Neural control of respiration (like neural control of many other physiological functions, micturition, for example) is highly complex and not fully elucidated. Research is still going on to determine the centers in the brain and their complex interactions. There may be variations of opinion between different researchers depending on newer findings.
Every effort has been made to keep this information as current and authoritative as possible, yet in a simple enough form for the student to understand and digest the information.
Dr Sanjoy Sanyal, Professor and Course Director of Neuroscience and FCM-III Neurology in Caribbean created this PPTX after studying this complex topic for a very long time.
Tags: Respiration, Breathing, Respiratory Centers, Brainstem, Apneustic Breathing, Biots Breathing, Cheyne-Stokes, Ataxic, Agonal, Kussmaul, Brainstem Reticular Nuclei, NTS, Locus Ceruleus, Fastigial, Raphe nucleus, Vagus, RTN nucleus, pFRG nucleus, Kolliker-Fuse, PBC nucleus, RVL nucleus
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Educational Value: A very complex and poorly understood topic has been rendered in as simple a format and style as possible, so as to make it easily digestible to any Basic Science medical student and Medical Resident
Gas exchange between the alveoli and the pulmonary capillary blood occurs by diffusion, as will be discussed in the next chapter. Diffusion of oxygen and carbon dioxide occurs passively, according to their concentration differences across the alveolar-capillary barrier. These concentration differences must be maintained by ventilation of the alveoli and perfusion of the pulmonary capillaries.
Alveolar ventilation brings oxygen into the lung and removes carbon dioxide from it. Similarly, the mixed venous blood brings carbon dioxide into the lung and takes up alveolar oxygen. The alveolar Image not available. and Image not available. are thus determined by the relationship between alveolar ventilation and pulmonary capillary perfusion. Alterations in the ratio of ventilation to perfusion, called the Image not available., will result in changes in the alveolar Image not available. and Image not available., as well as in gas delivery to or removal from the lung.
Alveolar ventilation is normally about 4 to 6 L/min and pulmonary blood flow (which is equal to cardiac output) has a similar range, and so the Image not available. for the whole lung is in the range of 0.8 to 1.2. Image not available. However, ventilation and perfusion must be matched on the alveolar-capillary level, and the Image not available. for the whole lung is really of interest only as an approximation of the situation in all the alveolar-capillary units of the lung. For instance, suppose that all 5 L/min of the cardiac output went to the left lung and all 5 L/min of alveolar ventilation went to the right lung. The whole lung Image not available. would be 1.0, but there would be no gas exchange because there could be no gas diffusion between the ventilated alveoli and the perfused pulmonary capillaries.
Oxygen is delivered to the alveolus by alveolar ventilation, is removed from the alveolus as it diffuses into the pulmonary capillary blood, and is carried away by blood flow. Similarly, carbon dioxide is delivered to the alveolus in the mixed venous blood and diffuses into the alveolus in the pulmonary capillary. The carbon dioxide is removed from the alveolus by alveolar ventilation. As will be discussed in Chapter 6, at resting cardiac outputs the diffusion of both oxygen and carbon dioxide is normally limited by pulmonary perfusion. Thus, the alveolar partial pressures of both oxygen and carbon dioxide are determined by the Image not available. If the Image not available. in an alveolar-capillary unit increases, the delivery of oxygen relative to its removal will increase, as will the removal ...
Gas exchange between the alveoli and the pulmonary capillary blood occurs by diffusion, as will be discussed in the next chapter. Diffusion of oxygen and carbon dioxide occurs passively, according to their concentration differences across the alveolar-capillary barrier. These concentration differences must be maintained by ventilation of the alveoli and perfusion of the pulmonary capillaries.
Alveolar ventilation brings oxygen into the lung and removes carbon dioxide from it. Similarly, the mixed venous blood brings carbon dioxide into the lung and takes up alveolar oxygen. The alveolar Image not available. and Image not available. are thus determined by the relationship between alveolar ventilation and pulmonary capillary perfusion. Alterations in the ratio of ventilation to perfusion, called the Image not available., will result in changes in the alveolar Image not available. and Image not available., as well as in gas delivery to or removal from the lung.
