RS Lec 1 Flashcards
Respiratory system major function
-provides O2 + eliminates CO2
Respiratory system minor functions
- protects against microbial infection (filtering action)
- regulates blood pH with kidneys
- phonation: production of vocal sound/speech
- olfaction: sense of smell
- reservoir for blood
Structures that make up the respiratory system
- upper airways
- trachea
- lungs (bronchi –> bronchioles –> alveoli)
- muscles of respiration
- ribcage + pleura
- CNS
trachea anatomy
- C shape cartilage (anterior-front)
- smooth muscle (posterior-back)
primary bronchi anatomy
-plates of cartilage & smooth muscle
bronchioles + terminal bronchioles anatomy
smooth muscle
Airways beyond larynx divided in 2 zones:
- conducting zone
- respiratory zone
Conducting zone
- leads gas to gas exchanging region of the lungs
- anatomical dead gas (150 ml)
- no alveoli=nog gas exchange
Respiratory zone
where gas exchange occurs
-has alveoli
Terminal bronchioles
-smallest airay without alveoli (conducting zone)
Respiratory bronchioles
-has alveoli (respiratory zone)
23 generations of respiratory system
- trachea=0
- bronchi=1
- terminal bronchioles= 5-16
- respiratory bronchioles= 17-19
- alveolar sacs= 23
↑ generations…
- ↑ number, ↑ total cross-sectional area
- ↓ diameter size
Order of structures in lung
- trachea
- bronchi
- bronchioles
- terminal bronchioles
- respiratory bronchioles
- alveolar ducts
- alveolar sacs
Order of structures in lung- conducting zone
- trachea
- bronchi
- bronchioles
- terminal bronchioles
Order of structures in lung- respiratory zone
- respiratory bronchioles
- alveolar ducts
- alveolar sacs
alveoli (def.)
-tiny, thin walled, capillary-rich sac in lungs for O2 + CO2 exchange
alveoli and capillaries (number)
- 500 million in human lungs (1/3 mm in diameter), highly vascularized
- 280 billion capillaries (70 ml of blood at rest, 200 ml working)
Alveoli surface
- lined by continuous monolayer type I alveolar cells (most of surface)
- type II alveolar cells (7%)
Type I alveolar cells
- most of alveoli
- does not divide, easily harmed by toxins
Type II alveolar cells
- produce surfactant (detergent: contains lipoproteins)- reduce surface tension of alveolar fluid
- progenitor cells in injury to type I cells, multiply + differentiate into type I cells
network of capillaries (alveoli)
- 7-10 um in diameter (enough space for RBC)
- small interstitial space (connective tissue + interstitial fluids)
RBC time in capillary network
-0.75 s – passes 2-3 alveoli
thickness of respiratory membrane
- 0.2- 0.5 um thick _esaily damaged - transfer O2+ CO2 (diffusion)
Steps of respiration
- Ventilation
- Exchange of O2 + CO2 between alveoli + blood in capillaries (diffusion)
- Transport of O2 + CO2 through blood (bulk flow)
- Exchange of O2 + CO2 in tissues (diffusion)
- Cellular respiration
Ventilation (def.)
exchange of air btw atmosphere + alveoli by bulk flow due to changes in gas pressure
Ventilation steps
- CNS sends excitatory signals to respiratory muscles
- Muscles contract rhythmically
- Changes in volume + pressures at chest & lung
- Air flows in and out the lungs
Respiratory muscles types
- pump muscles
- airway muscles
- accessory muscles
inspiratory pump muscles
- diaphragm
- external intercostals
- parasternal
expiratory pump muscles
- internal intercostals
- abdominals
inspiratory airway muscles
- tongue protruders (genioglossus)
- alae nasi
- muscles arounds airways (pharynx, larynx)
expiratory airway muscles
-constrictors muscles around airways (pharynx, larynx)
inspiratory accessory muscles
- sternocleidomastoid
- scalene
- pectoralis
diaphragm (def.)
-dome shaped muscle that flattens during contraction (INS)
diaphragm action
abdominal contents are forced down and forward
-ribcage is widened = increase in volume of thorax
external intercostals action
-contract + pull ribs upward increasing lateral (sideways) volume of the thorax- “bucket handle motion”
parasternal intercostals action
-contract + pull sternum forward, increase anterior posterior dimension of ribcage- “pump handle motion”
abdominals list
- external oblique
- internal oblique
- rectus abdominis
- transversus abdominis
abdominals regular function
-relaxed at rest, involved in other physiological functions (coughing, vomiting, defecation, posture)
(abdominals) deeper, faster breathing requires
- active contraction of abdominal & internal intercostal muscles to return lung to resting position (exercise)
Internal intercostal muscles action
- relaxed at rest
- exercise: pull ribcage down, ↓ thoracic volume
Accessory inspiratory muscles
- contribute very little to quiet breathing at rest
- contract vigorously during exercise/forced respiration
sternocleidomastoid action
-raise the sternum
scalenes action
-elevate upper ribs
pectoralis
-elevates ribs
regular (quiet) inspiration
- external intercostal muscles pull ribs up and out
- diaphragm contracts
forced inspiration
- sternocleidomastoid elevates sternum
- pectoralis minor elevates ribs
- diaphragm contracts more
regular (quiet) expiration
- diaphragm relax
- abdominal organs recoil and press diaphragm upward
forced expiration
- abdominal wall muscles contract + press organs upward into diaphragm
- posterior internal intercostals pull ribs down and inward
Upper airways muscles contribute to
-opening the upper airways + reduce airway resistance
Upper airway muscles list
- tongue protruders
- alae nasi
- pharyngeal and laryngeal dilators (inspiratory)
- pharyngeal and laryngeal constrictors (expiratory)
obstructive sleep apnea definition
-reduction in upper airway openness (patency) during sleep
obstructive sleep apnea symptoms
snoring, apneas, sleep disturbances
obstructive sleep apnea causes
- anatomical defects
- reduction in muscle tone
obstructive sleep apnea treatment
CPAP (continuous positive airway pressure)- mask over nose to keep air passage open
conducting airways are lined with..
superficial layer of epithelial cells
epithelial cells in airways (types)
- goblet cells (mucus-producing)
- ciliated cells
epithelial cells in airways function
-work together to entrap inhaled biological + inert particulates and remove them the airways
ciliated cells produce
pericilliary fluid (sol layer)
sol layer
- aka periciliary fluid
- low viscosity (good for ciliary action)
- thickness (5um)
Goblet cells produce
mucus (5- 10 um thick gel layer)
gel layer
- high viscosity, high elastic properties
- trap inhaled materials
cilia movements in nasopharynx
-downward
cilia movements in trachea
-upward
smoke reduces
-activity of cilia + increases number of goblet cells
macrophages
- last defense to inhaled particles
- phagocytize foreign particles + substances
pulmonary fibrosis
- macrophages phagocytize silica dust +asbestos
- fibroblast recruitment + collagen accumulation
