Sensory/Motor Cells: Chapter 11 Flashcards
Sensory Input
Information that is given to the nervous system that monitors internal or external changes of the body (stimuli)
Afferent
carry nerve impulses from receptors or sense organs towards the central nervous system.
Nervous System
the master controlling and communicating system of the body
Integration
process of nervous system processing & interpreting sensory input to determine what should be done at any given moment.
- Interpret Information
- Form Memory
- Problem Solve
Motor Output/Control
the response the nervous system give out by activating effector organs (muscles and glands)
Effector
A nerve ending that carries impulses to a muscle, gland, or organ and activates muscle contraction or glandular secretion.
Neurons
Excitable cells that transmit electrical signals
Supporting Cells (Glial Cells)
Cells that surround and wrap a neuron.
What do Glial Cells do?
- Provide a supportive network framework for neurons
- Segregate and insulate neurons
- Guide young neurons to their popper connections
- Promote health and growth of neurons
Astrocytes (Structure & function)
Structure: most abundant versatile, and highly branched glial cells… Cling to neurons and their synaptic endings covering Capillaries
Function:
- Support & brace neurons
- anchor neurons to their capillary nutrient supply (blood brain barrier) (blood vessels)
- guide migration of young neurons and helping to determine capillary permeability
- Help control ion & neurotransmitter enviroment/ re-uptake of neurotransmitters at synapses
Microglia (Structure & function)
Structure:
-Small oval cells with thorny process
Function:
-transfers into local microphages that clean up microbes or neuron debries
Ependymal Cells (Structure & function)
Structure:
-range in shape from small ovoid cells that are often ciliated
Function:
- line central cavities of brain & spinal column
- ciliated cells function to move CSF
Oligodendrocytes (Structure & function)
Structure:
-Branched cells that wrap certain nerve fibers, forming insulated covers known as myelin sheaths
What are the two types of neuroglia in the PNS?
Satellite cells & schwann cells
What are the four types of neuroglia of the CNS?
Astrocytes
Microglia
Ependymal
Oligodendrocytes
What is a neuroglia cell?
the supporting or nonneuronal tissue cells of the central and peripheral nervous system. They perform the less specialized functions of the nerve network
Schwann Cell (structure & function)
Structure:
-Surround majority of nerve fibers in PNS, forming myelin sheaths
Function:
- import and regeneration of a damaged nerve
- import and increasing nerve condition speed
- counterpart the oligodendrocytes in CNS
Satellite Cell (structure & function)
Structure:
-surround ganglionic neuron cell bodies
Function:
-counterpart the astrocytes in CNS
Neurons (Structure & Function)
Structure:
- composed of a body, axon, & dendrites
- amitotic (can not be replaced) & have high metabolic rate
Function:
- Plasma membranes function in
- Electrical signals
- cell to cell signals during development
What is the purpose of the Plasma membrane of the neurons?
- electrical signals
- cell to cell signaling during nervous system developement
Nerve Cell Body: other name, structure, funtion
Perikaryon & Soma
Structure:
-spherical nucleus with a conspicuous nucleolus surrounded by cytoplasm
-axon hillock
Function:
-major biosynthetic center of neuron
-Nissl bodies: produces a lot of protein which creates neurotransmitters.
-
Nerve Cell Processes: how many kinds? other name? structure?
Dendrites & Axons
Structure:
-Arm like extensions from soma
Dendrites of Motor Neuron
short, tapered, diffusely branched processes
- receptive input regions of neuron
- electrical signals conveyed as graded potentials
Axons of Motor Neruon
slender processes arising from axon hillock
-unusually only one uni-branced axon per neuron
Axon Terminal
end of axon (aka branched terminus of an axon
Multi branched axon
Nodes of Ranvier
Track
bundles of axon in CNS
Nerves
bundles of axons in PNS
What is the function of an Axon?
- generate & transmit action potentials
- secrete neurotransmitters from axons
- move substance along axons
Anterograde
movement toward axonal terminal (all electrical signals –going towards receptors at end)
Retrograde
Away from axon terminal
-important because it advises the cell body of conditions at axon terminal
Axon Hillcok
initial cone-shaped area of axon where it arises from
Myelin Sheath
Whitish, fatty (protein lipid) wrapped around most axons
- protects axon
- electrical insulate fibers from one another (so signal does not jump)
- increases speed of nerve impulse transmission
Nodes of Ranvier
~1um gaps in myelin sheath between adjacent Schwann cells (~1mm apart)
un-myelinated axons
- conduct nerve impulses slowly
- some nerve cells that the schwann cell surrounds the axon but coiling does not take place.
- schwann cell may partially enclose 15+ axons
Axons in CNS
-have both mylin and un-myelinated fibers
Oligodendrocytes
- form myelin sheaths in CNS
- has a process that does the wrapping; it can wrap 50+ axons at a time
- it has no NEURILEMMA, has a cell process that does the wrapping (instead of cell itself)
White Matter (CNS)
dense collections of myelinated fibers
Gray Matter (CNS)
nerve cell bodies and un-myelinated fibers
Multipolar
three or more process from an axon; most abundant
Bipolar
two processes; 1 axon & 1 dendrite (found in special sense organs)
Unipolar
single short process -satellite cell- (found in dorsal root ganglia of spinal cord)
Sensory Neurons
afferent, transmits signals towards CNS
Motor Neurons
Efferent- transmits signals away from CNS
Interneurons
association neurons; shuttle & connect signals through CNS pathways
