Circulatory and Lymphatic Systems

Flashcards based on lecture notes about the circulatory and lymphatic systems, covering topics such as blood vessels, heart structure, cardiac cycle, and blood components.

Closed Circulatory System

Blood is always enclosed in vessels as it circulates.

Double Circulatory System

Blood passes through the heart twice in one complete circuit around the body.

Pulmonary Circulation

Carries deoxygenated blood to the lungs to pick up oxygen and release carbon dioxide.

Systemic Circulation

Carries oxygenated blood from the heart to the body and returns deoxygenated blood.

Pulmonary Artery

Carries deoxygenated blood away from the heart to the lungs.

Pulmonary Vein

Carries oxygenated blood back to the heart from the lungs.

Aorta

Largest artery, carries blood to the body.

Vena Cava

Brings blood back to the heart (superior = from upper body, inferior = from lower body).

Pericardium

Tough, double-walled sac enclosing the heart.

Coronary Arteries & Veins

Supply the heart muscle (myocardium) with oxygenated blood.

Right Atrium

Receives deoxygenated blood from the vena cava.

Right Ventricle

Pumps deoxygenated blood to the lungs via the pulmonary artery.

Left Atrium

Receives oxygenated blood from the lungs via the pulmonary veins.

Left Ventricle

Pumps oxygenated blood to the body via the aorta.

Tricuspid Valve

Between right atrium and right ventricle.

Bicuspid (Mitral) Valve

Between left atrium and left ventricle.

Pulmonary Semilunar Valve

At the base of the pulmonary artery.

Aortic Semilunar Valve

At the base of the aorta.

Septum

Thick wall separating right and left sides of the heart.

Chordae Tendineae

String-like structures holding valves in place.

Papillary Muscles

Anchor chordae tendineae.

Arteries

Carry blood away from the heart.

Veins

Carry blood toward the heart.

Capillaries

Exchange of gases, nutrients, and waste between blood and tissues.

Right Atrium Function

Receives deoxygenated blood from the body via the vena cava.

Right Ventricle Function

Pumps deoxygenated blood to the lungs via the pulmonary artery.

Left Atrium Function

Receives oxygenated blood from the lungs via the pulmonary veins.

Left Ventricle Function

Pumps oxygenated blood to the body via the aorta.

Tricuspid Valve Function

Between right atrium and right ventricle; prevents backflow into atrium.

Bicuspid (Mitral) Valve Function

Between left atrium and left ventricle; prevents backflow into atrium.

Pulmonary Valve Function

At base of pulmonary artery; stops blood re-entering ventricle.

Aortic Valve Function

At base of aorta; stops backflow from aorta.

Aorta Function

Carries oxygenated blood from left ventricle to body.

Pulmonary Artery Function

Carries deoxygenated blood from right ventricle to lungs.

Pulmonary Veins Function

Bring oxygenated blood from lungs to left atrium.

Superior Vena Cava Function

Brings deoxygenated blood from upper body to right atrium.

Inferior Vena Cava Function

Brings deoxygenated blood from lower body to right atrium.

Cardiac Cycle

Sequence of events that occurs during one complete heartbeat.

Atrial Systole

Atria contract, blood is pushed into ventricles.

Ventricular Systole

Ventricles contract, blood is pumped to pulmonary artery and aorta.

Diastole

Both atria and ventricles relax, heart is filling with blood.

"Lub" Sound

Closing of AV valves (start of ventricular systole).

"Dub" Sound

Closing of semilunar valves (start of diastole).

Myogenic Control

Heartbeat originates within the heart muscle itself.

SA Node (Sinoatrial Node)

Located in right atrium; initiates electrical impulses that cause atria to contract.

AV Node (Atrioventricular Node)

Receives impulse from SA node; delays signal slightly, then passes it to the ventricles.

Bundle of His

Conducts impulses from AV node down the interventricular septum.

Purkinje Fibers

Spread impulses through ventricles → ventricular contraction.

Sympathetic Nerve Effect

Increases heart rate (during stress/exercise).

Parasympathetic (Vagus) Nerve Effect

Decreases heart rate (during rest/sleep).

Adrenaline (Epinephrine) Effect

Increases heart rate and strength of contraction.

Blood

A fluid connective tissue that transports substances throughout the body.

Plasma

Yellow fluid, mostly water with proteins, nutrients, hormones, wastes; transports substances and maintains blood pressure.

Red Blood Cells (RBCs) / Erythrocytes

Biconcave, no nucleus, contains hemoglobin; carries oxygen and some CO₂.

White Blood Cells (WBCs) / Leukocytes

Larger, with nuclei; several types; defend against infection and disease.

Platelets / Thrombocytes

Cell fragments; help in blood clotting (prevent bleeding).

Lymph

A clear fluid derived from plasma that circulates in the lymphatic system.

Lymph

Clear fluid with fewer proteins than plasma; contains WBCs (mainly lymphocytes).

Lymphocytes

Type of WBC involved in immune response.

Lymph Nodes

Small structures that filter lymph and house immune cells.

Lymphatic Vessels

Network of vessels that collect and transport lymph from tissues back to the bloodstream.

Lacteals

Lymph vessels in intestinal villi that absorb fats from the digestive system.

Lymphatic System Function: Fluid Balance

Collects excess tissue fluid that leaks out of blood capillaries.

Lymphatic System Function: Immune Support

Lymph nodes filter lymph to trap and destroy pathogens; provides a site for immune cell activation.

Lymphatic System Function: Absorbs and Transports Fats

Lacteals absorb dietary fats and fat-soluble vitamins for delivery into the bloodstream.

Lymphatic System Function: WBC Transport

Moves white blood cells throughout the body for pathogen detection and destruction.

Lymphatic System Function: Protein Return

Returns leaked plasma proteins to the bloodstream to maintain osmotic balance.