RESPIRATION 16 Flashcards
1) What modifies breathing?
2) What is the primary stimulus for changes in ventilation
3) Which other two factors play lesser roles?
1) Sensory inputs
2) CO2
3) Oxygen and plasma pH
Ventilatory response to CO2
Name the two factors measured?
Respiratory rate Tidal Volume ( mL)
What is Hypercapnia?
What is the normal level?
What is the high level?
Abnormal high level of CO in blood.
40mmHg
45mmHg
What is Hypocapnia?
What is the low level?
Abnormal low level of blood CO2
35mmHg
What mediates CO2 chemosensitivity?
Oxygen
Central CO2 chemoreceptors 1) Location
2) What does it monitor?
1) Medulla
2) H+ in cerebro-spinal fluid and arterial circulation
Peripheral chemoreceptors
1) Structures?
2) What does it monitor?
1) Carotid and aortic bodies
2) Arterial level of oxygen and CO2/H+
How CO2 Chemoreceptors work?
1) Proton-sensing G-protein coupled receptor 4 ( GPR4) in RTN
2) Sense extra-ceullar pH lower than 7
1) What are medullary raphe and what do they do?
2) Are they chemosensitive?
3) These neurons are?
1) Serotoninergic neurons
2) Yes
3) Closed to vessels and capillaries
In terms of respiratory chemosensitivity and sleep, What is breathing dependent on?
Metabolic (CO2 and O2) control in Non-REM sleep
Clinical focus: sleep apnea
1) What is sleep apnea?
2) List 4 different forms of apneas.
1) Cessation of airflow without respiratory effort
2) Chyne-Stoked breathing
Idiopathic central apnea
Naroctic or anaglesic -induced apnea
Hypoventilation syndrome (Ondine’s curse)
25-40% of patients with sleep apnea also have?
Heart failure
Clinical focus: Cheyne-Stokes breathing (periodic breathing)
1) Description
2) Causes (3)
1) Waxing and waning of breathing
2) Can be due of heart failure, low sensitivity to CO2 or damage to respiratory centers
Clinical focus: Congenital Central Hypoventilation Syndrome
1) Aka
2) What leads to respiratory arrest?
3) Marked by?
4) Cause
1) Ondine’ curse
2) Hypoventilation
3) Reduction of ventilatory and arousal responses to CO2
4) Mutation of Phox2B gene
What is Phox2B?
Where is the Phox2B protein found?
1) A gene coding for transcription factor in autonomic nervous system
2) At the level of the RTN
Treatments:
1) Patients do not respond to: Congenital Central Hypoventilation Syndrome
2) What is require adequate ventilation, at least during sleep.
3) What is used during the 1st years of life?
4) What is used later in life
1) Ventilatory stimulants
2) Mechanical ventilation
3) Positive-pressure ventilation (PPV)
4) Bi-level psotive airway pressure ventilation continous negative extrathoracic pressure ventilation and diaphragm pacing
1) How does Phox2B required for?
2) How does a Phox2b mutation affect it breathing?
1) Development of several neuron types in the central and peripheral nervous systems
2) Genetic elimination of the RTN severely abolishes CO2 sensitivity in constitutive
O2 Mediated CO2 chemosensitivity: What do the following levels indicate: 1) 37 mmHg 2) 47 mmHg 3) 110 mm Hg
1) Severe hypoxia
2) Mild Hypoxia
3) Normoxia
Oxygen chemosensitivity:
1) Hypercapnia
2) Normocapnia
3) Hypocania
1) 48.7 mm Hg
2) 43.7 mmHg
3) 35. 8 mmHg
What is Hyperoxia? What is the normal level? What is too high? What is hypoxia? Low level of O2
Abnormal high level of oxygen in blood = 100-110mmHg > 110 mmHg Abnormal low level of blood O2 < 50 mmHg
Central oxygen chemoreceptors ( List the three)
1) The locus coeruleus
2) The thalamus
2) The preBotzinger Complex
1) Which receptors play a lesser role in hypoxia?
2) What does the prebotzinger complex do?
1) Central oxygen chemoreceptors
2) The site generating respiratory rhythm
Cartoid bodies
1) Contain
2) Detect
3) Unique trait
1) Glomus cells
2) Detect low oxygen (mainly), high CO2 and low pH
3) Highest blood flow of all tissues in the body
Clinical focus: tumors of carotid bodies: 3 different types
1) Familial
2) Sporadic
3) Hyerplastic
What activated carotid bodies?
Low blood oxygen
Cellular mechanisms mediating oxygen sensing (1-7 steps)
1) Low PO2
2) K+ Channels closes
3) Cell depolarizes
4) Voltage gated Ca2+ channels closes
5) Ca 2+ entry
6) Exocytosis of dopamine-containing vesicles
7) Signal to medullary centers to increase ventilation
