Anatomy of the Respiratory System Lab Exercise 24 Anatomy of the Respiratory System Portland Community College BI 233

Upper & Lower Respiratory System Upper Respiratory System Nose Nasal cavity Paranasal sinuses Pharynx

Respiratory system Lower Respiratory System Larynx Trachea Bronchi Lungs

Nasal bones Frontal and nasal bones for the nasal bridge and processes of the maxillae make up the lateral walls. Nasal septum divides the nasal cavity into right and left halves formed by vomer and perpendicular plate of the ethmoid

Uvula During swallowing, the soft palate elevates and the uvula closes off the internal nares, preventing food or fluids from entering the nasal cavity.

Nasal Cavity

Nasal Cavity Superior Middle & Inferior Turbinates Opening of Auditory Tube External Nares

Nasal Cavity The nasal epithelium covering the conchae serves to cleanse, warm and humidify the air Nasal conchae increase the surface areas for the mucus epithelium The olfactory epithelium in the upper medial part of the nasal cavity is involved in the sense of smell. The nasal cavity serves as a resonating chamber as well as an avenue for escaping air.

Nasal Turbinates or Conchae Ciliated pseudostratified columnar epithelium with goblet cells pushes trapped dust toward the back of the throat to be swallowed. .

Sinuses All the sinuses are continuous with the nasal cavity are lined by mucous membrane. Mucous secretions drain into the nasal cavities.

Pharynx Connects the nasal and oral cavities to the larynx and esophagus Anatomically divided into 3 sections: Nasopharynx Oropharynx Laryngopharynx

(pseudostratified epithelium) (stratified squamous epithelium) (stratified squamous epithelium)

Tonsils Pharyngeal Tonsils (Adenoids) Palatine Tonsils Lingual Tonsils

Tonsils Pharyngeal tonsils Tonsils: lymphoid tissue. Palatine tonsils

Larynx: aka Voice Box Made of 9 pieces of cartilage, the most important are: Thyroid cartilage (Adam’s Apple) Thyrohyoid membrane Cricoid Cartilage Cricothroid ligament Epiglottis

Larynx Hyoid Bone Thyrohyoid Membrane Epiglottis Thyroid Cartilage Cricothyroid Ligament Cricoid Cartilage Tracheal Cartilage

Inside the Larynx Vestibular Folds: Vocal Cords, or vocal folds Also called false vocal cords, ventricular band of larynx, ventricular folds, and upper folds Vocal Cords, or vocal folds Lower, “true” vocal cords Attach to the arytenoid cartilages by the vocal ligaments (internal) Glottis: The vocal cords and the space (rima glottidis) between them.

Inside the Larynx

Inside the Larynx Corniculate cartilage Cuneiform cartilage Rima Glottis True Vocal Cords Glottis Epiglottis Tongue

Glottis: True cords plus opening Rima Glottis: The opening

Airways Larynx Trachea Right Mainstem Bronchi Left Mainstem Bronchi The carina is the last cartilage which separates the entrances to the left and right primary bronchi Secondary Bronchi Carina Secondary Bronchi

Bronchi The carina of the last tracheal cartilage marks the end of the trachea and the beginning of the right and left bronchi Left main stem bronchus Right main stem bronchus Bronchi subdivide into secondary bronchi, each supplying a lobe of the lungs

Respiratory Tree

Branching of Bronchial Tree Trachea Primary Bronchi Secondary Bronchi Tertiary Bronchi Bronchioles Terminal/Respiratory Bronchioles

Lungs Apex: the part under the clavicle Base: the part touching the diaphragm Costal Surface: the part touching the ribs Hilus: indentation containing pulmonary and systemic blood vessels Left Lung has 2 lobes and a cardiac notch Left upper lobe Left lower lobe Right Lung has 3 lobes Right upper lobe, middle lobe, lower lobe

Lungs Apex Base LUL RUL Oblique fissure Horizontal fissure Hilus Horizontal fissure Cardiac notch Oblique fissure LLL RML RLL Base

Lungs: Medial View

Lung Lobes

Pleura Pleura is the double-layered sac of serous membrane Parietal Pleura is the outer layer and is attached to the thoracic walls Visceral Pleura is the inner layer covering the lung tissue The layers are only touching, they are not fused together The potential space is called the pleural cavity There is serous fluid between the layers which allows them to slide against each other during breathing

Pleural cavity is in between the two layers

Mediastinum The area between the lungs. Posterior to the sternum Anterior to the vertebrae Contains the heart, great vessels, esophagus and thymus

Trachea Histology Composed of three layers Mucosa: made up of goblet cells and ciliated pseudostratified columnar epithelium Submucosa: connective tissue deep to the mucosa Adventitia: outermost layer, has C-shaped rings of hyaline cartilage

Trachea

Trachea Histology

Trachea Histology

Seromucous Glands (Trachea)

Trachea Pseudostratified Columnar Epithelium Submucosa with seromucous glands Hyaline Cartilage

Bronchi Bronchioles Tissue walls of bronchi mimic that of the trachea As conducting tubes become smaller, structural changes occur and eventually they become bronchioles Cartilage support structures change Bronchioles differ from bronchi in that they lack cartilage Epithelium types change Amount of smooth muscle increases

Bronchi Histology

Bronchioles Respiratory Bronchioles Respiratory Bronchioles : Continued branching leads to the area where gas exchange occurs by simple diffusion

