RESPIRATORY SYSTEMJoe Pistack MS/ED

STRUCTURE Respiratory system contains: Upper respiratory tract. Lower respiratory tract.

Upper respiratory tract contains: The nose The nasal cavities Pharynx Larynx Upper trachea

STRUCTURE Lower respiratory tract: Lower trachea Bronchi Bronchioles Alveoli

THE NOSE AND NASAL CAVITIES Nose-includes an

external portion that forms part of the face.

Nasal cavities-separated into right and left halves by a nasal septum.

THE NOSE AND NASAL PASSAGES Air enters the nasal

cavities through two openings called nostrils.

Nasal hairs in the nostrils filter large particles of dust that would otherwise be inhaled.

THE NOSE AND NASAL PASSAGES Nasal conchae-

three bony projections appear on the lateral walls of the nasal cavities.

Support mucous membrane.

Contains blood vessels and mucous-secreting cells.

THE NOSE AND NASAL CAVITIES Paranasal sinuses: Maxillary sinuses Frontal sinuses Ethmoidal sinuses Sphenoidal sinuses

Mucous from the paranasal sinuses drain into the nasal cavity.

THE NOSE AND NASAL CAVITIES Deviated septum-

Nasal septum bends to one side or the other.

Obstructs flow of air, makes breathing difficult.

Surgical repair is called a septoplasty.

PHARYNX Pharynx or

throat-Located behind the oral cavity, between the nasal cavities.

Includes three parts:

Nasopharynx Oropharynx laryngopharynx

PHARYNX Nasopharynx-upper section.

Oropharynx-middle section.

Laryngopharynx-lower section.

Function of pharynx: Conducts food toward the esophagus. Functions as a passageway for both food

and air.

LARYNX Also called the

voicebox Three functions:

(1)Passageway for air during breathing

(2)Produces sound

(3)Prevents food and foreign objects from entering the trachea

LARYNX

Triangular structure made primarily of cartilage, muscles,and ligaments.

LARYNX Thyroid cartilage-largest of the

cartilaginous structures .

Protrudes in the front of the neck as the Adam’s apple.

Epiglottis-located at the top of the larynx, acts as a flap, covers the opening of the trachea during eating so that food doesn’t enter the lungs.

VOCAL CORDS

Folds of tissue composed of muscle and elastic ligaments covered by mucous membrane.

The space between the vocal cords is the glottis.

VOCAL CORDS False vocal cords-do

not produce sounds.

True vocal cords-produce sound, air flowing from the lungs through the glottis during exhalation causes the vocal cords to vibrateproducing sound

VOCAL CORDS The loudness of your voice depends on

the force with which air moves past the true vocal cords.

The pitch of your voice depends on the tension exerted on the muscles of the true vocal cords.

You form words with your pharynx, oral cavity, tongue and lip movement.

SWALLOWING Swallowing plays a key role in

preventing food or water from entering into the respiratory tubes.

Neurological patients who have difficulty swallowing are at risk for aspiration.

(entrance of food or water into the lungs)

TRACHEA Windpipe-tube 4

to 5 inches in length and 1 inch in diameter.

Extends from the lower edge of the larynx downward into the thoracic cavity where it splits into the right and left bronchi

TRACHEA Carina-point where

the trachea splits, at the manubriosternal junction (where the manubrium of the sternum meets the sternal body)

This area is very sensitive, touching during suctioning causes vigorous coughing.

TRACHEOSTOMY Insertion of a tube

through a surgical incision into the trachea below the level of an obstruction.

By passes the obstruction and allows air to flow through the tube into the lungs.

TRACHEA Lies in front of the esophagus, the food tube.

C-shaped rings of cartilage partially surround the trachea for its entire length.

The rings are open on the back side of the trachea so that the esophagus can bulge forward as food moves along the esophagus into the stomach.

Without the cartilaginous rings, the trachea would collapse and shut off air supply.

CARTILIGENOUS RINGS

BRONCHIAL TREE Consists of : Bronchi Bronchioles Alveoli

Resembles an upside down tree.

BRONCHI

Right and left primary bronchi are formed as the lower part of the trachea divides into two tubes.

BRONCHI Primary bronchi-

enter the lungs at a region called the hilus.

Primary bronchi branch into secondary bronchi, which branch into smaller tertiary bronchi.

BRONCHI Left bronchus is

narrower because the heart lies to the left side of chest.

Right bronchus is shorter and wider and extends downward in a vertical direction.

BRONCHIOLES The bronchi

divide repeatedly into smaller tubes called bronchioles.

Regulate the flow of air to the alveoli.

BRONCHIOLES Contraction of the

bronchiolar smooth muscle causes the bronchioles to constrict, this decreases the bronchiolar lumen and decreases the flow of air.

Relaxation causes the lumen to increase, thereby increasing the flow of air.

ALVEOLI Small grape-like

structures, tiny air sacs that form at the ends of the respiratory passages.

Function is to exchange oxygen and carbon dioxide across the alveolar-pulmonary capillary membrane.

ALVEOLI Certain respiratory diseases cause

thickening of the alveolar wall.

Results in slow exchange of gases.

Results in hypoxia, retained carbon dioxide, this results in acidosis ( disturbance in acid-base balance).

Ex. Emphysema, this may result in clubbing of the fingers and toes.

ALVEOLI Amazing Facts:

10,000 liters of air per day goes through our lungs - that’s 2650 gallons

There are about 300 million alveoli (300,000,000)

Have the surface area of a tennis court - that’s about 2800 square feet.

HYPOXEMIA Clubbing: Enlarged fingertips and toes. Changes in

thickness and shape of the nails.

Due to formation of additional capillaries in attempt to deliver oxygen.

LUNGS Two lungs: Located in the

pleural cavity. Extend from area

above the clavicles to the diaphragm.

Soft, cone-shaped, occupy most of the space in the thoracic cavity.

LUNGS Subdivided into

lobes: Right lung has

three lobes: superior middle inferiorLeft lung: superior inferior

LUNGS Upper, rounded

part is called , the apex.

The base rests on the diaphragm.

Amount of air lungs can hold depends on build, age, and physical condition.

PLEURA Pleura-lining of the

inner chest wall, continuous serous membrane.

Visceral-inner layer.

Parietal pleura-outer layer.

COLLAPSED LUNG Expanded lungs

normally fill the thoracic cavity.

Tendency of the lungs to collapse is due to two factors:

Elastic recoil Alveolar surface

tension

Negative intrapleural pressure is eliminated, lungs collapse.

ELASTIC RECOIL Lungs need to be expanded to function

properly.

Elastic recoil opposes lung expansion.

Negative intrapleural pressure must exceed the elastic recoil and surface tension.

Ex. balloon

SURFACE TENSION High surface tension within the alveoli is

favorable for a collapsed lung.

Surfactant decreases surface tension.

Problem with preterm infants, not enough surfactant is secreted so they have difficulty breathing. Rx. Steroids.

NEGATIVE INTRAPLEURAL PRESSURE

Intrapleural pressure remains negative when no holes exist in the chest wall.

When the lungs expand, the diaphragm contracts, the pull causes negative pressure.

Anything that collects in the intrapleural space can collapse the lung. Ex. blood, air, and drainage.

A knife wound would eliminate intrapleural pressure.

ATELECTASIS

RESPIRATION

Respiration includes:

(1)-ventilation or breathing

(2)-exchange of oxygen and carbon dioxide

(3)-transport of oxygen and carbon dioxide by the blood

VENTILATION Ventilation-movement of air into and out

of the lungs.

Two phases: Inhalation-breathing-in phaseExhalation-breathing-out phase

Respiratory cycle-one inhalation and one exhalation .

VENTILATION Dependent on Boyle’s law, “As volume

increases, pressure decreases; as volume decreases, pressure increases.”

Thoracic pressure decrease causes air to move through the nose and into the lungs.

Thoracic pressure increase causes air to move out of the lungs. When respiratory muscles relax, they decrease thoracic volume.

MUSCLES OF RESPIRATION

Change in thoracic volume is due to the contraction and relaxation of the respiratory muscles.

