gcse science biology unit B5

Created by: charlie
Created on: 24-05-13 14:44

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B5
- lung disease
  - respiratory tract
    - bronchi
      - lined mucus and cilia
        trachea
        
        cilia beat pushing microbe mucus out as phlegm
        
        sometimes get past defence and infection
    - trachea
  - prone to infection as dead end
  - caused by
    - industrial materials
      - asbestos
        inflammation and scarring limits gas exchange
    - genetic
      - cystic fibrosis
        thick sticky mucus clogs up bronchioles
    - lifestyle
      - smoking
        cells divide and tumour reduces SA
    - asthma
      - over sensitive lungs
        muscles contract constrict airways
- digestion
  - big molecules
    - smaller molecules
      - blood plasma/lymph
  - physical digestion
    - provides large SA for chemical
  - chemical digestion
    - enzymes catalyse and break down big molecules
  - carbohydrases
    - starch to maltose to glucose
    - mouth and small intestine
  - proteases
    - proteins to amino acids
    - stomach and small intestine
  - lipases
    - fats to fatty acids and glycerol
      - lymph
        lymphatic system
        blood
    - small intestine
      - adapted
        long- for time
        
        villi projections - large SA
        micro villi- SA
        
        single permeable surface cells
  - right conditions
    - stomach-acidic
    - mouth, s. intestine- alkaline
  - bile
    - made (liver) stored (gall bladder)
    - improves fat digestion
    - emulsification
      - small droplets
        bigger SA
    - alkaline
      - neutralises before s.intestine
- the kidneys
  - functions
    - remove urea
    - adjust salt levels and blood water
  - blood filtered through nephrons
    - ultrafiltration
      - high pressure forces U,S,W,G into capsules
        membranes between blood vessels glomerus and capsules filter
        big molecules- protein, red BC stay in blood
    - reabsorbtion
      - useful substances
        all sugar by active transport
      - sufficient salt and water according to ADH hormone
    - released waste
      - urine into ureter
        bladder
- waste removal
  - controlled by kidneys
    - anti-diuretic hormone (ADH)
      - controlled by pituitary gland to release
        negative feedback
        ADH released when water loss detected
      - amount of urine depends on
        heat
        sweat= water loss
        
        exercise
        sweat= water loss
        
        water
        no drinking= concentrated
  - dialysis
    - regular
    - fluid acts like blood plasma
    - waste products diffuse out
      - selectively permeable membrane
        dialysis fluid in
        takes in waste products
    - same concen, of sodium and glucose
      - not lost from blood
- menstrual cycle
  - start- uterus lining breaks down
    - 4-14- builds up again
      - 14- ovulation- egg released
        14-28- if no egg fertilised spongy lining breaks and cycle starts
  - controlled by 4 hormones
    - FSH
      - pituitary gland
        egg develop in one ovary
        
        stim. ovaries produce oestrogen
    - oestrogen
      - ovaries
        uterus lining repairs
        
        stim. LH release of egg and inhibits FSH
    - LH
      - pituitary gland
        stim. release of egg day 14
        
        indirect stim. progesterone
    - progesterone
      - ovaries
        maintains lining, levels fall so does lining
        
        inhibits LH
  - negative feedback affect controls hormones
    - one concen too high- another released
- controlling fertility
  - contraceptive pill
    - oestrogen
      - mimics pregnancy
      - inhibits FSH
  - infertility treatments
    - artificial insemination
      - sperm injected to uterus
    - FSH injections
      - stimulate egg production
    - In Vitro Fertilisation
      - fertilised outside body
        hormones to stimulate egg production
        collected and mixed with sperm
        need- sperm, eggs, healthy uterus
      - unused eggs thrown away
      - inc. chance of multiple pregnancy- damage mothers health
    - Ovary Transplants
  - screening foetuses
    - amniocentesis
      - fluid surrounding taken out and analysed
        if genetic defect parents question
        
        increase risk of miscarriage
- growth influences
  - diet- proteins+minerals
  - exercise- stimulates HGH- stimulates long bone growth
  - hormones/ genetics- giantism
- people live longer than used to
  - medicine, safer, diet, less disease

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gcse science biology unit B5

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