🩸 TRANSPORT IN ANIMALS
1️⃣Purpose of Transport
• All multicellular animals need a transport system to move oxygen,
nutrients, and wastes between body cells and the environment.
• Small organisms (like amoeba) use diffusion, but large animals need a
circulatory system because diffusion is too slow over long distances.
⸻
2️⃣
Types of Circulatory Systems
(a) Open Circulatory System
• Found in insects and other small invertebrates.
• Blood (called haemolymph) flows freely in body cavities and directly
bathes organs.
• No capillaries; blood not always enclosed in vessels.
• Pressure is low and circulation is slow.
(b) Closed Circulatory System
• Found in humans and vertebrates.
• Blood flows within vessels (arteries, veins, capillaries).
• Maintains high pressure → efficient transport of oxygen and nutrients.
⸻
3️⃣The Human Circulatory System
• Made of heart, blood vessels, and blood.
• Double circulatory system → blood passes through the heart twice in one
complete circuit:
1. Pulmonary circulation – from right ventricle → lungs → left atrium
(oxygenation of blood)
2. Systemic circulation – from left ventricle → body → right atrium
(delivers oxygen to cells)
Advantages:
• Maintains high pressure.
• Oxygenated and deoxygenated blood kept separate → efficient gas
exchange.
⸻
4️⃣
The Heart ❤️
Structure
• Muscular, cone-shaped organ in the thoracic cavity between the lungs.
• Surrounded by the pericardium (protective membrane with fluid).
• Has four chambers:
• Right atrium – receives deoxygenated blood from body via vena cava.
• Right ventricle – pumps it to lungs via pulmonary artery.
• Left atrium – receives oxygenated blood from lungs via pulmonary vein.
• Left ventricle – pumps oxygenated blood to body via aorta.
• The left ventricle wall is thicker → pumps blood under higher pressure
to the whole body.
Valves
• Atrioventricular (AV) valves – between atria and ventricles:
, • Right: tricuspid valve
• Left: bicuspid (mitral) valve
• Semilunar valves – at exits of the pulmonary artery and aorta.
→ Prevent backflow of blood.
⸻
5️⃣
Flow of Blood Through the Heart
1️⃣
Deoxygenated blood → vena cava → right atrium
2️⃣
Through tricuspid valve → right ventricle
3️⃣
Through pulmonary semilunar valve → pulmonary artery → lungs
4️⃣
Gas exchange occurs in alveoli → blood becomes oxygenated
5️⃣
Oxygenated blood → pulmonary vein → left atrium
6️⃣
Through bicuspid valve → left ventricle
7️⃣
Through aortic semilunar valve → aorta → body
⸻
6️⃣
The Cardiac Cycle (heartbeat)
• Systole = contraction, Diastole = relaxation.
Phase Event
Atrial systole Atria contract → blood pushed into ventricles.
Ventricular systole Ventricles contract → blood forced into aorta & pulmonary
artery.
General diastole Heart relaxes → blood flows into atria again.
• The “lub-dub” sound: closing of AV valves (lub) and semilunar valves
(dub).
⸻
7️⃣
Blood Vessels
Vessel Function Characteristics
Arteries Carry blood away from heart (usually oxygenated). Thick, elastic,
muscular walls; small lumen; high pressure.
Veins Carry blood to the heart (usually deoxygenated). Thin walls; large lumen;
valves prevent backflow; low pressure.
Capillaries Connect arteries and veins; site of exchange. One-cell thick; allow
diffusion of gases and nutrients.
⸻
8️⃣
Blood as a Tissue
Composition
• Plasma – yellowish fluid (≈55% of blood). Carries nutrients, hormones,
waste, CO₂, etc.
• Red Blood Cells (Erythrocytes) – biconcave, no nucleus, contain
haemoglobin for oxygen transport.
• White Blood Cells (Leucocytes) – defend body against infection.
• Phagocytes → engulf pathogens.
• Lymphocytes → produce antibodies.
• Platelets (Thrombocytes) – small cell fragments that help clot blood.
