Human nutrition

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Human nutrition by Mind Map: Human nutrition

1. 7.4 Chemical digestion

1.1. significance

1.1.1. to produce small soluble molecules that can be absorbed

1.2. Function of enzymes

1.2.1. Fats Bile Fat droplets and triglyceride

1.2.2. Proteins enzyme: Protease Polypeptides

1.2.3. Carbohydrates (starch) enzyme: amylase product: maltose

1.3. Where enzymes (amylase, protease, lipase) are secreted

1.3.1. amylase where enzymes come from salivary glands pancreas

1.3.2. lipase where enzyme comes from pancreas

1.3.3. protease pepsin where enzyme comes from trypsine where enzyme comes from

1.4. where carbohydrates, proteins and fats are broken down

1.4.1. mouth complex carbohydrates polysaccharides ->salivary amylase ->disaccharides

1.4.2. stomach proteins proteins->pepsin->small polypeptides

1.4.3. small intestine proteins smaller peptides->proteases(trypsin and chymotrypsin)->peptides->peptidases->amino acids complex carbohydrates polysaccharides and disaccharides->carbohydrates (pancreatic amylase, sucrase, maltase, and lactase)->monosaccharides fats fat droplets->bile->fat droplets (emulsified)->lipase->glycerol and fatty acids

1.5. digestion of carbohydrates on brush border

1.5.1. amylase is secreted into alimentary canal and breaks down starch to maltose

1.5.2. maltose is broken down by maltase to glucose on the membranes of epithelium lining of small intestine

1.5.3. enzymes (sucrase, maltase, lactase) are attached to lining of small intestine

1.6. Functions of hydrochloric acid in gastric juice

1.6.1. 1. kills bacteria in ingested food (e.g. denatures enzymes bacteria make)

1.6.2. 2. gives acidic pH for optimal enzyme activity (of pepsin)

1.6.3. 3. denatures ingested proteins (unfolding) so they are easier to digest

1.6.4. 4. inactivates amylase in ingested food (and food)

1.7. Functions of bile

1.7.1. 1. alkaline substance that neutralises acidic chyme (when it enters small intestine)

1.7.2. 2. gives alkaline pH to small intestine (so that it is optimal for enzyme action)

1.7.3. role in emulsifying fats- 3. breaks up fats to small droplets (mech. digestion) and 4. increases surface area of fats for chem. digestion by lipase

2. 7.5 Absorption

2.1. small intestine is region for absorption of digested food

2.2. How is small intestine adapted for food absorption?

2.2.1. VILLI- increases surface area

2.2.2. LACTEAL- absorbs fats and sends them to lymphatic system

2.2.3. NETWORK OF CAPILLARIES- maintains steep concentration gradient between lumen and villi

2.2.4. MICROVILLI- on border of villi increases internal surface area of small intestine

2.2.5. WALLS OF VILLI- (1 cell thick) shortens diffusion distance b/w lumen and villi

2.3. why is small intestine the longest section of alimentary canal?

2.3.1. 1. allows enzymes to act on macromolecules

2.3.2. 2. allows large surface area for absorption

2.4. Villus

2.4.1. covers walls of small intestine

2.4.2. features 1. covered with cells of one cell thick 2. each has microvilli and 3.enzymes to complete digestion of proteins, fats and carbs has 4.blood capillaries to absorb glucose, amino acids, water, vitamins and minerals by diffusion/active transport 5.lacteals absorb fatty acids and glycerol (by diffusion)

2.5. Assimilation

2.5.1. LIVER is vital in assimilation 1. excess glucose molecules absorbed in blood from small intestine go to liver- they are converted to glycogen for long term energy storage or energy through respiration 2. excess amino acids cannot be stored in body so: -liver converts them to other amino acids the body uses -removes nitrogen containing part of amino acids to form urea(excreted through kidneys), and converts remainder to energy for liver

2.6. Booklet questions

2.6.1. blood flows to the liver after the small intestine

2.6.2. capillaries inside a villi flow from arteries to veins

2.6.3. there is higher concentration of CO2 and nutrients e.g. glucose in vein than artery

