Unit 7: Cardiovascular System

Interstitial fluid

The fluid between blood vessels and cells, consisting of water, nutrients, hormones, enzymes, and waste products.

Blood vessels

Structures that carry blood throughout the body, requiring resilience and flexibility.

Anastomosis

The joining of two vessels, allowing a connection between peripheral vessels without involving a capillary bed.

Collateral

More than one artery supplying the same area, serving as backup vessels.

Angiogenesis

The formation of new blood vessels, controlled by vascular endothelial growth factor (VEGF).

Artery

Blood vessels that carry blood away from the heart, characterized by high pressure and numerous elastin fibers.

Arteriole

A small arterial branch that delivers blood to capillary networks.

Capillary

The smallest blood vessels, facilitating the diffusion of gases, nutrients, and waste between blood and interstitial fluid.

Venule

A small vein that receives blood from capillaries and unites to form larger veins.

Vein

A blood vessel carrying blood from capillary beds toward the heart, containing valves to prevent backflow.

Tunica intima

The innermost layer of blood vessel walls, made of simple squamous epithelium and a thin layer of connective tissue.

Tunica media

The middle layer of blood vessels, composed of elastic fibers and smooth muscle, responsible for vasoconstriction and vasodilation.

Tunica externa

The outermost layer of blood vessels, made of connective tissue that anchors the vessel to surrounding tissues.

Elastic arteries

Large arteries that transport blood away from the heart, rich in elastic fibers.

Muscular arteries

Medium-sized arteries with thicker tunica media that allow vasoconstriction and vasodilation.

Vasodilation

An increase in the diameter of arterioles due to relaxation of smooth muscle in the tunica media.

Vasoconstriction

A reduction in the diameter of arterioles due to the contraction of smooth muscles in the tunica media.

Capillary bed

An interconnected network of capillaries where diffusion and exchange occur.

Precapillary sphincter

A band of smooth muscle that regulates blood flow into capillary beds.

Capillary exchange

The process of exchanging gases and nutrients between blood and interstitial fluid at the capillary level.

Filtration

The process by which hydrostatic pressure pushes solutes and solvents from the capillaries into the interstitial fluid.

Reabsorption

The process of drawing fluid back into the capillaries, mainly through osmosis.

Medium-sized veins

Veins with a thin tunica media and thicker adventitia, transporting blood back to the heart.

Large veins

Veins, such as the superior and inferior vena cava, with all three layers thickest in large veins.

Venous valves

Structures within veins that prevent backflow of blood in a low-pressure system.

Pulse pressure

The difference between systolic and diastolic blood pressure, indicating the strength of the pulse wave.

Mean arterial pressure (MAP)

The average arterial pressure during one cardiac cycle, indicative of perfusion.

Total peripheral resistance

Resistance to blood flow through small vessels, determined by factors like vessel diameter and blood viscosity.

Autoregulation

Immediate, localized homeostatic adjustments in blood flow, often involving vasodilation and vasoconstriction.

Baroreceptors

Sensors located in blood vessels that monitor blood pressure and stretch, adjusting blood flow accordingly.

Chemoreceptors

Sensory receptors that monitor chemical composition and pH of the blood, influencing cardiovascular responses.

Antidiuretic hormone (ADH)

A hormone released in response to low blood pressure, promoting water retention to elevate blood pressure.

Aldosterone

A hormone that stimulates sodium conservation and thus helps to elevate blood pressure.

Erythropoietin (EPO)

A hormone that stimulates red blood cell production in response to low oxygen or blood pressure.

Natriuretic peptides

Hormones released in response to excessive cardiac stretch, promoting sodium and water loss to lower blood pressure.

Hypertension

High blood pressure, typically above 140/90 mmHg, with two types: primary and secondary hypertension.

Hypotension

Low blood pressure, typically below 100/60 mmHg, which can result in insufficient blood flow.

Edema

An abnormal increase in interstitial fluid due to excess filtration that exceeds reabsorption.

Foramen ovale

A flap-like opening in the interatrial septum during fetal circulation that allows blood to bypass the lungs.

Ductus arteriosus

A fetal blood vessel that allows blood from the pulmonary trunk to bypass the lungs.

Fetal circulation

The circulation pattern in fetuses that allows oxygenated blood from the placenta, bypassing the lungs.

Systemic circuit

The part of the cardiovascular system that carries oxygenated blood from the heart to the body.

Pulmonary circuit

The part of the circulatory system that transports deoxygenated blood from the heart to the lungs.

Aortic arch branches

The three main arteries branching from the aortic arch supply the head, neck, and arms.

Aging effects on cardiovascular system

Changes such as reduced elasticity of blood vessels, decreased cardiac output, and increased risk of clots.

Vascular endothelial growth factor (VEGF)

A protein that stimulates angiogenesis and the formation of new blood vessels.