⸻
,9️⃣
The Lymphatic System
Functions
• Collects excess tissue fluid (lymph) and returns it to the bloodstream.
• Transports fats absorbed from intestines.
• Defends body against infection via lymph nodes (produce lymphocytes).
Components
• Lymph – tissue fluid containing white blood cells and proteins.
• Lymph vessels – carry lymph to veins near heart.
• Lymph nodes – filter out bacteria and produce antibodies.
⸻
🔟 Blood Pressure
• The pressure exerted by circulating blood on artery walls.
• Systolic pressure – during contraction (normal ≈ 120 mm Hg).
• Diastolic pressure – during relaxation (normal ≈ 80 mm Hg).
• Measured with a sphygmomanometer.
Importance
• Keeps blood flowing throughout body.
• High or low BP can cause health issues (stroke, heart disease, etc.).
⸻
11️⃣
Blood Disorders and Circulatory Diseases
Disease Cause Effect
Anaemia Lack of haemoglobin or iron Fatigue, pale skin, weakness
Leukaemia Uncontrolled white blood cell production Affects oxygen transport,
weak immunity
Hypertension High blood pressure Damage to arteries, heart strain
Stroke Blockage or burst in brain blood vessel Brain damage, paralysis
Coronary heart disease (CHD) Fatty deposits in coronary arteries Reduced blood flow
to heart, chest pain (angina), heart attack
Prevention
• Healthy diet (low in fats and salt)
• Regular exercise
• Avoid smoking and stress
• Maintain healthy weight and blood pressure
⸻
⸻
🩸 GRADE 11 LIFE SCIENCES
TRANSPORT IN ANIMALS (HUMANS)
⸻
🌍 1. Why Animals Need a Transport System
• Every cell in an organism needs oxygen, nutrients, water, and hormones,
and must remove carbon dioxide and wastes.
• In unicellular organisms like amoeba, these materials move by diffusion
directly across the cell membrane — because all parts of the cell are close to the
, environment.
• In multicellular organisms (like humans), diffusion alone is too slow
because:
• There are many cells far from the body surface.
• The surface area-to-volume ratio is smaller.
• Metabolic activities are higher → more oxygen and nutrients needed.
• ➡️ Therefore, humans need a transport system (circulatory system) to
carry materials to and from all body cells efficiently.
⸻
🧩 2. Types of Circulatory Systems
(a) 🪲 Open Circulatory System
• Found in insects and some invertebrates.
• Blood (called haemolymph) is not always enclosed in vessels.
• It flows through body cavities (haemocoel) and directly bathes the
organs.
• There is no distinction between blood and tissue fluid.
• Circulation is slow and under low pressure.
• Example: Grasshopper — heart pumps haemolymph into body cavities; it
slowly returns to heart openings (ostia).
(b) 🐸 Closed Circulatory System
• Found in vertebrates (fish, amphibians, reptiles, birds, mammals).
• Blood is always enclosed in vessels (arteries, veins, capillaries).
• Blood flows quickly under high pressure.
• Substances move between blood and tissues through capillary walls.
• More efficient → allows higher metabolic rate and body temperature
control.
⸻
♻️
3. Types of Blood Circulation in Humans
🫁 Pulmonary Circulation
• Carries deoxygenated blood from right ventricle → lungs.
• In lungs, blood releases CO₂ and picks up O₂.
• Oxygenated blood returns to left atrium.
❤️
Systemic Circulation
• Carries oxygenated blood from left ventricle → body tissues.
• Body cells use O₂ and produce CO₂.
• Deoxygenated blood returns to right atrium.
🌀 Double Circulation:
Blood passes through the heart twice in one complete circuit (body → heart → lungs
→ heart → body).
➡️ Maintains high pressure and keeps oxygenated & deoxygenated blood separate,
improving efficiency.
⸻
💓 4. The Human Heart
🫀 Structure
• Location: In the thoracic cavity (chest), between lungs, tilted
slightly left.
