deck_1284797 Flashcards
Outline the key functions of the respiratory system
• Gas exchange - Serves to ensure that all tissues receive the oxygen they need and can dispose of CO2 they produce• Immune functions• Inhalation & exhalation• Vocalization • Metabolic and endocrine functions
Define the term upper respiratory tract
• The part of the respiratory tract above the lower border of the cricoid cartilage (which forms the lower border of the larynx) is termed upper respiratory tract.
Define the term lower respiratory tract
• The parts of the respiratory tract below the lower border of the cricoid cartilage, including the lungs and associated structures.
What are the four main structures found in the URT?
• Nose• Paranasal sinuses• Pharynx • Larynx
Describe the pulmonary circulatory system of the lungs
Low resistance system which is ‘supply driven’ rather than demand ledLow pressureeceives entire cardiac output
What is the purpose of resistance vessels in the pulmonary circulation?
• Do not influence total flow through pulmonary circulation, only distribution of blood within it
Why is tissue fluid not normally formed in the lungs?
Capillary pressure in the normal pulmonary circulation is always less than the colloid osmotic pressure
Give three main functions of the URT
• Conducting air from atmosphere to the lower respiratory tract• Conditioning (warming, humidification and trapping of particles) of inspired air• Protection of the airway during swallowing (larynx)
Give three minor functions of the URT
• Swallowing (oropharynx and laryngopharynx)• Smell (olfactory epithelium in nose)Speech (larynx)
What two main parts make up the nose?
• The external nose (bone and cartilage) • the nasal cavity
Describe the structure of the nasal cavity
• Divided into right and left cavities by the median nasal septum• Each nasal cavity extends from the nostril (anterior nares) the posterior nare (or posterior chonae) behind.
Outline the structure of the lateral wall of each nasal cavity
Contains three bony projections known as the choncae (superior, middle and inferior)• The space below each conchae is known as the meatus (superior, middle and inferior)
What structures drain into the meatus of the nasal cavity?
The paranasal sinusThe nasolacrimal duct
What does the floor of the nasal cavity form?
• The roof of the mouth
What are the three main functions of the nose?
• Respiration ○ Filters air ○ Humidifies and warms air• Organ of smell• Receives local secretion ○ Sinuses ○ Nasolacrimal duct
How does the structure of the nose relate to its function?
- Turbinates aid in warming and humidification by increasing SA and slowing airflow• Lined by coarse hairs which aid in filtering of inhaled air• Moist epithelium traps particles• Watery nasal secretions evaporate and humidify air
Aside from humidification of air, what is the function of secreted nasal mucus and associated cilia?
Mucus secreted by goblet cells traps almost all particles. Cilia waft mucus to oropharynx where it is swallowed
Name the four paranasal sinuses
The frontal, ethmoidal, maxillary and sphenoidal sinuses
Give five possible functions of paranasal sinuses
• Extension of nasal cavity (humidification and warming of inspired air)• Secrete mucus to moisten nasal chambers• Lighten weight of skull• Buffer for trauma (crumple zones)• Insulating sensitive structures from temperature variation (eye, dental roots)
What are the three parts of pharynx?
• Nasopharynx• Oropharynx• Laryngopharynx
What is the key function of the pharynx?
• Prevent aspiration of food during swallowing, which can lead to life threatening airway obstruction or infection
How is the nasopharynx connected to the middle ear cavity?
• By the auditory tube (eustachian tube)
What does the connection of the nasopharynx to the middle ear cavity allow?
• Air pressure in middle ear cavity to be equalized to atmospheric pressure
What issue can the connection of the nasopharynx to the middle ear cavity cause?
• URTI can be spread to the middle ear cavity via the auditory tube, resulting in middle ear infection. More likely in children than adults.