week 14: respiratory system

function of respiratory system

• supply oxygen to the body

• remove carbon dioxide from body

• filter, warm, and moisten air

components of respiratory system

• nose

• larynx

• trachea

• bronchial tree

• lungs

• diaphragm

upper respiratory tract

• conducting zone

• all respiratory pathways

• contains nasal cavity, pharynx, and larynx

• cleanse, humidify, and warm incoming air

lower respiratory tract

• respiratory zone

• site of gas exchange bronchioles and microscopic structures

• infections are more serious

• contains trachea, primary bronchia, and lungs

pneumonid

infection of small bronchioles

bronchitis

viral infection of larger airway

primary functions of nose

• produce mucus (1qt a day)

• sweep mucus w/ dirt into throat (cilia)

• resonance chamber for speech

• houses smell receptors (CN1)

components of nose

• root

• alae

• nares/nostrils

• nasal septum

nares

opening from nasal cavity into pharynx (internal holes)

nostrils

external openings of nose

root of nose

space between eyebrows

ala of nose

lateral outside parts of nose

external nose

• nasal bones

• frontal bone

• maxillary bones

• cartilage

nasal cavity

• septal cartilage anterior midline

• ethmoid and vomer posterior midline

• roof formed by ethmoid and sphenoid

• floor is formed by soft and hard palates

• lined with mucus

deviated septum

• crooked septum caused by trauma or congenital

• causes difficulty breathing, headache, bloody nose, snoring

• fixed by surgery

pharynx

• connects nasal cavity to mouth, larynx, esophagus

• fibromuscular tube that serves respiratory and digestive systems

• bounded above by sphenoid and posteriorly by bodies of cervical vertebrae

• opens anteriorly into nasal cavity, oral cavity, larynx

• in throat, 5 inches long

nasopharynx

• posterior to nasal cavity, superior to soft palate

• only an air passageway because it is superior to oral cavity

• closed off by soft palate and uvula during swallowing to prevent food from entering nasal cavity

• pharyngeal tonsils sit at back to trap and destroy air pathogens

• auditory tubes empty into it to equalize pressure

oropharynx

• posterior to oral cavity and continues to the throat

• from the soft palate to the epiglottis or hyoid bone

• both food and air pass through the oropharynx

• palatine (lateral walls) and lingual tonsil (base of tongue) lie in it

laryngopharynx

• inferior part of pharynx posterior to epiglottis

• leads to esophagus and larynx

• food and air pass through it

• air has right of way during swallowing and air flow stops

• hyoid bone to lower border of cricoid cartilage

• walls made of pharybgeal constrictor muscles that help swallow

epiglottis

• elastic cartilage in glottis opening

• directs food to esophagus

• covered by taste buds w/ mucus

thyroid cartilage

• large shield made by 2 plates

• midline is laryngeal prominence

• adam’s apple

cricoid cartilage

• inferior to thyroid

• ring shape on top of trachea

• anchors larynx to trachea

arytenoid cartilage

• on posterior wall

• anchors vocal folds

larynx

• voice box

• provides airway and switching mechanism for food and air

• 2 inches long and made of 9 cartilages/connective tissue

• attaches to hyoid bone superiorly/trachea inferiorly

laryngitis

• swelling of vocal cords

• interferes with vibration and causes hoarseness and inability to speak above whisper

vocal folds

• vibtrate as air rushes up from lungs producing sound

• length of folds and size of glottis and arytenoid cartilage pulling on fold change to produce diff sounds

• tenser cords = higher pitch

• puberty in males causes folds to become longer and thicker

• loudness depends on force air is expelled based on chest and abdomen

trachea

• air passageway windpipe that is 4 inches long

• descends from larynx through neck in the mediastinum held open by C shaped cartilages

• flexible and mobile

• inferior end is carina and then branches into 2 brachia

bronchial tree

• air passageways into the lungs

• two main or primary bronchus

• tree branches up to 23 times

• where conducting zone turns into respiratory zone for gas exchange

left and right primary bronchi

run obliquely and plunge into hilum of lungs

secondary (lobar) bronchi

• run into each of the lobes of lungs

• 3 lobes on right and 2 on left

tertiary (segmental) bronchi

once inside each lobes of lungs

bronchioles

• terminal bronchioles are smallest that contain cartilage

• give rise to individual respiratory bronchioles exchange of gases at this level

• end in alveoli sacs that have individual alveoli

alveoli sacs

• thin walled alveoli are covered with blood vessels

• they receive air

lungs

• paired cone shape organs that flank mediastinum in thorax

• made of fibrous elastic connective tissue that allows it to expand then recoil passively with expiration

apex of lungs

superior, narrow tip of lungs just deep to clavicle

base of lungs

concave inferior surface that rests on diaphragm

costal surface

anterior lateral and posterior surfaces that are in contact with the ribs

mediastinal surface

internal surface that faces internal cavity of thorax

hilum

depression on lungs where blood vessels and bronchi enter

left lung

• slightly smaller due to heart (cardiac notch)

• 2 lobes (superior and inferior)

• oblique fissure separates lobes

right lung

• larger than left lung

• 3 lobes (superior, middle, inferior)

• oblique and horizontal fissure (separates superior and middle lobes)

lung cancer

• lobules with blacked edges

• lung cancer is responsible for more cancer deaths than other type of cancer

• smoking responsible for 85%

pleura

thin double walled sac around lungs

parietal pleura

• covers thoracic wall and superior face of diaphragm

• holds lung in place

• outer layer

visceral pleura

• covers external lung surface and dips into fissures

• inner layer

pleural cavity

• cavity between each layer that is filled with fluid

• allows for lubrication of lungs

• easily glide over thorax wall during breathing

• separates into 3 segments to keep organs from moving

• prevents spread of infection between areas

pneumonia

• excessive fluid produced and retained in pleural cavity

• exerts pressure on lungs, hard to breathe

asthma

• similar to bronchitis but irreversible inflammation

• 1 in 10 people have it

• caused by irritants and allergens

• treat with inhaler or steroids

emphysema

• caused by smoking and hereditary

• causes heavy breathing and permanent enlargement of alveoli and destruction of lung walls

• lungs lose elasticity and other muscles are required for breathing

• uses 15-20% of body energy instead of 5%

• bronchioles and capillaries broken

pulmonary embolism

• obstruction of artery or vessel in lungs

• blood clot

• most often from lower extremity into heart into pulmonary circulation

• sudden death if no blood flow