The Respiratory System
- Created by: Uxia Lorenzo
- Created on: 05-01-13 11:35
Respiration
O2 enters body and CO2 is eliminated pulmonary ventilation
gas exchange in lungs
blood transport
gas exchange in tissues
control of ventilation
The conducting always = gas exchange does not occur
carrys air to and from area involved in gas exchange
moistening and cleaning inhaled air
2 parts
Upper Respiratory tract
Nasal cavity - divided by nasal septum
air enters respiratory tract via nose
lined by skin with sebaceous and sweat glands Hair act as fillers
each lateral wall has bony elevations
superior/middle/inferior nasal conchae
air steam passes ove conchae
small dust particles precipate out
all but vestibules lined by mucous
covered by columner epithelium (goblet cells)
mucous and serous glands, secret1L of fluid per day
serous glands - lysosome
Pharynx
tube of skeletal muscle
3 regions - nasopharynx, oropharynx, larynopharynx
air passes with nasopharynx from cavity
via 2 internal nares or chronae
nasopharynx lies above palate- closed off during swallowing
posterior wall - pharyngeal tonsils
oral cavity connects with oropharynx
Laryngopharynx - lies behind eplglottis
connects orophaynx with oesophagus
pathway for air and food
Lower Respiratory tract
comprises of larynx, bronchi, bronchioles
Larynx - upper frontal region of neck
betwen root of tongue
suspended from hyoid bone
aryteriod corniculates cunei forms
onicois epiglottis thyroid(adams Apple)
cartillages connected by intrinsic muscle
principles muscles used in phonation
transverve arteroid
lateral oncoarteroid, posterior oncaaryteroid, lined with mucous membrane with pharynx and trachea
Continued
glottis - the gap between vocal cords
V-shaped during quiet breathing
becomes rounded with inspiration
spiglottis - leaf shaped cartilage
reflected during swallowing
Tracheabronchial tree - trachea - divides and gives 2 bronchi
Posterior wall - trachealis muscle
contaction narrows airways
lined with goblet cells and mucosa
2 principles bronchus - wider, shirter and more vertically
right lungs gets infections
Respiratory part of lungs
Terminal bronchioles - alveoli
divides into two branches
Alveolar wall forms major part
thin and contains 2 types of cells
type 1 pheumocytes - gas exchange
type 2 - synthesize surfactant
elastic fibres surround alveoli
help tissue recoil during respiration
respiratory bronchiole and structures
functional unit of lung - pulmonary
Blood supply
lungs have a double circulation
pulmonary circulation
enables bloods o2 supply and CO2 supply to be eliminated
nourishes alveoli
bronchial circulation
blood flow through 2 lungs 5L/min
1L of blood within vessels
100 ml within capillary beds in gas exchange
Nerve Supply of the lungs
autonomic pathways to
bronchial smooth muscle
bronchial glands
sympathetic stimulation
bronchodilation
Na acts of beta2 adrenceptors
Parasympathetic
mild vasoconstriction of smooth muscle
stimulate increased secretion of glands
Pulmonary ventilation
lungs are passive
chest wall and diaphragm move
Inspiration - contraction of inspiratory muscle, volume of thorax increases
lungs stretch, intrathoracic pressure drops
lungs recoil, pressure rises
Muscles of respiration are skeletal
controlled by somatic and autonomic motor neurones
involuntary but controlled
Pleurae
2 serous membrane
parietal pleaura- outer membrane to part of chest wall and diaphragm
visceral pleaura, inner membrane covers wing
surfaces are smooth and covered in fluid
2 membranes separated by fluid film
pressure in cavity is subatomospheric
negative
if chest wall is punched, air enters cavity
pleaurae separate
lung collapses chest wall expands
traumatic phenomothorax
Inspiration
diaphragm and external interocstal muscles
Diaphragm- striated muscles
connected to central tendon
flattens due to stimulation
thoracic cavity height
irritation of phrenic nerve - hiccups
external interocstal muscles
connected adjacent rivs
bow shaped lower ribs up and down
AP and lat diameters of thorax increased
Expiration
Quiet expiration - passive process
diaphragm moves up
pressure in Aveoli rise
air pushed out
Forced Expiration - abdominal muscles contract
intra abdominal pressure increased
diaphragm forced up
air expelled actively from lungs
Lung Volumes
Tidal volumes (TV) - air that enters or leaves at each breath
Inspiratory reserve volumes (IRV)
air taken in by maximum respiratory effort over and above a resting expiration
expiratory (ERV)
extra vol of air expired
residual volume (RV)
air left in lungs after deep expiration
Lung Capacity Formulas
Lung capacity Formulas
Inspiratory Capacity (IC) max volume of air inhaled
IC = RTV + IRV
Functional residual capacity (FRC)
volume of air left in lungs at the end of expiration FRC=RV + ERC
Vital Capacity (VC) - gas expelled by deepest expiration
VC=IRV+RTV+ERV
Total lung capacity (YLC)
Vol of air held in system TLC=VC and RV
Other Respiratory Function valves
Minute volume - air breathed per min
Fioced expiratory volume - gas expelled over time
Airway resistance - flow of air through a tube is raised by and increase in length
Peak expiratory flow rate maximal flow
Lung compliance
Inspired air - O2,N2,CO2,H2O - trace gases
Alveolar gases recieves CO2 from bloo
gives up to O2 to blood
Expired gas - same as atmospheric air
Control of Ventilation
metabolic (automatic) - basic pattern
can be overidden (holding breath)
controller in brain stem
behavioural (voluntary)
Respiratory centre
medulla and pans contain groups of neurones
medulla- inspiratory centre (dorsal)
expiratory centre (ventra) - only included in forced expiration
Pneumatic centre
located in upper pans
controls breathing rate
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