CHAP 23 ANAPHYSIO TORTORA

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"Respiration"

process of supplying the body with O2 and removing CO2. It has three basic steps: -Pulmonary ventilation -External (pulmonary) respiration -Internal (tissue) respiration."

"Pulmonary Ventilation"

-inhalation (inflow) and exhalation (outflow) of air

• involves exchange of air between the atmosphere and the alveoli of the lungs.

"External Respiration"

exchange of gases between the alveoli of the lungs and the blood in pulmonary capillaries across the respiratory membrane.

"Internal Respiration"

"exchange of gases between blood in systemic capillaries and tissue cells.

respiratory system

consists of the nose, nasal cavity, pharynx (throat), larynx (voice box), trachea (windpipe), bronchi, and lungs

(1) upper respiratory system (2) lower respiratory system

2 Structural Parts of the Respiratory System

upper respiratory system

includes nose, nasal cavity, pharynx, and associated structures

lower respiratory system

includes larynx, trachea, bronchi, and lungs

(1) conducting zone (2) respiratory zone

2 Functional Parts of the Respiratory System

"Conducting Zone"

series of interconnecting cavities & tubes both outside & within the lungs. includez: the nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles; function: filter, warm, and moisten air and conduct it into the lungs."

"Respiratory Zone"

consists of tubes and tissues within the lungs where gas exchange occurs.

• include the respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli -the main sites of gas exchange between air and blood."

"Otorhinolaryngology"

"branch of medicine that deals with the diagnosis and treatment of diseases of the ears, nose, and throat (ENT)."

1. Provides for gas exchange: intake of O2 for delivery to body cells and removal of CO2 produced by body cells.

2. Helps regulate blood pH.

3. Contains receptors for sense of smell, filters inspired air, produces vocal sounds (phonation), and excretes small amounts of water and heat.

"Functions of the Respiratory System"

"Nose"

• entrance of the respiratory system that consists of a visible external portion (external nose)

• an internal portion inside the skull called the nasal cavity (internal nose)."

"External Nose"

-portion of the nose visible on the face ' -consists of a supporting framework of bone and hyaline cartilage covered with muscle and skin and lined by a mucous membrane. -has 2 openings called external nares or nostrils which lead into cavities called nasal vestibules."

"Bony Framework of external nose"

frontal bone, nasal bones, and maxillae form the bony framework of the external nose."

"Cartilaginous Framework of external nose"

consists of several pieces of hyaline cartilage connected to each other and certain skull bones by fibrous connective tissue. components : -septal nasal cartilage - forms the anterior portion of the nasal septum; -lateral nasal cartilages- inferior to the nasal bones; alar cartilages which form a portion of the walls of the nostrils."

The interior structures have 3 functions:

1.warming,moistening & filtering incoming air; 2.detecting olfactory stimuli 3.modifying speech vibrations as they pass through large, hollow resonating chambers.

"Rhinoplasty"

surgical procedure in which the shape of the external nose is altered. -often done for cosmetic reasons but is sometimes performed to repair a fractured nose or a deviated nasal septum.

1. Root: Superior attachment of the nose to the frontal bone.

2. Apex: Tip of nose.

3. Bridge: Bony framework of nose formed by nasal bones.

4. External naris: Nostril; external opening into nasal cavity."

Surface Anatomy of the Nose (4)

"Nasal Cavity"

-large space in the anterior aspect of the skull that lies inferior to the nasal bone and superior to the oral cavity

• lined with muscle and mucous membrane.

• vertical partition, the nasal septum, divides the nasal cavity into right and left sides."

"Nasal Septum"

-anterior portion consists primarily of hyaline cartilage -remainder is formed by the vomer and the perpendicular plate of the ethmoid, maxillae, and palatine bones."

"Internal Nares or Choanae"

-posterior openings of the nasal cavity that communicate with the pharynx."

"Paranasal Sinuses"

-Cavities in certain cranial and facial bones lined with mucous membrane that are continuous with the lining of the nasal cavity. -produce mucus and serve as resonating chambers for sound."

"Nasal Conchae"

3 shelves formed by projections of the superior, middle, and inferior nasal conchae extend out of each lateral wall of the nasal cavity."

"Nasal Meatuses"

conchae subdivide each side of the nasal cavity into a series of groovelike air passages —the superior, middle, and inferior nasal meatuses."

"Tonsillectomy"

Surgical removal of the tonsils.

• usually performed under general anesthesia on an outpatient basis.

