Introduction of basic neurosciences

1. ITTRODUCTION
OF BASIC
NEUROSCIENCE
By-SHAILENDRA SHARMA

2. BASIC NEUROSCIENCE
 OVERVIEW OF NERVOUS SYSTEM
 Your nervous system is your body's command center. Originating
from your brain, it controls your movements, thoughts and automatic
responses to the world around you. It also controls other body systems
and processes, such as digestion, breathing and sexual development
(puberty)

3. The Nervous System has three specific functions:
1.Sensory Input - Sensory receptors present in the skin and organs respond
to external & internal stimuli by generating nerve impulses that to the central
nervous system
2.Integration - The brain and spinal cord of the Central Nervous System
combine and sum up all the data received from the body and send out nerve
impulses.
3.Motor Output - The nerve impulses from the Central Nervous System go
to the effectors (muscles and glands). Muscle contractions and
gland secretions are responses to stimuli received by sensory receptors.
The Nervous System is divided into two main divisions.

5. CENTRAL NERVOUS SYSTEM-
The CNS two parts: Brain; Spinal Cord
1.Brain
The Brain is divided into four main parts[1]:
•Brain stem, consisting of the medulla, pons, and midbrain
•Cerebellum
•Diencephalon, with the thalamus and hypothalamus
•Cerebral hemispheres (comprised of the cerebral cortex, basal ganglia, white
matter, hippocampi and amygdalae). The right and left hemisphere are connected
by the corpus callosum which facilitates communication between both sides of the
brain. The Hemispheres are then further divided into four lobes

6. 2. The Spinal Cord (the caudal extension of the CNS).
Neurological Conditions: many neurological conditions affect the CNS.
They range dramatically in scope, impact, and nature of the effect.
Some conditions lead to progressively impaired movement
eg Parkinson disease. Huntington chorea. The demyelination
in multiple sclerosis can cause acute attacks, and over time, chronic
degradation of function.

7. Neurone are cells of the nervous system, located within the grey matter, and
responsible for all neurological functions of the brain.
They are any of the impulse-conducting cells that constitute the brain, spinal
column, and nerves in vertebrates, consisting of a nucleated cell body with one or
more dendrites and a single axon. See Neurone link for more detailed informatio

8.  Cerebrum-
The cerebrum consists of two cerebral hemispheres, the right and left hemisphere
are connected by the corpus callosum which facilitates communication between
both sides of the brain, with each hemisphere in the main connection to the
contralateral side of the body i.e. the left hemisphere of the cerebrum receives
information from the right side of the body resulting in motor control of the right side
of the body and vice versa.

10. Neurological cell-
The brain is made up of more than just neurones. Although there are about 86-100
billion neurons in the brain, there are about the same number of glial cells in the
brain. Glial cells, or neuroglia, are cells that surround the neurones of the central
nervous system embedded between them, providing both structural and
physiological support

12. SPINAL CORD-
The spinal cord is part of the central nervous system and consists of a tightly
packed column of nerve tissue that extends downwards from the brainstem
through the central column of the spine. It is a relatively small bundle of tissue
(weighing 35g and just about 1cm in diameter) but is crucial in facilitating our
daily activities.
 The spinal cord carries nerve signals from the brain to other parts of the
body (importantly the muscles we use to move) and receives sensory input
from the body, partially processes it, and then transmits that information to
the brain.

13.  Peripheral Nervous System Definition
‘’Peripheral nervous system involves the parts of the nervous system outside
the brain and the spinal cord.”
Peripheral Nervous System
The peripheral nervous system has two divisions:
•Somatic Nervous System
•Autonomic Nervous System
Somatic Nervous System
The main function of the somatic nervous system is to transfer impulses from CNS to
skeletal muscles.
It consists of
•Cranial Nerves
•Spinal Nerves

14.  Autonomic Nervous System-
The autonomic nervous system relays impulses from the central nervous system to the involuntary
organs and smooth muscles of the body.
It is divided into two parts –
•Sympathetic Nervous System
•Parasympathetic Nervous System
The sympathetic nervous system consists of nerves arising from the spinal cord between the neck
and waist region. It prepares the body for violent actions against abnormal conditions and is generally
stimulated by adrenaline.
The parasympathetic nervous system is located anterior in the head and neck and posterior in the
sacral region. It is mainly involved in the re-establishment of normal conditions when violent action is
over.

