A class room lesson on brain anatomy

CONTROL & COORDINATION
1. Endocrine System; of Endocrine glands, Hormones secreted by goes directly into blood stream.
2. Nervous System; of Nerve cell/Neuron, through nerve impulses.


CONTROL & COORDINATION BY NERVOUS SYSTEM

Mainly functions as:

1. Control & coordination of/among
    a. Tissues
    b. Organ
    c. Systems (Organ Systems)
2. Perception of environment through sensory stimulus received by 'Sensory Organs'


DIVISIONS OF NERVOUS SYSTEM
A. CENTRAL NERVOUS SYSTEM
     a. Brain
     b. Spinal Cord
B. PERIPHERAL NERVOUS SYSTEM
     a. Cranial Nerves
         i. 12 pairs
         ii. Sensory, Motor, Mix types
     b. Spinal Nerves
         i. 31 pairs
         ii. Sensory from the Dorsal Root
         iii. Motor from the Ventral Root
C. AUTONOMIC NERVOUS SYSTEM
     Never are they connected to any body organ diectly
     Are of 2 Neurons type: 
          Preganglionic Nerves and Post Ganglionic Nerves
     Autonomous Nervous System is of two types:
         a. Sympathetic or Thoracolumber system
             Chest and lumber region
         b. Parasympathetic or Craniosacral system
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CENTRAL NERVOUS SYSTEM
comprising 2 main structures

1. Brain
    (enclosed in bony skeleton of Cranium)

2. Spinal Cord
    (enclosed in bony skeleton of Vertibral Column)

Meninges, the three layered connective tissue membrane covers Brain and Spinal Cord both from outside. These membranes of Meninges are Duramater, Arachnoid and Piamater from outside to inside.
Piamater joining brain surfaces in the brain cavity, at two places it forms finger like inward projection inside brain, called Choroid Plexus.

Cerebrospinal Fluid (CSF),
is a kind of lymph
acts as to and fro communicating medium between blood and brain cells
protects brain and spinal cord from external shocks.

Brain covered from outside to inside as, Cranium (bone), with 3 layers of meninges (Duramater, Arachnoid, Piamater) with their spaces Epineural, Subneural, Subarachnoid spaces.  Subneural space is full of reticulum of bood capillaries and blood sinuses.

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Brain
1400 grams in weight, approximately
Enclosed in the Cranium of bone
Bilaterally symmetrical
Made of Neuron, which is
  i. Grey Matter, outside portion of brain, comprising Cyton of Neuron
  ii. White Matter, inside portion of brain, comprising Nerve Fibre of Neuron

It is divisible into 3 main parts:
a. Fore Brain (Prosencephalon)
    i. Cerebrum
    ii. Diencephalon
b. Mid Brain (Mesencephalon)
    i. Cerebral peduncle
    ii. Corpora quadrigemina
c. Hind Brain (Rhombencephalon)
    i. Cerebellum
    ii. Pons
    iii. Medulla oblongata

a. Fore Brain (Prosencephalon)
    i. Cerebrum
       Left and Right, two Cerebral Hemisphere
       Both separated from each one by a long groove in centre
       Both hemisphere are attached to each other by a  Neuron plate called Corpus Callosum
       This form 2/3 or 7/8 part of all brain

Right and Left Cerebral Hemisphere, showing Corpus Callosum

Each Cerebral Hemisphere is divisible in 4 lobes by three deep grooves, as
i. Frontal lobe
ii. Parietal lobe
iii. Temporal lobe
iv. Occipital lobe

Left and Right Cerebral Hemisphere of Cerebrum separated by Median Dorsal Line in Ventral and Dorsal view

Cerebral Cortex
Outer region of Cerebral hemisphere, made of Grey Matter, numerous Neurons

Gyri and Sulci
The folds formed in this part are called Gyri and Sulci
Protrding part of tghe fold is Gyri and sunken part is called Sulci
This is 1.5-4 mm in thickness
This enables the packing of nemerous  Neurons in a small place
If this part extended, cover 4000 sq. cm., comprising 10-14 billion Neurons

Cerebral Nuclei
Islands of Grey Matter are found in the White Matter are called Cerebral Nuclei

Function of Cerebrum
Frontal lobe is General Motor area while other lobes are General Sensory Area in function.

Premotor Area of Frontal Lobe controls movement of Unstriped muscles while Motor area controls the movement of Striped muscles.
Somaesthetic area of Parietal lobe is a centre of cold, hot, touch, light reflexes.
Temporal lobe governs smell and taste.
Occipital lobe is for sight and hearing.

