human nutrition and transport

• digestion


  breakdown of food from large insoluble molecules to smaller soluble molecules which can be absorbed into blood
• chemical digestion


  use of enzymes to break down food into smaller molecules
• mechanical digestion


  breakdown of food by chewing or grinding
• peristalsis


  a series of wave like motions of circular and longitudinal muscles squeezing, contracting and relaxing to push the bolus
• peristalsis is present in…

  oesophagus

  small intestine

  large intestine
• bile


  emulsifies large lipids into small fat droplets to increase surface area for lipase
• inegestion


  taking nutrients in the body
• absorption


  transport/delivery of digested molecules and nutrients into the body tissue
• assimilation


  absorbed food is used to provide essential energy
• egestion


  removal of undigested foods and waste products
• urea


  a toxic chemical produced from the breakdown of excess amino acids in the liver
• excretion


  removal of toxic materials, the waste products of metabolism and excess material
• metabolism

  chemical processes going on in the body
• cortex


  outer layer packed full of filters called nephrons
• medula


  middle layer which has tubes carrying filtered waste to the centre of the kidneys
• pelvis 


  area where all collecting ducts come together and connect with the ureter
• nephrons


  made of. kidney tubule
• tubule


  little tube
• convoluted


  twisted
• distal


  distance
• proximal


  close
• nephrons


  filtration unit in kidneys
• ultrafiltration


  where the filter seperates different sized molecules under pressure
• reabsorption 


  molecules and ions which are required by the body are taken back from the nephron
• release of waste


  waste products to be excreted, travel to the ureter down to the bladder
• osmoregulation


  keep water levels constant
• homeostasis

  physiological process where internal systems are maintained at equilibrium despite external factors
• ADH 


  control the amount of water absorbed in the kidney nephrons
• permeable


  how much water can be absorbed
• blood


  red blood cells, white blood cells, plasma, platelets
• plasma


  pale yellow liquid that carries just about everything needed for the body e.g. urea, hormones…
• platelets


  blood clotting
• red blood cells


  carry oxygen from the lungs and deliver it throughout the body
• white blood cells


  helps to protect against infection and foreign pathogens
• phagocytosis


  process of a phagocyte engulfing and destroying a pathogen
• engulf


  surround/cover completely
• antibodies


  specific proteins produced by lymphocytes to identify antigens and attack/destroy them
• antigens


  protein markers on surface of a pathogen to allow it to be identified as foreign
• antitoxin


  produced by body to neutralise toxins produced by pathogens
• ingest 


  consumption of a substance by a microorganism