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106 Cards in this Set

  • Front
  • Back

Functions of the respiratory system

1) Gas exchange


2) Acid-base balance: pH 7.4


3) Communication: sound and smell


4) Metabolism of endogenous and exogenous substances; Ex) angiotensin converting enzyme


5) Thermoregulation


6) Immune Function

Vocabulary


Eupnea


Dyspnea


hyperpnea


polypnea


apnea


tachypnea


bradypnea

normal breathing


difficulty breathing


increased depth and frequency of breathing


rapid, shallow breathing


stopped breathing


increase in respirotory rate


decrease in respiratory rate

3 steps of Gas Exchange

Step 1) ventilation = inhalation and exhalation of air


2) External respiration = pulmonary gas exchange, O2 diffusion into pulmonary capillaries, CO2 diffusion in to alveoli


3) Internal Respiration = systemic tissue gas exchange = deliver O2 to support tissue metabolism and eliminate CO2 from tissues

Tidal Volume ?




Functional Residual Capacity ?

Volume of each breath




the air an animal lives off of during the pause btw breaths = ERV + RV



IVR = inspiratory reserve volume = ?




ERV = Expiratory reserve volume =?




RV = Residual Volume =?





Extra volume that can be inhaled after a normal inhalation




Extra volume that can be exhaled after a normal exhalation




Volume in the lungs after complete exhalation

Barometric pressure ___ with increasing altitude




at sea level =

decreases




760 mmHg

Gauge pressure = ?

pressure in alveoli - atmospheric pressure

Boyle's Law states that volume and pressure are ____ proportional




As volume ____ pressure ______

inversely proportional




increases; decreases

Transpulmonary pressure is the amount of pressure needed to keep ____ at its _____ volume without _____.




Atelectasis = ?

alveolus; smallest; collapsing




collapse of alveoli

Surfactants help to....



1) reduce collapse of alveoli


2) help with even distribution of alveoli ventilation


3) improvement in lung compliance

According to Poiseulle's Law, as radius ____ resistance ____



decreases


increases

Regulation of airway diameter:




parasympathetic system =




sympathetic =

constriction




dilation

Complete connective tissue septa


= each bronchiole is separate, so no gas exchange btw alveolar units


= helps keep infection from spreading

In the Cow and Pig

No ct septa


= air can move from alveoli to alveoli


= collateral ventilation


= infection can spread to whole lobe

In the dog, cat, and primate

Partial ct septa


= some collateral ventilation


= infection spreads more slowly

Horse and Sheep

vasodilators

Nitric Oxide


sildenafil


PGI2


beta-AR


MR

vasoconstrictors

ETA


ETB


alpha-AR


PDE5

Alveolar hypoxia = potent vasoconstrictor


generalized lung hypoxia = generalized vasoconstriction = ?

pulmonary hypertension



Brisket Disease

cattle at high altitude = lower at. pressure = more difficult ventilation and poor perfusion due to less O2


= Right heart failure and edema in the brisket

EIPH = exercise induced pulmonary hemorrhage

CO Increases during exercise


pulmonary vascular resistance decreases = vessels dilate


pulmonary artery pressure Increases = cause rupture of the thin capillaries around alveoli

Respiratory Airways:




conducting portion =

NO gas exchange


nasal cavity, nasopharynx, larynx, trachea, bronchus, bronchiole, terminal bronchiole

Respiratory Airways:




respiratory portion =

gas exchange area


respiratory bronchiole, alveolar duct, sac, and millions of alveoli

Fxns of airways:

1) brings appropriate amount of cleansed and conditioned air into close contact w/ capillaries, so Gas Exchange of O2 & CO2 by passive diffusion can occur efficiently


2) Olfaction


3) sound production

Nasal Cavity 3 regions = ? and their epithelium





1) cutaneous = stratified squamous keratinized to non-keratinized




2) Respiratory = ciliated pseudostratified columnar




Olfactory = ciliated pseudostratified columnar

Respiratory region of nasal cavity = ciliated pseudostratified columnar



Fxns:

humidifies inhaled air


traps particulates and microbes and cilia move mucous (= produced by goblet cells) material in one direction where it can be swallowed





olfactory epithelium

olfactory cells


sustentacular cells


basal cells


ciliated pseudostratified epithelium

epithelium of epiglottis and vocal folds of larynx

non-keratinized stratified squamous


NO secretory glands

Trachea =

respiratory ep.: cilia, goblet cells, serous cells


Propria-submucosa = loose ct. = seromucous glands and elastic fibers


cartilage w/ adventitia around it = loose ct.


trachialis m.



