1. Process of Respiration Pressure within the thorax is ____________ with respect to atmospheric pressure. Pulls lungs tight against the thoracic wall Flexible nature of lungs allows them to conform with shape of the thoracic wall. Pleural fluid provides __________. Lungs follow movements of thoracic wall Negative intrathoracic pressure helps draw blood through ________ in the mediastinum and into atria

2. Inspiration = drawing air into lungs (inhalation) Increasing volume of thoracic cavity Main inspiratory muscles: ___________ and ____________ intercostal muscles Expiration = pushing air out of lungs (exhalation) Decreasing volume of thoracic cavity Main expiratory muscles: ___________ intercostal muscles and ____________ muscles

3. Respiratory Volumes ___________ volume – volume of air inspired and expired during one breath. Varies according to body’s needs. Smaller when animal is at rest and larger when excited and active. __________ volume – volume of air inspired and expired during one minute. Calculated by multiplying the tidal volume by breaths per minute. __________ volume – volume of air remaining in the lungs after maximum expiration. Residual volume always remains, lungs will never be completely emptied of air.

4. Alveolar Gas Exchange Simple _________ of gas molecules from areas of _____ concentration to areas of _____ concentration. _____ diffuses from the alveolar air into the blood of the alveolar capillary _____diffuses from the blood into the alveolus

5. BRAND NEW INFO!

6. Voice Production Also called ____________. Begins in the larynx. Two bands called the _______ _______ (or vocal folds) stretch across the lumen of the larynx and vibrate as air passes over them. Thorax, nose, mouth, pharynx, and sinuses may contribute to the vocal sounds.

7. Respiration and Body Temperature Cold conditions: Superficial blood vessels under the epithelium of the nasal passages helps warm inhaled air before it reaches the lungs. Keeps chilled air from causing hypothermia. Hot Conditions: Panting helps to lower body temperature Rapid respiration causes evaporation of fluid from the lining of the respiratory passages, which helps to cool the blood vessels under the epithelium.

8. Acid Base Balance Important homeostatic mechanism in the body. Lower the pH, the more _________ the environment Higher the pH, the more _________ the environment. Normal pH of the blood is ______. CO2 (carbon dioxide) is considered an acid in the bloodstream. The higher the CO2, the lower the blood pH, the more acidic the blood. Respiratory system can alter CO2 content in the blood by adjusting how fast air is breathed in and out.

9. OLFACTION Many animals have a highly sensitive sense of smell. Receptors are in two patches of sensory epithelium located high in the nasal passages. Olfactory cells are mixed with supporting cells in the patches. Sensory processes of the olfactory cells project up into the mucous layer that covers the nasal epithelium When odor molecules dissolve in the mucus and contact the sensory processes, nerve impulses are generated that travel to the brain and are interpreted as smells.

10. Sinuses ________________ of the nasal passages that are contained within spaces in certain skull bones. Each sinus is named after the skull bone that houses it. Most animals have two _________ sinuses and __________ sinuses. Sinuses have same ciliated lining as the nasal passages. Cilia keep fluid and debris from accumulating in sinuses and obstructing the openings of the nasal passages by sweeping it down into the nasal passages.

11. Coughing Cough is generated behind a closed glottis. Breathing muscles contract, compressing the thorax. Builds pressure behind the closed glottis. When glottis suddenly opens, the forceful release of air results in a cough. Purpose of coughing is to clear mucus and other matter from lower respiratory passages. **Closure of glottis also occurs when straining (lifting, defecation, urination, parturition)

12. Other terms __________- similar to a cough, but originates in the nasal passages, burst of air is directed through the nose and mouth in effort to eliminate the irritant. __________- slow, deep breath taken through a wide-open mouth. May be stimulated by slight decrease in oxygen levels, drowsiness, fatigue, and boredom. __________- slightly deeper than normal breath. May serve to expand lungs more than normal. __________- spasmodic contractions of the diaphragm accompanied by sudden closure of the glottis.

