Respiration Flashcards
What is the human respiratory system’s function?
Functions in the gaseous exchange of oxygen and carbon dioxide between an organism and the environment
Pathway taken by the air during inhalation
Nostrils, nasal cavity, pharynx, larynx, trachea, bronchi, bronchiole, alveoli
Where does gaseous exchange occur?
In the alveoli (singular alvelolus) of the human respiratory system
What is the makeup of inspired air?
21% O2 0.03% CO2 78% N2 Variable H20 (g) Room temp Variable dust
What is the makeup of exhaled air?
17% O2 4% CO2 78% N2 Saturated water vapour 37° Absent dust particles
Function of nasal passage
Moisten and warm inhaled air
Lined with hairs to trap dirt in inhaled air
Function of the larynx
Cartilaginous structure
Contains elastic vocal cords
Function of the trachea
Contains C-shaped rings of cartilage
Prevents trachea from collapsing
Keeps airways open
Function of bronchi (singular bronchus)
Trachea divides into 2 branches known as the bronchi (into each lung)
Function of the bronchiole
Bronchiole form from the branching of the bronchi
Function of the alveoli
Found at the ends of the bronchiole
Site of gaseous exchange in the respiratory system
What do the inner surface of the airways contain, and what are their functions?
Mucus: sticky substance produced by goblet cells in respiratory system to trap inhaled dust
Cilia: hairs on inner surface of airways that sweep mucus containing dust out of the airways
Define ventilation
Ventilation (breathing) is the exchange of air between the lungs and the environment during inhalation (breathing in) and exhalation (breathing out)
Where are the lungs located?
Within the thoracic cavity
What is air moved in and out of the lungs by?
Internal and external intercoastal muscles
Diaphragm muscles
Rib cage
What happens during inhalation? (Intercoastal muscles, rib cage, diaphragm, volume of thoracic cavity, lung pressure, air movement)
External intercoastal muscle: contract Internal intercostal muscles: relax Movement of ribcage: upwards and outwards Diaphragm: muscle contracts, flattened Volume of thoracic cavity: increases Pressure of lungs: lower than atmosphere Movement of air: forced into lungs
What happens during exhalation? (Intercoastal muscles, rib cage, diaphragm, volume of thoracic cavity, lung pressure, air movement)
External intercoastal muscle: relax
Internal intercostal muscles: contract
Movement of ribcage: downwards and inwards
Diaphragm: muscle relaxes, curves up
Volume of thoracic cavity: decreases
Pressure of lungs: higher than atmosphere
Movement of air: forced out from lungs
What is tidal volume, vital capacity and residual volume?
The volume of air inhaled and exhaled in each breath (~500 cm^3)
Vital capacity: tidal volume during maximum inhalation and exhalation (~3.4-4.8 litres)
Residual volume: volume of air that remains in the lungs after forced exhalation
What is the stimulus for breathing? Does o2 concentration have any effect?
Carbon dioxide concentration
The higher the concentration of carbon dioxide in blood, the higher the breathing rate
Oxygen concentration in blood has no effect on breathing rate
Structural adaptations of alveoli
Large numbers: total large surface area for quick gas diffusion and exchange
Alveoli and capillary walls are one cell thick: short diffusion distance allows quick gas diffusion between alveoli and blood capillary
Thin layer of moisture of the surface of alveoli: allows gases like oxygen to dissolve in and easily diffuse into the blood in the capillaries
Maintenance of a steep concentration gradient between alveoli and blood: blood constantly flowing in alveoli capillaries due to heart pumping, keeps o2 low and CO2 high in blood capillaries. Breathing keeps concentration of o2 high and CO2 low in alveoli space
What is the difference in composition of blood in the pulmonary arteriole and venule?
The pulmonary arteriole (deoxygenated) contains a lower concentration of oxygen and a higher concentration of carbon dioxide as compared to the pulmonary venule (oxygenated)
What gaseous exchange occurs at the alveolus?
Simple diffusion, oxygen molecules out and carbon dioxide molecules into the alveolus
How is carbon dioxide transported in the body?
As bicarbonate ions dissolved in blood plasma
~7% of carbon dioxide dissolved directly
~5% of bicarbonate ions bind to haemoglobin and are transported inside the erythrocyte
What is the enzyme found in red blood cells and what is its function?
Carbonic anhydrase
It catalysed a reversible reaction, where the direction of the reaction depends on the relative concentration of CO2 and water with respect to carbonic acid
