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Concept Map: 09 Respiratory System Viriahelyn Calvillo P:6 -…
Concept Map: 09 Respiratory System Viriahelyn Calvillo P:6
Major Functions of the respiratory system
supply blood with O2 for cellular respiration and dispose of CO2, a waste product of cellular respiration
-also functions in olfaction and speech
Involves four processes:
Respiratory system:
pulmonary ventilation (breathing):
movement of air into and out of lungs
External respiration:
exchange of O2 and CO2 between lungs and blood
Circulatory system:
transport of O2 and CO2 in blood
Internal respiration:exchange of )2 and CO2 between systemic blood vessels and tissues
Upper respiratory structure and functions
nasal cavity
divided by midline nasal septum
septum is formed anteriorly by septal cartilage, and posteriorly by vomer bone and perpendicular plate of ethmoid bone
found with in and posterior to external nose
nasal vestibule:nasal cavity superior to nostrils
lined with vibrissae (hairs) that filter coarse particles from inspired air
rest of nasal cavity lined with mucous membranes, pseudostratified ciliated columnar epithelium
ciliated cells sweep contaminated mucus posteriorly towards throat
Paranasal sinuses
form ring around nasal cavities
located in frontal, sphenoid, ehtmoid, and maxillary bones
Functions:
lighten skull
Secrete mucus
help to warm and moisten air
Nose
only external portion of respiratory portion
Function
provides an airway fro respiration
moistens and warms entering air
filters and cleans inspired air
serves as resonating chamber for speech
houses olfactory receptors
Dvided into two two regions: external nose and nasal cavity
External Nose
areas include: root (area between eyebrows); bridge, dorsum nasi (anterior margin), and apex (tip of nose)
nostril (nares): bounded laterally by alae
Nasal conchae
scroll-like, mucosa covered projections that protrude medially from each lateral wall of nasal cavity
shape of conchae help to:
increase mucosal area
enhance air turbulence
Function:
filter, heat, and moisten air
Lower Respiratory structure and function
Larynx
(voice box): has 3 functions:
provides patent airway
routes air and food into proper channels
voice production
houses vocal folds
extends from 3rd to 6th cervical vertebra and attaches to hyoid bone. Opens into laryngopharynx and is continuous with trachea
Function: provides patent airway, routes air and food into proper channels, voice production
Trachea
extends from larynx into mediastinum , where it divides into two main bronchi
wall composed of 3 layers
mucosa
ciliated pseudostratified epithelium with goblet cells
submucosa:
CT with seromucous glands that help produce the mucus "sheets" within trachea, supported by 16-20 C-shaped cartilage rings that prevent collapse of trachea
adventitia
outermost layer made of CT
Bronchi and branches
respiratory zone structures
beings where terminal bronchioles feed into respiratory bronchioles, which lead into aveolar ducts and finally into alveolar sacs (succules)
alveolar sacs contain clusters of alveoli
300 million alveoli make up most of lung volume
sites of actual gas exchange
Respiratory membrane:
blood air barrier that consists of alveolar and capillary walls along with their fused basement membranes
very thin; allows gas exchange across membrane by simple diffusion
alveolar walls consist of:
single layer of squamous epithelium
scattered cuboidal alveolar cells secrete surfacant and antimicrobial proteins
Lungs and alveoli
Root: site of vascular and bronchial attachment to mediastinum
Costal Surface: anterior, lateral, and ppsterior surfcaes
Apex: superior tip, deep to clavicle
Base: interior surface that rests on diaphragm
Hilum: found on mediastinal surface, it is the site for entry/exit of blood vessels, bronchi, lymphatic vessels and nerves
Diaphragm
Broken in 2 zones:
Respiratory zone: site of gas exchange
consists of microscopic structures such as respiratory bronchioles, alveolar ducts, and alveoli
Conducting zone: conduits that transport gas to and from gas exchange sites
includes all other respiratory structures
cleanses, warms, and humidifies air
Later of Pleuarae
thin, double layered serosal membrane that divides thoraic cavity into 2 pleural compartments and mediastinum
Parietal Pleura: membrane on throaic wall, superior face fo diaphragm , around heart, and between lungs
Visceral pleura:
membrane on external lung surface
Pleural Fluid fills slitlike pleural cavity between two pleurae
provides lubrication and surface tension that assists in expansion and recoil of lungs
Compare and contrast the mechanism of inspiration and expiration
External
(pulmonary gas exchange) invloves the exchange of O2 and CO2 across respiratory membranes
partial pressure gradient and gas solubilities
steep partial pressure gradient for O2 exists between blood and lungs
venous blood P o2= 40mm Hg
Alveolar P o2=104 mm Hg
drives oxygen flow into blood
equilibrium is reached across respiratory membrane in .25 sec but it takes red blood cells . 75 sec to travel from start to end of pulmonary capillary
ensures adequate oxygenation even if blood flow increases 3x
Inspiration
active process involves inspiratory muscles
Action of the diaphragm: when dome-shaped diaphragm contracts, it moves inferiorly and flattens out. increase in thoracic volume
action of intercostal muscles: when external and intercostals contract, rib cage is lifted up and out. results in increase in thoracic volume
Volume and Pressure relationships in thoracic cavity
atmospheric pressure
pressure exerted by air surrounding the body
760mm Hg at sea level =1 atmosphere
Intrapulmonary Pressure
pressure in alveoli
also called intra alveolar pressure
fluctuates with breathing
always eventually equalizes with P atm
Trans pulmonary Pressure
( P pul - P ip)
pressure that keeps lung spaces open
keeps lungs from collapsing
Intrapleural pressure:
pressure in pleural cavity
fluctuates with breathing
always a negative pressure
two inward forces promote lung collapse
lungs natural tendency to recoil because of elasticity , lungs always try to assume smallest size
Surface tension of alveolar fluid
surface tension pulls on alveoli fluid so it can reduce aveolar size
-one outward force tends to enlarge lungs
elasticity of chest wall pulls thorax outward
Respiratory volumes and capacities
Respiratory Volume:
Tidal Volume (TV):
amount of air moved into and out of lung with each breathe
averages - 500 ml
Inspiratory Volume (IV)
amount of air that can be inspired forcibly beyond the tidal volume (2100-3200 ml)
Expiatory reserve Volume (ERV):
amount of air that can be forcibly expelled from lungs (2100-1200 ml)
Residual Volume (RV):
amount of air that always remains in lungs
needed to keep alveoli open
Respiratory Capacities:
combination of 2 or more respiratory volume
Inspiratory capacity (IC): sum of TV+IRV
Functional residual capacity (FRC): sum of RV+ERV
Vital capacity (VC): sum of TV+IRV+ERV
Total Lung Capacity (TLC): sum of all lung volumes (TV+IRV+ERV+RV)
Gas exchange
External
diffusion of gasses between blood and lungs. (Pulmonary gas exchange) involves the exchange of O2 and CO2 across respiratory membranes
Internal
diffusion of gases between blood and tissues. Involves capillary gas exchange in body tissues
Disorders of the Respiratory System
Atelectasis:
lung collapse due to plugged bronchioles which cause collapse of alveoli
Tonsillitis
infected and swollen tonsils can block air passage in nasopharynx. making it necessary to breathe through the mouth
Laryngitis
inflammation of vocal folds that causes the vocal folds to swell. interfering with vibrations
Pleurisy:
inflammation of pleurae that often results from pneumonia. inflamed pleurae become rough, resulting in friction and stabbing pain with each breath