• Size: About the size of your fist.
1️⃣Purpose of Transport
• All multicellular animals need a transport system to move oxygen,
nutrients, and wastes between body cells and the environment.
• Small organisms (like amoeba) use diffusion, but large animals need a
circulatory system because diffusion is too slow over long distances.
⸻
2️⃣
Types of Circulatory Systems
(a) Open Circulatory System
• Found in insects and other small invertebrates.
• Blood (called haemolymph) flows freely in body cavities and directly
bathes organs.
• No capillaries; blood not always enclosed in vessels.
• Pressure is low and circulation is slow.
(b) Closed Circulatory System
• Found in humans and vertebrates.
• Blood flows within vessels (arteries, veins, capillaries).
• Maintains high pressure → efficient transport of oxygen and nutrients.
⸻
3️⃣The Human Circulatory System
• Made of heart, blood vessels, and blood.
• Double circulatory system → blood passes through the heart twice in one
complete circuit:
1. Pulmonary circulation – from right ventricle → lungs → left atrium
(oxygenation of blood)
2. Systemic circulation – from left ventricle → body → right atrium
(delivers oxygen to cells)
Advantages:
• Maintains high pressure.
• Oxygenated and deoxygenated blood kept separate → efficient gas
exchange.
⸻
4️⃣
The Heart ❤️
Structure
• Muscular, cone-shaped organ in the thoracic cavity between the lungs.
• Surrounded by the pericardium (protective membrane with fluid).
• Has four chambers:
• Right atrium – receives deoxygenated blood from body via vena cava.
• Right ventricle – pumps it to lungs via pulmonary artery.
• Left atrium – receives oxygenated blood from lungs via pulmonary vein.
• Left ventricle – pumps oxygenated blood to body via aorta.
• The left ventricle wall is thicker → pumps blood under higher pressure
to the whole body.
Valves
• Atrioventricular (AV) valves – between atria and ventricles:
, • Right: tricuspid valve
• Left: bicuspid (mitral) valve
• Semilunar valves – at exits of the pulmonary artery and aorta.
→ Prevent backflow of blood.
⸻
5️⃣
Flow of Blood Through the Heart
1️⃣
Deoxygenated blood → vena cava → right atrium
2️⃣
Through tricuspid valve → right ventricle
3️⃣
Through pulmonary semilunar valve → pulmonary artery → lungs
4️⃣
Gas exchange occurs in alveoli → blood becomes oxygenated
5️⃣
Oxygenated blood → pulmonary vein → left atrium
6️⃣
Through bicuspid valve → left ventricle
7️⃣
Through aortic semilunar valve → aorta → body
⸻
6️⃣
The Cardiac Cycle (heartbeat)
• Systole = contraction, Diastole = relaxation.
Phase Event
Atrial systole Atria contract → blood pushed into ventricles.
Ventricular systole Ventricles contract → blood forced into aorta & pulmonary
artery.
General diastole Heart relaxes → blood flows into atria again.
• The “lub-dub” sound: closing of AV valves (lub) and semilunar valves
(dub).
⸻
7️⃣
Blood Vessels
Vessel Function Characteristics
Arteries Carry blood away from heart (usually oxygenated). Thick, elastic,
muscular walls; small lumen; high pressure.
Veins Carry blood to the heart (usually deoxygenated). Thin walls; large lumen;
valves prevent backflow; low pressure.
Capillaries Connect arteries and veins; site of exchange. One-cell thick; allow
diffusion of gases and nutrients.
⸻
8️⃣
Blood as a Tissue
Composition
• Plasma – yellowish fluid (≈55% of blood). Carries nutrients, hormones,
waste, CO₂, etc.
• Red Blood Cells (Erythrocytes) – biconcave, no nucleus, contain
haemoglobin for oxygen transport.
• White Blood Cells (Leucocytes) – defend body against infection.
• Phagocytes → engulf pathogens.
• Lymphocytes → produce antibodies.
• Platelets (Thrombocytes) – small cell fragments that help clot blood.
