Exam # 3 Chapter 12 Flashcards
- consists of the brain and spinal cord
- processes many kinds of incoming sensory information
- the source of thoughts, emotions, and memories
- most signals that stimulate muscles to contract and glands to secrete originate here
central nervous system (CNS)
- consists of all nervous tissue outside the CNS
- components are nerves and sensory receptors
peripheral nervous system (PNS)
-bundles of hundreds to thousands of axons plus associated connective tissue and blood vessels that lies outside the brain and spinal cord
nerve
- structure of the nervous system that monitors changes in external or internal environment
- Ex: touch, photo receptors in the eye, and olfactory receptors in the nose
sensory receptors
-the PNS is divided into _____ and _____ divisions
sensory and motor
- the _____ or afferent division of the PNS conveys input into CNS from sensory receptors
- provides the CNS with information about the ____ and _____ senses
sensory division
somatic and special senses
-the _____ senses are tactile, thermal, pain and proprioceptive (where things are in space)
somatic
-the _____ senses are smell, taste, vision, hearing, and equilibrium (balance,ph, pressure senses)
special
- the _____ or efferent division of the PNS conveys output from the CNS to effectors (muscles and glands)
- its further divided into a somatic nervous system and autonomic nervous system
motor division
- conveys output from the CNS to skeletal muscles only
- voluntary action
somatic nervous system (SNS)
- conveys output from the CNS to smooth and cardiac muscles and glands
- involuntary action
autonomic nervous system (ANS)
-the sympathetic, parasympathetic, and enteric nervous system are the main branches of the _____
autonomic nervous system
-the ____ and ____ of the ANS consists of smooth and cardiac muscle and glands
sympathetic and parasympathetic nervous system
-the _____ of the ANA consist of smooth muscle and glands of GI tract
enteric nervous system
-the functions of the nervous system are:
- ____ detects internal and external stimuli
- _____ process info and make decisions
- _____ activate effectors and elicit a response
sensory function
integrative function * also known as integration
motor function
- the ____ is always on
- the _____ responds to changes in environment
parasympathetic
sympathetic
-are the receiving or input portions of a neuron, carry signal to cell body
dendrites
-long, thin cylindrical projection that carry signals away
axons
-prominent clusters of rough ER- materials produced here may be used to regenerate axons in the PNS
nissl bodies
-cone shaped region where axon joins cell body, nerve impulses arise in the trigger zone
axon hillock
-the cytoplasm and plasma membrane of axon
axoplasm
axolemma
-bundles of intermediate fibers, provides the cell with shape and support
neurofibrils
-the dendrites, cell body, and axon is the basic parts of a _____
neuron
-neurons can be classified with 3 ways:
shape, size, and functions
- ______ neurons have several dendrites and one axon
- most neurons of CNS
- all motor neurons
multipolar neurons
- _____ neurons have one main dendrite and one axon
- retina in eye
- inner ear
- olfactory are of brain
bipolar neurons
- _____ neurons have dendrites and one axon that are fused together (pseudo-unipolar)
- sensory receptors
- cell bodies in ganglia
unipolar neurons
- have mossy fibers
- located in the cerebellum, these neurons redulate movement
- intricate series of connections
purkinje cell
- found in the pre-frontal cortex, the home of cognition
- because many other axons can terminate on the dendrites, a single cell can have 30,000 excitatory inputs
pyramidal cell
- sensory neurons (afferent) are found in the ____
- interneuron are found in the _____
motor neurons (efferent) are found in the _____
PNS
CNS
PNS
- make up about half the volume of the CNS
- the glue that holds nervous tissue together
neuroglia
-astrocytes, oligodendrocytes, microglial, and ependymal cells are cells of the _____ system
CNS
- star-shaped, largest and most numerous, many processes that contact neurons, blood capillaries, and pia mater
- contain microfilaments for support
- isolate neurons from harmful substances in blood (blood brain barrier)
- maintain chemical environment fro impulses
- growth, migration, formation of synapses (in embryo as well as learning/memory)
astrocytes
- like astrocytes but smaller, fewer processes
- form the myelin sheath around CNS axons
oligodendrocytes
-small, spiny cells, that function like macrophages (remove debris, microbes)
microglial cells
- single layer of cuboidal/columnar cells
- produce and assist in the circulation of cerebrospinal fluid
ependymal cells
-the cell bodies of most unipolar neurons are located in the _____,(collection on cell bodies) of spinal and cranial nerves
ganglia
- these cells are like oligodendrocytes, but myelinate a single axon or a parallel bundle
- participates in axon regeneration
schwann cells
- flat cell bodies of neurons or ganglia
- support and regulate exchange of material with interstitial fluid
satellite cells
-the two types of cells in the PNS are _____ and _____
schwann cells
satellite cells
-axons surrounded by a multilayered lipid and protein covering called the _____
myelin sheath
-when a axon is _____, the sheath electrically insulates the axon of a neuron and increases the speed of the nerve impulse conduction
myelinated
-axons without a covering are said to be _____
unmyelinated
-the two types of neuroglia that produce myelin sheaths are _____ and _____
schwann cells
oligodendrocytes
- the outer nucleated cytoplasmic layer of the schwaan cell, which encloses the myelin sheath is the _____
- it is found only around axons in PNS
neurolemma
-cluster of neuronal cell bodies located in the PNS
ganglion
-_____ is composed primarily of myelinated axons
white matter
- _____ of the nervous system contains neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, and neuroglia
- it appears grayish because the nissl bodies impart a gray color and there is no myelin in these areas
gray matter
-neurons are electrically excitable and communicate with one another using two types of electrical signals: the _____ and _____
graded potential
action potentials
-_____ potentials are used for short distance communication only
graded potential
-_____ potentials allow communication over long distances within the body
action potential
-an action potential in a muscle fiber is called a _____
muscle action potential
-an action potential that occurs in a neuron is called a _____
nerve action potential
-graded potentials and nerve and muscle action potentials are involved in the relay of sensory stimuli, integrative functions such as _____ and _____
perception
motor activities
- the pathway of _____
- receptor
- sensory neuron
- interneuron
- upper, lower motor neurons
- neuromuscular junction
electrical signals
-the electrical signals produced by neurons and muscle fibers rely on four types of ion channels the _____, the _____, the _____, and the _____
leak channels
ligand gated channel
mechanically gated channel
voltage gated channel
- gated channels that randomly open and close
- found in nearly all cells, including dendrites, cell bodies, and axons of all types of neurons
- passive process
leak channels
- gated channels that open in response to binding of ligand (chemical) stimulus
- dendrites of some sensory neurons such as pain receptors and dendrites and cell bodies of interneurons and motor neurons
- neurotransmitters, passive process
ligand gated channels
- gated channels that open in response to mechanical stimulus such as touch, pressure, vibration, or tissue stretching
- dendrites of some sensory neurons such as touch receptors, pressure receptors, and some pain receptors
mechanically gated channels
- gated channels that open in response to voltage stimulus (change in membrane potential)
- axons of all types of neurons
voltage gated channels
- a anion has a _____ charge
- a cation has a _____ charge
negative
positive
-an electrical potential difference (voltage) that exists across the plasma membrane of an excitable cell under resting conditions
resting membrane potential