Blood, Cardiovascular System, and Circulation Study Guide

Vocabulary flashcards covering the key terms and concepts from human anatomy and physiology chapters on blood, heart structure/function, and systemic circulation.

Formed Elements

The cellular components of blood suspended in plasma, consisting of red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).

Plasma

The non-cellular liquid portion of blood, consisting of approximately $90\%$ water along with dissolved solutes such as proteins, nutrients, gases, and wastes.

Albumin

The most abundant solute and plasma protein produced by the liver, which functions as a transport carrier, blood buffer, and osmotic contributor.

Erythrocytes

Biconcave, anucleate blood cells filled with hemoglobin whose primary function is the transport of respiratory gases.

Oxyhemoglobin

The bright red compound formed when oxygen reversibly binds to the iron-containing heme group of hemoglobin.

Deoxyhemoglobin

The reduced form of hemoglobin that remains after bound oxygen is released to tissues.

Carbaminohemoglobin

The complex formed when carbon dioxide binds to the amino acids of hemoglobin, accounting for approximately $20\%$ of $CO_2$ transport.

Hematopoiesis

The general process of blood cell formation occurring in red bone marrow, originating from the universal stem cell hemocytoblast.

Erythropoiesis

The specific developmental process of red blood cell production, regulated by the hormone erythropoietin.

Erythropoietin (EPO)

A hormone produced primarily by the kidneys that directly stimulates erythropoiesis in response to hypoxia.

Hypoxia

A condition of inadequate oxygen delivery to body tissues, which triggers the release of erythropoietin.

Anemia

A condition characterized by an abnormally low oxygen-carrying capacity of the blood, resulting from blood loss, low RBC production, or high rate of RBC destruction.

Polycythemia

An abnormal excess of erythrocytes that increases blood viscosity, hindering flow.

Diapedesis

The active passage of white blood cells through unbroken capillary walls into surrounding tissue spaces.

Leukopenia

An abnormally low total white blood cell count.

Leukocytosis

An elevated total white blood cell count, typically serving as a normal physiological reaction to infection.

Granulocytes

A category of leukocytes containing cytoplasmic granules, comprising neutrophils, eosinophils, and basophils.

Agranulocytes

A category of leukocytes lacking visible cytoplasmic granules, comprising lymphocytes and monocytes.

Leukopoiesis

The production and development of white blood cells, regulated by chemical messengers such as interleukins and colony-stimulating factors.

Leukemia

A group of cancerous conditions marked by uncontrolled overproduction of abnormal, nonfunctional white blood cells.

Platelets (Thrombocytes)

Anucleate cell fragments pinched off from megakaryocytes that function in blood clotting.

Thrombopoietin

The hormone that regulates the production of megakaryocytes and platelets.

Hemostasis

A fast, localized response that stops bleeding, consisting of vascular spasm, platelet plug formation, and blood coagulation.

Coagulation

The complex process of blood clotting involving prothrombin activator formation, prothrombin conversion to thrombin, and insoluble fibrin mesh formation.

Fibrinolysis

The enzymatic breakdown of a clot meshwork following tissue repair.

Plasmin

The active fibrin-digesting enzyme responsible for clot dissolution during fibrinolysis.

Thrombus

A persistent clot that forms and remains attached within an unbroken blood vessel.

Embolus

A thrombus or clot fragment that breaks free from a vessel wall and travels through the bloodstream.

Thrombocytopenia

A bleeding disorder characterized by a deficient number of circulating platelets, leading to petechiae and delayed clotting.

Antigens (Agglutinogens)

Glycoproteins on the surface of erythrocytes that distinguish cell identity and determine blood type.

Antibodies (Agglutinins)

Preformed plasma proteins that bind specifically to foreign erythrocyte surface antigens.

Mediastinum

The medial thoracic cavity compartment containing the heart, surrounded by the lungs.

Epicardium

The visceral layer of the serous pericardium, forming the outer layer of the heart wall.

Myocardium

The middle layer of the heart wall composed of contractile cardiac muscle cells.

Endocardium

The inner endothelial lining of the heart chambers and covering of heart valves.

Tricuspid Valve

The right atrioventricular (AV) valve preventing backflow of blood into the right atrium during ventricular contraction.

Bicuspid (Mitral) Valve

The left atrioventricular (AV) valve preventing backflow of blood into the left atrium during ventricular contraction.

Chordae Tendineae

Collagenous cords anchoring AV valve cusps to papillary muscles, preventing valve flap eversion.

Papillary Muscles

Ventricular muscular projections that contract to exert tension on the chordae tendineae.

Coronary Circulation

The functional blood supply system that delivers blood directly to and from the myocardium.

Sinoatrial (SA) Node

The primary pacemaker of the heart located in the right atrial wall that sets the intrinsic sinus rhythm.

