Human Transport System Flashcards

Blood Composition

  • Blood consists of plasma and cells (red blood cells, white blood cells, and platelets).

Plasma

  • Liquid component of blood, mainly water with dissolved substances.

  • Composition maintained by the liver and kidney.

  • Contains plasma proteins, amino acids, glucose, lipids, vitamins, hormones, mineral ions, and urea.

Red Blood Cells (Erythrocytes)

  • Lack a nucleus; numerous; biconcave shape for increased surface area.

  • Formed in bone marrow.

  • Lifespan of 100 days, destroyed in the liver and spleen.

  • Contain haemoglobin (red pigment).

  • Blood with oxygen is called oxygenated blood; without oxygen, deoxygenated blood.

White Blood Cells (Leukocytes)

  • Two types: lymphocytes and phagocytes.

Lymphocytes

  • Large, bean-shaped nucleus.

  • Produce antibodies that bind with bacteria.

  • Neutralize poisonous proteins (toxins).

Phagocytes

  • Irregular shape and lobed nucleus.

  • Squeeze through capillaries to engulf bacteria (phagocytosis).

  • Gather at injury/infection sites, causing inflammation (redness, swelling, pain).

Platelets (Thrombocytes)

  • Cell fragments without a nucleus.

  • Less numerous than RBCs.

  • Formed in bone marrow.

  • Responsible for blood clotting.

Blood Functions

Transport

  • Oxygen from lungs to tissues, carbon dioxide from tissues to lungs.

  • Dissolved food substances from intestines to the body.

  • Urea from liver to kidneys.

  • Hormones from glands to target sites.

Homeostasis

  • Maintains equilibrium in internal environment.

  • Controls water in tissues, maintains constant pH and chemical levels.

Defence

  • White blood cells (phagocytes) engulf and digest bacteria.

Tissue Fluid

  • Watery liquid bathing cells, facilitating material exchange.

  • Formed from blood plasma.

Blood Vessels

  • Arteries, veins, capillaries, arterioles, venules.

Human Circulatory System

  • Double circulation: pulmonary (lung) and systemic (body) circuits.

  • Unidirectional blood flow.

The Human Heart

  • Made of cardiac muscle (myogenic).

  • Nerves and hormones (e.g., adrenaline) can alter heart rate.

Health Problems

  • Atherosclerosis, kidney damage can lead to hypertension.

  • High cholesterol can obstruct blood flow.

Angina

  • Cramps in cardiac muscle due to reduced blood flow; lactic acid build-up.

Heart Attack

  • Cardiac muscle stops contracting due to insufficient blood supply.

  • Other factors: smoking, diabetes, lack of exercise, obesity; some conditions are inherited.