Alveolar ventilation is normally about 4 to 6 L/min and pulmonary blood flow (which is equal to cardiac output) has a similar range, and so the Image not available. for the whole lung is in the range of 0.8 to 1.2. Image not available. However, ventilation and perfusion must be matched on the alveolar-capillary level, and the Image not available. for the whole lung is really of interest only as an approximation of the situation in all the alveolar-capillary units of the lung. For instance, suppose that all 5 L/min of the cardiac output went to the left lung and all 5 L/min of alveolar ventilation went to the right lung. The whole lung Image not available. would be 1.0, but there would be no gas exchange because there could be no gas diffusion between the ventilated alveoli and the perfused pulmonary capillaries.
Oxygen is delivered to the alveolus by alveolar ventilation, is removed from the alveolus as it diffuses into the pulmonary capillary blood, and is carried away by blood flow. Similarly, carbon dioxide is delivered to the alveolus in the mixed venous blood and diffuses into the alveolus in the pulmonary capillary. The carbon dioxide is removed from the alveolus by alveolar ventilation. As will be discussed in Chapter 6, at resting cardiac outputs the diffusion of both oxygen and carbon dioxide is normally limited by pulmonary perfusion. Thus, the alveolar partial pressures of both oxygen and carbon dioxide are determined by the Image not available. If the Image not available. in an alveolar-capillary unit increases, the delivery of oxygen relative to its removal will increase, as will the removal ...
Ventilation perfusion ratio (The guyton and hall physiology)Maryam Fida
Ventilation perfusion ratio is :
“The ratio of alveolar ventilation and the amount of blood that perfuse the alveoli”.
FORMULA
It is expressed as VA/Q.
VA is alveolar ventilation
Q is the blood flow (perfusion)
Normal value of ventilation perfusion ratio is about
0.8
VA is 4.2 L /min
Q is 5.5 L/min (Same as Cardiac output)
So VA/Q = 4.2/5.5 = 0.8
If VA becomes zero ratio becomes zero
If Q becomes zero ratio becomes infinite.
If ratio becomes zero or infinite then there is no gaseous exchange. So this ratio indicates the efficiency of gaseous exchange in lungs.
In standing or sitting position this ratio is not uniform in all parts of the lungs.
In standing position, in upper parts of lungs there is almost no blood flow so normally in upper parts of lungs the ratio is higher may be near 3.
In lower part of lungs, there is more blood flow so the ratio is decreased may be 0.6.
In certain diseases the VA/Q ratio is higher which means perfusion is inadequate i.e. in some parts of lungs the alveoli are non functional or partially functional. This is seen in cases of pulmonary thrombosis or embolism.
When there is higher VA/Q ratio, PO2 and PCO2 in the alveolar air resembles the values in the inspired air.
When exchange is not occurring because of lack of perfusion, inspired air goes to alveoli, as there is no exchange occurring so the same values of PCO2 and PO2 as in inspired air.
Like heartbeat, breathing must occur in a continuous, cyclic pattern to sustain life processes.
Inspiratory muscles must rhythmically contract and relax to alternately fill the lungs with air and empty them.
The rhythmic pattern of breathing is established by cyclic neural activity to the respiratory muscles
Ventilation perfusion ratio (The guyton and hall physiology)Maryam Fida
Ventilation perfusion ratio is :
“The ratio of alveolar ventilation and the amount of blood that perfuse the alveoli”.
FORMULA
It is expressed as VA/Q.
VA is alveolar ventilation
Q is the blood flow (perfusion)
Normal value of ventilation perfusion ratio is about
0.8
VA is 4.2 L /min
Q is 5.5 L/min (Same as Cardiac output)
So VA/Q = 4.2/5.5 = 0.8
If VA becomes zero ratio becomes zero
If Q becomes zero ratio becomes infinite.
If ratio becomes zero or infinite then there is no gaseous exchange. So this ratio indicates the efficiency of gaseous exchange in lungs.
In standing or sitting position this ratio is not uniform in all parts of the lungs.
In standing position, in upper parts of lungs there is almost no blood flow so normally in upper parts of lungs the ratio is higher may be near 3.
In lower part of lungs, there is more blood flow so the ratio is decreased may be 0.6.
In certain diseases the VA/Q ratio is higher which means perfusion is inadequate i.e. in some parts of lungs the alveoli are non functional or partially functional. This is seen in cases of pulmonary thrombosis or embolism.
When there is higher VA/Q ratio, PO2 and PCO2 in the alveolar air resembles the values in the inspired air.
When exchange is not occurring because of lack of perfusion, inspired air goes to alveoli, as there is no exchange occurring so the same values of PCO2 and PO2 as in inspired air.
