most superficial region of the lower respiratory system. It consists of cartilage components held together by ligaments and muscles.
a tongue-shaped cartilage that serves an important function during swallowing. When you swallow, the epiglottis covers the passageway, or GLOTTIS, of the larynx preventing food and drink from traveling into the lungs. When we speak the epiglottis is raised, which is why we could swallow food “down the wrong hole” and choke when we try to talk and eat at the same time.
passageway of the larynx
the anterior wall of the larynx and serves as the attachment site for the epiglottis.
extends all the way around the larynx but is most prominent as the posterior wall.
- - mucosa lining of much of the larynx and trachea
- - mucosa contains cilia and numerous mucus-producing goblet cells. The mucus lining the lower respiratory tract acts like fly paper to trap dust and other debris brought into the respiratory tract in the air we breathe. The cilia then wave to move the dirty mucus upward to the pharynx, where it is swallowed down to the stomach.
commonly called vocal cords, are located in the glottis. They should not be confused with the ventricular folds found above the vocal folds. By adjusting the degree of tension in the vocal folds, we are able to produce various sounds.
PATHWAY OF AIR TO LUNGS
Inhaled air travels from the larynx through the TRACHEA, PRIMARY BRONCHUS (one enters each LUNG), SECONDARY or LOBAR BRONCHUS (one enters each LOBE of the lung), TERTIARY or SEGMENTAL BRONCHUS (one enters each BRONCHOPULMONARY SEGMENT of a lobe), and then into a BRONCHIOLE.
- - the major site of gas exchange.
- - only airway structures thin enough and with enough surface area to allow sufficient gas diffusion to sustain life.
the space between the PARIETAL PLEURA lining the thoracic cavity and the VISCERAL PLEURA covering the lungs.
pleural fluid trapped inside the pleural cavity has a pressure
Alveoli of your lungs are like lots and lots of tiny balloons filled with air. Like air inside a balloon, the air inside alveoli has a pressure. But, alveoli are like untied balloons.
- - air in the pleural cavity
- - occurs when air enters the pleural cavity through a chest wound such as a knife wound or a lung disease that creates lesions
- - The moment intrapleural pressure approaches 760 mmHg, equaling alveolar pressure, the lung is no longer pushed outward. When a lung is no longer kept inflated, it collapses
- - a lung is no longer kept inflated, it collapses
- - can only affect one lung
lungs are dragged outward as the thorax expands because pleural fluid keeps the lungs stuck to the thoracic wall. As the lungs assume a larger volume, alveolar air has more room to move, alveolar pressure drops to a level (758 mmHg) less than atmospheric pressure (760 mmHg). Air is always pushed from an area of higher pressure to an area of lower pressure. In this case, atmospheric air is pushed into the lungs
- - thoracic cavity decreases in size, which compresses the lungs into a smaller size
- - major force decreasing the size of our lungs during exhalation is their ELASTIC RECOIL tendency
- (1) a high number of elastic fibers between alveoli that make the lungs snap back to a smaller size after inhalation like a stretched rubber band springs back to its original size
- (2) alveolar fluid surface tension that constantly draws alveoli to their smallest possible dimension.
- - elastic fibers in the lungs deteriorate. The lungs lose much of their elastic recoil tendency and, instead of snapping to a smaller size like a stretched rubber band, the lungs stay expanded
- - has difficulty exhaling, not inhaling
the movement of air outside the body with air inside alveoli.
Each alveolus is densely covered with a network that bring blood into close proximity to the air inside alveoli.
diffusion of oxygen from alveolar air into pulmonary capillary blood and the diffusion of carbon dioxide from pulmonary capillary blood into alveolar air.
diffusion of oxygen from systemic capillary blood into tissue cells and the diffusion of carbon dioxide from tissue cells into systemic capillary blood.
all the metabolic reactions that occur inside tissue cells to produce ATP energy.
- - Within the medulla oblongata
- - sets the basic rhythm of quiet ventilation
stimulates the accessory muscles of forced exhalation. The added muscle action compresses the thorax more than in quiet exhalation, and additional air is exhaled.
shortens length of inhalations so the lungs do not take in too much air
increases the length of inhalations for the deep breaths needed during such times as when we are exercising.
uncontrollably take rapid, deep breaths
- - blood pH below 7.35
- - as blood carbon dioxide levels rise, so do hydrogen ion levels, and blood becomes more acidic.
- - inhibits nervous system activity by inhibiting the transmission of nerve impulses throughout the body
- - blood pH above 7.45
- - release so much carbon dioxide through the lungs that our blood level of carbonic acid can be drastically lowered
- - nervous system becomes overly excited. This can lead to extreme nervousness, and then muscle convulsions, including convulsions of the diaphragm, larynx, and bronchioles, preventing breathing
breathing becomes more slow and shallow
CARBONIC ACID-BICARBONATE BUFFER SYSTEM
- -resists shifts in blood pH
- - If blood hydrogen ion levels begin to rise, this buffer removes the hydrogen ions from plasma like a “hydrogen ion sponge”, raising blood pH. When hydrogen ion levels begin to fall, the carbonic acid-bicarbonate buffer releases hydrogen ions, lowering blood pH.
- 1. Diaphragm and external intercostals muscles contract
- 2. Thoracic cavity volume increases
- 3. Lung volume increases
- 4. Alveolar Pressure decreases below atmospheric pressure
- 5. Inhalation occurs as air flows from area of greater pressure outside body to area of lesser pressure inside alveoli
- 1. Diaphragm, external intercostal, and accessory muscles of inhalation contract
- 2. Thoracic cavity volume increases more than quiet inhalation
- 3. Lung volume increases more than quiet inhalation
- 4. Alveolar Pressure decreases much below atmospheric pressure
- 5. Greater volume of air inhaled into alveoli than quiet inhalation
- 1. Diaphragm and external intercostal muscles relax
- 2. Thoracic cavity volume decreases
- 3. Lung volume decreases
- 4. Alveolar Pressure increases above atmospheric pressure
- 5. Air exhaled from area of greater pressure inside alveoli to area of lesser pressure outside body
- 1. Diaphragm and external intercostal muscles relax and accessory muscles of exhalation contract
- 2. Thoracic cavity volume decreases more than quiet exhalation
- 3. Lung volume decreases more than quiet exhalation
- 4. Alveolar Pressure increases much above atmospheric pressure
- 5. Greater volume of air exhaled out of alveoli than quiet exhalation