Animal tissues, organs and systems

• The pancreas and the salivary gland are glands which produce digestive juices containing enzymes
• The main function of the digestive system is to digest food and absorb nutrients.
• The stomach produces hydrochloric acid, which kills bacteria and provides the optimum acidic pH for the enzyme protease
• The small intestine is where soluble food molecules are absorbed into the bloodstream.
• The liver produces bile, which is stored in the gallbladder
• The large intestine absorbs water from undigested food to produce faeces.
• Enzymes act as biological catalysts which speed up reactions without being used
• Match the enzyme feature with its description:

  Active site ↔️ Specific region for substrate binding

  Substrate ↔️ Molecule acted upon by enzyme
• Examples of metabolic reactions catalysed by enzymes:

  1️⃣ Building larger molecules from smaller molecules

  2️⃣ Changing one molecule to another

  3️⃣ Breaking down larger molecules into smaller molecules
• The lock and key hypothesis states that the enzyme active site and the substrate have complementary shapes.
• Up to a certain point, increasing temperature increases enzyme action, but above that, enzymes become denatured
• Match the enzyme with its production location:

  Carbohydrase ↔️ Salivary gland and pancreas

  Protease ↔️ Stomach and pancreas

  Lipase ↔️ Pancreas and small intestine
• Carbohydrases break down carbohydrates into monosaccharides
• Proteases break down proteins into amino acids.
• Lipases break down lipids into fatty acids and glycerol
• Bile is made by the liver and stored in the gallbladder.
• The circulatory system carries oxygen and nutrients to tissues while removing waste
• Match the circulatory pathway with its function:

  Heart to lungs ↔️ Gaseous exchange of oxygen and carbon dioxide

  Heart to tissues ↔️ Delivers oxygenated blood
• The left ventricle has a thicker wall because it pumps blood at higher pressure around the body.
• The heart has four chambers: the right and left atria, and the right and left ventricles
• Match the blood vessel with its function:

  Aorta ↔️ Carries oxygenated blood to the body

  Pulmonary vein ↔️ Carries oxygenated blood from lungs to heart

  Vena cava ↔️ Carries deoxygenated blood to heart
• Valves in the heart prevent the backflow of blood.
• Coronary arteries supply the heart muscle with oxygenated blood
• Steps of blood flow through the heart:

  1️⃣ Blood enters right atrium via vena cava, left atrium via pulmonary vein

  2️⃣ Atria contract, forcing blood into ventricles

  3️⃣ Right ventricle pumps blood to pulmonary artery, left ventricle pumps blood to aorta
• The average resting heart rate is approximately 70 beats per minute.
• Heart rate is controlled by a group of cells in the right atrium called a pacemaker.
• Adaptations of arteries:

  1️⃣ Thick muscle layer for strength

  2️⃣ Thick elastic layer for stretching and recoiling
• Match the blood vessel with its adaptation:

  Arteries ↔️ Thick elastic layer

  Veins ↔️ Valves to prevent backflow

  Capillaries ↔️ Walls one cell thick
• The lungs are located in the thorax
• The diaphragm separates the lungs from the abdomen.
• Oxygen diffuses from the alveoli into the bloodstream
• Alveoli are small and arranged in clusters to increase surface area for gas exchange.
• The substance that carries blood components around the body is called plasma
• Match the blood component with its role:

  Red blood cells ↔️ Carry oxygen

  White blood cells ↔️ Fight infection

  Platelets ↔️ Aid blood clotting
• Smoking is a known factor that can lead to cancer.
• Why are alveoli arranged in clusters and small in size?

  To increase surface area
• Alveoli have a rich blood supply to maintain a concentration gradient
• A thin alveolar wall allows for a shorter diffusion pathway.
• How is breathing rate calculated?

  Breaths per minute
• The substance that carries blood components around the body is called plasma