Week 1 (parts 1 and 2) Flashcards
What makes up the upper respiratory tract
Nose (mouth), Pharynx and Larynx
What makes up the lower respiratory tract
Trachea, Bronchi, Bronchioles, Alveoli
what 3 parts is the pharynx split into
nasopharynx (air), oropharynx (air+ food), Laryngopharynx (air+ food, site of bijurication)
larynx functions/ facts
larynx is protected form food by Epiglottis that closes over the larynx during swallowing, contains vocal cords (essential for effective cough)
What 3 parts are the Bronchi split into
Primary (main), Secondary (lobar), Tertiary (segmental)
what 2 zones are the bronchioles split up into
Conducting zone, Respiratory zone
where does the trachea descend from and to
from larynx into the thorax (situated anteriorly to the oesophagus)
what are the different parts of bronchi
Right and Left primary bronchi, Secondary (lobar) bronchi, Tertiary (segmental) bronchi
what is the structure of the left and right main bronchi
R - branches off at 20-30 degrees, wider and shorter than L
L - branches off at 45-55 degrees
what is the structure and function of the secondary and tertiary bronchi
secondary - main bronchi divides into secondary bronchi, Right = 3 and L = 2, supply each lobe of the lung
Tertiary - Secondary bronchi divide into tertiary bronchi, Right = 10 L = 9, supply each segment of the lung
where does gaseous exchange occur
Alveoli of lungs
what are the branches of the lungs
Trachea - Primary Bronchus - Bronchial Tree, Terminal Bronchi - Bronchioles - terminal bronchioles - respiratory bronchioles
what are the lobes of the right lung (3)
upper/superior, middle, lower/inferior
what are the lobes of the left lung (2)
upper/ superior, lower/inferior
(smaller due to position of heart)
what are the right and left lung lobes divided by
fissures: (right - oblique and horizontal) (left - oblique)
what covers the lungs
pleural membrane (pleura)
what is the outer layer of the pleura called
parietal pleura - lines inner surface of the thoracic wall and superior surface of the diaphragm
what is the inner pleura layer called
visceral pleura - covers the outer surface of the lungs and lines the fissures
what is the space between the outer and inner pleura layers called
pleural cavity - contains pleural fluid
functions of pleural fluid
acts as a lubricant allowing the layers to glide over each other during inspiration and expiration, increases surface tension/ locks 2 pleural layers together
what makes up the thoracic cage
ribs, sternum, thoracic vertebra
how many pairs of ribs are there
12 pairs in total: pairs 1-7 (true ribs) articulate with vertebra and sternum,
pairs 8-10 (False ribs) articulate with vertebra and indirectly with sternum, pairs 11-12 (floating ribs) articulate with vertebra no attachment anteriorly to sternum
which ribs are typical and atypical
typical = 2-9
atypical = 1,10,11,12
what are the three elements of the sternum
manubrium, body, Xiphoid process
what is the structure of typical ribs
posterior end = head +tubercle
anterior end = continuous costal cartilage which articulates with sternum
rib 1 structure
flat in the horizontal plane, broad superior and inferior surfaces, articulates with the body of T1only
bony landmarks:
scalene tubercle, grooves, costal cartilage
alveoli structure
channels of martin (bronchiole-bronchiole)
Canals of Lambert (bronchiole-alveolar)
Pores of Kohn (alveolar-alveolar)
3 different sternocostal joints
- joints between rins 1-7 (true ribs) and sternum
- Rib 1 and the manubrium (fibrocartilaginous joint)
- ribs 2-7 synovial, surrounded by thin capsules
interchondrial joints
ribs 7-10, synovial joints, occur between costal cartilages of adjacent ribs, provide anchorage to the sternum
muscles active during inspiration
diaphragm
external intercostals
Accessory muscles:
Sternocleidomastoid
Scalenes
Pec minor and major
Muscles active dring forced expiration
- internal intercostal
- rectus abdominis
- Transversus abdominis
- internal and external obliques
origins of the diaphragm
costal part: lower margin of costal arch (inner surface ribs 7-12)
Lumbar part:
medial - L1-L3 vertebral bodies and intervertebral discs (2nd and 3rd), anterior longitudinal ligament
Lateral - arcuate ligaments (median, medial and lateral)
Sternal part:
Posterior surface of xiphoid process
what is the insertion point of the diaphragm
central tendon
what is the innervation of the diaphragm
phrenic nerve (C3,C4,C5)
relaxed inspiration process
- Controlled by autonomic nerve impulses from the respiratory centre in the brainstem
- Nerve stimulation causes contraction of the diaphragm and the external intercostals this expands the thoracic cage and lungs
- Expansion creates a lower pressure relative to the outside of the body
- Although only a small difference (gradient) the low resistance properties of the airway ensures efficiency
- Air rushes in
Biomechanics of breathing
Pump handle:
- Primarily involves upper ribs and sternum
- Increases the anterior-posterior dimension of the chest
Bucket Handle:
- Primarily involves the lower ribs
- Increases the transverse diameter of the chest
how pump and bucket handle works
During inhalation, both pump handle and bucket handle movements occur simultaneously, allowing for maximum expansion of the chest cavity and intake of air.
