Practical 1 - Cardiovascular Flashcards
Describe the flow of blood from artery to veins.
Artery branches into arteriole branches into capillaries merge into venules merge into veins.
What occurs in the capillaries?
Exchange of waste, gas, and nutrients
Describe the difference in appearance of a artery vs vein under the microscope.
Arteries are thicker but have a smaller lumen, and they normally stay completely round. Veins are thinner but have a bigger lumen that is normally collapsed.
What are the effects of vasoconstriction and vasodilation? What causes those two actions to occur?
Vasoconstriction: increase BP, contraction of smooth muscle makes the lumen smaller
Vasodilation: decrease BP, relaxation of the smooth muscle makes the lumen bigger
What is an anastomosis, and what are the three types? Give an example of each type.
It is a vessel that allows for an alternate route of bloodflow.
Arteriovenous anastomosis: between small arteries and veins, like in the fingers (reduce heat loss in the cold weather)
Arterial anastomosis: between arteries, like the Circle of Willis to protect the brain in case of a blockage
Venous anastomosis: between veins, like the deep and superficial veins to regulate temperature
What is a trunk and a portal? Whatisanexampleofaportal?
A trunk is a short vessel that immediately branches.
A portal is a vessel that contains two capillary beds in series (the hepatic portal, where blood goes through the stomach capillaries first but then “stops in” at the liver before being returned).
What are the roles of arterioles?
regulate BP and control flow into the capillaries
What are the differences between elastic and muscular arteries?
Elastic: large diameter, elastic fibers, handle high pressure
Muscular: small diameter, smooth muscle fibers, contract to propel blood
What are all of the layers of an artery? Major layers and sublayers.
Tunic Interna - endothelium, basement membrane, and internal elastic lamina
Tunic media- smooth muscle and external elastic lamina
Tunica externa
What is the role of the tunica media layer of an artery?
Smooth muscle constricts and dilates, while the external elastic lamina helps the artery stretch and return to a normal shape.
What is the tunica externa of an artery made of, and what does it do?
Made of elastic and collagen fibers, supports and protects the artery
What are the layers of a vein? Major and sublayers.
Tunica interna- endothelium and basement membrane
Tunica media- smooth muscle
Tunica externa
What structure is unique to veins (arteries don’t have it)? What are they made from? What is their purpose?
Valves (extension of the tunica interna) that prevent backflow
What layers of the veins and arteries are the thickest? What layers is almost non existent for a venule?
Tunica media is the thickest in an artery, while tunica externa is thickest in a vein (except it can be absent or thin in the venules)
Name differences between arteries and veins regarding the lumen, pressure handled, and thickness.
Arteries have a smaller lumen, but they are thicker and handle more pressure.
Veins have a large lumen but they are thinner and handle less pressure.
What feature is unique to arteries (not in veins)?
Elastic lamina (internal or external)
Name the three types of capillaries, what they allow to pass, and where they may be located.
Continuous: only gasses, located in the blood brain barrier, lungs, CNS, skeletal muscle and connective tissue
Fenestrated: small molecules, located in the kidneys, small intestine, and endocrine glands
Sinusoid: large molecules like proteins, located in the liver, spleen, bone marrow, and pituitary gland
What 5 things acts as “pumps” for blood return?
pressure gradient, respiratory, cardiac suction, muscle, and gravity
What is the meaning of the cardiac suction “pump”?
When chordae tendonae pull the AV valves down it creates just a little suction that draws blood into the atria.
What is the meaning of the pressure gradient “pump”?
There is less pressure in the vena cava than the venules, which favors movement in that direction.
What are the differences in the fetal heart, and what was the purpose of those differences?
Open foramen ovale (before becoming fossa ovalis) and open ductus arteriosus (before becoming ligamentum arteriosum) which allowed blood to bypass the lungs.
What is the purpose of the hepatic portal circulation? What does the hepatic portal vein do?
To filter nutrients from digested food and carry them through the circulation before reaching the heart. The hepatic portal vein carries this nutrient-rich blood to the liver to be filtered and processed.
Explain the process of hepatic portal circulation, starting with blood coming from the affected organs.
Blood from the stomach, pancreas, and spleen drain into the splenic vein. Blood from the large intestine drains into the inferior mesenteric vein. Blood from the small intestine drains into the superior mesenteric vein.
The inferior mesenteric vein merges with the splenic vein. The splenic veins and superior mesenteric vein merge to form the hepatic portal vein.
The hepatic portal vein carries blood to and through the liver, then drains into the hepatic veins.
They merge into the inferior vena cava which takes blood back to the heart.
What arteries supply the Circle of Willis/Cerebral Arterial Circle?
right and left vertebral arteries (enter the circle on the back side) and right and left internal carotid arteries (enter the circle on the sides, toward the middle of the circle)
