Biology 30SThe Respiratory System

Unit Four

Objectives - By the end of this unit students will be able to:

Differentiate between internal and external respiration. Identify the structure and function of the respiratory system. Compare the mechanics of inspiration to that of expiration. Describe the interaction between the respiratory system and the circulatory system. Describe the role of hemoglobin in respiration. Describe the defense mechanisms of the respiratory system.

Key themes and concepts in this unit:

The respiratory system exchanges carbon dioxide and oxygen with the environment Gas exchange depends on diffusion through the liquids surrounding cells. The rate of

diffusion increases as surface area becomes larger. Respiration involves specialized exchange surfaces that are often kept moist and housed

in protective structures. Oxygen in human lungs diffuses into capillaries, where it is taken up by hemoglobin. The

circulatory system then carries the oxygen throughout the body, where the gas diffuses into cells.

Breathing rate and depth are mostly involuntary and are controlled by nerves that detect the amount of carbon dioxide in the blood.

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The Importance of Respiration

Humans can survive for weeks without and for days without ; they can survive only a few minutes without .

Cells need oxygen to release energy from food. Without this energy, cells would not be able to carry out their main functions.

The process of _____________ helps ensure that the body gets the energy it needs for its functions. Respiration involves the ____________________ and _________________ of air, the exchange of gases between cells and the environment surrounding them, and the chemical reactions in which oxygen is used to release energy from food.

Respiration will be discussed in two ways: _________ respiration and _____________ respiration.

Although animal respiratory systems are diverse they share three features that facilitate diffusion of gases:

1. The respiratory surface must remain ______________ , because gases must be dissolved in water when they diffuse into or out of cells.

2. Cells lining the respiratory surfaces are very ________________ , a feature that facilitates diffusion of gases through them.

3. The respiratory system must have a large ___ _________ in contact with the environment to allow adequate gas exchange.

External Respiration

External respiration is the process in which the exchange of oxygen and carbon dioxide takes place between the ___________________ and the ________________________________organs.

External respiration is the processes by which external air is drawn into the body in order to supply the lungs with oxygen, and (used) air is expelled from the lungs in order to remove carbon dioxide from to body.

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Diagram outlining the Respiratory Structures

1. ____________________

2. ____________________

3. ____________________

4. ____________________

5. ____________________

6. ____________________

7. ________________________

8. ________________________

9. ________________________

10. ________________________

11. ________________________

12. _______________________

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Respiratory Structures and Functions

Nasal Cavity

Respiration begins when we inhale air. Respiration therefore begins at the ______________ cavity.

This structure is separated from the mouth cavity below it by a bony platform which forms the palate of the mouth. Extending into the nasal cavity are _____ bones, which help to increase the amount of surface area in the nose.

In the nasal cavity air is , , and before it is passed down into the lungs.

The air is warmed by contact with the many surfaces of the cavity, for the lining tissues are well supplied with ______ filled with warm blood.

The greater the ______ ____ that is in contact with the air, the more efficiently the warming is accomplished.

This is the value of the turbinate bones. On a cold day, the blood vessels in the skin covering the turbinate bones are capable of warming the temperature of air from ____ to almost _ temperature by the time that the air has entered the respiratory passages.

Moisture is supplied from secretions of the ________ tissue in the nostrils. The cells of these tissues also produce _____ which, together with the many _____ (small hair-like structures), aids in trapping ___ and other fine particles in the air.

Pharynx

The ____________________ forms a tube common to both the respiratory and digestive systems.

It starts at the back of the nasal cavity and extends down to the larynx (voice box). The upper part is the _______ ___ pharynx and is covered with ciliated epithelial

cells that trap the fine particles in the air. It also contains the ___________ and ____ ______ , which consist of a

mass of lymphoid tissue. Sometimes, especially in young children, they become infected and enlarged and may interfere with breathing or swallowing. The individual then breathes primarily through the mouth, which prevents the nasal chamber from cleaning, moistening, and warming the air that enters. In some severe cases of enlarged tonsils it is considered worthwhile to have them ______ ___ removed.

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The second portion of the pharynx, the _________ pharynx, lies behind the mouth cavity and forms a passageway for both food and air. Its walls are lined with epithelial cells which can stand up to the rough wear and tear of food passing through.

This tough lining extends into the last portion of the pharynx, which divides into two tubes: the _____ for carrying food, and the ___ for delivering air.

Larynx

The ____ is a boxlike structure located at the opening of the respiratory passageway. It is formed by several pairs of cartilage.

The largest of these, the __ cartilage, forms

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the framework of the Adam's apple. Above this is a leaf-shaped flap that forms the . The epiglottis seals the glottis, opening into the respiratory tract, thereby preventing the passage of into the lungs while swallowing.

The larynx contains two flaps of cartilage, controlled by muscles, the _____________ cords.

o As we speak, air passes out of the lungs and through the larynx. It causes these cords to and produce sounds, in much the same way as we can make a blade of grass produce sounds when we hold it tightly between our thumbs and blow on its edge.

o The ________ of the sounds made by the vocal cords can be changed by tightening or loosening the muscles that hold the cords in place.

o The thickness and length of the cords also affect the quality and pitch of the sounds produced.

o As sounds pass through the mouth, they are _____________ by the shape of the mouth and the position of the tongue into words that we can recognize.

