Intro to Advanced Anatomy 2

nervous system

central nervous system

brain and spinal cord

peripheral nervous system

crainial nerves, spinal nerves, peripheral nerves

distal (downstream)

lesions of the nervous system present where clinically

somatic

receives and responds to info from external environment, innervates skin, bone, joint, and muscle tissues, counscious sensory info from peripheral regions to CNS, motor supply from CNS to voluntary muscles

visceral

receives and responds to info from internal environment, innervates organs, unconscious sensory info to CNS, motor supply to smooth muscle, cardiac muscle, and glands

autonomic nervous system

motor component of the visceral nervous system, homeostatic regulator, 2 integrated divisions

sympathetic nervous system

mobilize body energy stores for increased activity (fight or flight)

parasympathetic nervous system

conserve body energy stores

somites

contain cells that will become skine and skeletal cells

epaxial tissues

cells that will be skin and muscles of back

hypaxial tissues

cells that will become trunk and limbs

neurons

basic functional unit of nervous system, excitable, high metabolic activity, 3 functions

functions of a neuron

receive info, process info, send info

dendrites

short banches extending from neuron cell body, receive and transmit signals to cell body

cell body (soma)

genetic and metabolic center of neuron, small

axon

long extension arising from neuron, carries signals away from cell body, ends in terminal arbor

synapse

junction between neurons, site of signal transmission, chemical transmitters present

myelin

lipid rich membrane surrounding axons, not terminal arbor, insulates axon to increase speed of signal transmission

oligodenrocytes

produce myelin in CNS, provide nutritive support

schwann cells

produce myelin in the PNS

myelin sheath

formed by concentric layers of myelin, divided by small gaps

nodes of ranvier

gaps in myelin sheath, further augment speed

multiple sclerosis

demyelination and loss of oligodendricytes, poorly understood etiology, observable plaques with imaging, varied impairments, episodic with progressive disability

Guillian-Barre syndrome

autoimmune disorder preceded by infection, lesions result of inflammatory attack on myelin sheath, progressive weakness, clinically variable

multipolar neurons

99% of neurons, all motor neurons, variable shape, multiple dendrites, single axon

pseudounipolar neurons

primarily involved in sensory function, single axon splits into peripheral and central branch

nocioception

signaled in responce to tissue threat or damage, not pain

proprioception

awareness of relative position and movement of body parts

bipolar neurons

commonly associated with special senses, processes emanating from opposite ends of cell body, varied function based on location

bipolar neurons in the retina

transmit signals from receptor and output cells in thalamus

bipolar neurons in olfactory system

act as both receptors and output cells

bipolar neurons in vestibular and auditory systems

act as output cells sending info to brainstem

glia

control environment in which neurons function, non-excitable but communicative, multiple functions

functions of glia

facilitate neuron migration and synapse formation in development, shuttle nutrition to neurons, remove waste products, maintain electrochemical surroundings

macroglia

oligodendrocytes and astrocytes

astrocytes

guide developing axons, regulate ionic environment, facilitate reuptake of neurotransmitters, structural support of blood-brain barrier

microglia

immune surveillance in CNS

gray matter

cell bodies within CNS

white matter

axon bundles in CNS

lamina

layers of neuron cell bodies in cerebral and cerebellar cortices

nucleus

compact groups of neuro cell bodies in cerebrum, brainstem, and spinal cord of CNS, containprojection neurons and interneurons

projection neurons

axons connect to other parts of nervous system

interneurons

act as short relays within nucleus

ganglion

compact groups of neuron cell bodies in PNS

tract (fasciculus)

discrete bundle of axons within the spinal cord

column (funiculus)

collection of tracts

lemniscus

term applied to some specific tracts in brain

nerve fiber

axon, myelin sheath (if present), surrounding tissue (PNS)

afferent

convey toward CNS from sense organs and sensory receptors

efferent

convey from CNS to effector organs

somatic sensory afferents

carry signals from receptors in somatic tissues to CNS, multiple sensory modalities

somatic motor efferents

carry signals away from CNS to somatic tissues (skeletal muscle)

visceral sensory afferents

carry signals from receptors in visceral tissues to CNS, multiple sensory modalities

visceral motor efferents

carry signals away from CNS to visceral tissues, synapse with each other within ganglion

sympathetic visceral motor efferents

short pre-ganglionic and long post-ganglionic fibers

parasympathetic visceral motor efferents

long pre-ganglionic and short post-ganglionic fibers

crainial nerves

arise from brain or superior part of spinal cord, exit cranial cavity through various openings in crainium

spinal nerves

combination of a dorsal and ventral nerve root, contain both afferent and efferent fibers, exit vertebral column through intervertebral foramina

peripheral nerves

arise distal to spinal nerves and their divisons

nerve rootlets

small collections of nerve fibers arising from the dorsal and ventral surfaces of spinal cord

nerve roots

combination of rootlets as the travel distal to spinal cord

posterior ramus

supplies structurs of the back

anterior ramus

supplies structures of lateral and anterior trunk and limbs