Lecture 17

Front 1

Spinal Meninges

Back 1

Cover spinal nerves up to the exit point from the spinal column through the inervertbral foramina

Front 2

Cerebrospinal Fluid

Back 2

Shock absorver & suspension system for the spinal cord & brain

Front 3

Denticulate Ligaments

Back 3

thickenings of the pia mater that project and fuse with the arachnoid mater & inner surface of the dura mater between the anterior & posterior nerve roots of spinal nerves on either side

Front 4

The Dura Mater

Back 4

composed of dense, irregular connective tissue (the most superficial of the 3 spinal meninges)

Front 5

The Epidural Space

Back 5

a space between the dura mater and the wall of the vertebral canal (contains a cushion of fat and connective tissue to protect the spinal cord)

Front 6

The Arachnoid

Back 6

An avascular covering that is a spider-web arrangement of delicate collagen fibers & some elastic fibers (the middle menix)

Front 7

Subdural Space

Back 7

contains interstitial fluid (located between the dura mater and the arachnoid mater)

Front 8

The Pia Mater

Back 8

A thin transparent connective tissue layer that adheres to the surface of the spinal cord and brain (the inner-most meninx

Front 9

Length of an adult spinal cord

Back 9

42-45 cm (16-18 in)

Front 10

Diameter of a spinal cord

Back 10

2 cm (.75 in) in the midthoracic region

Front 11

The Cervical Enlargement

Back 11

Extends from the 4th cervical vertebrae to the 1st thoracic vertebra

Front 12

Lumbar Enlargement

Back 12

Inferior enlargement extending frmo the 9th to the 12th thoracic vertebra

Front 13

Conus Medullaris

Back 13

Concical structure inferior to the lumbar enlargement where the spinal cord terminates in a tapering (ends at the level of the intervertebral disc between the 1st and 2nd lumbrar vertebrae in adults)

Front 14

Filum teminale

Back 14

arises from the conus medullaris

Front 15

The anterior median fissure

Back 15

a wide groove on the anterior (ventral) side of the white matter of the spinal cord

Front 16

Posterior Median Sulcus

Back 16

Narrow groove on the posterior side of the white matter of the spinal cord

Front 17

Gray Matter

Back 17

Consists of cell bodies of neurons, neuroglia, unmyelinated axons and the dendrites of interneurons and motor neurons (shaped like a H and surrounded by white matter)

Front 18

White Matter

Back 18

Consists of bundles of myelinated axons of sensory neurons, interneurons and motor neurons

Front 19

Gray commissure

Back 19

forms the crossbar of the H

Front 20

Central canal

Back 20

center of the spinal cord, extends the entire length of the spinal cord and contains cerebrospinal fluid

Front 21

horns

Back 21

gray matter on each side of the spinal cord

Front 22

Anterior gray horns

Back 22

contain somatic motor nuclei

Front 23

Somatic motor nuclei

Back 23

clusters of cell bodies of somatic motor neurons that provide nerve impulses for contraction of skeletal muscles

Front 24

Posterior gray horns

Back 24

contain all bodies and axons of interneurons as well as axons of incoming sensory neurons

Front 25

Lateral gray horns

Back 25

present only in the thoracic, upper lumbar, and sacral segments of the spinal cord; contain cell bodies of autonomic motor nuclei

Front 26

Autonomic motor nuclei

Back 26

regulate activity of smooth muscle, cardiac muscle and glands

Front 27

Anterior white commissure

Back 27

connects the white matter of the right and left sides of the spinal cord (anterior to the gray commissure)

Front 28

Spinal Nerves

Back 28

Spinal nerves and the nerves that branch from them are part of the PNS; connect the CNS to sensory receptors, muscles and glands in all parts of the body

Front 29

# pairs of spinal nerves

Back 29

31 pairs (each pair arises from the spinal cord). 8 pairs of cervical, 12 pairs of thoracic nerves, 5 pairs of lumbar nerves, 5 pairs of sacral nerves & 1 pair of coccygeal nerves

Front 30

Spinal nerve trunk

Back 30

a mixed nerve coposed of the convergence of sensory posterior root and motor anterior root that project laterally from the spinal cord

Front 31

Spinal nerve trunk

Back 31

runs a short distance before branching into 2 large branches and a variable series of smaller branches

Front 32

Ramus

Back 32

each large branch

Front 33

Anterior/Posterior Ramus

Back 33

Somatic branches that run in the musculoskeletal system

Front 34

Posterior Ramus

Back 34

Serves deep muscles and skin of the posterior surface of the trunk

Front 35

Anterior ramus

Back 35

serves the muscles and structures of the upper and lower limbs and the muscles and skin of the lateral and anterior regions of the trunk

Front 36

Smaller visceral branches

Back 36

Form the autonomic pathways to smooth muscle and glandular tissue (like the meningeal branch and communicating rami)

Front 37

Plexus

Back 37

Groups of nerves emerge from plexuses

Front 38

Principal Plexuses

Back 38

Cervical, brachial, lumbar, sacral and coccygeal plexus

Front 39

The sacral plexus

Back 39

anterior rami of spinal nerves L4-L5 and S1-S4; situated anterior to the sacrum; supplies the buttocks, perineum and lower limbs.

the sciatic nerve arises from the sacral plexus

Front 40

coccygeal plexus

Back 40

formed from coccygeal nerves

Front 41

Dermatomes

Back 41

Areas of skin that provide sensory input to the CNS via one pair of spinal nerves; nerve supply in adjacent dermatomes overlap

Front 42

Advantage of Dermatomes

Back 42

make it possible to locate damaged regions of spinal cord by knowing their corresponding spinal cord segments

Front 43

Nerve Fiber

Back 43

formed by the axon and associated glial cells

Front 44

Endoneurium

Back 44

each nerve fiber sits in a loose connective tissue; it consists of a mesh of collagen fibers, fibroblasts and macrophages surrounded by endoneurial fluid (extracellular fluid) derived from the capillaries

Front 45

Perineurium

Back 45

thicker sheath of connective tissue, packages groups of nerves into bundles called fasciculi; consists of collagenous sheaths with up to 15 layers of fibroblasts distributed in a meshwork of collagen

Front 46

Reflex

Back 46

fast, involuntary, unplanned sequence of actions that occurs in response to a particular stimulus (some are inborn and others are acquired)

the spinal cord promotes homeostasis by serving as an integrating center for some reflexes

Front 47

Spinal reflex

Back 47

when integration takes place in the spinal cord gray matter

Front 48

Cranial Reflex

Back 48

when integration occurs in the brain stem rather than spinal cord

Front 49

Somatic Reflexes

Back 49

contraction of skeletal muscles

Front 50

Autonomic reflexes

Back 50

generally are not consciously perceived

Front 51

Sensory Receptor

Back 51

responds to a specific type of stimulus by generating one or more nerve impulses

Front 52

Sensory neuron

Back 52

nerve pules conduct from sensory receptor along axion of a sensory neuron to its axon terminals; located in the CNS gray matter. axon brances relay nerve impulses to the brain and allows concious awareness that the reflex has occured

Front 53

integration center

Back 53

one or more regions of gray matter in the CNS that acts as an integrating center

Front 54

motor neuron

Back 54

impulses triggered by the integrating center pass out of the spinal cord along a motor neuron to the part of the body that will respond

Front 55

effector

Back 55

part of the body that will respond to the motor nerve impulse, such as a muscle or gland