Trachea

The is a tube, about 12 cm in length, which extends from the larynx into the thorax (chest cavity), where it divides into two smaller tubes, the right and left ___________________.

The trachea is constructed of smooth muscle in which C-shaped rings of cartilage are embedded. The rings are not quite complete at the back where the trachea is loosely attached to the .

When food is swallowed, the esophagus expands against the trachea. The rings serve primarily to keep the trachea from collapsing if there are pressure changes in the tube. The rings ensure that the trachea is always .

Bronchi and Bronchioles

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The right and left bronchi are also supported by small rings of cartilage. These tubes, in turn, branch into smaller tubes, forming what is often called the _____________________. The smallest branches are called ______ , which lack cartilage. They become smaller and smaller in diameter and more numerous, spreading through the entire lung tissue. The bronchial tree terminates with the _____ which lead into tiny chambers where gas exchange takes place. These chambers, or air sacs, called the _______________ . Each lung consists of more than 100 million alveoli.

Many of the epithelial cells that line the walls of most of the respiratory passages-nasal cavity, trachea, bronchi, and bronchioles-secrete __________ , and many of the _____________ and other small particles that escape entrapment by the nasal hairs become caught in this mucus.

The cells also are equipped with __________, microscope hair-like projections that beat upwards at the rate of about _______________ second.

o This action moves the mucus upward to where it can be _____________ to the stomach, in which most of the bacteria are destroyed, or it can be discharged by coughs and sneezes, thus ridding the body of potentially ________________ material.

o This is not always successful. Consequences can be seen in those with lung cancer and emphysema and of persistent cigarette smokers. ________________ paralyses the cilia and decreases their efficiency.

Lungs

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Each bronchus with all its bronchioles, alveolar ducts, and alveoli is called a ___________ . The lungs have no _____________. They are elastic, however, and can respond passively to the action of the ribs muscles and the diaphragm.

In humans there are two lungs, one fitting snugly into each side of the chest. The right lung, somewhat larger than the left, has lobes: upper, middle, and lower. The left lung has lobes: upper and lower and shares some of its space with the heart. The heart lies between the lungs. The lungs are well protected by the surrounding ribs, sternum, and spine. The base of each lung lies in contact with the _________________and the top of each lung reaches just above the clavicles.

The lungs are contained within the ____ , two membranous sacs which surround the lungs. The outer membrane, the ____ pleura, lines the inner surface of the chest wall and covers the upper surface of the diaphragm. The inner membrane, the _____ pleura, adheres to the surface of the lungs.

These membranes are so close together that only a very thin film of fluid, the fluid, separates them. The pleura help to isolate each lung, and the film of fluid has a lubricating function. It reduces the _______________ produced when the lungs move against the walls of the thoracic cavity.

Because two smooth surfaces adhere closely together when there is a film of moisture between them, when the rib cage during inhaling it pulls the lung wall with it. If you take two glass slides, wet them, and place the moistened surfaces together, they will be quite difficult to separate. This same action "____________" the lungs to the walls of the rib cage.

Practice: Respiration Matching

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Mechanics of Breathing

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The diffusion of oxygen from the _____ into the nose and throughseveral parts of the respiratory system to the alveoli would be too slow to supply a large, active organism with enough oxygen for its needs. Neither could diffusion rid the body of waste __ rapidly enough. The forcing of air into and out of the lungs by _____ movements hastens the exchange of gases with the environment.

Ordinarily breathing movements are ________________ ; they occur without much thought.

o They continue when a person is asleep or unconscious. This is necessary because the body does not store ____ , and more than momentary cessation of breathing can be lethal.

o It is possible to exercise _____ control over breathing. A person can hold his breath, or breathe more deeply or more shallowly than usual, but he soon tires of this, and involuntary control takes over.

One large muscle, the _____ , lies slightly above the waistline and separates the thoracic cavity from the abdominal cavity. Only a few structures pierce this muscle, the esophagus and some of the major blood vessels. All of these make a tight fit, and the separation of thoracic and abdominal cavities is complete.

o The diaphragm is not flat, but _________ , bulging upward into the thoracic cavity.

o When it contracts, the diaphragm flattens somewhat.

o Acting in unison with the diaphragm are the _______ , which are attached to the 12 pairs of ribs encircling the thorax. At the same time that the diaphragm contracts, the rib muscles contract also, moving the ribs slightly _____ and ______ .

o These actions __________ the volume of the chest cavity.

Inhalation

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o As the thorax expands, the parietal pleura, which is firmly attached to the thoracic wall and diaphragm, moves __ and __ with them.

o Because the intrapleural fluid does not expand, it moves with the parietal pleura and brings with it the pulmonary pleura, which is firmly attached to the lung.

o This causes the elastic lungs to expand and the air pressure in them. Because the air in the lungs is in direct communication with the external air, the difference in pressure cannot be maintained, and air moves in through the nose and proceeds to the lungs.

o This action is called an or of air.

