Gastro intestinal system.(MCQ)

GASTROINTESTINAL SYSTEM (M.C.Q)
TRUE/FALSE (Qs 1-10)

1. All the muscles in the GIT are smooth muscle.
2. After death the length of the intestine is shorter than in vivo.
3. The small intestine can respond to stretch by an increase or a decrease in tension.
4. The entire lining of the small intestine is replaced in 5-6 days.
5. The sympathetic supply of the GIT relaxes the muscularis mucosa.
6. The sympathetic supply blocks the release of mediators from parasympathetic terminals from the myenteric plexus.
7. Mechanoreceptors are found in mucosa, sub mucosa and muscle layers.
8. The oral stage is the only voluntary stage of swallowing.
9. Vagal innervation is essential for the orderly propagation of the primary peristaltic wave along the esophagus.
10. The vomiting center is situated in the hypothalamus.

ANSWERS
1. F (Voluntary muscle is present in esophagus and rectum.)
2. F. 3. T. 4.T. 5. F. 6.T. 7.T. 8.T. 9.T. 10.F. (in the medulla ventral to nucleus of solitary tract.)

(Qs 11-20)
11. Receptive relaxation only occurs in the proximal stomach.
12. Gastric emptying can be either increased or decreased by osmoreceptors in the duodenal mucosa.
13. Segmental movements in the small intestine can occur in completely denervated gut.
14. Peristalsis in the small intestine can be initiated by a myoelectric complex in the antrum/duodenum.
15. Haustral movements are as likely to cause retrograde as orthrograde progression.
16. Aganglionosis of colon (Hirschprung’s disease) causes mega colon.
17. The desire to defecate is related to intrarectal pressure.
18. Normally the secretion of saliva is less than 600 ml/day.
19. Co2 escapes from saliva once it enters the mouth.
20. The parotid glands normally provide most of the salivary volume.

ANSWERS
11. T. 12.T. 13.T. 14.T. 15.T. (Haustrations are due to annular constrictions of circular muscle.)
16. T. 17.T. (Occurs at 20 mmHg; it becomes intense at 50mmHg)
18. F. (1-1.5Litres/day)
19. T. (KHCO3=CO2+KOH) this allows the mouth PH to rise.)

20. F. (Submandibulars provide 70% of salivary volume)

(Qs 21-30)
21. H.pylori infection is nowadays widely accepted as the most common known cause of peptic ulcer.
22. Secretin provokes a very alkaline pancreatic secretion.
23. Only one third of liver bile comes from the hepatocytes.
24. Gall bladder bile is more acid than hepatic bile.
25. Water is reabsorbed by a primary active process from the gall bladder.
26. The normal cholesterol: bilesalts ratio should be less than 1:20
27. Gallstones are most likely to be formed at night or if meals are skipped.
28. G cells are exempt from neural control.
29. Gastrin is important in maintaining gastric mucosal growth.
30. Secretin inhibits gastrin mediated H+ secretion in the stomach.

ANSWERS
21. T. 22. T. 23.T. 24.T. 25.F. 26.T. 27.T. 28.F. (non-cholinergic vagal fibers secrete gastrin releasing peptide)
29. T. 30.T.


(Qs31-40)

31. CCK promotes the concentration of bile in the gall bladder.
32. Aminoacid absorption is virtually unimpaired in a secretory diarrhea.
33. Up to half of the ingested glucose is absorbed in the first 20cm of the jejunum.
34. Absorption only occurs after carbohydrates have been broken down to hexose sugars.
35. Lactose intolerance is due to a failure to absorb the lactose molecule.
36. A chylomicron consists of cholesterol and phospholipid covered in a layer of protein only.
37. Most chloride absorption in the jejunum is by paracellular route.
38. Diarrhea is usually due to problems originating in the large intestine.
39. Serotonin may cause diarrhea by increasing cytoplasmic calcium.
40. The lipostatic theory states that feeding is under the long-term control of total body adipose mass.

ANSWERS
31. F. 32.F. 33.F. (normally all glucose absorption is completed in the proximal jejunum.)
34. F. (pentose sugars are readily absorbed)
35. F. (failure to digest lactose.)
36. F. (also contains triglycerides and often traces lipids)
37. T. 38.F. 39.T. (after over eating bananas-rich in 5-HT.)
40. T(leptin is a protein that regulates body weight and that is encoded in adipocytes).

