Embryonic Development Pt 1 (1-31)

Nervous system enables the body to react to ___________ in its _____ and _____ environments

continuous changes, internal, external

Nervous system controls and integrates the various activities of the body such as

circulation and respiration

nervous system is divided structurally into

central nervous system and peripheral nervous system

central nervous system consists of the

brain and spinal cord

peripheral nervous system consists of ______ and _____ the CNS that conduct impulses ___ or ____ from the CNS

nerve fibers, cell bodies outside, to, away

nervous system is divided functionally into

somatic and autonomic nervous systems

The PNS is organized into nerves that connect the __________ with _________ structures (spinal nerves & cranial nerves)

CNS, peripheral

PNS has

afferent and efferent axons

Afferent axons carry info from

peripheral receptors toward CNS

afferent axons transmit information to ___ when the hand touches an object

CNS

efferent axons carry information ____ from ___

away CNS

efferent axons carry ____ commands from ____ to ____ muscles

motor, CNS, skeletal

CNS spinal region is contained within

vertebral column

spinal region extends from ____ (opening at _______ aspect of skull) to level of the ______

foramen magnum, infero-posterior, first lumbar vertebra

CNS: spinal cord: can convey ____ and ____ to the brain

somatosensory, ANS

spinal cord CNS conveys signals from the brain to ___ that directly control movement and ______

neurons, autonomic function

ex of cns spinal cord info process

reflexive movement of limb away from painful stimulus

other regions of CNS

brainstem, cerebellum, thalamus, cerebrum, cerebral hemispheres, frontal, parietal, temporal, occipital, limbic, insular, cerebral cortex

How do the PNS and CNS communicate?

stimuli --> PNS: afferent signal (dorsal horn) --> UMN --> PNS: efferent signal (ventral horn)

lesion

area of damage or dysfunction

sign

evidence of a disease or impairment that can be observed by someone other than the patient (edema and paralysis)

symptom

subjective experience of the patient (fatigue, pain, numbness)

signs and symptoms of lesions of the nervous system depend on

location

formation of neural tube: tube concentric rings: inner layer:

contains somas, somas become grey matter

formation of neural tube: tube concentric rings: outer layer:

contains processes of cells of somas from inner layer, develops into white matter: axons and glial cells

relationship of neural tube to other developing structures: adjacent mesoderm divides into

spherical cell clusters (somites)

somites

bulges on surface of embryo

somites become

mesoderms

3 parts of somites

anteromedial part, posteromedial part, lateral part

relationship of neural tube to other developing structures: anteromedial part:

sclerotome, becomes vertebrae and skull

relationship of neural tube to other developing structures: posteromedial part:

myotome, becomes skeletal muscle

relationship of neural tube to other developing structures: lateral part:

dermatome, becomes dermis

inner layer of the neural tube differentiates into

motor plate (ventral) and association plate (dorsal)

changes occur when neurons connect neural tube and somite:

neural plate -->

spinal cord

changes occur when neurons connect neural tube and somite: motor plate -->

ventral horn (motor)

changes occur when neurons connect neural tube and somite: association plate -->

dorsal horn (sensory)

changes occur when neurons connect neural tube and somite: dermatome -->

dermis (sensory)

UMN:

upper motor neuron (CNS)

formation of myotome: axons from somas (grey matter) located in the _____ grow out from the tube to innervate the _____ region of the ______

ventral horn, myotome, somite

myotome

a group of muscles derived from one somite and innervated by a single spinal nerve

myotome has 2 meanings:

1. embryologic section of the somite 2. after embryonic stage - group of muscles innervates by a segmental spinal nerve

Formation of dermatome: axons from somas located in the ______ grow from the tube to innervate the ______ region of the somite

dorsal horn, dermatome

Formation of dermatome: as development continues it leads to the formation of a dermatome which is

an area derived from one somite and innervated by a single spinal nerve

when myotomes become lower motor neurons (LMN)

they innervate skeletal muscle interneurons

neurons in the dorsal region of the neural tube process

sensory information

neurons with somas in the ventral region innervate

skeletal muscle