HUMAN ANATOMY: Respiratory System

respiratory system

brings in O2 to fuel cells and remove CO2, sound production, smell, protection via coughing and sneezing to keep airways clear

respiration

ventilation, gas exchange (internal and external respiration), and oxygen utilization by cells

external respiration

gas exchange between air and red blood cells in the lungs

internal respiration

gas exchange between red blood cells and body tissues outside of the lungs

conducting zone

transport air in and out of lungs, warm and humidify air, and filter out dust and other harmful particles; nasal cavity, pharynx, larynx, trachea, and primary bronchus

respiratory zone

site of gas exchange; respiratory bronchioles, alveolar ducts, and alveoli

support structures of external nose

nasal bones, hyaline cartilage, and dense connective tissue

nasal glads

serous cells secrete digestive enzymes to destroy bacteria; mucous cells

mucous membrane

epithelium + lamina propria

lamina propria

loose areolar CT (highly vascularized); warms air, source of nosebleeds

nasal cavity

pseudostratified ciliated columnar, goblet cells, and lamina propria

vibrissae

protective hairs that line external nares and vestibule

external nares and vestibule

nostrils

nasal conchae

bony ridges that cause air turbulence; assists with cleansing air

cribriform plate

lined with specialized receptor cells for smell

posterior nares

where the nasal cavity ends

paranasal sinuses

air filled pseudostratified ciliated columnar lined cavities in the bone that lighten the skull, warm and moisten air, and have a single opening into nasal cavity; frontal, ethmoid, sphenoid, and maxillary

nasal meatus

opening for sinus into nasal cavity

sinus infection

inflammation of epithelium caused by virus or bacteria causes over secretion of mucus blocking the meatus and creating a painful pressure within sinus

nasal septum

bone and cartilage structure that separates nasal cavity in half

deviated septum

typically the cartilage becomes misaligned which disrupts air flow into the cavity

nasopharynx

posterior nares to soft palate; pseudostratified columnar epithelium

oropharynx

soft palate to epiglottis; stratified squamous epithelium

laryngopharynx

epiglottis to larynx, connects pharynx with opening to larynx (air) and esophagus (food); stratified squamous epithelium

pharyngeal tonsils (adenoids)

lymphoid tissue in the nasopharynx; part of immune system

pharyngotmpanic tube

part of nasopharynx that connects to middle ear; equalizes pressure

palatine and lingual tonsils

lymphoid tissue in the oropharynx; immune response

tonsillitis

inflammation of palatine tonsils, can be painful and interfere with swallowing

larynx

air passage and voice production; cilia push mucus up towards esophagus

epiglottis

structure of the larynx made of elastic cartilage; covers larynx when swallowing food

thyroid

structure of the larynx made of hyaline cartilage; supports back of larynx and is an attachment point for vocal folds (bigger with lower voices)

cricoid

structure of the larynx made of hyaline cartilage; supports back of the larynx

arytenoid

structure of the larynx made of hyaline cartilage; anchors vocal cords posteriorly

vocal folds

elastic fibers covered by mucosa and suspended between thyroid and arytenoid, vibrate when air passes over; longer→ deeper

vestibular folds

folds of mucosa that support vocal folds

rima glottidis

space between open vocal cords; air passes through

glottis

vocal folds + rima glottidis

laryngitis

excess mucus and inflammation prevent proper vibration of vocal folds

trachea

flexible but strong connection to lungs; supported by hyaline cartilage rings and made up of pseduostratified ciliated columnar epithelium, goblet cells, and seromucous glands

smokers cough

cilia paralyzed by toxins in cigarette smoke causing a build up of mucus

adventitia

exists in the trachea opposed to a serous membrane

trachealis muscle

smooth muscle that completes back of trachea; can constrict and relax as a protective mechanism

carina

last ring of tracheal cartilage that branches into each lung, epithelial cells very sensitive to irritants and excess mucus, and initiated cough reflex

branching of bronchial tree

main (primary) bronchi → lobar (secondary) bronchi → segmental (tertiary) bronchi → bronchioles

main (primary) bronchi

lined with PCC, cartilage rings of trachea replaced by irregular cartilage plates, and right bronchus is wider shorter and more vertical than left

lobar bronchi

right has three and left has two

segmental bronchi

branch from lobar bronchi; each segment serves a bronchopulmonary segment

smooth muscle in bronchus

contracts and relaxed to regulate airflow; thins out as it travels through tree

bronchial asthma

irritation of epithelium by allergens, cold air, etc activate mast cells which results in: inflammation of mucous membrane, bronchioconstriction, and increase in mucus secretions

alveolar sac

cluster of alveoli on a duct

alveloi

increase volume of lungs and surface area for gas exchange; vascularized

respiratory membrane

alveolar epithelium, basal laminae, and capillary endothelium

alveolar epithelium

simple squamous

capillary epithelium (endothelium)

simple squamous

type 1 cells

simple squamous; primarily gas exchange

type 2 cells

cuboidal; secrete surfactant

surfactant

decrease surface tension and allow alveoli to inflate more easily

macrophages

trap inhaled particles and remove them from mucusa

alveolar pores

equalize pressure between alveoli

respiratory distress syndrome

type 2 cells are not fully functional until 35 weeks; premature infants have difficulty inflating collapsed alveoli