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.

TELEPATHY? OR MERE COINCIDENCE?

TELEPATHY OR COINCIDENCE?
ESP:Extra sensory perception was coined by J.B Rhine to denote pa rapsychological abilities such as telepathy,precognition,&clairvoyance.It is sometimes casually referred to as a sixth sense.This direct mind to mind communication is often said to be instantaneous &independent of distance.
ESP fall into 4 general categories-
.TELEPATHY-a person's awareness of another's thoughts without any communication thro normal sensory channel.
.CLAIRVOYANCE-knowledge acquired of an object or event without the use of senses.
.PRECOGNITION- a person may have another persons future thoughts or of events.
.PSYCHOKINESIS-a persons ability to influence a physical object or an event by merely thinking about it.
TELEPATHY
MIND TO MIND COMMUNICATION-Apparent ability to send and receive thought's and other mental data directly from one mind to another.
Telepathy or coincidence??
who possesses ESP?
Every person?!!
The fact that some have developed this ability to a very high degree,has created the impression that only certain people have ESP,many of them have had atleast one spontaneous ESPexperience/(coincidence)in their life.
It's happened to you.for some reason you thought about a person you know pop into your head,
The phone rings,
Amazingly, it's that very same person you where thinking!!
OR
you are driving in a car &humming a song...
You turn on the radio ...
The same song is playing!!
MECHANISM
There is no clear explanation.most of the mechanism remain controvercial.so, we can let our imagination run wild &suggest the following possible mechanism.
How&why does the brain communicate with another brain?
Apparently you have a part of a brain that is tunable to all mind frequencies.this part also has' memory' for" mind frequencies"of certain known pepple.(friends&relatives)this brain component is called the "scanner".(It would be assumed that such a" radio "like waves would be an electromagnetic nature)
An alert signal is sent to a person' own scanner when he is under some forms of extreme emotional distress,Any other scanner tuned to this scanner will pickup on this &rest of the brain will tune itself to the activated frequency.The "receiver scanner"had been always tuned in to the "transmitter scanner"
Neuronal circuit:
Intense activities of limbic system has been reported in mind to mind communication&chronic hyperstimulation of limbic lobe can induce some individuals to become hyperreligiousor visualize&experience ghosts,angelsor even GOD or the sensation of having left thier body.
CONCLUSION
Do you believe the mechanism of working of telepathic organ?
If you believe mind to mind interaction;
Why not heart to heart interaction?!!

EFFECT OF BODY POSITION (SUPINE,RLD,LLD)ON VENTILATION&GAS EXCHANGE IN UNILATERAL PULMONARY DISEASE.

EFFECT OF BODY POSITION (SUPINE,RLD,LLD)
ON VENTILATION AND GAS EXCHANGE IN
UNILATERAL PULMONARY DISEASE.
( Presented by Dr.R.Vinodha,M.D.,in Indian Assosiation of Biomedical Scientists
XIV annual conference)

Abstract
In normal subjects breathing normally both blood flow and ventilation are greater in dependent lung zones.These considerations may assume clinical importance in unilateral pulmonary disease.This study was undertaken to verify this in patients,thoracic medicine dept, M.M.C.,Chennai.A.B.G Analysis,&ventilatory tests(VC,FEVC,FEV1)Were measured after 15 minutes in each of the 3 positions.(supine,RLD-right lateral decubitus&LLD-left lateral decubitus)This study indicates that body position can influence gas exchange in patients with unilateral lung disease.lying with the disease lung dependent ,resulted in the lowest arterial o2 pressure and worst gas exchange;lying on the good lung resulted in maximal arterial pressure and better gas exchange.The clinical implication of these data are that study of positionally modulated gas exchange in patients with pulmonary disorders can provide potentially useful clinical information as well as test some of the thereotic concepts of gas exchange.Morover the finding of a significant difference in pao2 going from one lateral decubitus position to the other, suggest that lateral positioning of pulmonary patients is not without significant consequence to gas exchange and might advantageously be used in the therapeautic programme.
(fig:1.Radiographic appearance of destroyed lung cavity with fibrosis.
fig:2.Lobectomy.
fig:3.Pneumonectomy.)

RESPIRATORY SYSTEM:MCQS

RESPIRATORY SYSTEM
MCQS

TRUE OR FALSE


1.In inspiration
a.The abdomen moves outwards.
b.The costal margin moves outwards and upwards.
c.Centralvenous pressure increases.
d.Airways resistance is less than during expiration.
e.Intrapleural pressure is sub-atmospheric.

