Exchange: Summary notes

My summary notes from last year on exchange

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  • Created by: sxrcha
  • Created on: 17-10-15 14:33
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Chapter 4
Exchange ­ Summary Notes
Exchange Surfaces
Large organism = large surface area and volume
Volume increases more than SA
Must have:
Large surface area ­ for gas exchange
Thin ­ shorter diffusion distance
Diffusion gradient ­ substances move down gradient
Moist ­ cells don't dry out
Emphysema ­ alveolar walls break down ­ often caused by smoking
Exchange
Thorax = chest
Pleural membrane ­ surrounds lungs ­ secretes pleural fluid
Trachea bronchus bronchiole alveolus
Alveoli ­ surrounded by capillaries
Lungs ­ no muscle ­ movement from diaphragm
Intercostal muscles ­ between ribs
Rib cage ­ protects lungs and heart
Airways ­ lined with epithelial tissue ­ ciliated cells, goblet cells
Basement membrane ­ contains p rotein fibres
­ cells below secrete p roteins
Cilia ­ microtubules slide past each other ­ c ilia bend
Goblet cells ­ between ciliated cells ­ secrete m ucus
Mucus:
Contains glycoprotein ­ long chains of s ugar molecules
Protective cover on epithelium ­ stops drying
Airways contain cartilage, smooth muscle and elastic tissue
Cartilage:
Tough tissue
Supports walls of trachea, bronchi
Cshaped rings in trachea
Smooth muscle:
In walls of trachea, bronchi , bronchioles
Contracts slowly
Involuntary
Narrows airways
Made wider when exercising
Asthma ­ smooth muscle contracts in response to harmless particles in air
Elastic fibres:
In walls of airways
Around alveoli
Inspiration ­ alveoli expand ­ fibres stretch
Expiration ­ fibres recoil ­ force air out

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Chapter 4
Alveoli:
Air spaces
divided by thin walls
Surrounded by capillaries
Elastic fibres ­ strength
and flexibility
Macrophages:
Patrol alveolar surfaces
Phagocytes
Engulf and digest harmful materials
Some can't be digested ­ a sbestos
Breathing
Movements that cause air to enter and leave lungs
Movement ­ caused by diaphragm and intercostal muscles
Inhalation:
External intercostal muscles contract
Ribs move up a nd out
Diaphragm contracts ­ moves down
Increased volume = decreased pressure
Air drawn in ­ pressure gradient
Exhalation:
Elastic fibres recoil
Diaphragm…read more

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