CVRS - Respiratory Flashcards
What are the functions of the lungs?
Respiratory - exchange of gases
Non-respiratory
-Pulmonary endothelium secretes ACE
-Acid base balance
- Immune regulation
-Thermoregulation
-Metabolism of phasoactive metabolites
What are the pulmonary volumes?
Tidal volume - amount of air moved in each breath
Inspiratory reserve volume - amount of air that can be inhaled with max effort after normal breath has been inhaled
Inspiration capacity is both these combined
Expiratory reserve volume - amount of air exhaled with max effort after normal breath has been exhaled
Vital capacity is the inspiration capacity plus expiratory reserve volume.
Residual volume is amount of air left in lungs after forceful exhalation.
(functional residual capacity is the normal amount left with normal breath)
Total lung capacity is all of this added
Species variation of the left lung
All domestic animals have 2 lobed left lungs:
Cranial - this itself is also divided cranially and caudally
Caudal
The horse looks like one lobe but is two
Species variation in the right lung
4 lobes
Cranial
Caudal
Middle
Accessory (sits under heart in ventral midline between caudal lobes in own pleura)
Horses hard to see
Ruminants look like 5 lobes but two cranial lobes have same lobar bronchus
Pigs and ruminants the cranial lobe is supplied by tracheal bronchus
What does the diaphragm do and what is it made of?
Made of skeletal tissue and tendons
It contracts, pulling ribcase and changes pressure in thorx.
Supplied by phrenic nerve
What are the pleural membranes?
Visceral pleura
Parietal pleura
Mediastinal
Plica venae cavae
What are pleural membranes made of?
Simple squamous epithelium surrounded by connective tissues derived from somatic mesoderm.
What are the three layers of parietal pleura?
Lines pleural cavity and is thicker. Split into three
Costal pleura - lines ribcage
Mediastinal pleura - lines mediastinal,
Diaphragmatic pleura - lines cranial surface of diaphragm
What is the visceral pleura?
outer surface of lung continuous with parietal with lots of elastic fibres
What is the mediastinal space?
The space in the cavity between the lungs is formed by apposition of the mediastinal pleura of right and left sacs.
Contains most of thoracic cavity (heart, thrachea/oesophagus, mediastinal, great vessesl and nerves)
A fold of the parietal pleura is the pilca venae cavae and contains lungs, caudal vena cava and right phrenic nerve.
What does the upper respiratory tract consist of?
Pharynx and larynx
Describe the pharynx
Common cavity where air and ingested material pass. It connects the oral cavity with the oesophagus and the nasal cavity with the larynx
Where is the pharynx located?
Dorsally - bordered by base of skull and two cranial vertebrae
Ventrally - larynx and mandible
Laterally - pterygoid muscles and suspensory part of hyoid apparatus
Soft palate separates rostral part of pharynx to dorsal and ventral part of naso-/oro-pharynx
What is the larynx?
Its a bilaterally symmetrical tube-shaped musculocartilagenous organ connecting pharynx to trachea
What does the larynx do?
It protects the trachea from foreign material entering when swallowing
Important in vocalisation and increasing intra-abdominal pressure