Exhalation

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o Reversing the steps of an inhalation produces an ______ . When the diaphragm relaxes, it assumes its maximum curvature and pushes _____________ . At the same time, the intercostal muscles relax, allowing the ribs to move _______ and ____________________.

o Both of these movements push against the parietal pleura. Because the intrapleural fluid is not compressible, the force is transmitted to the pulmonary pleura and the lungs.

o The lungs _____ in size, and the air pressure within them rises above that of the external air.

o This forces air out of the lungs in an expiration or _________________ of air.

Inhaled vs. Exhaled Air

Inhaled Air Exhaled Air

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Oxygen Concentration 21 % 16 %

Carbon Dioxide Concentration

0.04 % 5 %

Nitrogen Concentration 78 % 78 %

Dryness Drier Moist

Temperature Colder or Warmer than 37 C Warm (close to 37 C)

Cleanliness Dirtier *Cleaner (filtered)

Air is cleaned (filtered), moistened and warmed as it passes through the nasal or oral cavity, but to a greater degree by the nasal cavity because of the increased surface area created by the turbinate bones. The skin (epithelium) lining the oral or nasal cavity is filled with blood vessels (capillaries) and covered in cilia and mucus. The cilia and mucus together trap particles that are in the air (smoke, dust, etc..), the mucus consists of a large amount of water which is absorbed by the incoming air, and the blood gives off heat to the incoming air. Because the turbinate bones create a larger surface area, all of these actions occur more quickly when air passes through the nasal cavity.

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*exhaled air may contain bacteria or

viruses

Capacity of the Lungs

A singer with a well-trained voice can hold a single note for over 30 seconds. To do this, the singer must be able to hold a relatively large amount of air in his or her lungs and release it in a slow, controlled manner. This ability is determined, in part, by the singer's vital capacity.

A person's ________ is the maximum amount of air the person can forcibly exhale after the largest possible inhalation of air. Vital capacity is also measured as the sum of three volumes of air:

i. The ______ volume is the amount of air inhaled or exhaled during normal, quiet breathing.

ii. The _______ reserve volume is the amount of air that can be forcefully inhaled after normal inhalation.

iii. The ______ reserve volume is the amount of air that can be forcibly exhaled after normal exhalation.

Spirometer

Spirometry is a _______________ breathing test that determines how well a person’s ___________ work. It is done with a device called a spirometer. A spirometer measures the amount of air a person can ______________ and __________________ they can blow the air out of their lungs.

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This device can detect a change in a person’s ability to breathe even before they do. It takes only a couple of minutes; no needles are involved; and it is not painful.

o The person being tested is asked to take in a ________________ and then seal his or her lips around the mouthpiece of the spirometer.

o The person will then have to blow out as __________________ as possible for at least six seconds, which is the approximate time it takes for normal lungs to empty. A nose clip may be applied to ensure no air escapes from the nose.

o This routine will be repeated at least three times to ensure that the test is done correctly and provides accurate results.

Spirometry is an effort dependent test and some people may become tired, but this is expected.

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Practice: The Mechanics of Breathing

1. Why do we breathe?

i)

ii)

iii)

2. Define:

Inhalation:

Exhalation:

3. What happens in the following areas when we breathe:

Inhalation Exhalation

Rib Cage

Intercostal Muscles

Pleura

Diaphragm

Lung Volume

Lung Pressure(and what happens to air)

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4. What is the composition of inhaled air? Exhaled air?

5. When exhaling the composition of oxygen is ______________ while the composition of carbon dioxide is ______________. Therefore our bodies are keeping some of the _____________ and replacing it with __________________. Also our bodies are giving off substantial amounts of ____________.

6. Explain how the lung/alveoli/capillaries make it easy for the diffusion of respiratory gases.

7. Under normal conditions, your regular breathing does not use up the full capacity of your lungs. As your body’s needs increase, such as when you exercise, the volume of air drawn in can also increase. The different volumes of air drawn in or pushed out by the lungs are:

Tidal Volume:

Inspiratory reserve volume:

Expiratory reserve volume:

Vital Capacity:

Residual Volume:

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Homeostasis

Homeostasis is the maintenance of a internal environment, despite external changes. The ability of the body to adjust and maintain the levels of oxygen and carbon dioxide is an example of homeostasis.

Breathing movements are controlled by ______ and not by the ________ themselves. The muscles are stimulated by ________ from the brain, which in turn is influenced by nerves that send impulses to the brain, informing it whether an inspiration or an expiration has just occurred. This system of brain, nerves, lungs, and muscles constitutes one of the many _____________________ mechanisms that maintain homeostasis in the human body.

The respiratory center of the brain (located in the medulla oblongata) is connected to the respiratory muscles (diaphragm and intercostal muscles) by ___ neurons that transmit impulses from the respiratory center to the muscles.

A set of ____ neurons conducts impulses from the lungs to the respiratory center.

