Nervous Tissue Flashcards
What is the function of the nervous system
It is the control center of the body
Sensory input
Receptors are sensory structures that Detect stimuli
Stimulus changes in body or environment
What can Sensory receptors monitor the body and the environment for
For stimuli and transmits information to spinal cord and brain
Integration
Spinal cord and brain processes information and determines the appropriate response
Motor output
Motor nerves sense commands to affect or tissues or organs
Central nervous system
Brain and spinal cord
Peripheral nervous system
Cranial nerves and spinal nerves
Sensory division aka afferent division
Signal conduction towards central nervous system
Sensory nerves carry signals from receptors to spinal cord and brain
Somatic sensory division
Receive signals from skin, body wall, and limbs
Visceral sensory division
Internal organs
Receives signals from thoracic and abdominal visceral
Motor Division a.k.a. Efferent division
Signal conduction away from Cns
Motor neurons carry signals to CNS to the Effectors
Somatic motor division
Transmit signal CNS To skeletal muscle
Voluntary nervous system produces voluntary muscle contraction
Visceral motor division
Autonomic nervous system / Involuntary
Transmits signals CNS To cardiac and smooth muscles
Sympathetic nervous system
Fight or flight
gets body ready for activity
Parasympathetic nervous system
Rest and digest
conserves energy
Neurons
Cells that Conduct electrical impulses
Function = neurotransmission
Neuroglia
Cells that support neurons
Neurotransmission
Generation and conduction of electrical signals throughout the body
Action potential
Electrical signals the neuronal cell membrane
What are some properties of neurons
Neurons exhibit longevity
Neurons do not divide
Neurons have exceptionally high metabolic rate
What are the components of A neuron
Soma, cell membrane, dendrites, axon, axon hillock, myelin sheath, nodes of ranvier and axon terminal
Soma
Single central nucleus surrounded by cytoplasm and usual organelles

Nissl bodies
Chromatphillic substances are large clusters of rough endoplasmic reticulum and free ribosomes that stain well with basic dyes
Cell membrane
Can receive signals from other neurons
Dendrites
Short extensions of soma
Receive signals and conduct them towards Soma
Axon
Nerve fiber
single line extension from soma
Axon hillock
Origen of axon from soma
help generate action potential
Myelin sheath
Fat and white covering of axon
insulate signal conduction along axons Which greatly speeds of transmission
Nodes of ranvier
Small unmyelinated gaps of axon
In myelinated axons action potential jumps from node to node which speeds of transmission
Axon terminal
End of axons that participate synapse
Synapse
Connection of axon terminals of a neuron and target cell
Neuroglia
Glia cells Can undergo mitosis
Support neurons
Most cancers in the brain originate from glia cells and referred as gliomas
Astrocytes
Star shaped glia cells with multiple projections
Control chemical environment around neurons which is critical for neural transmission
Form part of blood brain barrier
What is blood brain barrier
A protective membrane around central nervous system to help prevent spread an infection
Microglia
Small cell bodies with multiple cell projections
Ingest foreign material
they are phagocytes and are derived from blood monocytes/macrophages
Ependymal cells
Form simple epithelium that lines cavities of the brain and ventricles
Cerebrospinal fluid
Oligodendrocytes
Cells with fewer projections
form myelin on central nervous system axons
Segments of myelin are formed by Oligodendrocytes projections that are flatten and rolled to layers around CNS axon
Neuroglia of PNS
 Satellite cells
Surround neural soma
Schwann cells
For myelin on PNS axons
Segments of myelin are formed by Schwann cells projections that are flattened and rolled in concentric layers around the PNS axons
Cover Axons of unmyelinated neurons but loosely without node of ranvier
Where are unmyelinated axons found
In autonomic nervous system and in some sensory fibers
Nerves
Collection of nerve fiber in PNS bound together called epineurium 
Components of connective tissue in pns
Endoneurium, perineurium and epineurim
Endoneurium
Loose connective tissue surrounding myelin sheath formed by Schwann cells
Perineurium
Connective tissue surrounding nerve fascicles
Nerve fascicles– Groups of axon bundle together by perineum
Epineurium
Tough outer layer of connective tissue that wraps around a nerve
What do connective tissue that surrounds axons and nerve contain
They contain blood vessels That provide nutrients to axons and Schwann cells
