Gas Exchange

How does air move in and out of your lungs? 1. What specific structure within the lungs assist with this process? 2. How do surfactants assist in this process? 3. What does pressure in your environment have to do with it?

1. 2. Surfactants keep alveoli surfaces moist and from sticking shut 3.

Gills are unsuitable for animals living on land because A) the large surface area of gills would allow dehydration of the animal. B) air cannot diffuse across the gill surface. C) there is no way to get air into the gills. D) gills require high blood pressure. E) gills do not function well in animals that have a diaphragm.

A

In the capillaries of the body, oxygen released from hemoglobin first diffuses into the A) blood plasma. B) pulmonary veins. C) pulmonary arteries. D) interstitial fluid. E) alveoli.

A

Medullary breathing centers directly sense and respond to A) blood pH and CO2 concentration. B) blood O2 concentration. C) alveolar CO2 concentration. D) alveolar O2 concentration. E) blood pH and O2 concentration.

A

The organization of blood and water flow in a fishʹs gills increases the fishʹs ability to A) extract oxygen from the water. B) extract carbon dioxide from the water. C) detect toxic materials in the water. D) transport blood throughout the fishʹs body. E) regulate fluid excretion from the body.

A

List the two advantages that terrestrial organisms have over aquatic organisms when it comes to respiration.

Air has a higher concentration of oxygen, and air is much lighter than water

Animals that effectively use their body surface for gas exchange must A) be terrestrial. B) have a high ratio of body surface area to volume. C) have a low ratio of body surface area to volume. D) be aquatic and nearly spherical. E) have a special kind of hemoglobin.

B

Cigarette smoke can affect macrophages that reside in our lungs for the purpose of A) preventing emphysema. B) engulfing particles and microorganisms. C) enhancing oxygen and carbon dioxide exchange. D) producing antibodies. E) maintaining the appropriate pH and moisture content within the lungs.

B

Evolutionary adaptations for survival on land produced tetrapods, which later evolved into A) snakes and skinks. B) amphibians, reptiles, and mammals. C) frogs and toads. D) migratory birds. E) humans.

B

When people think of breathing, they typically tend to think of inhalation. Briefly explain why this is inaccurate.

Breathing includes both inhalation and exhalation

Gas exchange involves three stages. List and briefly describe the three stages.

Breathing—inhalation of oxygen and exhalation of carbon dioxide. Transport of gases—oxygen and carbon dioxide must be transported to and from the tissues of the body. Gas exchange with tissues of the body—oxygen and carbon dioxide must be exchanged at the cellular level.

In most animals, gas exchange occurs in three phases. What are they?

Breathing—inhalation of oxygen and exhalation of carbon dioxide. Transport of gases—oxygen and carbon dioxide must be transported to and from the tissues of the body. Gas exchange with tissues of the body—oxygen and carbon dioxide must be exchanged at the cellular level.

An oxygen molecule enters an alveolus. If it is to reach a red blood cell, its next step must be to A) pass down a bronchiole to an air sac. B) diffuse across the alveolar epithelium. C) dissolve in the fluid lining the alveolus. D) dissolve in the plasma of blood surrounding the alveolus. E) diffuse across a capillary epithelium.

C

Compared to the vital capacity, how much air can lungs actually hold? A) always less B) sometimes less C) always more D) sometimes more E) always the same amount

C

A common misconception is that your body regulates breathing in response to the levels of O2. What actually regulates respiration rate?

CO2

List the steps involved in an infant taking its first breath upon birth

CO2 levels rise in the fetus once it is born. The pH drops and stimulates the breathing control center in the brain to trigger breathing

Where does the actual exchange of gases occur in cells? In your lungs?

Cells - Mitochondria (cellular respiration) Lungs-Alveoli

The transfer of oxygen between two fluids that are moving in opposite directions is referred to as

Countercurrent Exchange

The ____________ is a muscular partition that separates the ____________ cavity from the ____________ cavity

Diaphram Thoracic Abdominal

If you were to move from around sea level to a much higher altitude, your body would respond with A) profuse sweating. B) a decrease in the diameter and number of capillaries close to your bodyʹs surface. C) an increase in energy production. D) a decrease in the affinity of hemoglobin for oxygen. E) an increase in the number of your red blood cells.