At one moment the respiratory center may send a nervous impulse to the respiratory muscles that causes them to contract. This inflates the lungs in an inspiration.

The expansion of the lungs initiates impulses in the sensory neurons that extend from the lungs to the brain.

These impulses inhibit the breathing center, which then ceases to send it impulses to the respiratory muscles.

No longer stimulated, these muscles relax, and the lungs deflate in an expiration.

The deflated lungs cease stimulating the sensory neurons, and these cease sending impulses to the respiratory center of the brain.

No longer inhibited, the respiratory center once again sends out nervous impulses that stimulate the respiratory muscles, and the process repeats.

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Control of the Breathing Rate

Most of the time, breathing movements supply ___ as rapidly as the body needs it and removes ____ as fast as it is formed. Occasionally carbon dioxide may begin to accumulate in the blood or oxygen concentration may fall (two changes that often occur simultaneously). Either of these conditions ____ the rate and/or the depth of breathing, but the body seems to be more sensitive to the carbon dioxide concentration in the blood than to the oxygen concentration.

Breathing rate is mainly controlled by the respiratory center in the brain which monitors the carbon dioxide level in the ____ . The oxygen level is monitored by centers in the aorta and the common carotid arteries. The change in breathing speeds up the ______ of carbon dioxide from the blood and brings oxygen to it more rapidly.

Carbon dioxide dissolved in the blood reacts with water and forms ____________ , which ionizes to bicarbonate ion and hydrogen ion:

CO2 + H2O ---------> H2CO3

H2CO3 --------> HCO3 + H+

As more carbon dioxide enters the blood, the ion concentration rises. It is believed that the high concentration of hydrogen ion rather than the dissolved carbon dioxide gas stimulates breathing.

The high hydrogen ion concentration in the blood stimulates the respiratory center in the brain, which then sends impulses to the respiratory muscles and the breathing rate is ________________________.

Neurons with endings in the aorta and the common carotid arteries are sensitive to oxygen concentration.

These neurons monitor the blood continuously, and when the oxygen concentration begins to fall, they stimulate the respiratory center in the brain.

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Effects of Environment on Breathing Rate

If you have ever hiked in the high mountains, you have probably noticed how much and you breathe at higher elevations than at lower elevations. That is because there is oxygen in the air at higher elevations than at lower elevations. You need to take in more air to obtain the same amount of oxygen as at lower elevations.

People native to high altitudes have more alveoli and blood vessels in their lungs than people native to low altitudes. They also have a higher red blood cell count (70% of the blood volume instead of the normal 45 to 50%).

The effect of altitude on gas exchange:

As altitude increases, air pressure decreases. This is because air is less dense because the pull of gravity is less the higher you go. This means that there are ____________________________ (including less oxygen) the higher you go because the particles are _______________________. That being said, if a person goes hiking up a mountain that is higher than 10,000 feet above sea level, the air still contains 21% oxygen – there are still more than enough oxygen molecules to feed their body, but the problem is that those oxygen molecules can’t get into the person’s body. This is because at high altitudes there isn’t enough _______________________________ in order to push the oxygen from the lungs across the air sacs, blood vessels and cell membranes into the cells where the oxygen is needed. Therefore, if a person (or another large animal) goes to altitudes higher than 10,000 feet above sea level, they must have a _____________________________________(from a tank and mask) or be in a pressurized airplane in order to have the oxygen pushed into their cells.

High Altitude Training

Some elite athletes will travel to places with higher elevations (ex. Denver Colorado is a mile above sea level) in order to ____________________________________. When exercising at higher altitudes, the athlete’s body will at first experience breathing and heart rates that are __________________________. Eventually their body will adapt to the higher altitude by the ______________________________ so that breathing rates can return to the normal 14-20 breaths per minute. Additionally __________________________________________ around the air sacs in order to accommodate a faster gas exchange and more red blood cells will be added to the blood stream to facilitate a greater oxygen carrying capacity. Once these physiological adaptations have been acquired, the athlete will return to compete at lower altitudes where their body will be able to ______________________________________ and thus be able to generate ATP energy at a faster rate, thus increasing their performance in their sport.

Gas Exchange in the Lungs

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As was discussed previously, the trachea forks into right and left bronchi, one leading to each lung. Each bronchus, in treelike manner, branches into smaller tubes, the bronchioles, which divide repeatedly into alveolar ducts. These ducts end in numerous grapelike clusters, the alveolar sacs, each of which contains several pockets, the _________________. Although the alveoli of the lungs are small, they are so numerous that if they were to be opened up, their total surface area in an adult man would be 100 square meters, the size of a tennis court perhaps. It is across these 100 square meters of delicate alveolar surface that all our oxygen is .

A network of surrounds each alveolus. Their thin walls, like the alveolar walls, are only one cell thick. Thus the blood passing

through the capillaries is separated from the air in the alveolus by only two cells. At this point, the partnership between the respiratory system and the circulatory system

comes into effect. The respiratory system has brought oxygen molecules to the exchange site in the

alveoli. Now, oxygen will across the membranes, enter the bloodstream and be transported to the and , which require oxygen for their activities. Carbon dioxide, a waste product of cellular respiration, will diffuse into the alveoli and will be ____________________ from the body.

