Importance of understanding fissures and sulci in studying the brain.
White Matter
Composed of myelinated neurons.
Appears white due to the myelin covering.
Gray Matter
Comprised of unmyelinated or slightly myelinated neurons.
Has a grayish appearance.
Quadriceps Femoris Muscle
Key muscle group involved in extension of the knee.
Flexor Muscles
Responsible for bending joints.
Extensor Muscles
Responsible for straightening joints.
Points of communication between neurons and muscles.
Essential for muscle contraction signaling.
Testing the patellar ligament with a reflex hammer activates sensory neurons.
Path of Sensation
Sensory information travels to the posterior horn of gray matter.
Pathway diverges towards the brain for further processing.
Structure of Spinal Nerves
Formed from the union of dorsal roots (sensory neurons) and ventral roots (motor neurons).
Located between vertebrae and organized into three plexuses:
Cervical Plexus
Composed of spinal nerves C1 to C4.
Innervates neck skin and muscles, including the phrenic nerve which controls diaphragm function.
Brachial Plexus
Originates from spinal nerves C5 to T1.
Supplies nerves to shoulders, upper limbs, and hand.
Lumbosacral Plexus
Originates from spinal nerves L1 to S4.
Supplies nerves to lower limbs and parts of the pelvis.
Each spinal nerve, except C1, correlates with specific areas of skin for sensory functions.
Cutanous refers to the skin, indicating the areas supplied by sensory branches.