Like heartbeat, breathing must occur in a continuous, cyclic pattern to sustain life processes.
Inspiratory muscles must rhythmically contract and relax to alternately fill the lungs with air and empty them.
The rhythmic pattern of breathing is established by cyclic neural activity to the respiratory muscles
Description (with pictures) of successful (and failed) lunar landings - supplemented with numerous pictures of Lunar Surfaces, with Craters and all.
Disclaimer and Credits
All material (Text, Images, Graphics etc.) in these slides have been procured from publicly available sources of ISRO and other agencies, which includes ISRO partners. There are selected images from NASA and Wikipedia also, where relevant, also procured from freely available public resources, with attribution. Some images and text have been individually acknowledged. Others have been collectively credited through this Disclaimer page. The author makes no copyright claims on any material.
They have been sorted, edited as relevant, collated, compiled and inserted to align them with the sequence of the slides, as deemed fit by the author. They have been posted with academic altruism in mind, for those interested in Astrophysics and Astronomy and related technology, like the author. There is no commercial or promotional motivation involved anywhere.
The author is not an Astrophysicist or an Astronomer. The author does not work for ISRO, NASA or any tech company. The author is a nerd who loves technology, Astrophysics and Astronomy and who dabbles in related developments of ISRO, NASA etc. during his spare time, as an intellectual hobby. Thus, he satiates his academic appetite, learns in the process and wishes to share them with like-minded people.
At the time of publication, all material has been updated and is deemed to be accurate. If any errors are detected by the reader(s) the author will be happy to be corrected. The responsibility for any errors are solely the author’s and not that of the parent organization(s).
Here’s is wishing everyone a happy armchair space exploration on this occasion of New Year 2024!
Updated as on 31 January 2024
JAXA being an ethical Space Agency disclosed the real reason why SLIM Lander could not communicate for 1st week after soft-landing on Moon.
Picture released by JAXA
A. SLIM lost one of its Engines during descent
B. Because of the resultant asymmetric Thrust, SLIM landed on Lunar Surface upside down
C. Resulting in its Solar Panels facing away from Sun (See the direction of shadows to determine relative position of Sun and Solar Panels)
MARS Images ISRO-NASA-Compiled by Sanjoy SanyalSanjoy Sanyal
MCC Imaging Timeline
28 September 2014 – MOM (Mars Orbiter Mission) controllers published the spacecraft's first global view of Mars. The image was captured by the Mars Color Camera (MCC)
4 March 2015 – MCC was returning new images of Martian surface
24 September 2015 – ISRO released ‘Mars Atlas’, a 120-page scientific atlas containing images and data from MOM’s 1st year in orbit
19 May 2017 – MOM reached 1,000 days (973 sols (Martian Days)) in orbit around Mars. In that time, the spacecraft completed 388 orbits of the planet and relayed > 715 images back to Earth
24 September 2018 – MOM completed 4 years in its orbit around Mars, although the designed mission life was only 6 months. Over these years, MOM’s MCC captured > 980 images that were released to the public
24 September 2019 – MOM completed 5 years in orbit around Mars, sending 2 TB of imaging data
1 July 2020 – MOM captured a photo of Mars satellite Phobos from 4,200 km away
18 July 2021 – MCC captured full disc image of Mars from an altitude of 75,000 km with spatial resolution about 3.7 km
October 2022 – MCC produced 1,100+ images before retirement
DISCLAIMER
All material (Text, Images, Graphics etc.) in these slides have been procured from publicly available sources of ISRO and other agencies, which includes ISRO partners. There are selected images from NASA also, where relevant, also procured from freely available public resources. Instead of individually acknowledging each image they have been collectively credited through this Disclaimer page. The author makes no copyright claims on any material.
They have been sorted, edited as relevant, collated and inserted to align them with the sequence of the slides, as deemed fit by the author. They have been posted with academic altruism in mind, for those interested in Astrophysics and Astronomy and related technology, like the author. There is no commercial or promotional motivation involved anywhere.
The author is not an Astrophysicist or an Astronomer. The author does not work for ISRO, NASA or any tech company. The author is a nerd who loves technology, Astrophysics and Astronomy and who dabbles in related developments of ISRO, NASA etc. during his spare time as an intellectual hobby. Thus, he satiates his academic appetite, learns in the process and wishes to share them with like-minded people.