NEAR-ZERO GRAVITY (MICROGRAVITY)IN SPACE

NEAR-ZERO GRAVITY (MICROGRAVITY) IN SPACE

The human body is an extraordinary but also a complex machine. Like other living organisms, the human body has evolved by adapting to earth’s gravitational field and the biological structure and mechanisms of the body have developed to suit normal earth gravity.
MICRO GRAVITY: The micro gravity environment in space can affect the body in three major ways.
First –there are changes in the blood system.
Second –there is a shift in body fluids towards head.
Third –there is a reduction in weight bearing forces on the body.
Because of these effects, various systems of the body can be affected by space flight. These would include the neurovestibular, cardiovascular, renal/fluid system, musculoskeletal and blood.

INFLUENCE ON BALANCE AND THE SENSE OF ORIENTATION
As stated, the first system to adapt to spaceflight is neurovestibular.This is composed of brain and vestibular apparatus.
In space, balance and orientation are disturbed. The body lacks its normal point of reference.
Function of vestibular apparatus:-on earth
The otolith organs (utricle &saccule) detect change in position of head and help in maintenance of equilibrium under static condition.
*otolith organs also detect linear acceleration of the head and help in maintenance of equilibrium during such movements.
*semicircular canals detect angular acceleration and helps in maintaining the equilibrium during dynamic phase. They also have a predictive function.
*when a person is in dynamic phase ,they predict ahead of time that the person is likely to fall off balance and help nervous system to do adjustments to prevent a fall.
(Vestibular apparatus: - the semicircular canals and the utricle and saccule collectively form the vestibular apparatus and are located in the inner ear.; they play a major role in maintaining posture and equilibrium.)
Mechanism: vestibular apparatus is used to sense movement of head. It is filled with fluid and in the fluid are calcium crystals. When motion occurs, these crystals move and bump into sensory hair cells in the vestibular apparatus, which send signal to the brain. The brain then interprets this signal to determine the direction of movement.
Since there is no gravity in space, the calcium crystals do not move in a manner similar to that on earth.
Even after the astronaut leaves earth, the brain continues to believe that its point of reference is terrestrial ones. Since this information is chaotic, astronaut has trouble adapting to this new microgravity environment and disoriented. Because the sensors in the ear and muscular apparatus cannot orient themselves in zero gravity environment. The only useful information reaching the astronauts brain is through the eyes.
In space, astronauts must take some time to lose the disoriented feelings associated with weightlessness; because of lack of gravity, the otolith organs no longer play the same role; they can sense linear acceleration, but cannot establish a vertical reference signals to the brain. Adaptation to this new environment involves learning to use nonvestibular signals that are visual, proprioceptive and tactile.
INFLUENCE ON BLOOD CIRCULATION:
One of the most visible effects of a space mission is no doubt the puffy-face, bird-leg look that astronauts get. On earth, heart is programmed to distribute blood evenly throughout the body. The heart must do more work to supply the upper body, because the force of gravity naturally draws blood downward. The lower limb does not have this problem, as the blood coming to them is gravity assisted.

In space, bodily fluids no longer flow back down naturally by gravity. The heart is still programmed the way it was on earth.so, under the pressure of the heart and the veins and an artery the blood rushes to the person’s torso, head, and results in puffy face. The veins of the neck and face stand out more than usual, the eyes become red &swollen, and legs are thinner because instead of dropping effortlessly down to the lower limbs, the blood has to be pumped there by the heart. Because of these physiological changes, astronauts suffer from space sickness.

INFLUENCE ON BONE AND MUSCLE:
In space, the musculoskeletal system continuously deteriorates. Leg muscles in particular, which are underused, become flabby and loose, tone and mass. Muscular atrophy occurs. The bones, too become weaker bcz of a loss of minerals (Ca, K, Na)

Did you know that your body gets taller in space?
Because the spine is no longer compressed by gravity, the vertebra separates slightly from one another and the body lengthens.

PHSIOLOGICAL EFFECTS OF SPACE FLIGHT:
Space sickness, disorientation, migration of organic fluids to the upper body, bone deterioration, muscular atrophy, lenghthening of spine, backache etc.

