Search This Blog

ANS innervation...
























ANS
The autonomic nervous system (ANS or visceral nervous system) is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness, and controls visceral functions.The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils, micturition (urination), and sexual arousal. Whereas most of its actions are involuntary, some, such as breathing, work in tandem with the conscious mind.
It is classically divided into two subsystems: the parasympathetic nervous system and sympathetic nervous system.Relatively recently, a third subsystem of neurones that have been named 'non-adrenergic and non-cholinergic' neurones (because they use nitric oxide as a neurotransmitter) have been described and found to be integral in autonomic function, particularly in the gut and the lungs.
With regard to function, the ANS is usually divided into sensory (afferent) and motor (efferent) subsystems. Within these systems, however, there are inhibitory and excitatory synapses between neurones.
The enteric nervous system is sometimes considered part of the autonomic nervous system, and sometimes considered an independent system.





Function:Sympathetic and parasympathetic divisions typically function in opposition to each other. But this opposition is better termed complementary in nature rather than antagonistic. For an analogy, one may think of the sympathetic division as the accelerator and the parasympathetic division as the brake. The sympathetic division typically functions in actions requiring quick responses. The parasympathetic division functions with actions that do not require immediate reaction. Consider sympathetic as "fight or flight" and parasympathetic as "rest and digest".
However, many instances of sympathetic and parasympathetic activity cannot be ascribed to "fight" or "rest" situations. For example, standing up from a reclining or sitting position would entail an unsustainable drop in blood pressure if not for a compensatory increase in the arterial sympathetic tonus. Another example is the constant, second to second modulation of heart rate by sympathetic and parasympathetic influences, as a function of the respiratory cycles. More generally, these two systems should be seen as permanently modulating vital functions, in usually antagonistic fashion, to achieve homeostasis. Some typical actions of the sympathetic and parasympathetic systems are listed below.

Sympathetic nervous system
Promotes a "fight or flight" response, corresponds with arousal and energy generation, and inhibits digestion.
Diverts blood flow away from the gastro-intestinal (GI) tract and skin via vasoconstriction.
Blood flow to skeletal muscles and the lungs is not only maintained, but enhanced (by as much as 1200% in the case of skeletal muscles).
Dilates bronchioles of the lung, which allows for greater alveolar oxygen exchange.
Increases heart rate and the contractility of cardiac cells (myocytes), thereby providing a mechanism for the enhanced blood flow to skeletal muscles.
Dilates pupils and relaxes the lens, allowing more light to enter the eye.
Provides vasodilation for the coronary vessels of the heart.
Inhibits peristalsis.

Parasympathetic nervous system
Promotes a "rest and digest" response, promotes calming of the nerves return to regular function, and enhances digestion.
Dilates blood vessels leading to the GI tract, increasing blood flow. This is important following the consumption of food, due to the greater metabolic demands placed on the body by the gut.
The parasympathetic nervous system can also constrict the bronchiolar diameter when the need for oxygen has diminished.
Dedicated cardiac branches of the Vagus and thoracic Spinal Accessory nerves impart Parasympathetic control of the Heart or Myocardium.
During accommodation, the parasympathetic nervous system causes constriction of the pupil and lens.
The parasympathetic nervous system stimulates salivary gland secretion, and accelerates peristalsis, so, in keeping with the rest and digest functions, appropriate PNS activity mediates digestion of food and indirectly, the absorption of nutrients.
Is also involved in erection of genitals, via the pelvic splanchnic nerves 2–4.



Special regards by

Dr.M M ADNAN
contact id:adnan_dani12@yahoo.com

4 comments:



  1. mbbs in Philippines
    Every year, almost 8000 foreign students take admission in Philippines Medical universities and out of which around 50% are Indian students. The standard of education in Philippines universities is well known around the world. Thousands of doctors from these medical universities are sent to various countries like USA and UK every year. There are around 2299 higher educational institutions and 40 medical colleges. The main benefits of pursuing MD degree from

    Top Medical Colleges in Philippines :

    EMILIO AGUINALDO COLLEGE OF MEDICINE
    UNIVERSITY OF PERPETUAL HELP SYSTEM DALTA
    LYCEUM NORTHWESTERN UNIVERSITY
    DAVAO MEDICAL SCHOOL FOUNDATION
    SOUTHWESTERN UNIVERSITY

    Top Searched Topics on MBBS in Philippines


    study mbbs in philippines
    philippines medical colleges list
    best medical colleges in philippines for indian students
    philippines medical colleges
    best medical colleges in philippines
    mci approved medical colleges in philippines

    for more information contact us : +91 90329 55688

    ReplyDelete
  2. The Davao Medical School Foundation Inc. (DMSFI) was established in July 1976 in response to the recognition of the lack of doctors serving rural communities and lack of specialist in urban centres of Mindanao. Its College of Medicine was thus the first such college to be set up in Mindanao and is dedicated to providing medical education and training of the highest order, leading to the provision of effective medical care in both rural and urban communities.

    ReplyDelete

  3. Southwestern University is probably the only school in the Philippines that started operation in summer. It was founded as Southwestern Colleges in the summer of 1946 when the country was still reeling from the destruction of the Second World War. The Founders were Don Matias Hipolito Chavez Aznar, II and his wife Doña Anunciacion Barcenilla Aznar, both pharmacists.

    ReplyDelete
  4. Emilio Aguinaldo College Of Medicine is best medical college in Philippines.
    Best Option to Study mbbs in EAC for Indian Students
    Emilio Aguinaldo College (EAC) was founded in 1951 under the name of Marian School of Midwifery. The Emilio Aguinaldo College of Medicine was established on July 23, 2001, and it has two campuses in Manila city and greater Manila. It is approved by the Commission of Higher Education (CHED) Philippines.

    University of Perpetual Help System Dalta Top Medical College in Philippines
    University of Perpetual Help System Dalta (UPHSD), is a co-education Institution of higher learning located in Las Pinas City, Metro Manila, Philippines. founded in 1975 by Dr. (Brigadier) Antonio Tamayo, Dr. Daisy Tamayo, and Ernesto Crisostomo as Perpetual Help College of Rizal (PHCR). Las Pinas near Metro Manila is the main campus. It has nine campuses offering over 70 courses in 20 colleges.


    The Davao Medical School Foundation, Inc. (DMSFI) was established in July 1976 in response to the recognition of the lack of doctors serving rural communities and lack of specialist in urban centers of Mindanao. Its College of Medicine was thus the first such college to be set up in Mindanao and is dedicated to providing medical education and training of the highest order, leading to the provision of effective medical care in both rural and urban communities.

    ReplyDelete