Respiratory System Flashcards
What is respiratory system
It consist of a system of tubes that delivers air into lungs. Oxygen diffuse into the blood and carbon dioxide diffuses out. It is considered as a cardiopulmonary system
Collaborates with urinary system to regulate the body’s acid base balance
Primary function
Gas exchange
Communication
Olfaction- smell
Acid base balance
Blood pressure regulation
Blood and lymph flow
Blood filtration
Expulsion of abdominal contents
Principle organs
Nose
Pharynx
Larynx
Trachea
Bronchi
Lungs
Zones of respiratory system
Conducting zone - air flow
Respiratory zone- gas exchange
Some authorities use
Upper and lower respiratory tract
The nose
Warm, cleans and humidifies inhaled air
Detects odour
Resonating chambers that amplifies noise
The pharynx (throat
The regions
Nasopharynx
Oropharynx
Larynogopharyx
All contribute to speech, breathing and swallowing
The larynx voice box
Primary function is to keep food and drink out of the air
Addition role: phonation the production of sound
Walk are muscular for swallowing and voice control
Epiglottis
Stops food and drink form reaching airway
Trachea (windpipe )
Rings of hyaline cartilage prevents tube from collapsing
Lung
Right lung
Smaller
Three lobes- superior middle and inferior
Left lung taller and narrower because of the heart
Has a indentation- cardiac impression
Two lobes inferior and superior
Bronchial tree
Branching system of air tubes in each lung
Right- slightly wider and more ventricle then left
Secondary lobar branches 3R and 2L
To segmental tertiary bronchi R=10 and L=8
Brochioles
Lack cartilage
Terminal brochioles
Respiratory bronchioles
Considered the beginning of the respiratory zone since alveoli participate in gas exchange
Divide into alveoli ducts
Alveoli
150 million alveoli in each lung providing 70m2 of surface for gas exchange
Cells of alveolus
- squamous type 1 alveolar cells- allow for rapid gas diffusion
- great type 2 alveolar cells- prevent lung collapse and easier inflammation
- alveolar macrophages (dust cells)
Alveoli
Respiratory membrane consist of ;
- squamous alveolar cells
- endothe
Pleurae
Lines the thoracic wall and forms the surface of the lung
It creates the expansion of the lungs and therefore the drop in pressure when the diagram contracts
The pleural fluid function
1 reduce friction
Acts as a lubricant allowing lungs to expand and contract
2 create pressure gradient by expanding the lungs when we inhale
3 compartmentalisation separates
What is pulmonary ventilation
Breathing
Consist of a repetitive cycle: one cycle of inspiration (inhaling) and expiration ( exhaling)
What is respiratory cycle
One complete inspiration and expiration
- quiet respiration: while at rest effortlessly and automatic
- forced respiration: deep, rapid breathing such as during exercise
What do respiratory muscles do
Breathing muscles change lung volumes and create differences in pressure relative to the atmosphere
Diaphragm
Prime mover of respiration
Contraction flattens diaphragm enlarging thoracic cavity and pulling air into lungs
Relaxation allows diaphragm to bulge upwards again compressing the lungs and expelling air
Accounts for two thirds of airflow
Flattening=
- increases the superior to inferior dimension of the thoracic cage
- pushes sternum and ribs enlarging the anterior to posterior dimension
Internal intercostal respiratory muscle
Enable forced expiration by depressing the ribs
External intercostal respiratory muscle
Increase/ decrease the size of thorax
The enlargement of the thorax allow the lungs to expand and fill with air
Intercosta (internal and external intercostals)
Stiffens the thoracic cage during respiration
Prevents it from caving inward when diaphragm descends
Contribute to enlargement and contraction of thoracic cage
Add about one third of the air that ventilates the lungs
Scalenes respiratory muscles
Synergist to diaphragm
Quiet respiration hold ribs one and two stationary
Neural control of breathing
Breathing depends on repetitive stimuli of skeletal muscles from brain
- skeletal muscles cannot contract without nervous stimulation
- breathing requires a coordination action of multiple muscles
- ceases if nerve connections to thoracic muscles are servered
Respiratory centre controllled by two levels of the brain
Cerebral and conscious
Autonomic and unconscious (medulla oblongata and pons)
Voluntary control
Sends impulses down corticosinal tracts to respiratory neurons in spinal cord, by passings brain stem
Limits
Breaking point when carbon dioxide levels rise to a point when automatic control overrides one’s will
Involuntary control
Respiratory nuclei in medulla oblongata
