Respiration and Excretion The Respiratory System Smoking and Your Health The Excretory System Table of Contents

Respiration and Excretion

The Respiratory System

Smoking and Your Health

The Excretory System

Table of Contents


The Air You Breathe

The air you breathe in contains several different gases, shown in the circle graph on the left. The air you breathe out contains the same gases, but in the amounts shown in the circle graph on the right.

- The Respiratory System


The Air You Breathe

Percent of a gas breathed in or out

Reading Graphs:

What does each wedge of the graphs represent?



The Air You Breathe

Oxygen; less oxygen is breathed out than breathed in—meaning that some must have been used by the body.

Interpreting Data:

Based on the data, which gas is used by the body? Explain.



The Air You Breathe

There is a higher percentage of carbon dioxide in exhaled air. Carbon dioxide is a waste product of cellular activity.

Drawing Conclusions:

Compare the percentage of carbon dioxide in inhaled air with the percentage in exhaled air. How can you account for the difference?



The Air You Breathe

Nitrogen is not used by the body and is not a waste product.

Inferring:

Explain why the percentage of nitrogen is the same in both inhaled air and exhaled air.


Respiration and Excretion - The Respiratory System

Respiratory System Functions

Oxygen from the air and glucose from digested food are both carried to the cells by the blood. During respiration, oxygen reacts with glucose to release energy.


The Path of Air

As air travels from the outside environment to the lungs, it passes through the following structures: nose, pharynx, trachea, and bronchi.


Gas ExchangeAfter air enters an alveolus, oxygen passes through the wall of the alveolus and then through the capillary wall into the blood. Carbon dioxide and water pass from the blood into the alveoli.


Surface Area Surface area refers to the total area of all the surfaces of a three-dimensional object. Consider a cube, which has six equal sides. Each side measures 2 cm by 2 cm.

1. To find the surface area of the cube, first calculate the area of one of the six sides:

Area = length X width = 2 cm X 2 cm = 4 cm2

Each side has an area of 4 cm2.

2. Then, add the areas of the six sides together:

4 cm2 + 4 cm2 + 4 cm2 + 4 cm2 + 4 cm2 + 4 cm2 =

24 cm2

The surface area of the cube is 24 cm2.



Surface Area

Practice Problem

Calculate the surface area of a cube whose sidemeasures 3 cm.

54 cm2



How You Breathe

When you breathe, the actions of your rib muscles and diaphragm expand or contract your chest. As a result, air flows in or out.


Breathing Process Activity

Click the Active Art button to open a browser window and access Active Art about the breathing process.



Breathing and Speaking

Two vocal cords, folds of connective tissue that produce your voice, stretch across the opening of the larynx. Air moving over the vocal cords causes them to vibrate and produce sound.


SequencingAs you read, make a flowchart that shows the path of air in the respiratory system. Write each step of the process in a separate box in the order in which it occurs.

Path of AirAir enters the nose.

To the pharynx

To the trachea

To the bronchi

To the lungs

To the alveoli



End of Section:The Respiratory

System

Respiration and Excretion - Smoking and Your Health

Chemicals in Tobacco Smoke

Some of the most deadly chemicals in tobacco smoke are tar, carbon monoxide, and nicotine.

Respiration and Excretion - Smoking and Your Health

Health Problems and Smoking

Over time, smokers can develop chronic bronchitis, emphysema, lung cancer, and atherosclerosis.


Relating Cause and EffectAs you read, identify the effects of smoking on the body. Write the information in a graphic organizer like the one below.

Smoking

Increase in breathing and heart rate due to carbon monoxide in smoke

Damage to protective cilia and risk of cancer due to tar

Addiction and increase in blood pressure due to nicotine

Risk over time of chronic bronchitis, emphysema, lung cancer, and atherosclerosis

- Smoking and Your Health

Cause

Effects


Links on Respiratory Disorders

Click the SciLinks button for links on respiratory disorders.

- Smoking and Your Health


End of Section:Smoking and Your Health

Respiration and Excretion - The Excretory System

Filtration of Wastes

Each kidney contains about a million tiny filtering units called nephrons.


Previewing VisualsBefore you read, preview Figure 11. Then write three questions you have about the diagram in a graphic organizer like the one below. As you read, answer your questions.

Q. Where are nephrons located?

A. In the kidneys

Q. What three main materials are filtered out of the blood?

A. Urea, water, glucose

How the Kidneys Filter Wastes

Q. What happens to these filtered materials?

A. Most of the water and glucose are reabsorbed. Most of the urea remains as urine.

- The Excretory System


Links on Organs of Excretion

Click the SciLinks button for links on organs of excretion.



Sweat

Click the Video button to watch a movie about sweat.



End of Section:The Excretory

System


Graphic Organizer

Blood flows into the nephron’s capillary cluster.

Water, urea, glucose, and other materials are removed from the blood and flow into the capsule.

From the capsule, the substances flow intoa long tube.

In the tube, glucose, water, and some other materials are reabsorbed.

Urine flows from the kidneys through the ureters to the urinary bladder.


End of Section:Graphic Organizer

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Respiration and Excretion The Respiratory System Smoking and Your Health The Excretory System Table of Contents