Introduction Flashcards
What are the 5 functions of the respiratory system?
Gas exchange Regulation of body pH Protection Vocalisation Synthesis of hormones
Where does gas exchange occur in the body?
Between the atmosphere and blood
Between the blood and tissue
Release of which molecule regulates body pH?
CO2
How does CO2 regulate body pH?
CO2 + H2O –> H2CO3
H2CO3 –> H+ + HCO3-
H+ release which can change pH levels
Why is the respiratory system needed for vocalisation?
Air flow is needed through he vocal chords to make a sound
What enzyme is synthesised in the lungs?
Angiotensin
What is external respiration?
Exchange between the atmosphere and the lungs
Gas exchange in the lung
Transport of O2/CO2 in the bloodstream
Gas exchange in the tissue
What is cellular respiration?
Chemical reactions in cells producing ATP using O2
What makes up the upper respiratory tract?
Nasal cavity, pharynx, vocal cords, larynx
What are the functions of the upper respiratory tract? (4)
The conchae warm and humidify air.
Hair cells and mucosal surfaces in the nose filter the air
Vocal cords and larynx used for vocalisation
What makes up the lower respiratory tract?
Trachea
Bronchi
Bronchioles
Alveoli
What are the functions of the lower respiratory tract? (4)
Conduct air
Stabilise conductive airways
Regulate flow
Gas exchange
What are the conductive airways?
The airways that conduct clean, warm, moist air
Nose, pharynx, larynx, trachea, bronchi, bronchioles.
No gas exchange occurs here
Describe the structure of the trachea and what is the purpose of this?
Supported by U-shaped cartilage rings, they help to protect the trachea against insult from outside and ensure it doesn’t collapse as a result of airflow through it.
Not a full ring so can expand when something large passes through it.
When are the muscles around the trachea used?
When coughing
How is the upper part of the bronchi held open?
Cartilage rings
How is the lower part of the bronchi held open?
Plates
Does the bronchi have a muscular layer?
No
What cells are found int he epithelium of the conducting airways? What is the name of this system?
Goblet cells and ciliated cells
Mucocillary escalator
What is the function of goblet cells?
Secrete mucous to form a continuous protective layer over the surface of the respiratory tract
What is the function of the ciliated cells?
Sweeps mucous upwards towards the pharynx
What is the function of the mucocillary escalator?
Removes noxious particles from the lungs
Do the bronchioles have cartilage rings? What does this mean?
No
They can collapse and become obstructed
What type of muscle lines the walls of the bronchioles?
Smooth muscle cells
How is the airway diameter of the bronchioles regulated? (4)
Gas composition (CO2) Hormones (histamine constricts the bronchioles) Parasympathetic NS (Ach acts on M3 receptors on smooth muscle cells to cause bronchoconstriction) Sympathetic NS (NA acts on beta 2 receptors on smooth muscle cells to cause bronchodilation)
What is the difference between the structure of the side of the alveoli facing the capillaries and the supporting side?
The side facing the capillaries is delicate and leaky to allow gas exchange
The supporting side is rich in collagen IV, it is robust and contains elastic fibres
What property of alveoli is essential to the function?
The elastic properties
Does the pulmonary artery conduct oxygenated or deoxygenated blood?
Deoxygenated
What is the purpose of the extensive capillary network?
Provide a large SA for gas exchange
What is shunt?
Blood from the bronchiolar artery draining directly into the pulmonary circulation to reduce O saturation
What are the 2 types of alveolar cells and their functions?
Alveolar cell type I –> gas exchange
Alveolar cell type II –> secrete surfactant which reduces surface tension and stops the alveoli from collapsing
What is the purpose of macrophages in the alveoli
They protect the alveoli from small particles and ingest degraded surfactant
What is the purpose of pores of Kohn?
Intra-alveolar ventilation
How are flow and resistance related?
Flow is inversely proportional to resistance
Why do the bronchioles have the highest resistance?
They have the smaller diameter
What does resistance depend upon? (3)
Diameter of the airways
Flow pattern (laminar or turbulent)
Viscosity of the gas
Why does resistance increase in inflamed airways or in airways with increased mucous production?
In both circumstances the diameter of the airway decreased
