Digestive System
What is the main function of the digestive system?
→ Break down food and absorb nutrients
What gas do humans inhale for respiration?
Oxygen
What is the main function of the circulatory system?
→ Transport substances (oxygen, nutrients, waste)
What is the main function of the nervous system?
→ Control and coordination
What is homeostasis?
→ Maintaining stable internal conditions
Where does most nutrient absorption occur?
→ Small intestine
Where does gas exchange occur in the lungs?
Alveoli
What are the three main types of blood vessels?
→ Arteries, veins, capillaries
What is the role of the brain?
→ Processes information and controls responses
Which two systems work together during exercise?
→ Respiratory + circulatory
What is the role of enzymes in digestion?
→ To chemically break down food into smaller molecules
What is the role of the diaphragm during inhalation?
→ Contracts and moves down, increasing chest volume
What is the function of red blood cells?
Carry oxygen
What is a stimulus?
→ A change in the environment
Why does breathing rate increase during exercise?
→ More oxygen needed, more CO₂ removed
Why is the small intestine adapted for absorption? (Give one feature)
→ Large surface area (villi/microvilli), thin walls, rich blood supply
How are alveoli adapted for efficient gas exchange?
→ Large surface area, thin walls, moist surface, rich blood supply
How do veins differ from arteries?
→ Thinner walls, lower pressure, valves to prevent backflow
Difference between nervous and endocrine systems?
→ Nervous = fast, electrical; endocrine = slow, hormonal
Explain how two systems work together to digest and transport nutrients.
→ Digestive breaks down food; circulatory transports nutrients
Explain why both mechanical and chemical digestion are needed.
→ Mechanical increases surface area; chemical breaks molecules into absorbable forms
Explain how structure of the lungs maximises diffusion.
→ Thin membranes + large SA + concentration gradient + blood flow
Explain how the circulatory system supports other body systems.
→ Transports oxygen/nutrients to cells and removes wastes
Explain how the body responds to a hot environment.
→ Sweating, vasodilation, nervous/endocrine signals maintain temp
Describe how multiple body systems maintain homeostasis during exercise.
→ Respiratory ↑ oxygen, circulatory transports, nervous regulates, sweating cools