Organs of Respiration in the Cat
Examine these slide at low power first to find the field which best demonstrates the listed features. Label the indicated features, and briefly describe their functions.
Locate and examine the following organs of the respiratory tract in the cat. Review the function of each as you locate them.
Here is an image of fresh lungs deflated and then inflated to show the dramatic difference in volume.
(See Gilbert, Pictorial Anatomy of the Cat, pp 37-41)
Make three illustrations:
1) anterior view of entire respiratory system
2) view down into larynx
3) mid-sagittal section of head
1) ANTERIOR VIEW OF WHOLE SYSTEM
Clear away muscles to see: (Here is a labeled anterior view of the larynx.)
thyrohyoid membrane (connects the larynx to the hyoid bone)
thyroid cartilage (largest of the laryngeal cartilages, forms the front of the larynx)
cricoid cartilage (ring shaped cartilage upon which the larynx sits)
esophagus (behind trachea)
R & L pleural cavities (Here is a labeled view of the thoracic respiratory organs.)
anterior lobes of R & L lungs (termed superior lobes in human)
middle lobes of R & L lungs (termed middle in human, L lacking)
posterior lobes of R & L lungs (termed inferior lobes in human)
root of the lungs
bronchi (behind heart, esp on R side)
pulmonary ligament, attached to:
heart lung preparation
In butchering, the heart and lung are removed from the thorax as a unit. These images show the heart nestled between the right and left lungs of a goat.
2) VIEW DOWN INTO LARYNX
Make a transverse cut through the thyrohyoid membrane and esophagus well above the top of the larynx. Do not cut the epiglottis. Lift the larynx up out of the throat. Snip the esophagus to open it up to below the larynx.
false vocal cords
3) MID-SAGITTAL SECTION THROUGH THE HEAD AND NECK: (p. 39 in Gilbert)
Students may make this cut in order to view the following set of features. First, taking care to be exactly mid-sagittal, make a clean cut with a sharp scalpel through successive soft tissues of the tongue (from below) and pharynx to bone (through the neck to the vertebral column), then use a sharp hacksaw to cut through skull and vertebra. Wash the cut surfaces to view the features more clearly. Note that one half will show the nasal septum, the other the conchae.
If you do not make this cut, view a cat which has been so prepared. Each student should locate the following features on this mid-sagittal section:
external nares (external nose openings)
eustachian tube opening (near the sella turcica)
nasopharynx (“pharynx” in cat)
sphenoid sinus (directly above nasopharynx)
palatine tonsils (lateral rear wall of the mouth)
genioglossus muscle (main muscle of tongue)
fenulum (membrane ties tongue down)
Here is a labeled view of a midsagittal section of the head.