Multicellular Organisms

• What does the cerebellum control?

  Balance and coordination
• What does the cerebrum control?

  Memory and conscious thoughts
• what does the medulla control

  Heart rate and breathing rate
• Where do hormones travel

  The bloodstream
• What is mitosis?

  A type of cell division
• How many pairs of chromosomes are in a diploid human body cell?

  23 pairs of chromosomes
• What is shown in the diagrams mentioned?

  Only two pairs of chromosomes
• First stage of mitosis

  The DNA in chromosomes copies itself
• Stage 2 of mitosis

  Prophase

  The DNA in chromosomes and their copies condenses to become more visible. The membrane around the nucleus disappears
• Stage 3 of mitosis

  Chromosomes and their copies line up in the middle of the cell.
• Stage 4 of mitosis

  Chromosomes and their copies are pulled to different ends of the cell
• Stage 5 of mitosis

  New membranes form around the chromosomes at each end of the cell.
• Stage 6 of mitosis


  The cell membrane pinches in and eventually divides into two daughter cells.
• How many chromosomes does an embryo have

  46 (diploid)
• Examples of stem cells

  Embryonic

  Tissue
• Increase in blood glucose levels

  • Increase in blood glucose is detected by receptors in the pancreas
  • Pancreas then produces insulin
  • This travels in the blood to the liver
  • The liver then converts glucose and stores it as glycogen
  • This brings glucose concentration back to normal
• Decrease in blood glucose levels

  • Decrease in blood glucose is detected by receptors in the pancreas
  • Pancreas produces the hormone glucagon
  • Glucagon travels in the blood to liver
  • The liver then converts glycogen and stores it as glucose
  • This causes blood glucose to return to normal
• How can blood glucose decrease 


  Missing a meal or exercise
• How can blood glucose increase

  Eating
• Sensory neuron

  Pass sensory information to the central nervous system
• Inter neuron

  Operates in the central nervous system
• Motor neurones

  Enables a response to occur at an effector
• Plant organs include

  Leaves, roots and stem
• Water is used for

  • Photosynthesis, support
  • Transport of minerals + sugar
  • Cooling through evaporation
• Xylem

  • Transports water + minerals in the plant
  • Composed of dead material
  • Contains rings of lignin for support
• Leaf structure contains

  • Vein
  • Mesophyll
  • Stomata
  • Guard cells
  • Upper epidermis
  • Lower epidermis
• Transpiration

  The process of water moving through a plant and its evaporation through stomata
• Functions of veins

  • Carry blood towards the heart
  • Low blood pressure
  • Thinner muscle layer
• Red Blood Cells

  • Transports hormones as well as nutrients, oxygen carbon dioxide and urea
  • They are described as bioconclave shape
  • Carry oxygen from lungs to body cells
  • Able to do this because of haemoglobin
  • When haemoglobin is reacted to with oxygen it formed oxyhemoglobin
• Structure of a leaf

  • Upper epidermis
  • Palisade mesophyll
  • Spongy mesophyll
  • Stoma
  • Lower epidermis
  • Guard cells
  • Vein
• White blood cells

  • Larger than red blood cells
  • Two main types phagocytes + lymphocytes
  • phagocytes, destroy pathogens by engulfing them and then destroying using enzymes
  • lymphocytes, these destroy pathogens by producing chemicals called antibodies
• Properties of arteries

  • Carries blood away from heart
  • High blood pressure
  • Narrow channel + thick muscular walls
  • Pulmonary arteries carry deoxygenated blood from right ventricle to lungs
• Coronary Artery

  • Coronary branches off of the aorta and supplies the heart with oxygen + glucose for aerobic respiration . This allows the heart to contract
• Functions of the capillaries

  • Very thin walls
  • Carry blood through tissues and organs
  • Network of capillaries has large surface area
• Four chambers of the heart

  • left ventricle
  • left atrium
  • right ventricle
  • right atrium
• Features that increase absorption

  • Large surface area
  • Thin walls
  • Extensive blood supply
• Structure of the lungs

  • Trachea
  • Bronchi
  • Bronchioles
  • Alveoli
• How are alveoli suited to their function

  • Large surface area
  • Short distance
  • Thin walls
  • Good blood supply
• What is organs are part of the alimentary canal

  • Oesophagus
  • Stomach
  • Small intestine
  • Large intestine
  • Rectum
  • Anus
  • Mouth
• What organs are part of the associated organs

  • Salivary gland
  • Pancreas
  • Appendix
  • Gall bladder
  • Liver