Respiratory system Flashcards
Functions of the respiratory system:
Primary: Gas exchange
Secondary: - phonation?
- breathing (especially panting) aids in regulation of body temperature?
- breathing plays a role in maintenance of normal acid-base balance in the blood stream?
- breathing has an effect on body hydration?
Gas exchange
– O2 in the tiny air sac spaces (alveoli) of the lungs diffuses into the capillary blood spaces; and, CO2 in the capillary blood space diffuses into the air sac spaces – the exchange of
O2 from the lungs for CO2 from the blood stream is called gas exchange
Inhalation (also known as inspiration) is for the purpose of getting oxygen into the air sacs (to then go to the capillaries) and exhalation (also known as expiration) is for the purpose of getting CO2 out of the air sacs (to then go to the outside of the body)
What is phonation?
the production or utterance of speech sounds.
What effect does panting in dogs and cats have on body temperature?
It helps cool them down
What effect does breathing have on body hydration?
When you exercise you tend to breathe through your mouth, causing dry air to enter your lungs
How does breathing help maintain a normal acid / base balance in the bloodstream?
One mechanism the body uses to control blood pH involves the release of carbon dioxide from the lungs. Carbon dioxide, which is mildly acidic, is a waste product of the processing (metabolism) of oxygen (which all cells need) and, as such, is constantly produced by cells. As with all waste products, carbon dioxide gets excreted into the blood. The blood carries carbon dioxide to the lungs, where it is exhaled. As carbon dioxide accumulates in the blood, the pH of the blood decreases (acidity increases).
Nostrils
openings of the nostrils are called the external nares
Nasal Cavity:
- Separated from the mouth by the hard and soft palate
2. Divided into two halves by the nasal septum (cartilage) and the vomer (bone)
3. Lined by a mucous membrane—a vascular mucous membrane lines the nasal cavity and also covers the nasal turbinates.
Nasal turbinates (conchae):
- Nasal turbinates (conchae): scroll shaped bony structures that are covered by a mucous membrane
– the turbinates serve two functions:
i. they serve to warm the cold inspired air before it goes to the lungs
ii. they serve to trap dust particles, thereby removing dust from the inspired air before it goes to the lungs
-- there are three turbinates on each side (each half of the nasal cavity contains three) for a total of six turbinates
a. two dorsal nasal turbinates
b. two ventral nasal turbinates
c. two ethmoid turbinates
The meatuses
the spaces inside the nasal cavity are called meatuses – the turbinate bones divide
the nasal cavity into four spaces on each side.
- - the four spaces are: a. Dorsal nasal meatus- this is the space that is located above the dorsal nasal turbinates b. Middle nasal meatus- this is the space located between the dorsal and ventral nasal turbinates c. Ventral nasal meatus- this is the space located below the ventral nasal turbinates—this is the largest of the meatuses / this is the only space in the nasal cavity that is large enough to use for passage of a nasogastric tube d. Common nasal meatus- the medially located space next to the septum (the space between the turbinates and the nasal septum
When passing a stomach tube along the floor of the nasal cavity through the ventral nasal meatus the tube is passing just underneath the ventral nasal turbinate. If the end of the tube hits the
ventral nasal turbinate a nosebleed will occur. Where exactly is the blood coming from?
epistaxis
A nosebleed
Sinuses
air filled spaces (cavities) located in certain bones of the skull – sinuses are named according to the bone in which it is located.
Farm animals – the five major sinuses found in farm animals are:
a. Maxillary
b. Frontal
c. Sphenoidal
d. Palatine
e. Lacrimal
Dehorning cattle-
the core (center) of the cornual processes of the horns are hollow / because the horns are hollow on the inside, the frontal sinus will be opened up to the outside when the horns are removed by dehorning surgery
-- dehorning of cattle can lead to infection of the frontal sinus
Dogs/cats prominent sinus
the frontal sinus is the most prominent sinus in dogs and cats.
Pharynx:
The pharynx (throat) serves as a common passageway for food/water (when swallowing) and air during breathing
- The nasal cavity, the middle ear cavities, the oral cavity, the larynx (voice box), and the esophagus have a connection to the pharynx / these connections are:
a. the nasal cavity / internal (posterior) nares (look at a skull to see these)
b. the middle ear cavities / eustachian tubes
c. oral cavity
d. the larynx and thrachea (windpipe) / glottis of the larynx
e. the digestive system / the upper esophageal sphincter
Guttural pouch
an out-pouching of the eustachian tube in the horse; a guttural pouch is located lateral to the pharynx on each side of the neck in the throat area
Three diseases of the guttural pouch:
empyema, guttural pouch mycosis, and guttural pouch tympany
Empyema (what is it?)
an accumulation of pus that may develop secondary to URT infections in horses, esp. those caused by streptococci.
Empyema (clinical signs)
intermittent nasal discharge, painful swelling in the parotid area, +/- stiff head
carriage, and stertorous breathing. Fever, depression, and anorexia may or may not develop.
Empyema (treatment and diagnosis)
Diagnosis: Endoscopy and radiographs.
Endoscopy – the use of an endoscope to view inside hollow tubular structures, etc…
Radiograph – the image produced by using an x-ray machine
Treatment: Penicillin combined with daily lavage of the guttural pouches using a chlorhexidine
flush solution. Refractory cases require surgical drainage.
Guttural pouch mycosis (what is it?)
- a localized or diffuse fungal invasion of the roof of the guttural pouch
clinical sign is epistaxis
Guttural pouch tympany
the affected pouch becomes distended with air and forms a characteristic
non-painful elastic swelling in the parotid region.
Most affected foals appear normal; the cause is unknown; diagnosis is based on clinical signs and age of the animal. Treatment of choice is fenestration of the membrane that separates the affected guttural pouch from the normal (non-affected) guttural pouch.
functions of larynx
a. essential for voice production – the vocal cords are located within the larynx
b. prevents inhalation of food/water and foreign objects into the trachea
cartilage of larynx
a. epiglottis – located at the base of the glottis – can be seen as a pointed
leaf shaped structure when looking into the throat area – it serves to cover the glottis during the act
of swallowing which prevents swallowed food/water from entering the larynx and trachea
b. two arytenoid cartilages – located one on each side of the opening (glottis) of the larynx – these also serve to cover the glottis during the act of swallowing so that food/water can not get into the larynx and trachea.
– when these two cartilages are in the abducted position, the glottis is open / when they are in the adducted position, the glottis is closed
c. thyroid cartilage - the main body of the larynx
d. cricoid cartilage- the cricoid cartilage is located caudal to the thyroid cartilage and is attached to the first cartilaginous ring of the trachea.
Left recurrent laryngeal nerve hemiplegia
-commonly known as roaring
- caused by damage to the left recurrent laryngeal nerve
resulting in a permanent paresis or paralysis of the left arytenoid cartilage and vocal fold.
Clinical signs of roaring in horses:
- Exercise intolerance
2. Abnormal breathing noise occurs during exercise; ie., whistling and a roaring noise is heard during inspiration
3. Affected horses are usually asymptomatic at rest (breathing sounds are usually normal during rest)Diagnosis: Endoscopic observation of abnormal motion of the arytenoid cartilage and vocal cord. Treatment: Prosthetic laryngoplasty is commonly used in racing horses.
The Respiratory Tree
the respiratory tree begins with the trachea and ends at the respiratory
bronchioles and alveoli