E

In the final phase of respiration, body cells A) release CO2 to red blood cells. B) take up O2 from red blood cells. C) increase in size to accommodate the reuptake of O2. D) migrate to the circulatory system. E) release CO2 and take up O2.

E

Inhalation in humans is achieved by A) contraction of muscles in the lungs. B) contraction of the diaphragm. C) relaxation of the diaphragm and chest muscles. D) relaxation of the diaphragm. E) contraction of the diaphragm and chest muscles.

E

Most CO2 is transported to the lungs A) dissolved in the plasma. B) attached to hemoglobin. C) as carbonic anhydrase. D) as carboxyl. E) as bicarbonate ions.

E

The reason animals need a continuous supply of oxygen is to A) make carbon dioxide. B) synthesize protein. C) dispose of carbon dioxide. D) carry out glycolysis. E) obtain energy from their food.

E

When you exhale, you A) release oxygen and carbon dioxide. B) exchange CO2 for O2. C) take up oxygen and release carbon dioxide to the blood. D) take up carbon dioxide and release oxygen. E) remove CO2 from the body.

E

Which of the following contributes to gas exchange in the human fetus? A) lower blood pH of the embryo B) lack of turbulence in the fetal blood C) lower pressure of the gases O2 and CO2 D) high oxygen levels maintained in the amniotic fluid by the placenta E) the increased oxygen binding capability of fetal hemoglobin

E

True or false: The countercurrent creates an oxygen gradient only at the point where the capil-laries merge into larger blood vessels. If false, make it a correct statement.

False, countercurrent flow creates an oxygen gradient along the entire capillary

True or false: Oxygen-depleted blood traveling from your leg muscles travels directly to the lungs to get oxygenated without going through the heart. If false, make it a correct statement.

False, the blood from your leg muscles would first travel to your heart and then to your lungs.

True or false: Gas exchange occurs via osmosis. If false, make it a correct statement....

False; Gas exchange occurs through DIFFUSION

A teacher is grading short-answer questions from an anatomy and physiology quiz. The short-answer question she is grading asked the students to describe the role of hemoglobin in humans. A student answers as follows: "Hemoglobin carries oxygen throughout the body to cells that require it." If the teacher is correcting incorrect answers by giving written feedback, what would she write to this student?

Hemoglobin also carries CO2 away from tissues and helps to buffer pH in the blood.

The total pressure of a mixture of gas is a combination of all the pressures of the different gases in the mixture. In other words, each gas in the mixture has a(n)

Partial Pressure

The passageway for both air and food: ____________

Pharnyx

What to major organ systems are involve in gas exchange?

Respiratroy system (nasal cavity, lungs, etc.) and Circulatory system (Heart, lungs, blood vessels, capillaries)

What does the breathing control center do? Be specific.

The part of the brain called the medulla oblongata forms a pair of control centers that controll the breathing rhythm. Nerves from the medulla signal the diaphram to contract causing you to inhale. Between inhalations the muscles relax whn you exhaele The control center used info about changes in your internal body to coordinate your breathingrate for your body's need for O2. Sensors in the medulla also monitor PH in the cerebrospinal fluid as an indicator of CO2 in the blood. So if you excercise your medulla will sense changes an increase your breathing

The part of an animal's body where gas exchange occurs is known as

The respiratory surface

Why is it important for respiratory surfaces to be moist & thin?

Thin/moist layer allows O2 to diffuserapidly into the circulatory system or into the body tissues; it also helps CO2 diffuse out This thin and moist helps diffusion

A person has a mutation in a gene that leads to a decrease in the efficiency at which O2 is picked up by the blood. Would this person have difficulty doing certain activities? If so, which ones? Briefly explain your answer

This person would have difficulty doing even mild exercise or strenuous activities because his or her ability to carry oxygen would be hindered

In the tracheal system, the circulatory system is bypassed by small branches, called ____________, that contact most of the insect's cells

Tracheoles

True or false: The placenta contains both fetal and maternal tissues. If false, make it a correct statement

True

The maximum amount of air you breathe in and out is known as your _________.