Ventral respiratory groups basically just giving you the normal breathing cycle and then the dorsal respiratory group is taking information from receptors and providing more flexibility and changing based on those receptors
Pons
Pontine respiratory group modifies the rhythm of ventral respiratory group and the dorsal respiratory group. It adapts the breathing to special circumstances. It adapts breathing to special circumstance such as sleep exercise vocalisation and emotional responses
Sensory receptors
Central chemoreceptors
Peripheral chemoreceptors
Stretch receptors
Irritant receptors
Atmospheric pressure drives respiration
760mm Hg at sea level or 1 atmosphere (1 atm)
Lower at higher elevations
Boyles law
If the lungs contain a quantity of a gas and the lung volume increases, their internal pressure (intrapulmonary pressure) falls
- if the air pressure falls below atmospheric pressure the air moves into the lungs
If the lung volume decreases intrapulmonary pressure rises
- if pressure rises above atmospheric pressure the air moves out of the lungs
Where does the voluntary control over breathing originate
Motor cortex of frontal lobe of the cerebrum
The dorsal, ventral and pontine respiratory group are all part of
Involuntary control over breathing
Which group serves as the primary generator of the respiratory rhythm
Ventral respiratory group
What role does the pontine respiratory group (PRG) play
Modifies the rhythm of VRG and DRG
What is the effect of an increas in resistance on the airflow rate in the lungs
Decrease airflow
What does the term pulmonary compliance refer to?
The ease of which the lungs expand and change volume
Charles law simple
Something that is warmer it gets bigger essentially
What is spirometry
Measurement of pulmonary ventilation
Measurement of pulmonary volume and rate of expired airflow
What is spirometry useful for
Diagnosing lung disease, improvemen, deterioration
Tests:
-Vital capacity
-Forced expiratory volume in 1 sec ( FEV 1)
-FEV1/FVC RATIO
Respiratory volume and capacities (4main)
- tidal volume: volume of air inhaled and exhaled in one cycle during quiet breathing (500mL)
- inspiratory reserve volume: air in excess of tidal volume that can be inhaled with max effort ( 3,000mL)
- expiratory reserve volume: air in excess of tidal volume that can be exhaled with max effort (1,200mL)
- residual volume : air remaining in the lungs after max expiration (1300mL)
- vital capacity: total amount of air that can be inhaled and then exhaled with max effort VC= ERV + TV + IRV (4700mL)
- inspiratory capacity: maximum amount of air that can be inhaled after a normal tidal expiration IC= TV+IRV(3500mL)
- functional residual capacity: amount of air remaining in lungs after normal tidal expiration FRC=RV+ERV(2500mL)
- total lung capacity: max amount of air the lungs can contain TLC=RV+VC(6000mL)
Look for in spirometry
Peak flow : max speed of expiration
Minute respiratory volume: amount of air inhaled per minute
Max voluntary ventilation: ventilation increases during heavy exercises
Composition of air
78.6% nitrogen
20.9% oxygen
0.04% carbon dioxide
0-4% water vapour, minor gases argon, neon, helium, methane and ozone
Deltons law
The total atmospheric pressure is the sum of the contributions of these individual gases
Seperate contribution of each gas in a mixture (partial pressure [P])
Gas transport
The processs of carrying gases from the alveoli to the systemic tissue and vice versa
Oxygen transport
- 98.5% bound to hemoglobin
-1.5% dissolved in plasma
Carbon dioxide transport
-90% is hydrated (carbonic acid)
-5% bound to the amino group of plasma proteins
- 5% dissolved in blood
Gas transport - oxygen
It is bound to hemoglobin
Hemoglobin- molecule specialised in oxygen transport (4 protein [ globin] portions)
Each with heme group which binds one O2 to the ferrous ion (Fe2+)
One hemoglobin molecule can carry up to 4 O2
Systematic gas exchange
The gas is making its way from the blood into the tissues in your body. So it’s unloading of oxygen making its way out of the blood and is loading carbon dioxide into the blood from the tissue through the systemic capillaries
We typically have one carbon dioxide that comes in for every one oxygen that goes out of the blood
CO2 loading
- CO2 diffuses into the blood
- carbonic anhydrase in RBC catalyst
CO2 + H2O -> H2 CO3 -> HCO3- H+
- chloride shift
• keeps reaction proceeding, exchanges HCO3- for CI-
• H+ binding to hemoglobin
Oxygen unloading
- H+ binding to HbO2 reduces its affinity for O2
• tends to make hemoglobin release oxygen
Alveolar gas exchange
We won’t oxygen coming into the blood and carbon dioxide coming out of the blood
Reaction that occurs in ten lungs are reverse of systemic gas exchange
What is residual volume
Air remaining in the lungs after maximum expiration
What does peak flow measure
Maximum speed of expiration.
