Chapter 13
Lumbar Enlargement
Area of the spinal cord from which nerves to and from the lower limbs arise
Meningeal Branch
Spinal nerve branch that supplies vertebrae, vertebral ligaments, blood vessels of the spinal cord, and meninges
Anterior (ventral) Ramus
Spinal nerves branches that serve the muscles and structures of the upper and lower limbs and the lateral and ventral trunk
Dura Mater
Superficial spinal cord covering of dense, irregular connective tissue
Coccygeal Plexus
Supplies a small area of skin in coccygeal region
Sacral Plexus
Supplies the buttocks, perineum, and lower limbs
Reciprocal Innervation
a neural circuit that coordinates body movements by causing contraction of one muscle and relaxation of antagonistic muscles or relaxation of a muscle and contraction of the antagonists
Crossed Extensor Reflex
A balance-maintaining reflex
Flexor (withdrawal) Reflex
Polysynaptic reflex initiated in response to a painful stimulus
Anterior (ventral) Root
Contains motor neuron axons and conducts impulses from the spinal cord to the peripheral organs and cells
The connective tissue surrounding each individual axon is:
Endoneurium
Contralateral Reflex Arc
Sensory impulses enter on one side of the spinal cord and motor impulses exit of the opposite side
Central Canal
Space within the spinal cord filled with cerebrospinal fluid
Gray matter of the spinal cord contains somatic motor and sensory nuclei, autonomic motor and sensory nuclei, and functions to receive and integrate both incoming and outgoing information.
True
Stretch Reflex
A reflex resulting in the contraction of a skeletal muscle when it is stretched
Stretch Reflex
Acts as a feedback mechanism to control muscle length by causing muscle contraction
Filum terminale
An extension of the pia mater that anchors the spinal cord to the coccyx
Cervical Enlargement
Area of the spinal cord from which nerves to and from the upper limbs arise
Arachnoid Mater
Avascular covering of spinal cord composed of delicate collagen fibers and some elastic fibers
Posterior (dorsal) Root
Contains sensory neuron axons and conducts impulses from the peripheral receptors into the spinal cord
Denticulate Ligaments
Extending the length of the spinal cord, these pia mater thickenings fuse with the arachnoid mater and dura mater and help to protect the spinal cord from shock and sudden displacement
The epidural space is located between the wall of the vertebral canal and the pia mater.
False
Lumbar Plexus
Femoral nerve arises from this plexus
Coccygeal Plexus
Formed by anterior rami of S4-S5 and coccygeal nerves
Cervical Plexus
Formed by the anterior rami of C1-C4 with some contribution of C5
Brachial Plexus
Formed by the anterior rami of C5-C8 and T1
Lumbar Plexus
Formed by the anterior rami of L1-L4
Sacral Plexus
Formed by the anterior rami of L4-L5 and S1-S4
Cervical Plexus
Injury to this plexus can affect breathing
Cutting the posterior root of a spinal nerve would:
Interfere with the flow of sensory impulses
Example of a motor tract?
Lateral Corticospinal
Stretch Reflex
Maintains proper muscle tone
Brachial plexus
Median nerve arises from this plexus
Because they contain both sensory and motor axons, spinal nerves are considered to be _____ nerves.
Mixed
Ipsilateral Reflex Arc
Motor nerve impulses exit the spinal cord on the same side that sensory impulses entered the spinal cord
Intersegmental Reflex Arc
Occurs when sensory nerve impulse travels up and down the spinal cord, thereby activating several motor neurons and more than one effector
Tendon Reflex
Operates as a feedback mechanism to control muscle tension by causing muscle relaxation when muscle force becomes too extreme
Cervical Plexus
Phrenic nerve arises from this plexus
Tendon Reflex
Protects the tendon and muscle from damage due to excessive tension
Brachial Plexus
Provides the entire nerve supply of the shoulders and upper limbs
Lumbar Plexus
Provides the nerve supply of the anterolateral abdominal wall, external genitals, and part of the lower limbs
Cervical Plexus
Provides the nerve supply of the skin and muscles of the head, neck, and superior part of the shoulders and chest
Muscle Spindles
Receptors that monitor changes in muscle length
Tendon (Golgi tendon) Organs
Receptors that monitor changes in muscle tension
Monosynaptic Reflex
Reflex arc that consists of one sensory and one motor neuron
Polysynaptic Reflex
Reflex pathway that contains sensory neurons, interneurons, and motor neurons
Sacral Plexus
Sciatic nerve arises from this plexus
The five components of a reflex arc, in order from the beginning to the end, are:
Sensory receptor, sensory neuron, integrating center, motor neuron, effector
Posterior (dorsal) Ramus
Spinal nerve branches that serve the deep muscles and skin of the posterior surface of the trunk
The following are true:
The anterior (ventral) gray horns contain cell bodies of neurons that cause skeletal muscle contraction, Cell bodies of autonomic motor neurons are located in the lateral gray horns, and Gray matter in the spinal cord consists of cell bodies of neurons, neuroglia, unmyelinated axons, and dendrites of interneurons and motor neurons.
Plexus
The joining together of the anterior rami of adjacent nerves
Cauda Equina
The roots form the nerves that arise from the inferior part of the spinal cord but do not leave the vertebral column at the same level as they exit the cord
Pia Mater
Thin transparent connective tissue composed of interlacing bundles of collagen fibers and some elastic fibers adhering to the spinal cord's surface
The tracts of the posterior column are involved in:
conscious proprioception, touch, pressure, and vibration