Circulatory-System

Circulatory System Overview

  • Major components of the circulatory system include:

    • Superior vena cava

    • Inferior vena cava

    • Aorta

    • Pulmonary veins

    • Pulmonary arteries

    • Femoral artery

    • Femoral vein

    • Descending aorta

Functions of the Circulatory System

  • Main Functions:

    • To carry nutrients to all body cells (e.g. glucose, amino acids, oxygen)

    • To carry wastes away from all body cells (e.g. ammonia, carbon dioxide)

  • Circulating Fluid:

    • Blood flows through flexible pipe-like structures called vessels to move throughout the body.

Components of the Human Circulatory System

  • Consists of:

    • Heart: Pumps the blood

    • Blood Vessels: Conduct blood flow

    • Blood: Substance that carries materials being transported.

The Heart

  • Location: Near the center of the chest

  • Size: Approximately the size of a clenched fist

  • Chambers: Four chambers

    • Atrium: Upper chambers receiving blood

    • Ventricle: Lower chambers pumping blood

Cardiac Circulation

  • The heart acts as two separate pumps:

    • Right Side: Pumps blood from the heart to the lungs (pulmonary circulation)

      • In lungs, CO2 leaves blood and O2 is absorbed.

    • Left Side: Pumps blood from the heart to the rest of the body (systemic circulation).

Blood Flow and Valves

  • Blood flow pathway includes:

    • Right Atrium (RA) -> Tricuspid valve -> Right Ventricle (RV) -> Pulmonary Valve -> Pulmonary Arteries (PA) -> Lungs

    • Left Atrium (LA) -> Mitral Valve -> Left Ventricle (LV) -> Aortic Valve -> Aorta (AO).

  • Blood types: Oxygen-rich and oxygen-poor blood.

Blood Vessels

  • Three Types:

    • Arteries: Carry blood away from the heart (except pulmonary arteries, which carry oxygen-poor blood).

      • Thick walls withstand pressure from heart contractions; contain connective tissue, smooth muscle, and endothelium.

    • Veins: Carry blood toward the heart; usually carry oxygen-poor blood.

      • Walls contain connective tissue and smooth muscle; valves present to keep blood flowing toward the heart.

    • Capillaries: Smallest blood vessels connecting arteries and veins.

      • Walls are one cell thick; blood cells pass through in single file.

Diseases of the Circulatory System

  • Known as: Cardiovascular diseases.

  • Major Concerns: Heart disease and stroke are leading causes of death and disability, particularly in the Philippines.

Specific Diseases

  • High Blood Pressure (Hypertension):

    • Forces the heart to work harder, can weaken heart muscle and blood vessels.

    • Increases risk of coronary heart disease, heart attack, or stroke.

  • Heart Disease:

    • Narrowing of blood vessels can lead to heart attacks (symptoms: nausea, shortness of breath, severe chest pain).

    • Blood clots resulting from atherosclerosis can cause strokes due to oxygen deprivation in the brain.

Preventing Diseases

  • Healthy Lifestyle Recommendations:

    • Regular exercise

    • Balanced diet:

      • Fruits & Vegetables (33%)

      • Cereal, Bread & Potatoes (33%)

      • Milk and Dairy Foods (15%)

      • Meat, Fish & Alternatives (12%)

      • Fatty & Sugary Foods (7%)

    • Avoid smoking

Blood Composition

  • Overall Volume: Human body contains 4-6 liters of blood.

    • Components:

      • Red Blood Cells (RBCs)

      • White Blood Cells (WBCs)

      • Platelets

      • Plasma (55% of blood volume; straw-colored fluid)

Plasma

  • Composed of:

    • 90% Water

    • 10% dissolved gases, salts, nutrients, enzymes, hormones, wastes, and plasma proteins.

Red Blood Cells (Erythrocytes)

  • Most numerous cells in blood, transport oxygen.

  • Color derived from hemoglobin (iron-containing protein that binds with oxygen).

  • Shape: Round plates with a central indentation.

White Blood Cells (Leukocytes)

  • No hemoglobin; produced in bone marrow.

  • Important for fighting diseases by targeting pathogens.

Platelets

  • Essential for blood clotting, playing a key role in preventing excessive bleeding.