nerbyos sistem

8/7/2019 nerbyos sistem

1/40

Nervous System (part 2)reported by: tahseen raza p ahmad


2/40

Protection of the Central Nervous System

Scalp and skin(epithelium)

Skull and vertebral column(bone)

Meninges(membranes)

Cerebrospinal fluid(watery cushion)

Blood brain barrier


3/40

Meninges

Dura mater (tough or hard mother)

Double-layered external covering

Periosteum attached to surface of the skull

Meningeal layer outer covering of the brain andspinal cord

Folds inward in several areas

falx cerebri

Outermost layer


4/40

Meninges

Arachnoid layer

Middle layer

Web-like

Pia mater (gentle mother)

Internal layer

Clings to the surface of the brain and spinal cord

following every fold


5/40

Cerebrospinal Fluid (CSF)

Similar to blood plasma composition

Formed by the choroid plexus

Forms a watery cushion to protect the brain Circulated in arachnoid space, ventricles, and

central canal of the spinal cord


6/40

Ventricles and Location of the

Cerebrospinal Fluid


7/40

Ventricles and Location of the Cerebrospinal Fluid


8/40

Blood Brain Barrier

Includes the least permeable capillaries of the body

Excludes many potentially harmful substances

Useless against some substances

Fats and fat soluble molecules

Respiratory gases

Alcohol

Nicotine

Anesthesia


9/40

Spinal Cord

Extends from themedulla oblongata tothe region of T12

Below T12 is thecauda equina (horsetail) (a collection ofspinal nerves)

Enlargements occurin the cervical andlumbar regions


10/40

Spinal Cord Anatomy

Exterior white mater conduction tracts

Figure 7.19


11/40

Spinal Cord Anatomy

Internal gray matter - mostly cell bodies

Dorsal (posterior) horns

Anterior (ventral) horns


12/40

Spinal Cord Anatomy

Central canal filled with cerebrospinal fluid


13/40


14/40

Peripheral Nervous System

Nerves and ganglia (neuronal cell bodies)

outside the central nervous system

Nerve is a bundle of neuron fibers Neuron fibers are bundled by connective tissue

(endoneurium)


15/40

Structure of a Nerve

Endoneurium

surrounds each fiber

Groups of fibers are

bound into fascicles by

perineurium

Fascicles are bound

together by epineurium

Figure 7.20


16/40

Classification of Nerves

Mixed nerves

carrying both sensory and motor fibers

e.g. spinal nerves Afferent (sensory) nerves carry impulses

toward the CNS

Efferent (motor) nerves carry impulses awayfrom the CNS


17/40


18/40

Distribution of Cranial Nerves

sensory for smell

sensory for vision

motor fibers to eye

muscles

motor fiber to eye

muscles

sensory for the

face; motor fibers

to chewing

muscles

motor fibers to

eye muscles

sensory for taste;

motor fibers to the

face

sensory for

balance and

hearing

sensory for taste;

motor fibers to the

pharynx

sensory and motor

fibers for pharynx,

larynx, and viscera

motor fibers to neck

and upper back

motor fibers to tongue


19/40

Spinal Nerves

There is a pair of spinal nerves at the level of

each vertebrae for a total of 31 pairs

Spinal nerves are formed by the combinationof the ventral and dorsal roots of the spinal

cord

Spinal nerves are named for the region from

which they arise


20/40

Anatomy of Spinal Nerves

Spinal nerves divide soonafter leaving the spinal

cord

Dorsal rami serve the

skin and muscles ofthe posterior trunk

Ventral rami forms a

complex of networks

(plexus) for the

anterior


21/40

Spinal Nerves

Cervical

Body Areas Served

Result of Damage to

Plexus or its Nerves

Diaphragm and

muscles of shoulder

and neck

Respiratory paralysis

Brachial

Deltoid muscle of shoulder;

Triceps and extensor

muscles of the forearm

Paralysis and atrophy

of deltoid muscle

Wristdrop- inability to

extend hand at wrist

Lumbar

Lower abdomen, buttocks

anterior thighs, and skin of

antereomedial legand thigh;

