Traffic - Week 13 Flashcards
pulmonary ventilation (simple)
breathing
external respiration
gas exchange between the blood and alveoli (air sacs)
gas transport (car)
blood transports gases to tissues (CV system)
internal respiration
gas exchange between the blood and tissues (CV/tissues)
cellular respiration
use of O2 to produce ATP (cells)
functions of respiratory
obtain O2, eliminate CO2
nonrespiratory functions (traffic police - door)
- route for water and heat loss
- enhance venous return
- acid-base balance (CO2)
- vocalization
- defense against inhaled
invaders - sense of smell
- alters blood composition
airways - smallest bronchioles (smooth)
have no cartilage; smooth muscle regulates air flow (broncho constriction and broncho dilation)
alveoli (air sacs) (alvin-doorway)
- thin walled and surrounded by capillaries
a. large surface area for gas exchange
b. type I cells - simple squamous epithelium c. type II cells - secrete surfactant
d. macrophages fight invaders
pleural sacs (lubricate - thor)
- each lung is separate
2. intrapleural fluid lubricates surfaces and helps lungs stick to thoracic wall
in ventilation air flows down a…
pressure gradient
atmospheric pressure (measurement)
atmospheric pressure (760 mmHg at sea level)
lungs will always expand to fill the thoracic cavity (cats couch)
intrapleural fluid (sticky)
b. transmural pressure gradient (difference in pressure in areas)
(1) intra-alveolar pressure always equilibrates with atmospheric pressure
(2) greater pressure outward than inward
inspiration (ops)
a. inspiratory muscles contract (diaphragm and external intercostals)
b. volume of thoracic cavity and lungs increases
c. intra-alveolar pressure decreases
d. air flows in
expiration (ops sleeping - piano)
a. inspiratory muscles relax (quiet breathing)
b. volume of thoracic cavity and lungs decreases c. intra-alveolar pressure increases
d. air flows out
forced expiration (body builder - fridge)
expiratory muscles contract (abdominal wall muscles and internal intercostals)
airway resistance adjusted to…
meet the body’s needs
matching airflow to blood flow (ventilation-perfusion coupling) (berkeley bowl)
local controls act on bronchiolar and arteriolar smooth muscle
simultaneous adjustments mean air and blood not wasted ex. - if blood flow > airflow (more__in blood)
brocho___
vaso___
if blood flow > airflow, increased CO2 and decreased O2 in alveoli, so broncho dilation and vasoconstriction
healthy lungs (recoil)
recoil after stretching and are compliant (easy to inflate)
2 main factors - lung elasticity
a. elastin fibers in lung connective tissue
b. alveolar surface tension
in healthy lungs breathing requires little energy (percentages)
a. 3% of total energy at rest
b. 5% during exercise
c. up to 30% at rest with obstructive lung
disease
gases diffuse down partial pressure gradients (slide)
pressure exerted by a particular gas in a mixture of gases or dissolved in a body fluid)
alveolar PO2 is lower than..
we naturally have more CO2 bc its produced in body.
atmospheric PO2.
and alveolar PCO2 is higher than atmospheric PCO2
a. water vapor in lungs dilutes gases
b. newly inspired air mixes with old air (15% new air with inspiration)
CO2 requires a smaller gradient for (sol)
efficient transfer because it is more soluble (usually about equal amounts of O2/CO2 exchanged)
at lungs PO2 is always higher in..
CO2 is higher in the..
alveoli, O2 is moving to the blood.
b. PCO2 always higher in blood (bc you made it), CO2 moves from blood into alveoli
at tissues, PO2 always higher in..
the blood, O2 is moving to the tissues.
b. PCO2 always higher in tissues (bc you made it), so CO2 moves into the blood
during exercise…(alvin, caps trenchcoat - bookshelf)
a. more pulmonary capillaries open, increasing surface area for exchanges
b. greater stretching of alveolar membranes increases surface area and thins membrane (decreased distance for diffusion)
disease thickens (EFP)
EFP
membrane and increases distance for diffusion (pulmonary edema, pulmonary fibrosis, pneumonia
O2 (% dissolved) (both)
- 1.5% dissolved in blood
- 98.5% on hemoglobin (Hb)
Hb + O2 ↔ HbO2 (reduced Hb) (oxyhemoglobin)
Hb (hemoglobin) saturation - primary influence is…
PO2
Hb-O2 dissociation curve (blood mountain - tv)
(1) plateau portion means that blood can carry nearly maximum amounts of O2 at varying PO2 levels (safety margin on low O2 environments)
(2) steep portion means that small decreases in PO2 at active tissues allow more O2 to be released
curve shifts to the right in active tissues (active - club parking lot)
(more O2 is released at active tissues at a given PO2) - just means that hemogloblin will release more O2 because:
(1) Bohr effect - increased PCO2
(2) increased acid (from increased CO2 and lactic acid)
(3) increased temperature
(4) increased 2,3-bisphosphoglycerate (BPG), produced inside RBCs in increasing amounts when HbO2 levels below normal
co2 (% dissolved in blood) (sle)
10% dissolved in blood
(how much CO2 is carried) - 30% as HbCO2 (carbaminohemoglobin) (co2) removal of O2 from HbO2 at tissues….
