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Nutrients in humans - Coggle Diagram

- - - - haemoglobin is broken down and the liver stores the iron that is released
      - Bile pigments are also formed from the breakdown of haemoglobin
- - - - The stomach has strong distensible muscular bag with thick and well developed muscular walls. The stomach has many gastric pits which leads to the gastric glands that secretes the gastric juices. the gastric juice is a dilute solution of Hydrochloric acid with a pH of 2. Gastric juices also contains mucus and protease called pepsin.
      - The dilute HCL denatures the amylase from the mouth because of its low pH. pepsinogen is activated by HCL to become pepsin. HCL provides slight acidic medium which is suitable for the activation of pepsin. HCL also kills the harmful bacteria in the food.
      - proteins are broken down by pepsin to form polypeptides. Food remains in the stomach for about 3 to 4 hours. The partially digested food becomes becomes liquified, forming chyme. The chyme will pass through duodenum in small amounts when the pyloric spincter relaxes and opens.
    - - Characteristics
        
        Has a U-shape duodenum, jejunum and ileum
        
        it is 6m long
        
        the lining of the walls contains glands that secrete digestive enzymes
        
        wall of the small intestine is also adapted to absorb digested food products and water
      - Chyme enters the small intestine
        
        stimulates the pancreas to secrete pancreatic juice
        
        pancreatic juice contains amylase, trypsin and pancreatic lipase which pass through the pancreatic duct into duodenum
        
        2.stimulate the gall bladder to release bile
        
        no enzyme but increases the rate of digestion
        
        bile pass through bile duct to duodenum
        
        Stimulate epithelial cells in small intestine to produce enzymes such as maltose, lipase and peptide
    - - alkaline substances
        
        pancreatic juice
        
        bile
        
        intestinal juice
        
        these then neutralizes the acidic chyme
        
        provides suitable alkaline medium for action of pancreatic and intestinal enzyme
    - - carbohydrate digestion
        
        lactose
        
        lactose + lactase = glucose + galactose
        
        sucrose
        
        sucrose + sucrase = glucose + fructose
        
        cellulose
        
        human cannot digest cellulose as there is no digestive enzyme for cellulose
      - starch
        
        starch + pancreatic amylase = maltose
        
        maltose + maltase = glucose
      - Therefore, carbohydrate is digested to form simple sugars which is then absorbed into blood stream
      - Protein digestion
        
        protein + pepsin = polypeptides (in the stomach)
        
        undigested protein goes to the small intestine and is further broken down
        
        protein + trypsin = polypeptides
        
        polypeptides + peptidase (erepsin) = amino acids
      - Fat digestion
        
        bile salt emulsifies fats
        
        lower surface tension tension of the fat reduce the attractive forces between the fat molecules
        
        fat break into tiny fats droplets suspended in water forming emulsion
        
        physical break up, no chemical digestion of the fat molecules has occurred yet
        
        emulsification increases the surface area to volume ratio of the fats, speeding up their digestion of lipase
        
        Emulsifies fat + lipase =fatty acid + glycerol
  - - - Surface area of small intestine
        
        inner surfaces are folded
        
        the folds have many finger like projections called villi
        
        villi structure
        
        have epithelial cells that have numerous microvilli which increases the surface area
        
        have thin walls that are 1 cell thick
        
        have either a lacteal or lymphatic capillary surrounded by blood capillaries
        
        Lymphatic capillaries of the villi transports fats
        
        Blood capillaries of the villi transport sugars and amino acids
      - There are membranes that separates the food substances from the blood capillaries, allowing digested food substances to pass through a thin membrane instead of a thick one
      - The concentration gradients of individual food substances
      - The small intestine is long enough to provide sufficient time for absorption
    - - Glucose and amino acids are absorbed by diffusion into the blood capillaries of the villi
      - They are also absorbed via active transport. This occurs when there is a lower concentration of these food substances in the lumen of the small intestine than in the blood capillaries
      - glycerol and fatty acids diffuse into the epithelium where they combine to form minute fat globules which enter the lacteals
  - - - blood capillaries will unite to form larger blood vessels, which in turn will unite to form a large vein called the hepatic portal vein
      - hepatic portal vein transport nutrients to the liver
      - in the liver
        
        sugar will be converted to glycogen in the liver and stored
        
        some glucose is also transported by the blood leaving the liver and is distributed around the body
        
        glucose is assimilated and then oxidized during tissue respiration to release energy for the vital activities of the cells
        
        excess glucose is then returned to the liver and stored as glycogen. Insulin, a hormone produced by the liver, stimulates the liver cells to convert excess glucose to glycogen
        
        when the body is in need of energy, the liver converts glycogen back to glucose which is then transported around the body by the blood to the cells
        
        Amino acids which enter the cells are converted into new protoplasm that is used for growth and repair of worn-out parts of the body.
        
        amino acids are also used to form enzymes and hormones
        
        excess amino acids are deaminated into urea
    - - Fats are absorbed into lymphatic capillaries. the lymphatic capillaries join to form larger lymphatic vessels, which discharges fats into the blood stream
      - fats are converted into forms that can either be broken down or stored
      - when there is enough glucose, fats are not broken down and are used to build protoplasm for cell membranes
      - when there is not enough glucose, fats are broken down to provide the energy needed for vital activities of the body.
      - excess fats are stored in special tissues called adipose tissues
        
        This occurs beneath the skin and around the heart and kidneys. Adipose tissues protect these organs by acting as shock absorbers
- - - - it slows down the brain functions (effects vary from one person to another)
    - - under the influence of alcohol, a person becomes carefree as alcohol takes away their inhibitions. decreasing self control
    - - a person starts having slurred speech
      - blurred vision
      - poor muscular co ordination
      - clumsy
      - unable to walk steadily