IP2 Green Science Chapter 6 Transport in Humans (Biology) - Key Terms

Vocabulary flashcards covering key terms and concepts from the lecture notes on the transport system in humans.

Circulatory system

The organ system that transports nutrients, oxygen, and wastes through blood to and from all body cells; includes the heart, blood, and blood vessels.

Heart

The muscular pump that drives blood around the body as part of the circulatory system.

Blood

A fluid tissue that carries cells suspended in plasma and acts as the transport medium in the circulatory system.

Blood vessels

The network (arteries, veins, capillaries) that transport blood; arteries carry blood away from the heart, veins carry it toward the heart, capillaries enable exchange with tissues.

Double circulation

Blood passes through the heart twice per full circuit, consisting of pulmonary and systemic circulations.

Pulmonary circulation

Circulation between the heart and lungs; carries blood to the lungs for gas exchange and back to the heart; operates under relatively low pressure.

Systemic circulation

Circulation between the heart and the rest of the body; delivers oxygenated blood to tissues and returns deoxygenated blood to the heart; operates under higher pressure.

Plasma

The pale yellow fluid of blood (mostly water, about 90%) that carries dissolved substances such as nutrients, CO2, and hormones.

Red blood cells (RBCs)

Cells that transport oxygen; biconcave shape increases surface area; contain haemoglobin; lack a nucleus to maximise oxygen carrying; lifespan ~120 days.

Haemoglobin

Iron-containing pigment in RBCs that binds to oxygen to form oxyhaemoglobin; gives blood its red color; Fe2+ binds O2 reversibly.

Oxyhaemoglobin

Haemoglobin bound to oxygen; bright red color; forms in the lungs during oxygen uptake.

Carbon monoxide poisoning

Toxic effect from CO binding irreversibly to haemoglobin’s Fe2+, reducing oxygen transport.

White blood cells (WBCs)

Immune cells that protect the body; larger than RBCs; some perform phagocytosis, others produce antibodies; have a nucleus.

Phagocytosis

Process by which WBCs engulf and digest foreign bodies such as bacteria.

Antibodies

Proteins produced by WBCs that defend against infections by binding to pathogens.

Platelets

Small fragments of bone marrow cells (2–4 μm) that form sticky plugs to clot wounds and seal breaches.

Blood pH range

Normal blood pH is 7.35–7.45; outside this range can be fatal; blood acts as a buffer system.

Blood buffer system

Mechanisms in blood that resist changes in pH, maintaining pH around 7.35–7.45.

Temperature regulation by blood

Blood helps maintain body temperature around 36.4–37.6°C because water has high heat capacity.

Arteries

Blood vessels that carry blood away from the heart; high pressure; thick muscular walls; smaller lumen.

Veins

Blood vessels that carry blood toward the heart; lower pressure; valves to prevent backflow; larger lumen.

Capillaries

Microscopic vessels one cell thick that connect arteries to veins; enable rapid diffusion between blood and tissues.

Arterioles

Small arteries that branch from arteries and lead to capillaries; part of microcirculation.

Venules

Small veins formed when capillaries unite; drain blood from capillaries into veins.

Diffusion in capillaries

Oxygen and nutrients diffuse from blood to tissues; carbon dioxide and wastes diffuse from tissues to blood, driven by concentration gradients.

Complex tissue

Blood is a complex tissue because it contains multiple cell types (RBCs, WBCs, platelets) suspended in plasma.

Blood as a mixture

Blood fractionation shows distinct components (plasma, RBCs, WBCs) indicating it is a mixture.

Gaseous exchange

Transfer of O2 and CO2 between lungs and blood (and between blood and tissues).