Cardiovascular System & Blood – Exam Review

46 flashcards covering heart anatomy, coronary & fetal circulation, intrinsic conduction, hemodynamics, vessel structure, blood components, and key physiology for cardiovascular exam review.

What are the four layers of the heart (outermost to innermost)?

Pericardium, Epicardium, Myocardium, Endocardium

Which heart layer is responsible for contraction?

Myocardium

What is the function of the pericardial cavity surrounding the heart?

Creates a friction-reduced environment for the beating heart.

Which vessel collects most venous blood from the myocardium and empties into the right atrium?

Coronary sinus

What is the 'widow-maker' artery and why is it dangerous?

The left anterior descending (LAD) coronary artery; blockage leads to large anterior wall myocardial infarction.

Define an anastomosis in coronary circulation.

A junction between blood vessels that provides alternate pathways for blood flow.

Which side of the heart drives the pulmonary circuit, and what is its pressure characteristic?

Right side; short, low-pressure circuit.

Which side of the heart drives the systemic circuit, and what is its pressure characteristic?

Left side; long, high-pressure circuit.

Why does chronic hypertension strain the left ventricle?

Because the ventricle must generate higher force to eject blood into the high-pressure systemic circuit.

Name the two atrioventricular (AV) valves.

Tricuspid (right AV) and Bicuspid/Mitral (left AV) valves.

Name the two semilunar valves.

Pulmonary semilunar valve and Aortic semilunar valve.

What prevents backflow of blood within veins?

Venous valves

Which heart structure is the primary pacemaker and its intrinsic rate?

Sinoatrial (SA) node; ~75 beats per minute

Which node serves as a backup pacemaker at ~50 beats per minute?

Atrioventricular (AV) node

What is the only electrical connection between atria and ventricles?

Bundle of His (AV bundle)

Define arrhythmia.

An irregular heart rhythm due to defects in the intrinsic conduction system.

Why is ventricular fibrillation life-threatening?

Because ventricles quiver instead of pumping, stopping effective circulation.

Cardiac output formula

Cardiac Output = Heart Rate × Stroke Volume

Average resting cardiac output in an adult

Approximately 5 L/min

How much can cardiac output increase during strenuous exercise?

Up to about 5-times resting value (~25 L/min).

Which autonomic center decreases heart rate by acting on SA and AV nodes?

Cardio-inhibitory center (parasympathetic).

Define bradycardia.

Abnormally slow heart rate (<60 bpm).

Define tachycardia.

Abnormally fast heart rate (>100 bpm).

List the three tunics (layers) of a typical blood vessel (inner to outer).

Tunica intima, Tunica media, Tunica externa

Where does gas and nutrient exchange with tissues occur?

Capillaries

Why is vasodilation prominent in skin vessels?

To aid heat loss and cooling of the body.

Normal systemic arterial blood pressure (average adult).

120 mm Hg systolic / 80 mm Hg diastolic

Which fetal shunt connects pulmonary trunk to aorta?

Ductus arteriosus

Which fetal opening allows blood flow between right and left atria?

Foramen ovale

What is hematocrit?

Percentage of whole blood volume occupied by red blood cells.

Average male and female hematocrit values

Males ~47 % ±5 %; Females ~42 % ±5 %.

After centrifugation, which layer contains immune cells and platelets?

Buffy coat

Main protein in plasma and its percentage of plasma proteins

Albumin; ~60 % of plasma proteins

Life span of a typical red blood cell

About 3–4 months (120 days)

Why do mature RBCs lack nuclei and organelles?

To maximize space for hemoglobin and enhance oxygen transport.

Define hematopoiesis.

Formation of blood cells from hematopoietic stem cells in red bone marrow.

What risk accompanies abuse of erythropoietin (blood doping)?

Increased blood viscosity leading to heart attack or stroke.

Symptom expected in iron-deficiency anemia

Increased fatigue due to reduced oxygen-carrying capacity.

Percentage of WBCs in total blood volume

≈1 %

Name the granulocyte classes.

Neutrophils, Eosinophils, Basophils

Name the agranulocyte classes.

Lymphocytes, Monocytes

Which formed element fragments to form platelets?

Megakaryocytes (derived from hematopoietic stem cells).

Primary functions of blood (three broad categories)

Transport (nutrients, wastes, gases, hormones), Protection (immune, clotting), Regulation (temperature, pH, fluid volume).

Blood pH range compatible with life

7.35 – 7.45

Direction of arterial versus venous blood flow relative to the heart

Arteries carry blood away from the heart; Veins carry blood toward the heart.

Which pulmonary vessel is an exception to the usual oxygenation rule for arteries/veins?

Pulmonary artery (carries deoxygenated blood).