Transport in Animals 🚚

Animals require transport systems for various functions:

• Transport of nutrients: Dissolved food substances are transported from the intestines to tissue cells. 🍽️
• Oxygen transport: Oxygen moves from the lungs to tissue cells. 🌬️
• Hormone delivery: Hormones travel from endocrine (ductless) glands to target organs. 💊
• Waste removal: Metabolic wastes are carried from tissue cells to excretory organs. 🚮

The Blood Circulatory System

The blood circulatory system consists of:

• The Heart ❤️
• Blood Vessels 🩸
• The Blood 💧

The Heart

The heart is a muscular organ that pumps blood throughout the body. It has two sides:

• Right Side: Pumps deoxygenated blood to the lungs. 🌬️
• Left Side: Pumps oxygenated blood to the rest of the body. ❤️

Major Blood Vessels of the Heart:

• Veins:
• Vena Cava: Carries blood from the body to the right atrium. 🩸
• Pulmonary Vein: Carries oxygenated blood from the lungs to the left atrium. 🌬️
• Arteries:
• Aorta: Carries oxygenated blood from the left ventricle to the body. ❤️
• Pulmonary Artery: Carries deoxygenated blood from the right ventricle to the lungs. 🌬️
• Coronary Arteries: Branch from the aorta to supply the heart muscle. ❤️

Heart Function and the Cardiac Cycle

The cardiac muscle is myogenic (self-stimulating), meaning it can initiate contractions on its own. 💪

Double Circulation in Mammals

Mammals have a double circulation system with:

• Pulmonary Circulation: Blood flows from the right ventricle to the lungs and returns to the left atrium. 🌬️
• Systemic Circulation: Blood flows from the left ventricle to the body and returns to the right atrium. ❤️

Heart Rate and Pulse Rate

• Heart Rate: The number of heartbeats per minute. A normal adult’s resting heart rate is around 72 beats per minute. ❤️
• Pulse Rate: The number of pulses per minute, indirectly reflecting heart rate. 💓

Coronary Heart Disease (CHD)

Coronary Heart Disease involves the blockage of coronary arteries due to fatty deposits, which can lead to:

• Atheroma: Fatty material buildup in artery walls. 🩸
• Sclerosis: Hardening of artery walls due to fat deposits. ⚠️
• Thrombosis: Artery blockage by clots. 🩹
• Angina: Chest pain from restricted blood flow. 💔

Risk Factors for CHD

• High-fat diet: Converts to cholesterol, blocking arteries. 🍔
• Smoking: Nicotine promotes cholesterol accumulation. 🚬
• Emotional stress: Increases adrenaline, promoting cholesterol buildup. 😟
• Lack of exercise: Reduces cardiovascular health. 🏃‍♂️

Prevention of CHD

• Limit fatty foods 🍽️
• Avoid smoking 🚭
• Manage stress effectively 🧘‍♂️
• Exercise regularly to maintain heart health 🏋️‍♂️

The Circulatory System

The circulatory system consists of blood vessels, blood, and the lymphatic system. It transports nutrients 🍏, oxygen 🌬️, waste products 🚮, and hormones 💊 throughout the body, playing a crucial role in maintaining homeostasis.

1. Arteries

• High blood pressure and thick walls with narrow lumens to withstand the force of blood from the heart. ❤️
• No valves, as the heart’s pressure keeps blood flowing in one direction.
• Primarily carry oxygenated blood, except the pulmonary artery, which carries deoxygenated blood. 🌬️
• Located deep beneath the skin.

2. Veins

• Low blood pressure and thin walls with wide lumens.
• Presence of valves to prevent backflow. 🔄
• Generally carry deoxygenated blood, except the pulmonary vein, which carries oxygenated blood. 🌬️
• Located closer to the skin surface.

3. Capillaries 🌐

• Very thin walls (one cell thick) to allow efficient exchange of materials between blood and tissue cells. 🩸
• Direct contact with tissues, forming networks known as capillary beds. 🛏️
• Role in forming tissue fluid, aiding in temperature regulation 🌡️ and facilitating material exchange. 🔄

1. Red Blood Cells (Erythrocytes) 🩸

Responsible for oxygen transport, red blood cells are:

• Biconcave, increasing their surface area for gas exchange. 🌬️
• Packed with hemoglobin, binding oxygen in areas of high concentration and releasing it in areas of low concentration. 💨
• Produced in bone marrow and have a lifespan of about 120 days. ⏳

2. White Blood Cells (Leukocytes) 🦠

Defend the body against infection, produced in the bone marrow and lymphoid organs:

• Phagocytes: Engulf and digest foreign bodies using amoeboid movement. 🔍
• Lymphocytes: Produce antibodies and antitoxins to neutralize pathogens. 💉

3. Platelets (Thrombocytes) 🩹

Involved in blood clotting, releasing enzymes like thromboplastin to initiate clot formation. 🩸

4. Blood Plasma 💧

Plasma is the liquid part of blood, containing:

• Dissolved food, wastes, and hormones. 🍽️
• Plasma proteins maintaining blood pH, osmotic balance, and viscosity. ⚖️

• Group A: Antigen A with Anti-B antibodies. 🅰️
• Group B: Antigen B with Anti-A antibodies. 🅱️
• Group AB: Both antigens, no antibodies, known as the "universal recipient." 🆎
• Group O: No antigens with both antibodies, known as the "universal donor." ⭕

The Rhesus (Rh) factor is another blood antigen. Rh+ individuals have the antigen, while Rh- individuals lack it. Rhesus incompatibility can cause pregnancy complications if an Rh- mother carries an Rh+ fetus. 🤰

• Sickle Cell Anemia: 🩸 Abnormal hemoglobin causes sickle-shaped red blood cells, reducing oxygen transport. 🌬️
• Hemophilia: 🩹 An inherited disorder where blood does not clot properly due to a lack of specific clotting factors.
• Leukemia: 🦠 A cancer of white blood cells leading to an overproduction of immature white blood cells.

• Lymphatic Vessels: 🚤 Carry lymph, containing valves to prevent backflow.
• Lymph Nodes and Organs: 🏥 Filter foreign particles, produce and store lymphocytes, becoming active during infections. 🦠

The lymphatic system drains excess tissue fluid back into the blood, adds lymphocytes for immune defense 🛡️, and absorbs fatty acids from the digestive system. 🍽️

The circulatory system is essential for maintaining the body's internal environment and ensuring that every cell receives the oxygen 🌬️ and nutrients 🍏 it needs. It also plays a vital role in immune response 🛡️ and waste removal 🚮, supporting overall health and homeostasis.

• Transportation: 🚚 Delivers oxygen 🌬️, nutrients 🍏, and hormones 💊 to cells while removing waste products. 🚮
• Regulation: ⚖️ Helps regulate body temperature 🌡️ and pH balance.
• Protection: 🛡️ Defends the body against infections through white blood cells and antibodies in the lymphatic system. 🦠

A typical capillary bed illustrates how oxygen 🌬️, nutrients 🍏, carbon dioxide 💨, and waste products 🚮 are exchanged between blood and tissues. Capillaries connect arteries and veins, allowing the passage of materials between blood and body tissues. This exchange occurs due to the thin, one-cell-thick walls of capillaries. 🩸