**Gas exchange in an alveolus takes place between capillary walls and the moist membrane of the alveolus.

The air we breathe into the alveoli is made up of nearly 80% __ , which the body cannot use and therefore it is exhaled. About 18% to 20% of the air is ____ ,

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which is a much higher concentration than that found in the blood. Due to these differences in concentration, the oxygen diffuses from the alveoli to the blood in the capillaries. At the same time, waste carbon dioxide diffuses from the blood into the alveoli. A higher concentration of carbon dioxide in the blood than in the air in the alveoli causes this gas to diffuse from the blood to the lungs. has been described as the process of getting oxygen from the air through the lungs and into the bloodstream, and carbon dioxide from the blood out of the body.

There are FOUR conditions required for gas exchange in animals

1. ______________________________ (air sacs and blood vessels) – so that gases can pass through the walls

2. ______________________________ – so that gases can dissolve and pass into the blood and cytoplasm of cells (which need materials in liquid, not gaseous form)

3. ______________________________ – so that gases can move by diffusion; there has to be a lower concentration of the gas in the place that the gas needs to move towards; movement of molecules occurs from higher towards lower concentrations

4. ______________________________ – so that the gases can be pushed in the direction that they need to move into; molecules will move from areas of higher towards areas of lower pressure

Internal Respiration

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As the oxygen laden blood passes through the body into the capillaries adjacent to the body cells, the reverse action takes place. This process is called internal respiration. Because of the chemical changes, _____ of food nutrients constantly going on within the cells, the cells' supply of oxygen is quickly while the by-product of food oxidation, carbon dioxide, .

This condition causes the oxygen to diffuse from the bloodstream into the cells, while the carbon dioxide leaves the cells and enters the bloodstream. Oxygen must constantly be replenished in the body cells, through the respiratory and circulatory systems, as it cannot be ____ by the body. Oxygen is absolutely essential in the cells, where it combines with food molecules, liberating the needed to maintain the body functions.

Relationship of Blood and Respiratory Systems

Neither external respiration nor internal respiration could take place without the ____ that flows in the circulatory system.

It is the blood that carries the oxygen to the cells of the body

It is the blood that accepts the carbon dioxide from the cells and delivers it to the lungs for exhalation.

Most of the oxygen diffusing into the bloodstream becomes bound to iron-containing ____ molecules within the red blood cells. Only a small fraction (less than 3 percent) of the total oxygen remains freely ___ in the plasma.

The combination of oxygen with haemoglobin allows for the transportation of sixty times as much oxygen as could be carried if the oxygen were solely in solution in the plasma. Each molecule of hemoglobin is capable of carrying molecules of oxygen. An average human red blood cell contains 280 million molecules of hemoglobin. Accordingly, a single erythrocyte, with fully saturated hemoglobin molecules, can transport about one billion oxygen molecules.

The chemical combination of hemoglobin and oxygen is loose and . Hemoglobin associates with oxygen in the capillaries of the lungs to form the bright red ____________ and dissociates from the union with oxygen in the capillaries of the body tissues to form the dark purplish ___________________________.

The amount of oxygen carried by hemoglobin depends upon the concentration of oxygen. At the normal concentration of oxygen in the arteries, 97% of the hemoglobin is combined with oxygen.

Carbon dioxide is carried in the bloodstream in several forms. About ______ remains in solution in the plasma. A further __ approximately, is attached to vacant carrier sites on hemoglobin molecules that have just emptied their oxygen into the tissues. It is then carried back to the lungs, and being loosely bound to the hemoglobin, it is freed to diffuse into the alveoli and is finally exhaled.

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About _______ of the carbon dioxide combines with the water in the plasma to form carbonic acid. This acid almost completely dissociates into bicarbonate ions (HCO3 -) and hydrogen ions (H+).

In the capillaries of the lung region, the process is reversed. As carbon dioxide diffuses into the respiratory channels, the amount of dissolved carbon dioxide in the plasma is reduce. The bicarbonate ions are reconverted into carbon dioxide molecules, which diffuse into the alveoli of the lungs.

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The Iron Lung

• If a person loses part or all of the ability to control the muscles involved in breathing, breathing becomes difficult or impossible.

• The person needing the iron lung is placed into the central chamber, a cylindrical steel drum.

• A door allowing the head and neck to remain free is then closed, forming a sealed, air-tight compartment

• Pumps that control airflow periodically decrease and increase the air pressure within the chamber, and particularly, on the chest.

• When the pressure is below that within the lungs, the lungs expand and atmospheric pressure pushes air from outside the chamber in via the person's nose and airways to keep the lungs filled.

• When the pressure goes above that within the lungs, the reverse occurs, and air is expelled.

• In this manner, the iron lung mimics the physiological action of breathing: by periodically altering intrathoracic pressure, it causes air to flow in and out of the lungs. The iron lung is a form of non invasive therapy.

