The document discusses the structure and function of neurons and nerves. It notes that neurons are individual cells that make up nerve tissue and conduct nerve impulses, while nerves are bundles of neurons that transmit information to different parts of the body. There are three main types of neurons - sensory neurons that receive stimuli, motor neurons that control muscles and glands, and interneurons that transmit signals between sensory and motor neurons within the central nervous system. Nerves can be sensory, motor, or mixed depending on the neurons they contain.

1. (NERVE TISSUE)

3. BRAIN
SPINAL
CORD
CRANIAL
NERVES

4. 1.A neuron is an individual cell, whereas, a group of
neurons form a nerve(tissues)
2.There are two types of neurons (sensory and motor
neurons) while there are three types of nerves
(afferent, efferent and mixed nerves).
3.Nerves are found in the peripheral nervous system,
while neurons are found in the brain, spinal cord and
the peripheral nerves.
4.A neuron can also be called a neurone or a nerve cell.
5.Neurons conduct nerve impulses, while nerves transmit
information to various parts of the body.

5.  NERVOURS TISSUES IS A GROUP OF NERVE
CELLS(NEURONES) TOGETHER WITH
NEUROGLIA/SUPPORTING CELLS,WHICH TRANSMITS
ELECTRO-CHEMICAL MASSAGES CALLED IMPULSES
ALONG THEIR MEMBRANE
 NEURONE (NERVE CELL) IS THE BASIC FUNCTIONAL
UNITS OF THE NERVOUS SYSTEM
 NEURONES ARE CELLS SPECIALISED TO GENERATE
AND TRANSMIT NERVE IMPULSES (ACTION
POTENTIALS)
 NERVOUS TISSUE IS COMPOSED PRINCIPALLY OF
DENSELY PACKED NEURONES(SPECIALISED FOR
TRANSMITTING ELECTRICAL NERVE IMPULSES)

6.  NEURONE CONSISTS OF TWO PARTS
CELL BODY-DIFFERENT SHAPE(DEPENDS ON TYPES OF
NEURON),SURROUNDED BY PLASMA MEMBRANE,CONTAIN
A NUCLEUS LIKE ANY NORMAL CELL,HAS A LOT OF
MITOCHONDRIA, GOLGI APPARATUS,ENDOPLASMIC
RETICULUM ,RIBOSOMES(NISSL’S GRANULES),NO
CENTRIOLE
NERVE PROCESS-THIN SLENDER STRUCTURE ATTACHED TO
CELL BODY,INCLUDES AXON, DENDRON AND DENDRITES
 DENDRON TRANSMITS IMPULSES TOWARD CELL BODY
 AXON TRANSMITS IMPULSES AWAY FROM CELL BODY
 BOTH HAVE VARIOUS LENGTH(UP TO FEW METRE), PROTECT BY
MYELIN SHEATH, END WITH BRANCHED TO FORM SMALLER
DENDRITES(AXON DENDRITES END WITH LITTLE KNOBS CALLED
SYNAPTIC KNOBS)

9. NERVE CONSISTS OF MANY NEURONS BOUND
TOGETHER BY CONNECTIVE TISSUE
 SENSORY NERVE CONTAIN ONLY SENSORY NEURONES
 MOTOR NERVE CONTAIN ONLY MOTOR NEURONES
 MIXED NERVE CONTAIN BOTH SENSORY AND MOTOR
NEURONES
NEUROGLIA DO NOT GENERATE OR TRANSMIT
IMPULSES BUT FUNTION TO SUPPORT AND PROTECT
NEURONS.
TYPES OF NEUROGLIA CELL:
 ASTROCYTES,OLIGODENDROCYTES,MICROGLIAL,
EPENDYMAL CELLS, SATELLITE CELLS,SCHWANN CELLS
FORM MYELIN SHEATH OF AXONS IN THE PERIPHERAL
NERVOURS SYSTEM

10.  SENSORY (AFFERENT)
NEURONE
 INTERNEURONE
(ASSOCIATIVE /
INTERMEDIATE NEURRONE)
 MOTOR (EFFERENT)
NEURONE

12.  A sensory neuron is an electrically excitable cell that
processes information taken from one of the five
senses: sight, hearing, taste, smell, and touch.
 The peripheral nervous system of the human body,
which includes all the neurons outside brain and spinal
cord, contains a substantial fraction of these neurons.
 The initial event that causes a neuron to activate is
called a stimulus, and this can be anything from a
breeze blowing across a person's arm to a door
slamming.
 Sensory neurons on their own do not cause the human
body to react to stimuli, and a reaction only occurs
after the electrical impulses they carry have been
processed.

13.  The function and action of a sensory neuron is
always the same, no matter what type of stimulus is
being processed.
 Whether tasting a strawberry or touching something
hot, the information from that experience is passed
along the neuron as a series of impulses for
processing that the neuron cannot do itself.
 The shape and size of the cells doesn't matter
either, because the electrical signals can travel fast
enough to the point where any differences in travel
time are negligible.
 They have long dendron , short axon for
transmitting impulses from receptor to central
nervous system

15.  An interneuron (also called relay
neuron, association neuron, connector
neuron or local circuit neuron) is one of the three
classifications of neurons found in the human body.
 Interneurons create neural circuits, enabling
communication between sensory or motor
neurons and the central nervous system (CNS).
 Receives impulse from the sensory neurons and
transmits it to motor neurone
 Found in brain and spinal cord
 Some generate impulses and some transmit
impulses

16.  They have been found to function in reflexes, neuronal
oscillations, and neurogenesis in the adult mammalian brain.
 Their dendron and axon are same length for transmitting
impulses from sensory to motor neurones
 Interneurons can be further broken down into two groups:
---Local interneurons have short axons and form circuits
with nearby neurons to analyze small pieces of
information.
---Relay interneurons have long axons and connect circuits
of neurons in one region of the brain with those in other
regions.
 The interaction between interneurons allow the brain to
perform complex functions such as learning, and decision
making.
 Has various shape
 Bipolar- 1 dendrons and axons
 Multi-polar - >1 dendrons and axons

17. Bipolar
Dendron
axon
Multi-polar
axon
Dendron

19.  A motor neuron (or motoneuron) is a nerve cell
(neuron) whose cell body is located in the spinal
cord and whose fiber (axon) projects outside the
spinal cord to directly or indirectly control muscles.
 Motor neurons are efferent nerves (also called
effector neurons), that carry signals from the
central nervous system (CNS)(spinal cord) to the
effector such as gland and muscles to produce
(effect) movement
 They have short dendron and long axon for
transmitting impulse from CNS to muscles

21.  MYELIN SHEATH FORMED BY SCHWANN CELLS
AND WRAP THEMSELVES AROUND THE AXON
 THE SMALL UNCOVERED PART OF AXON
BETWEEN TWO SCHWANN CELLS ARE CALLED
NODES OF RANVIER
 MYELIN SHEATH ACTS AS AN ELECTRICAL
INSULATOR AND SPEED UP THE TRANSMISSION
OF NERVE IMPULSES
 THE ACTION POTENTIAL TRAVELS FROM ONE
NODE OF RANVIER TO ANOTHER NODE BY
SALTATORY CONDUCTION