Nutrition and digestive system

• Pepsin- a protein digestive enzyme
• A balanced diet is one which contains a correct dosage of each food group group, this can be influenced by: age, sex, level of activity and body type and dietary choices such as veganism or vegetarian.
• 30% carbohydrates - high fibre

  30% (or more) fruits and vegetables

  25% protein

  5% unsaturated fats and oils
• Diet differences:

  Vegan

  vegetarian

  Kosher

  Halal
• Malnutrition -> eating an unbalanced diet can lead to malnutrition

  -this means there is an imbalance in your diet

  -there may be deficiency or an excess of a nutrient(s) that leads to poor health when malnutrition is severe, a nutritional disease or disorder. results.
• Kwashiorkor-> a severe form of malnutrition that is most common in developing regions due to lack of protein

  signs: to much fluid in the body's tissues wich therefore causes swelling under the skin.
• Marasmus -> due to a lack of all the main food groups

  -slow starvation

  -loss of muscle and body weight
• Anorexia-> self-induced starvation and death due to sychological problems associated with food
• Bulimia-> the 'sufferer' appears totally normal but 'purges' (induces vomiting) after eating or takes laxatives so that they do not absorb the food into their body

  -after lengths of time this can become automatic
• Obesity-> Due to over-intake of food generally mostly carbohydrates and lipids

  this increases the risk of coronary heart disease and type 2 diabetes
• Defiency diseases:

  1. Calcium-> (rickets in children)(osteoporosis in adults
• Food intolerance -> difficulty ingesting

  -the bodys normal processes are not adapted to cope well with substance

  eg: Celiacs disease

  symptoms

  -abdominal cramps or discomfort

  -indigestion
• Food allergies -> Immune system overreacts to a harmless substance food protein.

  ->antibodies are released (inappropriate immune response)
• Human Digestive System:

  food:

  -provides energy

  -provides materials for growth

  -regulation of processes in the body
• Ingestion-> taking in if the food
• Digestion-> mechanical(tongue, mouth, salivary glands) and chemical breakdown (breaking down of food into its monomers)
• Absorption-> The nutrients going from your digestive into your bloodstream
• Assimilation -> the nutrients are transported via the blood stream and then enter the body's cells and become part of cellular metabolism
• Egestion -> the waste products or unabsorbed remains in the gut

  (dead cells, bacteria etc.) are compacted and dehydrated to form faeces .

  they are then exited from the body
• Alimentary Canal:

  • mouth
  • teeth
  • tongue
  • Salivary glands (ao)
  • Pharynx
  • Epiglottis

  -

  • Esophagus
  • Liver (ao)
  • Stomach

  -

  • Gallbladder (ao)
  • pancreas (ao)
  • Large intestine
  • small intestine
  • appendix (ao)

  -

  • Rectum
  • Anus
• Mouth-> the tongue and teeth begin mechanical breakdown

  • three pairs of salivary glands -secrete saliva into mouth cavity

  -Parotid gland

  -Submandibular gland

  Sublingual gland
• Saliva is slightly Alkaline PH (7.8/8) -contains mucus that will moisten the food and help to form the Bolus

  -contains salivary Amylase - a type of carbohydrase enzyme

  Bolus (masticated food)
• Types of teeth

  1. Incisor
  2. Canine
  3. Premolar
  4. Molar

  Fluoride-is a mineral that helps to rebuild and strengthen the tooths surface, or enamel
• Oesophagus-> the bolus enters the oesophagus and is transported to the stomach
• Peristalsis -> this is the alternative wave like contractions of circular and longitudinal muscles in the gut wall
• Epiglottis-> a flap of cartilage closes off the opening to the trachea (windpipe) during swallowing
• Sphincters -> at the lower end of the oesophagus is the first of a number of sphincters, these are ring like muscles that compartementalize the gut into separate regions

  -if this sphincter does not do its job it will let the acid from the stomach contents to reflux into the oesophagus, causing pain and discomfort.
• Stomach-> consists of three layers of involuntary muscles that churn the stomach contents.

  -Glands in the wall of the stomach release gastric juice.
• The secretion of gastric juice is stimulated by the secretion of the hormone gastrin.
• A hormone is a chemical substance which is used to carry information from one part of the body to another.
• Gastrin secretion is stimulated by chewing and swallowing, food entering the stomach, or even just thinking about food.
• Proteases ->a digesting enzymes that start the digestion of proteins.
• HCl- (hydrochloric acid) to create an acidic environment (pH 2). HCl provides the optimum pH for the functioning of the enzymes and acts as an anti-septic (kills microbes).
• mucus- to protect the stomach from the acid, and to help liquefy the ‘food’
• Ulcers are caused by stress and unhealthy eating, including pharmaceutical drugs taken on an empty stomach.
• chyme->When the stomach contents resembles ‘soup’, it is referred to as chyme.
• SMALL INTESTINE-> 4-6m ,

  3 regions:

  -duodenum

  -Jejunum

  -ileum
• Duodenum-> completes the digestion of proteins and starts the hydrolysis of lipids and carbohydrates

  adapted for the following:

  • glands in the gut secrete intestinal juice containing all enzymes needed (carbohydrase, protease and lipase)to complete chemical digestion.
  • when the chyme enters the duodenum it stimulates the secretion of the hormone (Secretin) which then stimulates the secretion of intestinal juice
• Digestive enzymes are also released from the pancreas in pancreatic juice
• Bile-> produced in the liver ->stored/secreted in the gall bladder

  -helps to emulsify lipids mostly fats

  -promotes peristalsis