⸻
,9️⃣
The Lymphatic System
Functions
• Collects excess tissue fluid (lymph) and returns it to the bloodstream.
• Transports fats absorbed from intestines.
• Defends body against infection via lymph nodes (produce lymphocytes).
Components
• Lymph – tissue fluid containing white blood cells and proteins.
• Lymph vessels – carry lymph to veins near heart.
• Lymph nodes – filter out bacteria and produce antibodies.
⸻
🔟 Blood Pressure
• The pressure exerted by circulating blood on artery walls.
• Systolic pressure – during contraction (normal ≈ 120 mm Hg).
• Diastolic pressure – during relaxation (normal ≈ 80 mm Hg).
• Measured with a sphygmomanometer.
Importance
• Keeps blood flowing throughout body.
• High or low BP can cause health issues (stroke, heart disease, etc.).
⸻
11️⃣
Blood Disorders and Circulatory Diseases
Disease Cause Effect
Anaemia Lack of haemoglobin or iron Fatigue, pale skin, weakness
Leukaemia Uncontrolled white blood cell production Affects oxygen transport,
weak immunity
Hypertension High blood pressure Damage to arteries, heart strain
Stroke Blockage or burst in brain blood vessel Brain damage, paralysis
Coronary heart disease (CHD) Fatty deposits in coronary arteries Reduced blood flow
to heart, chest pain (angina), heart attack
Prevention
• Healthy diet (low in fats and salt)
• Regular exercise
• Avoid smoking and stress
• Maintain healthy weight and blood pressure
⸻
⸻
🩸 GRADE 11 LIFE SCIENCES
TRANSPORT IN ANIMALS (HUMANS)
⸻
🌍 1. Why Animals Need a Transport System
• Every cell in an organism needs oxygen, nutrients, water, and hormones,
and must remove carbon dioxide and wastes.
• In unicellular organisms like amoeba, these materials move by diffusion
directly across the cell membrane — because all parts of the cell are close to the
, environment.
• In multicellular organisms (like humans), diffusion alone is too slow
because:
• There are many cells far from the body surface.
• The surface area-to-volume ratio is smaller.
• Metabolic activities are higher → more oxygen and nutrients needed.
• ➡️ Therefore, humans need a transport system (circulatory system) to
carry materials to and from all body cells efficiently.
⸻
🧩 2. Types of Circulatory Systems
(a) 🪲 Open Circulatory System
• Found in insects and some invertebrates.
• Blood (called haemolymph) is not always enclosed in vessels.
• It flows through body cavities (haemocoel) and directly bathes the
organs.
• There is no distinction between blood and tissue fluid.
• Circulation is slow and under low pressure.
• Example: Grasshopper — heart pumps haemolymph into body cavities; it
slowly returns to heart openings (ostia).
(b) 🐸 Closed Circulatory System
• Found in vertebrates (fish, amphibians, reptiles, birds, mammals).
• Blood is always enclosed in vessels (arteries, veins, capillaries).
• Blood flows quickly under high pressure.
• Substances move between blood and tissues through capillary walls.
• More efficient → allows higher metabolic rate and body temperature
control.
⸻
♻️
3. Types of Blood Circulation in Humans
🫁 Pulmonary Circulation
• Carries deoxygenated blood from right ventricle → lungs.
• In lungs, blood releases CO₂ and picks up O₂.
• Oxygenated blood returns to left atrium.
❤️
Systemic Circulation
• Carries oxygenated blood from left ventricle → body tissues.
• Body cells use O₂ and produce CO₂.
• Deoxygenated blood returns to right atrium.
🌀 Double Circulation:
Blood passes through the heart twice in one complete circuit (body → heart → lungs
→ heart → body).
➡️ Maintains high pressure and keeps oxygenated & deoxygenated blood separate,
improving efficiency.
⸻
💓 4. The Human Heart
🫀 Structure
• Location: In the thoracic cavity (chest), between lungs, tilted
slightly left.
• Size: About the size of your fist.
