7 - Exchange Surfaces and Breathing Flashcards
State 3 features of the nasal cavity that improve gas exchange
- moist
- good blood supply
- hairs and mucus
Why does good blood supply in the nasal cavity improve gas exchange?
- warms the air
- increased Ek
- greater rate of diffusion when in lungs
Why does moisture in the nasal cavity improve gas exchange?
- keeps the air moist
- can dissolve in water when diffusing out of alveloli
Why do hairs and mucus in the nasal cavity improve gas exchange?
- trap bacteria and dust
- prevents delicate lung tissue from irritation and infection
State 2 features of the trachea that improve gas exchange
- c-shaped rings of cartilage
- lined with ciliated epithelial cells and goblet cells
Why are the rings of cartilage in the trachea not full circles
Allows food to easily move down oesophagus behind the trachea
Why does the trachea have rings of cartilage?
To protect the trachea from collapsing and trauma
What do the ciliated epithelial cells and goblet cells do in the trachea?
Goblet cells, secrete mucus onto the lining of trachea to trap dust and microorganisms
Cilia beat to move mucus and the trapped artefacts away from lungs and to throat where it is swallowed and digested
State a feature of the bronchus that improves gas exchange and how it works
-rings of cartilage - provide support, strong yet flexible, prevent from collapse
State 2 features of the bronchioles that improve gas exchange
- thin layer of epithelial cells
- smooth muscle
Why do the bronchioles have smooth muscle?
Allow the lungs to constrict and dilate
Why do the bronchioles have a thin layer of epithelial cells?
Allows some gaseous exchange
State 4 features of alveoli that improve gas exchange
Thin
Good blood supply
High SA
Good ventilation
Why do alveoli have thin walls?
Short diffusion pathway
MAkes diffusion of oxygen into blood and CO2 out of blood more easy
Why do alveoli have good blood supply?
takes O2 away from lungs quickly so maintains a high conc. gradient
Why do alveoli have large SA?
Large amounts of oxygen able to diffuse into blood to meet metabolic demand
Why do alveoli have good ventilation?
Breathing moves air in and out of lungs
Helps maintain steep conc. gradients
Describe inhalation in terms of pressure
Pressure in the atmosphere is greater than the pressure in the lungs, forcing air into the alveoli
Describe exhalation in terms of pressure
Pressure in the lungs is greater than the pressure in the atmosphere, forcing air out of the alveoli
What happens to the diaphragm during inhalation
contracts and flattens
increases volume fo thorax
What happens to the diaphragm during exhalation
relaxes and curves
decreases volume of the thorax
What happens to the intercostal muscles during inhalation
external intercostal muscles contract
ribs move up and out
increases volume of the thorax
What happens to the intercostal muscles during exhalation
internal intercostal muscles contract
ribs move down and inwards
decreases volume of the thorax
What is the tidal volume of the lungs
the volume of air that moves in and out with each resting breath
What is the residual volume of the lungs
volume of air left in the lungs when one has exhaled and hard as possible
What is vital capacity of the lungs
volume of air that can be breathed in when the strongest exhale is followed by the deepest inhale
How do you calculate ventilation rate?
tidal volume x breaths per minute
Describe how a spirometer works
The patient breathes in and out of an airtight chamber filled with oxygen thus causing it to move up and down and leave a trace on the graph
Describe the structure of spiracles in the insect gaseous exchange system
found along the sides of insects
opening of larger tubes called trachea
have sphincters to control entry and exit
How will the state of spiracles change in an insect depending on metabolic demand
High metabolic demand, O2 demand is high, spiracles open to let oxygen in and CO2 out
Low metabolic demand, O2 demand low, spiracles kept closed
Describe the structure of tracheas in insect gaseous exchange system
large tubes
lined with chitin rings
Describe the structure of tracheoles in insect gaseous exchange system
single, elongated cells
no chitin so freely permeable to gas
filled with tracheal fluid
Describe how gaseous exchange occurs in insects
Low metabolic demand- a small amount of O2 can diffuse from tracheoles
High metabolic demand - cells respire anaerobically, produce lactic acid which lowers the water potential of cells. Tracheal fluid diffuses out leaving a moist exchange surface for oxygen to diffuse through
What is the difference is the gill structure of bony fish and cartilaginous fish
Bony fish- operculum to cover gills, counter-current exchange system
cartilaginous fish- open gill slits, concurrent exchange system, ram ventilation
What is the role and structure of the operculum?
Bony plate that covers the gills to protect them from damage
What do the gill rakers do?
Clean water for any dirt and bits
What does the gill arch do?
Supports the gill plates and carriers the blood supply
What are the gill plates made of? (2)
Gill filaments, each filament is made up of hundreds of microscopic lamellae, this is where gaseous exchange occurs
Describe how inhalation occurs in fish
Mouth opens
Buccal chamber expands (pressure decreases)
water flows in
Describe how exhalation occurs in fish
Mouth closes
Buccal chamber decreases in size (pressure increases)
water flows out through gills
