CH2: Cells and Structures Flashcards
What are the four zones of the neuron and their corresponding structures?
1) Input zone: dendrite first; where neurons collect and integrate information, either from the environment or from other cells
2) integration zone: cell body (soma); where the decision to produce a neural signal is mad
3) conduction zone: axon (nerve fiber); where information can be transmitted over great distance
4) output zone: axon terminals; where the neuron transfers information to other cells
Dendrite
An extension of the cell body that receives information from other neurons
Cell body
Also called soma. The region of a neuron that is defined by the presence of the cell nucleus
Axon
Also called nerve fiver. A single extension from the nerve cell that carries action potentials from the cell body toward the axon terminal
Axon terminal
Also called synaptic bouton. The end of of an axon or axon collateral, which forms a synapse with a neuron or other target cell
Motoneuron
Also called motor neuron. A neuron that transmits neural messages to muscles (or glands)
Sensory neurons
A nerve cell that is directly affected by changes int he environment, such as light, odor, or touch
Interneuron
A nerve cell that is neither a sensory neuron or a motoneuron; interneurons receive input from and send output to other neurons
What are the 3 general shapes of neurons?
Multipolar neurons, bipolar neurons, and unipolar neurons
Multipolar neuron
A nerve cell that has many dendrites and a single axon. They are the most common type of neuron
Bipolar neuron
A nerve cell that has a single dendrite at one end and a single axon at the other end. They are common in sensory systems, such as vision
Unipolar neuron
A nerve cell with a single branch that leaves the cell body and then extends in two directions; one end is the input zone, and the other end is the output zone. Unipolar neurons transmit touch information from the body into the spinal cord
What are 3 components of the synapses
Presynaptic membrane, postsynaptic membrane, and a synaptic cleft
Presynaptic membrane
The specialized membrane on the axon terminal of a nerve cell that transmits information by releasing neurotransmitter
Postsynaptic membrane
The specialized membrane on the surface of a neuron that receives information by responding to neurotransmitter from a presynaptic neuron
Synaptic cleft
The space between the presynaptic and postsynaptic neurons at a synapse.
Synaptic vesicle
A small, spherical structure that contains molecules of neurotransmitter
Neurotransmitter
The chemical released from the presynaptic axon terminal that serves as the basis of communication between neurons
Neurotransmitter receptor (or just receptor)
A specialized protein, often embedded in the cell membrane, that selectively senses and reacts to molecules of a corresponding neurotransmitter or hormone
Neuroplasticity
The ability of the nervous system to change in response to experience or the environment
Axon hillock
The cone-shaped area on the cell body from which the axon originates
Innervate
To provide neural input to; electrical signals race down the axon toward the targets
Axon collateral
A branch of an axon
Axonal transport
The transportation of materials from the neuronal cell body toward the axon terminals, and from the axon terminals back toward the cell body
Glial cells
Nonneuronal brain cells that provide structural, nutritional, and other types of support to the brain
What are the four types of glia cells
Oligodendrocyte, Schwann cells, astrocyte, and microglial cells
Oligodendrocytes
A type of glial cell that forms myelin in the peripheral nervous system
Schwann cell
A type of glial cell that forms myelin in the peripheral nervous system
Myelin
A fatty insulation around an axon, formed by glial cells. This sheath boosts the speed at which nerve impulses are conducted
Node of Ranvier
A gap between successive segments of the myelin sheath where the axon membrane is exposed
Astrocyte
A star-shaped glial cell with numerous processes (extensions) that run in all directions
Microglial cells
Extremely small motile glial cells that remove cellular debris from injured or dead cells
What can of problems can glial cells cause?
Glial cells can dived in adulthood which can rise to deadly tumors. Some glial cells, astrocytes, respond to brain injury by changing size-swelling. It damages neurons and is responsible for many symptoms of brain injuries
Edema
The swelling of tissue in response to injury
Gross neuroanatomy
Anatomical features of the nervous system that are visible to the naked eye
Central nervous system (CNS)
The portion of the nervous system that includes the brain and the spinal cord.c
Peripheral nervous system (PNS)
The portion of the nervous system that includes all the nerves and neurons inside the brain and the spinal cord.
Nerve
A collection of axons bundled together outside of the CNS