The relative contribution of each movement can vary depending on breathing patterns and individual anatomy.
during forced inspiration what do the accessory muscles do
assist deep inspiration and assist during episodes of respiratory distress
also help to elevate the rib cage
is relaxed expiration a passive or active process
passive - relaxing of the diaphragm and external intercostal muscles, allows for elastic recoil of lung tissue
examples of forced expiration
cough, sneeze, physical exertion
what happens during forced expiration
contraction of the abdominal muscles causes the abdominal contents to push up against the diaphragm - reduces the vertical diameter of the thorax
contraction of the internal intercostal depress the ribs and decrease space in the thorax
what is bradypnoea
An abnormally slow respiratory rate (below 12 breaths per min)
what is hyperventilation/ tachypnoea
shortness of breath/ shallow breathing
what is apnoea
e.g sleep apnea, repeated lapses in breathing due to a partially or completely blocked airway
what is agonal breathing
Abnormal pattern of breathing characterised by laboured, gasping breaths that occur because of insufficient oxygen
what is orthopnoea
shortness of breath when lying down
what is kussmaul respiration
abnormal breathing at a rapid and deep rate (signals respiratory distress)
what is cheyne-stokes breathing
compensatory reflex that allows the body to quickly restore oxygen levels
WEEK 1
Module introduction
PULMONARY A AND P (PP 2)
what part of the brain controls breathing
respiratory control centers in the brainstem
what are the 4 respiratory control centers in the brainstem
Inspiratory centre (medulla)
Expiratory centre (medulla)
Pneumotaxic centre (pons)
Apneuristic centre (pons)
where do medullary resp centres provide output to
respiratory and muscles and pontine centres
Occurs automatically without any concious effort
what are the factors controlling breathing
cerebral cortex can exert voluntary control over breathing as well as centres involved in emotion and pain
Peripheral chemoreceptors in vascular system and central chemoreceptors in brain detect changes to oxygen and carbon dioxide levels
stretch receptors in lungs and activity receptors in muscles and joints
characteristics of the airways
large surface area to enable efficient gaseous exchange
Tissues have intrinsic elastic properties to make the processes of breathing energy efficient
Rich blood supply for gaseous exchange
Fluid lubrication ensure rapid diffusion and counteract physical forces such as surface tension
what are the main gases in the body
oxygen (required for sustainable energy production) and carbon dioxide (can become toxic to cells at high levels)
what is bulk flow
movement of air from the atmosphere to alveoli (occurs due to pressure difference during inspiration in alveoli where alveoli pressure is less than the atmospheres)
What is diffusion of gas
movement of molecules from alveoli - blood - cell - blood - alveoli (occurs due to a high to low pressure gradient)
what does partial pressure mean
the concentration of each gas in the body
what are partial pressures measured in
kilopascals (kPa) or millimetres of mercury (mmHg)
what is the symbol for partial pressure of oxygen/ carbon dioxide in the air
PO2/PCO2
what is the symbol for the partial pressure of oxygen dissolved in plasma of arterial blood
PaO2
what is the symbol of partial pressure of carbon dioxide dissolved in plasma of venous blood
PvCO2
what are the factors affecting gas solubility (3)
Partial pressure of gas - the greater the partial pressure the faster it will dissolve into the liquid phase