At the time of publication, all material has been updated and is deemed to be accurate. If any errors are detected by the reader(s), I shall be happy to be corrected. The responsibility for any errors are solely mine and not that of the parent organizations.
Here’s is wishing everyone a happy armchair space exploration on this occasion of New Year 2024!
Aditya-L1 Suit Images ISRO - Compiled by Sanjoy Sanyal.pptxSanjoy Sanyal
Solar Ultraviolet Imaging Telescope (SUIT):
Instrument on board Aditya-L1 Spacecraft has successfully captured the first full-disk images of the Sun in 200-400 nm Wavelength range
SUIT captures images of the Sun's Photosphere and Chromosphere in this wavelength range using various Filters
20 November 2023: SUIT payload was powered ON
Successful pre-commissioning phase
6 December 2023: SUIT captured its first light science images
Images: Taken using 11 different Filters (Slide 4), include the first-ever full-disk representations of the Sun in Wavelengths ranging from 200 to 400 nm, excluding Ca II h
Notable Features: Sunspots, Plage (Chromosphere variant of Faculae), Limb Darkening, and Quiet Regions of Sun, as marked in Mg II h image (Slide 7), provide scientists with insights into the intricate details of Sun's Photosphere and Chromosphere
SUIT observations will help scientists study the dynamic coupling of magnetized solar atmosphere and assist them in determining the effects of solar radiation on Earth's climate
DISCLAIMER
All material (Text, Images, Graphics etc.) in these slides have been procured from publicly available sources of ISRO and other agencies, which includes ISRO partners. There are selected images from NASA also, where relevant, also procured from freely available public resources. Instead of individually acknowledging each image they have been collectively credited through this Disclaimer page. The author makes no copyright claims on any material.
They have been sorted, edited as relevant, collated and inserted to align them with the sequence of the slides, as deemed fit by the author. They have been posted with academic altruism in mind, for those interested in Astrophysics and Astronomy and related technology, like the author. There is no commercial or promotional motivation involved anywhere.
The author is not an Astrophysicist or an Astronomer. The author does not work for ISRO, NASA or any tech company. The author is a nerd who loves technology, Astrophysics and Astronomy and who dabbles in related developments of ISRO, NASA etc. during his spare time as an intellectual hobby. Thus, he satiates his academic appetite, learns in the process and wishes to share them with like-minded people.
At the time of publication, all material has been updated and is deemed to be accurate. If any errors are detected by the reader(s), I shall be happy to be corrected. The responsibility for any errors are solely mine and not that of the parent organizations.
Here’s is wishing everyone a happy armchair space exploration on this occasion of New Year 2024!
Charting Neural Pathways in Schizophrenia and BPD-Chicago Conference 2016 - S...Sanjoy Sanyal
This was presented by Dr. Sanjoy Sanyal, Professor, Surgeon, Neuroscientist, Informatician, at 2nd International Conference on Brain Disorders and Therapeutics, Chicago, USA, October 26-28, 2016
Types of Schizophrenia
Types of Bipolar Disorder (BPD)
DTI Findings in Schizophrenia / BPD
Videos of White Matter Affected in Psychosis
Brain Network Concepts
Basal Forebrain Components and VTA
Videos of Meso-limbic / Meso-cortical Tracts
Receptors in Psychotic Disorders
Videos of Pathophysiology in Schizophrenia 1 and 2 – Rx Principles
Future Research Possibilities
Summary and Conclusion
Thank you for watching.
Aorta–IVC–Kidney Dissection and Surgical Correlations - Dr Sanjoy SanyalSanjoy Sanyal
Educational PPTX created by Dr. Sanjoy Sanyal; Professor, Department Chair, Surgeon, Neuroscientist and Medical Informatician
It shows the surgical anatomy of the posterior abdominal contents, with special emphasis on the aorta, IVC and Kidney-Ureters. The specimen was harvested from a cadaver.
With real-time narration and relevant captions, it enhances the learning experience by means of a trimodal learning style approach - Visual, Auditory, Textual.
Thank you for watching. If you have any questions or comments, please put them in the comments section below. Have a nice day!
Educational Video created by Dr Sanjoy Sanyal; Professor, Surgeon, Medical Informatician and Department Chair in the Western Hemisphere.
A section of the anterior chest wall from a cadaver is described - the Bones, Muscles, Vessels, and some Clinical Correlations
Camera person is Ms. Selvie Krishna, an enthusiastic student with her Blackberry.