2.Surfactant:
a.Produces a greater lowering of surface tension in small bubbles than in large bubbles.
b.Activity in a surface is enhanced by transient increase in area or radius of curvature of the surface.
c.Is present in foetallungs from the 20th week of gestation.
d.Production is dependent upon pulmonary perfusion.

3.The closing volume of the lungs( CV )
a.is the volume of air expired before airways close off.
b.is small (20-50ml)during quiet expiratiopn in normal individual.
c.is associated with the closure of airways in the apex of the lung before closure elswhere.
d.increses in recumbency.
e.if it equals the tidalvolume,is incompatible with life.

4.In the mechanics of breathing:
a.the compliance is given by volume/pressure.
b.the compliance of the lung is about the same as that of the thoracic cage in young healthy adults.
c.the compliance of the thorax decreases in obesity.
d.the volume change lags begind the pressure change in both inflation and deflation of the lungs.
e.an estimate of elastic forces is given by area between inspiratory and expiratory traces on hysterresis loop.

5.Airway resistance:
a.is a major factor in the elastic resistance of the lungs.
b.is mainly determined by the calibre of the airways.
c.falls at high altitude
d.is inversely related to FEV1
e.increses as lung volume increases.

RESPIRATORY SYSTEM:ANS
1.a.True
b.True
c.False
d.True
e.True

2.a.True
b.True
c.False
d.True.

3.a.false
b.false
c.false
d.true
e.false

4.a.false
b.true
c.true
d.true
e.false

5.a.false
b.true
c.true
d.true
e.false

RESPIRATORY SYSTEM:MCQS

RESPIRATORY SYSTEM
MCQS

TRUE OR FALSE
1.During normal quiet tidal breathing:
a.the dome of the diaphragm hardly moves at all.
b.the upper external intercostal musles help aerate the bases of the lungs.
c.paralysis of the external intercostal muscle reduces the tidalvolume by about 10%
d.there is a decrese in both intrapleuralpressure and intraalveolarpressure during the inspiratory phase.
e.the actual amountof air shifted eachtime by an adult is about 250 ml.

2.Concering volumes &capacities
a.a capacity is 2 or more volumes added together.
b.vital capacity (VC) can be used to monitor heart failure.
c.the VC falls significantly on recumbency in normal people.
d.VC is a good screening test of lung function.
e.the residual volume is exaled in maximal expiration.

3.the functional residual capacity (FRC)
a.is related in a linear fashion to one's height.
b.falls markedly as one gets older.
c.is increased in emphysema.
d.rises in recumbency.
e.should normally be about 40% of the total lung capacity.

4.In the alveoli:
a.type 1 pneumocytes form the major part of the surface.
b.type 2 pneumocytes produce surfactant.
c.type 3 pneumocytes contain concentric lamellated bodies.
d.gas flow is highly turbulent.
e.macrophages are usually present.

5.In normal lungs
a.in the upright posture ventilation is greater at the apex than at the base.
b.in the upright posture ventilation:perfusion ratio increases from base to apex.
c.residual volume is less than 35% of total lung capacity.
d.airways resistance falls during expiration.

6.Arterial pco2:
a.can be measured directly using an electrode.
b.can be calculated from measurements of PH of arterial blood when fresh and after eqilibration to varying blevels of pco2 in a tonometer.
c.can be estimated by analysis of end expired air.
d.is directly propotional to alveolar ventilation under steady state conditions. RESPIRATORY SYSTEM
MCQS

TRUE OR FALSE
ANSWERS

1.a.false.(diaphragm moves about 1cm during quiet breathing & about 10 cm during hyperventilation.
b.true
c.false.(bcz diaphragm is so effective.)
d.true.
e.false.(tidal vol is 500ml)

2.a.true
b.true
c.true
d.false(vc depends on chest compliance ,muscle power,&body size)
e.false.

3.a.true
b.false
c.true
d.false.
e.true.

4.a.true
b.true
c.false
d.false(by diffusion,linear velosity is very low)
e.true

5.a.false
b.false
c.true
d.false(increases)

6.a.true.(severinghaus co2 electrode)
b.true(this describes Astrup technique)
c.true
d.true.
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