• The iron lung now has a marginal place in modern respiratory therapy. Most patients with paralysis of the breathing muscles use modern mechanical ventilators that push air into the airway with positive pressure. These are generally efficacious and have the advantage of not restricting patients' movements or caregivers' ability to examine the patients as significantly as an iron lung does.

• However, negative pressure ventilation is a truer approximation of normal physiological breathing and results in more normal distribution of air in the lungs. It may also be preferable in certain rare conditions.

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Defense Mechanisms and Other Interesting Things

Coughing is a reflex action in response to irritation of the ___ , _ , or _____ membrane.

It can also be caused by nervousness, or it can be voluntary. There is a rapid _______ of the chest and diaphragm muscles causing a

sharp intake of air. The epiglottis closes as the chest and diaphragm muscles relax. This causes a buildup of __________ inside. The epiglottis suddenly opens and the air blows out carrying the irritating particles with

it. The main function is to protect the lungs from harmful particles that may be inhaled.

Sneezing is the sudden expulsion of air through the nose. Irritation of the lining of the _________ usually stimulates the sneezing

action. The air is taken in by normal breathing and then interrupted. The opening to the mouth is closed off by the soft palate and air is forced out through

the nose carrying the irritating particles with it. During a sneeze, the ______ stops momentarily.

Hiccoughing is the result of stimulating the ______ nerve. The impulse is carried to a center in the spinal cord which relays it to the diaphragm. It causes an involuntary contraction of all or part of the diaphragm forcing air out of the

lungs. The sudden closing of the epiglottis as air is drawn into the chest produces the sound. Hiccoughs can be caused by eating too fast, drinking too much alcohol, and by irritating

diseases of the digestive system, heart, and lungs.

Yawning is a combination of _______ and ________________ reactions resulting in an involuntary stretching of the mouth accompanied by a large intake of air.

The air is then exhaled as the mouth closes. It may be the result of a decrease in breathing rate due to tiredness, boredom, or drug

action. Since the body requires more oxygen there is a sudden of air in the form of a

yawn.

Snoring is the result of of the soft palate in the mouth while sleeping.

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Practice: Fill in the Blanks

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Respiratory Disorders

Disorder and Definition

Cause Symptom Treatment

Lung Cancer

Asthma

Emphysema

Bronchitis

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Disorder and Definition

Cause Symptom Treatment

COPD

Pneumonia

Cystic Fibrosis

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REWIEW – Respiration Practice Questions

Respiratory System Anatomy and Structure - Matching Question

____ 1. Tiny sacs where gases are exchanged

____ 2. Ridged bones in the nasal cavity that increase the warming, cleaning and moistening of incoming air

____ 3. Muscles that raise the ribs

____ 4. Tubes that branch off from the trachea

____ 5. The membrane that surrounds and touches the lungs

____ 6. The membrane that surrounds but does not touch the lungs

____ 7. The name of the cells that line the trachea and produce mucus

____ 8. The tube that connects the nasal and oral cavities with the trachea

____ 9. The sheet of muscle which separates the thoracic and abdominal cavities and is used in breathing

____10. The structure in which the vocal cords are found

____11. Tubes which connect the bronchi to the alveoli

____12. The name of the hairs that help to clean air as it is inhaled

____13. The condition that results from inflammation of the pleura

____14. The flap at the top of the trachea that opens during breathing and closes during swallowing

A. DiaphragmB. LungsC. TracheaD. BronchiolesE. TurbinatesF. RibsG. BronchiH. AlveoliI. Pharynx

J. IntercostalsK. Visceral pleuraL. Parietal pleuraM. Goblet cellsN. CiliaO. PleurisyP. EpiglottisQ. NostrilsR. Larynx

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Respiratory System Anatomy and Structure and Function – Multiple Choice Questions

1. Draw a picture of the trachea, bronchi, bronchioles, and lungs below. Label each part clearly.

2. What is at the end of every bronchiole?

3. Describe the path that oxygen takes as it enters the respiratory system. It should begin in your mouth and end at your muscles.

4. How do alveoli and capillaries help to get oxygen into your bloodstream and carbon dioxide out of your bloodstream?

5. People who have asthma sometimes have “asthma attacks”, which means their bronchioles swell up and close. Why could an asthma attack make it difficult to breathe?

6. Smoking cigarettes makes your alveoli less elastic (or “stretchy”), so they can’t expand as much. Explain why people who smoke often may have trouble breathing.

7. Explain one way that the respiratory system is important to the circulatory system. (What’s one reason your circulatory system wouldn’t work without your respiratory system?)

8. Breathing occurs in a predictable series of steps. First, air flows from the or through the (which is located at the back of the throat). Then, the air moves through the , a long pipe like structure, to the where the air is further moved to the location where gas transfer occurs, the , small air sacs located in the lungs.

