Lecture 12 Flashcards
Dalton’s Law of Partial Pressures
total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas in the mixture
the partial pressure of each gas is directly proportional to its percentage in the mixture
Henry’s Law
-when a mixture of gases is in contact with a liquid, each gas will dissolve in the liquid in proportion to its partial pressure
-the amount of gas that will dissolve in a liquid also depends upon its solubility
Solubility and p. pressure of key gases in respiration
CO2 in respiration
Percentage of O2 saturation in various places in the body
Percentage of CO2 in various places in the body
the amount of gas reaching the alveoli
ventilation
the VENOUS blood flow reaching the alveoli
perfusion
in other words, the best perfusion ideally goes to the alveoli that have the best ventilation at any given moment
ventilation-perfusion coupling
if PCO2 in alveoli is high
dilate the bronchioles servicing those alveoli constrict the CO2 loaded blood vessels [arterioles]
if PCO2 in alveoli is low
constrict the bronchioles servicing those alveoli dilate the CO2 loaded blood vessels [arterioles]
In internal respiration, pressure and diffusion gradents are
reversed from external
PO2 in tissues is always _____ than the systemic arterial blood
Lower
BLANK carries oxygen in blood
hemoglobin
Each hemoglobin binds how many oxygen molecules?
4
the hemoglobin-oxygen combination is called
oxyhemoglobin
hemoglobin that has released oxygen is called
reduced or deoxyhemoglobin
when all four hemes of the molecule are bound to oxygen
saturated hemoglobin
when one to three hemes are bound to oxygen
partially saturated hemoglobin
Max saturation of O2 in blood
98%
How much O2 in blood?
20% by volume, 20ml per 100ml of blood.
How much O2 is released as blood flows thru capillaries?
5ml
How much oxugen is unloaded during one systemic circulation?
20-25%
Factors that increase O2 unload from Hb are higher in lungs or tissues?
Tissues
biproduct of RBC metabolism that helps unload Os from Hb
2,3-biphosphoglycerate
can 2,3BPG bind to HbF(etal)?
No
cells metabilizing glucose, ^ CO2 and H+, causing acidosis (v pH), weakening of Hb O2 bond
Bohr effect
Working tissues increase factors that make O2 offloading easier
yes
NO
N2O
Hb is a
vasoconstricter and NO scavenger
Deoxygenated Hb picks up
CO2 and NO and carries them to lungs for offloading
70% of CO2 is transported in the blood as
Bicarbonate (HCO3-)
reversibly catalyzes the conversion of carbon dioxide and water to carbonic acid in RBCs.
Carbonic anhydrase
at the tissues
to counterbalance the outrush of negative bicarbonate ions from the RBCs, chloride ions [Cl–] move from the plasma into the erythrocytes
Chloride shift
at the lungs
Chloride shift is reversed
bicarboniate binds with hydrogen to make carbonic acid, thats split by carbonic anhydrase into CO2 and water, and COs diffuses from blood into alveoli and exhaled.
the lower the PO2 and hemoglobin saturation with oxygen, the more carbon dioxide can be carried in the blood
Haldane effect
As more CO2 enter BL, more O2 dissociates from Hb
Bohr effect
The more O2 dissassociates from HB
more CO2 combines with Hb, more bicarbonate ions formed
relationship b/t tissue and pulmonary activity
reversed
Pacesetting respiratory center
DRG (dorsal respiratory group)
Continuously inhibits the inspiration center
pontine respiratory group
irritants promote reflexive ______ of air passages
constriction
stretch receptors in the lungs are stimulated by lung
inflation [prevent over-inflation]
inflation reflex [Hering-Breuer]
example: breath holding that occurs in anger
hypothalamic controls act through the limbic system to modify rate and depth of respiration
examples: voluntary breath holding, taking a deep breath
cortical controls are direct signals from the cerebral motor cortex that bypass medullary controls
carbon dioxide in the blood diffuses into the
cerebrospinal fluid where it is hydrated
rise in CO2 is called
hypercapnia
control of breathing at rest is regulated by the
hydrogen ion concentration in the brain
slow and shallow breathing due to abnormally low PCO2
levels
hypocapnia
breathing cessation
apnea
arterial oxygen levels are monitored by the
aortic and carotid bodies
if carbon dioxide is not removed [e.g., as in emphysema and chronic bronchitis]
chemoreceptors become unresponsive to PCO2 chemical stimuli
even if carbon dioxide and oxygen levels are normal
changes in arterial pH can modify respiratory rate
Nerve involved in peripheral chemoreception
CN IX, pharyngeal branch of glossopharyngeal nerve
During vigorous excercise, what changes
breathing becomes deeper and more vigorous, but RATE doesnt change as much as you might think
COPD
Chropnic Obstructive Pulmonary Disease
Two examples of COPD
chronic bronchitis, obstructive emphysema
Blue Bloater
chronic bronchitis
a persistent cough that produces sputum
for at least three months in two consecutive years
chronic bronchitis, decrease in O2, increase in CO2
chronic bronchitis caused by
chronic irritation of inhaled substances and microbial infections
Pink Puffer
emphysema
loss of elasticity of the lung tissue; destruction of structures supporting the alveoli; and destruction of capillaries feeding the alveoli
emphysema
who gets mysterious clubbing of fingertips?
pink puffers
characterized by dyspnea, wheezing, and chest tightness active inflammation of the airways precedes bronchospasms
[bronchoconstriction]
Asthma
episodic reversible bronchoconstriction
bronchial asthma
infectious disease caused by the bacterium Mycobacterium tuberculosis
tuberculosis
Recieve
Tx for TB
6-12 months of antibiotics
historical names of TB
white plague, consumption
What percent ofallpatientswithlungcancerweresmokers
90%
Lung cancer accounts for how many of cancer deaths in US
1/3
[20-40% of cases] arises in bronchial epithelium
squamous cell carcinoma
[25-35% of cases] originates in peripheral lung area
adenocarcinoma
[20-25% of cases] contains lymphocyte-like cells that originate in the primary bronchi and subsequently metastasize
small cell carcinoma
Review the laws!
