EXCRETORY SYSTEM
Q: What is the main purpose of the excretory system?
A: To remove waste products from the body, such as urea, excess water and salts.
Q: What is the main purpose of the respiratory system?
A: To take in oxygen and remove carbon dioxide from the body (gas exchange).
Q: What is the main purpose of the digestive system?
A: To break down food into smaller nutrients that the body can absorb and use for energy and growth and remove wastes
Q: What is the main purpose of the circulatory system?
A: To transport oxygen, nutrients, wastes and other substances around the body in the blood.
Q: What is the basic unit of life, found in all living things?
A: The cell.
Q: What are the two bean-shaped organs that filter waste from the blood to form urine?
A: The kidneys.
Q: What is the large muscle below the lungs that helps you breathe in and out?
A: The diaphragm.
Q: What is the muscular tube that carries food from your throat to your stomach?
A: The oesophagus (esophagus).
Q: What is the muscular organ that pumps blood around the body?
A: The heart.
Q: List the levels of organisation in the human body, from simplest to most complex.
A: Cell → Tissue → Organ → Organ system → Organism.
Q: What tube carries urine from each kidney down to the bladder?
A: The ureter.
Q: What are the tiny air sacs in the lungs where gas exchange happens?
A: Alveoli.
Q: Which organ produces bile to help digest fats?
A: The liver.
Q: What is the difference between arteries and veins?
A: Arteries carry blood away from the heart; veins carry blood back to the heart.
Q: What is cellular respiration?
A: The process where cells release energy from glucose using oxygen, producing carbon dioxide and water as waste products.
Q: What organ stores urine until it leaves the body, and what tube carries it out?
A: The bladder stores urine; the urethra carries it out of the body.
Q: Put these in order to show the path air takes when entering the respiratory system: Bronchi, Trachea, Alveoli, Nose/mouth, Bronchioles.
A: Nose/mouth → Trachea → Bronchi → Bronchioles → Alveoli.
Q: Put these organs in the correct order that food passes through: Stomach, Mouth, Small intestine, Large intestine, Oesophagus.
A: Mouth → Oesophagus → Stomach → Small intestine → Large intestine.
Q: What are the tiny blood vessels where oxygen, nutrients and wastes are exchanged between the blood and body cells?
A: Capillaries.
Q: Name the organelle inside a cell where most cellular respiration takes place.
A: The mitochondria (mitochondrion).
Q: Put these in order to show the path urine takes, from where it's made to where it exits the body: Bladder, Kidney, Urethra, Ureter.
A: Kidney → Ureter → Bladder → Urethra.
Q: Explain how gas exchange occurs in the alveoli — what moves where, and why?
A: Oxygen diffuses from the alveoli into the surrounding blood capillaries (moving from high to low concentration), while carbon dioxide diffuses from the blood into the alveoli to be breathed out. The alveoli's thin walls and large surface area help this diffusion happen efficiently.
Q: Where does most nutrient absorption into the blood occur, and what structures increase its surface area to help this?
A: The small intestine; villi (tiny finger-like projections lining its walls) increase the surface area for absorption.
Q: Put these in order to show the general path of blood as it circulates: Veins, Heart, Capillaries, Arteries.
A: Heart → Arteries → Capillaries → Veins → back to Heart.
Q: Explain how the respiratory, digestive, circulatory and excretory systems work together to support cellular respiration in body cells.
A: The respiratory system brings in oxygen; the digestive system breaks food down into glucose and other nutrients; the circulatory system transports the oxygen and glucose to body cells (where cellular respiration happens) and carries away wastes; the excretory system removes those wastes (e.g. CO2 via the lungs, urea via the kidneys) from the body.