Respiratory System

Chapter 37-3

Respiratory System Function:

Supply oxygen to body tissues Removes carbon dioxide, which is a waste

product, from the body tissues.

Purpose of Oxygen The cells use the oxygen to convert

carbohydrates and fats into energy. The byproduct for this process is

carbon dioxide, which the body exhales.

Cells need oxygen like cars need gas—for energy!

What makes up the respiratory system?

nose pharynx larynx trachea bronchi lungs diaphragm

LUNGS

At birth the lungs are pink, but as a person ages, they become gray and mottled from tiny particles breathed in with the air. (why?)

Generally, people who live in cities and industrial areas have darker lungs than those who live in the country

Pair of elastic, spongy organs used in breathing and respiration

Lungs In the adult human,

each lung is 25 to 30 cm (10 to 12 in) long

Their movements are controlled by the rib cage and the diaphragm

A hiccup is caused by a spasmodic, involuntary contraction of the diaphragm

Take a Breather!

An adult normally breathes from 14 to 20 times per minute, but vigorous exercise can raise the rate to 80 breaths per minute

A child’s rate of breathing at rest is faster than an adult’s at rest, and a newborn baby has a rate of about 40 breaths per minute. (Why?)

In general, smaller animals have faster breathing rates than larger animals. A rat, for example, breathes about 60 times per minute, while a horse breathes only about 12 times per minute.

Breathing Divided into two processes:

Inhalation - air is moved into the lungs

Exhalation - air is forced out of the lungs

Inhalation Diaphragm contracts

and flattens pulling air into the lungs.

Chest cavity expands to allow space for air.

Lungs expand when filled with air.

The amount of air normally taken into the lungs in a single breath during quiet breathing is called the tidal volume.

In adults the tidal volume is equal to about 0.5 liters

Generally about 4.8 liters (about 1.3 gal) – 6 liters in an adult male, but varies from one individual to the next.

Athletes can have a vital capacity of as much as 5.7 liters ( 1.5 gal) – 7 liters .

Inhalation:

Exhalation The diaphragm

relaxes by moving up to its original position

Air is pushed out.

Breathing A person can alter the rate of breathing and can

even stop breathing for a short time. But it is impossible to voluntarily stop breathing

permanently because breathing, like the heartbeat, is an involuntary activity controlled by nerve centers in the brain stem, the lower part of the brain.

These centers are connected with the muscles of the rib cage and diaphragm, and they increase or decrease the rate of breathing according to the needs of the body.

O2 diffuses through alveoli into capillaries

CO2 diffuses across in the opposite direction

The exchange of gases takes place when air reaches the alveoli.

Gas Exchange

BREAK!

Pathway1. Air first passes into the

nostrils 2. From there, the air passes

through the pharynx, which is shared with the digestive tract. (Why food doesn’t go to the lungs)

The Epiglottis is a flap of tissue that guards the entrance to the trachea, closing when anything is swallowed in order to prevent food or fluid from entering the lungs.

3) Air next passes through the larynx also called the voice

box, or vocal cords. The vocal cords are under tension, and a change in tension causes a change in pitch as air passes over them and they vibrate.

An inflammation of the larynx is called laryngitis.

Pathway

Pathway4) The larynx trachea, through

which the air passes next. The trachea has rings of cartilage, like

the rings in a vacuum cleaner hose, for support.

5) The trachea divides at its bottom end into two bronchi (sing. = bronchus), one to each lung. Mucus in the bronchi serves to trap

and coat dust particles so they don’t scratch or infect the delicate tissues in the lungs.

Lungs structure Anatomy The bronchi divide in the lungs

into smaller branches called bronchioles.

The tiniest bronchioles branch into the alveoli which are tiny, multi-lobed

air sacs must always stay moist Special cells in the alveoli

secretes moisture and keep them from sticking to each other when the person exhales.

alveoli The ability to secrete this chemical doesn’t

develop until around the eighth or ninth month of pregnancy, so there frequently is a problem in premature babies with the lack of surfactant causing the alveoli to stick together when the baby exhales.

Then, when the baby inhales again, the stuck alveolar cells tear away from their neighbors.

Scar tissue forms at these sites, thus the damage is permanent, and the person’s lungs lose some of their elasticity and ability to expand fully.

How to cure Hiccups ??? Hiccups

are spasms of the diaphragm thought to be caused by not enough CO2 in the

body. Thus, hiccups are frequently cured by

breathing into a paper bag.

Infections Bronchitis

is an inflammation of the bronchi, causing them to over-secrete mucus, which in turn, causes coughing to get it up.

Pneumonia and Tuberculosis Bacterial Infection of the lungs.

Asthma is an allergic reaction that causes constriction of the bronchioles,

thereby reducing the air passages, thus the amount of air that can get to the alveoli.

Emphysema is a progressive loss of elasticity in the lungs due to rupture of some

alveolar walls, coalescing of alveoli, and formation of scar tissue.

Lung Cancer Cigarette smoking is a major cause of lung damage. More than 4,000 substances found in cigarette smoke:

nicotine and carbon monoxide are the most common

Nicotine: Believed responsible for the addictive properties

of cigarettes, causes the release of epinephrine, a hormone secreted by the body.

This in turn produces an increase in blood pressure and heart rate.

Carbon monoxide: Prevents the blood from carrying the full amount

of oxygen, and over time this can be extremely harmful.

Lung Cancer Cigarette smoking damages: the lungs, bronchi, blood vessels, heart and other organs

and tissues. coughing, breathing problems, respiratory infections,

pneumonia, stroke, hardening of the arteries ( arteriosclerosis), stomach and intestinal ulcers, and cancer of the mouth, throat, esophagus, kidneys, bladder and pancreas.

Smoking during pregnancy increases the risk of miscarriage and fetal death. Even secondhand smoke has been reported to increase the risk of respiratory and middle ear infections in children and has been related to deaths due to lung cancer and heart disease.

Answer the Following…1) What happens to the diaphragm

during inhalation and exhalation?2) Describe the pathway air will travel

through the respiratory system.3) How does the circulatory and

respiratory system work together to make sure your body gets oxygen and gets rid of carbon dioxide?