View
237
Download
1
Category
Tags:
Preview:
Citation preview
STRUCTURE Respiratory system contains: Upper respiratory tract. Lower respiratory tract.
Upper respiratory tract contains: The nose The nasal cavities Pharynx Larynx Upper trachea
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 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.
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.
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.
Recommended