15.  Peripheral Nervous System Functions
Following are the important functions of the peripheral nervous system:
1.The peripheral nervous system connects the brain and the spinal cord to the rest of
the body and the external environment.
2.It regulates internal homeostasis.
3.It can regulate the strength of muscle contractility.
4.It controls the release of secretions from most exocrine glands.

16. QUESTION-1 What is the difference between the central nervous system and the
peripheral nervous system?
ANSWER-The central nervous system (CNS) consists of the brain and spinal cord. It
helps in information processing. The peripheral nervous system (PNS) consists of
cranial and spinal nerves. PNS is involved in the movement, stimulus-response and
physiological changes.
QUESTION-2 What are the three types of nerves which constitute the peripheral nervous system?
ANSWER-The three types of nerves which constitute the peripheral nervous system are:
a) Spinal nerves.
b) Cranial nerves.
c) Visceral nerves.

17. CENTRAL NERVOUS SYSTEM
 Definition-
‘’The central nervous system (CNS) consists of the brain and spinal cord. This
body system is responsible for integrating and coordinating the activities of the
entire body. Through these physical structures, thought, emotion, and sensation
are experienced, and body movements are coordinated’’.

18. FUNCTION OF CENTRAL NERVOUS SYSTEM-
Coordination and Movement
The primary function of the central nervous system is integration and
coordination. The CNS receives input from a variety of different
sources, and implements an appropriate response to the stimuli, in a
cohesive manner.
Thought and Processing
The CNS, especially the brain, is considered the physical seat for most
higher-order mental functions. Neuronal connections form the basis for
thought and retention of memory.

19. Cytology of Neuron
• Neurons have common features that distinguish them from cells in other tissues.
– They typically are highly polarized.
– Cell functions are compartmentalized, an arrangement that contributes significantly to the
processing of electrical signals.
– The chief functional compartments of neurons are
• cell body, dendrites, axons, and terminals and these are usually separated by considerable
distances

20. Axon: Also known as a nerve fiber. Axons is long, slender projection of a nerve cell, and
conducts electrical impulses away from the neuron's cell body.
Dendrites : Branched projections of a neuron those which conduct the electrochemical
stimulation received from other neural cells to the cell body, or soma, of the neuron
 The cytoskeleton is the major intrinsic determinant of the shape of a neuron and
is responsible for the asymmetric distribution of organelles within the cytoplasm.
It contains three main filamentous structures:
– Microtubules
– Neurofilaments (called intermediate filaments in nonneuronal cells)
– Microfilaments (actin microfilaments)

21.  COMPONENTS OF NEURONS-
A neuron has three main parts: dendrites, an axon, and a cell body or
soma (see image below), which can be represented as the branches, roots
and trunk of a tree, respectively. A dendrite (tree branch) is where a neuron
receives input from other cells.

22. QUESTION-1 WHAT ARE THE NISSL GRANULES ?
ANSWER=Nissl bodies (also called Nissl granules, Nissl substance or tigroid
substance) are discrete granular structures in neurons that consist of rough
endoplasmic reticulum, a collection of parallel, membrane-bound cisternae studded
with ribosomes on the cystosolic surface of the membranes.
QUESTION-2 WHAT IS THE GOLGI STAINING ?
ANSWER= Golgi's method is a silver staining technique that is used to
visualize nervous tissue under light microscopy. It was initially named the black
reaction (la reazione nera) by Golgi, but it became better known as the Golgi stain or
later, Golgi method.

23. QUESTION-3 WHAT IS THE FUNCTION OF AXON ?
ANSWER=Each neuron in your brain has one long cable that snakes away from
the main part of the cell. This cable, several times thinner than a human hair, is
called an axon, and it is where electrical impulses from the neuron travel
away to be received by other neurons.
NOTE-The function of the axon is to transmit information to different
neurons, muscles, and glands.