WONDERS OF HUMAN BODY

THE WONDERS OF HUMAN BODY
*There are about 96,000 km of blood vessels in our body.
*Man breaths 13-17 times /mt.on an average 21,600 times /day.
*Alimentary system is a 9.14-meter long tube. Small intestine is 6.096-meter length.
*Total number of bones in our body-206
.longest bone –femur/thigh bone
.smallest bone –stapes in the ear
*In the human body there are 639 muscles, which also account for 40% of the total body
Weight.
*The fastest nerve impulse travels at 532 kmph.
*Humans can detect 10,000 colors, 500 different tastes and 1500 different tones.
*Stomach produces 2 liters of Hcl acid/day.
*The brain: the 1.36kg organ stores 100 trillion bits of information over the course of 70 years, equal to 500,000 sets of the encyclopedia.
.It can work better than any computer.
.Neurons is the longest cells in our body.
*Largest organ in the body: The skin
*Organs that you can do without:-Tonsils and appendix.
*Body’s instant energy provider: The liver.

STRESS and DESTRESS

STRESS and DESTRESS
Stress! It’s as inevitable as death &taxes, and it has more disguises than you can imagine, including frustration,anxiety,fear,job and family pressure, sadness and happiness, and boredom and overactivity.Stress is a normal part of life; it’s how you respond to it that affects your health.
Lifestyle, personality&even genetic makeup influence our emotional and physiological responses to stress. However, you can modify those responses by making changes in how we act, think, relate, move&relax.
Be more flexible.
Take things one at a time.
Learn to say no &avoid taking on more responsibility than you can handle. Cut out unnecessary activities.
Rest rejuvenate-even during busy periods; try to leave work at a reasonable time a few nights a week, also every hour take a five mts break&walkaround.
Keep in touch-the more social contact you have the less stressed you feel lowered your risk for many illness.
Workout, jog or walk-exercise is one of the best antidotes to stress.
RESISTANCE TO STRESS
The term stress as used in biology has been defined as any change in the environment those changes or threatens to change an existing optimal steady state. Most if not all of these stresses activate counteractions at the molecular, cellular, or systemic level that tend to restore the previous state, ie, they are homeostatic reactions. Some but not all of the stresses stimulate ACTH .This ACTH secretion is essential for survival when the stress is severe.
PSYCHONEUROIMMUNOLOGY
Mind influences the body in a profound manner through neuroendocrine mechanism. The bodily changes induced by emotions include not only those on the heart, blood vessels, respiration and gut but also on the immune system. Positive emotions such as love &joy enhance immunity, whereas negative emotions such as anger and depression impair immune function. The effects on immunity have been measured in terms of natural killer cell activity, proliferation response of lymphocytes to mitogens and antibody titer.
AN INTEGRATED RESPONSE TO STRESS
Stress, may it be emotional, physical or biological evokes an integrated response of sympathoadrenal medullary system and hypothalamic-pituitary cortex axis.
STEPS INVOLVED IN STRESS ADAPTATION
PERCEPTION OF STRESS SIGNALS: Stress is perceived by many areas of the brain, from the cortex down to brainstem including limbic system and reticular activating system (RAS)
ACTIVATION OF HYPOTHALAMIC-PITUITARY-ADRENAL AXIS.Major stresses activate CRH neurons, CRH release stimulates ACTH release and ultimately elevates plasma cortisol levels.
ACTIVATION OF SYMPATHOADRENAL MEDULLARY SYSTEM:
“ALARM” OR STRESS RESPONSE OF THE SYMPATHETIC NERVOUS SYSTEM
When large portions of sympathetic nervous system discharge at the same time-that is, a MASS DISCHARGE –this increases in many ways the ability of the body to perform vigorous muscle activity. The effects are:
1. Increased arterial pressure.
2. Increased blood flow to active muscles with decreased blood flow to organs such as GIT&KIDNEYS.
3. Increased blood glucose concentration.
4. Increased glycolysis in the liver&in muscle
5. Increased muscle strength
6. Increased mental activity.
The sum of these effects permits a person to perform far more strenuous physical activity than would otherwise be possible. The purpose of the sympathetic system is to provide extra activation of the body in states of stress; this is called the sympathetic stress response.
IMPLICATIONS FOR DISEASE
Stress may progress the development of type1 diabetes by stimulating the secretion of counter-regulating hormones &possibly by modulating immune activity.
Acute stress reactions:
Following stressful event, some people develop a characteristic pattern of symptoms, which include anxiety, anger, depression, overactivity&withdrawal.The symptoms are transient; they start to subside within a few hours and usually completely resolve within 3 days of their onset. Precipitating events include a traumatic diagnosis such as that of AIDS or CANCER, death of a family member, a major accident, assault and rape.
The autonomic responses to emotions are appropriate for physical activity, and thereby make the body for fight or flight associated with stressful situations. In human beings, civilized behavior demands that physical activity be avoided, no matter how much the provocation. The results are increased cardiac output and constricted blood vessels, which leads to a steep increase in blood pressure and an enormous increase in the workload of the heart. In acute stress, these changes are reversed, but in chronic stress, the elevation in blood pressure becomes persistent leading to hypertension.
Most of the stressful stimuli that increase ACTH secretion also activate the sympathetic system, and part of the function of circulating glucocorticoids may be maintenance of vascular reactivity to catecholamines.It should be noted that the increase in ACTH which is beneficial in the short term, becomes harmful and disruptive in the long term, causing among other things, the abnormalities of Cushing’s syndrome.
A QUICK STRESS TEST
Do you:
*Neglect your diet?
*Try to do everything yourself?
*Act rude?
*Make a big deal of everything?
*Fail to laugh at what others find funny?
*Avoid people whose ideas differ from yours?
*Neglect exercise?
*Get too little rest?
*Get angry when kept waiting?
*Gossip?
*Spend a lot of time complaining about the past?
*Use sleeping pills without your doctor’s approval?
If you answer yes to more of the questions, you need to reduce stress in your life.
RELAXATION TECHNIQUES:
*BREATHE DEEP: Inhale slowly and deeply as you expand first the belly, then the diaphragm and finally the chest. Hold for a few seconds, and then exhale in a reverse 1-2-3 pattern. Repeat 10 times.
*STRETCH: 10 mts day of simple stretching or yoga can keep tense or underused muscles loose, help prevent future tension, and recharge your batteries.
MEDIDATE: Calm, inward reflection for only 10to 20 mts a day may help lower blood pressure. Sit or lie down in a quiet, comfortable place. A nice view, fresh air, soft music, or sweet scents can help clear your mind.

