Human Transport in Humans: Cardiovascular System

Human Transport in Humans

• The cardiovascular system is responsible for transporting oxygen and nutrients to cells, and removing carbon dioxide and waste products.
• This system consists of the heart, blood vessels, and blood.

Learning Objectives

• Blood composition and functions
• Blood clotting process
• Cardiovascular system
  • Heart structure
  • Major blood vessels and flow
  • Pulmonary and systemic circuits

Cardiovascular System

• Components:
  • Heart
  • Blood Vessels
  • Blood

Functions of the Cardiovascular System

• Transports oxygen and nutrients to cells.
• Removes carbon dioxide and waste products from cells.

Blood Characteristics

• Thicker than water
• Heavier than water
• Oxygen content determines color
• Males (5-6 liters), females (4-5 liters) on average

Blood and Blood Cells

• Blood is a tissue of fluid (plasma) and cells.
• Plasma (55% of blood volume): fluid containing dissolved salts, sugars, proteins, and more.
• Formed elements (45% of blood volume):
  • Red blood cells (RBCs): transport oxygen using hemoglobin.
  • White blood cells (WBCs): involved in defense and immunity.
  • Platelets: involved in blood clotting.

Plasma Proteins

• Albumin (58%): maintains water balance.
• Globulins (38%): involved in the immune system.
• Fibrinogen (4%): aids in clot formation.

Erythrocytes (Red Blood Cells)

• Disk-shaped, with thick edges.
• Function: Transport oxygen to tissues.
• Produced in bone marrow
• Lose nuclei and mitochondria, creating more space for hemoglobin
• Live for 3-4 months (120 days)
• Filtered out by the liver
• ~3 million RBC's destroyed each second

Hemoglobin

• Primary component of red blood cells.
• Transports oxygen.
• Each globin protein is attached to a heme molecule.
• Each heme contains one iron atom.
• Oxygen binds to iron, forming oxyhemoglobin.

Leukocytes (White Blood Cells)

• Lack hemoglobin.
• Larger than erythrocytes.
• Contain a nucleus.
• Function: Fight infections and remove dead cells and debris by phagocytosis.

Types of Leukocytes

• Neutrophils: Most common, defend against bacterial and fungal infections; phagocytes.
• Eosinophils: Deal with parasitic infections and allergic reactions.
• Basophils: Short-term inflammatory response, release histamine.
• Monocytes: Large leukocytes, differentiate into macrophages.
• Lymphocytes: Involved in the immune response; B cells and T cells lead to antibody production.

Platelets

• Involved in blood clotting.
• Produced in red bone marrow.

Blood Cell Production

• Stem cells ("parent" cells) in bone marrow differentiate into many types of blood cells, including white blood cells, red blood cells, and platelets.

Blood Clotting

• Series of steps to seal holes in damaged blood vessels
• Chemical signals initiate the process.
• Platelets form a plug.
• Seal reinforced by fibrin clot.

Steps in Clot Formation

• Injury to a blood vessel releases prothrombin activator.
• Prothrombin activator activates prothrombin.
• Thrombin activates fibrinogen into its active form, fibrin.
• Fibrin forms a network that traps blood (clots).

Circulatory System in Animals

• Function: Transport fuel (sugars), oxygen, and removes waste (CO2).
• Systems involved: Digestive, respiratory, and circulatory systems
• Picks up and delivers supplies & wastes around the body.

Circulatory System

• Made up of three parts:
  • Organ (heart)
  • Tissues & cells (blood)
  • Blood vessels

Function of the Heart

• Regulates blood supply.
• Generates blood pressure.
• Routes blood.
• Ensures 1-way blood flow.

Heart Characteristics

• Size: Approximately a fist size.
• Location: Between the lungs in the thoracic cavity.
• Orientation: Apex (bottom) is pointed towards the left side.

Heart: 4 Chambered Heart

• Atria (thin walls): Collect blood.
• Ventricles (thick walls): Pump blood out.

Atria

• Collection chambers
• Thin walled
• Push blood into ventricles

Ventricles

• Pumping chambers
• Thick walls
• Contract forcefully to propel blood out of the heart

Heart Chambers & Blood Vessels

• Four Chambers: Left atrium, right atrium, left ventricle, right ventricle.
• Coronary sulcus: Separates atria from ventricles

Valves (Heart)

• Structures that ensure one-way blood flow.
• Atrioventricular (AV) valves: Tricuspid and Bicuspid (Mitral) valves
• Chordae tendinae: attach to AV valves to support them.
• Semilunar valves: Pulmonary and Aortic valves located at bases of pulmonary trunk and aorta

Arteries

• Blood flows away from the heart.
• Thicker walls provide strength for high pressure pumping of blood.
• Elastic and stretchable to maintain blood pressure even when heart relaxes.

Veins

• Blood returns to the heart.
• Thinner walls than arteries compared to arteries.
• Blood travels at low speed and pressure
• Valves support one-way flow of blood towards the heart

Major Veins

• Superior vena cava (from upper body)
• Pulmonary veins (from lungs)
• Inferior vena cava (from lower body)

Capillaries

• Very thin walls, facilitating the exchange of materials across the capillary walls.

Major Arteries

• Aorta
• Pulmonary artery
• Coronary arteries

Capillary function

• Exchange of materials between blood and tissues (O2, CO2, H2O, food, waste)
• Blood flow controlled by pre-capillary sphincter valves

Capillary Beds

• At any given time, only 5-10% of the body's capillaries have blood flowing through them.

Blood Flow

• Arteries → Arterioles → Capillaries → Venules → Veins → Heart

Circulation to Lungs & Circulation to Body

• Two parts, circulation pathways deliver oxygen to the body and waste removal to the lungs.

Evolution of Circulatory Systems

• Not all animals have four-chambered hearts.
• Advantages of four chambers: Increased efficiency, Separation of oxygenated and deoxygenated blood, creating higher pressure to pump blood for greater energy demands.

Cardiac Cycle (Heart)

• Complete sequence of heart pumping, contraction phase (systole), and relaxation phase (diastole).
• Atria & ventricles contract and relax in a coordinated manner to pump blood through the body

The Heart: Heart Sounds

• One cardiac cycle produces two heart sounds (lub and dub).
• Lub: When ventricles contract and atrioventricular (AV) valves snap shut.
• Dub: When ventricles relax and the pulmonary and aortic valves snap shut.

Explore the human cardiovascular system in this quiz. Learn about the structure and functions of the heart, the major blood vessels, and the blood's role in transporting oxygen and nutrients. Test your knowledge on blood composition, clotting, and the pulmonary and systemic circuits.