3. Evolution of Vertebrate
Nervous System:
Evolution of vertebrates can be explained on the
basis of three characters named as:
Bilateral symmetry
Notochord
Tubular nerve cord
4. Bilateral symmetry:
Body plan that divides the animals
body into right and left sides that
are mirror images of each other.
5. Notochord
It is a cartilaginous skeletal
rod lying ventral to neural tube,
present in all vertebrates
during embryological phase
but can be reduced or absent
in adults. It basically turns to
vertebral column in most of the
vertebrate species.
7. The anterior end enlarges to
form brain vesicles, and the
rest becomes the spinal
cord.
8. Unlike the spinal cord, which has changed
little in structure during vertebrate
evolution, the brain has changed
dramatically. The ancestral vertebrate brain
of fishes and early tetrapods expanded to
form a deeply fissured and enormously
intricate brain in the lineage leading to
mammals. It reaches its greatest
complexity in the human brain.
9. In vertebrates the sensory
fibres and motor fibres
leave the cord in dorsal and
ventral roots. These roots
unite in as nerves.
13. Overall Structure:
The nervous system can be
divided into two major regions
the central and peripheral nervous
systems.
The central nervous system (CNS)
is the brain and spinal cord
The peripheral nervous system
(PNS) is everything else
14. Overall Structure:
The brain is contained within
the cranial cavity of the skull
The spinal cord is contained
within the vertebral cavity of
the vertebral column.
15. Overall Structure:
These two regions within nervous
system structures are often referred to
as
gray matter (the regions with many cell
bodies and dendrites)
white matter (the regions with many
axons).
16. Overall Structure:
Nervous tissue, present in both the
CNS and PNS
contains two basic types of cells:
neurons and glial cells.
A glial cell is one of a variety of cells
that provide a framework of tissue
that supports the neurons and their
activities.
The neuron is the more functionally
important of the two, in terms of the
communicative function of the
nervous system.
17. Basic Fuction:
The nervous system is involved in
Receiving information about the environment around us
(sensation) and
Generating responses to that information (motor
responses).
The nervous system can be divided into regions that are
responsible for sensation (sensory functions) and for the
response (motor functions).
18. Basic Fuction:
Sensation
The first major function of the nervous system is
sensation—receiving information about the environment
to gain input about what is happening outside the body
(or, sometimes, within the body).
The sensory functions of the nervous system register the
presence of a change from homeostasis or a particular
event in the environment, known as a stimulus.
19. Basic Fuction:
Response
The nervous system produces a response on the basis of
the stimuli perceived by sensory structures.
An obvious response would be the movement of muscles,
such as withdrawing a hand from a hot stove, but there
are broader uses of the term.
The nervous system can cause the contraction of all three
types of muscle tissue.
20. Basic Fuction:
Response
The nervous system produces a response on the basis of
the stimuli perceived by sensory structures.
An obvious response would be the movement of muscles,
such as withdrawing a hand from a hot stove, but there
are broader uses of the term.
The nervous system can cause the contraction of all three
types of muscle tissue.
21. Basic Fuction:
Responses can be divided into those that are voluntary or
conscious (contraction of skeletal muscle) and those that
are involuntary (contraction of smooth muscles, regulation
of cardiac muscle, activation of glands).
Voluntary responses are governed by the somatic nervous
system and involuntary responses are governed by the
autonomic nervous system,
22. Basic Fuction:
Integration
Stimuli that are received by sensory structures are
communicated to the nervous system where that
information is processed. This is called integration.
Stimuli are compared with, or integrated with, other
stimuli, memories of previous stimuli, or the state of a
person at a particular time. This leads to the specific
response that will be generated.
25. Peripheral nervous
stystem
It is an other type of nervous system.
The peripheral nervous system is the connection
line between the central nervous system and the
overall body parts.
It includes nerve cell which are arise from the
26. Peripheral Nervous Sytem In
Vertebrate
It collect information and send commands containg nerve that
extend to and from the spinal cord.
On the basis of function and structure ,it is divided in to:
i- Afferent nerve
ii- Efferent nerve
iii- Somatic nerve
Iv-Autonomic nerve
27. Afferent Nerves
It collect sensory information from
the body and transfer to the CNS. It
is also called sensory nerves.
28. Efferent Nerves
It bring commands the CNS to the
body. It is also called motar nerve.
29. Somatic Nerves(conscious
control)
Somatic nerve send motor
commands from the CNS to
voluntarily controlled muscles.
It is made up of cranial and spinal
nerve that contain motor nerve.
without somatic nervous system
animal are not able to respond to its
environment.
30. Autonomic
Nerves(Unconscious control)
It is an involuntarily in function. It is
also made up of cranial and spinal
nerve that contain motor neuron.
Under Unconscious control such as:
Heart beat, blinking of eyes, etc.
Autonomic nervous system is further
divided in to two types.
i) sympathetic nervous system.
Ii) parasympathetic nervous system.
31. Sympathetic Nervous
System.
It control the “fight or flight” reaction
associated with the short term
stress responses.
Eg: an accelerated heart rate and
inhibited digestion
32. Parasympathetic Nervous
System.
It control the “rest and digest”
activities involved in conserving and
restoring energy. The
parasympathetic actually resets
organ nervous system.
Effect of the parasympathetic
nervous system on target organ.
Such as: slowing of heart rate and
stimulation of digestion.
33. Diseases Of The Peripheral
Nervous System
There are a number of diseases and disorders that can effect
the peripheral nervous system.
Some of the conditions that can effect the PNS include:
i) Diabetes
ii) Peripheral nerve injuries
iii) Tumors
iv) Vitamin deficiency
34. Symptoms :
Symptoms of PNS diseases and disorders
can include numbness pain, burning,
sensitivity to touch, and muscles weakness
35. Reflex:
Reflex action, is an involuntary and nearly instantaneous
movement in response to any internal or external stimuli .
Reflex Arc:
A reflex is made possible by neural pathways its called reflex
arcs which can act on an impulse before that impulse reaches
the brain.
36. Parts Of Reflex Arc:
There are five different parts of reflex arc:
i) Sensor
ii) Sensory neuron
iii) Control center
iv) Motor neuron
v) muscles
37. Sensor:
Reflex start in structure called sensor. These structures detect
different kinds of energy. Such as touch, heat, light, smell etc.
Sensory Neuron:
Each reflex has a sensory neuron. These neuron begins a
nerve impulse that travels to the spinal cord or to the brain.
Such as eyes, ears, muscles and other body parts.
38. Control Center
In the spinal cord the sensory neuron splits into at least three
branches. Each branch forms a synapse with one of three
different kinds of cells.
One branch connects to a cell called an interneuron. These
interneuron send a message up the spinal cord to let the
cerebral cortex.
Another branch goes to the motor neuron for the bicep and
tricep muscles of the arm.
The third branch goes to another interneuron that makes a
connection to the motor neuron.
39. Motor Neuron
This part of reflex are is called the output phase. The these
things happen at once during the output phase.
The nerve impulse to the motor neuron travels out to the
biceps. The nerve impulse out is carried along an interneuron a
short distance to the motor neuron for the biceps.
A message travelling along interneuron starts its long trip to the
cerebral cortex
40. Muscles:
It is the part of reflex arc. A message from a motor neuron tell
your muscles to contract and relex the biceps and triceps
muscles.
