Anatomy - Ch 16 (Neural tissue)
CNS (central nervous system)
brain and spinal cord
nervous system organs
brain, spinal cord, peripheral nerves, sense organs
The afferent division of the PNS __________, while the efferent division of the PNS ______________.
brings sensory information to the CNS; carries motor commands from CNS to effectors.
converging circuit
Many inputs, one output
gray matter
contains neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, and neuroglia
The glial cell that helps to form cerebrospinal fluid is the:
ependymal cell
diverging circuit
one input, many outputs
Neuroglia are ____________. Some examples of neuroglia in the CNS are _________.
Support (framework) and isolate the neurons; Oligodendrocytes, Microglia and Ependymal Cells
microglial cells - CNS
phagocytes
satellite cells - PNS
protect neuron cell bodies; FOUND in dorsal root ganglion (cell bodies of neurons)
Neurology
study of the nervous system
nerve cells
carries impulse away from synapse
glia
cells found throughout the nervous system that provide various types of support for neurons
Neuroglia
cells that support and protect neurons and are smaller than neurons
ependymal cells - CNS
form the blood-cerebrospinal fluid barrier lines cavities of the brain and spinal cord, circulate cerebrospinal fluid
Oligodendrocytes - CNS
form the myelin sheath in the brain and the spinal cord
The axon of the purkinje cells are located in he:
granular cell layer
reverberating circuit
A neural circuit in which a single impulse is transmitted over and over is a ________.
autonomic nervous system
A subdivision of the peripheral nervous system. Controls involuntary activity of visceral muscles and internal organs and glands.
somatic sensory neurons
carries signals from sensory receptors in the skin, muscles, bones, and joints
Parts of a neuron
cell body, dendrites, axon
spatial summation
The sum of multiple synapses firing at different locations at one time to create a net effect
Purkinje cells
a multipolar neuron in the cerebellum, has many branching dendrites, but only one axon
bipolar neurons
a neuron that has only two projections (one axon/one dendrite) from the cell body
chemical synapse
a type of synapse at which a chemical (a neurotransmitter) is released from the axon of a neuron into the synaptic cleft, where it binds to receptors on the next structure (either another neuron or an organ)
white matter
aggregations of myelinated and unmyelinated axons
PNS (peripheral nervous system)
cranial nerves and spinal nerves
depolarization
excitatory (AcH) action potential
sympathetic nervous system
fight or flight
astrocytes - CNS
form blood brain barrier; control external environment of neurons
Anaxonic neuron
in CNS; many dendrites but no axon
Schwann cells or neurolemmocytes - PNS
make myelin sheath
The glial cells that destroy microorganisms in the CNS are:
microglia
The dendrites of the purkinje cells of the cerebellum are located in the:
molecular layer
myelin sheath
multilayered lipid and protein that covers the axon of some neurons and helps speed neural impulses
somatic nervous system
the division of the peripheral nervous system that controls the body's skeletal muscles
Autonomic sensory neurons
the main input to the ANS comes from
Synapse
the site of communication between 2 neurons
Axons without a myelin sheath are
unmyelinated
neuron
-a nerve cell; the basic building block of the nervous system -lost the ability to undergo mitotic division
Neuroglia
-cells that support and protect neurons -continue to divide throughout and individuals lifetime
Exteroceptors
-external -Receptors in the skin for touch, pressure, pain, and temperature
electrical synapses (gap junctions)
-formed by proteins called connexons present in both cells - provide a direct connection between cells allowing electrical signals to pass between them -faster than chemical synapses -very reliable -limited flexibility
Proprioceptors
-internal -Sensory receptors, located in the muscles and joints, that provide information about body position and movement
Interoceptors
-internal -monitor visceral organs and deep pressure & pain
parallel after-discharge circuit
-signal stimulates neurons arranged in parallel arrays that eventually converge on a single output cell -impulses reach output cell at different times, causing a burst of impulses called an after-discharge
Neurotransmisison at chemical synapse
1. Increased inflow of Ca2+ into the cytosol triggers exocytosis of synaptic vesicles carrying neurotransmitter chemicals. 2. Released into the synaptic let, neurotransmitters diffuse across the cleft and bind to receptors often ligand-gated ion channels. 3. Gated channels open allowing ions to flow according to their concentration gradient. 4. Na flows into the cell making its interior slightly more positive. 5. Potassium flows out of the cell making its interior slightly less positive. 6. The ionic flow through the channels will cause either a graded depolarization or hyperpolarization of the postsynaptic cell membrane. Large graded depolarizations tend to generate action potentials.
2 parts to autonomic motor part
1. Sympathetic 2. Parasympathetic
"brain of the gut"
Enteric Nervous System (ENS)
Lambert-Eaton myasthenic syndrome is an autoimmune disease that attacks voltage-gated calcium channels in the nerve terminal. Calcium channels are unable to open and as a result neurotransmitter is not released. What is a likely symptom of this condition?
Inability to contract the muscles
enteric nervous system
The nervous system of the gastrointestinal tract. It controls secretion and motility within the GI tract, and is linked to the central nervous system.
temporal summation
The sum of one synapse, but multiple times in succession
simple series circuit
a presynaptic neuron stimulates a single postsynaptic neuron
multipolar neuron
in CNS; a neuron with one axon and many dendrites attached to its soma (cell body)
unipolar neuron
in PNS; a neuron with one axon attached to its soma; the axon divides, with one branch receiving sensory information and the other sending the information into the central nervous system. doesn't paddocking trough cell body like bipolar.
Hyperpolarization
inhibitory
autonomic motor neurons
innervate involuntary targets such as smooth muscle, cardiac muscle, and glands
pyramidal cells
large neurons of primary motor cortex
2 types of nervous tissue cells
neurons and neuroglia
effector
responds to impulse at synapse
somatic motor neurons
responsible for reflexes and voluntary control of skeletal muscles
parasympathetic nervous system
rest and digest
nervous system functions
sensory input, integration, motor output