Errata Corrigendum: There is an inadvertent error in my narration, where I mentioned Sternum instead of Vertebral Column. The same was corrected immediately thereafter in my narration, and the error and correction have also been captioned in the body of the video.
Thank you for watching. If there are questions or comments, put them in the comments section below.
Dissections of the calf and its functional and surgical aspects have been discussed in real time by Dr. Sanjoy Sanyal, Professor, Surgeon, Neuroscientist and Medical Informatician.
Important points discussed are: Triceps surae, Gastrocnemius, Soleus, Plantaris, Tendo calcaneus, Love and Whelan classification, Plantar reflex, calcaneal bursitis, calcaneal tendinitis, calcaneal tendon rupture, Gastrocnemius strain, tennis leg, PAES, accessory soleus
Educational importance lies in the following aspects: Combination of audio, video, graphics and textual description in real time
Surgical Aspects of Popliteal Fossa - Dr. Sanjoy SanyalSanjoy Sanyal
Dissection of the popliteal fossa and its surgical aspects has been discussed in real time by Dr. Sanjoy Sanyal, Professor, Surgeon and Neuroscientist.
Important points discussed are: Popliteal fossa, Palpation, Popliteal artery entrapment, PAES, Popliteal aneurysm, Popliteal AV fistula, Popliteal hemorrhage, Genicular anastomosis, Popliteal cyst, Baker cyst, Morrant baker cyst, Heidelberg classification, Love and Whelan classification
Educational importance lies in the following aspects: Combination of audio, video, graphics and textual description in real time
Surgical Anatomy of Cadaveric Abdominal Viscera - Dr Sanjoy SanyalSanjoy Sanyal
Educational Video created by Dr Sanjoy Sanyal; Professor, Surgeon, Neuroscientist and Medical Informatician
A section of abdominal viscera from a cadaver has been described - Stomach, Spleen, Colon, Greater Omenutm, with some clinical and surgical correlations
Corrigendum: Please disregard the inadvertent error when the Gastrosplenic ligament is being described - GS ligament contains Gastro-epiploic vessels; Spleno-renal ligament contains the Splenic vessels
This was presented by Dr Sanjoy Sanyal at the 2016 International Education Conference in Orlando, FL on 4 January 2016 in Disney's Boardwalk Inn.
It was voted the best paper presentation of the session by the attendees.
Educational Video created by Dr Sanjoy Sanyal; Professor, Surgeon and Medical Informatician
Deals with Blended / Hybrid Learning, Rotation Model, Flipped Classroom, Student responses, Audience Response System Clicker,
Abnormal Right Vertebral Artery MRA Sequence - Sanjoy SanyalSanjoy Sanyal
This is an MR Angiography sequence of a 46-year old male patient who was being investigated for TIA. The image sequence shows 3-D Time of Flight (TOF) Spoiled Gradient Recall (SPGR) Echo Acquisition images. It shows the Vertebrobasilar and Carotid systems of Cerebral circulation. An incidental finding was abnormal Right Vertebral artery - Narrow, Double, Accessory, Communication with Right Internal Carotid. The best way to visualize the image is by slideshow - imagine the head is rotating clockwise. There are plenty of labels in the images to guide the viewer.
Ionizing Radiation in Surgery - Sanjoy SanyalSanjoy Sanyal
Ionizing radiations exert their biological effects by excitation and ionization of molecules within cells. In terms of energy deposited within cells, ionizing radiations are the most potent of all physical and chemical agents
Lasers in Surgery Systemic Applications Part-III - Sanjoy SanyalSanjoy Sanyal
Applications of lasers in organ-systems of the body are at the cross-roads today, with limitless horizon ahead of it. The authors dwell upon the applications in important oragns of the human body.
Illustrated Surgical GI Endoscopy - Sanjoy SanyalSanjoy Sanyal
Therapeutic endoscopy has made considerable inroads in the treatment of surgical disorders of the GI tract. This has been brought about by technological innovations in the hardware and the ingenuity of the clinician in accessing the lesion.
Lasers in Surgery Specific Applications Part-II - Sanjoy SanyalSanjoy Sanyal
Experiments with lasers are going on a hectic pace in order to improve upon the existing applications of lasers in surgery. However it behoves the surgeon to be cognizant of its potential hazards and to take appropriate precautions.
Automatic Physiological Assessment in Surgery Computer Program - Sanjoy SanyalSanjoy Sanyal
Computer programs for automatic interpretation of physiological variables in critically ill surgical patients are quick and efficient decision-making aids to the clinician.
