EK B2 Ch4 Respiratory COPY Flashcards
respiratory system 1
- Provides oxygen to circulatory system and gets rid of CO2**
- Provides O2 to circulatory system and releases CO2
- Composed of airways and lungs
air pathway
- Air enters through nasal cavity or mouth
- Nasal cavity warms and moistens air
- Nasal hairs and mucus filter and trap particles
- Mouth and nasal cavity connect to pharynx
- Larynx branches from pharynx and is covered by epiglottis
- Larynx connects to trachea (windpipe) larynx is voice box espoghagus, epoglotis suppose to flip over and cover trachea when we swallow, obviously don’t want food and water to go through these passages think upside down tree picture, branches get smaller and smaller
mucus and cilia
one trachea, two bronchi one to right or left, then more branching into bronchioles bronchi (two bronchus) and trachea lined with cilia! and mucus both important for trying to keep pathogens and dirt out of the lungs! if think about it this whole system is pretty open to atmosphere, lot of crap can get down in there; mucus supposed to trap dirt dust and pathogens cilia beat and push the mucus and hopefully some trapped stuff up so can cough it out
smoking
antagonizes cilia, also hampers bodies ability to fight off of other pathogens smoking makes ppl vulnerable to other infections
airway structure 2
- Cartilaginous rings encircle and support trachea
- Trachea splits into two bronchi
- Bronchi branch into bronchioles within lungs
- Bronchioles terminate in alveoli (air sacs)
- Millions of alveoli in each lung
mucus and cilia elevator
muscus-cilia 2
- Trachea and bronchi are lined with ciliated respiratory epithelium
- Mucus secreted by respiratory epithelium
- Mucus traps particles and bacteria
- Mucus is beat upwards by cilia to throat (like an elevator)
- Mucus swallowed, digestive system deals with material
- Smoking → antagonizes cilia activity
Lungs
• Lungs are contained in the thoracic cavity • Covered by pleural membrane*** • Lungs are moist and stick to thoracic cavity via surface tension • Lung interior is filled with alveoli = air sacs
pulmonary surfactant
- Surfactant in lungs is critical for breathing
- Surfactant acts like a detergent and reduces surface tension of lungs and alveoli
- Without surfactant, alveolar surfaces can stick and collapse
- Premature babies lack enough surfactant → respiratory distress and failure
Alveoli 2
-Alveoli very very thin sacks at end of bronchioles Alveoli walls are one cell thick! they are hugged by the capillaries, which are also one cell thick** so this really really facilitates gas exchange–> think about connecting it to what we have said about the heart, blood comes over from heart, deoxygenated, comes over to capillaries right outside hugging surface of alveoli, so easy for oxygen to diffuse through to those capillaries and Co2 to diffuse other direction from capillaries to alveoli* goes back out nice and red very oxygenated, oxygen rich blood goes through pulmonary veins back to left side of the heart** their design maximizes surface area*** for gas exchange*
Alveoli 3
• Alveoli are extensively folded, increasing surface area • Alveoli are centers of gas exchange • Alveoli are one cell thick, capillaries surrounding them also one cell thick • Lots of macrophages (immune cells, professional eating cells do phagocytosis on pathogens, even with mucus and cilia lots of pathogens get into lungs want macrophages eat pathogens) in lungs (eat inhaled pathogens); carbon dioxide diffusing and oxygen diffusing passive through one part to the other, at this point air being breathed in air oxygen rich and blood is oxygen poor, so gradient for oxygen would be from alveoli to the capillaries that is the direction of passive movement** gradient for Co2 would be blood to alveoli* gradient in the right direction for O and CO2, so walls so thin can both go down gradient to alveoli
air sacs
• Lung interior is filled with alveoli = air sacs
pulmonary surfactant 2
walls of alveoli are very thin and fragile, without surfactant they would just pinch together and close** like this little wet sack that needs to be open* so could be very easy for walls of alveoli to stick to each other* like wet tissue paper sticking to itself, but surfactant is special substance coats inner lining of alveoli that prevents walls from sticking to themselves
