Ch 11 Review (2)

What is the function of the nervous system?

To coordinate and control body activities by transmitting signals between different body parts.

Which organs are part of the central nervous system?

The brain and spinal cord.

Which structures are part of the peripheral nervous system?

Nerves and ganglia outside the central nervous system.

What is the function of the Autonomic Nervous System?

Regulates involuntary bodily functions, such as heart rate and digestion.

Describe the two parts of the Autonomic Nervous System.

Sympathetic (fight or flight response) and Parasympathetic (rest and digest response).

Which part of the nervous system is voluntary?

The Somatic Nervous System.

What is the function of the Sensory Nervous System?

To carry sensory information from the body to the central nervous system.

What is another name for afferent nerves?

Sensory nerves.

Function of afferent nerves?

They transmit sensory information to the central nervous system.

What is another name for efferent nerves?

Motor nerves.

Function of efferent nerves?

They transmit motor signals from the central nervous system to muscles and glands.

Which organs function in integration of the stimulus?

The brain and spinal cord.

Which CNS cells have cilia and move the cerebral spinal fluid?

Ependymal cells.

When do neurons lose mitotic ability?

Neurons lose mitotic ability during development, typically after birth.

What is a ganglia and nuclei?

Ganglia are clusters of neuron cell bodies in the PNS; nuclei are clusters of neuron cell bodies in the CNS.

Define astrocyte.

A type of glial cell that maintains the blood-brain barrier and regulates nutrient exchange.

Define ependymal cell.

A type of glial cell that lines the ventricles of the brain and produces cerebrospinal fluid.

Define microglial cell.

A type of glial cell that acts as the immune defense in the CNS.

Define oligodendrocyte.

A type of glial cell that forms myelin sheaths around axons in the CNS.

Define satellite cell.

A type of glial cell that surrounds neuron cell bodies in the PNS and regulates their environment.

Define Schwann cell.

A type of glial cell that forms myelin sheaths around axons in the PNS.

What is an association neuron?

A neuron that connects sensory and motor neurons within the CNS.

Which part of a neuron receives messages?

The dendrites.

Which part of the neuron sends messages?

The axon.

At what end of the neuron is a message communicated to a neighboring cell?

At the axon terminals.

What is found in the cell body of a neuron?

Cell organelles, including the nucleus and cytoplasm.

How do dendrites and axons differ?

Dendrites receive signals; axons transmit signals.

What is myelin?

Myelin is a fatty substance that insulates axons to increase the speed of nerve impulse conduction.

What is the function of myelin?

To insulate axons and enhance the speed of nerve impulses.

The velocity of nerve impulse is greatest in myelinated neurons with __________ diameters.

large.

How is myelin different in the CNS and PNS?

In the CNS, myelin is formed by oligodendrocytes; in the PNS, it is formed by Schwann cells.

Where do you find unipolar neurons, bipolar neurons, and multipolar neurons?

Unipolar in sensory neurons; bipolar in some sensory organs; multipolar in motor neurons.

What is the polarized membrane state?

A state where the inside of the cell is more negatively charged than the outside.

How is the polarized membrane state maintained?

By the sodium-potassium pump and selective permeability of the membrane.

Describe Action potential in a sequence of events.

Depolarization, repolarization, and hyperpolarization.

Compare and contrast depolarization and hyperpolarization.

Depolarization makes the membrane less negative; hyperpolarization makes it more negative.

What is repolarization?

The process of restoring the membrane potential to a negative value after depolarization.

What is the membrane potential at rest?

Approximately -70 mV.

Describe the events that must occur to generate an Action Potential.

Na+ influx causing depolarization followed by K+ efflux for repolarization.

What ions increase in permeability during depolarization?

Sodium ions (Na+).

What ions increase in permeability during repolarization?

Potassium ions (K+).

What ions increase in permeability at hyperpolarization?

Chloride ions (Cl-) or further potassium ions (K+).

How soon can a second action potential be generated in a cell?

After the absolute refractory period, which ensures one-way conduction.

Define absolute refractory period.

A period during which a second action potential cannot be initiated, regardless of stimulus strength.

What are neurotransmitters?

Chemical messengers that transmit signals across the synapse from one neuron to another.

What are the different types of neurotransmitters?

Amino acids, peptides, monoamines, and gases.

Which neurotransmitter inhibits pain?

Endorphins.

Which drugs mimic endorphins?

Opioids.

Which neurotransmitter is found in skeletal muscle?

Acetylcholine.

What is the role of acetylcholinesterase?

To break down acetylcholine in the synaptic cleft to terminate the signal.

The ___________cleft prevents an impulse from being transmitted directly from one neuron to another.

synaptic.

Compare graded potential to non-graded.

Graded potentials vary in magnitude and decrease with distance; non-graded potentials are all-or-nothing.

What is inhibitory postsynaptic potential (IPSP)?

A temporary hyperpolarization of a postsynaptic membrane, making it less likely to fire an action potential.

What is excitatory postsynaptic potential (EPSP)?

A temporary depolarization of a postsynaptic membrane, making it more likely to fire an action potential.

Define synaptic delay.

The time it takes for a signal to cross the synaptic cleft.