Respiratory System Flashcards
What are the functions of the respiratory system
-moves air to and from lungs
-gas exchange between air and circulation blood
-protects the surface of the respiratory tract
-defence against invading pathogens
-relays olfactory sensations from nasal cavity to cns
-helps control body fluid pH
-provides sounds involved in speaking, singing and non verbal communication
What is the upper respiratory system made from
Nose, nasal cavity, paranasal sinuses, pharynx, larynx
What is the lower respiratory system
Trachea, bronchi, bronchioles, alveoli
What body parts make up the conducting portion of the respiratory tract
-entrance to mouth and nasal cavity
-pharynx
-larynx
-trachea
-bronchi
-bronchioles
-terminal bronchiholes
What parts of the body make up the respiratory portion of the respiratory tract
-respiratory bronchioles
-alveoli
What does the conducting portion do
Filters, warms and moistens air
Transmits air to and from the lungs
What does the respiratory portion do
Site of gas exchange
What are vibrasse in the nose
Hairs at external nares
What are the internal nares openings to
Pharynx
What is the nasal cavity lined with
Pseduostraitied ciliated columnar with goblet cells line nasal cavity for removal of particles
What are the serous glands in the nose for
Humidifies air
What is the conchae for in the nose
Bony projetions slows down air flow
What are paranasal sinuses for in the nose
Lightens the skull and provides speech resonance
What is the olfactory epithelium for in the nose
Sense of smell
Larynx
-connects the pharynx with the trachea
-cartilaginous skeleton covered by muscle and membranes
What is the function of the larynx
-maintains an open airway
-prevents food and drink entering the lower respiratory tract
-during swallowing the larynx is pulled upwards and the epiglottis moves down to cover laryngeal inlet
-cough reflex
Vocal folds
-formed from the free border of the cricovocal membrane
-extends between the arytenoid and thyroid cartilages
-lie either side of the glottis
Trachea
-tough flexible tube
-extends from the cricoid cartilage to the carina
-lies anterior to oespophagus
-lined by pseudostratified ciliated columns epithelium with goblet cells
-supported by c shaped cartilage rings which prevent it from collapsing
-trachealis muscle joins end of the cartilages posteriorly
Trachea lining
-fine hair like ciliary cells
-covered with thin layer of mucous that catches forgin material produced by goblet cells
-cilia rhythmically beat and move the mucous material up the pharynx where it can be swallowed or eliminated from the body
Primary bronchi
-begin at the carina
-supply each lung
-2-3cm long
-right is wider and more vertical than left
-c shaped cartilages
Secondary bronchi (lobar)
-the loungers at the hilum
-3 on the right and 2 on the left
-supply the lobes of the lung
Tertiary bronchi
Supply segments of the lung 10 on the right and 8 on the left
Bronchioles
-no cartilage
-smooth muscle=can constrict and dilate
-each gives rise to 50-80 terminal bronchioles
Terminal bronchioles
-simple columnar epithelium with cilia
-no goblet cells or mucous glands
-each gives rise to 2 or more respiratory bronchioels
Respiratory bronchioles
-simple cuboidal epithelia
-no cilia
-alveoli extends from the lumen so gas exchange can occur herw
Alveoli
-gas exchange
-surrounded by capillary network for gas exchange
Right lung
-shorter and broader than left lung
-handles 55% of gas exchange
-3 lobes, superior, middle, inferior
-2 fissures, oblique and horizontal
Left lung
-narrower and longer than the right lung
-2 lobes superior and inferior
-1 fissure, oblique
Pleura
Double layered serous membrane, totally encloses each lung
Parietal layer
Lines inner surface of chest wall and upper surfaces of diaphragm (lines outside of the lung attached to the chest wall)
Visceral layer
Hugs/ surrounds the entire lung surface
Pleural cavity
Area between visceral and parietal layers which contains thin film of serous fluid
-lubricants pleural surfaces allowing them to slide smoothly against each other as the lungs expand and contact
-creates a bond between the layers that causes the lungs to move with the chest wall during breathing
Thoracic wall
-consists of bony skeleton
-bony skeleton 12 pairs of ribs, 12 thoracic vertebra
-sternum
-muscles- diaphragm, intercostals, accessory muscles
-supports and protects the lungs allowing them to expand and contact
What is respiration
Exchange off gases between atmosphere, blood and cells
What are the 3 steps of respiration
-pulmonary ventilation
-external pulmonary respiration
-internal tissue respiration
Explain pulmonary ventilation (breathing)
