The Respiratory System: Yatziri Carmona (per.1) (Respiratory Physiology (4…
The Respiratory System: Yatziri Carmona (per.1)
Parts of the respiratory system
warms, moisturizes, and filters air entering the body before it reaches the lungs
paranasal sinuses: a group of four paired air-filled spaces that surround the nasal cavity
produce a mucus that moisturizes the inside of the nose. This mucus layer protects the nose from pollutants, micro-organisms, dust and dirt
The nose is the only external structure. It provides an airway for respiration, moistens and warms entering air, cleans inspired air, serves as a resonating chamber for speech, and houses smell receptors
the larynx is the voice box. It provides a patent airway, acts as a switching mechanism to route air and food into the proper channels, and voice production
pharynx: is part of the digestive system and the conducting zone of the respiratory system
divided into three sections: the nasopharynx, oropharynx, and laryngopharynx
trachea: a wide, hollow tube that connects the larynx (or voice box) to the bronchi of the lungs. It is an integral part of the body's airway and has the vital function of providing air flow to and from the lungs for respiration
bronchi: extensions of the windpipe that shuttle air to and from the lungs
highways for gas exchange; oxygen going to the lungs and carbon dioxide leaving the lungs through them
Oxygen enters the lungs as part of the air that we breathe. It goes to the blood vessels deep in the lungs and then on to all parts of our body. As our body uses oxygen, it makes a waste product called carbon dioxide. We get rid of carbon dioxide when we breathe out
the parietal pleura covers the thoracic wall and superior face of the diaphragm
the actual site of gas exchange
composed of the respiratory bronchioles , alveolar ducts, and alveoli, all microscoptic structures
The pulmonary veins convey the freshly oxygenated blood from the respiratory zone of the lungs to the heart.
consists of all the respiratory passageways from the nose to the respiratory bronchioles
nostrils of the nose, the larynx, pharynx, trachea, bronchi, and bronchioles—filters, warms and moistens air and conducts it into the lungs.
In healthy lungs, it is always lower than atmospheric pressure.If this pressure becomes equal to the atmospheric pressure, the lungs collapse.
the pressure in the pleural cavity, the intrapleural pressure (Pip), also fluctuates with breathing phases, but is always about 4 mm Hg less than Ppul.
As it increases over atmospheric pressure, air flows out of the lungs. Rises well over atmospheric pressure during a forceful cough
intrapulmonary (intra-alveolar) pressure (Ppul) is the pressure in the alveoli. Intrapulmonary pressure rises and falls with the phases of breathing, but it always equalizes with the atmospheric pressure eventually
The pressure of air outside the body
Vital capacity (VC)
is the total amount of exchangeable air. It is the sum of TV, IRV, and ERV.
Functional residual capacity (FRC)
represents the amount of air remaining in the lungs after a normal tidal volume expiration and is the combined RV and ERV
Inspiratory capacity (IC)
the total amount of air that can be inspired after a normal tidal volume expiration, so it is the sum of TV and IRV
is the sum of all lung volumes.
total lung capacity
Boyle’s law gives the relationship between the pressure and volume of a gas: At constant temperature, the pressure of a gas varies inversely with its volume.
Dalton’s law of partial pressures
the total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas in the mixture. Further, the pressure exerted by each gas—its partial pressure—is directly proportional to the percentage of that gas in the gas mixture.
when a gas is in contact with a liquid, the gas will dissolve in the liquid in proportion to its partial pressure. Accordingly, the greater the concentration of a particular gas in the gas phase, the more and the faster that gas will go into solution in the liquid.
nonrespiratory air movements occur whenever you cough, sneeze, cry, laugh, hiccup, or yawn. Some can be produced voluntarily, but some (such as sneezing and hiccups) are reflexive
physical factors influencing alveolar surface tension
alveolar surface tension
the gas exchanges that occur between blood and alveoli and between blood and tissue cells take place by simple diffusion. They are driven by the partial pressure gradients of O2 and CO2 that exist on the opposite sides of the exchange membranes.
Molecular oxygen is carried in blood in two ways: bound to hemoglobin within red blood cells and dissolved in plasma
4 respiratory volumes
The amount of air that can be inspired forcibly beyond the tidal volume (2100 to 3200 ml) is the inspiratory reserve volume (IRV).
the amount of air—normally 1000 to 1200 ml—that can be expelled from the lungs after a normal tidal volume expiration
During normal quiet breathing, about 500 ml of air moves into and out of the lungs with each breath. This respiratory volume is the tidal volume (TV)
Even after the most strenuous expiration, about 1200 ml of air remains in the lungs; this is the residual volume (RV), which helps to keep the alveoli open and prevent lung collapse
the three ways CO2 is transported in blood
About 70% of CO2 is transported as bicarbonate ion (HCO3−) in plasma. Just over 20% is transported bound to hemoglobin in the RBCs, and 7–10% is dissolved in plasma.
: As blood CO2 increases, blood pH decreases. This is because CO2 combines with water to form carbonic acid. (However, the change in pH in blood for a given increase in CO2 is minimized by other buffer systems.)
Which brain stem respiratory area is thought to generate the respiratory rhythm?
Answer: The ventral respiratory group of the medulla (VRG) is thought to be the rhythm-generating area.