Chapter 11: Nervous Tissue

neurons are classified functionally as sensory, interneurons, or motor neurons.

Classify neurons based on their function

the central nervous system consists of the brain and spinal cord and it integrates, processes, and coordinates sensory data and motor commands. The peripheral nervous system consists of all the nervous tissue outside the central and enteric nervous systems.

Compare the central and peripheral nervous system

Membrane potential is the unequal charge distribution between the inner and outer surfaces of the plasma membrane

Define membrane potential

high concentrations of potassium ions and negatively charged proteins

In a typical undisturbed cell, the extracellular fluid (ECF) contains high concentrations of sodium ions and chloride ions, whereas the cytosol contains __________.

forming a cellular cord that directs axonal regrowth

In the peripheral nervous system, Schwann cells participate in the repair of damaged nerves by

resting membrane potential (RMP)

Ions are unequally distributed across the plasma membrane of all cells. This ion distribution creates an electrical potential difference across the membrane. What is the name given to this potential difference?

the inside surface of the plasma membrane is much more negatively charged than the outside surface

On average, the resting membrane potential is -70 mV. What does the sign and magnitude of this value tell you?

multipolar

The most abundant class of neuron in the central nervous system is

there are many more K+ leak channels than Na+ leak channels in the plasma membrane.

The plasma membrane is much more permeable to K+ than to Na+. Why? -There are many more voltage-gated K+ channels than voltage-gated Na+ channels. -Ligand-gated cation channels favor a greater influx of Na+ than K+. -The Na+-K+ pumps transport more K+ into cells than Na+ out of cells. -There are many more K+ leak channels than Na+ leak channels in the plasma membrane

the presence of concentration gradients and leak channels

The resting membrane potential depends on two factors that influence the magnitude and direction of Na+ and K+ diffusion across the plasma membrane. Identify these two factors

potential

The separation of plus and negative charges across the membrane creates a ________ difference, or voltage. -concentration -potential -graded -kinetic -gradient

conducting action potentials

Functions of astrocytes include all of the following except -absorbing excess neurotransmitter -responding to neural tissue damage -maintaining the blood-brain barrier -forming a three-dimensional framework for the CNS -conducting action potentials

leak channels

Sodium and potassium ions can diffuse across the plasma membranes of all cells because of the presence of what type of channel?

autonomic

The ________ nervous system provides involuntary regulation of smooth muscle, cardiac muscle, and glandular activity.

Na+-K+ ATPase

What prevents the Na+ and K+ gradients from dissipating?

astrocytes

Which glial cell protects the CNS from chemicals and hormones circulating in the blood?

satellite cells

Which of the following is a type of glial cell found in the peripheral nervous system? -astrocytes -oligodendrocytes -ependymal cells -satellite cells -microglia

axon and telodendria

Which part(s) of the neuron can conduct an action potential? -dendrites -dendrites and cell body -cell body and axon -axon and telodendria -dendrites and telodendria

they lack centrioles.

Why are CNS neurons that are lost to injury or disease seldom replaced?

proprioceptors

________ monitor the position of skeletal muscles and joints.