spinal code

cervical region

(C1-C8)This region is responsible for innervating the neck, shoulders, arms, and hands. It plays a crucial role in motor control and sensory perception for the upper body.

thoracic region

(T1-T12)This region innervates the chest and abdominal muscles. It is involved in the control of the trunk and the autonomic functions of the body.

lumber region

(L1-L5)This region is responsible for innervating the lower back, hips, and legs. It plays a significant role in motor control and sensory perception for the lower body.

Sacral Region

This region innervates the pelvic organs and lower limbs. It is crucial for functions related to bowel, bladder, and sexual function.

medullary cone

is the tapered, cone-shaped terminal end of the spinal cord. In adults, it is typically located between the L1 and L2 vertebrae,

Motor/sensory for lower limbs, pelvis, perineum; parasympathetic for pelvic organs

Cauda equina

Below L1, in lumbar cistern

Motor, sensory, and parasympathetic innervation to lower limbs, pelvis, and perineum

Filum terminale

From conus tip to coccyx

Anchors and stabilizes the distal spinal cord

spinal tap

A spinal tap, also called a lumbar puncture (LP), is a medical procedure in which a needle is inserted into the lower back, into the space between two lumbar vertebrae, to collect a small sample of cerebrospinal fluid (CSF) for testing or to measure its pressure

low risk, cause needle cant reach spinal code, the needle is made to be less trauma into the back.

gray matter for spinal code

the core of the nerve. has axon, dendrites, and glial cells. it has horns.

white matter of the spinal code

outer side of the code. has columns

ganglion

PNS. Ganglia serve as relay stations for sensory or autonomic signals.

Nucleus

A nucleus is a group of neuron cell bodies. CNS. ex/ hypothalamic

Nerve

bundle of axon in the PNS. ex/ Optic nerve, Sciatic nerve

Tract

bundle of axon in CNS that transmit info. ex/ spinothalamic tract

Dorsal root

Contain afferent (sensory) fibers that carry information from the periphery (skin, muscles, joints) into the spinal cord.

Ventral root

Contain efferent (motor) fibers that carry motor commands from the CNS to skeletal muscles

Dorsal Root Ganglion

• Neurons are first-order somatosensory neurons that detect touch, vibration, proprioception, pain, and temperature.

Spinal Nerve Formation

• Spinal nerves exit the vertebral canal via intervertebral foramina.

• They are mixed nerves (somatic motor, sensory, and autonomic fibers) that connect the CNS to the periphery

Dorsal ramus

• Supplies motor innervation to deep (intrinsic) back muscles and sensory innervation to skin of the posterior head, neck, and back.

ventral ramus

• Supplies motor innervation to most trunk and limb muscles and sensory innervation to skin of the anterior and lateral trunk and limbs.anterior of spinal nerve

Endoneurium

Provides insulation and support to the axon, and contains endoneurial fluid—a low-protein liquid similar to cerebrospinal fluid in the CNS—that bathes the axon and helps maintain a blood-nerve barrier. covers each indivisual axon

Perineurium

Protects the fascicle, regulates its internal environment, and contributes to the blood-nerve barrier.

Epineurium

: Provides structural support, cushions the nerve against mechanical injury, and supplies nutrients to the inner layers.

entire nerve

Ascending tract

Ascending tracts are responsible for transmitting sensory information from peripheral receptors to higher brain centers for processing, including touch, pain, temperature, vibration, and proprioception

so send twords brain.

First-order neurons

Located in the dorsal root ganglion, receive input from sensory receptors.

Second-order neurons

Found in the dorsal horn of the spinal cord or brainstem; their axons often decussate (cross to the opposite side).

Third-order neurons

Located in the thalamus, projecting to the primary sensory cortex for conscious perception

Dorsal column-medial lemniscus system

Carries fine touch, vibration, and proprioception.

Spinothalamic tracts

Transmit pain, temperature, and crude touch.

Spinocerebellar tracts

Convey unconscious proprioception to the cerebellum for coordination
Found in the white matter of the spinal cord, organized into dorsal, lateral, and anterior funiculi

Descending tracts

Descending tracts carry motor commands from the brain to the spinal cord, controlling voluntary and involuntary movements

twords muscle

Upper motor neurons

Originate in the motor cortex or brainstem and project to lower motor neurons.

Lower motor neurons

Located in the anterior horn of the spinal cord; directly innervate skeletal muscles

Corticospinal tracts

• Control voluntary fine motor movements.

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Rubrospinal, reticulospinal, vestibulospinal, and tectospinal tracts

• Rubrospinal, reticulospinal, vestibulospinal, and tectospinal tracts: Regulate posture, balance, and reflexive movements

Found in the white matter of the spinal cord, primarily in lateral and anterior funiculi

somatic reflex

receptor, sensory neuron, interneuron, motor neuron, and effector, which work together to produce a rapid, involuntary skeletal muscle response.

monosynaptic

single synapse

polysynaptic

multiple synapses

Muscle spindles

Muscle spindles are encapsulated stretch receptors located within the belly of skeletal muscles, running parallel to the main muscle fibers