Animal tissues, organs and systems

• Circulatory system


  Transports substances around the body
• Heart


  An organ
• Heart


  Pumps blood around the body
• Heart walls


  Muscle tissue
• Types of heart chambers

  • Atria
  • Ventricles
• Atria


  Upper chambers of the heart
• Ventricles


  Lower chambers of the heart
• Blood flow in the heart

  1. Atria pump blood to ventricles

  2. Ventricles pump blood out of the heart
• Heart valves


  Prevent backflow of blood
• Blood flow after leaving the heart

  1. Right side - to the lungs

  2. Left side - to the rest of the body
• Arteries


  Blood vessels that carry blood away from the heart
• Veins


  Blood vessels that carry blood back to the heart
• Aorta


  Blood vessel that carries blood from the left ventricle to the rest of the body
• Vena cava


  Blood vessel that carries blood from the rest of the body to the right atrium
• Pulmonary artery


  Blood vessel that carries blood from the right ventricle to the lungs
• Pulmonary vein


  Blood vessel that carries blood from the lungs to the left atrium
• Arteries


  • Thick walls containing thick muscle tissue and elastic fibres
• Veins


  • Thinner walls, with thinner muscle tissue and contain valves
• Capillaries


  • Very thin walls (only one cell thick) to reduce distance diffusion has to occur across
  • Very narrow to reduce distance diffusion has to occur across
• Pacemaker


  Located in the right atrium
• Lungs


  Located in the upper part of the body (thorax)
• Ribcage


  Protects the lungs
• Diaphragm


  Separates the lungs from the abdomen
• Gas exchange in the lungs

  1. Oxygen diffuses into the bloodstream

  2. Carbon dioxide diffuses out of the bloodstream
• Trachea


  Carries air from the nose/mouth towards the lungs
• Bronchi


  Airways that the trachea splits into
• Bronchioles


  Smaller airways that the bronchi split into
• Alveoli


  Small gas exchange structures in the lungs
• Alveoli


  • Thin walls (one cell thick)
  • Good blood supply - extensive capillary network covering the surface of each alveolus
  • Efficient movement of blood through capillaries to maintain a concentration gradient for diffusion of oxygen & carbon dioxide
  • Folded inner surface to give a large surface area
• Blood


  A tissue
• Plasma


  The liquid part of blood
• Main blood cell types

  • Red blood cells
  • White blood cells
  • Platelets
• Transport by blood plasma

  1. Carbon dioxide from organs to lungs

  2. Soluble products of digestion from small intestine to other organs

  3. Urea from liver to kidneys
• Red blood cells


  Transport oxygen
• Red blood cells


  Lack a nucleus
• Red blood cells


  Contain haemoglobin
• Haemoglobin in the lungs

  Haemoglobin + oxygen ⇌ oxyhaemoglobin
• White blood cells


  Defend the body against microorganisms
• Platelets


  Help clot the blood at wound sites
• Coronary arteries


  Blood vessels that supply the heart muscle tissue