Vital Capacity

Structures that air passes across to produce sound: ____________

Vocal Cords

Curare is a generic term for a toxin prepared from numerous plant species native to South America. Curare interferes with the brain's communication with skeletal muscle cells. In effect, curare stops skeletal muscles from contracting. Would this drug affect human breathing? If so, what would its effect be?

Yes, because breathing is aided by contraction of skeletal muscles. It would have a negative effect on breathing.

Site of gas exchange within the lungs: ____________

alveoli

Air passes into these from the trachea: ____________

bronchi

Inflammation in these tubes is called bronchitis: ____________

bronchioles

Blood that is leaving the lungs is high in _______and low in _________.

o2 Co2

Substances that keep the alveoli from collapsing and sticking shut: ____________

surfactants

Why do we breathe?

to exchange gases (O2 & CO2)

How does tidal volume & vital capacity differ?

vital capacity is the maximum volume of air that can be inhaled and exhaled with each breath (between 3.4 L to 4.8 L)

What is meant by dead air?

when you exhale your alveoli do not fully collapse - some dead air remains in alveoli no matter how hard you blow out

Labored breathing, coughing, lung infection, and respiratory failure are characteristics defining A) tuberculosis. B) meningitis. C) chronic obstructive pulmonary disease. D) multiple sclerosis. E) myasthenia gravis

C

Oxygen is mostly transported through the body A) dissolved in the blood. B) dissolved in red blood cells. C) bound to hemoglobin. D) bound to dissolved iron. E) bound to carbon.

C

The ________ is a passageway shared by both food and air. A) alveolus B) trachea C) pharynx D) larynx

C

The chief advantage of gas exchange in water is that A) water can contain more oxygen than air. B) carbon dioxide is easier to eliminate in water than in air. C) no energy is used to keep the exchange surface wet. D) less energy is required to ventilate gills as compared to lungs. E) contact between the respiratory surface and the gas-containing medium is more efficient in water than in air.

C

The tracheal system of an insect is most like which of the following? A) the exhaust system of an automobile B) the electrical wiring in a home C) the air duct system in a building D) a river system draining a large region E) leaves on a tree

C

Which of the following options correctly lists the direction of carbon dioxide travel as it leaves the body? A) alveoli, bronchioles, bronchi, trachea, pharynx, larynx B) alveoli, bronchi, bronchioles, trachea, larynx, pharynx C) alveoli, bronchioles, bronchi, trachea, larynx, pharynx D) alveoli, bronchi, bronchioles, trachea, pharynx, larynx E) alveoli, trachea, bronchioles, bronchi, pharynx, larynx

C

Which of the following statements is false? A) Most amphibians use lungs and skin for gas exchange. B) Unlike the tracheal system of insects, vertebrate lungs are restricted to one location in the body. C) Vocal cords in our bronchi allow us to speak. D) It is easier to use the O2 in air than in water because air is easier to move. E) Gas exchange in the human lungs occurs in the alveoli.

C

State the four specialize body parts through which gas exchange can occur. 1. Briefly describe how they work. 2. What environment they are used in (e.g. terrestrial vs. aquatic)?

1. The outer skin - O2 diffuses into a dense network of thin walled capillaries lying just beneath the skin (earthworms) 2. Tracheal system - terrestrial - air tubes extend through the body and exchange gases with body cells (insects) 3. gills - aquatic - extensions or outfoldings of the body surface specialized for gase exchange - gasses diffuse across the gills surface between water and blood 4 - Lungs - terrestrial - gases are carried from the lungs by the circulatory system to the body cells

Oxygen moves from blood into the interstitial fluid and then to body cells because A) it diffuses from a region of higher partial pressure to a region of lower partial pressure. B) it diffuses from a region of lower partial pressure to a region of higher partial pressure. C) it descends down an osmotic gradient, following the movement of water. D) the cells of the body create molecular attractions that pull the oxygen to them. E) oxygen diffuses from a higher to a lower pH.

