Unit D2 Study Guide

Unit D2: Human Systems – Circulatory & Immune Systems

General Outcome

  • Students will explain the role of the circulatory and defense systems in maintaining internal equilibrium.

Specific Outcomes

  • Identify the principal structures of the heart and associated blood vessels:

    • Atria

    • Ventricles

    • Septa

    • Valves

    • Aorta

    • Venae Cavae

    • Pulmonary Arteries and Veins

    • Sinoatrial Node

    • Atrioventricular Node

    • Purkinje Fibres

  • Describe the action of the heart, blood pressure, and circulation of blood through coronary, pulmonary, and systemic pathways.

  • Describe the structure and function of blood vessels:

    • Arteries

    • Veins

    • Capillaries

  • Describe the main components of blood and their roles in transport, clotting, and resisting pathogens:

    • Plasma

    • Erythrocytes

    • Platelets

    • Leucocytes

  • Explain the role of the circulatory system at the capillary level in facilitating energy and matter exchange with other body systems.

  • Explain the role of blood in regulating body temperature.

  • Describe the function of the lymphatic system in general terms.

  • List the main cellular and non-cellular components of the human defense system and describe their roles:

    • Skin

    • Macrophage

    • Helper T Cell

    • B Cell

    • Killer T Cell

    • Suppressor T Cell

    • Memory T Cell

  • Describe ABO and Rh blood groups based on antigens and antibodies.

Part 1: Circulatory System

Structures of the Circulatory System

  • Components:

    • Blood Vessels

    • Blood

    • Heart

  • Functions:

    • Transport: Gases, nutrients, waste materials

    • Homeostasis: Regulates internal temperature and transports hormones

    • Protection: Against blood loss and disease

Blood Vessels

Types of Blood Vessels

  1. Arteries:

    • Carry oxygen-rich blood away from the heart

    • Thick, muscular, elastic walls, able to withstand high blood pressure

  2. Veins:

    • Carry oxygen-poor blood back to the heart

    • Thinner walls with valves to prevent backflow, lower blood pressure

  3. Capillaries:

    • Tiny vessels (one cell thick) for gas and nutrient exchange with tissues

Page 3: The Heart

Location

  • Slightly left of the center of the chest

Functions

  • Pumps blood through the body

  • Keeps oxygen-rich and oxygen-poor blood separated

  • Ensures blood flows only in one direction

Structure

  • Composed of cardiac muscle, chambers (2 atria, 2 ventricles), and valves.

Page 4: Heart Valves

Types of Valves

  • Atrioventricular Valves:

    • Tricuspid Valve (right atrium and ventricle)

    • Bicuspid Valve (left atrium and ventricle)

  • Semilunar Valves:

    • Pulmonary Semilunar Valve (right side)

    • Aortic Semilunar Valve (left side)

Pathways of the Circulatory System

  1. Pulmonary Pathway: Blood to and from lungs.

  2. Systemic Pathway: Blood to and from rest of the body.

  3. Coronary Pathway: Blood supplying the heart itself.

Page 5: Blood Flow Through the Heart

  1. Deoxygenated blood enters right atrium via superior and inferior vena cava.

  2. Moves through tricuspid valve into right ventricle.

  3. Pumped through pulmonary valve into pulmonary arteries (only arteries carrying deoxygenated blood).

  4. In lungs, oxygen diffuses into blood.

  5. Blood returns via pulmonary veins (only veins carrying oxygenated blood).

  6. Enters left atrium, moves through bicuspid valve into left ventricle.

  7. Oxygenated blood pumped through aortic valve into aorta.

  8. Deoxygenated blood returns after oxygen usage.

The Beating Heart

  • SA Node: Pacemaker, sets rhythm of about 70 beats per minute.

  • Conducts electrical signals through atria to AV node, then to ventricles via Bundle of His and Purkinje fibers.

Page 6: Sounds of the Heart and Blood Pressure

  • Heart sounds are from valve closure:

    • Lub: Atrioventricular valves closing.

    • Dub: Semilunar valves closing.

  • Blood Pressure: Pressure in vessels, changes with heartbeat.

    • Systolic Pressure: Max pressure during contraction.

    • Diastolic Pressure: Min pressure during relaxation.

Page 7: Measuring Blood Pressure

  • Measured using sphygmomanometer (blood pressure cuff).

  • Average resting: 120/80 mmHg, normal pulse 70-75 beats/min.

  • Higher during exercise due to increased cardiac output (stroke volume x heart rate).

Page 8: Cardiovascular Disorders

  • Major Disorders:

    • Congenital heart defects (e.g. murmurs, holes in the heart)

    • Hypertension (silent killer, can cause ruptured vessels)

    • Aneurysms (bulges in weak vessel walls)

    • Arteriosclerosis (thickening/hardening of arteries)

    • Heart Attack (myocardial infarction).

  • Treatments: Angioplasty, bypass surgery.

Page 9: Blood Composition

Components

  1. Plasma (55%): Fluid medium for blood cells.

    • Contains water, gases, proteins, sugars, vitamins, and waste.

  2. Formed Elements (45%):

    • Red Blood Cells (erythrocytes), White Blood Cells (leukocytes), Platelets (thrombocytes).

    • Functions: Transport gases, immune response, clotting.

Page 10: Blood Summary

Cell Types

Cell Type

Origin

Average Count (mm³)

Functions

Life Span

Appearance

Red Blood Cells

Red bone marrow

5,500,000 (male)

Transport oxygen

120 days

Biconcave, no nucleus

White Blood Cells

Red bone marrow

6000

Immune response

Few hours - days

Colorless, with nucleus

Platelets

Bone marrow

250,000

Blood clotting

Few days

Cell fragments, no nucleus

Page 11: Blood Disorders

  • Anemia: Low red blood cells or hemoglobin.

  • Hemophilia: Insufficient clotting proteins, hereditary.

  • Leukemia: Cancer of white blood cells.

Page 12: Lymphatic System

  • Network of vessels aiding in fluid balance and immune defense.

    • Collects interstitial fluid, forming lymph.

    • Houses lymphocytes for filtering bacteria.

Page 13: Defense Systems

Antigens and Antibodies

  • Antigens: Surface molecules on cells/pathogens.

  • Antibodies: Proteins produced by immune cells to neutralize pathogens.

Lines of Defense

  1. First Line: Physical barriers (skin, mucus, etc.).

  2. Second Line: Non-specific defenses (inflammatory response).

  3. Third Line: Specific defenses (antibody-mediated immunity).

Page 14: How Antibody-Mediated Immunity Works

Lymphocyte Functions

  • T-Cells: Identify and kill infected cells.

  • B-Cells: Produce antibodies for targeting pathogens.

Page 15: Blood Types

Compatibility

  • Antigens determine blood type compatibility.

  • Universal Donor: O- (no antigens).

  • Universal Recipient: AB+ (no antibodies).

Page 16: The Rh Factor

  • Presence or absence of Rh antigen affects blood compatibility.

  • Risk of hemolytic disease in subsequent pregnancies with Rh incompatibility.

Page 17: Immune System Disorders

Types

  • Autoimmune Diseases: Immune system attacks body cells.

  • Allergies: Immune response to harmless materials.

  • Immunodeficiency: Reduced immune system effectiveness (e.g., AIDS).