Bronchi =

Resp. ep. = fewer seromucous glands and thinner


Smooth m.


cartilage



Bronchioles & term. bronchioles

ciliated simple columnar


ciliated cuboidal


clara cells


No Cartilage


No glands



Alveolus is a sphere made of _____

pneumocytes



Type I pneumocytes

gas exchange


simple squamous

Type II pneumocytes

secrete surfactant = decreases surface tension


cuboidal epithelium

Blood-gas barrier

1) endothelium


2) basement membranes/basal laminae


3) type I pneumocytes

Ficks Law




Daltons law






Henry's Law



defines optimal diffusion




defines partial pressure




MW and solubility used to determine concentration of gas in a liquid

Application of Henry's law


Hyperbaric oxygenation therapy




How does it work?




What can it treat?



pressure raised = tissues absorb more O2 and more O2 dissolves in the blood




anaerobic bacterial infections




heart disorders, CO poisoning, cerebral edema, bone infections, gas emboli, crush injuries



gases move from _____ to ____ pressure

HIGH to LOW

Hypoventilation = ______ in PA O2


and _______ in PA CO2




Hyperventilation = ______ in PA O2


and _______ in PA CO2





Decrease and Increase




Increase and Decrease

Ideal Lung function:


PA O2 ____ Pa O2

= equal to

______ ______ is best for evaluating lung function

Arterial Blood

Compare PO2 and PCO2 in alveolar gas, arterial blood, and venous blood....lowest to highest



PO2: Venous; Arterial; Alveolar = Highest




PCO2: Alveolar = Arterial; Venous = Highest

Define perfusion

perfusion is adequate blood flow to tissues

What effect does perfusion rate have on PA O2 and Pa O2?





decrease/ rest = Pa O2 and PA O2 = 100




increase/ exercise = Pa O2 and PA O2 = decrease b/c more mixed blood in the capillaries due to the more rapid blood flow

What does the ventilation/perfusion ratio determine?




What does a low ratio mean?




a high ratio?

the adequacy of pulmonary gas exchange by quantifying the amount of alveolar ventilation in relation to pulmonary capillary flow




= ventilation blocked; PCO2 = higher; PO2 = lower




= perfusion is blocked; PCO2 = lower; PO2 = higher

What does PO2 determine?

the quantity of dissolved oxygen in the plasma


the higher the partial pressure, the more O2 will be dissolved in plasma

Saturation of Hb =

describes the % oxygen binding sites on Hb occupied by oxygen

How do we determine the saturation of Hb?


Name 3 points on the oxygen-hemoglobin curve....




If PaO2 = 100 mmHg, then %Hb =


If Pa O2 < 60 mmHg

using the oxygen-hemoglobin dissociation curve


30-60


40-75


60-90




100 %


%Hb saturation < 90% and the animal will need supplemental O2

What are the reasons for RIGHT Oxygen-Hemoglobin Dissociation Curve Shifts (= Hb releases O2 more readily)?

Increases in:


2,3 BPG


[H+] (= Low pH)


CO2


Temperature

What are the reasons for LEFT Oxygen-Hemoglobin Dissociation Curve Shifts (= Hb releases O2 LESS readily)?

Decreases in:


2,3 BPG


[H+] (= High pH)


CO2


Temperature



The Bohr effect

In an acid environment (low pH), O2 splits more readily from hemoglobin, and hemoglobin is thus less saturated with O2

What is the concentration of Hb in g/dl in...


normal?


anemia?


polycythemia?

