Respiratory System Chapter 23 A&P 2

Pulmonary ventilation (breathing)

movement of air in and out of the lungs

External respiration

movement of oxygen from the lungs into the blood; movement of carbon dioxide from the blood into the lungs; exchange between alveoli and deoxygenated blood in pulmonary capillaries

• Depends on partial pressure gradients, matching alveolar ventilation & pulmonary perfusion (blood flow), and respiratory membrane structure

Transport of gases

transportation of oxygen to the body tissues and carbon dioxide from the tissues by the blood

Internal respiration

movement of oxygen from the blood into the tissues; movement of carbon dioxide from the tissues into the blood

External nares

The nostrils

Internal nares

two small openings to the throat

Paranasal sinuses

lighten the skull and warm the air that is breathed in provides an airway, warms, moistens, and filters the air breathed in, olfactory receptor cells, and modifies sound for speech

Nasopharynx

superior portion that lies behind the nasal cavity, extends down to the soft palate (for air only)

During swallowing, the ____________ is closed off by the soft palate and uvula, preventing food from entering the nasal cavity (doesn’t work very well when you laugh)

Oropharynx

middle portion extending from the soft palate to the hyoid bone (for food and air)

Laryngopharynx

inferior portion extending from the hyoid down to the larynx and esophagus (for food and air)

Larynx (voice box)

Provides an airway, Channels food and air into the proper tube (i.e. esophagus and trachea respectively), Voice production

Thyroid cartilage (Adam’s apple)

front wall of larynx

Epiglottis cartilage

elastic cartilage, closes off the glottis walls during swallowing

Glottis

mucous membranes & vocal cords

Arytenoids cartilage

involved in vocal cord function

Cricoids cartilage

forms inferior larynx

Corniculate & Cuneiform cartilage

forms lateral & posterior walls

Vestibular folds

false vocal cords - Mucosal folds

Vocal folds

true vocal cords — Ligaments that vibrate

Phonation

sound production

• Occurs by moving air across the vocal cords

• Tighter cords – high sounds

• Relaxed cords – low sounds

Trachea

• Also called the “windpipe”

• Is 5 inches long, 1 inch in diameter

Mucosa

• Inner layer of trachea

• ciliated epithelium

• Filters out things we don’t want in our lungs

Submucosa

• Connective tissue

• Houses glands that secrete mucus

“Tracheal cartilage”

hyaline, C-shaped rings

Carina

where the trachea branches

Tracheotomy

making an incision in the trachea to open the airway

Intrapulmonary Pressure

• pressure inside the alveoli

• Between breaths = atmospheric pressure (760 mmHg)

• During inspiration it is less than atmospheric pressure

• During expiration it is greater than atmospheric press.

Intraplueral pressure

• pressure in the pleural cavity

• Must always be less than intrapulmonary pressure (creates a negative pressure)

  • This keeps the lungs inflated and working

Boyle’s Law

pressure of a gas (air) in a closed container (lungs) is inversely proportional to the volume of the container (with temperature constant)

Airway Resistance

friction encountered by the air as it enters

Alveolar surface tension

Causes difficulty breathing

Compliance

Ease at which the lungs expand

Tidal Volume

(tv) volume of one breath 500mL

Inspiratory reserve volume

(IRV) – maximum amount of air you can forcibly inspire beyond the tidal volume

Expiratory reserve volume

maximum amount of air you can expire after normal tidal volume expiration (1000-1200 mL)

Residual volume

(RV) – amount of air remaining in the lungs after you forcibly exhale (1200 mL) – keeps the alveoli open

Inspiratory capacity

• (IC) = TV + IRV

• Max. you can inhale

Functional residual capacity

• (FRC) = RV + ERV

• Air left in lungs after normal expiration

Vital capacity

• (VC) = TV + IRV + ERV

• Max. you can exhale after you max. inhale

Spirometer

measures lung volumes and capacities

Eupnea

normal quiet breathing (12 breaths per minute in normal, healthy adults)

Dalton’s Law of Partial Pressures

In a mixture of gases (i.e. air), each individual gas has its own partial pressure (i.e. oxygen and carbon dioxide)

Henry’s Law

When a gas is in contact with a liquid, the gas will dissolve in the liquid in proportion to its partial pressure

• The greater the gas concentration, the more and faster it will go into solution in the liquid

Bohr Effect

Refers to the physiological phenomenon where increased levels of carbon dioxide or decreased pH (higher acidity) in the blood lead to a reduction in hemoglobin's affinity for oxygen, facilitating oxygen release to tissues.

Haldane Effect

The physiological phenomenon where deoxygenation of hemoglobin increases its affinity for carbon dioxide, facilitating the removal of carbon dioxide from tissues. (Similar to the Bohr Effect)

Hypoxia

Lack of oxygen