Partial pressure of gas in liquid phase - If the partial pressure of a gas in the liquid phase becomes higher than its partial pressure in the gas phase, some of the dissolved gas will re-enter the gas phase
Solubility of a gas - E.g. CO2 is 20x more soluble in water than O2, so more will be dissolved at a lower partial pressure
where does gaseous exchange in the lungs occur
respiratory membrane (the alveolar airspace and the blood capillaries)
what three factors affect Gaseous exchange in the lungs
- gas partial pressure and gas solubility
- matching of alveolar ventilation with pulmonary blood perfusion
structural characteristics of the respiratory membrane
what is Ventilation (V)
volume of air entering the alveoli
What is Perfusion (Q)
volume of blood flowing through the lungs
what is V/Q mismatch
inadequacy of V or Q will significantly impact the oxygenation of the blood and the removal of CO2
in a healthy adult where in the lung is ventilation most optimal
lower 1/3 of the lung AKA dependent lung region
what do the upper (non-dependent) lung regions do
they have a greater initial volume e.g the alveoli are already expanded with little capacity for volume change
in a healthy self-ventilating adult lung where is perfusion most optimal
lower 1/3 of the lung AKA dependent lung region
what is perfusion influenced by
gravity, interaction of alveolar arterial and tissue pressure
why is the respiratory membrane able to enhance gaseous exchange
large surface area due to large number of lung alveoli
Very thin membrane so small depth for diffusion (1-2000ths of a millimetre)
what are the 2 ways oxygen is transported in the body
bound to haemoglobin in RBCs (98.5%)
Dissolved in plasma (1.5%)
what is haemoglobin composed of
4 polypeptide chains each bound to a haem group
what is the process of oxygen transport
- Hb molecule can combine with 4 molecules of O2 forms oxyhaemoglobin (no O2 = deoxyhaemoglobin
- Oxygen binds with the haem molecules
- once the first molecule is attached the molecule changes its shape and increases O2 binding capacity
- Affinity of Hb for O2 changes according to the O2 saturation
how much O2 is reversible bound or released is determined by
- Partial pressure of oxygen in blood (PO2)
- Temperature
- Blood pH
- The partial press of CO2 (PCO2) and therefore concentration of H+ ions
- blood concentration of BPG produced by RBC
how much carbon dioxide do respiring cells produce a minute
200ml
what are the 3 ways blood carries CO2 to the lungs
- dissolved as CO2 in blood plasma (7-10%)
- Chemically bound to Hb in RBCs as carbaminohaemoglobin (20%)
- Bicarbonate ions in plasma (roughly 70%)
Haemoglobin (20%)
- rapid reversible reaction
- CO2 binds to globin portion of molecule forming carbaminohaemoglobin
- O2 binds with the haem portion = no competition but deoxyhaemoglobin combines more readily with CO2
- CO2 rapidly disassociates from Hb in the lungs when PCO2 in alveoli is lower than in the blood
- CO2 is loaded in the tissues where PCO2 is higher than in the blood
Bicarbonate ions (roughly 70%)
- series of chemical reactions in plasma or RBCs (majority in RBCs)
- CO2 rapidly diffuses into RBCs where it combines with water to form carbonic acid
- This reaction is 1000x faster in RBCs due to the action of an enzyme called carbonic anhydrase
- Carbonic acid produced is highly unstable and quickly disassociates into hydrogen ions and bicarbonate ions
- When hydrogen ions are released, they in turn bind to haemoglobin and facilitate the release of oxygen
respiration chemical reaction
CO2 + H20 <—->H2CO3 <—> H+ +HCO3-
