Circulatory System Overview

Circulatory System Overview

• The circulatory system provides the force (the heart) and channels (blood vessels) for moving blood throughout the body.
• Blood carries food, oxygen to cells, and removes waste products.
• The system comprises three primary cycles: coronary (heart), pulmonary (lungs), and systemic (body).

Circulation: The Double Pump

• Blood passes through the heart twice during a complete circuit.
• The right side of the heart receives deoxygenated blood from body tissues and pumps it to the lungs.
• The left side of the heart receives oxygenated blood from the lungs and pumps it to all body tissues.

Human Circulatory System

• Blood circulates within tubular blood vessels.
• Blood and body tissue cells do not directly contact each other.
• Blood vessels are found throughout the body enabling the exchange of vital materials, i.e., oxygen and nutrients.
• The circulatory system consists of blood vessels, blood, and the heart.

Blood Vessels

Arteries

• Thick-walled tubes made of elastic muscle tissue.
• Expand in response to pressure changes from the heart's pumping action.
• Carry blood away from the heart.
• Branch into smaller vessels called arterioles.
• The aorta is the main artery leaving the heart.

Veins

• Thin-walled tubes.
• Contain valves that prevent blood backflow due to low pressure.
• Carry blood back to the heart from body tissues.
• Small veins are called venules.
• The vena cava is the main vein entering the heart.

Capillaries

• Fine network of tubes surrounding body tissues.
• Thin walls (single cell layer) enable rapid diffusion of substances.
• Oxygen and nutrients pass from capillaries into body cells.
• Carbon dioxide and waste products pass from body cells into capillaries.

Blood

• An adult human with a 70 kg body weight has approximately 5 liters of blood.
• Blood is a fluid tissue with specialized cells working together.
• Blood is essential for transporting gases (oxygen and carbon dioxide), waste products, and nutrients.

Blood: The Transport Medium

• Blood also plays crucial roles in maintaining body functions and fighting diseases.
• Blood clotting is also one of the essential functions of the blood.

Blood Components

Red Blood Cells (Erythrocytes)

• Contain hemoglobin, an iron-containing protein, which carries oxygen.
• Produced in bone marrow and live for approximately 120 days.
• Body regulates red blood cell production in response to oxygen levels (e.g., high altitudes).
• Lack a nucleus.
• The most numerous type of blood cell.

White Blood Cells (Leukocytes)

• Fight germs and harmful foreign cells.
• Have a lifespan from a few days to a few weeks.
• Contain a nucleus.

Platelets

• Initiate blood clotting when there's a skin cut.

Blood Disorders

Anemia

• Insufficient hemoglobin reduces oxygen-carrying capacity.
• Leads to tiredness and low energy levels.
• Iron supplements may help.

Leukemia

• Cancer of the blood characterized by an increased number of immature white blood cells.
• Immature white blood cells are not capable of fighting disease.

The Heart

• Composed of cardiac muscle that beats involuntarily.
• Beats approximately 72 times per minute.
• Two sides beat in unison, separated by a muscular wall (septum).
• Systole is the heart muscle contraction; diastole is relaxation.

Heart Chambers

• Each side has an atrium (thin-walled, receives blood from veins) and a ventricle (thick-walled, delivers blood to arteries).
• The heart has four chambers in total.

Diseases and Disorders of the Circulatory System

Coronary Artery Disease

• Coronary arteries supply blood to the heart.
• Arteries can become partially blocked by plaque (fat, cholesterol, calcium).
• Symptoms can include tired, dizzy, pain or burning sensation in arms or chest.
• Angiograms are used for diagnosis.

Heart Attack

• Arteries can become completely blocked by plaque or a blood clot.
• Heart muscle cells lose oxygen and nutrients and may die.
• Symptoms include chest pain/pressure, shortness of breath, nausea, anxiety, sweating, and dizziness.
• Blood tests and electrocardiograms (ECGs) can assist in diagnosis.
• Heart attacks can be life threatening.

Explore the essential functions of the circulatory system, including the role of the heart, blood vessels, and blood in transporting oxygen and nutrients throughout the body. Learn about the three primary circulatory cycles: coronary, pulmonary, and systemic. This quiz provides insights into how blood circulates and its importance for bodily functions.