Question

3. Describe the receptor/s (peripheral and central), afferent pathways, central integration, and efferent neural pathways that: borclinars doinw

Answer 1

3. Basis of Inspiration

MECHANICAL: Active contraction of inspiratory muscles, i.e. the Diaphragm

NEURAL: Phrenic motoneurons located within the ventral horn (lamina IX) of the cervical spinal cord (C₃-C₅) innervate the diaphragm.

Breathing is regulated by the autonomic nervous system, which means it does not require input from the cerebral cortex (although it can contribute).

MECHANICAL: Relaxation of the diaphragm and passive exhalation from elastic recoil of the lungs and chest wall

NEURAL: Decreased firing of the Phrenic Nerve

[Neural Basis of Rate and Depth of Breathing]

Respiratory rate is determined by the interval between bursts of phrenic nerve action potentials.

Tidal volume is determined by the strength of diaphragm contraction, which is determined by the number of phrenic motor units recruited.

Respiratory Control System

Central Controller = Brain Stem

Effectors = Lungs

Sensors = Carotid Bodies + Base of 4th ventricle of the Brain

Automatic Control of Breathing

There is a breathing center in the Pons called the Pontine Respiratory Group (PRG).

There are breathing centers in the Medulla, which are more important. These include the Dorsal Respiratory Group (DRG) and the Ventral Respiratory Group (VRG).

-If the spinal cord is transected below the Medulla, you will not be able to breathe.

-The spinal cord is transected above the Pons, breathing will continue