The Respiratory System - Avian and Mammalian Lungs - Veterinary Medicine PDF

The Respirato ry System Learning Objectives List the components of the upper respiratory tract and describe their structure and functions. Discuss the main issues of animals with brachycephalic obstructive airway syndrome. List the components of the lower respiratory tract and descr...

The Respirato ry System Learning Objectives List the components of the upper respiratory tract and describe their structure and functions. Discuss the main issues of animals with brachycephalic obstructive airway syndrome. List the components of the lower respiratory tract and describe their structure and functions. Describe the avian respiratory system – structure and function. Describe the events that occur during inspiration and expiration. List the muscles involved in inspiration and expiration. Define the terms tidal volume, minute volume, and residual volume. Describe the processes of oxygen and carbon dioxide exchange between the alveoli and the blood. Normal feline chest radiographs Normal canine chest radiographs Upper Respiratory Tract Lateral radiograph showing canine laryngeal cartilages and trachea Frontal view of turbinates of a deer – scrolls of very thin bone Gutteral Pouch – lined with resp. epith’m - odd-toed mammals, bats - surrounded by parotid and mandibular salivary glands - function? http://www.gemequine.co.uk/services/digital- video-endoscopy Viborg’s Triangle Ramus of mandible rostrally Sternomandibulari s m. Linguofacial vein Importance – surgical access to guttural pouch Scoping the guttural pouch Equine pharynx – entrances to guttural pouches http://www.gemequine.co.uk/services/digital-video- endoscopy Clinical Bacteria/viruses Tumors issues with Foreign bodies upper Parasites respiratory Anatomy tract Bot fly larva removal from anesthetiz ed kitten - watch if you dare! Rhinitis or rhinotracheitis  Chronic rhinitis in a rabbit (L) (Pasteurella multocida), nasal turbinate tumor in a dog (R) Epistaxis Spaniel with nasal tumor on right side Normal turbinates (left) vs. abnormal eaten away turinates in rabbit with https://vet.uga.edu/ivcvm/courses/ cronic nasal infection (right). VPAT5316/01_respiratorypath/09_neoplastic/neopl01.htm  Bovine nasal passages (normal – upper image) Ovine nasal passages with bacterial rhinitis (below) https://veteriankey.com/respiratory-system-mediastinum- and-pleurae/  Brachycephalic dog/cat issues: Elongated soft palate and stenotic nares, hypoplastic trachea, and, and….. Brachycephalic Obstructive Airway Syndrome (BOAS) http://vethq.com.au/what-is-bas/ BVA policy - Brachycephalic dogs Brachycephalic Obstructive Airway Syndro me (BOAS) Everted laryngea saccules https://thehappypuppysite.com/brachycephaly- Stenotic nares surgery on a French bulldog  Larynx Laryngeal folds - p aralysis in a cat first 20 sec Laryngeal paralysis Glottis https://www.petmd.com/blogs/fullyvetted/2012/june/laryn geal_paralysis_common_cause_of_respiratory_difficulties_ in_dogs-26124 Know: arytenoid cartilage/fold, vocal fold (cord), epiglottis, glottis https://adelaidevet.com.au/about/patients/sootis-case-of-laryngeal-paralysis Intubation – lidocaine spray prior for cats to avoid spasm of larynx Intubation of a poi nter (need Dove access for this video) Intubating lab with elongated soft pala te 3:30 – 4:25 https://www.atdove.org/video/canine- endotracheal-intubation  Trachea Yorkie with tracheal collapse Tracheal collapse - endosco py ral chest radiograph canine showing narrowed trachea Bronchial tree (lower respiratory tract) Scope view down horse's trachea and bronchial tree 0 - 2:10 Bronchial tree Bronchitis – lower airway disease Pneumonia – alveolar disease 1 alveolus, 2 alveoli Alveoli in clusters called alveolar sacs  Pneumonia – alveolar disease Pneumonia in a foal – bacteria spread Bacterial pneumonia in a pig through blood stream acquired through the air (breath in Feline asthma – small airway disease Feline asthma cough Cat getting asthma meds using puffer and pediatric chamber Normal lungs Asthmatic cat lungs  Aspiration pneumonia Foreign material breathed in Careful giving oral liquid meds (barium ) Make sure able to swallow before removing endotracheal tube (ETT) Doing surgery without an ETT?  Mammalian lungs Most domestic animals 2 lobes on left, 4 on right Horse – 2 on left, 3 on right Feline lungs Canine lungs – dorsal view – dorsal view Canine lungs Left Right Avian Respiratory System Avian respiratory Main differences: ystem animation Air sacs (5 cranial, 4 Simplified model - shows one-way flo caudal) + lungs w through lungs One-way flow One-way air flow model – note capillaries in parabronchi flow at 90 o angle to flow of air through parabronchi – so efficient! Avian respiratory system differences compared to mammals No soft palate Choana (closes when swallowing) No epiglottis No vocal cords Syrinx Tracheal cartilages complete rings Gr horned owl hard palate No diaphragm chicken Syrinx An enlargement of the trachea where it bifurcates Vibrating walls Each side can vibrate independently creating 2 toned calls Scope view of syrinx Bird song 3:00 – 4:40  Expiration – Recall in mammals aka exhalation Inspiration – Diaphragm relaxes aka inhalation Internal intercostal Diaphragm muscles – contracts – from contraction rotates dome to flat ribs back and down External intercostal Abdominal muscles muscles – (if needed) contraction lifts ribs up and out Control of breathing In pons (part of brainstem) - centre to control rate of breathing In medulla separate centres for insp, exp, and breath holding Efferent messages sent by subconscious to respiratory muscles Can be overridden by conscious mind Mechanical control Stretch receptors in the lungs Normal breathing pattern Preset points Chemical control Homeostasis! Monitors CO2, pH, O2 in arterial blood Chemoreceptors in heart, medulla and carotid arteries and aorta Homeostasis