respiration course pack part 2 (slide 55-100)

Question 1

What is Henry’s law?
What is the O2 consumption per min?

Answer 1

-Henry’s law is the amount of dissolved gas carried by blood is directly proportional to the partial pressure of the gas
-O2 consumption per min is 300ml O2/min

Question 2

What is essential for O2 transport?
How much O2 is bound to Hb?

Answer 2

Hemoglobin is essential for O2 transport since it allows blood to take up 65x more O2 than plasma, and it combines rapidly and reversibly with O2
-19.5% of O2 in blood is bound to Hb

Question 3

What contributes to Po2

Answer 3

-only O2 in plasma contributes to PO2

Question 4

What is the O2 dissociation curve shape?
What is Hb at high and low PO2

Answer 4

-sigmodal curve shape
-at high PO2 Hb is saturated (curve is more flat)
-at low PO2, Hb is deasturated to let O2 go to be available for working tissue of cell metabolism

Question 5

What is the percent change of HbO2 at low vs high PO2?

Answer 5

-at high PO2 the chnage from 100 to 80mmhg only results in 3% HbO2 change
-at low PO2 change from 40 to 20 mmhg is 40% change

Question 6

What does myoglobin bind to, where is it found?
What is the shape of the curve, when will it release O2?

Answer 6

-myoglobin only binds 1 O2 molecule, and it is found in skeletal muscle
-the curve shape is hyperbolic, and will only release an O2 at very low PO2

Question 7

What is the norml amount of Hb in the blood?

Answer 7

14g/100L is the normal amount

Question 8

What is the Bohr effect, and what happens during exercise in this process?

Answer 8

-Bohr effect is the shift of the HbO2 curve to the right when blood CO2 or temp increase, or pH decreases
-when we excercise we increase CO2 and acid production and produce heat, shifting the curve to the right, meaning when we drop PO2, and extra mount of O2 is released to be used in tissue
-makes O2 available sooner

Question 9

What does carbon monoxide do, how does it affect the HbO2 curve?
What happens to PaO2?

Answer 9

-CO has a high O2 binding site affinity and will reduce the amount of O2 in Hb, it also shifts the HbO2 to the left decreasing amount of unloading O2 in the tissue
-in CO poisoning PaO2 remains normal so you dont know that you do not have enough O2

Question 10

How is CO2 carried in the blood, 3 ways that it is carried?

Answer 10

1. physically dissolved in the blood (10%)-CO2 from tissues diffuses into the plasma
2. combined with Hb to form HbCO2 (11%)-CO2 combines with globin portion
3. as bicarbonate (79%)-CO2 combines with H2O to produce carbonic acid, diffuses into erythrocytes with help of carbonic anhydrase then ionizes into bicarbonate (Cl- comes into cell to maintain pH)

Question 11

What happens in lowering of PCO2?
What happens when PCO2 is higher in blood than alveoli?

Answer 11

-results in HCO3- getting transformed in to H2CO3 and further int o CO2, H2O, and HbCO2 making Hb+CO2
-there is anet diffusion from blood into alveoli which lowers the blood PCO2

Question 12

What is the haldane effect?

Answer 12

-it is the fact that mixed venous blood can carry more CO2 than can arterial blood, creating more H2CO3 and thus more bicarbonate for CO2 to be in

Question 13

What is the relationship between CO2 and PCO2 in the graph?
What happens if we double alveolar ventilation?

Answer 13

-it is a linear relationship
For example, if we hypoventilate and alveolar PCO2 rises, then arterial, capillary, tissue and venous CO2 also rises
-it halves alveolar PCO2, so an increase in alveolar ventilation proportionally increase CO2 removal

Question 14

What are the reasons that can lead to respiratory failure?

Answer 14

due to failure of:
1. the gas exchanging capabilities of the lungs
2. the neural control of ventilation (the drive to breath)
3.the nueromuscular breathing apparatus (respiratory muscles and their innnervation)

Question 15

what is hypoxia?

Answer 15

It refers to deficient blood oxygen, meaning PaO2 and Hb saturation are low

Question 16

What are the 5 causes that can lead to hypoxia?

Answer 16

1. inhalation of low PO2 (high altitude)
   2.hypoventilation
2. ventilation/perfusion imbalance
   4.shunts of blood across lungs
   5.O2 diffusion impairment

Question 17

1. what is hypoventilation caused by?
   2.What is ventilation/perfuion imbalance caused by

Answer 17

2.hypoventilation- alveolar ventilation in relation to CO2 production is reduced (PaO2 decrease and PaCO2 increases)
3. ventilation/perfusion imbalance-amount of fresh gas reaching alveolar region is too low

Question 18

3. what is shunt of blood caused by across lung, what is an example
   4.how is O2 diffusion impairment caused?

Answer 18

4.shunts of blood across lungs-venous blood returns to systemic circulation, deoxygenated by bypassing gas exchange region of lung
example- foramen ovule since baby in utero gets O2 from blood of mother, so when it is born the flap connecting lleft+right heart should close, if it doesnt its called shunt
5.O2 diffusion impairment-(thickening of alveolar capillary membrane)

Question 19

What is breathing controlled by, what is an example?
What controls gas exchange?

Answer 19

breathing is under voluntary (ex. hyperventilation), and involuntary control (ex. while asleep
-central nervous system controls gas exchange

Question 20

What controls voluntary and involuntary breathing?

Answer 20

-cerebral hemispheres control voluntary breathing
-brainstem controls involuntary breathing

Question 21

What parts of brainstem do involuntary control?
What are the 3 basic elements of respiratory control?