2.6.4. there is lower concentration of oxygen in vein than in artery

3. 7.2 Alimentary Canal

3.1. Process

3.1.1. Ingestion: taking of substances e.g. food and drink into body through mouth

3.1.2. Mechanical digestion: breakdown of food to smaller pieces without chemical change to food molecules

3.1.3. Chemical digestion: breakdown of large, insoluble molecules into small soluble digestion

3.1.4. Absorption: movement of small food molecules through wall of intestine into blood

3.1.5. Assimilation: movement of digested food molecules into cells of body where they are used, becoming parts of cells

3.1.6. Egestion: passing out of food not digested/absorbed as faeces through the anus

3.2. Cholera

3.2.1. leads to dehydration, diarrhoea, death due to loss of water and salts Diarrhoea the loss of watery faeces (body's ability to absorb water is failing) Treatment for diarrhoea

3.2.2. How cholera causes diarrhoea, dehydration and loss of salts 1. cholera is caused by bacterium 2. bacterium is transmitted in polluted water 3. bacterium produces toxin that affects small intestine 4. toxin causes chloride and sodium ions to move into lumen of small intestine, changing water potential between lumen and cells of small intestine 5. water moves to lumen by osmosis due to high water potential in cells of small intestine 6. causes diarrhoea and dehydration

3.2.3. How can we prevent cholera boil contaminated water

3.3. Organs

3.3.1. mouth -ingestion, chem. digestion, mech. digestion digestion begins mechanical digestion by chewing to increase surface area of foods food mixes saliva for chemical digestion mucus in saliva lubricates food

3.3.2. salivary glands -chem. digestion produces saliva (amylase breaks starch to maltose)

3.3.3. oesophagus muscular tube moves bolus to stomach (by sphincter)

3.3.4. stomach -mech. digestion, chem. digestion 1. mechanically digests food by churning 2. produces hydrochloric acid -kills bacteria -maintains opt pH for function of proteases (produced in stomach) to digest proteins 3. generates chyme (food+stomach acid+enzymes)

3.3.5. duodenum (small intestine) -chem. digestion 1. where food mixes with digestive enzymes and bile 2. receives pancreatic juice (contains sodium bicarbonate that neutralises stomach acid) 3. receives protease, lipase, amylase for chemical digestion of proteins, fats, starch amylase breaks starch to maltose, then amylase catalyses breakdown of maltose to glucose 4. receives bile from liver/gall bladder that emulsifies fats to facilitate chemical digestion by lipase 5. cells covering villi (brush border) produce protease, lipase and maltase for digestion of fats

3.3.6. ileum (small intestine) -absorption, chem. digestion place where digested foods, salts, vitamins, minerals and most water are absorbed by villi to blood and lymph where fats are absorbed through lacteal in villi

3.3.7. pancreas -chem. digestion produces hormones to regulate blood sugar produces pancreatic juice contains digestive enzymes and sodium bicarbonate

3.3.8. liver -assimilation, chem. digestion produces bile assimilates digested food converts glucose to glycogen, metabolising excess amino acids for energy

3.3.9. gall bladder -chem. digestion stores excess bile before releasing it to duodenum

3.3.10. colon (large intestine) -absorption where water and salts are reabsorbed from indigested food where specific vitamins are absorbed

3.3.11. rectum (large intestine) -egestion faeces compacted and stored

3.3.12. anus (large intestine) -egestion faeces leave alimentary canal

4. 7.1 Diet

4.1. Balanced diet

4.1.1. definition: diet that provides correct amounts of nutrients to keep a person healthy

4.2. Uses of nutrients in the body

4.2.1. Carbohydrates: short term energy (rice, potato, pasta)

4.2.2. Fats: insulation, long term energy (butter, nuts, egg yolk)

4.2.3. Proteins: building muscles (growth) (meat, fish, eggs, nuts cheese)

4.2.4. Fibre (roughage): adds bulk to undigested foods, helps bowel movements (beans, fruits, veg, grains)

4.2.5. Water: main component of blood, makes up cytoplasm of cells, solvent (water, fruits, veg)

4.2.6. Vitamins

4.2.7. Vitamin C: for making collagon, for tissue repair (citrus fruits, leafy veg)

4.2.8. Vitamin D: helps calcium absorption (cheese, egg yolk, fortified foods such as milk, sunlight)

4.2.9. Minerals

4.2.10. Iron: for making haemoglobin (red meat, dark leafy veg, liver)

4.2.11. Calcium: for making bones and teeth, blood clotting (dairy products)

4.3. Pregnancy and breastfeeding

4.3.1. woman needs additional calories (additional proteins, vitamins and minerals) in diet to support growth of fetus to maintain health to supper proper milk production during breastfeeding

