Chapter 11 Flashcards
Three Functions of the Nervous System
Sensory, Motor, Processing
Two principle parts of the nervous system
CNS, PNS
There are __ cranial nerves
12
There are __ pairs of spinal nerves
31
The central nervous system consists of the _______
Brain and Spinal Cord
The peripheral nervous system consists of the _______
Cranial and spinal nerves
The peripheral nervous system is split into ________ and ___________
Afferent (sensory) and efferent (motor)
Somatic and Visceral send info ______ from the CNS to _________
Away, Skeletal muscles
The Autonomic Nervous system consists of the ________ and ________ divisions
Sympathetic and parasympathetic
Two types of nervous tissue cells are
Neuroglia and Neurons
Four main neuroglia cells of the CNS are _________
Astrocytes, Microglial cells, Ependymal cells, Oligodendrocytes
Astrocytes are the _____ ________ CNS neuroglia
Most abundant
Microglial cells are small, ovoid cells with thorny processes that _____ and _____ neurons.
Touch and monitor
Ependymal cells line ________ fluid-filled cavities
Cerebrospinal
Oligodendrocytes are branched cells. Their processes wrap ___ ______ and form insulating ______ _______
CNS nerve fibers, myelin sheaths in thicker nerve fibers
Two main neuroglia of the PNS are _______ and _________
Satellite and Schwann Cells
The function of satellite cells is to ________
Surround neuron cell bodies in the PNS
The function of Schwann cells is to ______
Surround all peripheral nerve fibers and form myelin sheaths in thicker nerve fibers
Six components of the nerve cell
Dendrites, Body, Axons, Axon Hillock, Myelin Sheath, Schwann Cell
Dendrites are the ________ _________ of a neuron
Receptive region of neuron
Axons are the _______ _______ of a neuron
Conducting region of a neuron
Myelin sheaths function is ________
Protect and electrically insulate an axon as well as increase speed of nerve impulse transmission
A ganglia is a _______
Cluster of neuron cell bodies in the PNS
Myelinated fibers are much _______ than unmyelinated fibers
Faster
Motor neurons look way bigger than ______
sensory neurons
Multipolar neurons have _______ or more processes, most common and major neuron type in CNS
Three
Bipolar neurons have ____ processes consisting of ______ and ________. They are _______
Two (one axon, one dendrite). Rare
Unipolar neurons have one _____ process consisting of two _____
T-like, Axons.
Sensory neurons transmit ______ the CNS
Toward
Motor neurons transmit _____ the CNS
Away from
Interneurons lie between ______ and ______. They shuttle signals through CNS ______ and are mostly entirely within the _______
Motor and sensory. Pathways. CNS.
Neurons have _____ energy. Opposite charges are _______. Highly ______
Potential. Attracted. Excitable
Ohm’s Law is ______
Current = Voltage / Resistance (I = V/R)
Resistance is defined as a __________
Hindrance to charge flow
Current is a flow of _________
Electrical charge between two points
Two main types of ion channels are
Leakage (nongated, always open) and Gated channels.
The three types of gated channels
Chemically (ligand) gated, Voltage-gated, Mechanically gated.
Chemically gated channels open only ___________
With the binding of a specific chemical (e.g. a neurotransmitter)
Voltage-gated channels ____________
Open and close in response to changes in membrane potential
Mechanically gated channels ______
Open and close in response to physical deformation of receptors
Resting membrane potential is approximately -70mV and can vary between
-40 to -90 mV.
What happens during depolarization
Sodium channels open and sodium rushes into the cell
What happens during repolarization
Potassium channels open and potassium rushes out of the cell
What happens during hyperpolarization
Some K+ channels remain open, allowing excess K+ efflux inside of membrane. Becomes more negative
After repolarization what happens
Sodium and Potassium pumps restore ionic conditions
What is the “all or none”
Action potential either happens completely, or does not happen at all
Continuous conduction is _____
Slow conduction that occurs in nonmyelinated axons
Saltatory conduction occurs only in _______ axons and is about __ times faster
Myelinated. 30.
A synapse is a _______
Junction that mediates information transfer
Presynaptic neurons conduct impulses ______ synapse
Toward
Postsynaptic neurons transmit electrical signals _____ from synapse
Away
EPSP (Excitatory Postsynaptic Potential)
Brings the neuron closer to AP threshold. Neurotransmitter binding opens chemically gated ion channels, allows Na+ and K+ to pass simultaneously with Na+ influx greater than K+ efflux.
Temporal Summation
One or more presynaptic neurons transmit impulses in rapid-fire order. First impulse produces EPSP, before it dissipates another EPSP is triggered, stacking on top of eachother.
Spatial Summation
Postsynaptic neuron is stimulated by large number of terminals simultaneously. Many receptors are activated, each produce EPSP’s, which can then add together.