Surgical Aspects of Colorectal Endoscopy Part-IV - Sanjoy SanyalSanjoy Sanyal
Colorectal endoscopy differs significantly from UGI endoscopy. The authors describe some differential aspects, some common and some exotic coloscopic findings.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
How to Split Bills in the Odoo 17 POS ModuleCeline George
Bills have a main role in point of sale procedure. It will help to track sales, handling payments and giving receipts to customers. Bill splitting also has an important role in POS. For example, If some friends come together for dinner and if they want to divide the bill then it is possible by POS bill splitting. This slide will show how to split bills in odoo 17 POS.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
Neural Control of Respiration - Abnormal Breathing Patterns - Sanjoy Sanyal
1. Dr Sanjoy Sanyal, MBBS, MS (Surgery), MSc (Royal College
of Surgeons of Edinburgh), ADPHA
Professor and Course Director of Neuroscience and FCM-
III Neurology
It’s as natural as breathing.
Well, maybe not!
2. Chemoreceptors (CR)
Chemoreceptors (CRs)
monitor Body Fluid chemistry
and respond to their H+ (pH),
PCO2, PO2 concentrations
Input from CRs to CNS and
Output from CNS to Lungs
drive Alveolar Ventilation
Types of CR:
Central CR
(CCR)
Peripheral CR
(PCR)
3. Central Chemoreceptors (CCRs)
1. Pre-Bötzinger Complex (PBC) in Rats
2. Retrotrapezoid Nucleus (RTN) in
Pons
3. Parafacial Respiratory Group (pFRG)
in Medulla
4. Raphe Nuclei in Brainstem Reticular
Formation
5. Locus Ceruleus in Pons
6. Nucleus Tractus Solitarius (NTS) in
Medulla
7. Fastigial Nucleus in Cerebellum
(PBC, RTN, pFRG, Locus Ceruleus are
also Respiratory Rhythm centers)
Location: Close to
CSF surfaces
of Medulla,
Pons,
Cerebellum;
Bathed in CSF;
Monitors CSF
H+ and PCO2
directly
4. Central Chemoreceptors (CCRs)
Receptor Type: H+ / PCO2 Receptor;
NO PaO2 receptors in CCR
Stimulus: CSF H+ (Most Sensitive),
CSF PCO2, Arterial PCO2
(Indirectly); NOT Arterial PO2
Less Sensitive To: Systemic Arterial
pH (Because H+ passes very slowly
across Blood-CSF Barrier)
Adaptation: within 12-24 hrs; Due to
pumping of HCO3
- in/out of CSF
There are NO
PO2
Receptors in
the CCR
5. CCR – Bottom Line
CCRs are very sensitive
Provide main drive to ventilation under normal
conditions at Sea Level Atmospheric Pressure
Ventilation responds much more to moderate
↑Arterial PCO2 (Hypercapnia) than to large ↓in
Arterial PO2 (Hypoxia), because of lack of central
PO2 Receptors in CCR
6. CCR Respiratory Stimulants
Progesterone acts on CCR via Steroid Receptor-
Mediated Mechanism to help Respiration
Naloxone is -Opiate Receptor Antagonist, Used
in Opioid-induced Central Respiratory
Depression
Doxapram is PCR and CCR Stimulant;
Overcomes Opioid-induced Central Respiratory
Depression
Acetazolamide (Carbonic Anhydrase Inhibitor)
causes Acidification of CSF, acting as CCR
Respiratory Stimulant, especially at High Altitude
7. Peripheral Chemoreceptors (PCR)
Locations: Aortic and Carotid Bodies;
Bathed in Arterial Blood; Monitor
Arterial Blood PO2 directly
1. Aortic Bodies: Near Aortic Arch;
CN10 Afferent
2. Carotid Bodies (Most important):
Near Carotid Sinus at Carotid
Bifurcation; CN9 Afferent
[Very small structure; Receives maximum
Blood per Gm of tissue; Meets metabolic
requirements by utilizing O2 dissolved in
Blood; Type 1 Glomus Cells are main
sensors of Hypoxia]
8. Peripheral Chemoreceptor (PCR)
Receptor Types: PO2 Receptor (Mainly); Also H+ /
PCO2 Receptor
Stimulus: Arterial PO2 (Most sensitive); Monitor
PO2 (Partial Pressure of O2 in Blood, which is O2
Dissolved in blood), NOT O2 Content (O2 in Hb)
Less Sensitive To: Systemic Arterial pH / PCO2;
Very small contribution to normal drive for
ventilation
Adaptation: Nil (Receptor keeps firing so long as
Arterial Hypoxic Stimulus exists)
9. PCR – Bottom Line
When Systemic Arterial PaO2 >100 mmHg:
There is NO Stimulus to PO2 receptors
PCRs do NOT contribute to drive for Normal
Ventilation
When Systemic Arterial PaO2 <100 mmHg:
Strong Stimulus to PO2 receptors, ↑Drive for
Alveolar Ventilation
Main Drive for ventilation in Hypoxemic Hypoxia
This drive increases with CO2 Retention
(Hypercapnia)
10. PCR Respiratory Stimulants
Almitrine Bismesylate is Carotid Body (PCR)
stimulant
Doxapram is PCR and CCR Stimulant;
Overcomes Opioid-induced Central Respiratory
Depression
General Information:
Partial Pressure of Gases in Blood / CSF is
measured in Pascals (Pa) / kiloPascals (kPa).
