A Posterior Median Sulcus(Shallow) and an Anterior Median Fissure(Wide).
The Posterior Median Sulcus and Anterior Median Fissure include what? what are they?
The localized enlargements, which are expanded regions where there in increased gray matter to provide innervations of the limbs.
The Spinal Cord extends from what to what?
Formen magnum to L1.
The spinal cord taper to a conical tip which is also know as the?
What is the Filum Terminale?
It is a strand of fibrous tissue that originates at the conical top and extends through the vertebral canal to the second sacral vertebra, ultimately becoming part of the coccygeal and ligament.
The Spinal Cord has how many segments?
All 31 segments of the Spinal Cord are associated with what?
Dorsal Roots Ganglia and paris of Dorsal Roots and Ventral Roots.
What do Dorsal Roots Ganglia contain?
They contain sensory neuron cell bodies.
What are the exceptions in which Dorsal roots are absent?
The first cervical and first coccygeal.
Sensory and motor fibers unite as what?
A single Spinal Nerve distal to each dorsal root Ganglion.
Spinal Nerves emerge from what? why?
Intervertebral foramina and mixed nerves since they contain both sensory and motor fibers.
What is that largest nerve in the body?
The Sciatic nerve
What is the Caudal Equina?
It is the inferior extension of the ventral and dorsal roots and the filum terminale in the vertebral canal.
What are Spinal Meninges?
They are a series of specialized membranes that provide physical stability and shock absorption for neural tissues of the spinal cord.
What are Cranial Membranes?
They are membranes that surround the brain.
What are the three meningeal layers?
1. Dura Mater
2. Arachnoid Mater
3. Pia Mater
What is the Dura Mater? and What does it form
It is the tough, fibrous outermost layer that covers the spinal cord; caudally it forms the coccygeal ligament with the filum terminale.
What does Epidural Space do?
Separates the dura mater from the inner walls of the vertebral canal.
Internal to the inner surface of the dura mater is the?
When the Subdural separates the dura mater from with meningneal layer?
The Arachnoid mater.
Internal to the arachnoid matter is what?
what is the subarachnoid Space?
It is the space that also contains cerebrospinal fluid, which act as a shock absorber and used for spinal tap.
What is the Pia Mater?
The innermost meningeal layer.
Where is the Pia Mater located?
It is bound firmly to the underlying neural tissue.
The ________ are supporting fibers extending laterally from the spinal cord surface, binding the spinal pia mater and arachnoid mater to prevent either side to side or inferior movement of the spinal cord.
Paired Dendiculate ligaments.
The _______ surround the ________ and contains cell bodies of neurons and glial cells.
Central Gray Mater; Central Canal
The Gray mater projections toward the outer surface of the spinal cored are?
What contains myelinated and unmyelinated axons in tracts and columns.
The peripheral white matter.
Neuron cell bodies in the spinal cord gray matter are organized into groups called?
The posterior gray horns contain what?
They contain somatic and visceral sensory nuclei
What is the Anterior Gray Horns involved with?
They are involved with somatic motor control.
What do lateral gray horns contain?
They Contain Visceral Motor neurons
What are Gray commissures?
They are posterior and anterior to the central canal and they contain the axons of interneurons that cross from one side of the cord to the other.
White mater can be divided into how many?
Each of the Six Columns contain what?
Each of them contain tracts
________ relay information from the spinal cord to the brain, and _______ carry information from the brain to the spinal cord.
Ascending Tracts; Descending Tracts.
Which spinal Nerve is what?
Ensheathed by a series of connective tissue layers.
What are the layers of connective tissue of Spinal nerves?
Outermost Layer Epineurium
Middle Layer Perineurium
Inner Layer Endoneurium
What is Epineurium?
It is a dense network of collagen fibers
What is Perineurium?
Partitions the nerve into series of bundles and conveys blood vessels into each individual fibers.
What is Endoneurium?
It is composed of delicate connective tissue fiber that surround individual axon.
What is White Ramous?
The first branch of spinal nerve in the thoracic and upper lumbar regions.
What white ramous contains myelinated axon going to a(n)?
