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