Respiratory System

Top 2 functions of respiratory system

1.) gas exchange

2.) helps regulate blood pH

other functions of respiratory system

• filters inspired air

• produces vocal sounds

• excretes small amounts of water and heat

• contains receptors for sense of smell

external nares

opening to nasal cavities

functions of nose

• airway for respiration

• moistens and warms air

• filters and cleans inspired air

• resonating chamber for speech

• houses olfactory receptors

cell type lining respiratory tract in nose

(Respiratory mucosa)

• pseudostratified columnar epithelium

• can make mucous to trap particle breathed in and cilia help move it back out of body

what triggers sneezing

sensory nerve endings in nose

folds that help direct air in the nasal cavity

nasal conchae

internal naris

opening at back of nasal cavity, leads to pharynx

3 parts of pharynx

• nasopharynx

• orophayrnx

• laryngopharynx

nasopharynx

• lined w/pseudostratified columnar epithelium

• where opening of auditory tube (eustacean tube) is located

• pharyngeal tonsil is against its superior wall

what prevents food from going up into the nasopharynx?

soft palate & uvula

oropharynx

• where palatine and lingual tonsils are located

laryngopharynx

• posterior to epiglottis

function of pharynx

• passageway for food, liquid and air

where does food/liquid go after leaving pharynx?

esophagus

where does air go after leaving pharynx?

larynx

prevents food/liquid from going down larynx

epiglottis

type of cartilage epiglottis is made of

elastic cartilage

larynx

• voice box of body; produces sounds

• attaches to hyoid bone

• supported by 2 types of cartilage

2 types of cartilage supporting larynx

• thyroid cartilage

• cricoid cartilage

• both made of hyaline cartilage

anatomy of the larynx

look at image

what produces sounds in larynx?

vocal folds. (aka - vocal chords)

vocal folds are typically thicker and longer in __________

males

how are vocal folds attached to larynx?

• muscles/elastic ligaments attach them to cartilage

• can control tension of folds

ventricular folds

• part of the larynx above the vocal folds

• aka - “false vocal chords”

• Have a mucous membrane, just like vocal folds

glottis

space that opens up in larynx when muscles attached to vocal chords are relaxed

what happens when laryngeal muscles contract?

• they pull elastic ligaments tight

• vocal folds move into air passageway (other muscles relax folds)

• glottis narrows

• vibration of air against vocal folds produces sound

what body parts act together as a resonating chamber?

• pharynx, nose, mouth, paranasal sinuses

body parts that help us enunciate

• muscles of face, tongue, lips

the greater the air pressure in larynx=

the louder the sound

tension on vocal folds determines this

pitch

trachea

(aka - windpipe)

• passageway for air from larynx to bronchi/lungs

tracheal cartilage

• supports airway so it doesn’t collapse w/pressuire change

• c-shaped rings

bronchi

• passageway for air to flow into lungs

• formed by bifurcating trachea

• primary, secondary and tertiary bronchi

primary bronchi

• one goes to each lung

secondary bronchi

• one goes to each lobe of lung

• aka: lobular bronchi

Tertiary Bronchi

• branch again w/in each lobe

curve in the left lung where the heart fits

cardiac notch

why do blood vessels branch to each lobe?

• if something damages one lobe, the others are still functional

Flow of Air from Bronchi to site of air exchange

• primary bronchus

• secondary bronchus

• tertiary bronchus

• bronchioles

• Terminal Bronchiole

• alveolar duct

• alveolar sac

• alveoli

Where does gas exchange take place?

Alveoli and capillaries surrounding them

Alveolar Membrane cell type

• simple squamous epithelium

• it’s one cell layer thick, allowing for easy gas exchange

why do lungs stay inflated?

• negative pressure in pleural cavity

• presence of surfactant, substance that reduces surface tension of alveoli allowing them to remain open and expand during breathing

Pleurae (pleura, singular)

• the double layered membrane that surrounds lungs and lines chest cavity

• has a cavity btwn the two layers

• aka: serous membrane

visceral pleura

membrane that covers the exterior of the lung

parietal pleura

membrane that is up against the chest wall

pleural cavity

• space btwn the visceral pleura and the parietal pleura

• contains fluid (Serous fluid) which reduces friction

intrapulmonary pressure

• pressure within the lungs

• @ equilibrium w/atmospheric pressure (760mm Hg)

intrapleural pressure

• pressure within the pleural cavity (756 mm Hg)

• ALWAYS LESS than atmospheric pressure /intrapulmonary pressure

• if it wasn’t less, your lungs would collapse

What determines intrapleural pressure?

• elastic recoil of lungs (force inward)

• pleural fluid adhesion w/in pleural cavity (force outward)

Atelectasis

• lung collapse

• affects alveoli in particular

• usually due to surgery w/anesthesia but sometimes airway blockage

pneumothorax

• when air gets into the pleural cavity, causing lung to collapse either partially or fully

• air either leaks in from inside or outside body

hemothorax

• accumulation of blood in the pleural cavity

• usually due to chest trauma

• symptoms: chest pain, difficulty breathing, rapid heart rate

Boyle’s Law

volume of gas varies inversely with pressure