On inhalation-respiratory muscles, (the diaphragm and intercostal muscles) contract.

Diaphragm is the chief muscle of inspiration.

Accessory muscles of respiration-muscles of the abdominal wall and internal intercostal muscles.

EXCHANGE OF GASES

Exchange of gases occurs at two sites: (1)lungs (2)cells

In lungs, oxygen diffuses from the alveoli into the pulmonary capillaries. Carbon dioxide diffuses from the pulmonary capillaries into the alveoli.

In the cell, oxygen diffuses from the capillaries into the cells, carbon dioxide diffuses from the cells into the capillaries.

Blood transports oxygen and carbon dioxide.

LUNG VOLUMES Different volumes of air we breathe have

names.

Four pulmonary volumes: (1)-tidal volume (2)-inspiratory reserve volume (3)-expiratory reserve volume (4)-residual volume

A spirometer is used to measure pulmonary volumes.

LUNG VOLUMES Tidal volume-the amount of air moved in

and out of the lungs with each breath. Usually about 500ml.

Inspiratory reserve volume-in addition to the normal volume, any extra air that you can breathe in. Approximately 3000ml.

Expiratory reserve volume-the normal amount of air you exhale plus any extra, usually about 1100ml.

LUNG VOLUMES Residual volume-after forced exhalation,

about 1100ml of air remains in the lungs. The remaining air is the residual volume.

Residual air remains in the lungs at all times, even between breaths.

Anatomical dead space-some air that you inhale never reaches the alveoli, it is not available for gas exchange.

NORMAL BREATHING Normal breathing is rhythmic and

involuntary.

Normal respiratory rate is 12 to 20 breaths per minute in an adult.

In a child, normal respiratory rate is 20 to 40 breaths per minute.

Medullary respiratory control center-main control center for breathing, located in the medulla, sets the basic breathing rhythm.

RESPIRATION Pneumotaxic center and apneustic center-located

in the pons, modify and help control breathing patterns

Opioids, such as morphine, depress respiratory function, do not administer without checking respirations.

Hering-Breurer Reflex-reflex that prevents overinflation of the lungs.

Hyperventilation-increase in the rate and depth of respirations. Causes excess exhaling of carbon dioxide and produces hypocapnia (diminished carbon dioxide in the blood).

RESPIRATIONS

Hypoventilation:

Decrease in the amount of air entering the alveoli.

Causes insufficient amount of oxygen and excessive amount of carbon dioxide in the blood.

Causes are respiratory obstruction - lung disease, deformity of the chest, mucous plug.

VENTILATION Exhalation:

Occurs when the respiratory muscles relax, allowing the thorax to return to smaller, resting thoracic volume.

Muscles of respiration contract in response to stimulation of the phrenic and intercostal nerves.

Inhalation delivers fresh oxygen-rich air to the alveoli, and exhalation removes carbon dioxide-laiden air from the alveoli.

RESPIRATION The exchange of gases occurs at two sites: The lungs The cells

Gas exchange occurs in the lungs, specifically across the membranes of the alveolus and the pulmonary capillary.

Three conditions make alveoli suited for exchange: (1) Large surface area, (2)Thin alveolar and capillary walls, (3)Closeness of the alveoli to the pulmonary capillaries.

AS WE AGE Lung capacity decreases. Protective mechanisms of respiratory

disease decline. Number of alveoli diminishes resulting in

decreased oxygenation. Decreased oxygenation decreases the

amount of physical activity that the person is capable of.

Lungs show wear and tear from a lifetime of inhaling harmful substances such as pollens, pollutants, cigarette smoke.

RESPIRATORY TERMS apnea-temporary cessation of breathing.

Dyspnea-difficult or labored breathing.

Tachypnea-rapid breathing.

Eupnea-normal, quiet breathing.

Orthopnea-difficult breathing that is relieved by sitting-up position. Usually dyspnea is relieved with two pillows.

RESPIRATORY TERMS Cheyne-Stokes respirations-an

irregular breathing pattern characterized by a series of shallow breaths that gradually increase in depth and rate. A period of apnea lasting 10 to 60 seconds follows, the cycle then repeats.