13. Endotracheal Intubation Process in which an endotracheal tube is placed through the glottis to the trachea. May be helped by the use of a laryngo________- an instrument that helps to hold down epiglottis. Done blindly in large animals Laryngo_________ –reflex commonly seen in cats, when glottis is touched, larynx slams shut.

14. Respiratory Center Even though all of the inspiratory and expiratory muscles are skeletal muscles under voluntary control, breathing does not require a conscious effort. Breathing is controlled by an area in the _________ ___________ of the brain stem known as the Respiratory Center. Directs timing and strength of contraction Can be consciously controlled for brief periods.

15. Mechanical Control System __________ receptors in the lungs set limits on routine resting inspiration and expiration. Respiratory center sends out nerve impulses when lungs inflate to a certain point Stops muscle contractions that produce inspiration and starts contractions to produce expiration Another set of nerve impulses sent when lungs deflate sufficiently Stops expiration and starts the process of inspiration again

16. Chemical Control System Adjusts normal rhythmic breathing pattern produced by mechanical control system Chemical (peripheral) receptors in carotid artery and aorta monitor blood _____, ____, and ____. Central chemical receptors are located in the medulla oblongata.

17. Chemical Control System Blood level of CO 2 and blood pH linked __CO 2 in blood and __blood pH triggers respiratory center to increase rate and depth of respiration __CO 2 in blood and __blood pH triggers respiratory center to decrease rate and depth of respiration

18. Chemical Control System _______ - decrease in blood O 2 level Slight hypoxia triggers respiratory center to increase the rate and depth of breathing Severe hypoxia - neurons of the respiratory center can become so depressed that adequate nerve impulses cannot be sent to the respiratory muscles Can cause breathing to decrease or stop completely

19. Sinusitis Inflammation of the sinuses. Due to infection, allergies, tumors, etc. Openings into nasal passages swell shut or become clogged with inflammatory debris Fluid in sinuses cannot be passed → ↑pressure → pain Build up of pressure can be very uncomfortable for the animal. TX: antibiotics and decongestants, If ineffective, a hole may need to be drilled into the sinus to allow drainage.

20. Laryngeal Hemiplegia (Roaring) Usually a congenital degeneration of the nerve that supplies the muscles attached to the arytenoid cartilage. At rest usually does not cause a problem When animal exercises, may result in obstruction of the _________ as it “flaps in the wind” when the animal breathes, causing a roaring sound and _____________ intolerance.

21. Aspiration Pneumonia Inflammation of lung tissue due to inhalation of foreign material OFTEN FATAL Causes (easier to prevent than to treat): _______ _________given too quickly ______________ animal inhaling regurgitated liquids. Protection: Head lower than stomach Endotracheal tube cuff NPO 12 h before Sx

22. Collapsing Trachea Mainly seen in ________ dogs Cause unknown, but the smooth muscle portion of some of the tracheal rings is wider/larger than normal. When the animal inhales, the muscle pushes down on the cartilagenous area, obstructing airway. Causes dry, honking _________ and dyspnea if severe. Signs seen during exercise or excitement

23. Asthma Bronchioles are sometimes overly sensitive to certain irritants in the inhaled air.Bronchioles are sometimes overly sensitive to certain irritants in the inhaled air. Results in bronchoconstriction, swelling, and excess mucus productionResults in bronchoconstriction, swelling, and excess mucus production Can range from mild and annoying to life-threateningCan range from mild and annoying to life-threatening More common in humansMore common in humans Often occurs in ______ in the ___________Often occurs in ______ in the ___________

24. Pneumothorax Leakage of air into thorax → Loss of negative pressure in lungs (causes “collapsed lung”) Causes: Penetrating wound of chest Rupture of alveoli Rx Remedy cause Remove air from thorax Needle/syringe (aka ____________________) Chest tube