fetuses and importance of surfactant
• Premature babies lack enough surfactant → respiratory distress and failure
-Fetuses do not start producing surfactant to a certain point, turns out to be the line in the sand when babies can survive outside of the womb– conversations about viability
-Fetuses produce surfactant around 23 weeks of gestation, meaning it is with current technology basically impossible to keep a fetus alive outside of the womb before 23 weeks, because if no substance that keeps alveoli open, millions of tiny tiny alveoli have to be open to get oxygen can get closed no way to shove oxygen down there, huge advances in neonatal care improving outcomes for infants born at 25 weeks of gestation* NO WAY TO OXYGENATE A FETUS WHO DOESN’T HAVE SURFACTANT* great area of science advancement to transfer oxygen to early babies
mechanisms of breathing 1
- Ventilation = breathing
- Inspiration = air intake = inhalation
- Expiration = air outflow = exhalation
- Diaphragm is muscle floor of thoracic cavity
Inspiration =
• Inspiration = air intake = inhalation
ventilation=
breathing
how mammals breathe negative pressure gradient
diaphram moves down, contracts, and upper arrows in image show rib cage moving up and out- where gas laws come in handy go down, rib cages go up and out creates more volume in thoracic cavity and also in lungs themselves, which sucks air and creates a pressure gradient for air* GREATER VOLUME IN LUNGS MEANS FOR A SECOND PRESSURE DROPS so gradient for air to go down into the lungs from atmosphere= passive process, what negative pressure breathing means we create pressure within lungs a bit negative relative to the atmosphere and air moves down that pressure gradient down into the lungs
if stabbed in chest…. pressure gradient 3
stabilize ppl but leave the knife in person’s chest until get to hospital otherwise at risk for lung collapse = caused by loss of pressure gradient*** even when not breathing, air outside of lungs has to be a bit lower than atmospheric pressure, negative pressure outside of them pressure inside body right outside of alveoli is already a little bit lower than atmospheric pressure, so when diaphragm goes down and ribcage goes up and out, then pressure gets even lower/negative so air drawn down to pressure gradient **and gets lower inside of the lungs, and air comes down from atmosphere** little space around alveoli to keep lungs inflated because pneumothorax stabbed in chest and if air from outside of space rushes in theory right outside of lungs can collapse if have atmospheric pressure right outside of the lungs, the lungs will not stay inflated*
inc pressure right outside of lungs, dec volume
pressure gradient 2
slightly lower pressure inside lungs vs outside of lungs in alveoli before you take a breathe to keep lungs inflated
pressure gradient 4 when air is finally exhaled
when we exhale diaphragm relaxes so that means it moves up again and rib cage goes back to its normal position passive process pushes air back out of the lungs, air is then exhaled
breathing is involuntary
most of the time we do not think about it, it is involuntary but we can cause muscles to breathe
tidal volume
volume of normal breath without any extra exertion of energy called title volume, normal breathe in and out
total lung capacity includes mroe than that, if took deepest breathe as you could and exhaled as har dasyou could bigger volume of air out, then residual capacity which is hte part of air not exchangd with breathe, so total lung capacity is literally everything so it is greater than lung volume*
total lung capacity does not equal tidal volume, it is greater than it! probably considerably greater*
lung volume
- Tidal volume = normal volume of a resting breath
- Vital capacity = maximum volume of air that can be voluntarily inhaled or exhaled, when breathe out as hard as you can then breathe in that is called vital capacity
- Volume of air cannot be exhaled = residual capacity, will always be some residual capacity, the volume of air not expelling from lungs
- TOTAL LUNG CAPACITY = VITAL CAPACITY + RESIDUAL CAPACITY
- Some air stays in respiratory tract (trachea, bronchi, nasal cavity) = dead space
vital capacity
