A&P Study Guide: Blood, Heart, and Circulation

Erythrocytes (RBCs)

Transport oxygen via hemoglobin; no nucleus; biconcave for gas exchange.

Leukocytes (WBCs)

Immune defense; five types (neutrophils, eosinophils, basophils, lymphocytes, monocytes).

Platelets

Cell fragments involved in clotting (thrombocytes).

Hematopoiesis

Occurs in red bone marrow from hematopoietic stem cells.

Erythropoiesis

Regulated by erythropoietin.

Leukopoiesis

Depends on cytokines.

Thrombopoiesis

Driven by thrombopoietin.

Anemia

RBC disorder.

Polycythemia

RBC disorder.

Leukemia

WBC disorder.

Leukopenia

WBC disorder.

Thrombocytopenia

Low platelets.

Hemophilia

Clotting disorder.

Heart Location

Mediastinum; apex points left.

Heart Coverings

Fibrous and serous pericardium (parietal + visceral/epicardium).

Epicardium

Outer layer of the heart.

Myocardium

Cardiac muscle.

Endocardium

Inner lining of the heart.

Pulmonary Circuit

Right heart = pulmonary (to lungs).

Systemic Circuit

Left heart = systemic (to body).

AV Valves

Tricuspid (R), Mitral (L) — anchored by chordae tendineae.

Semilunar Valves

Aortic and Pulmonary — prevent backflow from arteries.

Cardiac Output (CO)

CO = HR × SV.

Stroke Volume (SV)

SV = EDV - ESV.

Heart Rate (HR) Control

Controlled by ANS: Sympathetic = ↑HR, Parasympathetic = ↓HR.

Vessel Structure

3 Layers: Intima (endothelium), Media (smooth muscle — vasoconstriction/dilation), Externa (connective tissue).

Blood Flow Equation

Flow = Pressure ÷ Resistance.

Mean Arterial Pressure (MAP)

MAP = DBP + 1/3(PP).

Hypertension

High BP.

Hypotension

Low BP.

Shock

Inadequate circulation (hypovolemic, vascular, cardiogenic).

Capillary Exchange

Diffusion & bulk flow; Hydrostatic vs osmotic pressure.

Pulmonary Circuit

Heart → lungs → heart.

Systemic Circuit

Heart → body → heart.

Fetal Circulation

Foramen ovale, ductus arteriosus, ductus venosus.

Types of WBCs

Never Let Monkeys Eat Bananas: Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils

Steps of Hemostasis

Vascular People Create Clots: Vasoconstriction, Platelet plug formation, Coagulation, Clot retraction & repair

Pathway of Blood Through the Heart

To Right Places Lungs Left Body: To body → Right atrium, right ventricle, pulmonary circulation, left atrium, left ventricle, systemic circulation

Heart Valve Order

Try Pulling My Aorta: Tricuspid (right AV), Pulmonary (right SL), Mitral (left AV), Aortic (left SL)

Conduction System Pathway

Some Angry Bats Bite People: SA node, AV node, Bundle of His, Bundle branches, Purkinje fibers

Layers of Blood Vessel Walls

Tuna Is My Ex: Tunica Intima, Tunica Media, Tunica Externa

Factors Affecting Resistance

VLD: Viscosity, Length of vessel, Diameter (most influential)

Regulators of BP (Short-Term)

CAN Bee Cool: Chemoreceptors, ANS, Neural centers, Baroreceptors, Cortex/Hypothalamus

Capillary Exchange

High Pressure Out, Osmotic Pulls In: Hydrostatic pressure pushes out, Osmotic pressure pulls in