Atrioventricular (AV) Node

A node in the inferior interatrial septum that delays impulse transmission by about $0.1\,s$ to allow atrial contraction before ventricular excitation.

Bundle of His (AV Bundle)

The sole electrical conduit transmitting impulses between the atria and ventricles.

Purkinje Fibers

Conduction pathways that extend through the apex and ventricular walls to directly stimulate cardiac muscle cells.

Heart Block

An intrinsic conduction failure where impulses fail to propagate from the AV node to the ventricles.

P Wave

The wave on an electrocardiogram (ECG) corresponding to atrial depolarization.

QRS Complex

The wave pattern on an electrocardiogram (ECG) corresponding to ventricular depolarization.

T Wave

The wave on an electrocardiogram (ECG) corresponding to ventricular repolarization.

Systole

The period of heart muscle contraction during which blood is ejected from a chamber.

Diastole

The period of heart muscle relaxation during which heart chambers fill with blood.

Cardiac Output (CO)

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

Stroke Volume (SV)

The volume of blood pumped out by a ventricle with each heart beat, calculated as $\text{SV} = \text{EDV} - \text{ESV}$.

Preload

The degree of stretch of cardiac muscle cells prior to contraction, influencing End Diastolic Volume (EDV).

Contractility

The intrinsic contractile force of heart muscle at a given length, influencing End Systolic Volume (ESV).

Afterload

The arterial backpressure that ventricles must overcome to eject blood into circulation.

Tachycardia

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

Bradycardia

An abnormally low resting heart rate less than $60\,\text{beats per minute}$.

Angina Pectoris

Thoracic chest pain caused by temporary ischemia to myocardium without permanent cell necrosis.

Myocardial Infarction

A heart attack resulting from prolonged coronary vascular obstruction leading to tissue ischemia and cell death.

Tunica Intima

The innermost lining layer of blood vessels, containing endothelium and a thin basement membrane.

Tunica Media

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

Tunica Externa

The outer protective layer of blood vessels made of woven collagen fibers.

Elastic Arteries

Thick-walled conducting arteries near the heart that contain elastin in all tunics to accommodate pressure surges.

Muscular Arteries

Distributing blood vessels with a thick tunica media rich in smooth muscle, active in vasoconstriction.

Arterioles

The smallest arterial branches leading directly to capillary beds, serving as resistance vessels.

Continuous Capillaries

The most common and least permeable capillary type, possessing uninterrupted endothelial walls joined by tight junctions.

Fenestrated Capillaries

Capillaries containing explicit pores that facilitate high permeability for absorption and filtration.

Sinusoidal Capillaries

Leaky, wide capillaries with large clefts and fenestrations allowing passage of whole cells and large proteins.

Precapillary Sphincter

A smooth muscle valve surrounding the root of a true capillary that regulates blood flow into capillary beds.

Capacitance Vessels

A functional designation for veins because of their thin walls, large lumens, and ability to store blood.

Systolic Pressure

Peak blood pressure produced in arterial walls during ventricular systole, normally averaging $120\,\text{mmHg}$.

Diastolic Pressure

Lowest arterial blood pressure recorded during ventricular diastole, normally averaging $80\,\text{mmHg}$.

Pulse Pressure

The arterial pressure difference calculated as $\text{Pulse Pressure} = \text{Systolic Pressure} - \text{Diastolic Pressure}$.

Mean Arterial Pressure (MAP)

The calculated average pressure driving blood flow to tissues, given by $\text{MAP} = \text{Diastolic Pressure} + \frac{1}{3}(\text{Pulse Pressure})$.

Baroreceptors

Sensory nerve endings in carotid sinuses and the aortic arch sensitive to arterial stretch and pressure changes.

Tissue Perfusion

Blood flow through body tissues delivering oxygen and nutrients while clearing metabolic wastes.

Autoregulation

The intrinsic local process by which an organ alters its blood flow to meet specific metabolic needs.

Nitric Oxide (NO)

A potent endothelial vasodilator chemical that causes relaxation of vascular smooth muscle.

Hypertension

A chronic medical condition defined as sustained resting arterial blood pressure of $140/90\,\text{mmHg}$ or higher.

Hypotension

A low blood pressure condition defined as systolic arterial pressure below $90\,\text{mmHg}$.

Circulatory Shock

A state in which blood vessels are inadequately filled and blood flow is insufficient to meet tissue needs.

Hypovolemic Shock

A severe form of circulatory shock caused by acute, large-scale loss of blood or bodily fluid.

Vascular Shock

Circulatory shock caused by extreme, widespread vasodilation causing inadequate tissue perfusion despite normal blood volume.

Cardiogenic Shock

Circulatory shock resulting from myocardial failure where the heart pump is inefficient to maintain circulation.