9. What word best describes the function of the trachea? a) Pumping stationb) Entrance pointc) Muscled) Passageway

10. What is the "pipe" between the mouth and stomach called? a) epiglottisb) tracheac) esophagus

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11. The membrane on the surface of the lungs is called the? a) epidermisb) sagittalc) visceral pleurad) macromolecule

12. What are the increasingly smaller airways branching off into the lungs called? a) air sacsb) bronchial tubesc) capillariesd) lungs

13. What are the bubble-shaped sacs in the lungs where gas exchange takes place called? a) Capillariesb) bronchial tubesc) alveolid) lungs

14. When you inhale, the air pressure in the chest cavity... a) stays the same, allowing both pressures to be equalb) increases, allowing lungs to expandc) decreases, allowing outside air to flow into the lungsd) there is no air pressure in your chest cavity

15. Where does the transfer of oxygen into the bloodstream take place? a) In the heartb) In the tracheac) In the alveolid) In the nasal passages

16. The respiratory system exchanges gases between the ______ and the _______.a) Blood vessels, tissue fluids b) Air in lungs, bloodc) Air in lungs, air in organsd) Tissue fluid, blood

17. In the lungs, _____ gas enters the blood and _____ gas exits the blood. a) O2, PO4

b) CO2, H2O4

c) CO2, O2

d) O2, CO2

18. The term _______ means all the tubes that carry air into and out of the lungs.a) Airway passagesb) Aerobic vesselsc) Wind pipesd) Respiratory vasculature

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19. The cilia hairs and mucus of the conducting passagesa) filter impurities from the inspired air.b) reduce pulmonary pressure.c) reduce the surface tension in the alveoli.d) keep the lungs moist so gas diffusion can occur.

20. The conducting passages of the respiratory system do nota) warm the inspired air.b) exchange gases with the blood.c) clean the inspired air.

21. The list of conducting passages below is not in the correct sequence that an oxygen molecule would pass through as it was moving into the lungs. What is the correct sequence of the conducting passages?

1 = Trachea 2 = Pharynx3 = Nasal cavity4 = Bronchi5 = Larynx6 = Epiglottis

a) 1, 3, 5, 6, 4, 2 b) 6, 4, 3, 2, 5, 1c) 4, 1, 2, 3, 5, 6d) 3, 2, 6, 5, 1, 4

22. What is the correct order of structures an oxygen molecule would pass through before it entered the blood?

a) Bronchi, alveoli, bronchioles b) Trachea, alveoli, bronchiolesc) Bronchi, bronchioles, alveoli d) Pulmonary loop, alveoli, bronchi

23. Gas exchange between the air in the lungs and the blood occurs only in thea) Bronchi.b) Alveolic) Tracheary elementsd) Bronchioles

24. The diffusion of oxygen from the alveoli into the blood of the alveolar capillaries is rapid and

involves diffusion across how many layers of cells? a) 2b) 3c) 4d) 5

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25. The muscles used for normal inspiration are (more than one answer is possible)a) External intercostalsb) Bronchiolisc) Trachead majord) Diaphragm

26. Use of the inspiratory muscles causes expansion of the lungs, which produces _________ pressure inside the lungs.

a) increasedb) decreasedc) constantd) muscular

27. The fluid-filled membrane that surrounds the lungs is the _______.a) Pleurab) Peritoneumc) Synoviad) Pneuminear membrane

28. A chest wound can introduce air into the pleura space, leading to… a) Over oxygenation of the blood (due to air entering the lung through the hole)b) A collapsed lungc) Over oxygenation of the blood (due to air entering the blood in the wound)d) Lung filling with blood

29. The ability of the lung to return to its normal size after stretching is known asa) resilience.b) capacitance.c) elastic recoil

30. The vocal cords are in which part of the respiratory system? (Be as exact as possible). a) Larynx b) Pharynxc) Oral cavityd) Trachea

31. The amount of air that is inspired or expired in one breath during unforced breathing is the

a) residual volume.b) vital capacity.c) tidal volume.d) expiratory reserve volume.

32. The maximum amount of air that can be expired after a maximum inspiration is called the

a) residual volume.b) vital capacity.c) tidal volume.

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d) expiratory reserve volume33. During normal, relaxed respiration, about _____ ml of air enters and leaves the lungs

with each respiratory cycle.a) 500b) 1100c) 2300d) 4800

34. Oxygen is carried in the blood on _____ ions. a) Calciumb) Sodiumc) Irond) Bicarbonate

35. Bicarbonate ion (HCO3- ) and hydrogen ion (H+) are made when ______ reacts with

water.a) oxygenb) hydrogenc) carbon dioxided) carbon monoxide

36. Normal breathing rate is ______ breaths per minute a) 6 - 10b) 12 - 18c) 30 - 36d) 80 – 120

37. The rate and depth of respiration are set by control centers located in thea) pleurae.b) lungs.c) brain stem.d) diaphragm.

