Respiratory Lectures (8) Flashcards
4 primary functions of respiratory system?
L1
- Exchange of gases b/n atm and blood
- homeostatic regulation of body pH
- protection from inhaled pathogens and irritating substances
- vocalization
Air exchange occurs via ____.
L1
Bulk Flow
- blood flows from high to low pressures
- muscular pumps create pressure gradient (heart)
- resistance influenced most by diameter of tube that air is flowing through (length same, viscosity rarely changes in blood)
Why is it hard to breathe in a sauna?
L1
Air is more viscous (more water in it)
External Respiration
L1
movement of gases (mostly O2 and CO2) b/n enviro and cells
External Respiration steps
L1
- inhalation and exhalation -> exchange of air from atm to lungs & vice versa (ventilation)
- exchanging fresh O2 with CO2 into and out of body (lungs to blood) @ alveoli
- transport of gases in blood
- exchange of blood into the cells
Respiration requires coordination b/n ____.
L1
Respiratory and cardiovascular systems
:when you breathe slower your heart rate slows
Structures involved in ventilation and gas exchange
L1
→ conducting airways (upper and lower respiratory system)
→ alveoli
→ bones and muscles of thorax cavity (create force to move air)
Order the upper and lower respiratory system structures in order
L1
Nasal cavity pharynx larynx trachea (first of lower) L and R bronchi bronchioles alveoli
Where is the site of gas exchange in lungs?
L1
Alveoli
Bones and muscles in the thorax cavity
L1
Walls = spine, ribs, sternum, muscles Floor = diaphragm
What are the muscles of inspiration?
L1
Thorax cavity
-sternocleidomastoids, scalenes, external intercostals, diaphragm
What are the muscles of expiration?
L1
Thorax cavity
-internal intercostals, abdominals
Lungs composed of?
L1
light spongy tissue filled mostly by air-filled sacs (ALVEOLI)
- right lung slightly bigger than left (3 lobes)
- left has 2 lobes = cardiac notch
- each lung surrounded by pleural sac
Composition of pleural sac
L1
double-walled
- one layer connected to surface of LUNGS = visceral pleura, or wall of lungs (inside)
- other one connects to surface of thoracic CAVITY and DIAPHRAGM at bottom = parietal pleura (outside)
What’s the point of the pleural sac?
L1
- create moist slippery surface and prevent lungs from rubbing on walls during inhalation/exhalation (can move a bit)
- hold lungs to thoracic wall so they stay in an OPEN state since they are muscle tissue and naturally want to recoil (collapsed lungs)
How much fluid is inside the pleural sac?
L1
~10-20ml of fluid in entire lung since very small space b/n visceral and parietal layer
path air travels b/n coming into nasal cavity/mouth and ending in the alveoli
L1
nasal cavity → pharynx → larynx (vocal cords) → trachea (windpipe, semiflexible tube held open with ~20 cartilage rings) →L and R bronchi (going to L and R lungs) → smaller bronchi → bronchioles (no more cartilage on them, only smooth muscle, control amount of air coming to alveoli) → alveoli (air exchange)
Velocity of air ___ as it goes down the respiratory system.
L1
Decreases → important for alveoli to be able to properly do airflow exchange
- branching imc total cross sectional area
- velocity of air flow inversely proportional to total cross sectional area, V = Q/A
- only bronchioles and alveoli are exchange surfaces. All others are part of conducting system
Upper airways and bronchi play important role in _____.
i.e. Jobs?
L1
→ warm air to body (so body temp doesn’t fluctuate)
→ adding water vapor (alveoli need to be moist so gases can diffuse across → SALINE)
→ filter out foreign materials (traps them)
the 3 processes of upper airways and bronchi are more efficient with ___.
L1
Nose breathing:
→ nasal cavity has bigger SA, rich in blood supply and hair
→ shape of it allows air to come in fast so particles embed in mucus in back of pharynx and slide down to esophagus
Air is filtered in the ___.
Describe mucocillary escalator.
L1
Trachea and bronchi
→ saline produced by epithelial cells. Overtop saline is layer of mucus produced by goblet cells. Mucus contains immunoglobulins to neutralize pathogens
→ mucociliary escalator: cilia in epithelial cells beat, push saline up so it pushes mucus with pathogens into pharynx and down to stomach
What is necessary for the mucociliary escalator to function?
L1
Saline
→ without saline layer, cilia become embedded in thick mucus and unable to move which can lead to infections, scarring of airways, inability to breath
Describe the CFTR channel
L1
Model of saline secretion by epithelial cells
→ A NKCC channel brings 2 Cl into epithelial cell from ECF
→ As 2 Cl- enter the epithelial cell, creates -ve charge
→ Na+ moves from ECF to cell paracellularly
→ this Na and Cl movement creates [ ] gradient for water to move from ECF to cell
→ anion channel on apical membrane allows Cl to enter lumen
*K that enters epithelial cell is removed by K channel
Cystic Fibrosis
L1
Autosomal recessive mutation in gene making CFTR (cystic fibrosis transmembrane conductance regulator)
→ less saline production: less Cl transport
→ mucus can’t be cleared properly, bacteria colonizes airways: recurrent lung infections
→ life expectancy ~40 yrs
→ affects pancreas (name: formation of cysts and fibrosis of pancreas)