A

What prompts a newborn baby to start to breathe? A) an increase in the concentration of carbon dioxide in the babyʹs blood B) a decrease in the concentration of oxygen in the babyʹs blood C) a change in the temperature on the surface of the skin D) exposure to air E) an increase in the pH of the babyʹs blood

A

Which of the following is likely to have the lowest concentration of O2? A) warm salt water B) cool salt water C) warm fresh water D) cool fresh water E) air

A

Which of the following organisms has a respiratory system that does not require a circulatory system? A) grasshopper B) mouse C) earthworm D) carp E) crayfish

A

Which of the following statements about fish gills is true? A) They have a surface area that is much greater than the body surface. B) They aid in reproduction. C) Because of their efficiency, they only need a small surface area. D) They have a poor blood supply. E) Like lungs, they have an exhale/inhale function.

A

Within the lungs, gas exchange occurs across A) alveoli. B) tracheae. C) bronchioles. D) diaphragms. E) bronchi.

A

If you could alter the shape of a frog so that it was long and thin instead of compact, the frogʹs oxygen transfer efficiency would A) increase, because the frog would be larger. B) decrease, because thereʹs more skin area to keep moist. C) increase, because the frog would have more surface area in relation to body volume. D) decrease, because a long body has more contact with the soil or water. E) not change at all, because the body volume would remain constant.

C

Cigarette smoking and secondhand smoke cause cancer due to the A) effects they have on our breathing mechanisms. B) toxins in the smoke. C) resistance they have for products of our immune system. D) immunosuppressive effects they display. E) lack of antioxidants in smoke.

B

In a mammal, blood leaving the lungs goes to A) the kidneys. B) the heart. C) the limbs. D) the liver. E) the brain.

B

In the countercurrent exchange system of fish gills, A) blood and water flow in the same direction. B) blood and water flow in opposite directions. C) blood and water are separated by a thick polysaccharide barrier. D) blood flow in the gills reverses direction with every heartbeat. E) water flow over the gills reverses direction with every inhalation.

B

The body structure where gas exchange occurs is called the A) integumentary surface. B) respiratory surface. C) capillary surface. D) exchange network. E) capillary network.

B

The maximum amount of air that a human can inhale and exhale is called the A) tidal volume. B) vital capacity. C) maximum capacity. D) physiological volume. E) inhalation capacity.

B

The oxygen-carrying component in red blood cells is A) carbon dioxide. B) hemoglobin. C) bicarbonate ions. D) iron. E) the cell membrane.

B

When you hold your breath, which of the following blood gas changes leads initially to the urge to breathe again? A) rising oxygen concentration B) rising carbon dioxide concentration C) falling oxygen concentration D) falling carbon dioxide concentration E) falling nitrogen concentration

B

Which of the following is a function of the nasal cavities in humans? A) secreting enzymes for digestion B) warming inhaled air C) secreting excess carbon dioxide into exhaled air D) determining O2 content in inhaled air E) providing a tract for nerve distribution

B

Why do cigarette smokers cough more than nonsmokers? A) The tar in cigarette smoke tends to make alveoli stick together, and coughing separates them. B) Cigarette smoke harms the cilia that normally move debris out of the lungs, and coughing is the remaining way to clean the lungs. C) Cigarette smoking partially paralyzes the muscles in the lungs, resulting in an increased residual volume, and coughing exchanges this ʺdead air.ʺ D) Coughing stimulates blood flow to the lungs. E) By raising the pressure in the lungs, coughing forces more oxygen into the blood.

B

A waste product of respiration is A) water. B) electrons. C) hydrogen peroxide. D) carbon dioxide. E) glucose.

D

Air leaving human lungs during exhalation contains A) no oxygen. B) no carbon dioxide. C) mostly carbon dioxide and carbon monoxide. D) carbon dioxide and unused oxygen. E) one-half oxygen and one-half carbon dioxide.