1 kPa = 7.5 mm Hg; 133 Pa = 1 mm Hg
11. Summary of CCRs and PCRs
CCR PCR
Location Medulla, Pons,
Cerebellum
Aortic / Carotid
Bodies
Samples What CSF Arterial Blood
Receptor Type H+ / PCO2 PaO2
Stimulus CSF H+ (Main);
CSF PCO2;
Arterial PCO2
(Indirectly)
Arterial PO2
(Main); Arterial
pH, PCO2 (Less)
Less Sensitive
To
Systemic Arterial
pH
Systemic Arterial
pH / PCO2
Adaptation 12 – 24 hours Nil
12. Respiratory Rhythm / Control
Afferents: From Mechano-
receptors in:
Lungs: Via Thoracic
Cardiopulmonary Splanchnic
Nerves (T2-5)
Intercostal Muscles: Via
Intercostal Nerves
Diaphragm: Via Phrenic
Nerve (C3-5)
Overview:
Input from CRs
to CNS and
Output from
CNS to Lungs
drive Alveolar
Ventilation
13. Respiratory Rhythm / Control
Afferents: From Peripheral and
Central Chemo-receptors:
Carotid Body
Aortic Body
CCRs: 7 (Slide #3)
14. Respiratory Rhythm / Control
Rhythm Centers:
Rostroventrolateral
(RVL) Nucleus in
Medulla
Kölliker-Fuse Nucleus
Para-brachial Complex
Locus Ceruleus in
Pons (This is also a
CCR)
Inspiratory Centers:
Pre-Bötzinger Complex
(PBC) in rats only (This is
also a CCR)
Expiratory Centers: (These
are also CCRs)
RTN
pFRG
15. Respiratory Rhythm / Control
Pathway 1:
Carotid Body (CN9) / Aortic
Body (CN10)
→ NTS (CCR)
→ RTN (CCR / Expiratory
Center)
→ Respiratory Rhythm
17. Respiratory Rhythm / Control
Central Respiratory Integration
Above-mentioned centers in Brainstem Reticular
Formation Generate central Respiratory Drive
Govern inherent Respiratory Rhythm
Transmit to Upper Airway and to Main and
Accessory Respiratory Muscles
Bottomline:
Input from CRs to CNS and Output from CNS to
Lungs drive Alveolar Ventilation
18. Respiratory Rhythm / Control
Autonomic Control:
SNS: Thoracic CP
Splanchnic Nerve
(Sympathetic from T2-5
Ganglia) relaxes Bronchi
PSNS: Dorsal Nucleus of
Vagus (Parasympathetic)
constricts Bronchi
Supramedullary
Areas: Cortex / Sub-
cortex Initiate or
Modulate breathing
with Volition,
Emotion, Exercise etc
19. Summary CCR Respiratory Rhythm Centers
CCR Inspiratory
Centers
Expiratory
Centers
Other Rhythm Centers
Pre-Botzinger Complex
(PBC) (Rats)
PBC (Rats) Rostroventrolateral
(RVL) Nucleus in
Medulla
Retrotrapezoid
Nucleus (RTN) in Pons
RTN Kolliker-Fuse Nucleus
Parafacial Respiratory
Group (pFRG)
pFRG Parabrachial Complex
Raphe Nuclei in
Brainstem Reticular
Formation
Locus Ceruleus (Pons) Locus Ceruleus (Pons)
Nucleus Tractus
Solitarius (NTS) in
Medulla
Fastigial Nucleus in
Cerebellum
20. Respiratory Control – Clinical Aspects
Spinal Cord Lesions:
Complete lesion at or above C3 Spinal Segment
interrupt Diaphragmatic Respiration
Complete lesion at or below C6 Spinal Segment
will not
Respiratory Depressants:
Opioids act on -Opiate Receptors in Brainstem
Reticular Formation and Inhibit Brainstem
Respiratory Rhythm (See Naloxone in Slide 24)
21. Respiratory Control – Clinical Aspects
Brainstem Pathology:
Breathing control can be disturbed by many
Brainstem Pathology.
