Respiratory Flashcards
What is the function of the respiratory system
Conduct clean, warm and moist air in close proximity with the circulatory system’s blood for gas exchange
What structures make up the upper respiratory tract
Nose, nasal cavity, paranasal sinuses, pharynx
What structures make up the lower respiratory tract
Larynx, trachea, bronchi, bronchioles
Where does olfaction occur
Nasal cavity
What is mucosa
Epithelium attached via basement membrane to lamina propria (connective tissue)
What type of epithelium is in the nasal cavity
Respiratory and olfactory
What type of epithelium is in the pharynx
Stratified squamous
What type of epithelium is in the trachea
Pseudostratified columnar
What type of epithelium is in the bronchioles
Simple cuboidal
What type of epithelium is in the alveoli
Simple squamous
What is respiratory epithelium
Pseudostratified ciliated columnar epithelium with goblet cells
Where is respiratory epithelium found
Nasal cavity, part of pharynx, larynx, trachea, bronchi
What is the purpose of ciliated cells in respiratory epithelium
Push mucus toward pharynx
What are the parts of the pharynx
Nasopharynx, oropharynx, laryngopharynx
What are the purposes of the paranasal sinuses
Resonating chambers for speech, lighten skull, increased SA to clean, warm, moisten air, infected mucus blocks drainage
What is the purpose of nasal cartilage
Maintain patent (unobstructed) airway
What’s the fancy name for nostrils (openings)
External nares
What is the nasal vestibule
Passageway
What is the name of the hairs in the nasal vestibule
Vibrissae
What does the vestibule have in it
Sebaceous and sweat glands, hair follicles
What forms the roof of the nasal cavity
Ethmoid and sphenoid bones
What forms the floor of the nasal cavity
Hard (top of mouth) and soft (back of throat) palates
What are the projections in the nasal cavity called and what is their function
Superior, middle and inferior conchae, function to spin air to increase time for warming and humidifying, plus olfactory detection
Where are olfactory receptors located
Roof of nasal cavity
What is olfactory epithelium and where is it located
Olfactory mucosa containing olfactory receptors, nasal cavity
What is the vascular plexus
Network of blood vessels which helps to warm incoming air. When air temperature drops plexus dilates for greater heat transfer. Nose bleeds usually originate from damage here
Where are the paranasal sinuses located
Within frontal, sphenoid, ethmoid and maxillary bones
What are paranasal sinuses lined with
Respiratory mucosa
Where do paranasal sinuses drain into
Pharynx
What is the nasopharynx lined with
Respiratory mucosa
What structures define the nasopharynx
Internal nares to soft palate
What prevents food from entering the nasopharynx
Soft palate and uvula
Where is the auditory tube and what is its function
Drainage from the middle ear
Where are the pharyngeal tonsils (adenoids)
Posterior wall of pharynx
What are the three types of tonsils
Pharyngeal, palatine, lingual
Where is the palatine tonsil
Posterior and inferior to soft palate
Where is the lingual tonsil located
Back of tongue
What is the name of the bone at the top of the trachea
Hyoid
What structures define the oropharynx
Soft palate to hyoid bone
What structures define the laryngopharynx
Hyoid bone to opening of larynx/beginning of oesophagus
What structure prevents food from entering the trachea
Epiglottis (glottis = voice box)
What defines the larynx
Hyoid bone to trachea
What are the three cartilaginous structures in the larynx and what is their purpose
Epiglottis, thyroid cartilage, cricoid cartilage, function to protect and maintain an open airway
What are the vocal folds
Folds attached to thyroid cartilage which vibrate with passing air to produce normal phonation
How are male vocal folds different
Testosterone affects cartilage and muscle, resulting in longer, thicker folds and a deeper voice
What are the vestibular folds
Superior to vocal folds, prevent foreign object entry to glottis, can produce very deep sounds
What connects the C shaped cartilage of the trachea
Trachealis (band of smooth muscle)
What is the mucociliary escalator
Pseudostratified columnar cells move mucus with trapped debris against gravity to clear pharynx. Mucous cells and mucous glands
Describe the shape and position of the lungs
Apex extends to just above clavicle, dome shaped base sits on top of diaphragm
Describe the branching of the bronchial tree
Trachea, primary bronchi, secondary bronchi, tertiary bronchi, bronchioles, lots of branching, terminal bronchioles