Cerebrum stands for all for which humans are recognized as special from rest of the life forms, that is
Conscience, Intellect, Thinking, Memory, Desires, Control on various emotion, Control on laugh and weep, Understandind,Understandind and decision making in respect of sensory and other perceptions.

There are separate cenre for each sensory impulses received in Cerebrum.

ii. Diencephalon
This is the hind part of the Fore Brain
It is small, rectangular in shape
It is fully covered by Cerebral hemisphere from dorsal side front portion, while it is covered by Mid brain from behind
The ventricle is called as Third Ventricle or Diocoel
This is made up by two structures:
   # Thalamus: two round projections of Grey Matter in Diocoel
   # Hypothalamus: at the bottom surface of Diocoel, islands of Grey Matter in White Matter

Functions
1. Thalamus
    Sending Sensory and Motor stimulus from Medulla oblongata and Spinal cord to Cerebrum
    Controls emotions, heat, cold, pain
2. Hypothalamus
    Coordination between Nervous system and Endocrine system
    Controls Autonomous Nervous system 
    Control on Carbohydrate and Fat metabolism

b. Mid Brain (Mesencephalon)
    i. Cerebral Peduncle
       A thick path of Nerve fibres which connects Cerebrum and Cerebellum
       It's ventricle is called Iter which connects third ventricle of Diencephalon to fourth ventrile of              Medulla 
           Functions:
             a. Reflex centre
             b. Sending Motor stimulus of Cerebrum to limbs
    ii. Corpora Quadrigemina
        Four, solid, round protuberance found on the dorsal surface of mid brain 
           Functions:
             a. Sight and smell reflex centre

c. Hind Brain (Rhombencephalon) 
    i. Cerebellum
       This is second largest part of the brain
       Divisible into three parts
       Cerebellar cortex is made of Grey Matter
       Central Fibre tract is made of White Matter
         a. Vermis, central part
         b. Lateral lobes, two in number
             Functions:
                Contraction and relaxation of Skeletal muscle
                Control on voluntary movement initiated by Cerebrum
                Body balance, to be in upright position
                Coordination in movements of body
    ii. Pons Varoli
        Pons are found in upper and front part 
        This is in form of thick poo; of nerve fibres
        Joints left and right lobes of Cerebellum
        Controls muscle movements of both sides of the body

    iii. Medulla
         This is hind most part of the brain, also called Brain Stem
         Lateral walls are thick, made of White Matter
         Islands of Grey Matter on ventral surface with neurons
             Functions:
               a. Vital Centre
                   Respiratory centre
                   Cardiac centre
                   Gastric centre
               b. Reflex centre
                   Swallowing centre
                   Vomitting centre
                   Choking centre
                   Salivary centre
               Sending Spinal nerve stimulus, from Spinal cord to Brain
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Ventricles of the brain are as labelled in diagram below

Science Through Fiction Pages: Acceptable Risk

"A classic is a book that has never finished saying what it has to say."  

Italo Calvino

A bookworm

It happens so often that we prove our self a perfect bookworm when we communicate so much with the subject that the book becomes a reporting page with all the allied branches of human knowledge converging to, in a particular time and space of ours.

Acceptable Risk  

A 1994 Robin Cook's best selling medical thriller, which narrates the story of a young researcher isolating a stunningly effective anti-depressant from a mould first uncovered over 200 years ago. But there is more to the drug than anyone could have imagined....

 And when we love some subject, then the book becomes classic of it's own kind as it starts saying through our inscriptions on the same very pages of it !!

Some other source of alkaloid in nature

A curiosity took me to see Chem. Abstr. 1961,16915p and 1964, 60, 3945 p to know that this D-Lysergamide whose molecular formula is C₂₀H₂₅N₃O

^{And these chemical actually mimic the brain actions causing hallucination and delusions, which also found in :}

^{# Ipomea tricolor (Syn. I. violaceae) morning glory, family Convolvulaceae. Ergot alkaloid in seeds, producing psychosis like state.}

^{# Ergot disease of rye due to fungus Claviceps purpurea, may cause....}

^{# Ergotism in humans} 

The mystery molecule

The book amazes most as we find that: 
the molecular structure of the central character of this novel on a super computer by a new structural software, which reveals that:

Four ringed structural core of the compound, with five side chains, one was tetra cyclic and resembled LSD, another had two rings and resembled drug called Scopolamine. The last three resembled the brain's major neurotransmitters: norepinephrine, dopamine and serotonin.

