Post on 15-Apr-2017
NERVOUS SYSTEMDr. Shabana AliIIMC
Divisipn Meninges
INTRODUCTION
Nervous system is divided Anatomically into:
1. Central Nervous System.2. Peripheral Nervous System.
Functionally it is divided into:1. Somatic Nervous System .2. Autonomic Nervous System .
1.Central nervous system
1.Brain and 2.spinal cord
Parts of brain Forebrain or prosencephalon Midbrain or mesencephalon Hindbrain or rhombencephalon
INTRODUCTION
Parts of hindbrain▪ Pons▪ Medulla oblongata▪ Cerebellum
2.spinal cord Starts at foramen
magnum and ends at L2 level.
2.Peripheral nervous system Twelve pairs of cranial nerves Thirty one pairs of spinal nerves
▪ Cervical – 8▪ Thoracic – 12▪ Lumbar – 5▪ Sacral – 5▪ Coccygeal – 1
Composition of a spinal nerve▪ Sensory fibres▪ Motor fibres▪ Autonomic fibres
Peripheral nervous system
Brain stemCranial nerves
Spinal cord
Coverings of the brain(Dap ) Dura mater---outermost Arachnoid mater---middle S2
LEVEL Pia mater---innermost----coccycx
Also cover the spinal cord after passing through foramen magnum
DURAL FOLDS
1.Falx cerebri2.Tentorium cerebelli3.Falx cerebelli
DURAL FOLDS
Falx cerebri
VENOUS SINUSES OF BRAIN
DURAL VENOUS SINUSES
LOBES OF THE BRAIN
CEREBRAL LOBES
Central sulcus
parietoocipital sulcus
Lateral sulcus
Cerebral lobes
AREAS IN THE CORTEX
Arteries of the brain
BLOOD SUPPLY OF CEREBRUM Ant cerebral Middle cerebral Post
cerebral
Spinal cord
Foramen magnum to lower border of L1 or upper border ofL2
COVERINGS OF THE SPINAL CORD DURA MATER ARACHNOID
MATER PIA MATER
SECTION THROUGH VERTEBRAL COLUMN
Vertebral body
pedicle
spinelamin
aGrey mater
White mater
Blood supply
Anterior and posterior spinal artery
Components of spinal nerve Ventral ramus and dorsal ramus
Spinal nerve
Divides into anterior and posterior rami Anterior --- -- body nerve plexus Posterior rami—sensory innervation to a
skin segment known as a dermatome
Ventral Roots The ventral (motor) roots consist of efferent fibers that convey output from the spinal
cord.
There are two components: (1) innervate voluntary striated
muscles, (2) influences to involuntary smooth
muscles,cardiac muscle, and glands
Voluntary muscles and spinal nerve root Ventral spinal root Muscles innervated C5–6 Biceps brachii (flexes elbow) C6–8 Triceps brachii (extends elbow) T1–8 Thoracic musculature T6–12 Abdominal musculature L2–4 Quadriceps femoris (knee jerk, patellar tendon
reflex) L5–S1–2 Gastrocnemius (ankle jerk, Achilles tendon reflex
Innervation by posterior ramus Dorsal spinal root Body region innervated C2 Occiput C4 Neck and upper shoulder T1 Upper thorax and inner side of
arm T4 Nipple zone T10 Umbilical girdle zone L1 Inguinal region L4 Great toe, lateral thigh, and
medial leg S3 Medial thigh S5 Perianal region
SECTION THROUGH SPINAL CORD
Autonomic nervous system Two parts
▪ Sympathetic▪ Parasympathetic
Functions of autonomic N S Involuntary Controls activities of heart, smooth
muscles of GIT, blood vessels & glands
Neuron
Smallest functional unit is neuron
It consists of cell body and cell processes
Types of neuron
Unipolar Bipolar Pseudo uni polar Multipolar
BONES AT THE BASE OF THE BRAIN