How does the cartilage change in the primary bronchi
Cartilage becomes complete rings
How does the cartilage change in the secondary and tertiary bronchi
Becomes irregular plates
How does the cartilage change in the bronchioles (<1mm)
Thick smooth muscle for bronchoconstriction/dilation
What do terminal bronchioles supply (<0.5mm)
Pulmonary lobule
What are pulmonary lobules
Made of alveoli arranged like bunches of grapes
Describe the alveolar wall
Simple squamous epithelium on a thin basement membrane
What is the external surface of the alveoli covered with
Fine network of pulmonary capillaries
What are the two types of pneumocytes (lung epithelial cells)
Type 1 squamous and Type 2 cuboidal
What are type 1 squamous pneumocytes
Form respiratory membrane/blood-air barrier with capillary wall and shared basement membrane
What are type 2 cuboidal pneumocytes
Scattered amongst type 1, secrete surfactant, a complex lipoprotein that reduces the surface tension of the alveolar fluid
What is the third type of cell present in the alveoli
Roaming macrophage: remove debris that makes it to alveoli
What lines the lines
Pleura (serous membrane: double layer of secretory tissue with fluid between layers)
What are the boundaries of the thoracic cavity
Sternum, thoracic vertebrae, ribs, base of neck, diaphragm
What is the mediastinum
Heart, vessels, pericardium
How are pressure and volume related
Pressure is inversely proportional to volume (P = 1/V)
What type of joints are the sternocostal joints
All synovial except the first which is cartilaginous
What type of joints are the costochondral joints
Cartilaginous
What type of joints are the interchondral joints
Synovial
What type of joints are the costotransverse joints
Synovial
What type of joints are the costovertebral joints
Synovial
What are the primary muscles of respiration
Diaphragm and intercostals
When are the accessory muscles needed
For deep, forced breathing
What happens when you contract your diaphragm
It flattens, more space in thoracic cavity
What happens when you relax your diaphragm
It becomes more dome shaped, less space in thoracic cavity
What do the external intercostals do
Lift ribcage and expand cavity
Inspiration: quiet and forced
What do the internal intercostals do
Depress ribcage and decrease cavity (relax to enable normal exhalation: a passive process)
Expiration: forced only
What angle are the external intercostals
Hands in pockets
What angle are the internal intercostals
Opposite of hands in pockets
What are the function of rib cage accessory muscles
Increase cavity volume for forced inspiration, decrease cavity volume for forced expiration
What is the purpose of the pleura
Make lungs stick to thoracic wall to ensure lungs expand as thoracic cavity does, slippery surface for frictionless movement against other structures, fluid bond causes lungs to stick to thoracic wall
What is the driving force for air into the lungs
Pressure gradient
What are the two forces that must be overcome to take a breath
Stiffness of the lungs and resistance of the airways to the lungs
What is compliance
ΔV/ΔP
What is the condition of too stiff lungs called
Pulmonary fibrosis (cannot accommodate large change in volume)
How is the surface tension of the lungs overcome
Surfactant secreted by type 2 pneumocytes
How is resistance related to luminal radius
R = 1/r^4 (rule of 16)
What is a restrictive respiratory disorder
Reduced lung capacity: reduced lung compliance or insufficient surfactant release
What is an obstructive respiratory disorder
Resistance to airflow e.g asthma, chronic bronchitis
What is tidal volume
Volume of air moved in and out during normal quiet breath
What is inspiratory reserve volume
Extra volume that can be inspired with maximal inhalation
What is expiratory reserve volume
Extra volume that can be exhaled with maximal effort
What is residual volume
Volume remaining in lungs after maximal exhalation
What is minimal volume
Volume remaining in lungs if they collapsed (smashed down alveoli)
What is vital capacity
Inspiratory reserve + expiratory reserve + tidal volume. Volume of air you can shift in and out of your lungs
What is total lung capacity
Vital capacity + residual volume. Total Volume in lungs when filled to the max
What is inspiratory capacity
Inspiratory reserve + tidal volume. Total volume of air you can inspire from rest
What is functional residual capacity
Expiratory reserve + residual volume. Volume remaining in lungs after normal exhalation.