Bronchiole Histology Notice the lack of cartilage Simple columnar epithelium Notice the lack of cartilage

Respiratory Bronchioles Alveolar Ducts Alveolar sacs

Alveolar sacs Alveoli Alveolar sacs look like clusters of grapes The “individual grapes” are Alveoli

Alveoli Histology

Type II Pneumocytes are cuboidal and produce surfactant Type 1 Pneumocytes are flattened for gas exchange

Respiratory Membrane The area where gas exchange between air and blood occurs It is the fused alveolar and capillary walls (3 layers) Squamous type 1 alveolar epithelium Fused basal laminae Squamous endothelial cells in pulmonary capillaries

Respiratory Membrane

Respiratory System Physiology Lab Exercise 25 Respiratory System Physiology

Terminology Pulmonary Ventilation: aka breathing, is the movement of air into and out of the lungs External Respiration: The gas exchange between the blood and alveoli (Partial pressure of oxygen in the alveoli is greater than in the blood) Transport of gases: which is how oxygen and carbon dioxide are carried by the blood between the lungs and all tissues Internal Respiration: Exchange of gases between systemic blood and tissue cells (pressures are opposite from external respiration)

Dalton’s law The total pressure of a gas mixture is equal to the partial pressures of all the individual gases in the compound During respiration, oxygen and carbon dioxide will move along a pressure gradient from high conc. To low conc.

Gas Exchange Almost all oxygen (98%) is transported by binding to hemoglobin in RBCs. The remainder simply dissolves in the blood plasma. Most carbon dioxide (68% to 78%) diffuses into RBCs where it is converted to carbonic acid (H2CO3) Carbonic acid quickly dissociates into bicarbonate ions and hydrogen ions

Acid Base Balance in Blood In the RBC and minimally in the plasma, this reaction takes place CO2 + H2O  H2CO3  HCO3- + H+ The bicarbonate ions (HCO3- ) help buffer the blood by combining with extra H+ in the blood. Carbonic acid (H2CO3) releases H+ when the blood becomes too basic. This way, the balance of H+ remains steady and the pH is doesn’t fluctuate.

Carbonic Acid Buffer System: Dealing with Acids CO2 + H2O  H2CO3  HCO3- + H+ (Add an acid) + H+ The H+ will combine with HCO3- to create H2CO3 H2CO3 will then dissociate into CO2 + H2O Breathing will increase to rid the body of the extra CO2

Carbonic Acid Buffer System: Dealing with Bases CO2 + H2O  H2CO3  HCO3- + H+ (Add a base) + OH- The OH- will combine with H+ to create H2O H2CO3 will dissociate into HCO3- + H+ to restore the H+ concentration

Boyle’s Law The pressure of a gas is inversely proportional to its volume. If the volume of the thoracic cavity increases, the air pressure in the airways decreases This results in a pressure gradient that forms between the atmosphere (high) and the air ways (low) forces air to move into the lungs

Pulmonary Ventilation During inspiration, the ribs are elevated and the sternum moves outward. During expiration, the ribs are depressed and the sternum moves inward. The diaphragm is the primary inspiratory muscle

Inspiration/Expiration Inspiration: Increase in thoracic cavity size Inspiratory muscles External intercostals (lift the rib cage) Diaphragm (Becomes flat) Expiration :Decrease in thoracic cavity size Expiratory muscles For the most part it is just the relaxation of the inspiratory muscles (passive process) Internal intercostals & abdominal muscles used only for forced expiration

Muscles of Respiration

Muscles: Inspiration

Muscles: Expiration

Spirometry Diagnostic technique used to measure respiratory volumes The instrument used is a spirometer. It cannot measure the amount of air in the lung, only the amount entering or leaving.

Respiratory Volumes Tidal Volume TV Volume of air moved in or out of the lungs during quiet breathing about 500 mL. Inspiratory Reserve Volume IRV Volume that can be inhaled during forced breathing in addition to tidal volume 3100mL. Expiratory Reserve Volume ERV Volume that can be exhaled during forced breathing after a normal tidal volume 1200 mL.

Respiratory Volumes Residual Volume RV * Can not be measured using spirometry* Volume that remains in the lungs at all times 1200 mL. The sum of two or more of these volumes is known as a pulmonary capacity. The five pulmonary capacities are as follows:

Respiratory Capacity Vital Capacity VC Maximum volume that can be exhaled after taking the deepest breath possible VC = TV + IRV + ERV Inspiratory Capacity IC Maximum volume that can be inhaled after a normal exhalation IC = TV + IRV

Respiratory Capacity Functional Residual Capacity FRC The amount of air left in the lungs after a normal exhalation FRC = ERV + RV Total Lung Capacity TLC * can not be measured using spirometry* Total volume of air that the lungs can hold. TLC = VC + RV

Depth and Rate of Ventilation Eupnea- normal respiratory rhythm Hypoventilation- caused by breathing either too shallowly or too slowly CO2 levels increase and pH lowers. Hyperventilation- a person over ventilates eliminates carbon dioxide faster than it is being produced causing the pH to increase.

Activity 25.2 Expiratory capacity is equal to the sum of the tidal volume (TV) and expiratory reserve volume (ERV) Is the maximum volume of air that can be forcefully exhaled after a normal inhalation. Practice taking expiratory EC, ERV, TV and VC Do Activity 25.3: calculate volumes and capacities follow instructions in manual

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