Answer 21

pons and medulla
1. sensors:gather info about lung volume and O2+CO2 content
2.controllers-info is sent here from the sensors, in the pons and medulla via afferent neural fibers
3.effectors-neuronal impulses are generated and sent via spinal motornuerons to effectors

Question 22

What are examples of sensors, central controller, and effectors

Answer 22

sensor-chemoreceptors, lung and other receptors
centrol controller-pons. medulla, etc
effectors-respiratory muscle

Question 23

What groups of cells does the medulla have?q

Answer 23

-they have pacemaker cells, that are located in the ventral respiratory group (generate basic rythm), and dorsal respiratory group that receives several sensory inputs

Question 24

What groups of cells are in upper pons?
What do these cells do?

Answer 24

-cells located here are called pneumotaxic center that modify inspirtaoty activity of the centers of medulla
-cells turn off inspiration leading to smaller tidal volume, which increases breathing frequency

Question 25

What does cutting these pneumotaxic centers do?

Answer 25

-cutting pneumotaxic centers causes breathing to become deep and slow (same effect as cutting vagus nerve)

Question 26

What groups of cells are in lower pons? What do they send/promote?

Answer 26

-called the apneustic center -they send excitatory impulses to the respiratory groups of the medulla, promoting inspiration

Question 27

What does removing the upper pons and the vagus nerve cause?

Answer 27

-causes apneuses which is tonnic inspiratory activity interupted by short expirations (dont have upper pons to tell you to stop breathing in)

Question 28

1.What happens when you turn off inspiration and have vagi intact vs cut? 2.What happens when you promote inspiration and have vagi intact vs cut, when there is a cut at the upper pons? 3. What happens to rhythm when you have vagi intact vs cut, when the lower pons is cut? 4. What happens when you cut at the medulla?

Answer 28

1.vagi intact- normal breathing pattern vagi cut-slow+deep breathing pattern 2.vagi intact-slower + deeper breathing pattern vagi cut-apnosis, large tidal breath 3.vagi intact- random pattern rhytmicity, volume is random vagi cut-same as with vagi intact 4. with vagi intact and cut, there is no breathing

Question 29

What levels/things are detected by chemoreceptors? What changes when one of these is changed? What are the 2 types of chemoreceptors?

Answer 29

-PO2, PCO2, and pH in arterial blood are detected by chemoreceptors -if these pressures or pH are changed ventilationw will also change -central and peripheral

Question 30

Where are central chemorecptors located and what do they detect? What do they drive?

Answer 30

-located on the ventral surface of medulla, and they detect pH of the cerebrospinal fluid (CSF) -drives the breathing under normal conditions

Question 31

What stimulated chemoreceptors? What happens when they are stimulated?

Answer 31

-drop in pH -minute ventilation increases causing hyperventilation, which causes reduced PCO2 in blood, and inCSF

Question 32

WHat increases when pCO2 levels increase?

Answer 32

-minute ventilation, breathing freqeuncy, and tidal volume

Question 33

What are peripheral chemorecptors sensitve to? Where are they located? What part of the medulla are they project to?

Answer 33

-changed in PO2, but are also stimulated by increased PCO2 and decreased pH -carotid bodies, and in aortic bodies which are made up of blood vessles, supporting tissue, and nerve endings of the 9th nerve (gloosopharyngela nerve) and vagus nerve (X nerve) -the afferent fibers of these receptors project to the dorsal group of respiratory neurons in the medulla

Question 34

Where do carotid bodies send info vs aortic bodies

Answer 34

carotid bodies send info with 9th nerve aortic bodies send info via X nerve (vagus nerve)

Question 35

What are the 3 types of pulmonary vagal receptors in the lungs that respond to mechanical stimuli?

Answer 35

1. pulmonary stretch receptors 2.irritant receptors 3.juxta capillary or J recptors

Question 36

Where are pulmonary stretch receptors located? What are they innervated by, and what do they respond to?

Answer 36

-located in the smooth muscle of the trachea down to terminal bronchioles -they are innverated by large myelinated fibers -they respond to the lung being distended

Question 37

What is the main refelx effect of the stretch receptors? What does it do, and in what age is it most noticebale in

Answer 37

Hering-breuer inflation reflex- which is the decrease in respiratory frequency due to long expiratory time -most noticeable in infants and animals

Question 38

Where are irritant receptors located? What stimulates them? What is innervated by and what does the stimulation lead to?

Answer 38

-Located between airway epithelial cells in the trachea down to terminal bronchioles -they are stimulated by noxious gas, ciggarate smoke, histamine, cold air and dust -innverated by large myelinate fibers -stimulation leads to bronchoconstriction and hyperapnea (increased depth of breathing)

Question 39

Where are Juxta capillary receptors located? -what are they innervated by What are they stimulated by?

Answer 39

-in the alveolar walls close to the capillaries -innervated by non myelinated fibers and have short bursts of activity -stimulated by an increase in the pulmonary interstitial fluid, like what may occur in pulmonary congestion and edema

Question 40

What does JC receptor induce, what does it also play a role in?

Answer 40

-it causes rapid and shallow respiration, intense stimulation can cause apnea, and -plays a role in dyspnea (difficulty breathing) which is associated by left heart failure and lung edema or congestion

Question 41

100How does minute ventilation increase in untrained and trainde subjects? What does endurance training delay?

Answer 41

-increase linearly up to about 50-65% of VO2 max, then increases greater than VO2 -delays the ventilatory inflection point