29 - respiratory system Flashcards
(15 cards)
what is breathing induced by?
Pulmonary ventilation, or breathing, is induced by changes in the volume of the lungs and the air pressure within them. During normal inhalation the diaphragm and external intercostal muscles contract, and the ribcage elevates.
as volume in the lungs increases, what happens to air pressure in the lungs?
As the volume of the lungs increases, air pressure in the lungs drops below atmospheric pressure, and air rushes in. During normal exhalation, the muscles relax, the lungs become smaller, pressure inside them rises, and air is expelled.
what is Boyl’s law?
Boyl’s law explains this relationship between volume and air pressure:
- An increase in the volume of a container lowered the pressure of the air inside
- A decrease in the volume raises pressure in the reduced space
how does the body’s demand for more oxygen change normal breathing?
The body’s demand for more oxygen can change normal breathing to force breathing. Additional muscles increase the changes in volume of the thoracic cavity so that more air can pass in and out more rapidly.
what are the pulmonary ventilation structures?
In pulmonary ventilation, or breathing, air is inhaled and exhaled. Air moves in through the nasal and oral cavities, through the pharynx, larynx and trachea into the lungs and then moves back out again.
what are the muscles of inhalation?
Muscles of inhalation work to expand or shrink the lungs and create airflow. During normal inhalation, the diaphragm, and external intercostals contract. In forces inhalation, the sternocleidomastoid, scalenes, pectoralis minor, and serratus anterior also contract.
what are the muscles of exhalation?
During normal exhalation, the diaphragm and external intercostals relax. During forced exhalation, the internal intercostals, transversus thoracis, and abdominal muscles contract.
what is external respiration?
Inside the lungs, oxygen from the air is exchanged for waste carbon dioxide from the bloodstream. This process of external respiration takes place in hundreds of millions of microscopic sacs called alveoli.
Oxygen from inhaled air diffuses from the alveoli into the pulmonary capillaries surrounding them, and is pumped through the bloodstream.
Carbon dioxide from oxygen-depleted blood diffuses from the capillaries into the alveoli, and is expelled through exhalation.
what are the external respiration structures?
In external respiration, gases are exchanged between the lungs and bloodstream. Oxygen from inhaled air moves into the pulmonary vessels, and carbon dioxide moved out for exhalation.
what is Dalton’s law?
Gas exchange occurs in the lungs, as oxygen diffuses from alveoli into the bloodstream and carbon dioxide diffuses from the bloodstream into the alveoli. Dalton’s law explains that in a gas mixture, the pressure exerted by each gas is independent.
The gas mixture in the alveolus has a high oxygen partial pressure, while the partial pressure of oxygen in the surrounding pulmonary capillaries is low. For this reason, oxygen diffuses from the alveolus into the pulmonary capillary. Carbon dioxide diffuses out of the capillary and into alveoli for the same reason.
what is internal respiration?
The bloodstream delivers oxygen to cells and removes waste carbon dioxide through a process called internal respiration.
In the lungs, oxygen is absorbed into the erythrocytes in the blood stream. These cells, commonly called red blood cells, contain gas-transporting molecules called haemoglobin. Oxygen binds to these molecules. The oxygenated blood then moves through the vasculature. At the narrow capillaries within the body tissues, red blood cells release oxygen, which then diffuses through the capillary wall into tissues.
Meanwhile, the waste product carbon dioxide diffuses into the bloodstream, where it is carried inside red blood cells in the plasma. The deoxygenated blood travels through the vasculature and back to the lungs, where carbon dioxide is expelled from the body.
what are the internal respiration structures?
In internal respiration, gases are exchanged between the bloodstream and body tissues. Oxygen carried by arteries moves into cells, and waste carbon dioxide moves out into veins.
how is normal breathing regulated?
Respiration is an involuntary function. Nerve impulses transmitted by the pons and the medulla oblongata to respiratory rate. The rate of normal breathing is 12 to 15 breaths per minute. The body adjusts the rate and depth of normal breathing in response to metabolic needs.
what happens when the body needs more oxygen?
When the body uses more oxygen or holds too much carbon dioxide, sensors in the circulatory system called chemoreceptors send signals to the brain. The rate and depth of ventilation/breathing increases so that more gas can be exchanged. Involuntary breathing mechanisms can be overridden by the cerebral cortex. Actions, including talking, sneezing and coughing, can also alter breathing patterns for short periods of time.
what do chemoreceptors in the aortic arch and common carotid arteries do?
Chemoreceptors in the aortic arch and common carotid arteries detect changes in carbon dioxide and oxygen levels in the blood. They send signals up the valgus to the medulla oblongata, which adjusts the respiratory rate as needed.
