Nerves Terms

Dura mater

Outermost and thickest meninx

Satellite cells

PNS -These cells surround nerve cell bodies and dendrites in the PNS, and serve as a buffer.

Schwann cells

PNS -a cell of the peripheral nervous system that wraps around a nerve fiber, jelly-roll fashion, forming the myelin sheath.

Cerebellum

Posterior part of the brain that controls and monitors ongoing movement

What triggers exocytosis of synaptic vesicles

The influx of calcium ions into the axon terminal

Cell Body

The part of a neuron containing the nucleus but not incorporating the axon and dendrites. Also called soma. well-developed gogli apparatus -rough ER called Nissl bodies

which part of the neuron is capable of generating an action potential

Axon

where are synaptic vesicles located

Axon terminals

Hypothalamus

Inferior part of the diencephalon that controls many aspects of homeostasis

Node of Ranvier

a gap in the myelin sheath of a nerve, between adjacent Schwann cells. sites where axon collaterals can emerge

Synapse

a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter. a junction that mediates information transfer from one neuron to another neuron or to an effector cell

Presynaptic neuron

a neuron from the axon terminal of which an electrical impulse is transmitted across a synaptic cleft to the cell body or one or more dendrites of a postsynaptic neuron by the release of a chemical neurotransmitter. conducts impulses toward the synapse

Postsynaptic neuron

a neuron to the cell body or dendrite of which an electrical impulse is transmitted across a synaptic cleft by the release of a chemical neurotransmitter from the axon terminal of a presynaptic neuron. transmits impulse away from the synapse

Depolarization

a positive-going change in a cell's membrane potential, making it more positive, or less negative, and thereby removing the polarity that arises from the accumulation of negative charges on the inner membrane and positive charges on the outer membrane of the cell.

Local potential

a response which affects the neuron internally but may not lead to the conduction of the overall stimulation due to not meeting the threshold level. incoming. Na ions produce current by diffusing short dist.

Dendrite

a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body. Receptive (input) region convey electrical signals toward the cell body as graded potentials

Synaptic vesicle

a small secretory vesicle that contains a neurotransmitter, is found inside an axon near the presynaptic membrane, and releases its contents into the synaptic cleft after fusing with the membrane.

Neurotransmitters that bind the postsynaptic membrane generally generate a/an

action potential

anterior horn

contains the cell bodies of motor neuron

posterior horn

contains the cell bodies of neurons that receive info from sensory neurons

Neuron

excitable cells that transmit electrical signals long lived amitotic function -highly irritable, respond to adequate stimulus by generating an action potential (nerve impulse) impulse is always the same regardless of stimulus

What is the function of the myelin sheath

of a neuron consists of fat-containing cells that insulate the axon from electrical activity. This insulation acts to increase the rate of transmission of signals. A gap exists between each myelin sheath cell along the axon.

Principles of electricity

opposite charges attract each other energy is required to separate opposite charges across a membrane energy is liberated when the charges move toward one another If opposite charges are separated the system has potential energy

Repolarization

refers to the change in membrane potential that returns it to a negative value just after the depolarization phase of an action potential has changed the membrane potential to a positive value.

epidural space

space found around the spinal cord but not in the brain

Action Potential

the change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.

Axon

the long threadlike part of a nerve cell along which impulses are conducted from the cell body to other cells. secretory region of the neuron -releases neurotransmitters to excite or inhibit other cells -function is conducting region of a neuron generates and transmits nerve impulses (action potentials) away from the cell body.

Axon terminal

the somewhat enlarged, often club-shaped endings by which axons make synaptic contacts with other nerve cells or with effector cells (muscle or gland cells). Axon terminals contain neurotransmitters of various kinds, sometimes more than one.

Synaptic cleft

the space between neurons at a nerve synapse across which a nerve impulse is transmitted by a neurotransmitter—called also synaptic gap.

Astrocytes

CNS -The largest and most numerous neuroglial cells in the brain and spinal cord. Astrocytes (from star cells) are irregularly shaped with many long processes, including those with end feet which form the glial (limiting) membrane and directly and indirectly contribute to the blood-brain barrier. They regulate the extracellular ionic and chemical environment, and reactive astrocytes (along with microglia) respond to injury. Astrocytes have high- affinity transmitter uptake systems, voltage-dependent and transmitter-gated ion channels, and can release transmitter, but their role in signaling (as in many other functions) is not well understood.

Oligodendrocytes

CNS -a glial cell similar to an astrocyte but with fewer protuberances, concerned with the production of myelin in the central nervous system.

Ependymal cells

CNS -a type of glial cell. These cells line the CSF-filled ventricles in the brain and the central canal of the spinal cord. The cells are ciliated simple cuboidal epithelium-like cells.

Microglial cells

CNS -small nonneural cells forming part of the supporting structure of the central nervous system. They are migratory and act as phagocytes to waste products of nerve tissue.microg´lial

Epithalamus

Contains the pineal gland and secretes the hormone melatonin

Pia mater

Innermost and thinnest meninx

Arachnoid mater

Middle meninx

Pons

Middle part of the brainstem that bulges anteriorly

Medulla oblongata

Most inferior portion of the brainstem

Midbrain

Most superior part of the brainstem

Hyperpolarization

is a change in a cell's membrane potential that makes it more negative. It is the opposite of a depolarization. It inhibits action potentials by increasing the stimulus required to move the membrane potential to the action potential threshold.

Ganglion

is a nerve cell cluster or a group of nerve cell bodies located in the peripheral nervous system. Cells found in a ganglion are called ganglion cells

Myelin Sheath

is an electrical insulator and allows faster and more energetically efficient conduction of impulses. The sheath is formed by the cell membranes of glial cells (Schwann cells in the peripheral and oligodendroglia in the central nervous system). increase speed of nerve impulse transmission

Thalamus

largest, egg-shaped component of the diencephalon: edits and sorts info coming into to the cerebrum