• is divided into a larger, inferior respiratory region and a smaller, superior olfactory region."

"Regions of Nasal Cavity"

"Respiratory Epithelium"

respiratory region is lined with ciliated pseudostratified columnar epithelium with numerous goblet cells

"Nasal Vestibule"

anterior portion of the nasal cavity just inside the nostrils, which is surrounded by cartilage."

"Olfactory Epithelium"

olfactory receptor cells, supporting cells, and basal cells lie in the respiratory region, which is near the superior nasal conchae and adjacent septum. These cells make up this. It contains cilia but no goblet cells."

Pharynx(or throat)

-funnel-shaped tube about 13 cm long that starts at the internal nares and extends to the level of the cricoid cartilage, the most inferior cartilage of the larynx (voice box). -passageway for air and food -provides a resonating chamber for speech sounds -houses the tonsils participate in immunological reactions against foreign invaders."

nasopharynx, oropharynx, and laryngopharynx."

The pharynx can be divided into three anatomical regions:

outer circular layer and an inner longitudinal layer."

muscles of the entire pharynx are arranged in two layers:

"Nasopharynx"

superior portion of the pharynx, lies posterior to the nasal cavity and extends to the soft palate. It has five openings in its wall: two internal nares, two openings that lead into the auditory (pharyngotympanic) tubes, and the opening into the oropharynx.

"Oropharynx"

intermediate portion of the pharynx,

• lies posterior to the oral cavity and extends from the soft palate inferiorly to the level of the hyoid bone. -has both respiratory and digestive functions, serving as a common passageway for air, food, and drink."

"Laryngopharynx"

-inferior portion of the pharynx, begins at the level of the hyoid bone. At its inferior end it opens into the esophagus (food tube) posteriorly and the larynx (voice box) anteriorly.

"Larynx"

-short passageway that connects the laryngopharynx with the trachea. -lies in the midline of the neck anterior to the esophagus and the fourth through sixth cervical vertebrae (C4-C6).

"Wall of Larynx"

composed of 9 pieces of cartilage (thyroid cartilage, epiglottis, cricoid cartilage, arytenoid, cuneiform, and corniculate cartilages). -extrinsic muscles of the larynx connect the cartilages to other structures in the throat -intrinsic muscles connect the cartilages to one another."

"Cavity of the Larynx"

space that extends from the entrance into the larynx down to the inferior border of the cricoid cartilage. The portion of the cavity of the larynx above the vestibular folds is called the laryngeal vestibule. The portion of the cavity of the larynx below the vocal folds is called the infraglottic cavity."

"Thyroid Cartilage"

"Consists of two fused plates of hyaline cartilage that form the anterior wall of the larynx and give it a triangular shape."

"Epiglottis"

large, leaf-shaped piece of elastic cartilage that is covered with epithelium. The 'stem' of the epiglottis is the tapered inferior portion that is attached to the anterior rim of the thyroid cartilage."

"Cricoid Cartilage"

"A ring of hyaline cartilage that forms the inferior wall of the larynx. It is attached to the first ring of cartilage of the trachea by the cricotracheal ligament."

"Arytenoid Cartilages"

"Triangular pieces of mostly hyaline cartilage located at the posterior, superior border of the cricoid cartilage. They form synovial joints with the cricoid cartilage and have a wide range of mobility."

"Corniculate Cartilages"

"Horn-shaped pieces of elastic cartilage, are located at the apex of each arytenoid cartilage."

"Cuneiform Cartilages"

"Club-shaped elastic cartilages anterior to the corniculate cartilages, support the vocal folds and lateral aspects of the epiglottis."

"Vestibular Folds"

superior pair of folds in the mucous membrane of the larynx, also known as false vocal cords. -do not function in voice production, - important functional roles such as holding the breath against pressure in the thoracic cavity."

"Vocal Folds"

inferior pair of folds in the mucous membrane of the larynx, also known as true vocal cords. - principal structures of voice production.

"Intrinsic Laryngeal Muscles"

muscles attach to both the rigid cartilages and the vocal folds. When contract, they move the cartilages, which pulls the elastic ligaments tight, and this stretches the vocal folds out into the airways so that the rima glottidis is narrowed."

"Phonation"

"Air passing through the larynx vibrates the folds and produces sound by setting up sound waves in the column of air in the pharynx, nose, and mouth."

"Posterior Cricoarytenoid Muscles"

"When these muscles contract, they move the vocal folds apart (abduction), thereby opening the rima glottidis."