4.4. factors that affect dietary needs of humans

4.4.1. 1. Age- older ppl take in less calories as metabolism DECREASES + LESS exercise

4.4.2. 2. Gender- Man (physically stronger, higher body mass, more muscles -> more energy demand) Woman (less muscles, lower body mass->less energy demand)

4.4.3. 3. Activity- teenagers (boy and girl) need more energy for growth + more exercise-> more energy demand

4.4.4. 4. occupation -builder/athlete vs. IT worker

4.5. Malnutrition

4.5.1. refers to excesses or imbalances in a person's intake of energy

4.5.2. relates to starvation when we consume no food for a long time constipation condition when stool becomes hard, dry and difficult to pass, bowel movements occur irregularly scurvy obesity excess amount of body fat-leads to excess body weight coronary heart disease

4.5.3. undernutrition stunting wasting underweight cause micronutrient deficiencies/insufficiencies

4.5.4. overnutrition overweight and obesity diet related non communication diseases (ie. heart disease, stroke, diabetes)

4.5.5. Protein energy malnutrition definition: reflects lack of protein and energy intake (i.e. carbs, fats) in diet commonly affecting young children Disease: Kwashiorkor cause: lack of protein (protein helps regulate movement of water in stomach disease specific effects: swollen abdomen, discoloured hair and skin Marasmus cause: general lack of nutrients disease specific effects: emaciated (thin and weak) common effects: underweight, impaired growth

4.5.6. Vitamin D deficiency

4.5.7. causes: inadequate exposure to sunlight, imbalanced diet

4.5.8. effects: rickets (risisting in soft bones or skeletal deformities)

4.5.9. iron deficiency

4.5.10. causes: imbalanced diet, pregnancy, increased blood loss, poor iron absorption

4.5.11. effects: anemia (fatigue, impaired mental and physical function)

5. 7.3 Mechanical digestion

5.1. Types of teeth

5.1.1. 1. incisor (8 incl. upper and lower jaw): with sharp edge (biting, cutting, chopping food)

5.1.2. 2. canine (4): sharp and pointed for cutting and tearing

5.1.3. 3. premolar (8): for crushing, grinding and some tearing of food

5.1.4. 4. molar (12): for grinding and mashing food, has 4 cusps

5.1.5. milk teeth: 20

5.1.6. permanent teeth: 32

5.2. Structure of teeth

5.2.1. Enamel: non living, covers crown, hard mineralises (calcium) that protects dentine , provides biting surface, can be dissolved in acids

5.2.2. Dentine: hard but softer than enamel, mineralised, bonelike, living , surrounds pulp, contains channels with living cytoplasm, affects tooth colour, supports enamel

5.2.3. Pulp cavity: soft tissue, has nerves and blood vessels, blood supply provides food and oxygen to dentine Nerves: delivers signals in response to stimuli

5.2.4. cement: thin, bonelike, covers root, with fibres growing out that attach tooth to jawbone

5.2.5. gum: soft tissue, protects roots of teeth and jawbone

5.3. Why dental decay happens

5.3.1. 1. mouth contains bacteria

5.3.2. 2. some bacteria and other particles form plaque over teeth

5.3.3. 3. when sugary foods are eaten and not removed, bacteria in plaque feeds on sugars and use as respiration (produce acids)

5.3.4. 4. acids dissolve enamel and then dentine to form a hole

5.4. Prevention of tooth decay

5.4.1. 1. diet-eat a balanced diet, less sugar, more minerals and vitamins

5.4.2. 2. fluoride- helps build enamel, contains mineral calcium, helps neutralise acids in mouth

5.4.3. 3. brushing teeth- brush away sugars , contains fluoride which removes plaque

5.4.4. 4. floss to remove plaque (daily)

5.4.5. 5. antiseptic mouthwash- contains alcohol that kills bacteria

5.4.6. 6. dentist- fix and identify cavities, cleans plaque

5.5. Mechanical digestion (ways that happen in the digestive process

5.5.1. 1. teeth (chewing)

5.5.2. 2. stomach (churning)

5.5.3. 3. small intestine (segmentation in alimentary canal, muscular contractions)

5.5.4. 4. small intestine (emulsification)