Animal Tissues, Organs and Systems

• What is the main function of the digestive system?

  To break down food so it can be digested and to provide nutrition to the body.
• What is the role of the pancreas and the salivary gland in the digestive system?

  They produce digestive juices containing enzymes.
• What is the role of the stomach in the digestive system?

  Produces Hydrochloric acid - which kills any bacteria present and provides the optimum pH for the enzyme protease to function
• What is the role of the small intestines in the digestive system?

  The site where soluble materials are absorbed into the bloodstream.
• What is the role of the liver in the digestive system?

  Produces bile, which is stored in the gall bladder, which emulsifies (to disperse) lipids and allows the lipase enzyme to work more efficently
• What is the role of the large intestine in the digestive system?

  Absorbs water from undigested food, forming faeces.
• What is the role of enzymes in the digestive system?

  They act as biological catalysts which speed up the rate of biological reactions without being used up.

  They break down large insoluble foods into smaller soluble foods.
• How does the shape of an enzyme affect its function?

  Enzymes have an active site which fits a particular substrate

  
• What is metabolism?

  The sum of all reactions in a cell or organism
• What is the lock and key model of enzyme function?

  The shape of the enzyme and the active site are complementary, so can bind together to form an enzyme-substrate complex

  A) Enzyme-substrate complex

  
• How does temperature affect enzyme action?

  Up to a certain point, increasing temperature increases enzyme action as there is more kinetic energy.

  
  

  Above a certain temperature, the enzyme becomes denatured (the active site changes shape and no longer can fit the substrate), so it can no longer catalyse the reaction.

  
  

  The optimum temperature is 37 degrees Celcius.
• How does pH affect enzyme function?

  The optimum pH for most enzymes is 7, however protease in the stomach has an optimum at a much lower pH.

  If the pH becomes too extreme the enzyme may become denatured and no longer catalyse reactions.
• Where are carbohydrases, proteases and lipases produced in the body?

  Carbohydrases: amylase - salivary gland and pancreas, maltase - small intestine.

  Proteases: Pepsin - stomach; others - pancreas, small intestine

  Lipases: Pancreas, Small intestine
• What is the role of carbohydrases in the digestive system?

  They break down carbohydrates into monosaccharides and disaccharides. Amylase breaks down starch into maltose, and maltase breaks down maltose into glucose.
• What is the role of protease in the digestive system?

  Breaks down proteins into amino acids.
• What is the role of lipases in the digestive system?

  Lipase breaks down the lipids into fatty acids and glycerol.
• How are the products of digestion used?

  They are used to build bigger molecules such as carbohydrates and proteins

  The glucose is used in respiration

  (Oxygen + Glucose -> Carbon Dioxide+ Water)
• Where is bile made and stored

  Made - Liver

  Stored - Gall Bladder
• What is the role of bile in the digestive system?

  Bile is an alkaline substance which neutralises the hydrochloric acid secreted from the stomach.

  Bile allows lipids to form droplets - increases the surface area for the lipase enzyme to work on
• What is the heart?

  An organ that pumps blood around the body.
• Label this.

  Label

  A) Substrate

  B) Active Site

  C) Enzyme

  D) Enzyme-substrate complex

  
• What is the purpose of the circulatory system?

  Carry oxygen and other useful substances to bodily tissues, and removes waste products.
• How does the double circulatory system work?

  One pathway carries blood from the heart to the lungs, where gaseous exchange of oxygen and carbon dioxide occurs

  One pathway carries oxygenated blood from the heart to the bodily tissues
• Label the heart

  A) Right Side

  B) Left side

  C) Pulmonary Artery

  D) Vena Cava

  E) Right Atrium

  F) Heart Valve

  G) Tendons attached to valve and heart wall

  H) Right Ventricle

  I) Left ventricle

  J) Heart Valve

  K) Left atrium

  L) Pulmonary Vein

  M) Aorta

  
• Where does the blood pumped by the right ventricle go to?

  The lungs
• Where does blood pumped by the left ventricle go to?

  The body
• Why is the double circulatory system so important?

  It makes the system more effective
• How many chambers of the heart are there and what are they called?

  Four chambers: left atrium, left ventricle, right atrium, and right ventricle.
• Why is the wall of the left ventricle thicker?

  The left ventricle has to pump blood at a higher pressure to the rest of the body.
• What are the four main blood vessels associated with the heart

  Aorta (Left) - carries oxygenated blood from the heart to the body.

  Pulmonary Vein (Left) - carries oxygenated blood from the lungs to the heart.

  Vena Cava (Right) - carries deoxygenated blood from the body to the heart.

  Pulmonary Artery (Right) - carries deoxygenated blood from the heart to the lungs.

  
• Give some tips to help memorise the heart more easily!

  Pulmonary always refers to the lungs

  The aorta, Artery etc always start with an A which stands for Away from the heart
• What is the purpose of valves in the heart?

  To prevent the black flow of blood.
• What is the purpose of coronary arteries?

  Coronary arteries supply the heart with oxygenated blood.
• Describe the process of blood flow through the heart.

  • Blood enters the right atrium through the vena cava and the left atrium via the pulmonary vein
  • The atria contract, forcing blood into the ventricles and causing the valves to shut
  • After the ventricles contract deoxygenated blood in the right ventricle enters the pulmonary artery and the oxygenated blood in the left ventricle enters the aorta carrying blood to the body.

  
• What is the approximate value of a natural resting heart beat?

  70 bpm
• How is the heartbeat controlled?

  Heart rate is controlled by a group of cells in the right atrium called pacemaker cells, they release waves of electrical activity which causes the heart to contract.
• How can an irregular heartbeat be treated?

  Planting an artificial pacemaker, which sends electric signals to correct the heart rhythm
• What are the three types of blood vessels in the body?

  Arteries, veins, capillaries
• How are arteries adapted to their function?

  Function: Carry blood away from the heart.

  Thick muscle layer - adds strength to resist high-pressure

  Thick elastic layer - allows arteries to stretch and recoil - in order to withstand high pressure
• How are veins adapted to their function?

  Function: Carry blood to the heart

  Wide Lumen - enables low pressure

  Valves - Prevent backflow of blood

  (tip: veins have valves, they both begin with V)