"Lateral Cricoarytenoid Muscles"

"When these muscles contract, they move the vocal folds together (adduction), thereby closing the rima glottidis."

"Pitch Control"

is controlled by the tension on the vocal folds. If they are pulled taut by the muscles, they vibrate more rapidly, and a higher pitch results. Decreasing the muscular tension on the vocal folds causes them to vibrate more slowly and produce lower-pitched sounds."

"Whispering"

"Accomplished by closing all but the posterior portion of the rima glottidis. Because the vocal folds do not vibrate during whispering, there is no pitch to this form of speech. However, we can still produce intelligible speech while whispering by changing the shape of the oral cavity as we enunciate."

"Laryngitis"

inflammation of the larynx that is most often caused by a respiratory infection or irritants such as cigarette smoke. causes hoarseness or loss of voice by interfering with the contraction of the folds or by causing them to swell to the point where they cannot vibrate freely."

"Cancer of the Larynx"

"Found almost exclusively in individuals who smoke. The condition is characterized by hoarseness, pain on swallowing, or pain radiating to an ear. Treatment consists of radiation therapy and/or surgery."

"Layers of Tracheal Wall"

"The layers of the tracheal wall, from deep to superficial, are the mucosa, submucosa, hyaline cartilage, and adventitia (composed of areolar connective tissue)."

"Mucosa of Trachea"

"Consists of an epithelial layer of ciliated pseudostratified columnar epithelium and an underlying layer of lamina propria that contains elastic and reticular fibers. It provides the same protection against dust as the membrane lining the nasal cavity and larynx."

"Cancer of Larynx"

"Found almost exclusively in individuals who smoke. The condition is characterized by hoarseness, pain on swallowing, or pain radiating to an ear. Treatment consists of radiation therapy and/or surgery."

"Trachea"

"A tubular passageway for air that is about 12 cm long and 2.5 cm in diameter. It is located anterior to the esophagus and extends from the larynx to the superior border of T5 vertebrae, where it divides into right and left primary bronchi."

Right main bronchus and left main bronchus

trachea divides into 2

"Right Main Bronchus"

is more vertical, shorter, and wider than the left one. It goes into the right lung. An aspirated object is more likely to enter and lodge in the right main bronchus than the left."

"Left Main Bronchus"

more horizontal and narrower than the right one. It goes into the left lung.

"Carina"

"An internal ridge formed by a posterior and somewhat inferior projection of last tracheal cartilage at point where trachea divides into right and left main bronchi.

• mucous membrane of is one of most sensitive areas for triggering a cough reflex."

"Bronchial Tree"

"The extensive branching from the trachea through the terminal bronchioles, which resembles an inverted tree. It contains about 23 generations of branching."

"Lobar Bronchi"

"Formed when the main bronchi divide upon entering the lungs. There is one for each lobe of the lung."

"Segmental Bronchi"

"Formed when the lobar bronchi continue to branch. They supply the specific bronchopulmonary segments within the lobes."

"Bronchioles"

"Formed when the segmental bronchi divide. They branch repeatedly, and the smallest ones branch into even smaller tubes called terminal bronchioles."

"Terminal Bronchioles"

"The smallest bronchioles which contain club (Clara) cells, columnar, nonciliated cells interspersed among the epithelial cells. They represent the end of the conducting zone of the respiratory system."

"Respiratory Bronchioles"

"Microscopic branches beyond the terminal bronchioles of the bronchial tree."

"Pleural Membrane"

-Each lung is enclosed and protected by a double-layered serous membrane . -superficial layer, called the parietal pleura, lines the wall of the thoracic cavity

• deep layer, the visceral pleura, covers the lungs themselves."

"Pleural Cavity"

-Between the visceral and parietal pleurae is a small space, which contains a small amount of lubricating fluid secreted by the membranes.

• pleural fluid reduces friction between the membranes, allowing them to slide easily over one another during breathing."

"Pleurisy"

"Inflammation of the pleural membrane, may cause pain due to friction between the parietal and visceral layers of the pleura. If inflammation persists, excess fluid accumulates in the pleural space, a condition known as pleural effusion."

"Pneumothorax and Hemothorax"

pleural cavities may fill w/air (pneumothorax=air), blood (hemothorax), or pus. Air in the pleural cavities may cause the lungs to collapse (atelectasis)."

"Lungs"

"Paired cone-shaped organs in the thoracic cavity. They are separated from each other by the heart and other structures of the mediastinum."

"Base of Lung"

"The broad inferior portion of the lung, is concave and fits over the convex area of the diaphragm."