Always have a positive attitude in life.
There is something positive in every person,
Even a stopped watch is right twice a day.
Happiness always looks small,
When we hold it in our hands
However, when we learn to share it,
We realize how big and precious it is…!

“Winners don’t do different things
They do things differently.”(_shiv khera)

Think different….think apple

CENTRAL NERVOUS SYSTEM

TRUE/FALSE in C.N.S
1.cerebral blood flow:(CBF)

a).is subject to autoregulation over a mean arterial pressure (MAP) range of 50-150 mmHg
b)is critical for maintaining the intracranial pressure(ICP) at around a normal of 10-15mmHg.
c)is adjusted to keep a cerebral perfusion pressure(CPP) of about 70mmHg in normal people.
d)hypoxia is a more potent stimulus for increased CBF than a similar fall in the PaCO2.
e)overall CBF and oxygen consumption in the brain varies widely throughout a normal 24 hours.
f)sympathetic vasoconstriction of cerebral vessels is often seen in acute brain damage.

g)cerebral steal means that blood is diverted to the brain from extra cranial regions.

h)increases during sleep.

2.The intracranial pressure (ICP)
a)increases during sleep(irrespective of position)

b)almost all volatile anaesthetics increase the ICP.

3.Cerebral cortex,EEG,CVA
a) the EEG is due to firing of cortical neurons (AP generations)

b)in an alert adult with closed eyes,alpha waves predominates

c)irregular small waves are characteristic of mental activity

d)during seizures the brain ECF K+ often rises dramatically.

e)a transient ischaemic attack( TIA) usually lasts less than 10 mts.

The thalamus:
f)plays an essential role in arousal.

g)has each half of the body represented topographically.

4.subcortical areas
Regarding reticular formationRF and limbic system

a)the only proven function of RF are associated with wakefulness,arousal,and posture control.

b)the amygdaloid nucleus is mainly concerned with memory

c)the hippocampus is important in behavioural disorders

d)some striatalnigral fibres release serotonin

e)some nigrostriatal fibres secrete acetylcholine

f)the tremor in parkinsonism PD is exacerbated by alcohol

g)the tremor in PD is present even when the subject is asleep

h)GABA agonists worsen parkinsonism

5.pain
a)pain receptors are polymodal in nature

b)anaesthetization of stump gives only temporary relief in phantom pain

c)pain pathways are not fully developed in the newborn

6.memory
a)working memory is located mainly in the frontal lobes

b)one cannot transfer information from primary to secondary memory in anterograde amnesia.