38. Which of the following is caused by destruction of the alveolar walls?a) asthma.b) emphysemac) chronic bronchitis.d) lung cancer

39. Which of the following is caused by conducting passages becoming swollen or blocked? (More than one answer is possible).

a) asthma.b) emphysemac) chronic bronchitis.d) lung cancer

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Respiratory System Anatomy and Structure and Function – Fill in the Blank Question

1) The main function of the respiratory organ system is _______ exchange between the ______ and the _______

2) The two major parts of the respiratory system are the _______, which are tubes that carry air, and the ______, which is where gases are exchanged with the blood.

3) In the lungs, the gas ______ enters the blood and the gas ______ exits the blood.

4) _____ means to breathe in, while _____ refers to breathing out.

5) The conducting passages not only conduct air to and from the lungs, they also _____ and ______ the before it reaches the lungs.

6) The conducting passages remove dust and other particles from the inspired air in this way: The particles become trapped on _______ in the conducting passages.

7) The mucus with the trapped dust particles is pushed upward, away from the lungs, by _____________.

8) What happens to the mucus that is pushed to the top of the respiratory tract? ______.

9) The _____ is the hollow structure at the top of the windpipe. It contains several cartilage structures and also the vocal cords.

10) The _____ is another term for the windpipe, a sturdy tube supported by rings of cartilage.

11) The correct anatomical term for the 'voice box' is the _____.

12) At the top of the larynx, the _____ acts as a flexible flap that prevents food from entering the larynx.

13) The structure on the neck commonly called the Adam's apple is the _____ of the larynx.

14*) In lab, you studied a model of the larynx like the one shownon the right. Name structuresA, B, and C on the model.

A = _____________B = _____________C = _____________

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15) The trachea, or windpipe, descends from the larynx into the _____ body cavity, where it ends by dividing into the two _____, which are the conducting passages that enter the lungs.16) Just posterior to the trachea is another tube passing through the thoracic cavity, the _____, a tube which carries food downward to the stomach.

17) Label the parts of the upper respiratory tract. Use the correct anatomical terms.

a)

b)

c) (a flap)

d)

18) Lungs have the property of _____which is the tendency to return to its initial size after being stretched (like a rubber band); This property assists in pushing air out of the lungs during expiration.

19) Bronchi in the lungs continuously branch until they form _____, the smallest conducting passages in the lungs.

20) Bubble-like structures called _____ (singular: _____) are the only lung structures in which gas exchange with the blood occurs. Air in the bronchi and bronchioles cannot exchange gases with the blood.

21) The walls of the alveoli are _________ tissue (be as specific as possible). This is a very thin tissue, so that gases can diffuse easily between the alveoli and the blood.

22) In the blank spaces after the respiratory system structures below, write a number (from 1 – 8) to show the order that you would encounter them if you were an inspired molecule of O2.

Bronchiole ______Epiglottis _____Pharynx ______Alveoli ______

Bronchi ______Trachea ______Larynx ______Capillary ______

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23) An unforced, or quiet, inspiration results primarily from the contraction of the _____ muscle and the _____ muscles, which expand the volume of the lungs.

24) Contraction of the diaphragm causes it to move _____, resulting in a(n) ______ in the size of the thoracic cavity and a(n) _____ in pressure within the lungs.

25) Contraction of the _____ elevates the ribs and sternum, resulting in an increase in the size of the thoracic cavity and a(n) _____ in pressure within the lungs.

26) Air enters the lungs during inspiration because the air pressure in the lungs is higher/lower (circle one) than the atmospheric air pressure outside the lungs.

27) Unless forced, expiration is caused by the _____ of the lung tissue. This occurs during relaxation of the _____ and _____ (muscles).

28) Many organs in the body (such as the heart, lungs, and digestive organs) are surrounded by a fluid-filled membrane. What is the term for any fluid filled membrane in the body? _______

29) Answer the following questions about the serosa that surrounds the lungs.

a) What is the name of the serosa that surrounds the lungs? _________________

b) The side of the lung serosa that attaches to the lungs is called its _______________ face.

c) The side of the lung serosa that attaches to the walls of the thoracic cavity is called its _______________ face.

30) The pleura allows the lungs to _____ inside the thoracic cavity during breathing.

31) The disorder ______ is painful breathing due to too little pleural fluid.

32) If air bubbles enter the pleural fluid (as might happen by a stab wound to the chest), the result is ________.

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Respiratory Unit Review

- Name 3 functions of the nasal passage

- Name all of the structures an air particle would pass or go through if it was breathed in (all the way to where external respiration takes place)

- What houses the vocal cords

- Name 3 ways of preventing “gunk” from clogging our airway

- What surface does gas exchange with the environment take place across?

- Explain the mechanics of breathing. Include 2 different muscles, volume changes, pressure changes, and direction of air flow

- Explain how CO2 concentration controls the breathing rate (explain homeostasis of blood pH)

- Differentiate between cellular respiration and gas exchange (either internal or external respiration)

- Explain tidal volume, inspiratory reserve, expiratory reserve, and vital capacity. Approx how much is tidal volume for the average person

- What does a spirometer measure?

- Describe (possibly with cause, symptoms and treatment) of the following disorders:o Lung Cancero Emphysemao Bronchitiso Asthmao Pneumoniao Cystic Fibrosis

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