FAQ on Control of Breathing

  >   Rahul's Noteblog   >   Notes on Pulmonology   >   FAQ on Control of Breathing

Where is the respiratory centre located in the brain?

The respiratory center is located in the brain stem.

What are the central and peripheral chemoreceptors, where are they located, how do they work in the control of respiration?

Sensory neurons that are responsive to chemicals are termed chemoreceptors. Central chemoreceptors are located in the medulla oblongata in the central nervous system, and peripheral chemoreceptors are located in the aortic bodies, plus, clusters of chemoreceptors are located in the wall of the arch of aorta and carotid bodies.

Chemoreceptors respond to levels of CO2, O2 and H+ in the blood. When these levels increase, chemoreceptors are engaged in a negative feedback system, and this causes the respiratory are to become more active and the rate and depth of breathing increases allowing inhalation of more O2 and exhalation of more CO2 until of CO2, O2 and H+ in the blood are back to normal.

Is breathing under conscious control, or is it an automatic response?

It depends. Breathing is a passive (automatic) process at rest since there is no muscle contraction. However, during exercise, breathing becomes an active process because more oxygen needs to be inhaled and more CO2 needs to be exhaled, hence, it comes under conscious control.

What is the primary ventilatory drive in someone at rest, i.e., what is it that drives us to breathe?

This is done by the contraction of the diaphragm and external intercostal muscles. This causes, according to Boyle’s Law, the intrathoracic pressure to fall leading to inrush of atmospheric air into lungs.

What is the primary ventilatory drive during exercise?

During exercise, active contraction of the expiratory muscles (diaphragm and external intercostal muscles) helps to expel air from the lungs.

Describe how the respiratory centre controls a normal inspiration and expiration:

The respiratory center consists of three types of neurons, namely, the medullary rhythmicity area, the pneumotaxic area, and the apenustic area.

Medullary rhythmicity area controls the basic rhythm of respiration.

Pneumotaxic area helps coordinate the transition between inhalation and exhalation

Apenustic area also coordinates the transition between inhalation and exhalation.

What is the role of the Hering-Breuer reflex?

This is the production of apnea (stopping of breathing) due to large lung inflation and augmentation of expiratory muscle contraction. Very important when infants are concerned. It has two parts: inflation and deflation components.


Low oxygen levels in blood.


A higher than normal P02level in the blood.


Under breathing to the extent that the blood carbon dioxide level is elevated, may be manifested by carbon dioxide narcosis.


Abnormally rapid, deep breathing.

Additional Reading:

Basic Pulmonology

1. Lung Mechanics
2. Alveolar-Blood Gas Exchange
3. Gas Transport and Regulation of Respiration
4. Four Causes of Hypoxemia
5. Control of Respiration
6. Systemic vs Pulmonary Circulation FAQ
7. Principles of Gas Exchange in Lungs
8. Hypoxia, Hypoxemia & Hemoglobin-Oxygen Saturation Curve
9. FAQ on Mechanics of Breathing
10. FAQ on Control of Breathing
11. Criteria for Transudate Pleural Effusion
12. Light's Criteria for Exudate Pleural Effusion
13. Notes on Lung Sounds
14. Patient with Acute Respiratory Distress Syndrome (ARDS)
15. Management of Acute Deep Venous Thrombosis
16. Notes on Asthma Treatment

Pulmonology Videos

1. Video of Pulmonology Examination in a Clinical Setting

Related Topics

1. Histology of the Respiratory System
2. Upper and Lower Respiratory Disorders
3. Pulmonary Examination for Internal Medicine

Medical Images

Useful Medical Images & Diagrams (link opens in a new window)

Random Pages:

My Experience during the Iraqi Invasion of Kuwait My First Computer - Pentium with Windows 95
Video of me playing Titanic Piano Theme: The Portrait Notes on Female Reproductive System
Notes on Back and Nervous System Notes on Rickettsia
Notes on Gluconeogenesis What are the most common causes of aortic stenosis?
Significance of Measuring Albumin while with Calcium Levels Notes on Functions of the Liver
Notes on Basic Gastrointestinal Physiology Why did I become a doctor?
Pictures of old Kuwaiti Dinars What is an ELEK`s Test?
Why did I decide to become a doctor? Medical School Admissions Essay Video: Titanic Piano Theme: The Portrait
Corporate Failure: The Enron Case My Experience during the Iraqi Invasion of Kuwait
USMLE Blood Lab Values Regulation of Heart Rate by Autonomic Nervous System
Images of Antibodies Video of me playing Unknown Easy Blues Piano
Notes on Male Reproductive System Differentiation and Anatomy of a Blastocyst
Notes on Cell Components Notes on Nervous Tissue
Voices from Hell: My Experience in Mussoorie, India Video of Cardiology Examination in a Clinical Setting

Please Do Not Reproduce This Page

This page is written by Rahul Gladwin. Please do not duplicate the contents of this page in whole or part, in any form, without prior written permission.