Cardiovascular Anatomy and Physiology

Mediastinum

The space within the thoracic cavity between the lungs where the human heart is located.

Pericardium

The protective sac surrounding the heart that separates it from other mediastinal structures and contains the pericardial cavity.

Hypertrophic cardiomyopathy

Abnormal enlargement of the heart muscle without a clear cause, potentially leading to unexplained death in healthy individuals.

Atria

Heart chambers that receive blood from either the systemic or pulmonary circuits.

Ventricles

Heart chambers responsible for pumping blood into either the systemic or pulmonary circuits.

Pulmonary trunk

Blood vessel carrying blood from the right ventricle to the lungs, branching into the pulmonary arteries.

Septum

A partition dividing the heart into chambers, including the interatrial and interventricular septum.

Valves

Specialized structures ensuring one-way blood flow in the heart, including atrioventricular and semilunar valves.

Coronary arteries

Blood vessels supplying the heart muscle (myocardium) with oxygenated blood.

Autorhythmicity

The ability of cardiac muscle to generate electrical impulses independently, regulating the heart's contraction rate.

Cardiac Cycle

The period from atrial contraction to ventricular relaxation.

Diastole

The relaxation phase when the heart chambers fill with blood.

Systole

The contraction phase when the heart pumps blood into circulation.

End Diastolic Volume (EDV)

Volume of ventricles before contraction.

End Systolic Volume (ESV)

Blood remaining in ventricles after contraction.

Stroke Volume

Amount of blood pumped by one ventricle.

Cardiac Output

Amount of blood pumped by each ventricle per minute.

Bradycardia

Resting heart rate below 60 BPM in adults.

Tachycardia

Resting heart rate above 100 BPM in adults.

Baroreceptor Reflex

Monitors blood pressure changes to maintain cardiac homeostasis.

Catecholamines

Epinephrine and Norepinephrine that increase depolarization rate.

Thyroxin

Increases heart rate and contractility by acting at the genome level.

Fibrillation

Quivering or irregular heart rhythm.

Hypokalemia

Low potassium levels leading to arrhythmias.

Hyperkalemia

High potassium levels causing the heart to become weak and flaccid, eventually failing.

Acidosis

Blood being too acidic.

Alkalosis

Blood being too alkaline, affecting enzyme function and heart rate.

Hyperthermia

Elevated body temperature increasing heart rate and contraction strength.

Hypothermia

Lowered body temperature slowing heart rate and contractions.

Preload

Stretch on the ventricles before contraction.

Sarcomeres

Basic contractile unit of a myocyte.

Frank-Starling mechanism

Force of heart contraction proportional to muscle fiber length.

Venous return

Blood flow from periphery back to the right atrium.

Contractility

Force of heart muscle contraction.

Afterload

Ventricular tension against vascular resistance for effective pumping.

Positive inotropic factors

Increase contractility (e.g., sympathetic stimulation).

Negative inotropic factors

Decrease contractility (e.g., parasympathetic stimulation).

Stroke volume

Determined by preload, contractility, and afterload.

Artery

Vessel carrying blood away from the heart.

Vein

Vessel returning blood to the heart.

Lumen

Hollow passageway for blood flow in vessels.

Vasa vasorum

Vessels within larger vessels distributing oxygen and nutrients.

Tunica intima

Innermost layer of veins/arteries regulating blood flow and pressure.

Tunica media

Middle layer with smooth muscle in veins/arteries.

Tunica externa

Outermost layer of veins/arteries preventing movement.

Elastic arteries

Close to the heart with elastic fibers in all tunics.

Muscular arteries

Further from the heart with more smooth muscle.

Arteriole

Small artery leading to capillaries, regulating blood flow.

Capillaries

Microscopic vessels supplying blood to tissues.

Perfusion

Process of supplying blood to tissues.

Continuous capillaries

Complete endothelial lining with tight junctions.

Fenestrated capillaries

Capillaries with pores in addition to tight junctions.

Sinusoid capillaries

Flattened capillaries with extensive gaps, found in specific organs.

Precapillary Sphincters

Control blood flow from metarterioles to thoroughfare channels when closed.

Arteriovenous Anastomosis

Direct connections between small arteries and veins.

Vasomotion

Irregular blood flow through capillary beds regulated by chemical signals.

Venules

Extremely small veins connecting capillary beds to larger veins.

Emigration/Diapedesis

Movement of leukocytes from circulation to tissues at venules.

Veins vs

Veins have thinner walls, larger lumens, and valves for unidirectional flow.

Venous Reserve

Blood stored in veins for redistribution in the body.

Capacitance Vessels

Veins, referred to as they can hold blood in addition to returning it to the heart.

Blood Flow

Movement of blood through vessels, tissues, or organs.

Blood Pressure

Force on blood vessel walls or heart chambers.

Systolic Pressure

Arterial pressure during ventricular contraction.

Diastolic Pressure

Arterial pressure during ventricular relaxation.

Pulse Pressure

Difference between systolic and diastolic pressure.

Mean Arterial Pressure (MAP)

Average blood pressure in arteries.

Ischemia

Insufficient blood flow leading to tissue damage.

Hypoxia

Inadequate tissue oxygenation.

Pulse

Expansion and recoil of arteries due to heart contraction.

Compliance

Ability of a compartment to expand with increased content.

Poiseuille's Equation

Describes blood flow in vessels based on pressure, radius, length, and viscosity.

Skeletal Muscle Pump

Increases venous pressure with muscle contraction to counteract gravity.

Vasomotor Centers

Control contraction of smooth muscle in the tunica media.

Baroreceptors

Specialized stretch receptors in the heart and blood vessels.

Atrial Reflex

Triggers sympathetic stimulation to increase cardiac output.

Chemoreceptors

Monitor blood levels of oxygen, carbon dioxide, and pH.

Endocrine Regulation

Involves hormones like catecholamines and interactions with the kidneys.

Renin-Angiotensin-Aldosterone Mechanism

Uses renin and angiotensin to regulate blood pressure.

Autoregulation of Perfusion

Relies on local self-regulatory mechanisms.

Chemical Signals

Regulate opening and closing of precapillary sphincters.

Myogenic Response

Reaction to stretching of smooth muscle in arterioles.

Circulatory Shock

Condition where the circulatory system can't maintain blood flow.

Role of Circulatory System in Digestive System

Absorbs nutrients and water.

Role of Circulatory System in Endocrine System

Delivers hormones for homeostasis.

Role of Circulatory System in Integumentary System

Carries clotting factors and regulates temperature.

Role of Circulatory System in Lymphatic System

Transports white blood cells and excess fluid.

Role of Circulatory System in Muscular System

Provides nutrients for contraction.

Role of Circulatory System in Nervous System

Regulates cardiac output and blood flow.

Role of Circulatory System in Respiratory System

Facilitates gas exchange.

Role of Circulatory System in Skeletal System

Provides minerals for bone matrix.

Development of Blood Vessels

Establishment of fetal circulation patterns.

Blood as Connective Tissue

Made up of cellular elements and an extracellular matrix.

Cellular Elements

The formed elements in blood, including red blood cells (RBCs), white blood cells (WBCs), and platelets.

Platelets

Cell fragments involved in blood clotting.

Extracellular Matrix

Plasma, the liquid component of blood.

Primary Function of Blood

To deliver oxygen, nutrients, and remove wastes from body cells.

Blood Defense

White blood cells (WBCs) protect the body from external and internal threats.

Blood Homeostasis

Blood regulates body temperature, chemical balance, and water content.

Hematocrit

A test measuring the percentage of red blood cells (RBCs) in blood.