Ch. 34

From which structures do oxygen molecules move from the lungs to the blood?

Alveoli

The respiratory center of the brain is most sensitive to levels of __________ in the blood.

CO2

Why are respiratory surfaces, such as living cell membranes, moist?

Gases must dissolve in water to cross cell membranes

A person with emphysema usually has less energy and less strength than a healthy person. Why?

He or she is not getting enough oxygen to all of the cells in the body

What drives the movement of gases at the tissue level?

In body cells, carbon dioxide concentration is high and oxygen concentration is low.

Emphysema can lead to larger, pouch-like alveoli. Why is this a problem?

Larger, pouch-like alveoli translate to less total surface area for transporting oxygen into the bloodstream.

How is a gradient maintained so that carbon dioxide will diffuse from body cells into the plasma?

Most carbon dioxide enters red blood cells where it immediately combines with water to produce bicarbonate ions and hydrogen ions.

What is the function of the epiglottis in the respiratory system of humans?

The epiglottis prevents food from entering the larynx.

By picking up hydrogen ions, hemoglobin prevents the blood from becoming too _____.

acidic

Gas exchange occurs in tiny air sacs in the lungs called __________

alveoli

In the lungs, carbon dioxide leaves red blood cells and enters the __________

alveoli

Most carbon dioxide is carried from the body tissues to the lungs _____.

as bicarbonate ions (HCO3 -)

The trachea splits into two large branches called ____________ , which then divide repeatedly into even smaller tubes called ___________.

bronchi, bronchioles

Respiration provides the body with oxygen and also eliminates __________, one of the waste products of cellular respiration.

carbon dioxide

In the blood most of the oxygen that will be used in cellular respiration is carried from the lungs to the body tissues _____.

combined with hemoglobin

Fish exchange gases with the water by __________ exchange, which involves water and blood flowing over the gills in opposite directions.

countercurrent

What respiratory adaptation allows fish to maximize oxygen transfer from water to the blood?

countercurrent exchange

Although amphibians use gills during their aquatic larval stage and develop simple, saclike lungs as adults, some may also depend on an additional mechanism for gas exchange. What is it?

diffusion of gases into and out of capillaries through their thin, moist skin

John, a smoker, sees his doctor because he is experiencing shortness of breath even while at rest. His doctor orders a high-resolution CT (HRCT) of John's chest. Upon examination of the scan, the doctor noted an increase in size of the airspaces in John's lungs. What diagnosis will the doctor make?

emphysema

In the throat, the opening to the larynx is guarded by the ____________ , a flap of tissue that prevents food from entering the airways.

epiglottis

Nearly all of the oxygen carried by blood is bound to ____________, an iron-containing protein that gives red blood cells their color.

hemoglobin

During the ___________ stage of breathing, the chest cavity expands and air rushes into the lungs. During __________ , the chest cavity decreases in size and air moves out.

inhalation, exhalation

Hemoglobin,

is a protein that can bind four molecules of oxygen.

After blood becomes oxygenated,

it returns to the heart, and is then pumped to body cells.

Voice sounds are produced by the _____.

larynx

Where is the respiratory center located?

medulla

What is the key feature that characterizes emphysema?

much less surface area in the lungs

The primary functions of the _____ are to warm, filter, and humidify air.

nasal cavity

Aquatic animals that lack a circulatory system for transporting gases __________.

often have flattened bodies

Which of the following is common to both bird and mammal lungs?

oxygen and carbon dioxide diffusion into/out of capillary blood

Which of the following represents the correct path of air during the process of inhalation?

pharynx, larynx, trachea, bronchi, bronchioles, alveoli

You observe an earthworm crawl across the pavement on a warm, sunny day and notice that its skin is drying out. What will be the immediate result of dry skin and the ultimate cause of death?

suffocation

During inhalation,

the diaphragm and rib muscles contract.

Which of the following structures is the site of gas exchange in insects?

tracheoles