Section 1
Lungs Exchange Gases to Support Life
When you breathe, oxygen enters the lungs and passes through thin-walled air sacs called alveoli into your bloodstream, while carbon dioxide waste moves from blood into lungs for removal.
In this Grade 7 Life Science lesson from Chapter 18, students learn about the structures and functions of the respiratory system, including how it exchanges oxygen and carbon dioxide to meet the body's needs. The lesson introduces key concepts such as cellular respiration and how mechanical movements and chemical reactions work together to transport air into the lungs and deliver oxygen to cells. Students also explore how the body maintains homeostasis by regulating oxygen and carbon dioxide levels through the respiratory system.
Section 1
Lungs Exchange Gases to Support Life
When you breathe, oxygen enters the lungs and passes through thin-walled air sacs called alveoli into your bloodstream, while carbon dioxide waste moves from blood into lungs for removal.
Section 2
Cells Transform Oxygen and Glucose Into Energy
During cellular respiration, your cells combine oxygen from breathing with glucose from food to release energy. This process produces carbon dioxide waste that must be removed from the body.
Section 3
Muscles Move Ribs and Diaphragm During Breathing
When you inhale, your diaphragm contracts downward and rib muscles pull outward, expanding the thoracic cavity. This creates space for lungs to fill with air; relaxation reverses this process for exhalation.
Section 4
Air Vibrates Vocal Cords to Produce Speech
Your respiratory system enables speech when air from lungs passes through vocal cords in the larynx, causing them to vibrate. Muscles in your throat, mouth, and lips shape these vibrations into words.
Section 5
Nose Filters Air to Protect Lungs
When you inhale through your nose, tiny hairs called cilia and sticky mucus trap dust, pollen, and other harmful particles. This filtration system prevents dangerous materials from reaching your lungs.
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Section 1
Lungs Exchange Gases to Support Life
When you breathe, oxygen enters the lungs and passes through thin-walled air sacs called alveoli into your bloodstream, while carbon dioxide waste moves from blood into lungs for removal.
Section 2
Cells Transform Oxygen and Glucose Into Energy
During cellular respiration, your cells combine oxygen from breathing with glucose from food to release energy. This process produces carbon dioxide waste that must be removed from the body.
Section 3
Muscles Move Ribs and Diaphragm During Breathing
When you inhale, your diaphragm contracts downward and rib muscles pull outward, expanding the thoracic cavity. This creates space for lungs to fill with air; relaxation reverses this process for exhalation.
Section 4
Air Vibrates Vocal Cords to Produce Speech
Your respiratory system enables speech when air from lungs passes through vocal cords in the larynx, causing them to vibrate. Muscles in your throat, mouth, and lips shape these vibrations into words.
Section 5
Nose Filters Air to Protect Lungs
When you inhale through your nose, tiny hairs called cilia and sticky mucus trap dust, pollen, and other harmful particles. This filtration system prevents dangerous materials from reaching your lungs.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter