Module 2: Nervous system function

List the types of glial cells and their functions.

Astrocytes: Regulate ionic and nutritional composition of the cerebrospinal fluid bathing the brain, stimulate the capillaries of the brain to form the blood-brain barrier by forming tight junctions between the capillary epithelial cells, provide nutrients and remove wastes for neurons, guide growing neurons to proper destination, participate in information signaling.

Dendritic spines

Increase surface are of dendrites.

Which classes of neurons are most likely to repair themselves after damage?

Peripheral neurons (afferent and efferent) are more likely to repair themselves than interneurons in the central nervous system.

Central nervous system

Brain and spinal cord

Glial cells

Non-neural cells that are very important in supportive functions of neurons.

Collaterals

branches of an axon

Myelin

A layer of modified plasma membrane wrapped around the axon by a nearby supporting cell.

Postsynaptic neuron

A neuron conducting signals away from a synapse.

Presynaptic neuron

A neuron conducting signals away from a synapse.

Varicosities

Bulging areas along the axon where some neurons release their chemical messengers

Neurotransmitters

Chemical messengers used to communicate with other cells.

Interneurons

Connect neurons within the CNS. Function as integrators and signal changers/ Integrate groups of afferent and efferent neurons into reflex circuits. Lie entirely within the CNS. Account for > 99% of all neurons.

Efferent neurons

Convey information away from the CNS to effector cells like muscle, gland, or other cell types. Cell body with multiple dendrites and a small segment of the axon are in the CNS; most of the axon is in the PNS.

Afferent neurons

Convey information from the tissues and organs of the body towards the CNS. Single process from the cell body splits into a long peripheral process (axon) that is in the PNS and a short central process (axon) that enters the CNS.

Write out the functions of neuronal dendrites, cell body, axon hillock, axon, axon terminal, myelin sheath, dynein, and kinesin.

Dendrite: Branches of neurons that receive information and transmit toward the cell body. Cell body: Central region of neuron containing the nucleus. Axon hillock: Initial region of axon, where action potentials are often initiated. Axon: Branch of neuron carrying information away from the cell body. Myelin sheath: Layers of plasma membrane wrapping around axon, produced by glial cells, which speed up information transmission. Dynein: Motor protein that moves materials along the cytoskeleton of the axon toward the cell body. Kinesin: Motor protein that moves materials along the cytoskeleton of the axon away from the cell body.

Astrocyte

Helps regulate the composition of the extracellular fluid in the CNS by removing potassium ions and neurotransmitters around the synapses. Also stimulates the formation of right junctions between the cells that make up the walls of capillaries found in the CNS. Information signaling in the brain.

Dendrites

Highly branched outgrowths of the cell that receive incoming information from other neurons. The structure of these increases a cell's capacity to receive signals from other neurons.

Anterograde

Kinesin transport mainly occurs from the cell body toward the axon terminals.

Ependymal cells

Line the fluid-filled cavities within the brain and spinal cord and regulate the production and flow of cerebrospinal fluid.

Retrograde

Movement of dynein in the opposite direction. Carrying recycled membrane vesicles, growth factors, and other chemical signals that can affect the neuron's morphology, biochemistry, and connectivity.

Peripheral nervous system

Nerves that connect the brain and spinal cord with the body's muscles, glands, sense organs, and other tissues.

Neurons

Operate by generating electrical signals that move from one part of the cell to another part of the same cell or to neighboring cells. Serve as integrators because heir output reflects the balance of inputs they receive from up to hundreds of thousands of other neurons.

Axon hillock (initial segment)

Propagated electrical signals are generated here. These signals propagate away from the cell body along the axon.

Sensory receptors

Respond to various physical or chemical changes in their environment by generating electrical signals in the neuron.

Axon terminal

Responsible for releasing neurotransmitters from the axon. These messengers diffuse across an extracellular gap to the cell oppose the terminal.

Blood-brain barrier

Selective filter for exchanging substances

Kinesins and Dyneins

Specialized types of motor proteins. At one end, they bind to their cellular cargo, and at the other end use ATP to "walk" along the microtubules.

Schwann cells

Supporting cells of the peripheral nervous system responsible for the formation of myelin.

Glial cells

Surround the axon and dendrites of neurons, physical and metabolic support. Retain the capacity to divide throughout life.

Synapse

The anatomically specialized junction between two neurons where one neuron alters the electrical and chemical activity of another.

Nodes of Ranvier

The spaces between adjacent sections of myelin where the axon's plasma membrane is exposed to extracellular fluid.

Microglia

Type of CNS glial cell that are microphage-like cells that perform immune functions in the CNS, and may also contribute to synapse remodeling and plasticity.

Oligodendrocytes

Type of glial cell in the CNS that wrap axons in a myelin sheath.

Cell body (soma)

contains the nucleus and ribosomes and thus has the genetic information and machinery necessary for protein synthesis.

Axon

long process that extends from the cell body and carries outgoing signals to its target cells.