"Apex of Lung"

"The narrow superior portion of the lung."

"Costal Surface of Lung"

"The surface of the lung lying against the ribs, matches the rounded curvature of the ribs."

"Mediastinal Surface of Lung"

"The mediastinal (medial) surface of each lung contains a region, the hilum, through which bronchi, pulmonary blood vessels, lymphatic vessels, and nerves enter and exit."

"Alveolar Sacs"

"The terminal dilation of an alveolar duct is called an alveolar sac and is composed of outpouchings called alveoli."

"Alveoli"

"Outpouchings from an alveolar sac. The wall of each alveolus consists of two types of alveolar epithelial cells. -Type I alveolar cells are simple squamous epithelial cells that form a nearly continuous lining of the alveolar wall. -Type II alveolar cells secrete alveolar fluid, which keeps the surface between the cells and the air moist."

"Surfactant"

"Included in the alveolar fluid, it is a complex mixture of phospholipids and lipoproteins. Surfactant lowers the surface tension of alveolar fluid, which reduces the tendency of alveoli to collapse and thus maintains their patency."

"Respiratory Membrane"

exchange of O2 and CO2 between the air spaces in the lungs and the blood takes place by diffusion across the alveolar and capillary walls, which together form the respiratory membrane."

1. A layer of type I and type II alveolar cells and associated alveolar macrophages that constitutes the alveolar wall

2. An epithelial basement membrane underlying the alveolar wall

3. A capillary basement membrane that is often fused to the epithelial basement membrane

4. The capillary endothelium

respiratory membrane consists of four layers:

"Coryza"

"Also known as the common cold, it is caused by hundreds of viruses, but a group of viruses called rhinoviruses is responsible for about 40% of all colds in adults. Typical symptoms include sneezing, excessive nasal secretion, dry cough, and congestion."

"Seasonal Influenza"

"Also known as flu, it is caused by a virus. Its symptoms include chills, fever (usually higher than 101°F = 39°C), headache, and muscular aches. Seasonal influenza can become life-threatening and may develop into pneumonia."

"H1N1 Influenza"

"Also known as swine flu, it is a type of influenza caused by a new virus called influenza H1N1. The virus is spread in the same way that seasonal flu spreads: from person to person through coughing or sneezing or by touching infected objects and then touching one's mouth or nose."

"Blood Supply to the Lungs"

"The lungs receive blood via two sets of arteries: pulmonary arteries and bronchial arteries. Deoxygenated blood passes through the pulmonary trunk, which divides into a left pulmonary artery that enters the left lung and a right pulmonary artery that enters the right lung."

"Bronchial Arteries"

which branch from the aorta, deliver oxygenated blood to the lungs. This blood mainly perfuses the muscular walls of the bronchi and bronchioles."

"Pulmonary Ventilation"

"-known as breathing, it is the flow of air into and out of the lungs.

• air flows between the atmosphere and the alveoli of the lungs

"Pressure Changes during Pulmonary Ventilation"

"Air moves into the lungs when the air pressure inside the lungs is less than the air pressure in the atmosphere. Air moves out of the lungs when the air pressure inside the lungs is greater than the air pressure in the atmosphere."

Ventilation-Perfusion Coupling

perfusion (blood flow) to each area of the lungs matches the extent of ventilation (airflow) to alveoli in that area.

Inhalation

Breathing in, achieved by increasing the size of the lungs.

Boyle's law

inverse relationship between volume and pressure. If the size of a closed container is increased, the pressure of the gas inside the container decreases.

Diaphragm

main muscle of inhalation, which when contracted causes it to flatten, lowering its dome. This increases the vertical diameter of the thoracic cavity.

External intercostals

muscle that when contracted, they elevate the ribs. This results in an increase in the anteroposterior and lateral diameters of the chest cavity.

Intrapleural pressure

pressure within the pleural cavity, which is the space between the parietal pleura and visceral pleura.

"Pressure changes in pulmonary ventilation"

"During inhalation, the diaphragm contracts, the chest expands, the lungs are pulled outward, and alveolar pressure decreases. During exhalation, the diaphragm relaxes, the lungs recoil inward, and alveolar pressure increases."

"Alveolar pressure"

"Air moves into the lungs when alveolar pressure is less than atmospheric pressure, and out of the lungs when alveolar pressure is greater than atmospheric pressure."

"Inhalation process"

"During inhalation, the diaphragm contracts and the external intercostals contract. The chest cavity expands, and the alveolar pressure drops below atmospheric pressure."