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34 Cards in this Set
- Front
- Back
What are the components of the lower airways? |
Trachea-->principle bronchus-->lobar bronchus (secondary)--> segmental bronchus (tertiary)--> small bronchus-->bronchiole-->terminal bronchiole (no further branching)--> respiratory bronchiole (these contain some alveolus-the units of gas exchange)-->alvelolar duct (walls are only alvelous)--> blind ended alveolar sac |
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What is the trachea? |
Flexible, semi-rigid tube Continues into thorax through thoracic inlet where it bifurcates into two principle bronchi at the level of the 4/5th thoracic vertebrae. |
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Trachealis muslce
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forms the roof of the trachea
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Carina
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is the cartilaginous ridge at the tracheal
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What is the sensory innervation of the trachea? |
mechanoreceptors sense foreign material or mucus to initiate coughing reflex. |
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What are the bronchi? |
Similar in structure to trachea, but with cartilaginous plates instead of rings; a little more narrow. One principle bronchus enters each lung. Each principle bronchus branches and te tubing continues to get smaller and smaller |
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What is the bronchopulmonary segment? |
A segmental bronchus and the lung tissue which it ventilate. All of the structures that receive air from a segmental bronchus |
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Pulmonary acinus? |
A respiratory bronchiole and the lung tissue which is ventilates (a respiratory bronchiole and anything that receives air from the bronchiole). Contains many alveoli, arranged in walls of respiratory bronchioles, alveolar ducts, and alveolar sacs. |
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How is ventilation in mammals described? |
It is considered bidirectional. At the end of expiration, stale air remains in the airways and alveoli. On inspiration, fresh air mixes with the stale air, pushing the stale air into the alveoli before any of the fresh air can get in. Once the fresh air does get in, mixes with the stale air. |
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How do the lower airways develop? |
Develop as an outgrowth from embryonic foregut (the point where the pharynx ends, there's a groove that forms, the laryngotracheal groove). |
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What is the respiratory diverticulum? |
Gives rise to epithelium of tracheal mucosa and surrounding mesoderm forms connective tissue and cartilage rings of trachea. |
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What are some of the congenital defects in airway development? |
Tracheo-oesophageal fistulas Tracheal hypoplasia Accessory lungs |
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Tracheo-oesophageal fistulas
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Failure of separation of caudal laryngotracheal groove from foregut, food is able to enter the respiratory tract |
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Tracheal hypoplasia |
abnormal narrowing of the respiratory tract due to defect in growth cartilages |
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Accessory lungs |
Result from extra lung bud, may develop in unusual site |
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What are the components of the lower airways in the bird? |
Trachea |
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Describe the trachea in the bird |
Supported by complete overlapping cartilaginous rings, palpable on RT side of neck. |
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What is the syrinx? |
Vocal organ of the bird. Located at bifurcation of trachea (partly in trachea, partly in bronchi. Tracheal part: strong cartilages |
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Describe the bronchi openings in the bird |
Bronchial openings are separated by vertical wedge-shaped cartilages (pessulus) otherwise no cartilage in walls. Lateral and medial walls contain typanic membranes (produce sound by vibration)
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Describe the bronchi in the bird |
Two principle bronchi: run along ventral aspect of lungs where secondary bronchi arise. Secondary bronchi are connected to each other via tertiary bronchi (Parabronchi). Air capillaries are located in the walls of the parabronchi, this is where gas exchange occurs |
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Secondary bronchi |
Secondary bronchi enter the lungs at regular intervals (they also enter into the air sacs)About 40-50 secondary bronchi (connected to each other in the lung via tertiary bronchi-parabronchi)
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What are parabronchi |
About 400-500 arise from each secondary bronchus. 1-2mm in diameter. Anatomose with each other. Loops between secondary bronchi |
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What are the air capillaries |
Located in the walls of the parabronchi. |
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What are the air sacs? |
Fill up with air upon inspiration and empty the air out on expiration. They push the air through the lungs NOT the site of gas exchange. Expansion of respiratory tract for air intake occurs here because lungs are rigid, act as bellows. |
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Why are fractures serious in birds? |
Can result in subcutaneous emphysema (air comes out of the bones and into the tissues). |
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What are the crainal sacs? |
Cervical |
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Cervical air sacs |
Unpaired; within and adjacent to cervical and thoracic vertebrae |
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Clavicular air sacs |
Unpaired; large fills thoracic inlet and extends into sternum and humeri |
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Cranial thoracic air sacs |
Paired, between sternal ribs, heart and liver |
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Cervicocephalic air sacs |
Only some species (strong fliers) extends over the head and along the neck; communicates with infraorbital sinus, direct communication with nasal cavity |
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What are the caudal air sacs? |
Caudal thoracic |
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What are the caudal thoracic air sacs? |
Paired between the body wall and abdominal viscera |
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What are the abdominal air sacs? |
Paired; caudodorsal abdominal cavity, extending into adjacent vertebral and pelvic bones. |
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Describe the ventilation that occurs in birds |
On inspiration, fresh air flows into the lungs and the caudal air sacs, and stale air moves from lungs into cranial air sacs |