Respiratory

• Respiratory system


  • Conducts inspired air containing oxygen from the atmosphere to the respiratory passages until it reaches the places where the gaseous exchange takes place and expiring the carbon dioxide out of the body
  • Phonation/making of sounds
  • Smell
  • Heat regulation
  • Acid/base balance
• Parts of the Respiratory System

  • Conducting portion (CP)
  • Respiratory Portion
  • Pumping mechanism
• Conducting portion (CP)


  Nose, nasal cavity, larynx, and trachea
• Nose


  • The inspired air enters the nose
  • External nose and nasal cartilages; internal nose or nasal cavity
  • Fascial and rostral portions: muzzle
• Muzzle


  • D - muzzle more than half of the skull
  • B - shortened muzzle
• Nasal plane


  • A flattened epical portion of the nose
• Nostrils/cranial nares


  • Inlet and outlet of the air
• Septum (inside)


  • Divides the nasal cavity into left and right
• Philtrum (outside)


  • Line that separates the nasal portion
• Alar fold


  • Extension of the wing of nostrils; bulbus enlargement
• Wing of the nostrils

  • Thickened dorsal lateral portion
• Nasal cartilage


  • Nasal support
• Bony support of the nasal wall

  • Nasal bone
  • Maxillary bone
  • Incisive bone
  • Frontal bone
  • Lacrimal bone
  • Zygomatic bone
  • Palatine bone
• Nasal cavity


  • Divided into respiratory (below) and olfactory (above for smell)
  • Divided into two by the nasal septum and is occupied by nasal conchae
  • Communicates externally at the nostrils and it communicates posteriorly with the naso-pharynx through the posterior nares
• Nasal conchae


  • Cartilaginous covered with nasal mucosa that occupy the two nasal cavities (left and right)
  • Dorsal nasal conchae - Dorsal part of the nasal cavity which extends from the cribriform of ethmoid bone to the rostral nasal cavity
  • Ventral nasal conchae - Folded filling the middle lumen of the nasal cavity
  • Ethmoidal conchae - Caudal part of the cavity
• Nasal meatuses


  • Passageway between the conchae
  • Dorsal nasal meatus - Dorsal narrow passageway between the dorsal nasal conchae and the nasal bone
  • Middle nasal conchae - Between the dorsal and ventral
  • Common nasal conchae - Narrow vertical space between the nasal septum and the conchae in general
  • Ventral nasal conchae - Largest; between the ventral nasal conchae and the hard palate
• Functions of nasal cavity

  • Olfaction (smell) - Macrosmatic, Microsmatric, Anosmatic
  • Filtration of inspired air - Dust and dirt are trapped in the mucus layer and is removed by the ciliary action
  • Warming and Humidifying Inspired air
• Paranasal Sinuses


  • Frontal and Maxillary Sinuses
  • Impart resonance to the voice
  • Thermally insulate the nervous centers
  • Lighten the area of the olfactory meatus
  • Protect the eyes, nasal passages, and cranial cavity
• Pharynx


  • Nasopharynx - conducts inspired air from the nasal cavity to the larynx
• Larynx


  • Prevent solid materials from going into the trachea, voice, and sound creation
• Laryngeal cartilages


  • Epilottis - Rostral most; closes the laryngeal opening during taking up of food
  • Thyroid - Largest; adam's apple in men
  • Arytenoid - Vocal process (ventral) - attachment of the vocal cord, Muscular process (caudal) - attach. Of intrinsic laryngeal muscle, Corniculate process (dorsal) - horn-like; dorsal opening of the laryngeal
  • Cricoid - Most caudal; connects the the processes into the traches
• Muscles of the Larynx

  • Extrinsic muscles: Sterno-thyro-hyoid, Thyro-hyoid, Hyo-epiglottic
  • Intrinsic muscles: Crico-thyroid, Dorsal crico-artenoid, Lateral crico-arytenoid, Transverse arytenoid, Ventricular, Vocal
• Trachea


  • Cartilaginous and membranous tube
  • Extends from the larynx to the hilus of the lungs
  • Cervical part runs from larynx to thoracic inlet
  • Thoracic part continues at the bifurcation (right and left bronchi)
  • Composed of cartilaginous C-shaped tracheal rings
• Respiratory Portion


  • Lungs - Paired structures, occupies greatly the thoracic cavity; where the interchange of oxygen and carbon dioxide takes place
• Lungs


  • Costal surface - in contact with the thoracic wall
  • Medial surface - faces the opposite lung through the mediastinum
  • Cardiac impression - heart on the lungs
  • Diaphragmatic - to the diaphragm
  • Hilus of the lung - primary and secondary bronchos and nerves enter the lung
  • Cardiac notch - opening between lobes where the heart is in contact
• Pleurae


  • Serous membranes in the surface of the lungs which release small amount of serum-like serous fluid or exudate
  • Reduces the friction with the other organs during respiration
  • Pleura - in contact with the thoracic wall, Pericardial - in contact with the heart, Peritoneal - in contact with the abdomen
• Muscles for Inspiration


  • Scalenus
  • Serratus ventralis
  • Pectoralis
  • Intercostal muscles
  • Latissimus dorsi
  • Diaphragm
• Muscles for Expiration


  • Relaxes and the thoracic cavity decreases in size and elastic tissue contracts, thus expelling the air
• Diaphragm


  • Costal - In contact with the cartilages of the 8th,9th and 10th rib
  • Sternal - Upper part of the cyphoid
  • Lumbar - Right crus - 1st to 5th lumbar vertebrae by the ventral longitudinal ligaments, Left crus - 1st to 2nd lumbar vertebrae
• Diaphragm: pierced foramina


  • Caval foramen - Transmits the vena cava
  • Esophageal hiatus - Esophagial branch of the artery and the vagus nerve
  • Aortic hiatus - Transmits the aorta, vena acigos and the sternal calli
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