Structural details of Central Nervous System of humans, mid brain highlighted

 ^{Our central Nervous system
And of course when it comes to Central Nervous System, brain and out of it's three major parts: Prosencephalon, Mesencephalon and Rhombencephalon;  
Mid brain i.e. Mesencephalon is focused in the story as this part deals with Reflex and Instinct.}

A Neuron body and mid brain in detail which controls the instinct and reflexes

^{Our mid brain is a mystery place}

<sup>Perhaps the young researchers have had the 'Shakes' belief that 'body can achieve, what mind can conceive'. 

Between the synapses of Neuron lies the chemical code transaction and this was the place where LSD mimics the brain. 

Extremely amazing cells are Neuron as they conduct electrical impulses up to synapses. 100 A° thickness of the neuron cell bears 70 to 90 millivolt of resting potential which is equal to 100,000 volt per centimeter. Amazing bio insulator is the plasma membrane.</sup>

<sup>Well, mid brain is going to play a major role here as this is also the part of brain of our ancestors of Jurassic period, need less to say that we humans are the carriers of Reptilians brain structure. 

So reptilian traits are going to be enhanced in this story due to this intake of chemical being tested on them self....as this is the part which deals with Instinct and Reflexes.</sup>

				Some relevant references of those times Science In The News: Voice Of America: 5th March 1996, Tuesday  Tobacco and Asbestos are known to cause Cancer. Earlier studies found that Beta Carotine (which breaks in to Vitamin A in our digestive system) have preventive effect in such cases only when taken in natural form, not in the form of pills. So isolation from the fungus extract, the pure form of LSD-25 was sure as going to cause a havoc in the story..........this way or that !! Some relevant references of those times  Science In The News: Voice Of America: 5th March 1996: Tuesday Food and Drug Administration (USA) approved a synthetic 'fat substitute' developed by Proctor and Gamble scientist after 20 years of research studies, altering the molecular structure of Sugar, adding fat in it's side chain, recommending to use as snacks (with potato chips), named Olestra (derived from Olein), 30 grams of which may give 10 grams of fat (vitamin A,D,E,K to be added along with), passing through human system as Carbose without recognizing and storing (by body) it as fat. But alarming is this human endeavor as: certain studies say it may cause stomach pain and mild diarrhea and further warned ----it may cause heart disease and cancer. All kind of possible alarming hazards were put aside by the team of these young researchers in this book. Kim (she) and Edward (he); Central human characters from the book: They identified their identical identities, but the mould which molded their destinies on unidentical tracks. The end of the story:  Fallacy/Irony/Tragedy........hard to choose from !!

And if I were Kim and Edward, both characters of this book 'Acceptable Risk', I had to put my feelings in a poem as below to express myself:

Someday
I would crumble down

Due my own sins,

And it's sheer pressure

Will cause me to

Turn in to the matter

----Like white dwarfs

----In to the dark matter

----To become a part of the universe
----Which is 90 percent

----Yet unseen !!

(Anjani)

Molecular structure of alkaloid D-Lysegamide

Notes related:

Dr. Robin Cook: is an American physician and novelist who writes about medicine and topics affecting public health. To date, he has explored issues such as organ donation, genetic engineering, fertility treatment, in - vitro fertilization, research funding, managed care, medical malpractice, medical tourism, drug research, and organ transplantation.^[8] 
Some notes about or by author: # I joke that if my books stop selling, I can always fall back on brain surgery," he says. "But I am still very interested in it. If I had to do it over again, I would still study medicine. I think of myself more as a doctor who writes, rather than a writer who happens to be a doctor." He explained the popularity of his works thus: "The main reason is, we all realize we are at risk. We're all going to be patients sometime," he says. "You can write about great white sharks or haunted houses, and you can say I'm not going into the ocean or I'm not going in haunted houses, but you can't say you're not going to go into a hospital.^[7]
# Cook says he chose to write thrillers because the forum gives him "an opportunity to get the public interested in things about medicine that they didn't seem to know about. I believe my books are actually teaching people."^[8]
# The author admits he never thought that he would have such compelling material to work with when he began writing fiction in 1970. "If I tried to be the writer I am today a number of years ago, I wouldn't have very much to write about. But today, with the pace of change in biomedical research, there are any number of different issues, and new ones to come," he says.^[7]