Adductor muscles of medial

thigh and small hip muscles;

skin of medial thigh and hip joint

Inability to extend leg

and flex hip; loss of

cutaneous sensation

Inability to adduct

thigh

Sacral

Lower trunk and posterior

surface of thigh (and leg);

Lateral aspect of leg andfoot

Inability to extend hip

and flex knee;sciatica

Footdrop- inability to

dorsiflex foot


22/40

Examples of Nerve Distribution


23/40

Autonomic Nervous System

The involuntary branch of the nervous system

Consists of only motor nerves

Regulates cardiac muscles, smooth musclesand glands

Divided into two divisions

Sympathetic division

Parasympathetic division


24/40

Differences Between Somatic and

Autonomic Nervous Systems

Nerves

Somatic one motor neuron

Autonomic preganglionic and postganglionic

nerves

Effector organs

Somatic skeletal muscle

Autonomic smooth muscle, cardiac muscle,and glands


25/40

Differences Between Somatic and

Autonomic Nervous Systems

Nerurotransmitters

Somatic always use acetylcholine

Autominic use acetylcholine, epinephrine, or

norepinephrine


26/40

Comparison of Somatic and Autonomic Nervous Systems


27/40

Anatomy of the Sympathetic Division

Originates from T1 through L2

Ganglia are at the sympathetic

trunk (near the spinal cord)

Short pre-ganglionic neuron andlong postganglionic neuron

transmit impulse from CNS to the

effector

Norepinephrine and epinephrine

are neurotransmitters to the

effector organs


28/40

Sympathetic Pathways


29/40

Anatomy of the Parasympathetic

Division Originates from the brain stem and S1 through

S4

Terminal ganglia are at the effector organs

Always uses acetylcholine as a

neurotransmitter


30/40

Anatomy of the Autonomic Nervous System


31/40

Autonomic Functioning

Sympathetic fight-or-flight

Response to unusual stimulus

Takes over to increase activities

Remembered as the E division = exercise,

excitement, emergency, and embarrassment


32/40

Autonomic Functioning

Parasympathetic housekeeping activites

Conserves energy

Maintains daily necessary body functions

Remember as the D division - digestion,

defecation, and diuresis


33/40

Development Aspects of the Nervous System

The nervous system is formed during the firstmonth of embryonic development

Any maternal infection can have extremely harmful

effects

The hypothalamus is one of the last areas of the

brain to develop

No more neurons are formed after birth, but

growth and maturation continues for several years The brain reaches maximum weight as a young

adult


34/40

Fetal

Maternal measles or rubella often causes

deafness

Smoking decreases the amount of oxygen may

lead possible brain damage to a smoking mother

infant

Harmful Effects on Nervous System


35/40

Aged

Orthostatic hypotension A type of low blood pressure resulting from changes in

body position

Arteriosclerosis and high blood pressure

Decreases supply of oxygen to brain neurons which if

gradual may lead to senility, characterized by

forgetfulness, irritability, difficulty in concentrating and

thinking clearly and confusion


36/40

Alzheimers Disease

Progressive degenerative braindisease

Mostly seen in the elderly, but may

begin in middle age Structural changes in the brain

include abnormal protein deposits

and twisted fibers within neurons

Victims experience memory loss,

irritability, confusion and ultimately,

hallucinations and death


37/40

Parkinson's Disease

Typical on people in their

50s and 60s

Dopamine-releasingneuron degeneration

Causes overactiveness


38/40

Huntingtons Disease

Strikes middle age which leads to massive

degeneration of the basal nuclei and later of

the cerebral cortex

Symptoms are wild, jerky and almost

continuous flapping movements

Mental deterioration occurs

Essentially symptoms of huntingtons disease is

the opposite of parkinsons disease


39/40

Cerebrovascular Accident (CVA)

Commonly called a stroke

The result of a ruptured blood vessel

supplying a region of the brain Brain tissue supplied with oxygen from that

blood source dies

Loss of some functions or death may result


40/40

Traumatic Brain Injuries

Concussion

Slight brain injury

No permanent brain damage

Contusion

Nervous tissue destruction occurs

Nervous tissue does not regenerate

Cerebral edema

Swelling from the inflammatory response

May compress and kill brain tissue

Documents

nerbyos sistem