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Masticatory Reflexes or Jaw Reflexes

Varun — Mon, 26 Dec 2011 20:19:20 +0000

Reflex is a highly stereotyped automated response to a specific stimulus

Masticatory reflexes are type of stretch reflexes brought about by activation of muscle spindles in the muscles

Types of Jaw Reflexes:

Jaw Closing Reflex / Jaw Jerk Reflex
Jaw Opening Reflex
Jaw Unloading Reflex
Tooth Contact Reflexes
Horizontal Jaw Reflexes

Jaw Closing Reflex / Jaw Jerk Reflex:

A stretch reflex similar to knee jerk reflex
It is a monosynaptic reflex generated by stretching muscle spindles in the masseter muscle
Latency period 7-12ms
Demonstration: A sharp downward tap on the chin when the mandible is held loosely in the rest position results in contraction of the masseter muscle to bring the teeth into occlusion

Jaw Opening Reflex:

Polysynaptic reflex
Occurs as a result of mechanical or electrical stimulation of the lips, oral mucosa or teeth
A slight opening movement occurs due to inhibition of activity in the mandibular elevators without simultaneous contraction of the depressors

Jaw Unloading Reflex:

It is a protective reflex that occurs when the jaw is suddenly unloaded
Eg: When a stone comes inside mouth with food while mastication.
On sudden encounter with the hard object, mastication is stopped.
This is due to reflex inhibition of elevators & reflex excitement of jaw depressors
Due to receptors in periodontal ligament
Protects teeth from damage

Tooth Contact Reflex:

Reflex changes that occur in the elevator muscles when the upper & lower teeth are snapped together
There is transient activation followed by a silent period & then a phase of increased & decreased activity in the elevators
No effects on the depressors

Horizontal Jaw Reflexes:

Lateral, protrusive & retrusive reflex mandibular reflexes

Swine Flu Symptoms in Animated way

Varun — Wed, 09 Sep 2009 12:14:17 +0000

Swine Flu which is spreading havoc around the world is being neglected or is been overlooked by lack of knowledge about the symptoms.
The lack of knowlegde and the lack of resources to Diagnose the disease is making it more and more prevalent around the world.

The Symptoms are :

Cough and Cold
Chills
Fatigue
Sore Throat
Nausea
Vomitings
Diarrhoea

Is AIDS Finally Conquered | Is AIDS Cure on the Way

Varun — Mon, 22 Jun 2009 06:35:43 +0000

AIDS the most dreaded disease in the world without any cure is being studied extensively all around the world as due to AIDS there are many diseases which are surfacing due to the decrease in immunity such as Tuberculosis, which was brought under control and thanks to AIDS it is again becoming very harmful to human kind.

So in a Breakthrough in the medical world some scientists from Canada have finally found where the HIV virus hides in the human body making them impervious to medical treatment.

This discovery could well make way for the invention of a complete cure to this dreaded disease.

Where does it actually hide in the Body making it impervious to treament ?
Professor Rafick-Pierre Sekaly, researchers said they have found that the virus hides in “long-lived” memory cells in the human body.
These memory cells, which have a long life just like the stem cells, lie sleepy in the body most of the time until they encounter a new virus or disease-causing agents.

Why is it Dangerous, when they stay in Memory cells ?
Like stem cells, these memory cells are also capable of replicating themselves. So when the AIDS enters them or attacks them, these memory cells multiply to defend the body.
But the problem is that the once AIDS virus enters these memory cells, it also multiplies with them.

Is the Current Medication given helping the Patients from the Virus ?
Thus, ruring the current intense medication – which involves five to six drugs that can prolong life up to 13 years – for a patient, the AIDS virus retreats into these safe havens to stage an attack later.

How do the researchers plan to kill the virus without erasing our memory by killing our memory cells ?

The researchers said they are still finding ways to destroy the virus in its safe havens in the memory cells without harming the immune system.

Their research is the “first clue” to eliminating the AIDS virus, said research leader Sekaly on Sunday.

Mastication

Varun — Mon, 18 Aug 2008 10:22:24 +0000

Definition:

Rhythmic opposition & separation of jaws with the involvement of teeth, lips, cheeks & tongue for chewing of food in order to prepare it for swallowing & digestion.

Mastication is also called as Chewing in common words.

Various parts involved:

Teeth
Tongue
Palate
Lips / Cheeks

Functions Of Mastication:

Increases surface area for action of enzymes
Stimulates mucosal circulation & keratinisation of mucosa
Increases thickness of periodontal ligament
Stimulates alveolar bone growth

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