Previously undiagnosed such pathology may be
revealed by Abnormal Breathing during Sleep
Sleep-Awake States:
Important in regulating breathing
Thus, respiratory control abnormalities are most
often evident during Sleep, or during transition
from Sleep to Wakefulness (Next 2 slides)
22. Respiratory Control – Clinical Aspects
Central (Diaphragmatic) Sleep Apnea:
Inhibition of ‘Respiratory Center’ (RVL in Caudal
Brainstem Reticular Formation)
→ Intermittent Diaphragmatic Arrest, causing
(a)Cheyne-Stokes Respiration (60-second
Hyperventilation → Apnea) in
(b)Elderly
23. Respiratory Control – Clinical Aspects
Ondine's Curse vs. Locked-in Syndrome: Distinguish
Brainstem (Volitional) from Supramedullary
(Autonomic) regulatory failure
Former loses Autonomic Respiratory control and
requires Volitional Breathing for survival. So patient has
Hypoventilation during Sleep
Latter loses CST / CBT in Pons that is required for
Volitional Breathing, but retains Autonomic Control
24. Respiratory Stimulants
Progesterone acts on CCR via Steroid Receptor-
Mediated Mechanism to help Respiration
Almitrine Bismesylate is Carotid Body (PCR)
Stimulant
Naloxone is -Opiate Receptor Antagonist, Used in
Opioid-induced Central Respiratory Depression
Doxapram is PCR / CCR Stimulant; Overcomes
Opioid-induced Central Respiratory Depression
Acetazolamide (Carbonic Anhydrase Inhibitor)
causes Acidification of CSF, acting as CCR
Respiratory Stimulant, especially in High Altitude
25. Abnormal Breathing – Apneustic
Description
Prolonged Inspiration
Alternating with short Expiration
(No equivalent Expiration attempt)
Causes
Loss of normal balance between Vagal Input and
the Pons-Medullary Interactions
Lesion usually in Caudal Pons
26. Abnormal Breathing – Biot’s (Cluster)
Description
Several Breaths of identical Rate and Depth
Alternating with irregular periods of Apnea
Causes
Increased ICP
Midbrain Lesions
Serious Head Trauma with Medullary Injury
Brainstem Strokes
27. Abnormal Breathing – Cheyne-Stokes
Description
A type of Periodic Breathing:
60-Second Hyperventilation
followed by Apnea
Cycles of gradually increasing
Depth and Frequency
Followed by gradual decrease
in Depth and Frequency
Between periods of Apnea
Causes
Midbrain Lesions
Head Trauma
Stroke
Infants and During Sleep,
especially High Altitudes
Central (Diaphragmatic)
Sleep Apnea in Elderly
With Type-B ICP Waves in
Normal Pressure Hydrocephal
28. Abnormal Breathing – Ataxic / Agonal
Description
Ataxic Breathing: Irregular breathing
intermixed with irregular periods of Apnea
As breathing continues to deteriorate it becomes
Agonal Respirations, and finally Apnea
Causes
Head Trauma
Medullary Stroke
29. Abnormal Breathing – Kussmaul
Description
Deep, Rapid Breathing to expels excess CO2 in
Metabolic Acidosis
Causes
Diabetic Ketoacidosis (DKA)
CNS Disorders
31. Disclaimer
Neural control of respiration (like neural control of
many other physiological functions, micturition, for
example) is highly complex and not fully elucidated.
Research is still going on to determine the centers in
the brain and their complex interactions.
There may be variations of opinion between different
researchers depending on newer findings.
Every effort has been made to keep this information
as current and authoritative as possible, yet in a
simple enough form for the student to understand
and digest the information.