Regulation Of Respiration

Question 1

Hypoxia

Answer 1

PO2, arterial, firing rate, 100mm, 80mm, 60mm, oxy-Hb, more acidic, fall in H+, inhibit respi; increased venti, PCO2 falls, inhibit venti.
Overcome.
Depends on PaO2, not O2 content, ineffective during anemia and CO poisoning
Mech: inhibit K+ channel by: inc cAMP, inhibit mito NADPH (to reduce glutathione, ratio change), heme containing protein, bound to O2

Question 2

Hypercapnia

Answer 2

Linear relation, stimulate receptor by increase H+ content in cell, affects venti mainly by central chemoreceptors.
Mechanism: increase H+ content block K+ channel. Increase nerve traffic in 9th nerve.
Effect of hypoxia on CO2 response.

Question 3

Acidosis

Answer 3

Change in arterial pH. Acidosis inhibits acid extruding transporters like Na+-H+ exchanger. Increase H+ in cell, inhibit K+ channel. Poisons too, and blood pressure below 60 mm Hg. Aortic bodies.

Question 4

Peripheral chemoreceptors

Answer 4

Carotid, aortic. pH, Pao2, PCO2. To DRG. Carotid: chemosensitive, 2mm,2mg, bifur, high blood flow, high metabolic rate, type 1-glomus. Voltage, neuroectodermal, neurotransm. Type 2- sustentacular.
Aortic: asc aorta, arch of aorta. Vagal afferents. Less effective.

Question 5

No chemical control of respiration

Answer 5

Upper airways, lungs, fine tuning breathing and protect lungs. Chest wall mechanoreceptors too, and chemoreceptors.

Question 6

Slow adapting receptors

Answer 6

Smooth muscle of conducting airways, myelinated afferents, pulmonary stretch receptors.
Hering- Breuer reflex: inflation, deflation

Receptors r slowly adapting stretch receptors in lung parenchyma and airways, afferent and efferent pathways are vagus nerve

Question 7

Rapidly adapting receptors

Answer 7

Myelinated afferents, larger conducting airways.
Irritant receptors- allergy, inflammation, noxious stimuli.
Very sensitive to histamine, serotonin, bradykinin, prostaglandins.

Question 8

C fiber endings

Answer 8

Terminals of unmyelinated nerves.
Pulmonary C fibres: alveoli, acc from pulmonary capillary circulation. J fibres
Bronchial C fibres: airways, acc from bronchial circulation.
Pulmonary: lung injury, inflation, congestion.
Bronchial: chemical
Cause shallow breathing, bronchconstricyion, airway secretion

Question 9

Yawning

Answer 9

Removed excess CO2 from blood and activates body 
Heralds sleep
Improves lung expansion
Improves venous return
Nonverbal communication