Cardiovascular System Heart Vasculature and Blood Major Components

Cardiovascular System Heart, Vasculature, and Blood

Major Components of the Human Cardiovascular System • Heart • Arteries and Veins • Blood

Simple Diagram of Heart Indicating Blood Flow Through the Heart Chambers

Alternate Diagram of the Heart

External Anatomy of the Heart

Animation of the Human Heart

Electrical Control of the Heart

Electrical Control of the Heart • SA node is the pacemaker of the heart. This node initiates the start of a heart beat and controls primarily the atrial contractions. • AV node is the site that controls the strong ventricular contractions of the heart and receives the signal to start from the SA node. • Purkinje fibers spread the electrical stimuli throughout the ventricles.

ECG (Electrocardiogram)

The Way Med Students Study Heart Rhythms

Flow of Blood through Heart, Lungs, and other Organs

Direction of Blood Flow • Oxygen-poor venous blood from the body empties into the right atrium • Blood from the right atrium is pumped into the right ventricle • Blood from the right ventricle is pumped into the lungs to be enriched with oxygen • Oxygen-rich blood from lungs is transported into the left atrium • Blood from the left atrium is pumped into the left ventricle • Oxygen-rich blood from the left ventricle is pumped throughout the body

Not much go Low on O (oxygen) Gotta get some Right Action (Right Atrium) Gonna go straight down to a cool new place Rockin Vibes (Right Ventricle) take me to a good gas place (lungs) After leaving the lungs without a care I fill a new room with Lovely Air (Left Atrium) After dropping straight down to another part Leaving Vegas (Left Ventricle) and now my heart Another way of learning how blood travels through the heart

Arteries and Veins • Arteries take blood away from the heart • Almost always arteries carry oxygen-rich blood (only exception is the pulmonary artery) • Veins take blood to the heart • Almost always veins carry oxygen -poor blood (only exception is the pulmonary vein)

Arteries and Veins (continued) • Arteries contain smooth muscle to pump blood throughout the body • Veins contain “back-flow” valves to prevent blood from going backwards • Capillaries are small blood vessels that act as the connection points between arteries and veins

Illustration of arteries and veins of the head and neck (including nerves)

Cardiovascular System Blood

Blood (General Facts) • Blood cells are made in adult red bone marrow while blood cells in the fetus are made in the fetal liver • Variety of blood cells serve different functions • Blood also contain non-cellular components including a variety of chemicals that are either needed by the body or need to be eliminated from the body (commonly known as plasma)

Common Blood Cell Types • RBCs (Red blood cells or erythrocytes) • WBCs (White blood cells or leukocytes) • Macrophages • Platelets

Red Blood Cells (RBCs) • Made in adult red bone marrow • RBCs lose their nuclei before entering the blood stream • Principle function is to help transport CO 2 to the lungs and take O 2 out of the lungs • O 2 and CO 2 are carried by the molecule hemoglobin (contains iron) inside the RBCs • RBCs last approximately 120 days in the blood stream • Spleen can act to take old RBCs out of the blood (although there are other mechanisms because we can live without a spleen)

Structure of Hemoglobin (Remember that it is the iron (Fe) that will bind O 2 and CO 2)

Binding of Gases to Hemoglobin • Oxygen (O 2) will bind tighter to the iron in hemoglobin than carbon dioxide • In the lungs the oxygen binds to hemoglobin and the carbon dioxide (CO 2) is removed to be cleared out of the lungs • Carbon monoxide (CO) binds better to hemoglobin than oxygen and prevents oxygen from binding to hemoglobin • Carbon monoxide poisoning results when oxygen is prevented from getting into cells (can lead to death)

Blood Types • Four most common blood types are O, A, B, and AB • A person with Type O blood can serve as a universal donor (Can be used by anyone with Type O, A, B, or AB blood) • A person with Type AB blood can act as a universal recipient (can receive O, A, B, or AB blood) • One additional blood factor called the Rh factor is important in pregnancy • The typing of blood is important when giving blood transfusions

Red Blood Cell Pathologies • Anemia—Variety of causes however, the major result is a decreased ability of the blood to carry oxygen throughout the body • Sickle Cell Anemia—Results from an abnormal protein causing a sickle shape in the red blood cells and causing decreased ability to carry oxygen throughout the body

White Blood Cells (WBCs) • • Much less in number than RBCs Commonly called leukocytes Comprised of neutrophils; T & B cells Neutrophils are responsible for removing harmful bacteria and other foreign particles • T & B cells are involved in the formation of antibodies and the immune response • Variety of leukemias (cancer of the blood) are the most common type of white blood cell pathology

Macrophage • Macrophages are derived from a particular type of circulating blood cell (megakaryocyte) • Macrophages reside in a variety of organs (e. g. , lung and liver) • Macrophages usually do not circulate continuously through the blood • Major role of macrophages are to remove harmful bacteria and other foreign particles from the organ

Platelets • Platelets are small cell fragments that contain important chemicals for the formation of blood clots • Platelets also can be given to individuals that have low platelet numbers (e. g. , thrombocytopenia) • Platelets are critical for wound repair and the prevention of blood loss • Many genetic disorders are those that have altered clotting ability • Platelets can also be involved in some pathological conditions (e. g. , atherosclerosis)