Transport Systems in Animals

Study Notes

Conducting systems connect isolated cell groups necessary for transporting materials.
Diffusion, osmosis, or active transport are inefficient for large quantities of materials.

Oxygen is essential for cellular respiration.
Excretory products include carbon dioxide, urea, and water.
Digested food substances transported include amino acids, glucose, fatty acids, and glycerol.
Hormones and antibodies are also vital for bodily functions.

Open Circulatory System:
- Blood (hemolymph) is not confined to blood vessels, e.g., arthropods and mollusks.
- Hemolymph pumps into a hemocoel allowing nutrient and gas exchange.
- Requires less energy but less efficiently delivers blood to metabolically active tissues.
Closed Circulatory System:
- Blood is contained in vessels, allowing for efficient transport (e.g., annelids, cephalopods, vertebrates).
- Features a heart that pumps blood through a network of vessels in a unidirectional flow.

Composed of red blood cells, white blood cells, platelets, and plasma.
Red Blood Cells (Erythrocytes): Contain hemoglobin for oxygen transport.
White Blood Cells (Leucocytes): Key players in the immune response against pathogens.
Platelets (Thrombocytes): Essential for blood clotting.
Plasma: Liquid component carrying water, proteins, salts, lipids, and glucose.

Microscopic vessels for gas, nutrient, and waste exchange.
Narrow enough for single red blood cell passage; thin walls facilitate efficient exchange.
Capillaries connect to venules (small veins).

Muscular organ that pumps blood, varying structure between organisms (e.g., two-chambered in fish, four-chambered in mammals).
Comprised of four chambers:
- Auricles (atria): Receive blood.
- Ventricles: Pump blood out.
Valves prevent backflow; separation of oxygenated and deoxygenated blood is crucial in mammals.

Single Circulation: Characteristic of fish; blood passes through the heart once per circuit.
Double Circulation: Found in amphibians, reptiles, birds, and mammals; blood passes through the heart twice, enhancing oxygen delivery.

Nervous Control: Autonomic nervous system regulates heart rate and blood vessel constriction.
Endocrine Control: Hormones like adrenaline affect heart rate and blood volume.
Exercise Response: Increases heart rate and directs blood flow to muscles over digestive organs.

Source-to-Sink Theory: Sugars produced in leaves (source) are sent to growth/storage areas (sink).
Pressure-Flow Hypothesis: Sugars actively loaded into sieve tubes create pressure that pushes the solution through phloem.

Xylem: Transports water/minerals in a unidirectional manner; composed of dead cells.
Phloem: Transports sugars/nutrients bidirectionally; composed of living cells.

Challenges include transporting materials over distances and maintaining water balance.
Adaptations in Xerophytes (e.g., thick cuticles) and Hydrophytes (e.g., air spaces) enhance survival in varying environments.