Central Chemoreceptor – Control & Regulation of Breathing

00:00 Now central chemoreceptors will provide one of the basic feedbacks for the dorsal respiratory group neurons and the other respiratory control centers in the medulla How this works is that both hydrogen ions and bicarb unfortunately cannot cross the blood brain barrier.

00:23 It’s repelled.

00:24 The blood brain barrier repels these charged substances.

00:28 However, carbon dioxide, which is a gas, is allowed to move through the blood brain barrier into the brain extracellular fluid.

00:39 From there, it continues to diffuse onto the cerebrospinal fluid.

00:44 In the cerebrospinal fluid, there is an enzyme called carbonic anhydrase that helps this particular reaction of water and carbon dioxide to combine together to form a hydrogen ion and a bicarbonate.

00:58 It is then this hydrogen ion that is going to stimulate the central chemoreceptors and that can be seen here.

01:07 As hydrogen ions increase, there is an increase in the discharge of the central chemoreceptors.

01:16 So what are central chemoreceptors responsive to? The correct answer is hydrogen ions.

01:22 But how does it get a hydrogen ion is via an indirect process involving carbon dioxide diffusing into these extracellular fluids and cerebrospinal fluid before it can be sensed because it can’t directly sense a hydrogen ion from the blood.

01:42 Luckily, these particular central chemoreceptors are located in a very close proximity to both the dorsal respiratory group neurons and the ventral respiratory group neurons.

01:53 This allows for an integrated process and quick signalling between different units.