lecture 3 (respiratory)

Question 1

what muscles are recruited in faster breathing?

Answer 1

• phrenic nerve
• diaphragm
• internal intercostal muscles

Question 2

what is minute ventilation?

Answer 2

• 5 1/min

Question 3

what is the value of maximal voluntary ventilation?

Answer 3

• 125-175 l/min

Question 4

what is the normal range for arterial pH?

Answer 4

• 7.35-7.45

Question 5

what is the normal range for arterial PO2?

Answer 5

• 81-100 mmHg

Question 6

what is the normal range for arterial PCO2?

Answer 6

• 35-45 mmHg

Question 7

what is the structure of haemoglobin?

Answer 7

• alpha chain
• beta chain
• Fe2+ haemorrhage group

Question 8

what controls breathing?

Answer 8

• neurnonal control (higher centres, reflexes, rhythm generator)
• chemoreceptors (chemical control)

Question 9

what are the two types of chemoreceptors?

Answer 9

• central (brain stem)
• peripheral (arterial, reserve or back up)

Question 10

what say the function of the pons?

Answer 10

• modify the output of the medullary centres

Question 11

what is the rhythmic cycle of breathing derived from?

Answer 11

• medulla oblongata

Question 12

what is the dorsal respiratory group?

Answer 12

• mainly inspiratory neurones
• sends signals to diaphragm and intercostals

Question 13

what nerves bring input from the lungs to the DRG?

Answer 13

• vagus/glosopharyngeal nerves

Question 14

what does the ventral respiratory group contain?

Answer 14

• inspiratory neurones
• expiratory neurones

Question 15

what does the VRG do?

Answer 15

• sends impulses to larynx, pharynx, diaphragm and external intercostals

Question 16

what can and cant cross the blood brain barrier?

Answer 16

• CO2 can
• H+ and HCO3- cant readily cross

Question 17

what do central chemoreceptors respond to?

Answer 17

• changes in pH or CO2 levels

Question 18

what is the normal pH of the cerebral spinal fluid?

Answer 18

• 7.32

Question 19

what is CSF bicarbonate controlled by?

Answer 19

• choroid plexus

Question 20

what does the choroid plexus consist of?

Answer 20

• layer of endothelial filter cells
• surrounding are of capillaries and loose connective tissue
• acts as the blood brain barrier

Question 21

what does the CP fold into?

Answer 21

• villi around each capillary
• creates projections into the ventricles

Question 22

how is the CSF formed?

Answer 22

• as plasma is filtered from blood through epithelial cells

Question 23

what do CP epithelial cells actively transport?

Answer 23

• sodium, chloride and bicarbonate ions into the ventricles

Question 24

where are central chemoreceptors located?

Answer 24

• bilaterally in the medulla

Question 25

what does increasing the CO2 content do to chemoreceptors?

Answer 25

- increase the activity

Question 26

what does changing pH do to the activity of central chemoreceptors?

Answer 26

- activity increases as pH becomes more acidic

Question 27

where are the peripheral chemoreceptors located?

Answer 27

- carotid bodies in carotid sinus - aortic bodies in aortic arch

Question 28

what do peripheral chemoreceptors respond to?

Answer 28

- changes in partial pressure of oxygen - respond to low levels of arterial oxygen

Question 29

what occurs with low levels of oxygen?

Answer 29

- co2 decreases - respiration decreases

Question 30

what is chronic obstructive pulmonary disease?

Answer 30

- airway obstruction - can be caused by smoking, air pollution

Question 31

what're the characteristics of COPD?

Answer 31

- breathless - malnourishment - decreased BMI - pain breathing

Question 32

what is chronic bronchitis?

Answer 32

- chronic or recurrent excessive mucus secretion in the bronchial tree

Question 33

how does chronic bronchitis cause airflow limitation?

Answer 33

- leads to decrease in luminal diameter of airways - airway clogging/plugging with mucus - no air transfer

Question 34

what is emphysema?

Answer 34

- increase in normal size of air spaces - destruction of walls without obvious fibrosis - gradual damage of lung tissue and alveoli

Question 35

how does emphysema cause airway obstruction?

Answer 35

- destruction stops the air flow - mucus forming

Question 36

what are the structural changes in emphysema?

Answer 36

- distended respiratory bronchioles - destruction of alveoli

Question 37

how is airflow restricted in emphysema?

Answer 37

- airways kept open due to alveoli around them - airways not supported in emphysema - less air flow enters - increased pressure causes airways to constrict

Question 38

what is type 1 respiratory failure?

Answer 38

- low pO2 - emphysema due to V/Q mismatch

Question 39

what is type 2 respiratory failure?

Answer 39

- low pO2 and high pCO2 - require being under ventilation

Question 40

what are the causes of type 2 respiratory failure?

Answer 40

- central obstruction - mechanical failure (muscle weakness) - central loss of drive (opiates) - chronic lung disease

Question 41

what occurs in chronic COPD to chemoreceptors?

Answer 41

- adaptation of net to high CO2

Question 42

what is the risk of uncontrolled oxygen?

Answer 42

- death from hypercarbia (increased co2 in blood stream)

Question 43

what are the methods of oxygen delivery?

Answer 43

- medium conc mask - nasal prongs - venturi mask