15


10


20

Why should any vertebrate care about carbon monoxide poisoning?
CO binds 200x more effectively to Hb than O2
What effect does CO poisoning have on [Hb] when 50% of Hb is bound to CO?
The curve shifts down when compared with the normal [hb] curve decreasing the total oxygen content. A decrease in PaO2 also occurs with decreasing [Hb] levels. Thus, O2 will have a difficult time binding to Hb at such a low PaO2.
Total Oxygen Content =
The amount of O2bound to hemoglobin (Hb) + The dissolved O2 due to the PaO2

Haldane effect

relates to the shift in CO2 content curve with changes in PO2


beneficial for picking up more CO2 when it's in the tissues

Hypoxemia

less than normal arterial oxygen partial pressure = < 60 mmHg


Normal = 80-100 mmHg

Five causes of Hypoxemia

1) Hypoventilation


2) Low PlO2


3) V/Q Mismatch


4) Right to Left Shunt


5) Diffusion Limitation

What is the significance of a normal V/Q ratio?

The amount of alveolar ventilation in relation to pulmonary capillary blood flow determines the adequacy of gas exchange.

Normal V/Q = 0.8



The most common cause of hypoxemia in diseased states

Low V/Q Mismatches = low to no ventilation

True or False




Regions w/ V/Q > 1.0 do NOT contribute to hypoxemia

True

True or False




Shunts are responsive to increasing Fi O2/ Oxygen therapy

False

What are the possible causes of hypoxemia if there's an A-a O2 difference?




How else could you narrow down these possible causes?

Diffusion impairment


Low V/Q


Shunt




Response to Oxygen therapy, Shunt is unresponsive to O2 therapy

What are the possible causes of hypoxemia if there's NO A-a O2 difference?

hypoventilation


high altitude/ low PiO2

Control of ventilation




a) in the pons?




b) in the medulla oblongata?

= more of the fine tuning of breathing




= neurons that generate regular bursts of activity to initiate breathing = btw medulla and spinal cord

How is breathing regulated?

1) Receptors (sensors) that gather info. and send it via the afferents to the brainstem




2) Controller = brainstem coordinates the info. and sends impulses via efferents to the effectors




3) Effectors (respiratory muscles) adjust ventilation and Decrease PaCO2, which decreases the sensor input

Name the function of the breathing reflexes of the nose, pharynx, and larynx

Sneeze reflex: remove particulates/irritant


Dive reflex: prevent H2O from entering lungs


aspiration/sniff: clear the nose of mucous and obstructions


swallowing: coordinated muscle contractions to propel into esophagus


mechanoreceptors = detect changes in pressure and temperature


irritant receptors = couch and apnea in response to irritant to clear airway


water sensitive receptors = close larynx and prevent water getting into lungs

explain the function of...


1) slow adapting receptors




2) rapid adapting receptors

1) are in the lung and respond to stretching of airways sending an impulse in vagus n. to prevent over expansion of the lungs by monitoring lung volume




2) mechanoreceptors in the airway epithelium = cause cough, bronchoconstriction, mucus secretion, & rapid shallow breathing

What are C fibers?




Where are they?

non-myelinated axons = pain receptors = respond to mechanical, thermal, chemical changes


1) pulmonary interstitium = monitor distension of interstitium


2) walls of airways = stimulated by allergic or infectious diseases = causes tachypnea


3) respiratory muscles = control of muscle contraction strength

What is the significance of the Hering-Breuer Inflation Reflex?


Deflation reflex?

*Inflation and deflation reflexes that help regulate the rhythmic ventilation of the lungs. This prevents over-stretching or extreme deflation of the lungs.

*The Hering-Breuer Inflation reflex prevents damage from over stretching the lung by inhibiting inspiration and stimulating expiration


* The deflation reflex prevents over deflation by inhibiting expiration and stimulates inspiration



Thermoregulation response to


heat stress




cold stress

small tidal volume, tachypnea, vascular engorgement of respiratory and oral mucosa




large tidal volume, bradypnea

Name the peripheral chemoreceptors?