D

Evolutionary movement of aquatic animals to land involved an intermediate individual that A) could fly. B) is called a ʺpodafish.ʺ C) evolved a tracheal system of branching internal tubes. D) had both gills and lungs. E) had ribs to protect the heart and lungs.

D

The function of passageways for gas exchange in birds is to A) lighten the bird. B) adjust the temperature of air. C) clean the air. D) permit one-way ventilation of the lungs. E) store air for times of physical exertion.

D

What name is given to the sheet of muscle that helps move air in and out of the lungs? A) trachea B) alveolus C) larynx D) diaphragm E) bronchus

D

What part of the human brain contains the primary breathing control center? A) neocortex B) hippocampus C) cerebellum D) medulla oblongata E) thalamus

D

When you are breathing normally, exhalation results mainly from A) the contraction of muscles in the chest. B) the contraction of the diaphragm. C) the contraction of muscles in the lungs. D) the relaxation of the chest muscles and diaphragm. E) low pressure in the lungs.

D

Which of the following animals requires the largest and most complex lungs proportional to its overall body size? A) frog B) snake C) turtle D) bear E) newt

D

Which of the following statements regarding breathing and circulation is false? A) Insects lose very little water by using a tracheal system to breathe. B) Air-breathing animals lose water by evaporation. C) The tracheal system of insects consists of a series of branching air tubes that extend from the surface to deep inside the body. D) A terrestrial animal spends much more energy than an aquatic animal ventilating its respiratory surface. E) The circulatory system of insects is not involved in transporting oxygen.

D

Briefly explain how the volume in your thoracic cavity changes during inhalation and exhala-tion. Be sure your answer includes how those changes in volume lead to air moving in and out.

During inhalation, the volume of air increases, which causes the pressure to drop and air to rush in from outside. During exhalation, the volume of air decreases, which causes the pres-sure to increase and air rush to out.

Explain the difference between inhalation and exhalation. Think about what changes occur in the thoracic cavity.

Inhalation: o Ribs move upwards and out as muscles between the ribs contract o Diaphragm contracts and moves down o These contractions expand the volume of thoracic cavity • Lungs have natural elasticity, expands with thoracic cavity o Air pressure in the alveoli decreases • Become lower than atmospheric pressure • Air moving from high to low pressure, is pulled from the surrounding atmosphere through nostrils and lungs Exhalation: o Rib muscles and diaphragm relax o Volume of thoracic cavity reduces o Lungs return to relaxed and unstretched position o Increases in alveolar air pressure forces air up the breathing tubes and out of the body • Vital capacity: volume of air breathed during maximal inhalation and exhalation • Lungs actually hold more air than the vital capticity o Alveoli do not completely collapse • A residual volume of dead air remains in lungs

What is the correlation between metabolic activity and the surface area of the gas exchange surface in an organism....

The higher the metabolic activity, the greater the surface area of the gas exchange surface

A person has a mutation that causes his cilia to form or function incorrectly. What would this person have difficulty doing?

This person would have difficulty sweeping mucus out of his or her lungs

What are the major components of the respiratory system?

• Lungs are located in your chest (thoracic cavity)Are protected by supportive rib cage • Diaphragm: a sheet of muscles that separates the thoracic cavity from the abdominal cavity • Nostrils - Air enters respiratory system through these and is filtered by hairs and warmed, humidified, and sampled for odors o Mouth • Pharynx - After air passes through the mouth or nose, it passes through the pharynx (where both air and food goes) Note - When you swallow food, the larynx (upper part of respiratory tract) moves upward and tips the epiglottis over the opening of your trachea (windpipe) • Larynx aka voice box • As you exhale the outgoing air rushes by a pair of vocal cords in the larynx • Trachea - From the larynx are passes through the trachea o Rings of cartilage reinforce the walls of the larynx and trachea • Trachea forks into two bronchi - One leading to each lung • Bronchus braches form into finer and finer tubes called bronchioles • Alveoli - Bronchioles dead-end in grapelike clusters of air sacs called alveoli • Inner surface of each alveolus is lined with a thin layer of epithelial cells