Transport in Animals and Human Heart Structure

Transport in Animals

• The circulatory system is the main transport system in humans.
• It's a network of tubes (blood vessels) powered by a pump (the heart) and valves maintaining one-way blood flow.
• Functions include transporting nutrients and oxygen to cells, removing waste and carbon dioxide from cells, and facilitating efficient gas exchange.
• Mammalian circulatory system is a closed, double circulation system.
  • Blood remains inside vessels.
  • Blood passes through the heart twice for a complete circuit of the body.

Single Circulation in Fish

• Fish have a two-chambered heart and single circulation.
• Blood flows through the heart only once during a complete circulation.
• Deoxygenated blood is pumped by the heart to the gills for oxygenation.
• Afterwards, the oxygenated blood travels to the rest of the body and back to the heart.

Human Heart Structure

• The heart diagram shows the different chambers, valves, and major blood vessels.
• Includes the atria (right and left), ventricles (right and left), vena cava (superior and inferior), pulmonary artery, pulmonary vein, aorta, and various valves (tricuspid, bicuspid/mitral, and semilunar). (Detailed diagram referenced)

Systemic and Pulmonary Circulation

• Systemic Circulation: The pathway of oxygen-rich blood from the left ventricle through the aorta to the body's tissues.
  • Deoxygenated blood returns through the vena cava to the right atrium.
• Pulmonary Circulation: The pathway of deoxygenated blood from the right ventricle to the lungs through the pulmonary artery, to become oxygenated.
  • The oxygenated blood returns from the lungs via the pulmonary veins to the left atrium.

Advantages of Double Circulation

• Keeps oxygenated and deoxygenated blood separate, preventing mixing.
• Provides efficient nutrient and oxygen delivery to body cells (like glucose, iron, calcium, protein, etc...).
• Lower pressure in the pulmonary artery prevents damage to lung capillaries.
• Allows high blood pressure to other body parts for efficient delivery in the systemic circulation pathway.
• Filtration in the kidneys is allowed because of the lower pressure.
• High rate of respiration and oxygen exchange.

Heart Actions (Systole/Diastole)

• Systole: Contraction of heart chambers (pumping phase).
• Diastole: Relaxation of heart chambers (filling phase).

Atria and Ventricle Wall Thickness

• Ventricle walls are thicker than atria walls.
• Ventricles have to generate higher pressure to pump blood to the lungs and body.
• Left ventricle (pumping to the whole body) is thicker than right ventricle (pumping to the lungs) because the pressure required is greater.
• Atria only pump blood into ventricles.

Blood Components and Function

• Plasma: Transports carbon dioxide, nutrients, urea, minerals, hormones, and heat energy.
• Red Blood Cells: Transport oxygen around the body, carrying oxygen in the form of oxyhaemoglobin.
• White Blood Cells: Defend the body against infection through phagocytosis and antibody production.
• Platelets: Essential for blood clotting.

Blood Clotting

• Injury to blood vessel lining triggers platelets to activate and bind to the wound site.
• Platelets release chemicals converting soluble fibrinogen into insoluble fibrin, forming the clot and preventing blood loss.
• The clot dries and forms a protective scab.

Phagocytosis

• Phagocytes engulf and digest pathogens, using their sensitive cell surface membrane to detect pathogens.
• Recognize chemical signals (antigens) released by pathogens.
• This is a non-specific immune response.

Lymphocytes (B cells) and Antibodies

• Lymphocytes create antibodies, proteins shaped to recognize and neutralize specific pathogens or toxins (antigens).
• Antibodies are specific to the antigen on the pathogen, ensuring a targeted immune response.

Arteries

• Narrow lumen which maintains high pressure.
• Thick walls to withstand high pressure.
• Corrugated inner lining (endothelium) for stretching during contraction.

Veins

• Wide lumen providing low resistance against blood flow.
• Smooth endothelium maintaining low-pressure flow.
• Valves to prevent backflow of blood.
• Contains elastic and muscle fibers

Capillaries

• Networks of thin-walled vessels facilitating efficient gas exchange and nutrient diffusion.
• Walls are only one cell thick (reducing diffusion distance).
• Walls are leaky (small gaps between epithelial cells) to allow water, ions, and nutrients to exchange with tissues.
• Small lumen to slow blood flow, brings red blood cells close to tissues for efficient exchange.

Important Arteries and Veins

• (List of veins & arteries by organ) Includes examples.

Coronary Heart Disease

• Coronary arteries supply blood to the heart muscle.
• Obstruction by plaque (fatty deposits) causes reduced blood flow.
• Partial blockage creates angina, while complete blockage leads to a heart attack.
• Risk factors include unhealthy diet, lack of exercise, smoking, genetics, stress, and age(males are more prone).

Preventing Coronary Heart Disease

• Recommendations include regular exercise, smoking cessation, balanced diet, weight management, salt reduction, stress reduction, and sometimes qualified medication use.

Monitoring Heart Activity

• Heart activity can be monitored by ECG (electrocardiogram), pulse rate, and listening for valve sounds.