What do they do?

carotid bodies: at the bifurcation of the carotid a.


aortic bodies: above and below aortic arch




respond to changes in PaO2, PaCO2, and pH


decrease in pH or PaO2, increase in CO2 & H+ = increase ventilation




increase in pH, decrease in CO2 & H+ = decreases ventilation





Where is the central chemoreceptor?




What does it do?



It's in the retrotrapezoid nucleus of the brainstem, bathed in brain interstitial fluid




responds to changes in CO2 (enters via blood-brain barrier), H+, HCO3-, to increase or decrease ventilation





What blood gas parameters increase ventilation?

Increase PaCO2


Increase H+


Decrease PaO2

what is cyanosis?




SpO2?




CRT?

a bluish or purplish discoloration (due to deficient oxygen)




Saturation of Hemoglobin with oxygen




capillary refill time = time for color to return to an external capillary bed after pressure is applied to cause blanching = indicates perfusion


> 2 secs = poor perfusion

What is...


Complementary breathing?




biot breathing?




Kussmaul's breathing?




cheyne-stokes breathing?




apneustic breathing?

= sign; mechanism to reinflate alveoli




= group breathing




= uncontrolled, abnormal breathing, caused by metabolic acidosis, increase in tidal volume




= waxing and waning of breathing, Vt does up&down, poor feedback loop




prolonged inspiration inhibiting expiration; allows more gas exchange

Name some non-respiratory functions of the lung

thermoregulation


filter the blood


metabolism: angiotensin converting enzyme


Defense: ciliary escalator, macrophages


acid-base balance

What is Starling’s Law of the Capillaries?


Where does the rest of the fluid get absorbed?

= the filtered fluid produced by pulmonary capillaries (arterial side) is almost as much as the volume of fluid reabsorbed by the pulmonary capillaries (venous side)




stays in the interstitium or goes to the lymphatics

What is the difference between pleural effusion and pulmonary edema?
Pulmonary edema = excess fluid inside lungs; Clinically pink, frothy fluid coming from nose and treat with diuretic.

Pleural effusion = excess fluid btw visceral and parietal pleura; treat with thoracentesis

What pressure promotes filtration? Filtration occurs at the arterial or venous end of capillary?
Fluid production = Fluid filtration: High to low pressure (mm Hg) due to high hydrostatic pressure in the capillary and low hydrostatic pressure in the interstitium.

arterial

What pressure promotesreabsorption? Reabsorption occurs at the arterial or venous end of capillary?
Fluid removal = Fluid reabsorption: Low to high pressure (mm Hg) due to low oncotic pressure in interstitium and high oncotic pressure in the pulmonary capillary. The pulmonary and lymphatic capillaries will eventually reabsorb the excess pleural fluid.

venous

How does fetal circulation occur?

1. The uteroplacental circulation starts with the maternal blood flow into the intervillous space through decidual spiral arteries. Exchange of oxygen and nutrients take place as the maternal blood flows around terminal villi in the intervillous space.

2. The in-flowing maternal arterial blood pushes deoxygenated blood into the endometrial and then uterine veins back to the maternal circulation.


3. The fetal-placental circulation allows the umbilical arteries to carry deoxygenated and nutrient-depleted fetal blood from the fetus to the villous core fetal vessels. After the exchange of oxygen and nutrients, the umbilical vein carries fresh oxygenated and nutrient-rich blood circulating back to the fetal systemic circulation.

Describe the three types of shunts
1. Ductus arteriosus • Connects pulmonary artery and aorta; Blood flows from Rt to Lt in fetus • Bypasses the lungs • Allows developing heart and brain to get HIGHER PO2

2. Foramen Ovale• Opening btw the atria• One way Rt to Lt shunt, due to thin flap on the left side


3. Ductus Venosus• Bypass of the fetal liver• Connects umbilical vein to caudal vena cave•

The fetus exists in a state of hypoxemia. How can the fetus grow and survive with such a low PO2?
Hemoglobin has a higher affinity for oxygen and a low 2,3 BPG in their RBCs, meaning fetal Hb has a higher percent saturation, and the fetus has a higher Cardiac Output.

