Introduction to the Cardiovascular System

Introduction to the Human Cardiovascular System

• The cardiovascular system is the body's transport system, carrying blood, heart, and blood vessels.
• This system delivers nutrients and removes waste products from body tissues.
• The transport medium is liquid blood flowing inside a closed tubular system.

Function of the Cardiovascular System

• Transports nutrients and hormones.
• Removes waste products from the body.
• Facilitates gaseous exchange (oxygen and carbon dioxide).
• Supports immune function.
• Blood vessels carry blood, oxygen, carbon dioxide, nutrients, and waste.
• The heart pumps blood through the blood vessels.

Components of the Cardiovascular System

• Blood
• Heart
• Blood vessels

Blood

• Composed of blood cells and plasma.
  • Erythrocytes (Red Blood Cells)
  • Leukocytes (White Blood Cells)
  • Thrombocytes (Platelets)
• Plasma is the fluid portion of blood.

Heart

• A four-chambered, hollow muscular organ, about the size of a fist.
• Located superior to the diaphragm, left of the midline, and anterior to the vertebral column, behind the sternum.

Functions of the Heart

• Generates blood pressure.
• Routes blood between pulmonary and systemic circulations.
• Ensures one-way blood flow (using heart valves).
• Regulates blood supply, adjusting its rate and force to meet metabolic needs.

Blood Vessels

• A closed network of tubes.
  • Arteries
  • Capillaries
  • Veins
• Arteries: distribute blood away from the heart.
  • Thick-walled
  • Elastic fibers
  • Circular smooth muscle
• Capillaries: microscopic vessels for nutrient and gas exchange.
  • Thin, one cell thick.
• Veins: drain blood toward the heart.
  • Thin-walled
  • Large irregular lumen
  • Have valves to prevent backflow

Blood Vessel Structure

• Tunica intima (inner layer)
• Tunica media (middle layer)
• Tunica adventitia (outer layer)

Arteries

• Carry oxygenated blood away from the heart.
• Thickest blood vessels.
• High in oxygen.
• Accompanied by veins and nerves.
• Have a small lumen.
• No valves.
• Repeated branching.
• Types: Elastic, Muscular, Arterioles, terminal arterioles

Capillaries

• Smallest blood vessels, connecting arteries and veins.
• Where nutrient and gas exchange takes place.
• Continuous (skin, lung, smooth muscle)
• Fenestrated (pancreas, endocrine glands)
• Sinusoids (liver, spleen, bone marrow)

Veins

• Carry deoxygenated blood toward the heart.
• Thin-walled.
• Contain valves to prevent backflow.
• Factors responsible for venous return:
  • Muscle contraction
  • Negative intrathoracic pressure
  • Pulsation of arteries
  • Gravity
  • Valves

Anastomosis

• Communication between vessels.
  • End arteries: terminal branches do not anastomose with other arteries.
  • Collaterals: accompanying extra arteries to an area.
  • Arteriovenous anastomosis (skin of nose, lips, external ear)

End Arteries

• Central artery of retina.
• Arteries of spleen, liver, kidneys, metaphyses of long bones.
• Central branches of cerebral cortex

Circulation

• Coronary circulation: blood flow within the heart.
• Pulmonary circulation: blood flow between the heart and lungs.
• Systemic circulation: blood flow between the heart and body cells.
• Fetal circulation (details not provided)

Systemic and Pulmonary Circulation

• Pulmonary circulation: blood flow between heart and lungs.
• Systemic circulation: blood flow between heart and body cells.

Portal Circulation

• Blood flow between two capillary beds before draining into systemic veins (e.g., liver).

Coronary Circulation: Arterial Supply

• Arteries that supply blood to the heart muscle.

This quiz covers the essential components and functions of the human cardiovascular system, including the heart, blood, and blood vessels. Understand how this vital system transports nutrients, facilitates gas exchange, and supports immune function. Perfect for students looking to familiarize themselves with basic cardiovascular concepts.