Respiratory system Flashcards
Function of the respiratory system
Major function - supply oxygen to body and remove CO2
Phonation (voice production)
Assist with body temperature control
Regulation of acid-base balance
Sense of smell (olfactory sense)
Respiration occurs on three levels in the body
External
Internal
Cellular respiration
External respiration
The physical act of getting oxygen in and carbon dioxide out of the body
Internal respiration
The exchange of oxygen and carbon dioxide between the blood and the cell
Cellular respiration
Which involves the production of ATP by the cell
Upper respiratory tract contains
Nose, nasal cavity, nasal sinuses, pharynx, larynx and trachea
The external structure of the nose contain
External Nares or Nostrils.
Supported by nasal cartilages
Opened by muscles
Dilated nostrils are a sign of
are a sign that the animal is having trouble getting enough oxygen for its metabolic needs
The nose is lined with
hair to filter larger air-borne particles
The skin surrounding the nostril
is continuous with, and forms part of, the muzzle
Covered with hair and contains sebaceous and sweat glands.
More rigid in rooting animals
Function of the nose
Functions to warm, humidify, and filter air before it reaches the lungs
Highly vascular, so any trauma causes significant hemorrhage
Sneezing and coughing results when inflammation and debris irritate the sensitive mucosa
Expels harmful substances
Nasal cavity is
Separated from the mouth by the hard and soft palates
Nasal Conchae or Turbinates - bony scrolls lined with mucous membranes
Nasal conchae or Turbinates
Protect against noxious gasses and trap particles.
Numerous blood vessels below mucous membrane help warm the inspired air.
Layer of mucus
Naso lacrimal ductus
Drain excess tears from the eyes into the nasal cavity
Median Nasal Septum
Separates the nasal cavity into right and left halves
Nasal meatus
pathways between the conchae or turbinates
Ventral Nasal Meatus runs just dorsal to the hard palate.
Route for passing a stomach tube
Route for passing a stomach tube
Tube is directed medially
and ventrally through the ventral nasal meatus to the nasopharynx
Very vascular area: if the
tube is not manipulated gently, bleeding will occur
paranasal Sinuses
All domestic species have maxillary, frontal, sphenoid, and palatine sinuses
Sinuses are bilaterally symmetrical, mucous membrane lined and air-filled
Reduce weight of skull
Clinically, they are infection prone
Important in dentistry of the horse, dog and cat and in dehorning in cattle
Pharynx
The common passageway that connects the:
Oral cavity with the esophagus =
OROPHARYNX
Nasal cavity with the larynx = NASOPHARYNX
A common passageway for both food and air
Openings into the pharynx are - the mouth, 2 caudal nares, 2 eustachian (auditory) tubes, esophagus, and larynx
Nasopharynx
Floor is formed by the soft palate
Openings of auditory tubes:
Connect middle ear to nasopharynx
Equalize pressure on both sides of ear drum
Laryngopharynx
Common to both digestive and respiratory passages
Inspired air passes through the nasal cavity and enters the caudal nares
Passes through the pharynx to enter the larynx (voice box)
Food enters from the mouth, passes through the pharynx, and is forced into the esophagus by contractions of the pharyngeal muscles
Larynx is closed by the epiglottis.
Swallowing involves a complex series of actions
Stopping breathing
Covering the opening into the larynx (the glottis)
Moving the material to the rear of the pharynx
Opening the esophagus
Moving the material DORSALLY into the esophagus
Larynx are joined to the pharynx by
The voice box
Mucosa-lined, cartilaginous tube
joining the pharynx to the trachea
Larynx functions
Directs air to the trachea
Prevents the aspiration of ingesta
Houses the vocal organs
Made of segments of cartilage connected to each other and surrounded by muscles
Larynx is
Larynx is supported by the hyoid apparatus
Very delicate structure – need to be gentle when intubating and extubating animals
** Cats are very prone to laryngospasm
The pattern and number of laryngeal cartilages varies among species
Major cartilages of the larynx
Epiglottis
Arytenoid cartilages (paired)
Thyroid cartilage (adam’s apple)
Cricoid cartilage
The epiglottis
The epiglottis is leaf-shaped and is located rostrally
Projects forward from the ventral portion of the larynx
Tip is usually tucked up dorsal to the caudal rim of the soft palate while the animal is breathing
What is the function of the larynx while swallowing
Epiglottis is pulled back to cover the opening of the larynx (the glottis),
Prevents the swallowed material from entering the larynx
Arytenoid cartilages attach
The vocal folds
The thyroid cartilage in the larynx
Articulates with the hyoid apparatus
Attaches muscles associated with swallowing and phonation
Cricoid Cartilage in the larynx
Connects the thyroid cartilage to the trachea
Maintains the shape of the larynx so air may pass through
Vocal folds
The laryngeal cavity - contains the vocal folds which run from the arytenoid cartilages to the interior floor of the thyroid cartilage
What forms the glottis
Arytenoid cartilage and the vocal cords form the boundaries of the glottis (opening into the larynx)
The three main functions of the larynx
Voice production
Prevention of aspiration of foreign bodies
Control of airflow to and from the lungs
Voice production of the larynx
Causes phonation by relaxing and tightening the vocal cords as air pass over them causing them to vibrate
The pitch can be changed from a low pitch (relaxed vocal cords – open glottis) to a high pitch (tightened vocal cords – closed glottis)
Prevention if aspiration of foreign bodies larynx
Mainly through the trapdoor effect of epiglottis and muscle contractions which pull entire larynx forward and fold the epiglottis back over its opening
Backed up by vocal folds
Can meet in the midline to close the glottis
Control of airflow to and from the lungs larynx
By adjusting the size of the glottis with the vocal folds and by closing the glottis with the epiglottis
Trachea divides into two main bronchi at the
Tracheal Bifurcation or Carina
Occurs at about the level of the heart
Trachea is composed of
Trachea is composed of C-shaped hyaline cartilage with the opening of the “C” dorsal
Prevents the trachea from collapsing on inspiration
Allows the trachea to change in size
Trachea is lined with
Trachea is lined with pseudostratified ciliated mucosa, like the nasal passages
Works to trap foreign bodies
Trapped material is moved cranially towards the pharynx where it is swallowed
Trachea and mucous
Mucous helps trap foreign bodies
If there is large amount of dust in the air then an increased amount of mucus is produced
Accumulates and irritates the lining of the trachea
Stimulates coughing which clears the passageway
Lower resp tract
Starts with the bronchi and ends with the alveoli
Includes all the air passages in between
All the structures of the lower portion of the respiratory tract are located in the lungs
Bronchial tree
Air passages from bronchi to alveoli are collectively called the bronchial tree because the divide into smaller and smaller branches, just like a tree
Bronchioles
Bronchi divide into smaller bronchi until they are tiny bronchioles
These branch smaller. The smallest branches called alveolar ducts which terminate in alveolar sacs
Alveolar sacs look like a bunch of grapes