The main function of nervous system is unification and regulation of different physiological processes.
That means that nervous system unites, integrates and subordinates all the parts of human body and provides its connection with environment

The base of nervous system activity is reflex principle
Reflex – is a reaction of our organism to various outside and inside effects. It is provided by nervous system

afferent part (which accepts information) central part (that keeps information) efferent part (that creates response)
As a result we have a circle – like structure
- receptor (primary information centre) – programme centre – executive apparatus

simple and complex inborn and trained conditioned and unconditioned

They are inborn ones
They are phylogenetically old, that means they were formed in course of phylogenesis
They are based on certain anatomic structures
(segments of spinal cord or brain stem)
They exist even without brain cortex influence
They are inherited
They can be regulated by brain cortex
They are basis for the conditioned reflexes

They are the result of the individual experience and are formed during ontogenesis
They are unstable, that means they need constant support
They aren’t based on certain anatomic structures
They are fixed in brain cortex
There are such conditioned reflexes as speaking, writing, reading, calculation, practice

Unconditioned reflexes are divided into:
Superficial and deep
Simple and complex

Unconditioned reflexes are divided into:
Proprioceptive (stretch, periosteal, joint)
Exteroceptive (dermal, from mucose membrane)
Interoceptive (from mucosa membrane of internal organs – for example urination in case of internal sphincter irritation)

Provides conduction of nervous impulse from brain cortex to muscles.
The way of this impulse is known as motorway or tractus corticomuscularis
It consists of two neurons:
Central – upper motor neuron (UMN)
Peripheral – lower motor neuron (LMN)

Upper and lower extremities, neck, trunk and perineum muscles ’ innervation
The first (central) neuron
( upper motor neuron ) is called Corticospinal tract tractus corticospinalis
The second (peripheral) neuron
( lower motor neuron ) is called Spinomuscular tract tractus spinomuscularis

Motor Homunculus

Upper Motor Neuron Corticospinal Tract

Lower Motor Neuron cell body: anterior horn axon: anterior root, spinal nerve axon terminal: neuromuscular junction
Effector: skeletal muscle

ramus anterior ( together they form plexus
– cervical, brachial, lumbar and sacral) ramus posterior (it is spinal nerve, which innervates posterior trunk muscles) ramus meningeus ramus comunicante albi

The muscles of upper and lower extremities have unilateral cortical innervation from contralateral hemisphere
The muscles of neck, trunk and pelvic organs have bilateral innervation from both hemispheres. In case of unilateral pathologic focus these structures do not suffer

Extremities, neck, trunk and perineum muscles ’ innervation
Neurons of С1-С4 anterior roots – innervate neck muscles
С5-Th1 – muscles of upper extremities
Th2-Th12 – muscles of trunk
L1-S2 – muscles of legs
S3 – S5 – muscles of perineum

Face, tongue and pharynx muscles innervation
This way is called tractus corticomuscularis
The first central neuron
( upper motor neuron ) is called tractus corticonuclearis
( Corticobulbar Tract )
The second peripheral neuron
( lower motor neuron ) is called tractus nucleomuscularis

Face, tongue and pharynx muscles innervation

We can make the following conclusions:
The face muscles have bilateral cortex innervation except the mimic muscles and tongue muscles that have unilateral innervation from the opposite hemisphere
The muscles of upper and lower extremities, lower mimic muscles and tongue muscles have unilateral cortical innervation
All the other muscles (the muscles of neck, trunk, perineum, m. oculomotorial, m. masseter, pharyngeal and palatal muscles) have bilateral cortical innervation

UMN and LMN Syndrome - Paralysis

Paralysis (plegia) - means the absence of active movements. It occurs in case of complete lesion of motor way (tractus corticomuscularis)
Paresis occurs in case of incomplete lesion of motor way. That means disorders of active movements
Clinically can be – hemi-, tetra-, mono-, triand paraparesis

Central (spastic)
Peripheral (flaccid)
Central or spastic paralysis is caused by the lesion of central neuron and its fibers (tr. corticospinalis or tr. corticonuclearis)
Peripheral or flaccid paralysis is caused by the lesion of peripheral neuron (tractus spinomuscularis or tractus nucleomuscularis)

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Features of central (spastic) paralysis are:
Hyperreflexion of Deep Tendon reflexes
Spasticity of skeletal muscles
Pathologic reflexes . They are considered to be reliable signs of central paralysis
It is a diffuse paralysis
Protective reflexes (the reflexes of spinal automatism)
Pathologic synkinesis is involuntary movements in paralysed extremity

Spastic hypertonus (Vernike-Mann posture)

Tonus is increased in the group of flexors in upper extremities and in the group of extensors in lower extremities
“Clasp – knife“ Phenomenon in course of evaluation tonus decreases

Planter response
Normal Pathologic

Features of peripheral paralysis
1. Areflexion or hyporeflexion
2. Atonia or hypotonia
3. Muscular atrophy
4. Fasciculation of muscles
5. It is limited paralysis
6. There is reaction of degeneration

Global wasting of the left arm in a posttraumatic brachial plexopathy

Muscular Atrophy

Note any of the following common gait disorders:
Hemiplegic gait with one-sided weakness
- a possible sign of cerebral stroke
Spastic gait - a possible sign of cerebral palsy
Ataxic gait - a possible indication of cerebellar dysfunction
Festinating gait - a possible sign of
Parkinson's disease