B4-Organsing animals and plants

• Heart

  An organ that pumps blood around the body in a double circulatory system
• Blood circulation

  1. Right ventricle pumps blood to the lungs for gas exchange

  2. Left ventricle pumps blood around the rest of the body
• Coronary arteries


  • Supply oxygen rich blood to the heart muscle
• Pacemaker

  A group of cells in the right atrium that control the natural resting heart rate
• Artificial pacemaker


  Used to correct irregularities in the heart rate
• Lungs


  Where oxygen and carbon dioxide are exchanged in the tiny air sacs (alveoli)
• Alveoli


  • Surrounded by capillaries where gas exchange takes place
• Blood vessels


  • Arteries
  • Veins
  • Capillaries
• Arteries


  • Carry blood away from the heart
  • Thick muscular walls
  • Small lumen
  • Carry blood under high pressure
• Veins


  • Carry blood to the heart
  • Thin walls
  • Large lumen
  • Carry blood under low pressure
  • Have valves
• Capillaries


  • Connect arteries and veins
  • One cell thick
  • Carry blood under very low pressure
• Blood components


  • Plasma
  • Red blood cells
  • White blood cells
  • Platelets
• Plasma


  Pale yellow fluid part of blood that transports cells, CO, hormones and waste
• Red blood cells


  • Have no nucleus (more room to carry O₂)
  • Contain the red pigment haemoglobin which carries O₂
  • Have a large surface area to volume ratio for faster diffusion of oxygen
• White blood cells


  • An important part of the immune system, some produce antibodies and others surround and engulf foreign cells, all have a nucleus
• Platelets


  • Tiny fragments of cells (no nuclei)
  • Clump together to help form clots, protect the body by stopping/reducing bleeding
• Atherosclerosis


  A cause of coronary heart disease where layers of fatty material build up inside the coronary arteries, narrowing them
• Risk factors for coronary heart disease

  • Smoking
  • High blood pressure
  • High cholesterol
  • Lack of exercise
• Stents


  Metal cylinder grids inserted into an artery to maintain blood flow by keeping the artery open
• Statins


  Drugs that lower harmful cholesterol in the blood and stop the liver producing too much cholesterol
• Faulty heart valves


  Heart valves that do not open fully or do not close fully, preventing blood from flowing in the right direction
• Causes of faulty heart valves

  • Being born with it (congenital heart disease)
  • Having had rheumatic fever
  • Cardiomyopathy
  • Damage from a heart attack
  • Getting older
  • Endocarditis
• Heart transplant


  Donor hearts from a person who has died are used to replace the diseased heart of a patient
• Artificial heart


  Used to keep patients alive whilst waiting for a heart transplant, or to allow the heart to rest as an aid to recovery
• Plant tissues


  • Epidermal
  • Palisade mesophyll
  • Spongy mesophyll
  • Xylem and phloem
  • Meristem
• Leaf


  A plant organ that is the site of photosynthesis and respiration
• Guard cells


  • Open and close the stomata to let gases diffuse in and out and control water loss
• Transpiration


  1. Xylem tissue transports water and mineral ions from the roots to the stems and leaves

  2. Phloem tissue transports dissolved sugars from the leaves to the rest of the plant
• Potometer


  An apparatus used to estimate the rate of transpiration by measuring water uptake