What is FEV1
Forced expiratory volume in one second (how much of the vital capacity comes out in the first second). Reduced with diseases causing resistance to airflow
What is the FEV1/VC ratio
Measure to detect obstructive illnesses. Normal ~0.8, <0.7 indicates airway obstruction
What is the formula for cardiac output
CO = SV * HR
What is the formula for respiratory minute volume (how much air do we breathe in and out per minute)
Ve = Vt * f
Respiratory minute volume (L/min) = tidal volume (L/breath) * respiratory rate (breaths/min)
What is the dead space
Volume of air stuck in pathways (can’t undergo gas exchange as not in alveoli. Much of what you exhale is dead space.)
What is the formula for alveolar ventilation
Va = (Vt - Vd) * f
alveolar ventilation = (tidal volume (breathing strength) - dead space (air that can’t be used)) * respiratory rate
Does atmospheric pressure equal pressure in the alveoli
Pressure in alveoli is lower, must be a gradient for gases to move into the lungs
What is the partial pressure of CO2 in the alveoli
40mmHg
What is the partial pressure of O2 in the alveoli
100mmHg
What determines the rate of diffusion
Surface area of membranes, thickness of membranes, pressure difference between two sides
What is the condition where alveolar spaces are dilated resulting in a decrease in surface area?
Emphysema
What does the blood air barrier consist of
Alveolar cell layer, fused basement membrane, capillary endothelium
How is the correct level of oxygen inhaled
Lower blood oxygen = greater gradient for diffusion, higher blood oxygen = smaller gradient for diffusion
What is the approximate partial pressure of oxygen in blood moving toward and away from the alveoli
~40mmHg moving toward, ~100mmHg moving away
What is the approximate partial pressure of carbon dioxide in blood moving toward and away from the alveoli
~46mmHg moving toward,
~40mmHg moving away
What are the two ways oxygen can be transported in the blood
Dissolved and bound to haemoglobin in RBCs
What is the relationship between oxyhaemoglobin saturation and PO2
Sigmoidal due to cooperative binding of oxygen molecules
Why is it good that the binding curve is sigmoidal
Good at binding O2 at high partial pressure, good at releasing at low partial pressure. Designed to keep blood O2 high in case of an emergency
What is the average PO2 in active muscle tissue
~15mmHg
What does a right shift in the binding curve indicate
Reduced haemoglobin O2 affinity
What can cause a right shift in the haemoglobin curve
Lowered pH, higher temperature
How does exercise result in more oxygen being released into tissue
pH drops and temperature rises (reduced O2 affinity)
What is the process called chloride shift
Exchange of bicarbonate for Cl- (Cl- into cell)
How can CO2 be transported in the blood
Dissolved in plasma, bound to haemoglobin, converted to bicarbonate
How is bicarbonate formed
Carbon dioxide and water combine to form carbonic acid (catalysed by carbonic anhydrase), carbonic acid dissociates into hydrogen and bicarbonate ions, lowering the pH of the blood
How are CO2 and O2 normally kept within close limits
Tight control of ventilation
What is the central controller of breathing
Pons, medulla and other parts of the brain
What are the sensors reporting to the brain to affect the rate of breathing
Chemoreceptors, baroreceptors, lung stretch receptors, protective reflexes
Where are the chemoreceptors for breathing and what do they detect
Arteries and medulla oblongata, stimulated by increased PCO2 and decreased pH (specific receptors for O2 and CO2, CO2 bigger impact)
What are baroreceptors and where are they located
Blood pressure sensors, located on the carotid artery and aorta
What is the general relationship between arterial blood pressure and respiratory minute volume
Opposite effect between the two
What is the purpose of stretch receptors in the lungs
After receiving afferent input, the brain sends efferent output preventing the lungs from stretching too far either way. Also detect irritation and trigger a sneeze or cough
