The Respiratory System

Chapter 10

The Respiratory System

•_________ Respiratory Tract (structures outside of the lungs)

• Nostrils• Nasal passages• Pharynx• Larynx• Trachea

•_________ Respiratory Tract (structures within the lungs)• Bronchi• Bronchioles• Alveolar ducts• Alveoli

Intro to the Respiratory System

• The primary function of the respiratory system is to bring ___________ into the body and to carry _________ __________ out of body.

• Respiratory system works together with the cardiovascular system!

• Secondary functions: • Phonation (voice production)• Regulation of body temperature• Regulation of acid-base balance • Sense of smell

Two types of Respiration

• ____________ Respiration

• Occurs in capillaries of pulmonary circ.• Is the exchange of oxygen and carbon

dioxide between the air that is inhaled into the lungs and the blood flowing through the pulmonary capillaries.

• ____________ Respiration

• Occurs in capillaries of systemic circ.• Is the exchange of oxygen and carbon

dioxide between the blood in the systemic capillaries and all of the cells and tissues of the body.

Voice Production

• Also called ____________.• Begins in the larynx (voice box).

• 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.

Body Temperature Regulation• 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 circulating through the lungs and causing hypothermia.

• Hot Conditions:• Aids in cooling through panting.• Rapid respiration movements caused during panting cause increased

evaporation of fluid from the lining of the respiratory passages and mouth, which helps to cool the blood vessels under the epithelium.

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 ______ (acceptable range of 7.35-7.45).

• 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.

Sense of Smell• Also called the _________ sense.

• Many animals have less sensitive eyesight than humans, but a highly sensitive sense of smell.

• Receptors are contained in two patches of sensory epithelium located up high in the nasal passages.

• Olfactory cells are mixed with supporting cells in the patches.

• Hairlike 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.

Upper Respiratory Tract

• Nostrils• Nasal passages• Pharynx (throat)• Larynx (voice box)• Trachea (wind pipe)

The Nose

• ____________: nostrils; external openings of the respiratory tube

• ___________ ______________: between the nostrils and pharynx

• Nasal __________- separates the left nasal passage from the right

• Hard and Soft __________- separate the nasal passages from the mouth.

• Contain _____________ (nasal conchae): thin, scroll-like bones covered with nasal epithelium that occupy most of the lumen of the nasal passages.

• 2 sets (dorsal and ventral) that divide each nasal passage into 3 main passageways

• Each passageway is called a ____________.• Ventral, middle, dorsal and common

Lining of the nasal passages

• Lined with _____________ _____________ epithelium

• _________ project from the cell surfaces up into a layer of mucus

• Mucus is secreted by _________ cells.

• Extensive complex of large blood vessels lies just beneath the nasal epithelium.

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.

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.•

• Can be treated with antibiotics and decongestants, but if ineffective, a hole may need to be drilled into the sinus to allow drainage.

Pharynx (Throat)

• Common passageway for both _____________ and _____________ systems.

• Rostral end is divided into:• _______pharynx (respiratory passageway, dorsal)• _______pharynx (digestive passageway, ventral)• Divided by the soft palate

• Caudal end is divided into:• ___________ (digestive passageway, dorsal)• ___________ (respiratory passageway, ventral)

Larynx

• Commonly called the “voice box”

• • Short, irregular tube that connects

the _________ with the trachea.

• Made of segments of ___________ that are connected to each other and the surrounding tissues by muscles.

• Supported by the hyoid bone.

• Cartilage components: *epiglottis, *arytenoid cartilages, thyroid cartilage, cricoid cartilage

Laryngeal Cartilages

• Epiglottis

• Single, leaf-shaped; projects forward from the ventral portion of the larynx

• During swallowing, the epiglottis is pulled back to cover the opening of the larynx

Laryngeal Cartilages

• Arytenoid cartilages

•Paired; attachment site of the vocal cords•Muscles adjust the tension of the vocal cords by moving the cartilages. •Arytenoid cartilages and the vocal cords form the boundaries of the _________-the opening into the larynx.

Laryngeal Cartilages

• Thyroid cartilages• Shaped as a V that forms and supports the ventral portion of the larynx.

• Cricoid cartilage• Ring-shaped, helps form and support the caudal portion of the larynx.

Breathing and Swallowing

• Because it is a common passageway that must allow both breathing and swallowing, delicate reflexes control the actions of the muscles around the pharynx

• Larynx and pharynx work together to prevent swallowing from interfering with breathing and vice versa.

• Swallowing:• Breathing stops

• Opening to the larynx is covered (by epiglottis)

• Moving of material to be swallowed to rear of pharynx

• Esophagus opens and material moves into it

• Larynx reopens

• Breathing resumes

Laryngeal Functions

• 1. Voice Production

• Originates at vocal cords in the larynx.• Vocal cords are two bands attached to

arytenoid cartilages that stretch across the lumen of the larynx.

• As air passes over vocal cords, they vibrate and produce sounds.

• Muscles attached to arytenoid cartilages control the tension of the vocal cords.

• Lessening tension of the vocal cords allows for __________ pitched sounds.

• Tightening of the vocal cords allows for _________ pitched sounds.

Laryngeal Functions

• 2. Prevention of Foreign material being inhaled.

• During swallowing, muscle contractions pull the larynx forward and fold the epiglottis back over its opening.

• 3. Control of airflow to and from lungs.

• Adjustments in the size of the glottis.• Closure of glottis necessary to cough, strain (lifting,

defecation, urination, parturition)

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.

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. May hear “sighing” patient under anesthesia.

• __________- spasmodic contractions of the diaphragm accompanied by sudden closure of the glottis. Usually self-limiting