Cardiovascular System and Blood Lecture Review

Vocabulary practice flashcards covering blood components, heart anatomy, cardiac electrophysiology, cycle dynamics, and blood vessel physiology.

Plasma

The liquid portion of unclotted blood that makes up about $55\%$ of total blood volume, consisting of about $91-92\%$ water, $7-8\%$ proteins, and $1\%$ nutrients, hormones, electrolytes, and wastes.

Serum

The fluid portion of blood remaining after clotting has occurred.

Albumin

The major plasma protein responsible for maintaining plasma osmotic pressure and buffering blood pH within the range of $7.35-7.45$.

Fibrinogen

A plasma protein essential for blood clotting that is converted into insoluble fibrin to form a clot.

Erythrocytes

Red blood cells (RBCs); small, flexible, biconcave cells lacking a nucleus and most organelles, containing hemoglobin to transport oxygen, and having a lifespan of about $120\,\text{days}$.

Spectrin

A structural protein in red blood cells that allows them to change shape and form stacked structures called rouleaux.

Erythropoiesis

The process of red blood cell production, controlled by erythropoietin, testosterone, cytokines, iron, vitamin B12, folic acid, and protein.

Leukocytes

White blood cells (WBCs); nucleated cells containing organelles that serve as the body's secondary defense against infection.

Chemotaxis

The movement of white blood cells toward chemical signals or foreign proteins.

Diapedesis

The process by which white blood cells pass through capillary walls into surrounding tissues.

Neutrophils

The most abundant granulocytes ($40-70\%$ of WBCs), acting as the primary defense against short-term infections and phagocytosing bacteria.

Basophils

Granulocytes comprising less than $1\%$ of WBCs that release histamine to cause vasodilation and heparin to prevent clotting during inflammatory or allergic responses.

Monocytes

The largest white blood cells ($2-8\%$ of WBCs) that enter tissues to differentiate into functional macrophages.

Hemostasis

The three-phase process that stops bleeding, consisting of vascular spasms/vasoconstriction, platelet plug formation, and blood coagulation.

Thrombus

A blood clot attached to the wall of a blood vessel.

Embolus

A free-floating clot moving through the bloodstream.

Pericardium

A double-walled sac that encloses the heart, consisting of an outer fibrous pericardium and an inner serous pericardium.

Cardiac Tamponade

A condition in which excess fluid accumulates in the pericardial space, compressing the heart and restricting its ability to pump.

Myocardium

The middle contractile layer of the heart wall composed of branched cardiocytes reinforced by a fibrous skeleton of collagen and elastin.

Endocardium

The inner endothelial layer of the heart wall that lines heart chambers, covers heart valves, and prevents blood sticking.

Pulmonary Circuit

The blood pathway that carries deoxygenated blood from the right ventricle to the lungs and returns oxygenated blood to the left atrium.

Systemic Circuit

The blood pathway that carries oxygenated blood from the left ventricle to body tissues and returns deoxygenated blood to the right atrium.

Chordae Tendinae

Collagen cords that attach atrioventricular valve flaps to papillary muscles, preventing valve inversion into the atria during ventricular contraction.

Intercalated Discs

Intermeshed plasma membrane regions between adjacent cardiac cells containing desmosomes for structural attachment and gap junctions for electrical propagation.

Sinoatrial Node (SA Node)

The pacemaker of the heart located in the right atrial wall, normally depolarizing $70-80\,\text{times per minute}$ to initiate atrial contraction.

Atrioventricular Node (AV Node)

A conducting tissue structure located in the interatrial septum that delays the SA node impulse so the atria can finish contracting before relaying the signal to the ventricles.

P Wave

The initial small wave on an ECG tracing representing atrial depolarization caused by the electrical impulse from the SA node.

QRS Complex

The second and larger wave sequence on an ECG tracing representing ventricular depolarization.

T Wave

The wave on an ECG tracing representing ventricular repolarization.

Cardiac Output (CO)

The volume of blood pumped out of each ventricle in one minute, calculated as $\text{CO} = \text{HR} \times \text{SV}$.

Stroke Volume (SV)

The volume of blood ejected by a ventricle during one contraction, calculated as $\text{SV} = \text{EDV} - \text{ESV}$.

Preload

The degree of stretch on cardiac muscle fibers before contraction, directly related to end-diastolic volume (EDV).

Afterload

The pressure that must be overcome before ventricular contraction can begin to open semilunar valves and eject blood.

Tachycardia

A resting heart rate greater than $100\,\text{beats per minute}$.

Bradycardia

A resting heart rate below $60\,\text{beats per minute}$.

Tunica Intima

The innermost vessel layer facing the lumen, composed of endothelium resting on a connective tissue basement membrane.

Tunica Media

The middle layer of a blood vessel wall, containing elastic tissue and smooth muscle that regulates vessel diameter.

Tunica Externa

The outermost layer of a blood vessel wall made of collagen fibers that protect and anchor the vessel; also called the adventitia.

Vasa Vasorum

Tiny blood vessels that supply nutrient-rich blood to the exterior tissues of large blood vessels.

Elastic Arteries

Large, thick-walled conducting arteries near the heart (such as the aorta) that contain elastic lamina to withstand pressure changes and recoil during diastole.

Muscular Arteries

Distributing blood vessels containing abundant smooth muscle in their tunica media that deliver blood to specific organs.

Arteriosclerosis

A disease state marked by thickening and hardening of arterial walls, leading to loss of recoil and higher arterial pressure.

Atherosclerosis

A form of arteriosclerosis caused by endothelial damage, resulting in lipid plaque formation between the tunica intima and tunica media.

Continuous Capillaries

The most common capillaries, featuring an unbroken endothelial membrane with intercellular clefts for fluid and nutrient exchange.

Fenestrated Capillaries

Capillaries containing oval pores (fenestrations) in their walls to allow high permeability at active absorption sites.

Sinusoids

Highly modified, leaky capillaries with irregular lumens found in organs like the liver, bone marrow, and spleen, allowing blood cells and proteins to pass.

Pulse Pressure

The calculated numeric difference between systolic pressure and diastolic pressure.

Mean Arterial Pressure (MAP)

The average arterial pressure propelling blood to tissues throughout the cardiac cycle, calculated as $\text{MAP} = \text{Diastolic Pressure} + \frac{\text{Pulse Pressure}}{3}$.

Circulatory Shock

A severe clinical state resulting from inadequate perfusion of blood vessels, leading to impaired circulation, cellular death, and organ damage.