24. QUESTION-4 WHAT IS THE DIFFERENCE BETWEEN AXON AND DENDRITE ?

25. QUESTION-5 WHAT IS THE CEREBROSPINEL FLUID ?
ANSWER= Cerebrospinal fluid is a clear, colorless body fluid found within the
tissue that surrounds the brain and spinal cord of all vertebrates. CSF is
produced by specialised ependymal cells in the choroid plexus of the ventricles
of the brain, and absorbed in the arachnoid granulations.
QUESTION-6 WHAT IS THE FUNCTION OF CEREBROSPINEL FLUID?
ANSWER-Cerebrospinal fluid acts like a cushion that helps protect your brain
and spinal cord from sudden impact or injury. The fluid also removes waste
products from the brain and helps your central nervous system work properly

26. QUESTION-7 WHAT IS THE SPINEL CORD AND IT’S FUNCTION ?
ANSWER-A column of nerve tissue that runs from the base of the
skull down the center of the back. It is covered by three thin layers of
protective tissue called membranes. The spinal cord and membranes are
surrounded by the vertebrae (back bones). The spinal cord and the brain
make up the central nervous system (CNS).

27. FUNCTION OF SPINEL CORD-
•Carrying signals from the brain: The spinal cord receives signals from the brain
that control movement and autonomic functions.
•Carrying information to the brain: The spinal cord nerves also transmit
messages to the brain from the body, such as sensations of touch, pressure, and
pain.
•Reflex responses: The spinal cord may also act independently of the brain in
conducting motor reflexes. One example is the patellar reflex, which causes a
person’s knee to involuntarily jerk when tapped in a certain spot.

28. QUESTION -8 WHAT IS THE SYMPHATIC NERVOUS SYSTEM AND IT’S
FUNCTION ?
ANSWER -Your sympathetic nervous system is a network of nerves that helps your
body activate its “fight-or-flight” response. This system’s activity increases when you’re
stressed, in danger or physically active. Its effects include increasing your heart rate
and breathing ability, improving your eyesight and slowing down processes like
digestion.
 FUNCTION-The main functions of the sympathetic nervous system are
to dilate blood vessels, increase blood pressure, contract muscles,
secrete sweat from sweat glands, dilate bronchi for more oxygen
exchange and contraction of heart which helps the body prepare to face
emergency situations.

29. QUESTION -9 WHAT IS THE PARASYMPATHETIC NERVOUS SYSTEM ?
ANSWER - parasympathetic nervous system is a network of nerves that
relaxes your body after periods of stress or danger. It also helps run life-
sustaining processes, like digestion, during times when you feel safe and
relaxed.

30. QUESTION-9 What’s the difference between the sympathetic and
parasympathetic nervous systems?
ANSWER- Your sympathetic and parasympathetic nervous systems
roles. While your sympathetic nervous system carries signals that
systems on alert, your parasympathetic carries signals that relax
The two systems work together to keep your body in balance. Your
nervous system takes the lead for as long as is necessary to get you
period of danger. Then, your parasympathetic nervous system steps
returns things to normal.

31. QUESTION -10 WHAT IS THE MYELINATION?
ANSWER = Myelination is the process by which
brain oligodendrocytes produce layers of myelin that wrap around the
neuronal axons and act as a layer of insulation for the transmission of
electric action potentials down the neuronal axon.

32. QUESTION -11 WHAT IS THE SYNAPS NERUV CONDUCTION ?
ANSWER = In the nervous system, a synapse is a structure that permits a neuron
(or nerve cell) to pass an electrical or chemical signal to another neuron or to
the target effector cell.

33. QUESTION –12 WHAT IS THE SYNAPTIC PLASTICITY ?
ANSWER- Plasticity is the ability of the brain to change and adapt to new information. Synaptic
plasticity is change that occurs at synapses, the junctions between neurons that allow them to
communicate.
QUESTION-13 What is the function of synaptic plasticity?
ANSWER= Synaptic plasticity controls how effectively two neurons
communicate with each other. The strength of communication between
two synapses can be likened to the volume of a conversation.

34. THANK YOU
BY-SHAILENDRA SHARMA