Respiratory System Flashcards
Breathing
The process of moving air in and out of the lungs
Respiration
Chemical reaction that occurs in cells converting oxygen into usable energy for the cell
glucose + oxygen -> carbon dioxide + water + energy
Function of the respiratory system
- take in oxygen from external environment
- pass our waste & carbon dioxide
2 Zones
Conducting zone
- nose/nasal cavity
- pharynx
- larynx
- trachea
Respiratory zone
- bronchi
- bronchioles
- alveoli
Pharynx
The soft part on the top of the throat
Also used to pass food from mouth into oesophagus
Larynx
Voice box
Nose/nasal cavity
- Filters, warms and moistens air before it enters the lungs
- Hair (cilia) and mucus trap foreign particles
Trachea
- C-shaped band of cartilage -> flexibility & support
- lined with mucus membrane & cilia -> traps solid particles
Bronchi
Contains cartilage rings and ciliated mucus membranes
Bronchioles
Fine smooth tubes (no cartilage or cilia) that pass air from bronchi to alveoli
Alveoli
- Tiny air sac found in clusters at the end of bronchioles
- site of gas exchange (O2 & CO2)
- thin walls & surrounded by blood capillaries
Intercostal muscles
- muscles between ribs
- external & internal
Diaphragm
- flat muscle under lungs
- flattens to increase chest cavity
Inspiration
Diaphragm contracts -> chest cavity extends downwards
External intercostal -> ribcage upwards & outwards
increase lung volume
decreased air pressure
Expiration
Diaphragm relaxes (expands) -> chest cavity push upwards
Internal intercostal relaxes -> rib cage downwards & inwards
decrease lung volume
increased air pressure
Gas exchange
Oxygen: alveoli -> blood
CO2: blood -> alveoli
Diffusion
Movement of particles from an area of higher concentration to an area of lower concentration until they’re equally distributed
Concentration gradient
A difference in the concentration
Needs to be maintained in body so cells can keep taking in O2
maintained by:
- continuous movement of blood in capillaries (that surround alveoli) moving oxygen away
- constant inhaling & exhaling bring in new air to diffuse
Oxygen in air
Inspired -> 20.95
Expired -> 15.8
CO2 in air
Inspired -> 0.04
Expired -> 4.3
Nitrogen in air
Inspired -> 78.09
Expired -> 78.08
Water vapour
Inspired -> variable
Expired -> saturated (a lot)
Why are the lungs suitable for it’s function
- a lot of alveoli and curved (convoluted) structure -> exchange quicker
- alveoli is covered in capillaries -> exchange quicker in shorter distance
- walls of capillaries & alveoli one cell thick -> exchange quicker in shorter distance
- surface of alveoli is covered in moisture -> gas diffuses faster when it is dissolved in liquid