7.Sleep

a)in REMsleep there is a general rise in skeletal muscle tone

b)REM generating neurons lie in the pons

c)normally REMsleep occurs within 10 min of falling sleep

d)at birth REM accounts for about 50% of sleep

e)sleep-walking occurs in deep stage 3-4 NREM sleep

f)hypnic jerks,bruxism(teeth grinding)and head-banging occur in REM sleep

g)daytime sleepiness,per-sleep dreams,sleep paralysis,cataplexy confirm the diagnosis of narcolepsy.

h)obstructive sleep apnea and obesity often go together

i)polycythemia is common in subjects who suffer from sleep apnea

j)the sleep-wake cycle is retained in coma


TRUE/FALSE in CNS (ANSWERS)
1.a)true b)true c)true d)false.(the PaCO2 must fall below 50 mmHg before there is a significant rise in the CBF.)
e)false.(CBF and o2 consumption are fairly constant over a period of 24 hrs(3ml/100gm/mt)
f)true g)false( diversion of blood to an area of the brain that is relatively vasodilated from other normally perfused areas of the brain)
h)true
ed
2.a)true b)true

3.a)false (EEG is due to changes in EPSP and IPSP in cortical neurons.)
b)true c)true d)true e)true f)false(arousal is possible even if the thalamus is grossly damaged
g)true

4.a)false(RF also modulates muscle tone ,maintains vegetative functions and has a role in affective emotions(pain,pleasure,aggression )
b)false(aggression ,restlessness,and instinctual drives)
c)false(short term memory)
d)false(some nigrostriatal fibers release serotonin)
e)true
f)false(lessened by alcohol)
g)false(disappears in sleep)
h)true

5.a)true b)false(central in origin.,gives no relief)
c)false(pain receptors have been demonstrated from 7th week of fetus.thalamocortical connections are complete by 20-24 weeks of gestations)

6.a)true b)true

7)a)false(atonia)
b)true c)false(begins about 40 mts after sleep onset)
d)true e) true f)false(occurs in stage 1-2 of NREM sleep
g)true h) true i) true j) false(however it is retained in persistent vegetative states)

THE HOLY GRAIL OF GENERAL INTELLIGENCE

THE HOLY GRAIL OF GENERAL INTELLIGENCE

DNA : ENVIRONMENT
50 : 50

Exactly what is human intelligence & how should we measure it?
Intelligence is a very difficult concept to define, it is described as the "power of the mind to think in a logical manner & acquire knowledge."

Is intelligence inherited? It is generally accepted that intelligence is inherited but can also be related to the environment.

Genetic control: A degree of intelligence is written in the genes & determined before birth. It suggests that the ability to do well in the intelligence tests is linked with the amount of grey matter in the brain, something that depends largely on genes. Studies showed that the grey matter volume is strongly determined by genes and reflected cognitive performance. It was also suggested that there is a strong genetic influence on IQ , so our genes determine the quality of our intelligence, our ability to integrate & process the information. The level of our intelligence determines how well we cope with changes in our environment. The genetic brain maps reveal a strong relationship among: genes, brain structure & behaviour, suggesting that highly heritable aspects of brain structure may be fundamental in determining individual differences in cognition.

Biological basis: Scientists have long suspected that grey matter is the seat of intelligence in the brain. Finally a correlation between: grey matter density & general cognitive ability provides evidence for a biological basis for it (IQ). A component of our problem solving ability is inherited, but its only very minimal of the variation in that trait, which means to say that the effects of nurture of learning-the non genetic factors, have tremendous importance in building brain structure, intelligence & performance in tests.

Your brain, your nervous system - your entire body is constructed according to instructions received from the genes that you have inherited from your parents. However, the ability to speak a certain language is not inherited, but is dependent on the language that the child hears on a daily basis! In the same way, intelligence might be dependent on the child's environment & specifically the quality & quantity of education that one receives. Whether nature or nurture influences intelligence remains a matter of debate between: geneticists & environmentalists & sits at about 50/50.

CAN WE INCREASE OUR INTELLIGENCE?

There are certainly ways to increase one's intelligence also called, intelligence amplification/enhancing, by practicing many proven cognitive tools such as mnemonics, problem solving techniques, creative techniques etc.

Some intelligence boosters are listed below -

Good reasoning is the key to success-if performed in the proper order.

1. have an objective
2. make a general sensing about it
3. determine your decision
4. make alternate plan
5. select the best plan
6. start by carrying out your plan
7. observe results
8. store experience.
(You cannot learn swimming from a book & you cannot learn to think without practicing)

NEW BRAIN CELLS?