Make someone blow as hard and fast as they can
What characterises an obstructive lung disease
Both FEV1 and FEV1 % are decreased
What is the principle of Dalton’s law as it applies to atmospheric pressure
The total atmospheric pressure is the sum of the contributions of individual gases
What is the definition of partial pressure
The seperate contributions of each gas in a mixture
How does the membrane thickness affect gas exchange in the alveoli
Thicker membrane makes it less efficient
What is the primary function of hemoglobin
Transport oxygen in the blood
How many oxygen molecules can one molecule of hemoglobin carry at maximum saturation
4
What happens through systemic gas exchange
The unloading of oxygen and loading of carbon dioxide at the systemic capillaries
What happens during alveolar gas exchange
The reactions are reverse of systemic gas exchange
Structures of the respiratory system- zone
- Conducting zone:
-nose
- pharynx
- trachea
- primary bronchi
- secondary (lobar) bronchi
• 3R $ 2 L
- tertiary (segmental) bronchi
• 10R& 8L
- terminal bronchioles - Respiratory zone
- respiratory bronchioles
- alveoli
( respiratory zone sure of gas exchange)
Larynx main function
Voice box allows u to talk
Function of respiratory system
Conducting zone
- airflow
Respiratory zone
- gas exchange
Mechanics of respiration
- Quiet breathing:
A) inspiration:
- active process
- muscular contraction
- prime mover: diaphragm
- synergist: external intercostals
B) expiration:
- passive process
- muscular relaxation/ recoil
- Forced breathing:
A) inspiration:
- active process
- prime mover: diaphragm
- synergist: external/ internal intercostals, scalenes, sternocleidomastoid, serrated anterior
B) expiration
- active process
- recuts abdominal, internal intercostal
Mechanics of respiration
Respiratory control centres
1.medulla oblongata
• dorsal respiratory group
•ventral respiratory group
2. Pons
• pontine respiratory group
Laws of respiration ( pressure, resistance, airflow):
1. Boyles law
• pressure and volume of a gas have an inverse relationship, when temperature is held constant
2. Charles law
• the volume of a gas is directly proportional to its temperature, provided that the pressure and the amount of gas remain constant.
3. Dalton’s law
• total pressure exerted by a mixture of gases is equal to the sum of the pressure that each gas would exert
4. Ficks law
• gas molecules diffuse across a membrane from an area of high concentration to an area of low concentration
How do we measure the respiratory system?
Spirometry
1. Vital capacity
• total volume
- FEV1
• amount you can expire in 1 second - FEV1%
•amount you can expire in one second as a ratio of capacity
A) volume
- tidal volume(TV)
- inspiratory reserve volume
- expiratory reserve volume
- residual volume
B).
- total lung capacity
- inspiratory capacity
- vital capacity
- functional residual capacity
Adjustments in gas exchange
- Ambient pH ( Bohr effect)
- promotes o2 unloading from hemoglobin to tissue - Partial pressure of oxygen (ambient PO2)
- Temperature
- an in temperature promotes oxygen unloading from hemoglobin - Bisphosphoglycerate(BPG)
5 Haldane effect
