Human nutrition Flashcards iGCSE Biology

[q] What is Assimilation?

[a] Assimilation is the movement of digested food molecules into the cells of the body where they are used, becoming part of the cells.

[q] What is Chemical Digestion?

[a] Chemical Digestion is the breakdown of large, insoluble molecules into small, soluble molecules.

[q] What are the effects of lack of Vitamin D in Human Body?

[a] Effects of lack of Vitamin D in Human Body are:

• Muscle cramps;
• Rickets (soft/bent bones);
• Stunted growth;
• Prone to infections;
• Fatigue;
• Reduced ability to absorb calcium (ions);

[q] What causes Anaemia in Human Body?

[a] Lack of Iron in Human Blood causes Anaemia.

[q] What are the effects of Anaemia?

[a] Weak, tired, and irritable because of lack of oxygen.

[q] How does the Rickets look like?

[a] Rickets look like:

[q] How does Scurvy looks like?

[a] Scurvy looks like:

[q] What causes Diarrhoea?

[a] Diarrhoea is caused by Bacterial or viral infection (e.g: Cholera, lactose intolerance, food allergies).

[q] What are the effects of Diarrhoea?

[a] The effects of Diarrhoea are as follows:

• Dehydration
  
  • Lining of the digestive system is damaged resulting in the intestines being unable to absorb fluid.
    
• Loss of salts and ions
  
• Decrease in volume of blood/blood pressure;
  
• Increase in blood concentration;
  
• Death, Coma

[q] What is the treatment of Diarrhoea?

[a] Treatment for Diarrhoea is:

• Oral rehydration therapy
  
• Drink a mixture of sugar and salts to replace lost water.
  
• Water must be uncontaminated.
  
• Antibiotics might be added.

[q] What are the Dietary needs of humans?

[a] The Dietary needs of humans

• Age
  
  • Children
    
    • More energy needed for growth and the extra energy associated with maintaining their body temperature.
    • More protein, minerals and vitamins.
  • Adults
    
    • Energy needs of adults decreases as they age

• Activity levels
  
  • More active individuals require more energy, as muscles are contracting more and respiring faster.

• Pregnancy/Breastfeed
  
  • More energy needed for supporting growth of developing fetus
  • More Protein, calcium, iron, vitamin D or folic acid

• Gender
  
  • Females have lower energy requirements than males.
    
    • Females have a lower body mass than males, which has a lower demand on energy intake,
    • Different physical demands made on boys and girls

[q] What is meant by Egestion?

[a] Egestion is the passing out of food that has not been digested or absorbed, as faeces, through the anus.

[q] Explain how tooth decay occurs?

[a]

1. Food remains on teeth;
   
2. Bacteria breakdown sugars and respires, producing acid;
   
3. Acid erodes enamel;
   
4. Dentine is exposed;
   
5. Dentine is softer than enamel;
   
6. Decay reaches nerve endings leading to pain;
   
   

   1. Food remains on teeth;
   2. Bacteria, use / breakdown, sugars / carbohydrate / sweet foods;
   3. Respiration;
   4. Acid is produced;
   5. Acid, dissolves / erodes / destroys / wears away / AW, enamel;
   6. Dentine is exposed / AW;
   7. Dentine, softer / dissolves more rapidly (than enamel);
   8. AVP; e.g. Decay reaches nerve endings leading to pain.

[q] What are the Functions of Human Teeth?

[a] Functions of Human Teeth are:

• Incisor → cutting and biting
  
• Canine → tearing, holding and biting
  
• Premolar → chewing and crushing
  
• Molar → chewing and grinding

[q] How does Cholera causes Diarrhoea?

[a] 

• Cholera is a disease caused by bacteria present in contaminated food and water.
• When cholera bacteria are ingested, they multiply in the small intestine and invade its epithelial cells, releasing toxins which irritate the intestinal lining and lead to the secretion of chloride ions by active transport
• This decreases the water potential of the gut contents, causing water from surrounding tissues and blood into the gut by osmosis.
• This makes the undigested food much more watery, leading to acute diarrhoea, and the loss of body fluids and salts leads to dehydration and kidney failure.

[q] What is the Ingestion?

[a] Ingestion is the taking of substances into the body through the mouth. 

e.g. food and drink.

[q] Label the parts of the tooth:

[a]

• A: Enamel
• B: Dentine
• C: Pulp / pulp cavity / nerve / sensory neurone / capillaries / blood vessels
• D: Gum

[q] What are the Functions of Liver?

[a]

• Bile production;
  Emulsify fats by breaking up of large fat globules into smaller fat globules;
  Increases surface area to speed up enzyme action.
  Excretory products put in bile; e.g. Cholesterol.
  
• Assimilation of digested food such as glucose;
  
• Homeostasis;
  
• Deamination of amino acids;
  Removal of nitrogen-containing part of amino acids;
  To produce urea;
  
• Breakdown of
  hormones, toxins, alcohol and drugs;
  Worn out red blood cells;
  
• Storage of iron, vitamin A and vitamin D;
  
  • bile production / AW;
  • breakdown / remove, hormones / red blood cells / toxins / alcohol / drugs;
  • storage of, iron / vitamin A / vitamin D ;
  • AVP;
  • e.g. cholesterol, synthesis / AW
  • Deamination (of amino acids);
  • Removal of nitrogen-containing part of amino acids;
  • To produce urea;
  • Urea / aw, passes into blood;
  • Breakdown of, hormones / toxins / drugs / excess vitamins;
  • Breakdown of, worn out red blood cells;
  • Excretory products put in bile; e.g. Cholesterol.

