1. Chapter 8 - circulation (1)

Chapter 8: The Heart

• Superior Vena Cava: Brings blood from the head and arms to the heart.

• Inferior Vena Cava: Brings blood from the body and legs to the heart.

• Aortic Arch: Distributes oxygen-rich blood from the heart to the body.

• Pulmonary Arteries: Carry deoxygenated blood from the heart to the lungs.

• Pulmonary Veins: Carry oxygenated blood from the lungs back to the heart.

Page 2: Overview of Circulatory System

• Key Objectives:

  • Identify major structures of the circulatory system.

  • Describe the structure and function of blood vessels.

  • Explain heart action and blood circulation.

  • Investigate heart rate, blood pressure, and their relationship with exercise.

  • Identify circulatory system disorders.

Page 3: Main Functions of the Circulatory System

• The circulatory system has three primary functions:

  • Transportation: Delivers oxygen and nutrients to cells, removes waste products.

  • Temperature Regulation: Maintains stable internal body temperature.

  • Protection: Prevents blood loss and combats infections.

Page 4: The Human Heart

• Structure: Muscular organ roughly the size of a fist, encased in a fluid-filled membrane (pericardium).

• Tissue: Comprised of cardiac muscle tissue, which contracts involuntarily.

Page 5: Heart Chambers

• Four Chambers:

  • Two Atria (upper, left and right sides)

  • Two Ventricles (lower, left and right sides)

• Septum: Thick wall separating the right and left chambers of the heart.

Page 6: Circulation in the Heart

• Blood flow pathway through the heart and associated veins/arteries (e.g., superior vena cava, aorta, pulmonary arteries and veins).

Page 7: Role of Valves

• Valves: Ensure unidirectional blood flow.

  • Atrioventricular Valves: Separates atria and ventricles;

    • Right Side: Tricuspid valve (3 flaps)

    • Left Side: Bicuspide valve (2 flaps)

  • Semilunar Valves: Located at the exit of ventricles.

Page 8: Blood Vessel Structures

• Types of Blood Vessels:

  • Arteries: Carry blood away from heart; possess elastic walls to manage high pressure.

  • Veins: Carry blood towards heart; thinner walls, larger diameter, and contain one-way valves to prevent backflow.

Page 9: Capillaries

• Capillary Structure:

  • Connect arteries and veins.

  • Facilitate gas and nutrient exchange due to thin walls (one layer of cells).

Page 10: The Beating Heart

• Electrical Signals: Control heartbeat; the SA node serves as the heart's pacemaker.

  • SA node initiates contraction in the right atrium; signals transmitted to AV node and then through the Bundle of His and Purkinje fibers.

Page 12: Electrocardiogram (ECG)

• Heart Activity Recording: Measures electrical activity with three primary waves — P wave (atria contraction), QRS complex (ventricular contraction), and T wave (ventricular recovery).

Page 16: Heart Sounds

• S1 (Lub): Closing of atrioventricular valves.

• S2 (Dub): Closing of the semilunar valves.

• Murmurs: Occur if valves do not close properly.

Page 17: Blood Pressure

• Measurement: Pressure against vessel walls; varies between systolic (maximum) and diastolic (minimum) during heartbeats.

• Healthy reading: 120/80.

Page 19: Cardiac Output

• Definition: Volume of blood pumped from each side of the heart per minute.

  • Cardiac Output Formula: Heart Rate x Stroke Volume.

  • Average cardiac output ~5L/min.

Page 22: Cardiovascular Disorders

• Leading Cause of Death: Cardiovascular disease; risk factors include smoking, poor diet, and lack of exercise.

• Atherosclerosis: Buildup of plaque in arteries leading to reduced blood flow and potential blockages.

Page 25: Blood Components

• Blood Composition:

  • Fluid Portion: Plasma (55% volume)

  • Solid Portion: Formed elements (45% volume), including red blood cells, white blood cells, and platelets.

Page 29: Erythrocytes (Red Blood Cells)

• Function: Oxygen transport; lack a nucleus and have a lifespan of about 120 days.

• Anemia: Condition marked by reduced red blood cells or hemoglobin.

Page 30: Leukocytes (White Blood Cells)

• Function: Immune response; produced in bone marrow.

  • Types include granulocytes, monocytes, and lymphocytes.

Page 31: Platelets

• Role: Essential for blood clotting; respond to injury by forming clots to prevent blood loss.

Page 35: Blood Types

• ABO System: Classification based on antigens present on red blood cells; involves types A, B, AB, and O, each with specific antibodies.

Page 40: Blood Disorders

• Hemophilia: Genetic disorder leading to inadequate clotting factors.

• Leukemia: Cancer of white blood cells characterized by abnormal proliferation of immature blood cells.

Page 42: Lymphatic System

• Function: Maintains fluid balance and protects the body via lymph collection and white blood cell proliferation.

Page 43: Human Defense System

• First Line of Defense: Skin and mucus preventing pathogen entry.

Page 46: Non-Specific Defenses

• Cell-mediated Immunity: Phagocytosis by neutrophils and macrophages.

Page 47: Specific Defenses

• Antibody-Mediated Immunity: Involves lymphocytes recognizing and responding to foreign substances.

Page 49: Antigens and Antibodies

• Antigens allow for immune recognition; antibodies help neutralize pathogens.

Page 55: Immune System Disorders

• Autoimmune Disorders: Immune system mistakenly attacks body cells.

• Allergies: Exaggerated immune responses to non-harmful substances.