Chapter 23: Respiratory System
What does the Respiratory system consist of?
-Nose, Pharynx, Larynx, Trachea, Bronchi, and Lungs
What are the parts of the Upper and Lower Respiratory Systems?
-nose, pharynx, and associated structures
-larynx, trachea, bronchi and the lungs
What is the Bony Framework for the external nose?
Made up of the frontal, nasal and maxillae bones.
-The external nose is also made up of the cartilaginous framework
What are the 2 openings on the underside of the nose, and what is their function?
-External Nares, or Nostrils
Function: filtering, warming and moistening incoming air, detecting olfactory stimuli, and in modifying speech
Describe the Large Cavity.
It is in the skull inferior to the nasal bone and superior to the mouth. It connects to the exterior nose anteriorly; it connects tot eh pharynx via two openings, which are the internal nares. Ducts from the Paranasal Sinuses connect to the internal nose.
What are the bones that contain sinuses?
Frontal, Sphenoid, Ethmoid, and Maxillae
What are the bones of the internal nose?
Ethmoid, Maxillae, Lacrimal, Palatine, and the inferior Conchae
What is the space within the internal nose?
The Nasal Cavity
What is the Anterior Portion of the nasal cavity?
What is the Vestibule separated by?
The Nasal Septum
-consisting of cartilage, the ethmoid, maxillae, palatine, and vomer bones
What does the vestibule contain?
It contains the Superior, Middle, and Inferior Meatuses (that are covered with mucous membranes)
-the vestibule is also lined with hairs
What lies on and near the Superior Meatus?
Describe the dimensions of the Pharynx
It is the throat.
-it's about 5 inches long and starts at the internal nares and extends to the larynx
-the walls are skeletal muscle and it is lined with mucous membrane
What is the Pharynx a passageway for?
it is a passageway for Food and Air
What are the 3 regions of the Pharynx?
Describe the Nasopharynx
-extends from behind the nasal cavity to the soft palate.
-there are 5 openings from it: 2 to the nose through the internal nares; 1 to the oropharynx; and 2 to the Eustachian tubes (which may drain into ears when young) to the inner ear
-it also contains the Pharyngeal Tonsil
Describe the Oropharynx
-extends from the soft palate to the level of the hyoid bone
-it has 1 opening, the Fauces, from the mouth
-contains the Palatine and Lingual Tonsils
Describe the Laryngopharynx
-begins at the hyoid bone and extends to the larynx
-ha an opening to the esophagus
Describe where the Larynx lies and what is is made up of.
-AKA the Voice Box
-connects the laryngopharynx with the trachea
-composed of 9 pieces of cartilage (thyroid cartilage is the Adam's apple)
What is the Epiglottis?
A large leaf-shaped cartilage that covers the Glottis (the vocal cords) during swallowing.
-this allows foods to pass through the esophagus and not travel through the opening in the glottis which leads to the trachea
Describe where the Trachea lies.
-is about 5 inches long
-extends from the larynx to the upper portion of the right and left bronchi
What makes up the Trachea?
The walls consist of mucosa, submucosa, hyaline cartilage, and adventitia which is composed of areolar connective tissue
-it is surrounded by C-shaped cartilage rings which keep it open
Describe the left and right Bronchi
-which is more vertical in angle, enters the right lung
-enters the left lung
What dot he bronchi do as the go farther into the lungs?
-they subdivide into secondary and tertiary bronchi and eventually terminate in bronchioles, much smaller tubules of the respiratory tract
-the Terminal Bronchioles subdivide into microscopic branches, Respiratory Bronchioles, which subdivide into alveolar ducts which terminate in cup-shaped air sacs (called Alveoli)
What are Alveoli composed of?
-composed of simple squamous epithelium which allows for diffusion of gases (look like grapes and are at the ends of bronchi branches)
What are the Lungs?
Paired cone-shaped organs located in the thoracic cavity
What is the location of the lungs?
-they extend from the clavicle to the diaphragm. The inferior portion is broad and termed the Base; the superior portion is pointed and is termed the Apex
Compare the Right and Left Lungs
-has a superior, middle and inferior lobes separated by an oblique fissure and horizontal fissures
-has two lobes, and superior and inferior, separated by an oblique fissure
Involves inhalation and exhalation of air between the atmosphere and the lungs
Is the exchange of gases between the alveoli in the lungs and the blood in the pulmonary capillaries
-the blood gains oxygen and the alveoli gain carbon dioxide (from blood)
The exchange of Gases between blood in systemic capillaries and tissue cells
-the cells gain oxygen and the blood acquires carbon dioxide
What are Inhalation and Exhalation governed by?
-when pressure increases, volume decreases and the converse is also true
What needs to happen for Inspiration to occur?
-Diaphragm contracts, which lowers it, and the external intercostals muscles contract, which expands the ribs
-This causes an increase in the size of the thoracic cavity; the pressure decreases and is lower than atmospheric pressure; therefore air flows in passively
-When the diaphragm recoils and the external intercostals relax, the diaphragm decreases in size, the pressure increases, and exhalation occurs passively
What percent of Oxygen dissolves into the blood?
1.5% of oxygen dissolves into the blood; O2 is nonpolar and blood is polar so little dissolves
What happens to the O2 that doesn't dissolve into blood?
98.5% of O2 gets bonded with Hb (hemoglobin) as HbO2 (oxyhemoglobin) inside RBCs
-only dissolved O2 can diffuse out of capillaries and into tissue cells
How much O2 can bind to Iron in Hemoglobin?
4 O2 can bind to 4 Fe (iron) atoms in Hb when fully saturated (at 98% at 105 mm of Hg)
How can more oxygen combing with Hemoglobin?
-The more oxygen present, the more it combines with hemoglobin
-able to diffuse into blood plasma
-combines with amino groups of AA and proteins; high PCO2 creates carbaminohemoglobin in tissue capillaries
-PCO2 goes down in pulmonary capillaries- dissociate to release CO2= where it diffuses into the alveoli in the lungs
Bicarbonate Ions (HCO3)
-transported in blood plasma; carbon dioxide combines with water in the presence of carbonic anhydrase (catilyzed formation of carbonic acid) to form Carbonic, which dissociates into H+ ions and HCO3 ions in to blood
-medullary rhythmicity center
2s- inspiration (duration)
3s- expiration (duration)
connects to Diaphragm (to control it)
Connects to ribs
-Pneumotoxic Area: Pons (above medulla)
-limit duration of inhalation and facilitates expiration
-inhibits expiration and activate and stimulate inspiration
In the Aorta and Carotid bodies (pick up these levels)
-Medulla: CO2, O2
-Hyperventilation: allows exhalation of O2
-Hypoventilation: slow exhalation of CO2
-if there is a rapid exhalation of CO2, then the blood gets overly basic
In Bronchi and Bronchiole (body position)
-stretch receptors: Hering and Breuer
-so that lungs don't bust