Respiratory SystemRespiratory System

Structures and Functions

Parts of Respiratory SystemParts of Respiratory System

Nasal Cavity Pharynx Larynx Trachea Bronchi Bronchioles Alveoli

Lungs Pleura

Functions of the Respiratory Functions of the Respiratory SystemSystem

Provides oxygen for the body and removes carbon dioxoide through respiration

Production of sound

Respiratory SystemRespiratory System

Body has an average oxygen reserve to last about 4 –6 minutes

If reserve is not replenished , death is the outcome

Respiratory TractRespiratory Tract

Upper Respiratory Tract– Nose– Pharynx– Larynx

Lower Respiratory Tract– Trachea– All segments of the

bronchial tree– Lung

Nasal CavityNasal Cavity

Air enters body through nostrils (anterior nares)

Inside the nostrils, are 2 spaces known as nasal cavities

Nasal cavities are lined with mucous membranes

Nasal CavityNasal CavityNasal Septum—divides

nasal cavities into right and left sides

Three turbinates or bones that protrude into the nasal cavity—they increase surface area for filtering dust and dirt

Cilia—the hairs in your nose that trap larger dirt particles

Changes To The Air As It Comes InContact With the Lining of the Nose

Foreign bodies filtered out by cilia and mucous membrane

Air is warmedAir is moistened

Effect of Smoking on CiliaEffect of Smoking on Cilia Cigarette smoke paralyzes

the cilia and results in accumulations of mucus and the typical smoker’s cough, which is an effort to clear the secretions

Sense of SmellSense of SmellOriginates in your

nose!Olfactory nerves

(which provide the sense of smell) are located in the mucus membrane.

SinusesSinuses Cavities in skullDucts connect sinuses to

nasal cavityNamed: frontal,

maxillary, sphenoid, and ethmoid

Give resonance to voice (nasal sound when you have a cold due to blockage or sinuses)

PharynxPharynxThe throatCommon

passageway for air and food

5 inches long

PharynxPharynx When food is swallowed,

the EPIGLOTTIS closes over the opening to the larynx, preventing food from entering the lungs

Eustachian tube connect the middle ear to the nasopharynx

LarynxLarynx

The voice box Triangular chamber below

pharynx Within the larynx are vocal

cords (GLOTTIS) It is composed of several

pieces of cartilages – the largest is the Adams’s Apple

TracheaTrachea

Windpipe 41/2 inches long Walls are bands of C-

shaped rings of cartilage—to keep trachea open

Lined with ciliated mucous membrane

Coughing and expectoration gets rid of dust-laden mucous

Bronchi and BronchiolesBronchi and Bronchioles

Lower end of trachea divides into right and left bronchus

Bronchi—similar to trachea with ciliated mucous and rings of cartilage

As they enter lungs divide into smaller bronchial tubes

Bronchial tubes have cartilaginous plates instead of rings

Bronchial tubes lead to even smaller bronchioles

Bronchioles—thinner walls of smooth muscle

At the end of the bronchiole is the alveoli

Bronchi, Bronchial Tubes and Bronchi, Bronchial Tubes and BronchiolesBronchioles

AlveoliAlveoli

Composed of single layer of epithelial tissue

Inner surfaces covered with SURFACTANT (keeps alveoli from collapsing)

Each alveolus is surrounded by capillaries

Oxygen and carbon dioxide exchange takes place between alveoli and capillaries

LungsLungs

Fill thoracic cavity Upper part—apex Lower part—base Lung tissue is porous

and spongy—it floats Right lung—larger

and shorter (displaced by liver) Has 3 lobes

Left lung—smaller (displaced by heart) Has two lobes

PleuraPleura

Thin, moist, slippery membrane that covers lungs

Double-walled sac Space is pleural cavity

—filled with pleural fluid to prevent friction

Pulmonary Ventilation Pulmonary Ventilation (Breathing)(Breathing)

Inspiration Intercostal muscles

lift ribs outward Sternum rises Diaphragm contracts

and moves downward This increases the

volume of the lungs and air rushes in

Expiration (exhalation) Opposite action takes

place Exhalation is a passive

process

Breathing ProcessBreathing Process

Respiratory MovementsRespiratory Movements

1 inspiration + 1 expiration = 1 respiration

Respiratory rate for normal adult is 14-20

Factors that Affect Respiratory Factors that Affect Respiratory RateRate

Increases with exercise, fever, certain diseases

Age—newborn = 40-60 per minuteSleep—respirations decreaseEmotion can increase or decrease

CoughingCoughing

Deep breath followed by forceful expulsion of air—to clear lower respiratory tract

HiccupsHiccups

Spasm of the diaphragm and spasmotic closure of the glottis

Caused by irritation to diaphragm or phrenic nerve

SneezingSneezing

Air forced through nose to clear respiratory tract

YawningYawning

Deep prolonged breath that fills the lungs and increases oxygen within the blood

Control of BreathingControl of Breathing

Controlled by neural and chemical factors

Neural Factors Respiratory center in

medulla oblongota Increase in carbon

dioxide or decrease in oxygen will trigger respiratory center

Then the phrenic nerve stimulates the diaphragm

Chemical Factors Depends on levels of

carbon dioxide in blood Chemoreceptors in aorta

and carotid arteries are sensitive to the amount of oxygen in blood