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

Flood disaster factors in north India

Flood devastation on increase 

Many cities in India are facing severe flood situation, 
year after year; 
causing damage to human and property, 
eroding vast areas for ecological damages with loss of valuable flora and fauna, 
most in north Himalayan states including Kashmir.  

Srinagar flood picture thankfully shared from:www.deccanchronicle.com

In recent years, studies have revealed that many factors are involved, as if working all together, to cause this havoc of enormous magnitude.

Multiple factors:
1.Fragile Himalayan region: As this part of the Himalayan region is the world's youngest an most fragile mountain range, still in the process for formation.(1)(2)

Any severity of rain event, hits it most.

2.Climate change: Indian subcontinent is witnessing climate change due to environmental degradation. 'Indian Institute of Tropical Meterology' (B. N. Goswami, Pune) studies have confirmed that heavy rainfall events are on increase with decreasing trend in moderate rainfall in Indian subcontinent. (centre for science & environment report).

3.Naturally occurring flood channel encroached: Natural flood channels were encroached due to unplanned urban development on lake banks, causing collapse of the natural drainage system.(3)

In it's natural recourse, the flood water of lower Himalayan region was to channelize into lakes (like Dal & Nageen in Kashmir region), each lake with it's own flood discharge channels which spills flood water to drainage.

Encroachment have caused in the reduction of the size of Dal lake.

panoramic view of Dal lake
picture thankfully shared from:https://en.wikipedia.org/wiki/Dal_Lake

Construction along the Jhelum bank and in it's low lying areas have caused the blockage of discharge channels of the river.

According to 'Department of Environment and Remote Sensing Data',this region carries 1230 lakes and many water bodies (150 in Jammu and 415 in Kashmir).(4)

But massive encroachment of land by constructing buildings, have destroyed this all.
What was needed in such areas are the planned urbanization.

And so this all resulted in;
a.Massive deforestation in the Jhelum basin,
b.Excessive siltation of lake and water bodies,
c.Lakes lost the power to absorb water (wetlands and lakes acts as sponges during floods), resulting in floods.

Geographical notes:

about

Jhelum river, Wular lake, Dal lake

in Kashmir, India

(information source: courtesy Google map and Wikipedia)

Jhelum river, Wular lake and Dal lake near Srinagar sate capital of Kashmir in India (Google map courtesy)

Jhelum river

The Jhelum rises from a deep spring at Vernag, in Jammu and Kashmir state, in the Indian-administered portion of the Kashmir region. The river meanders northwestward from the northern slope of the Pir Panjal Range through the Vale of Kashmir to Wular Lake, which controls its flow.

Emerging from the lake, the Jhelum breaks through the Outer Himalayas into broad alluvial plains, The total length of the Jhelum is about 450 miles (725 km).

Dal lake

One version is that it is the remnants of a post-glacial lake, which has undergone drastic changes in size over the years and the other theory is that it is of fluvial origin from an old flood spill channel or ox-bows of the Jhelum River.

Wular lake

^{One of the largest fresh water lakes in Asia, is in Bandipora district in the Indian state of Jammu and Kashmir. The lake basin was formed as a result of tectonic activity and is fed by the Jhelum River.}