Name: ____________________________________
The Respiratory System Notes
Functions of the Respiratory System:
The main functions of the respiratory system are ___________ __________________________ and ___________
________________________________.
Structure:
The organs of the respiratory system can be divided into an ________________ respiratory tract, containing
the _____________, nasal cavity, paranasal sinuses, and _______________________, and a ___________________
respiratory tract, which includes the ________________, trachea, bronchial tree, and _________________.
Nose/Nasal Cavity:
The nose _______________________ , ______________ , and _______________________________ air. The nose has two
openings in which air can enter and leave the nasal cavity called _____________________________.
The ____________________ ______________________ is the hollow space behind the nose. The ____________________
_______________________ is composed of bone and cartilage, and divides the nasal cavity into right and left
portions. ______________________ ___________________ are bones that curl out from the lateral walls of the nasal
cavity on each side, dividing the cavity into ______________________________. The nasal conchae also support the
mucous membrane that lines the nasal cavity and helps increase its surface area.
The mucous membrane contains ___________________________________ ciliated epithelium that is rich in mucussecreting goblet cells. It also includes a network of blood vessels and as the air passes over the
membrane, heat leaves the blood and warms the air, adjusting the air’s temperature to that of the body.
_____________________________ air is moistened as water evaporates from the mucous lining. The sticky mucus
that the mucous membrane secretes entraps dust and other small particles entering with the air.
Pharynx/Larynx:
The pharynx or “________________” is located behind the oral cavity, nasal cavity, and the larynx. It is a
passageway for food traveling from the oral cavity to the ______________________________ and for air passing
between the nasal cavity and the larynx. It also helps to produce sounds of _________________.
The larynx is an _____________________________________ in the airway at the top of the trachea and below the
pharynx. Its function is to conduct air in and out of the trachea and prevent foreign objects from entering
the trachea. The larynx houses the ____________________ ___________________.
The larynx is composed of a framework of muscles and cartilages bound by elastic tissue. The largest of
the cartilages are the thyroid (__________________ _________________), cricoid, and epiglottic cartilages.
Inside the larynx, two pairs of horizontal _____________________ _________________ composed of muscle tissue
and connective tissue with a covering of mucous membrane extend inward from the lateral walls. The
upper folds are called the ______________ vocal cords because they do not produce sound. The lower folds of
muscle tissue are the _______________ vocal cords. Air forced between these vocal cords causes the cords to
vibrate side to side, which generates ________________ _______________.
Trachea:
The trachea or “__________________________” is a flexible, cylindrical tube about 2.5 centimeters in diameter
and 12.5 centimeters in length. It extends downwards anterior to the esophagus and into the thoracic
cavity, where it splits into right and left bronchi.
A ciliated mucous membrane with many goblet cells lines the trachea’s inner wall. This membrane filters
________________________ air and moves entrapped particles upwards into the ____________________, where the
mucous can be swallowed.
Within the tracheal wall are about 20 C-shaped pieces of hyaline cartilage. The open ends of these
incomplete rings are directed posteriorly. They prevent the trachea from _______________________________ and
blocking the airway.
Bronchial Tree:
The bronchial tree consists of ___________________________ airways leading from the trachea to the air sacs of
the lungs. Its branches begin with the right and left primary bronchi.
Each primary bronchus divides into secondary bronchi, into tertiary bronchi, then into finer tubes.
Among the smaller tubes are _______________________________________, that divided into terminal bronchioles,
respiratory bronchioles, and finally into alveolar ducts. These ducts lead to alveolar sacs, which lead to
microscopic air sacs called _____________________.
Lungs:
The lungs are soft, spongy, __________-shaped organs in the thoracic cavity. The _______________________________
separates into right and left medially, and the diaphragm and thoracic cage encloses them.
A layer of serous membrane, called the __________________ pleura, firmly attaches to each lung surface and
folds back to become the parietal pleura. The ________________________ pleura forms part of the mediastinum,
and lines the inner wall of the thoracic cavity. The space between the parietal and visceral pleura is called
the ________________ _________________________.
The right lung has three lobes and the left has two.
Breathing Mechanisms:
__________________________ pressure due to the weight of air is the force that moves air into lungs. If the
pressure inside the lungs and alveoli ________________________, atmospheric pressure will push outside air
into the airways. This is what happens during inspiration.
The lungs and thoracic wall contain considerable _____________________ tissue, and lung expansion during
inspiration stretches the tissue. As the diaphragm __________________, it compresses the abdominal organs
beneath it. Expiration is due to elastic recoil of the lung tissues and the abdominal organs.
Control Breathing:
Normal breathing is a rhythmic, involuntary act, however the respiratory muscles are under voluntary
control.
Groups of neurons that comprise the respiratory center in the brainstem control both inspiration and
expiration.
The medullary rhythmicity area includes two neuron groups that extend the length of the medulla
oblongata. They are the dorsal respiratory group and ventral respiratory group. The neurons in the
pneumotaxic area of the pons continuously transmit impulses that inhibit the inspiratory bursts
originating from the dorsal respiratory group.
