10: Nervous tissue Flashcards
What do CNS and PNS stand for?
Central nervous system
Peripheral nervous system
Is sensory information afferent or efferent?
Afferent
Is motor information afferent or efferent?
Efferent
What 3 kinds of senses contribute to sensory information?
Special senses
Somatic senses
Visceral senses
What constitutes the special senses?
Vision, hearing, taste, smell, balance/equilibrium
What constitutes the somatic senses?
Information from skin, joints, and skeletal muscles
What constitutes the visceral senses?
Information from internal organs and blood vessels
What are the two branches contribute to the efferent motor information?
Somatic nervous system
Autonomic nervous system
What constitutes the somatic nervous system?
Voluntary muscles
Innervates skeletal muscle
What constitutes the autonomic nervous system?
Involuntary muscles
Innervates cardiac muscle, smooth muscle, and glands
What are the components of nervous tissue?
Neurons
Glial cells
Microglial cells
Astrocyte
Oligodendrocytes
Ependymal cells
What are neurons?
Excitable cells that transmit nerve impulses
What are glial cells?
Non-excitable cells that support and protect the neurons
More abundant than neurons
What is the name of the cell body of a neuron?
Soma
What is the part of a neuron where the electrical signal is initiated?
Axon Hillock
Towards what neuron organelle does an electrical impulse always travel?
Toward the axon terminals
In relation to the nervous system, what is integration?
The processing of stimuli and comparing it with other stimuli, memories of previous stimuli, or state of a person at a specific time
What is the term that means dendrites and axons?
Neurites
What neuron organelle houses the receiving end of a synapse?
Dendrites
What protective covering do many axons have?
Myelin sheath
What kind of cells form myelin?
Glial cells (oligodendrocytes)
What part of the neuron houses the transmitting synapses?
Axon terminals
What information do unipolar neurons transmit?
Sensory
What are the two unique characteristics of a unipolar neuron?
- Dendrites are sometimes receiving sensory information directly from the stimulus
- Cell bodies are always found in ganglia
What information do bipolar neurons transmit?
Sensory info from the special senses
What is the small space between the the membranes of the presynaptic neuron and the postsynaptic neuron?
Synaptic cleft
What do astrocytes do? Which system are they part of?
Control ionic movement
Induce formation of the blood-brain barrier
Part of CNS
What do oligodendrocytes do?
Form the myelin sheaths in CNS
What do microglial cells do? Which system are they part of?
Clean up debris and fight infection
Can engulf foreign objects like WBC
Part of CNS
What do ependymal cells do?
Line brain internal cavities (the ventricles)
The choroid plexus is where these come in contact with blood vessels. The ependymal cells filter and absorb components of the blood to produce CSF
What do schwann cells do?
Myelinate PNS axons
What do satellite cells do?
Protect and regulate nutrients for neuron cell bodies in ganglia
What is the structure of myelin?
White, fatty coating around axons
What is the name of the spaces in the myelin sheath? What purpose do they serve?
Nodes of Ranvier
Speeds up electrical impulses by creating “stepping stones” for the current
What does gray matter contain?
Neuron cell bodies and dendrites
What does white matter contain?
Axons and myelin sheaths
Where in the PNS are neuron cell bodies and dendrites found?
Ganglia
Where in the PNS are axons found?
Nerves
What neurons form the ganglia of the PNS directly off the spinal cord?
Unipolar sensory neurons
What neurons form the anterior rootlets?
Efferent motor neurons
What neurons form the posterior rootlets?
Afferent sensory neurons
What is the fibrous connective tissue of the outer layer of a nerve?
Epineurium
What fibrous connective tissue forms the fascicles within nerves?
perineurium
What loose connective tissue covers the axons within a nerve?
endoneurium
Where is the cell body of a secondary motor neuron?
Gray matter of the spinal cord
What does an interneuron do?
It carries sensory information received to other parts of the brain for reaction
What organelle does Multiple Sclerosis affect? What is the result?
Affects oligodendrocytes
Results in patches of myelin in brain and spinal cord being destroyed