Two groups of unmyelinated fibers exit what ganglion?
What do Gray Ramous do?
They carry axons that innervate glands and smooth muscles in the body wall or limb back to the spinal nerve, and an automatic nerve carrying fibers to internal organs.
Collectively, white and gray matter are called?
Each Spinal nerve has what types of ramuses?
Dorsal and Ventral Ramus.
What it is a Dorsal Ramus?
It provides sensory/motor innervation to the skin and muscles of the back.
What is the Ventral Ramus?
It supplies ventrolateral body surface, body wall structures, and limbs.
Each pair of spinal nerves monitor a region of the body surface called?
A complex, interwoven network of nerves are called?
What are the Four major plexuses?
1. Cervical Plexus.
2. Branchial Plexus.
3. Lumbar Plexus.
4. Sacral Plexus
What does the Cervical Plexus consists of?
It consists of the ventral rami of C1-C4 and some fibers from C5, muscles of the neck are innervated and some branches extend into the thoracic cavity to the diaphragm.
What is the major nerve in the Cervical Plexus?
The Phrenic Nerve
What does the Brachial Plexus consists of?
It innervates the pectoral girdle and upper limbs by the ventral rami of C5-T1.
Where do the nerves of the Brachial Plexus originate?
They originate from cords of trunks: Superior Middle and inferior Trunks give rise to the lateral cord, medial cord, and posterior cord.
Collectively these two plexus originate from the posterior abdominal wall and ventral rami of nerves supplying the pelvic girdle and lower limb.
Lumbar Plexus and Sacral Plexus.
What do Lumbar Plexus contain?
They contain fibers from spinal segments T12-L4
What do sacral plexus contain?
They contain fibers from spinal segments L4-S4
What is Neural reflex?
It is a rapid, automatic, involuntary motor response to stimuli.
Reflexes do what?
Help preserve homeostasis by rapidly adjusting the functions of organs or organ system.
What is a Reflex Arc?
It is the neural "wiring" of the single relex
What is a receptor?
It is a specialized cell that monitors condition in the body or external environment and each receptor ha a characteristic of range of sensitivity.
What are the 5 steps involved in neural reflex?
1. Arrival of a stimulus and activation of a receptor.
2. relay of information to the CNS
3. Information processing
4. Activation of a motor neuron
5. Response by a peripheral effectors.
Reflexes are classified by?
1. Their Development
2. Where information is procesed
3. Motor response
4. Complexity of the neural circuit.
In reflex classification of "Their Development" it split into what?
Innate and acquired
In reflex classification of "Where information is processed" it split into what?
Spinal or Cranial
In reflex classification of "Motor Response" it split into what?
Somatic or visceral
In reflex classification of "Complexity of neural circuit" it split into what?
Monosynaptic or polysynaptic.
How are Innate reflexes determined?
What type of reflex is learned following repeated exposure to a stimulus?
Reflexes processed in the brain are called?
In a _______ the important interconnections and processing occur inside the spinal cord.
What to Somatic Reflex control what?
It controls Skeletal muscle contractions.
What do Visceral Reflexes control?
They control the activities of smooth and cardiac muscle and glands.
What is a Monosynaptic reflex?
It is the simplest reflex arc.
A ________ Synapses directly on ________ that acts as the processing center.
Sensory Neuron ; motor neuron.
This reflex has at least one interneuron places between the sensory afferent and the motor efferent, which is why they have a longer delay between stimulus and response.
What is a Stretch Reflex?
it is a monosynaptic reflex that automatically regulates skeletal muscle length and muscle tone.
What is Spinal Reflexes?
they range from simple monosynaptic reflexes to more complex polysynaptic reflexes.
What is a patellar reflex?
It is the familiar knee jerk, where in a rap on the patellar ligament stretches the muscle spindle in the quadriceps muscle.
What is postural reflex?
It is a stretch reflex that maintains normal upright posture.
What is Quadriplegia?
It is the loss of sensation and motor control of the upper and lower limbs
High Centers of the brain can?
Enhance or inhibit reflex motor patterns based in the spinal cord.