(take off O2, add CO2 - basically)
a. increases the affinity of Hb for CO2 (Haldane effect)
(how much CO2 is carried) - 60% as HCO3- (bicarbonate, more soluble than CO2) (ana hall)
a. CO2 +H2O↔H2CO3 ↔H+ +HCO3-
b. can occur in plasma, but more efficient in RBCs because of enzyme carbonic anhydrase
HCO3 out of RBC at tissue, in at lungs. (easier to carry in plasma - more space)
c. HCO3–Cl- carrier in RBC membrane
medullary respiratory center (controls breathing) (purple heart - kitchen door)
pattern probably established by pacemaker activity in rostral ventromedial medulla
dorsal respiratory group (DRG) responsible for (controls breathing)
for quiet breathing
a. inspiratory neurons terminate on motor neurons in spinal cord which supply inspiratory muscles
b. quiet expiration begins when neurons stop firing
ventral respiratory group (VRG)(controls breathing)…(loud heater - hallway)
important when demands for ventilation increase (exercise, etc)
a. not active in quiet breathing
b. stimulate motor neurons supplying expiratory muscles
pons respiratory centers (controls breathing) (tide pools)
- pneumotaxic and apneustic centers “fine tune” medullary centers to produce smooth inspirations and expirations
Hering-Breuer reflex (breathing control) (brow)
- pulmonary stretch receptors in airways are activated
at large tidal volumes
a. inhibit inspiratory neurons
influencing factors..(control of breathing) (chemo - couch)
- a. central chemoreceptors in medulla sense increased PCO2 (via increased H+ in CSF) and signal respiratory centers to increase ventilation
b. peripheral chemoreceptors known as carotid bodies and aortic bodies sense increased H+ and signal to increase ventilation
PO2 important only at (control of breathing) (chemo again)
very low O2 levels a. peripheral chemoreceptors signal to increase ventilation
precise triggers to increase ventilation are…
unknown (ventilation increases before significant changes in PCO2 and PO2)
triggers to increase ventilation (swiss - tv)
may be... a. proprioceptors in muscles and joints stimulating respiratory centers b. increase in body temperature c. epinephrine d. input from cerebral cortex
other factors to increase ventilation (pecs)
pecs
- reflexes like coughing/sneezing
- pain
- emotion
- swallowing
matching airflow to blood flow - bronchioles - increased CO2 =
AND
decreased CO2 =
if you have more waste (CO2 - you want to get rid of it - dilation). don’t want to remove all CO2, so constrict.
bronchioles
a. increased CO2 ➝ broncho dilation ➝ increased airflow
b. decreased CO2 ➝ broncho constriction ➝ decreased airflow
matching airflow to blood flow - arterioles - decreased O2 =
increased O2 =
(opposite in systemic artery- if tissue is low in O2, you vasodilate). in pulmonary, decreased O2 means there’s no point in sending blood there, so vasoconstrict.
a. decreased O2 ➝ vasoconstriction ➝ decreased blood flow
b. increased O2 ➝ vasodilation ➝ increased blood flow
lung elasticity - alveolar surface tension (alvin - bathtub)
water molecules lining alveoli attract each other, creating surface tension
surfactant decreases surface tension (without it lungs would collapse), increases compliance and reduces work needed to breathe. also enhance phagocytosis
simultaneous adjustments - airflow > blood flow (go get it)
broncho____
vaso___
if there is increased O2, you need to get it, so vasodilation.
if airflow > blood flow, decreased CO2 and increased O2 in alveoli, so broncho constriction and vasodilation.
airway resistance - parasympathetic stimulation (don’t need as much air). broncho____
broncho constriction ➝ increased resistance ➝ decreased airflow
airway resistance - sympathetic stimulation/epinephrine (need more air)
broncho dilation ➝ decreased resistance ➝ increased airflow
intra-alveolar a.k.a. intrapulmonary pressure..
varies
intrapleural pressure a.k.a. intrathoracic pressure is…(measurement)
within the pleural sac (756 mmHg at rest)
visceral layer
inner wall of pleural sac
parietal layer
outer layer of pleural sac
sticky in pleural sac
left to right
slippery in pleural sac
up and down
brochioles respond to
CO2 levels
arterioles respond to
O2 levels
P02 in atmosphere is about (mph)
160 mmHg
P02 in alveoli is about (perfect)
100 mmHg
PCO2 in lungs is about (think half)
40 mmHg
Co2 - 60% as HCO3- (bicarbonate, more soluble than CO2) -
HCO3 out of RBCs at tissue, in at…(window tissue)
in at lungs
Cl- into RBCs down electrical gradient at tissues, out at lungs (chloride shift)
d. most of the accumulated H+binds to Hb (helps buffer the blood)
hb saturation - pulmonary capillaries - increased 02 leads to formation of..
(hemoglobin wants to bind with oxygen in lungs in pulmonary)
HbO2 at lungs
hb saturation - systemic capillaries - decreased PO2 leads to…(letting go)
(hemoglobin wants to let go of oxygen at tissues bc they need it)
.. .O2 dissociation from HbO2 at tissues
partial pressure of oxygen in atmosphere is…(car in the atmosphere)
160 mm Hg
partial pressure of oxygen in alveoli…(perfect lungs)
100 mm Hg
CO2 partial pressure in lungs is about
40 mm Hg
partial pressure of CO2 in tissues is about..
46 mm Hg
primary influence on Hb is..
PO2 (oxygen saturation)
carbon dioxide makes body more…
acidic
in a healthy person, main factor controlling respiration is..
CO2
for systemic arterioles, decreased oxygen levels leads to..
vasodilation
for bronchioles, increased carbon dioxide levels lead to
bronchodilation
for pulmonary arterioles, decreased oxygen levels lead to
vasoconstriction
