27 - upper respiratory system Flashcards
(26 cards)
what happens during inhalation and exhalation?
during inhalation air containing oxygen passes through the nose and mouth to the lungs.
during exhalation, air containing carbon dioxide and other waste, passes out the same path.
what is external respiration?
In the lungs oxygen travels from tiny air sacs called alveoli into the bloodstream. At the same time carbon dioxide travels from the bloodstream into the alveoli for elimination.
This process of gas exchange between the lungs and the blood is called external respiration
what is internal respiration?
internal respiration exchanges gases between the blood and the body’s cells.
what do the structures of the respiratory system do?
support pulmonary ventilation, external and internal respiration, olfaction and phonation.
what happens during pulmonary ventilation
during pulmonary ventilation, or breathing, air is inhaled and exhaled. air moves in through the nasal and oral cavities, through the pharynx, larynx and trachea into the lungs, then moves back out again.
what happens during external respiration?
gases are exchanged between the lungs and bloodstream. oxygen from inhaled air moves into the pulmonary vessels, and carbon dioxide moves out on exhalation.
what happens during internal respiration?
gasses are exchanged between the bloodstream and the body tissues. oxygen carried by arteries moves into cells, and waste carbon dioxide moves out into veins.
what does the upper respiratory system consist of?
the nasal cavity, pharynx and larynx.
explain the nasal cavity
air entering the nasal cavity flows through passages created by the superior, middle and inferior nasal conchae.
explain the nasal septum
the nasal septum is the perpendicular plate of the ethmoid, septal cartilage, vomer and hard palate of the maxilla. the structures of the nasal septum separate the nasal cavity into right and left sections.
what do the bones f the nasal cavity do?
the bones of the nasal cavity form a framework that supports the nose.
what do the nasal cartilages do?
they make up the flexible cartilaginous framework of the nose.
what is the function of the upper respiratory tract?
during inhalation, air passing through the nose is filtered and warmed. inhaled air passes through the pharynx and larynx and into the trachea.
what is the nasal mucosa?
air that enters the nose is flittered, moistened, and warmed by structures in the respiratory mucosa.
the filtered, moistened and warmed air then continues towards the trachea.
what do the structures within the respiratory mucosa do?
- coarse hairs filter out large dust particles.
- seromucous glands secrete antimicrobial substances and mucus that traps and moistens the air.
- blood flowing through capillaries in the mucosa warms the air.
how is air entering the nasal cavity filtered?
by mucus and coarse hairs, then warmed and moistened.
filtered air continues through the pharynx and larynx into the trachea.
what happens after mucus in the nasal cavity and lower respiratory system traps foreign particles?
they are moved towards the pharynx. from there, the particles are swallowed through the oesophagus and destroyed in the stomach or expelled through the pharynx and oral cavity, removing them from the respiratory system.
what is sneezing?
sneezing is an involuntary expiration of air to rid the nasal passages of foreign material.
how is sneezing triggered?
particles that enter the nostrils and irritate nerve endings in the nasal mucosa trigger impulses that are transmitted via the fifth cranial nerve to the brains sneezing centre in the medulla. this sets off a respiratory response:
- rapid inspiration fills the lungs
- the epiglottis and vocal cords close
- and the muscles of exhalation in the chest and abdomen tighten in a spasmodic contraction.
these events create a buildup of pressure in the lungs. when a sufficiently high level of pressure is attained, the vocal cords relax, the epiglottis opens, and an expulsion of air rushes through the nose and mouth. the force of the sneeze propels the irritants out of the nasal cavity.
describe olfaction (smelling)
the process of olfaction, or smelling, begins with hair-like cilia that line the nasal cavity. this lining is called the olfactory epithelium.
As air enters the nasal cavity, some chemicals in the air bind to and activate nervous system receptors on the cilia.
This stimulus sends a signal to the first-order neurons connected to the epithelial cells.
The signal is carried by these neurons from the nasal cavity through openings in the ethmoid bone, and then to the olfactory bulbs of the brain.
The signals then move from the olfactory nerves (CN I) to the olfactory area of the cerebral cortex.
what are the olfaction structures?
Neurons carry olfactory signals through the cribriform plate of the ethmoid to the olfactory bulbs. From there, the signals move along the olfactory tracts to the cerebral cortex.
what is the pharynx?
The pharynx is a Musculo-membranous tube that functions as part of the alimentary canal and as an airway in the upper respiratory system
what are the three regions of the pharynx?
The three regions of the pharynx are the nasopharynx, the oropharynx, and the laryngopharynx. The oropharynx and laryngopharynx are also digestive system structures and connected to the oral cavity and oesophagus.
what is the function of the epiglottis?
Inhaled air and ingested nutrients both pass through the oropharynx behind the oral cavity. A cartilaginous structure called the epiglottis directs food and flid away from the trachea and into the oesophagus preventing inhalation of this material. The stem of the epiglottis attaches to the anterior rim of the thyroid cartilage. The superior portion of the epiglottis moves freely, and can swing up or down, like a trap door. With each swallow, the larynx rises and the epiglottis folds down over the laryngeal opening, closing off the airway. If particles make their way into the trachea, the cough reflex pushes air forcefully up through the larynx, forcing the particles back up and out.
