Lecture 11 - Circulatory System

Flashcards for lecture 11 on the circulatory system, focusing on the vascular part, the blood vessel part.

Arteries

Carry blood away from the heart.

Veins

Carry blood towards the heart.

Capillaries

The smallest blood vessels, where exchange between the blood and tissue fluid occurs.

Lumen

The space within a hollow structure or organ, particularly tubular structures.

Tunica Interna

The most internal layer of blood vessels, also called Tunica Intima, composed of an endothelial layer.

Tunica Media

The middle layer of blood vessels, containing smooth muscle and elastic fiber, regulated by the sympathetic nervous system to control vasoconstriction and vasodilation.

Tunica Externa

The outer layer of blood vessels, containing collagen fibers that protect and reinforce the vessels, also called tunica adventitia.

Vasoconstriction

Narrowing of blood vessels.

Vasodilation

Widening of blood vessels.

Elastic Arteries

The largest arteries, also called conducting arteries, with the greatest diameter and little resistance to blood flow.

Muscular Arteries

Arteries that help deliver blood to the body's organs, with a thick tunica media and involved with vasoconstriction, also called distributing arteries.

Arterioles

The smallest part of the arterial system, important for regulating blood flow into capillary beds through vasodilation and constriction.

Capillaries

Walls of thin tunica interna, only one cell thick, and a very narrow diameter that allows only a single red blood cell to pass.

Paracellular Transport

Passageway of molecules that are going between adjacent epithelial cells.

Continuous Capillaries

Capillaries with a complete and continuous lining connected by tight junctions, found in places like the skin, lungs, and muscles.

Fenestrated Capillaries

Capillaries with pores or fenestrations that allow for small molecules to pass, associated with the intestines, endocrine system, and kidneys.

Sinusoidal Capillaries

The leakiest capillaries, with few tight junctions, allowing larger molecules such as blood cells to pass through, mostly found in the spleen and bone marrow.

Precapillary Sphincters

Regulate blood flow through capillary beds, helping to regulate whether blood is flowing into true capillaries or not.

Venules

Formed from united capillary beds; come together to form veins.

Veins

Act as blood reservoirs, containing approximately 60% of the blood supply at rest.

Valves

Structures in veins that help prevent backflow due to low blood pressure.

Systole

Contraction of a heart chamber.

Diastole

Relaxation of a heart chamber.

Aorta

Major blood vessel with extremely high pressure closest to the heart where blood pressure is highest.

Systemic Circulation

System consisting of blood vessels that extend to and from the heart.

Aorta and Vena Cavae

The great vessels.

Circle of Willis

Enables alternative channels for blood to travel to supply the brain, important for equalizing blood pressure in the brain.

Vertebral Artery

Subclavian artery branch which supplies blood to posterior brain.

Thyrocervical Trunk

Subclavian artery branch which supplies blood to the scapular muscles and the thyroid gland.

Costocervical Trunk

Subclavian artery branch which supplies blood to the deep muscles of the neck.

Axillary Artery

Located in the armpit.

Brachial Artery

Located along the humerus before it splits into the radius and ulna.

Radial Artery

Supplies blood to the radial side of the forearm

Ulnar Artery

Supplies blood to the ulnar side of the forearm

Bronchial Arteries

Arteries that supply blood to the lungs.

Left Gastric Artery

Supplies blood to the stomach.

Splenic Artery

Supplies blood to the spleen.

Common Hepatic Artery

Supplies blood to the liver, gallbladder, duodenum, and head of the pancreas.

Femoral Artery

Artery that supplies blood to the thigh.

Venous Plexuses

Unusual drainage patterns such as the dural sinuses in the brain and hepatic portal system.

Brain Veins

Drain into intracranial dural sinuses

Median Cubital Vein

Location where blood is usually drawn.

Great Saphenous Vein

Longest vein in the human body; empties into the femoral vein.

Small Saphenous Vein

Empties into the popliteal vein.