= maximum volume of air that can be voluntarily inhaled or exhaled, when breathe out as hard as you can then breathe in that is called vital capacity
TOTAL LUNG CAPACITY =
• TOTAL LUNG CAPACITY = VITAL CAPACITY + RESIDUAL CAPACITY everything can draw in and out if inhale and exhale our hardest, plus whatever extra volume is down deep in ur lungs we are not exchanging on every breathe
Volume of air cannot be exhaled =
• Volume of air cannot be exhaled = residual capacity, will always be some residual capacity, the volume of air not expelling from lungs
dead space
volume of air stays in upper part of respiratory track
residual capacity has to do with lungs, but not wringing out trachea, there is some normal air left and that volume is called dead space, some lingers don’t breathe out ex. if tidal volume 500 mL, and dead space is 150 mL= then fresh air you are exchanging is only 350 mL per breathe
mechanism of breathing 2
- Contraction of diaphragm → thoracic floor descends, expands volume of thoracic cavity
- Expansion of volume decreases air pressure (negative pressure/vacuum) in lungs
- Air flows in to lungs
- Relaxation of diaphragm → thoracic floor ascends, decreases volume of thoracic cavity
- Reduction of volume increases air pressure in lungs
- Air is expelled from lungs
- Breathing is involuntary, but voluntary rib (intercostal) muscles can contribute
gas exchange in alveoli, capillaries and tissues
- O2 concentration is high in alveoli
- O2 diffuses from alveoli into capillaries and RBCs
- Higher partial pressure of O2 in alveoli → higher conc of O2 into blood (Henry’s Law) b/c O2 a gas, but in this context can think about pressure being proportional to concentration, high partial pressure of oxygen in blood means a lot of oxygen in blood** so thats what pressure means in this case it just how much oxygen is there
- CO2 concentration is high in capillaries
- CO2 diffuses from capillaries into alveoli
- O2 is released in tissues, CO2 transported from tissues
CO2 gas exchange in particular
CO2 concentration is high in capillaries
CO2 diffuses from capillaries into alveoli
O2 is released in tissues, CO2 transported from tissues
cooperativity=
once hemoglobin picks up one oxygen more favorable to pick up another and another
and why curve is S shaped
hemoglobin curve
- y axis O2 saturation of hemoglobin= how much oxygen is being held by hemoglobin
- when partial pressure of oxygen around 100 mm Hg, not surpising when blood circulating right outside of alveoli in lungs, also makes sense Y coordinate is really high, hemoglobinis VERY SATURATED WITH OXYGEN** when a lot of oxygen presnt, which explains as blood is circulating by lungs hemoglobin is really really picking up oxygen, getting picked up by hemoglobin inside red blood cells nad carried by hemoglobin*
- blood circulates then around body
partial pressure of oxygen when body at rest
- not doign any exercise, partial pressure in those environments in muscles, tissues much lower than lungs which makes sense at 40 mmHg
- when look where we are on red curve, y coordinate is quite a bit lower because hemoglobin doesnt hold as much oxygen, good becasue want oxygen to deliver it to tissues not hold onto it
- so hb letting go of oxygen, means oxygen can then diffuse over to muscle cells, brain cells etc
tissues during exercise graph
light blue arrow, y coordiante is much much lower over there, becuase releasing oxygen you want Hb to LET GO of oxygen when blood is in an oxygen poor environment* because you want hemoglobin to give oxygen to cells that need it*
so around partial pressure of oxygen when blood near lungs hb very saturated with oxygen picks up oxygen adn holds it,w hen blood circulates around and red blood cells in oxygen poor environment, hb delivers it which is key to the cells that need it
the curve literally represents how much o is held by hemoglobin, any oxygen held by hemoglobin has not yet been delivered to muscles, or other cells that need it so when blood circluating by mus;ces or you are exercising you donto want hemo holding onto oxygen you want it releasing oxygen so cells can have it, so want a low o2 saturation of hemoglobin when blood is circulating by muscles
y axis “O2 saturation of hemoglobin”
saturation literally means how much oxygen Hb is carrying
don’t want it holding oxygen want it letting go of oxygen and delviering it*