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The Nervous System can be divided into
The Nervous System can be divided into
1) Central Nervous System and 2) Peripheral Nervous System
1) Central Nervous System and 2) Peripheral Nervous System
1) Central Nervous system consists of the brain and spinal cord.
Brain
Cerebrum
Cerebellum
Brainstem
Meninges
Spinal Cord
Central Canal
Dorsal/Lateral/Ventral Funiculi
Dorsal/Ventral Horn
2) Peripheral Nervous System consists of Brachial Plexus (Thoracic Limbs) and Lumbosacral Plexus (Pelvic Limbs).
Cerebrum (Brain)
Cerebrum (Brain)
Largest part of the brain
Most anterior area of the brain; cerebral cortex that coordinates the voluntary movements, conscious sensations, and the higher functions of cognition
Surface area is increased via the furrows: Sulci and Gyri
Cerebellum (Brain)
Cerebellum (Brain)
"Little Brain"
works with cerebrum to regulate voluntary actions
Coordinates motor skills e.g. balance, posture, muscle control
Underlies the occipital and temporal lobes of the cerebral cortex
Brainstem (Brain)
Brainstem (Brain)
Main function: connects the cerebrum to the spinal cord and cerebellum
1) Midbrain: functions in vision/hearing (sense)
2) Pons: sleep/wake cycle and breathing
3) Medulla Oblongata: cardiovascular-respiratory system, descending motor tracts, ascending sensory tracts, and cranial nerves
Meninges (Brain)
Meninges (Brain)
Connective tissue coverings of the brain and the spinal cord
3 membrane layers: pia mater, arachnoid, and dura mater
(deep to superficial)
Pia Mater
Pia Mater
deepest; delicate membrane that forms a sheath around the blood vessels and follows the brain and spinal cord into CNS.
Arachnoid
Arachnoid
middle layer; the space between the two layers is bridged by the subarachnoid space, a space full of Cerebrospinal fluid, thus is the site of CSF collection in spinal taps.
Dura Mater
Dura Mater
superficial; tough fibrous outlet covering the CNS. It also forms the falx cerebri, a median fold that separates the cerebral hemispheres.
Epidural Space: space located outside the dura mater and within the spinal canal
Central Canal (Spinal Cord)
Central Canal (Spinal Cord)
Located in the center of the spinal cord
Transports Cerebrospinal Fluid (CSF), extended from fourth ventricle
CSF: circulates and removes metabolic waste from the body
Lined by single layer of columnar ependymal cells
Dorsal/Lateral/Ventral Funiculi (Spinal Cord)
Dorsal/Lateral/Ventral Funiculi (Spinal Cord)
Bundles of nerve fibres
The white matter of the spinal cord divides into dorsal, lateral, and ventral, which are determined by the dorsal and ventral horns of the grey matter.
As the white matter is composed of fatty myelin sheaths of the axons, the funiculis each carry a different function;
Dorsal Funiculi (Sensory tract)
Lateral Funiculi (Sensory and Motor tract)
Ventral Funiculi (Motor tract)
Dorsal/Ventral Horn (Spinal Cord)
Dorsal/Ventral Horn (Spinal Cord)
Nerve cell bodies and interneurons
The gray matter of the spinal cord divides into dorsal, lateral, and ventral horns, and is composed of nerve cell bodies.
Dorsal Horn (location of the sensory synapses)
Lateral Horn (location of the autonomic nervous system)
Ventral Horn (location of motor neuron cell bodies)
Brachial Plexus (PNS)
Brachial Plexus (PNS)
Each thoracic limb is supplied by a brachial plexus, a network of nerves derived from the thoracic nerves.
Suprascapular nerve
Pectoral nerve
Musculocutaneous nerve
Subscapular nerve
Radial nerve
Lumbosacral Plexus (PNS)
Lumbosacral Plexus (PNS)
The right and left lumbosacral plexus supplies nerves to each pelvic limb.
Gluteal nerve
Sciatic nerve
Obturator nerve
Pathology: Bilateral Obturator Nerve Paralysis (dysfunctional hindlimbs)
Tibial nerve
Femoral nerve
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