Lung: Week1b Flashcards
Is the amount of dissolved O2 delivered to tissues adequate?
no.
What are the three types of hemoglobin?
F = fetal A = adult S = sickle
What do we call the oxygenated and deoxygenated states of Hg?
oxy = relaxed (R)
deoxy = tense (T)
What are the qualities of an exercising muscle, and in which direction does it shift the O2 dissociation curve?
Muscles are acidic, carbonic and hot. It shifts the curve to the right and increases unloading of O2.
In which direction does an increase in 2,3-diphosphoglycerate shift the O2 dissociation curve?
Right.
Where does 2,3-DPG come from?
It is made by RBCs
What are the 3 forms in which CO2 can be carried in the blood?
- dissolved
- bicarbonated
- in combination with proteins
Which is more soluble in blood, CO2 or O2?
CO2 is about 20x more soluble in the blood.
What helps drive the following reaction:
CO2 + H2O <> H2CO3
carbonic anhydrase
For the following reaction, which occurs inside the RBC, where do the ions go and how is electroneutrality maintained?
H2CO3 <> H+ + HCO3-
- HCO3- leaves the RBC.
- H+ is stuck inside bc the membrane is impermeable to cations
- Cl- enters the RBC for electroneutrality (chloride shift)
How are carbamino groups formed?
The combination of CO2 with terminal amine groups on a protein. Most common is as follows:
HbNH2 + CO2 <> HbNHCOOH
How is O2 affinity of Hg affected by an increased in CO2, increase in temperature, increase in H+ and increase in 2,3-DPG?
All of these decrease the affinity of O2 to Hg and shift the curve to the right. This makes sense bc you want to be able to unload your O2 to the tissues that are in need.
How does the CO2 dissociation curve compare to that of O2?
The CO2 curve is much steeper and more linear than the O2 dissociation curve.
What does this equation mean for the ratio of HCO3- and Pco2?
pH = pK + log(HCO3-/[0.03Pco2])
It means that the ratio of Pco2 and HCO3 is very important for maintaining pH balance in the human body.
In static breathing conditions, what is the relationship between the aveolar, intrapleural and rib cage pressures?
(P alv) - (P ip) = 0
(P rib cage) - (P ip) = 0
Does the apex require more or less transpulmonary pressure than the base of the lungs to keep from collapsing?
The apex requires more transpulmonary pressure than the base of the lungs to stay open. (This might have something to do with the radius.)
What is the equation for flow rate?
flow rate = (Patm - Palv)/R
What common farming object describes the action of the ribs?
The bucket handle!
Is the slope of compliance linear?
No. It varies with lung volume and becomes less compliant as the lungs reach either extreme.
How does the volume-pressure curve change for inspiration and expiration?
Inspiration- āsā shaped
Expiration- shaped like a sq. root graph, or lower case r
Tell me four things about the brainstem respiratory control centers: Medullary, Apneustic, Pneumotaxic.
a. located in medulla and pons
b. sets respiratory rhythm
c. receives input from chemoreceptors, lungs and cortex
d. major output is to diaphragm via C3-5
Tell me 2 things about the Medullary Center
a. affects inspiration (dorsal) and expiration (rostral)
b. can alter the breathing pattern
Tell me two things about the Apneustic Center.
a. located in the lower pons and influences inspiration
b. results in prolonged gasping inspiration (this can be a sign of brain stem injury.)
Tell me two things about the Pneumotaxic Center.
a. Inhibits respiration
b. influences inspiratory volume and, secondarily, respiratory rate.
How does the cerebral cortex affect breathing?
a. plays major role in breath regulation
b. allows for on-demand changes to breath: singing, exercise
c. it allows for hyper and hypoventilation, within a certain range
How does the hypothalamus and limbic system affect breathing?
These regions affect your breathing in response to emotion.
How to the chemical sensors in the medulla work to regulate breathing?
CO2 is highly permeable to the blood brain barrier, so it can easily enter and relay messages to the medulla. This is the mechanism of our quickest response to changes in breathing.
Where are the carotid bodies and at which point in Po2 do they really kick in?
They are located at the bifurcation of the carotid arteries. When Po2 gets below 60mmHg they kick in. This low saturation is the only time when the O2 levels are what drive our respiration.
How do the pulmonary stretch receptors work?
They respond to stretch and can slow respiration by increasing expiration time. Hering-Breuer reflex prevents over inflation of the lungs.
How do irritant receptors affect breathing?
They react quickly and bronchoconstrict to limit exposure of lungs to toxic elements. They can be stimulated by cold air, noxious gases, cigarette smoke, etc.
What are J Receptors?
Stimulated by engorge pulmonary capillaries and an increase in interstitial fluid, these receptors may contribute to tachypnea and dyspnea during L-sided heart failure.
How does breathing vary during stages 1/2 and 3/4 of sleep? How does breathing change during REM?
1/2: breathing is periodic
3/4: breathing is regular and rhythmic
REM: regular breathing with period of apneas
Why does the Sat. O2 for babies vary much more quickly than that for adults?
Babies have a much lower FRC and a much higher metabolism.
What is the main function of gastrin? Where is it released? What releases it?
Fxn: up H+ secretion
Site of release: antrum
Releaser: peptides, AAs, ACh, distention
What is the main function of CCK? Where is it released? What releases it?
Fxn: up panc enzymes and up gallbladder contractions. Down gastric emptying.
Site of release: duodenum, pylorus
Releaser: peptides, AAs, FAs
What is the main function of secretin? Where is it released? What releases it?
Fxn: up panc fluids, HCO3, biliary fluid
Site of release: Duodenum
Releaser: Acid
What is the main function of GIP? Where is it released? What releases it?
Fxn: up insulin release, down gastric emptying
Site of release: duodenum, jejunum
Releaser: AAs, FAs, Glucose
What inhibits gastrin secretion?
Somatostatin
