Copy of Week 10 - Nervous System, Spinal Cord, Spinal Nerves

Nervous Tissue

Tissue composed of neurons that transmit electrical signals and supportive cells that protect and assist in the functioning of neurons.

Central Nervous System

The brain and spinal cord, which are enclosed by the cranium and vertebral column, respectively.

Peripheral Nervous System

The part of the nervous system outside of the brain and spinal cord, including sensory and motor neurons.

Endocrine System

The system of glands that secrete hormones into the bloodstream for long-distance communication and regulation of bodily functions.

Neurons

Nerve cells that have the properties of excitability, conductivity, and secretion, and are responsible for transmitting electrical signals in the nervous system.

Sensory Neurons

Neurons that detect stimuli and transmit information from receptors to the central nervous system.

Motor Neurons

Neurons that send signals from the central nervous system to muscles and gland cells to carry out responses.

Myelin Sheath

Insulation around nerve fibers formed by glial cells, such as oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system.

Blood-Brain Barrier

A tightly packed layer of cells that line the blood vessels in the brain and spinal cord, preventing large molecules, immune cells, and disease-causing organisms from entering the central nervous system.

Spinal Cord

The information highway that connects the brain with the lower body, responsible for conduction, neural integration, locomotion, and reflexes.

Columns (funiculi)

Subdivisions of the spinal cord consisting of posterior (dorsal), lateral, and anterior (ventral) columns.

Peripheral Nervous System

Divided into sensory and motor divisions, each with somatic and visceral subdivisions. Composed of nerves, ganglia, and plexuses.

Nerve

Cord-like organ composed of nerve fibers bound together by connective tissue. Can be mixed nerves containing both afferent and efferent fibers.

Epineurium

The outermost connective tissue wrapping of a nerve.

Ganglion

A cluster of neuron cell bodies outside the CNS, enveloped with epineurium and containing bundles of nerve fibers.

Dorsal Root Ganglion

Swelling formed by the cell bodies of sensory neurons located on the posterior (dorsal) root of a spinal nerve.

Rami of the Spinal Nerves

Anterior and posterior branches of spinal nerves. Anterior rami form plexuses, while posterior rami innervate muscles, joints, and skin of the back.

Spinal Nerve Plexuses

Networks formed by the branching and merging of spinal nerves, except in the thoracic region. Includes cervical, brachial, lumbar, sacral, and coccygeal plexuses.

Cervical Plexus

Receives fibers from the anterior rami of nerves C1-C5 and gives rise to important nerves such as the phrenic nerve.

Brachial Plexus

Innervates the upper limb and some muscles of the neck and shoulder. Includes nerves such as the median, ulnar, and radial nerves.

Lumbar Plexus

Innervates the abdominal wall, anterior thigh, and genitalia. Composed of five roots and two divisions.

Sacral and Coccygeal Plexuses

Innervate the remainder of the lower trunk, lower limb, and pelvic region. Includes nerves such as the sciatic nerve and pudendal nerve.

Dermatome

Specific area of skin that sends sensory input to a specific spinal nerve. Can be used to assess spinal nerve damage.