Anatomy and Physiology for Health and Social Care - Cardiovascular System Blood, blood vessels and composition of blood

Unit 4: Anatomy and Physiology for Health and Social Care

Key Functions of the Cardiovascular System

• Transport of Materials:

  • Circulates oxygen, nutrients, and hormones throughout the body.

  • Removes waste products, including carbon dioxide.

• Support for Vital Organs:

  • Transports oxygen to working muscles.

  • Returns carbon dioxide waste to lungs for expiration.

• Waste Management:

  • Carries waste products from tissues to excretory organs.

• Immune Function:

  • Protects against disease and infection (role of white blood cells).

• Clotting Mechanism:

  • Stops bleeding after injury (function of platelets).

• Thermoregulation:

  • Regulates body temperature by managing blood flow to skin surfaces.

Composition of Blood

1. Plasma

   • Description: Clear yellowish liquid, makes up 55% of blood.

   • Function: Carries blood cells, nutrients, and proteins.

2. Erythrocytes (Red Blood Cells)

   • Description: Contain hemoglobin, red in color, thin disc-like shape.

   • Function: Transport oxygen by forming oxyhemoglobin.

3. Leucocytes (White Blood Cells)

   • Types and Functions:

     • Lymphocytes: Part of immune response, B-cells and T-cells.

     • Neutrophils: First responders to infections.

     • Monocytes: Largest WBC, involved in infection clearance.

4. Platelets

   • Description: Fragments of larger cells.

   • Function: Involved in blood clotting.

Functions of Blood

1. Transporting Nutrients and Gases:

   • Blood carries oxygen and carbon dioxide between tissues and lungs.

   • Red blood cells structure aids in oxygen transportation (biconcave shape increases surface area).

2. Temperature Regulation:

   • Maintains body temperature at approximately 37^{ ext{°C}} by vasodilation and vasoconstriction.

3. Exchange of Materials:

   • Nutrients pass from blood into cells through capillary walls (1 cell thick).

   • Excess fluid drained into lymph vessels.

4. Preventing Infection:

   • White blood cells identify and destroy pathogens.

   • Antibodies produced by lymphocytes target specific invaders.

5. Blood Clotting Mechanism:

   • Platelets initiate coagulation process to prevent excessive blood loss.

   • Vital to prevent infection and organ damage due to open wounds.

Types, Structure, and Function of Blood Vessels

1. Arteries

   • Carry oxygenated blood away from the heart (except pulmonary arteries).

   • Thick muscular elastic walls to withstand high pressure.

   • Largest artery: the aorta.

2. Veins

   • Carry deoxygenated blood towards the heart (except pulmonary veins).

   • Thinner walls and lower blood pressure.

   • Contain valves to prevent backflow.

3. Capillaries

   • Walls are one cell thick, allowing for exchange of materials.

   • Connect arteries and veins, facilitating nutrient and waste transfer.

Comparison of Blood Vessels