to undergo unidirectional flow which causes the veins to dilate