[q] What is Mechanical digestion?

[a] The breakdown of food into smaller pieces without chemical change to the food molecules by tearing is called Mechanical digestion.

• breakdown of food, into smaller pieces/to increase SA; 
• ref. to chewing / tearing /using teeth /masticating grinding;
• without chemical change to the food molecules;

[q] What are the Functions of Mouth?

[a] 

• Ingestion of food;
• Mechanical digestion by teeth; → ↑ Surface area to volume ratio.
• Chemical digestion of starch by salivary amylase.

• Mastication; formation of a bolus and lubricated in saliva; → swallowing.

[q] Name parts (the stars in diagram) of the alimentary canal:

[a]

[q] Name parts of the human teeth?

[a]

[q] What are the Functions of Pancreas?

[a] Secretes pancreatic juice into the duodenum via pancreatic duct for chemical digestion of proteins, fats and starch.

[q] What is Peristalsis?

[a] Peristalsis is

1. Circular muscles contract (to push to food);
2. Muscle contraction above food pushes it forward;
3. Circular and longitudinal muscles work antagonistically / AW;

[q] How to Prevent tooth decay?

[a] 

• Avoid eating sugary foods / eat less sugar;
• Do not eat between meals / AW;
• Brush teeth regularly;
• Use of dental floss / interdental brushes;
• Use fluoride, toothpaste / water;
  
  • However, Fluoride has a bad taste, may cause allergies and discoloured teeth.
• Calcium rich diet;
• Visit dentist;

[q] What are the Functions of Salivary glands?

[a] The Functions of Salivary glands are:

• saliva contains amylase → chemical digestion of starch in food;
• saliva contains liquid → lubricate food and make small pieces stick together.

[q] State the 4 types of Human Teeth?

[a] Incisors, Canines, Premolars, Molars.

[q] State the type of human teeth?

[a] Molar

[q] State the type of human teeth?

[a] Premolar

[q] State the type of human teeth?

[a] Incisor

[q] State the type of Human Teeth?

[a] Canine

[q] What are the Functions of Stomach?

[a] The Functions of Stomach are:

• Produces gastric juice containing:
  
  • Pepsin:
    
    
    • Chemical digestion by enzymes of molecules and bacteria
      
      • • Protein → Amino Acids
        • Hydrochloric acid:
          
        • Creates optimum pH (pH 2) for enzyme / pepsin.
          
        • Kills (harmful) microorganisms
          
• Churning / Muscular Action → ↑ Surface Area
  
• Pyloric sphincter; band of muscle → stops solid pieces of food from passing through.

[q] Explan the Structure of teeth?

[a] 

• Enamel → Hardest tissue in the body
• Dentine → Softer than enamel
• Pulp Cavities → Contains blood vessels and nerves
• Cement → Anchors tooth to the jaws
• Gums → Cover junction between enamel and cement

[q] Explain VILLI?

[a]

• The small molecules of digested food pass into the epithelial cells and then through the wall of the capillaries in the villus and into the bloodstream.
  
• Hepatic Portal Vein
  
  • Carries all the blood from the intestines to the liver
    
    • Reduce high Glucose and Amino Acid concentration before entering blood circulation.
      
• Lacteal
  
  • Fatty acids and glycerol enter the blood capillaries of the villi.
    
  • Fatty acids and glycerol combined to form fats again in the intestinal epithelium.
    
  • Fats then pass into the lacteals, and flows into the lymphatic system.
    
• Epithelial cell
  
  • One cell thick
    
  • Mitochondria for Active Transport
    
• Goblet Cell
  
  • Produce mucus to protect gut wall against enzymes, stomach acid, physical damage and toxins.

[q] What are the necessary food groups/nutrients?

• Muscles contraction
• Transmission of nerve impulses
• Blood clotting
• Formation of bones and teeth
• Prevent rickets

• Angina (chest pains when exercising or climbing stairs, for example).
  
• Coronary heart attack.

• First part of the small intestine;
• Receives pancreatic juice; consist of pancreatic amylase, trypsin, lipase and sodium hydrogencarbonate.
  
  • Chemical digestion of proteins, fats and starch as well as neutralising hydrochloric acid;
• Receives bile →
  
  • Emulsify fats (a form of physical digestion) as well as neutralising hydrochloric acid.

• Long → increased surface area to the digested food.
  
• Villi (circular folds bearing thousands of tiny projections) → greatly increase surface area.
  
• Thin epithelium lining → fluids can pass rapidly through it.
  
• Microvilli on each epithelial cell.
  
  
  • Increase by (20 times) surface area for maximum absorption by diffusion and active transport.

• Egg yolk, Liver, Fish oil.
• Made in the presence of sunlight by the skin.