Respiratory System

Question 1

What are the different pleural structures in the thoracic cavity?

Answer 1

Mediastinal parietal pleura: the serosa on the mediastinum

Pericardial pleura: part of the mediastinal pleura

Costal parietal pleura: the serosa lining the thoracic wall

Diaphragmatic parietal pleura: the serosa lining the diaphragm’s thoracic side

Question 2

Is there positive or negative pressure in the pleural cavity?

Answer 2

negative pressure.

Question 3

What structures run through the mediastinum?

Answer 3

Heart, thymus, esophagus, trachea, vessels, nerves.

Question 4

Which species of animals do NOT have a complete mediastinum and what does that imply?

Answer 4

Dogs, sheep, and horses do not have a complete mediastinum, allowing free communication between the two pleural sacs.

Question 5

What are the right and left nasal cavities are separated by?

Answer 5

Nasal septum.

Question 6

Rostral conchae

Answer 6

Dorsal nasal conchae: extension of the ethmoid bone’s cribriform plate

Ventral nasal concha: a separate and distinct bone of the skull

Question 7

Dorsal meatus

Answer 7

narrow passageway between the dorsal nasal conchae and the nasal bones

Question 8

Middle meatus

Answer 8

passageway between the dorsal nasal concha and the ventral nasal concha

Question 9

Ventral meatus

Answer 9

largest meatus located between the ventral nasal concha and the hard palate.

It leads directly into the nasopharynx.

Question 10

Common meatus

Answer 10

narrow vertical space between the nasal septum and the conchae, from the roof to the floor of the nasal cavity.

Question 11

Caudal conchae

Answer 11

-ethmoid conchae or ethmoturbinates
-narrow clefts = ethmoidal meatuses
-turbinate mucosa is well vascularized and warms the inhaled air
-olfactory epithelium is located in the caudal portion of each nasal cavity
-more complicated in species with an enhanced sense of smell

Question 12

What bones make up the nasal cavity?

Answer 12

Nasal, maxillary, palatine, incisive bones make up the nasal region.

Question 13

What are the boundaries of the nasopharynx?

Answer 13

Nasopharynx - boundaries are the caudal nares and the palatopharyngeal arch

Extends from the caudal nares to the laryngopharynx.

Question 14

What are the boundaries of the oropharynx?

Answer 14

Oropharynx - Demarcated by the palatoglossal arches and the epiglottis.

Question 15

What are the boundaries of the laryngopharynx?

Answer 15

Laryngopharynx - demarcated by the epiglottis and the esophageal entrance.

Question 16

What is the function of the pharynx?

Answer 16

Functions as a passageway for the digestive and respiratory systems. Connects the nasal cavity with the trachea and the oral cavity with the esophagus.

It regulates the passage of air to the lungs and food to the esophagus.

Question 17

What are the 5 openings of the pharynx?

Answer 17

1. pharyngeal opening
2. caudal nares
3. pharyngeal openings of the auditory tubes
4. laryngeal opening
5. esophageal opening

Question 18

What are the five hyoid bones?

Answer 18

Stylohyoid
Epihyoid
Ceratohyoid
Basihyoid
Thyrohyoid

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Question 19

Laryngeal Cartilages: Epiglottic cartilage

Answer 19

-rostral-most cartilage
-gives structure to the epiglottis
-attached to the root of the tongue, basihyoid, thyroid cartilage

Question 20

Laryngeal Cartilages: Thyroid cartilage

Answer 20

-largest cartilage
-two lateral plates which join ventrally, but are open dorsally
-forms the major part of the laryngeal floor
-equivalent to the “adam’s apple” in man

Question 21

Laryngeal Cartilages: Cricoid cartilage

Answer 21

-signet ring shaped cartilage
-connects the thyroid cartilage to the trachea

Question 22

Laryngeal Cartilages: Arytenoid cartilages (paired)

Answer 22

articulates medially with the rostral dorsal border of the cricoid cartilage

Question 23

What are the lateral ventricles of the larynx?

Answer 23

lateral depressions just cranial to the vocal folds.

they allow the vocal cord lateral movement.

Question 24

What are the Vocal cord/fold of the larynx?

Answer 24

-mucosa-covered ligament and muscle caudal to the ventricle

-it extends from the vocal process of the arytenoid cartilage to the interior floor of the thyroid cartilage

Question 25

What cranial nerve, nerve branch, and muscle is responsible for abducting the vocal folds?

Answer 25

Cranial nerve: vagus nerve (CN 10)

Nerve branch: recurrent laryngeal nerve, a branch of the vagus nerve

Muscle: dorsal cricoarytenoid muscle

Question 26

What are the different divisions of the respiratory tree?

Answer 26

Primary bronchi → secondary bronchi inside lungs.
Secondary bronchi → tertiary bronchi.
Tertiary bronchi → bronchioles.
Bronchioles → terminal bronchioles.
Terminal bronchioles → respiratory bronchioles.
Respiratory bronchioles → alveolar ducts.
Alveolar ducts terminate into alveolar sacs.
Alveolar sacs terminate into alveoli.

Question 27

Bronchus

Answer 27

-airway whose walls are reinforced by the presence of cartilage plates
-R/L primary bronchus
-NO gas exchange occurs here

Question 28

Bronchioles

Answer 28

smaller airways whose walls DO NOT contain cartilage or submucosal glands

Question 29

Respiratory bronchioles

Answer 29

<1mm diameter
-walls contain some alveoli
-they conduct air and allow gas exchange
-no cilia, cuboidal epithelium

Question 30

Alveoli

Answer 30

-principal sites of gas diffusion between air and blood
-thin-walled sacs
-single layer of epithelial cells and elastic fibers, surrounded by a fine network of capillaries
-alveolar epithelium and capillary endothelium are closely associated
-secrete surfactant that reduces the surface tension of water and keep the alveoli from sticking together

Question 31

What are the two kinds of alveolar epithelium?

Answer 31

Type 1 pneumocytes
- flat, squamous epithelium
- gas exchange

Type 2 pneumocytes
- cuboidal cells
- secrete surfactant

Question 32

What is the gross anatomy of lung lobes?

Answer 32

Canines:
Two (2) left lobes
Cranial lobe
- cranial part
- caudal part
Caudal lobe
Four (4) right lobes
Cranial
Middle
Caudal
Accessory lobe

Horses:
Cranial/caudal lobes

Question 33

What is pulmonary circulation?

Answer 33

pulmonary arteries from the RIGHT heart feeds the pulmonary capillary networks surrounding the alveoli.

pulmonary veins from after the alveolar capillaries and carry oxygenated blood to the LEFT heart.

Question 34

What is Bronchial circulation?

Answer 34

-arteries come off the aorta
-enter the lung at the hilus
-bronchial arteries run along the branching bronchi and supplies the tissues, except the alveoli
-bronchial veins drain the bronchi, but most blood moves into the pulmonary circulation

Question 35

What is the anatomy of the equine guttural pouches?

Answer 35

Guttural pouches:
-large, ventral diverticula of the auditory tubes
-several cranial nerves and the internal carotid artery pass next to the dorsal part of the pouch
-stylohyoid bone partially separates the pouch into lateral and medial compartments

Parts;
-lateral compartment of guttural pouch
-medial compartment
-stylohyoid bone
-membranous wall
-rectus capitis and longus capitis
-epiglottis

Question 36

What are the anatomic abnormalities encountered in Brachycephalic Airway Syndrome?

Answer 36

-Elongated soft palate
-Stenotic nares
-Everted laryngeal saccules
-Hypoplastic trachea