Gas Exchange:
Alveoli are microscopic air sacs clustered at the _______________ ends of the narrowest respiratory tubes
(the ____________________ ducts). Each alveolus consists of a tiny space within a thin a wall that separates it
from _______________________ alveoli. Thin, fused basement membranes separate the layers of these flattened
cells, and in the spaces between the cells are _________________ and ___________________________ fibers that
support the alveolar wall. At least two thicknesses of epithelial cells and a layer of fused basement
membranes separate the air in an alveolus from the blood in a capillary. These layers comprise the
respiratory membrane across blood and alveolar air exchange gases.
The amount of pressure each gas contributes is called the ___________________ ______________________ of that gas
and is proportional to its ________________________________. Each gas diffuses between blood and its
surrounding from areas of _________________ partial pressure to areas of lower partial pressure until the
partial pressures of the two regions reach _______________________________.
Because of the difference in these partial pressures, ______________________ ____________________________ diffuses
from blood. Thus _______________________ diffuses from alveolar air into ________________, and blood leaves the
lungs
Gas Transport:
Almost all oxygen that blood transports binds the __________– containing protein ____________________________
in red blood cells. The remainder of oxygen is dissolved in ___________________.
In the lungs where the Po2 is relatively ____________, oxygen dissolves in blood and combines rapidly with
the iron atoms of the hemoglobin, forming _______________________________. The chemical bonds between
oxygen and hemoglobin molecules are unstable and as the Po2 decreases, __________________________
molecules release oxygen, which __________________ into nearby cells. Several other factors affect how much
oxygen oxyhemoglobin releases. More oxygen is _______________________ as the blood concentration of
___________________ _____________________ increases, as blood becomes more _______________, or as blood
______________________________ increased. More oxygen is released to skeletal muscles during
__________________________ _________________________________.
Asthma:
_____________________ is a chronic disease involving the airways in the lungs. These airways, or
____________________________ _______________, allow air to come in and out of the lungs.
About 1 in 12 or 8% of the population experiences asthma. Asthma is believed to be caused by a
combination of ________________________________________ and __________________ factors.
Those with asthma may experience _____________________ and ___________________________ airways, and
tightening of the _________________________ around the airways. This can make it difficult to breath.
Some symptoms are coughing, wheezing, ______________________ of breath and/or ______________ _____________.
Individuals who only experience symptoms of asthma when they exercise have ______________________ ________________________ _________________________________________ (EIB).
_______________________ asthma impacts millions of children. In fact, the majority of children who develop
asthma do so before the age of _________.
Though asthma cannot be prevented, there are many ways of treating it and keeping it under control.
Some ways include knowing your _______________ ______________________, taking asthma __________________________
as prescribed, as well as ________________________ your asthma and recognizing early sign that it may be
getting _______________________.
Bronchitis:
Bronchitis is the inflammation of the lining of the bronchial tubes. Bronchitis may be either _______________
or ______________________.
__________________ bronchitis is very common. ______________ bronchitis is more serious and is a
___________________ irritation or ___________________________ of the lining of the bronchial tubes- often due to
smoking.
Acute bronchitis, also known as a ______________ cold, usually improves within a week without lasting
effects. If there are repeated bouts of bronchitis, then it may be chronic bronchitis, which requires
______________________ attention. Chronic bronchitis is one of the conditions of chronic
_______________________________ _________________________ disease (COPD).
Symptoms of both acute and chronic bronchitis include: ___________________________ cough, wheezing, sore
throats, body aches, _________________________________, and headaches (to name a few).
Though prevention is not always possible, there are some measures that can help to reduce the risk. Do
not smoke, and avoid _______________ ______________________________ such as smoke, dust, fumes, vapor, and air
pollution. Be sure to wash hands frequently to limit exposure to germs and bacteria, as well as get a flu
and pneumonia ____________________________.
Many cases of acute bronchitis go away without any specific treatment, but there is no cure for chronic
bronchitis. To keep bronchitis symptoms under control and relieve symptoms, doctors may prescribe:
cough medicine, bronchodilators, anti-inflammatory medications, ___________________ ________________________,
pulmonary rehabilitation programs, or ____________________________________.
Lung Cancer:
Lung cancer is the ____________________________ growth of abnormal cells in one or both lungs.
_____________________ lung cancer originates in the lungs, while _______________________ lung cancer starts
somewhere else in the body and reaches the lungs.
Symptoms of primary lung cancer include: coughing, pain in the chest, shoulder, or back, shortness of
breath, ____________________ in voice or being hoarse, and recurrent lung problems such as
_________________________ or pneumonia. Symptoms of secondary lung cancer includes _________ of
____________________, muscle wasting, fatigue, headaches, ___________ _________________________ and neurological
symptoms such as unsteady gait or ____________________ ___________.
The main way to prevent lung cancer is to abstain from smoking and avoid secondhand smoke.