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05 A táplálkozás és a légzés

2014.04.09

 

Nutrition and breathing
 
Why do we use food?
                     For energy
                     For growth and repair
                     For chemical reactions
What is in our food?
                     Proteins
                     Carbohydrates
                     Fats
                     Water
                     Vitamins
                     Minerals
                     Fibre
Vitamins and minerals
We need small, regular amounts of them
They are essential for good health
Deficiency diseases: are caused when you have no enough of a certain vitamin or mineral
         Vitamin A: poor night vision
         Vitamin B1: beri-beri
         Vitamin D: soft bones
         Vitamin C: scurvy
Digestion - absorption
                     Digestion: breaking down of large insoluble molecules
                     Absorption: passing of small soluble food molecules into the blood across the gut wall
 
Structure of the digestive system
Fore-gut
Oral cavity
Lips: sphincter
Teeth: grinding of food, speech
                     Structure: crown, neck, root, enamel, dentine – cementum, pulp (blood vessels, nerves)
                     Types: incisor, canine, premolar, molar
Hard palate
Soft palate – uvula
Tongue: feels tastes (taste buds), mixing, rolls the food into small ball and pushes back
Saliva:
·         Is made in salivary glands
·         Amylase breaks down starch
·         Mucus: slimy substance, helps food to slip down
Pharynx
                     Epiglottis: covers the opening of the trachea
Esophagus: circular muscles in its wall (upper part: skeletal, lower part: smooth muscle tissue)
·         Contract behind and squeeze in behind food ball and push it along (PERISTALSIS)
Stomach: muscular bag, holds up to 2 litres of food
                     Stores, mixes and digests the food
                     Produces gastric juice:
                                            Protease (pepsin): breaks down proteins to amino acids
                                            Hydrochloric acid:
                                                                     Pepsin needs acidic pH
                                                                     Kills germs
                     Rennin: in babies makes milk solid and it can be digested
                     Muscular walls: churn up the food for 2-3 hours (mixing up well with digestive juices)
Mid-gut (small intestine)
Duodenum:
Bile
                     Is made by the liver
                     Stored in the gall bladder
                     Enters the small intestine from the bile duct
                                            It is alkaline, neutralises asids, gives the best pH for the enzymes
                                            Emulsifies fats (large drops to small ones)
Pacreas: produces pancreatic juice:
                     Contains proteases, lipases, carbohydrases and nucleases
Intestinal juice: is made by glands in the wall of the small intestine
                     Contains protease, lipase, carbohydrase, nuclease
                     These enzymes complete the digestion of the food
Digested food passes through the gut wall
It is helped by
                     A thin lining
                     A good blood supply
                     A very large surface area (200 m2)
                                            Length about 6 metres
                                            Folded inner lining
                                            Millions of villi and microvilli (singular: villus)
Hind-gut
Large intestine
Caecum: appendix (immune system)
Colon
Food contains only
                     Fibre
                     Dead cells
                     Water
                     Bacteria (produce B and K vitamins)
Water absorption
Faeces are stored in the rectum and egested through the anus
Why is fibre important?
                     Adds bulk to food: muscles of the gut can move food with it
                     Absorbs poisonous wastes from digesting foods
                     It prevents constipation
                     High-fibre diet lowers the level of cholesterol in the blood
Health of nutrition
Dental decay/caries: acids (produced by bacteria) dissolve the salts of the enamel
Food poisoning:
                     Caused by microbes and/or toxins
                     Symptoms: nausea, vomiting, diarrhea
Parasitic worms: tapeworm, Ascaris
Transmittable diseases: dysentery, typhoid fever
 
 
Breathing
                     Glucose + oxygen = carbon dioxide + water + ENERGY
                     C6H12O6 + 6O2 = 6CO2 + 6H2O + E (38 mole of ATP, 1140 kJ)
                     We need O2: aerobic respiration
Air passageways
Nostrils
Nasal cavity: air is
                     Warmed
                     Moistened
                     Filtered and cleaned (hairs, mucus, cilia)
Mucus, slime: dust and germs get trapped in it
Cilia: beat to carry the mucus up to the nose and throat
Olfactory epithelium: smelling
Pharynx: cross of ways (food and air)
Larynx:
                     It is made of cartilage
                     Epiglottis covers its opening when you swallow
                     Vocal cords
Trachea, bronchi
                     Built up of C-shaped cartilage rings
                     It does not collapse
                     It branches many times in your lungs (like roots): bronchi (they enter the lungs), bronchioles
                     Ends up at alveoli (sing. alveolus) (tiny sacks, where gas exchange happens)
Lungs
                     They are spongy
                     Are surrounded by pleural membrane: two paralel membranes, slippery fluid between them
Ribs:
                     Protect your lungs
                     Moves during breathing
Intercostal muscles and diaphragm work during breathing
Alveoli:
                     Surrounded by capillar network
                     Thin wall
                     Gas exchange
Breathing in
                     Intercostal muscles contract, raise ribs move upwards and outwards
                     Muscle of diaphragm contracts, diaphragm flattens
                     Volume increases, pressure decreases
                     Air passes in (external pressure is greater)
Breathing out
                     Intercostal muscles relax, lower ribs move downwards and inwards
                     Muscle of diaphragm relaxes, diaphragm bulges upwards
                     Volume decreases, pressure increases
                     Air passes out (internal pressure is greater)
Breathing types
Chest breathing: rib musles are used (women, children, small mammals)
Abdominal breathing: diaphragm is used (men and other large hooved mammals)
Take a deep breath
                     Normal breath in (tidal volume): 0,5 l
                     Total breath in (inspiratory reserve volume): 3 l
                     Total breath out (expiratory reserve volume): 1 l
                     Vital (total) capacity (total breath in – total breath out): 4 l
                     Residual air: 1,5 l
Rate of breathing: 16/min
Tidal volume per minute: 8 litre
Health of breathing
„Having cold”: viral or bacterial infection
Influenza: caused by virus, fever, pains
Sinusitis: inflammation of the facial cavity
Tonsillitis: fever, pain, removing by surgery
Bronchitis: fever, severe coughing, mucus is produced and coughed up
Emphysema: alveoli are damaged (fusion), surface area decreases (smoking!)
Pneumonia: infection, alveoli filled with fluid, fever, caughing
Asthma: allergic reaction, bronchioles in spasm,
Pneumothorax: pleural membrane is harmed, lung collapses
Lung cancer: tumor in the lung tissues (smoking!)
Tuberculosis: bacteria destroy the lung tissues (screening test, vaccination