It is now established that the traditional view that the brain cells are not added after birth is wrong. New neurons form from stem cells throughout life in two areas - the olfactory bulb & hippocampus. Since the hippocampus is concerned with memory, the memories could be related to new brain cells. During the first few weeks, months perhaps even year or so of life, many parts of the brain produce a great excess of neurons & the neurons send out numerous axon branches to make connections with other neurons. If the new fails to connect with appropriate subsequent neurons, muscle cells or gland cells, the new axon themselves will dissolute within a few weeks. The number of neural connections is determined by specific nerve growth factors released retrogradely from the stimulated cells. Furthermore when insufficient connectivity occurs, the entire neuron that is sending out the axon branches might eventually disappear.

Physiologically memories are stored in the brain by changing the basic sensitivity of synaptic transmission between: neurons, as a result of previous neural activity. The new or facilitated pathways are called memory traces in the cerebral cortex. Electron microscopic pictures have demonstrated multiple structural changes in many synapses during development of long-term memory traces. The most important structural changes are:

1.increase in no. of transmitter vesicle
2.increase in vesicle release sites for secretion of transmitter substance
3.increase in no. of presynaptic terminals

CONCLUSION

Human being is not merely a slave to his genes. Human life can be compared to a game of cards. At birth, every person is dealt a hand of cards-his genetic make-up. Some receive a good hand, others a less good one. Success in any game, however is almost always a matter of erudition. It is undeniably, there are innate qualities that will give one person an advantage over other in a specific game. However without having learnt the game, and without regular & rigorous practice, nobody will ever become a champion at any game. In the same way, the life is not determined by the quality of a persons initial hand of cards (genetic make-up), but also by the way in which he takes part in the game of life. It will be determined to a very large extent by the child's environment & specifically the quality & quantity of education that he has enjoyed.
(Published by dr.r.vinodha in APTCON 09-3rd Annual state conference)

LORD SHIVA'S 3RD EYE (the eye of wisdom)Vs HUMAN 3RD EYE (the pineal gland)

LORD SHIVA'S 3RD EYE-(THE EYE OF WISDOM0 Vs THE HUMAN 3RD EYE-(THE PINEAL GLAND)


Shiva is one of the gods of trinity.Lord shiva also called "THREE EYED LORD"is depicted as having 3 eyes,the sun is his right eye ,the moon the left eye,&fire the third eye.The 2 eyes on the right&left indicate his activity in the physical world.The third eye in the center of the forehead symbolizes spiritual knowledge&power&thus called the eye of wisdom or knowledge -the symbol of higher consciousness.
Like fire,the powerful gaze of shiva's 3rd eye annihilates evil& thus evil doers fear his 3rd eye.The very important physical characteristic of shiva is his vertical eye -the 3rd eye.
HUMAN THIRD EYE-THE PINEAL GLAND
-is a small endocrinegland in the brain.It is believed by Rene Descartes to be the seat of the soul.(who dedicated much time to the study of pineal gland.The gland weighs little more than0.1gm &larger in children & begins to shrink with the onset of puberty.In adult human ,small concretion of capo4&caco3(pineal sand)appear in the tissue.they are radio opaque,the normal pineal is often visible on xray films of the skullin adults.displacement of calcified pineal from its normal position indicates the presence of S.O.L such as brain tumour.

It is believed to be a dormant organ that can be awakened to enable telepathic communication.The pineal gland is occassionally associated with 3rd eye chakra in yoga.The pineal gland contains a complete map of the visual field of the eyes.There is a pathway from retina to hypothalamus (SCN-suprachiasmatic nuclei)called retinohypothalamic tract.It brings information about light&dark cycle to SCN.From SCN impulses travel via sym.n to pinealgland.These impulses inhibit the production of melanin from the pineal gland.When these impulses stop (at night,which light no longer stimulates the HT,pineal inhibition ceases &melatonin released.Melatonin may function as a timing device to keep internal events synchronized with light-dark cycle in the environment.

Visualization exercises are the 1st step in directing the energies in our inner system to activate the 3rd EYE.THE 3RD EYE OF SHIVA-The organ of spiritual vision ,is intimately related to karma ,as you become more spiritual in natural course of evolution,the pineal gland will continue to rise from its age-long dormant state to active state&will bring back the human astral capacities and spiritual abilities.