Acid Base balance

relatively constant [H+] due to regulation

What is pH?

-log10 of [H+]

what is an acid?




base?




buffer?

donates [H+]/proton to a solution




accepts [H+]/proton from a solution




a mixture of a weak acid and its conjugate base

Is water an acid or base?

it's amphiprotic and can function as both acids and bases

What is the relationship between pH and [H+]?

they're inversely and exponentially proportional to each other

What is a normal pH?


acidemia?


alkalemia?

7.35-7.45


7.35


7.45

acidosis =




acidemia =

all of the physical processes & chemical reactions that result in an abnormally pH




low blood pH; can Not have acidemia w/o acidosis



What are some causes and symptoms of acidosis?

causes: ethylene glycol (antifreeze); Aspirin; chronic kidney disease; hypoventilation




symptoms: depression, rapid & deep breathing, diarrhea, confusion, fever

What are some causes and symptoms of alkalosis?

causes: vomiting, increased loss of H+, hypoalbuminemia, kidney retention of HCO3-




symptoms: weakness, irregular heart beats, muscle twitching, dehydration, seizures

What factors affect pH?

PCO2


Strong Ion Difference: difference btw the sums of concentrations of the strong cations and anions


Weak Acid Buffer (Atot = total weak non-volatile acid)

Increase in Atot = ______H+ = _____




Decrease in Atot = _____H+ = _____





Increase = Metabolic Acidosis




Decrease = Metabolic Alkalosis

Increase in SID = _____




Decrease in SID = _____




Normal SID = _____


alkalinizing




acidifying




0







What is the Henderson-Haselbach equation?

pH = pK + Log (Base/Acid)

What do buffers do?




bicarbonate buffer?




phosphate buffer?



exchange a strong acid or base for a weak one


= results in less of an increase in [H+] due to incomplete dissociation




CO2 & HCO3- can be independently regulated




Major intracellular buffer pKa 6.8 = near normal





Acid-base imbalance




what is the 1st line of defense?


2nd line of defense?

1) Chemical buffers = bicarbonate, protein, & phosphate buffer system = instant response




2) Physiological buffers = lungs excreting CO2 = takes mins to hrs


= kidneys excreting H+ = hrs to days

What is..


Metabolic acidosis?


Respiratory acidosis?




metabolic alkalosis?


respiratory alkalosis?

HCO3- < 24 mM -> respiratory compensation (decrease PCO2)


PCO2 > 40 mmHg -> renal compensation (H+ excretion & increase in HCO3-)




[HCO3-] > 24 mM -> respiratory compensation (increase PCO2)


PCO2 < 40 mmHg -> renal compensation (decrease in HCO3-)



Birds have longer and wider trachea , so do they have more airway resistance than mammals?

No, due to the increase in both length and width

Do birds have a higher Vt?




Do they spend more energy overall?

Yes, 1.7 x higher




No, they spend less energy due to a greater compliance of the respiratory system

In birds, gas exchange occurs at the ______, which are ____ in contact with fresh air.




Gas exchange involves ______ air flow and it's ______ efficient than in mammals.

parabronchi


always




cross-current


more

In birds, the blood gas barrier is 60% thinner compared to mammals.


How does this help with gas exchange?

According to Fick's Law, the rate of diffusion will increase with an increase in cross sectional area and/or a decrease in the distance of the diffusion path.

Name some other reasons bird respiration is different from mammalian?




And how might it be a disadvantage?

unidirectional air flow


air sacs expand, but lungs are rigid


They have 2 types of hemoglobin (Hb A & D)




increased incidences of infection and apnea is more dangerous due to the almost lack of residual volume

What happens during the mammalian diving reflex?




And how do diving mammals deal with N2?

1) bradycardia


2) peripheral vasoconstriction


3) blood shift to lungs


4) switch to anaerobic metabolism


* they also have increased hematocrit values and large spleen = more blood reserve


*elastic aorta to keep blood pressure high




dive = collapse lung, so air, inc. N2, is in dead space = no gas exchange







What type of flow is gas exchange in the gills of fish?

counter current