RESPIRATORY SYSTEM

Respiratory System functions

Upper respiratory tract

composed of mainly of hyaline cartilage

extends from nares (nostrils) to choane

openings to pharynx hard palate is its roof

• air filled spaces within bone
• open into nasal cavity
• Sinusitis

• on each side of nasal cavity
• increase surface area of nasal cavity
• help in cleaning, humidifying, warming of air

• carry tears from eyes
• open into nasal cavity

a common passageway for the respiratory and digestive systems

takes in air

extends from uvula to epiglottis takes in food, drink, and air

• extends from epiglottis to esophagus
• food and drink pass through

• “little grape”
• extension of soft palate

aids in defending against infections

Lower Respiratory Tract

Located in the anterior throat and extends from the base of the tongue to the trachea.

cartilages in larynx

• largest piece of cartilage
• called Adam’s apple

• piece of cartilage
• flap that prevents swallowed materials from entering larynx

• source of voice production
•air moves past them, they vibrate, and sound is produced
• force of air determine loudness
• tension determines pitch

inflammation of vocal folds caused by overuse, dry air, infection

How does the epiglottis prevent aspiration of foods and liquids?

• Windpipe
• Consists of 16 to 20 C-shaped pieces of cartilage
• Contains cilia pseudostratified columnar epi.
• Smoking kills cilia

_________ dislodges materials from trachea

Divides into right and left primary bronchi (lungs)

an operation to make an opening into the trachea.

• Divide from trachea
• Connect to lungs
• Lined with cilia
• Contain C-shaped pieces of cartilage

• Primary organ of respiration
• Cone shaped
• The base rests on the diaphragm
• The apex extends above the clavicle
• Right lung has 3 lobes Left lung has 2 lobes
• Contains many air passageways

Lung airway passages

• small air sacs
• where gas exchange occurs
• surrounded by capillaries
• 300 million in lungs

contraction of terminal bronchioles leads to reduced air flow

• in lungs where gas exchange between air and blood occurs
• Formed by walls of alveoli and capillaries
• Very thin for diffusion of gases

double-layered membrane around lungs

membrane that lines thoracic cavity

membrane that covers lung’s surface

Reminder!

• a process of moving air in and out of the lungs
• uses the diaphragm, which is a skeletal muscle that separates the thoracic and abdominal cavities

Phases of ventilation

• breathe in
• uses the diaphragm and the external intercostal muscles

• breathe out
• uses the diaphragm

uses internal intercostal muscles

Right now, what is the main muscle that is powering your breathing?

What muscles involved during exercise of forceful breathing?

• Diaphragm descends and rib cage expands
• Thoracic cavity volume increases, pressure decreases
• Atmospheric pressure is greater than (high) alveolar pressure (low)
• Air moves into alveoli (lungs)

• Diaphragm relaxes and rib cage recoils
• Thoracic cavity volume decreases, pressure increases
• Alveolar pressure is greater than (high) atmospheric pressure (low)
• Air moves out of lungs

is the tendency for an expanded lung to decrease in size

is due to elastic fibers and thin film of fluid lining alveoli

occurs during quiet expiration

keeps lungs from collapsing

is a single fluid layer on the surface of thin fluid lining alveoli thus reduces surface tension

is produced by secretory cells of the alveoli

too little surfactant

drugs for a mother that has little surfactant

• pressure in the pleural cavity
• less than alveolar pressure
• keep the alveoli from collapsing

intoduction of air into the pleuarl cavity.

Factors that Influence Pulmonary Ventilation

• lungs need to recoil between ventilations
• decreased by emphysema

• expansion of thoracic cavity
• affected if rib cage is damaged

• occurs during an asthma attack, infection, tumor

Pulmonary volumes

device that measures pulmonary volumes

• volume of air inspired and expired during quiet breathing
• 500ml

• volume of air that can be inspired forcefully after a normal inspiration
• 3000ml

• volume of air that can be expired forcefully after a normal expiration
• 1100ml

• volume of air remaining in lungs after a maximal expiration (can’t be measured with spirometer)
• 1200ml

amount of air remaining in the lungs at the end of of a normal expiration(2300ml)

? = ERV + RV

amount of air a person can inspire maximally after normal expiration (3500ml)

? = TV + IRV

max. amount of air a person can expire after a max. inspiration(4600ml)

? = IRV + ERV + TV

sum of inspiratory and expiratory reserves and the tidal and residual volumes (5800)

? = VC + RV

Factors that Influence Pulmonary Volumes

• where gas exchange between blood and air occurs primarily in alveoli and pulmonary capillaries
• some in respiratory bronchioles and alveolar ducts
• does NOT occur in bronchioles, bronchi, trachea(anatomical dead space)
• influenced by thickness of membrane, total area of membrane, partial pressure of gases

Respiratory membrane thickness

• increased thickness decreases rate of diffusion
• Pulmonary edema decreases diffusion
• Rate of gas exchange is decreased
• O2 exchange is affected before CO2 because CO2 diffuse more easily than O2

Surface Area

• Decreases surface of respiratory membrane to 1/4 or 1/3 can restict gas exchange.
• Possible reasons are surgical removal of lung tissue.lung cancer, emphysema.

• the pressure exerted by a specific gas in a mixture of gases
• the total atmospheric pressure of all gases at sea level is 760 mm Hg
• the atmosphere is 21% O2

Partial Pressure

• the partial pressure for O2 is __________
• the upper case letter P represents partial pressure of a certain gas (Po2)

Factors of O2 release from oxyhemoglobin

• Normal respiratory rate is 12 to 20 respirations per minute (adults).
• In children, the rates are higher and may vary from 20 to 40 per minute.
• The rhythm is controlled by neurons in the medulla oblongata.
• Rate is determined by the number of times respiratory muscles are stimulated.

• inhibits respiratory center when lungs are stretched during inspiration
• touch, thermal and pain receptors in the skin