Inspiration and exhalation of air between atmosphere and lungs (alveoli)
Blood gains oxygen and looses carbon dioxide
Explain External (pulmonary) respiration
Exchange of gases between alveoli and blood in pulmonary capillaries
Explain internal tissue respiration
Exchange of gases between blood in systemic capillaries and tissue cells
Blood loose oxygen and gains carbon dioxide
CO2 is generated from cellular respiration
What is boyles law
When the temperature of a gas is constant the pressure of the gas varies inversely with volume
Volume decreases= pressure increases
Volume increases= pressure decreases
Relate boyles law to pulmonary ventilation
Air will enter the lungs when atmospheric pressure is greater than intrapulmonary pressure
Air will leave the lungs when intrapulmonary pressure is greater than atmospheric pressure
Altering the volume of the lungs alters the pressure
Intrapleaural pressure
-refers to the pressure within the pleural cavity
-always lower than atmospheric and intrapulmonary pressures
-created by elastic recoil of the lungs
How can thoracic volume be increased
-increasing vertical diameter
-increasing anterior posterior diameter
-increasing transfers diameter
Increasing vertical diameter
-contraction of diaphragm increases vertical diameter
-responsible for 75% increase in thoracic capacity
Ap and transverse diameters
-elevation of ribs at the sternal end makes the more horiztontal and pushes sternum forwards-increasing AP diameter
-many of the ribs are lower near their middle and rise at each end like the handle of the bucket
-if the middle of the rib rises, it moves away from the midline of the body-increases transverse
Role of the pleura in ventilation
Surface tension between parietal and visceral pleaura ensured that they cannot be pulled apart, therefore increase in thoracic volume increases lung volume
Quiet inspiration
-diaphragm contracts then flattens
-responsible for 75% increase in thoracic volume
-external intercostal muscles elevate ribs and increase the transverse and AP diameters
Quiet expiration
-passive procès due to lung recoil (elastic lungs to back to normal volume)
-diaphragm relaxes upwards
-external intercostals relax
-dependant on:elastics recoil of chest walls and lungs and surface tension (pulls inward)
Forced inspiration
-accessory muscles help out when required
-in fit people during exercise
-in sick people doing almost nothing
-accessory muscles
What are the accessory muscles
Scalenes, sternocleidomastoid, pectoralis major and minor, serratus anterior
Forced expiration
-internal intercostals
-abdominal muscles
Modified respiratory movements
-used to express emotions
-clear passageways
-sneezing, yawning, hiccuping, sobbing, laughing
-reflexes, some can be initiated voluntarily
Neural control of ventilation
-chemoreceptors detect change in po2, pco2 &pH and exist in the brain
-chemoreceptors send signals to respiratory centres in the brain stem
-via the vagus and glossopharyngeal nerves (afférent pathways)
-from respiratory centre to muscles of ventilation
-through phrenic, intercostal and other nerves (efferent pathway)
Hearing Breuer reflex
-prevents over inflation of the lungs
-stretch receptors in the visceral pleura, bronchioles and alveoli
-impulses sent via vagus nerve to pneumotaxic centre
-duration of inspiration is shortened
How can lung volume be measures
Spirometer
Tidal volume
Volume of air inhaled or exhaled in one quiet breath
Inspiratroy reserve volume
Amount of air that can be forecibly inhaled after a normal tidal volume inhalation
Experiatory reserve volume
The amount of air that can be forcibly exhaled after a normal tidal volume exhalation
Residual volume
Air remaining in lungs after maximum expiration
External pulmonary respiration
-exchange of gases between alveoli and pulmonary blood capillaries
-gases diffuse from areas of high partial pressure to low partial pressure - driving force
What does external pulmonary respiration depend on
-partial pressure differences
-large surface area of alveoli
-small diffusion distance accross alveolar- capillary (respiratory) membrane
-solubility of gases
Internal (tissue) respiration
-exchange of gases between blood capillaries and tissues
-gases diffuse from areas of high partial pressure to low partial pressure to- driving force
-oxygen diffuse from oxygenated blood through interstitial fluid and into tissue fluids
Transport of oxygen
-in the blood
-1.5% dissolved in plasma
-98.5% is bound to haemoglobin as oxyhemoglobin
Transport of carbon dioxide
-in 3 forms
-7% dissolved in plasma
-23% bound to hémoglobine in red blood cells
-70% is bicarbonate ion in plasma
