Nervous System: Neural Communication and Anatomy

What is the action potential in neurons?

An action potential is a massive electrical potential that allows Ca 2+ to flow into the cell, leading to the release of neurochemicals in the synapse.

How can a neuron's membrane potential be raised to threshold?

By temporal summation or a large graded potential.

What types of chemical messengers are released by neurons during an action potential?

Paracrines, neurotransmitters, hormones, and neurohormones.

What is the role of the axon in a neuron?

The axon carries electrical and chemical information away from the cell body towards a partner neuron.

What are dendrites and their function in neurons?

Dendrites are branch-like appendages that increase the surface area of the neuron and accept both chemical and electrical signals.

Where is the action potential first generated in a neuron?

At the axon hillock, where the soma and axon meet.

What does it mean that neurons are post-mitotic?

It means that neurons do not divide.

What are glial cells and their function in the nervous system?

Glial cells are support cells that include myelinating cells like oligodendrocytes in the CNS and Schwann cells in the PNS, as well as supporters like microglia and astrocytes.

What is the function of myelinating glial cells?

They provide fatty insulation around neurons, which makes the signal travel faster.

What are sensory receptors and their role in the nervous system?

Sensory receptors are specialized peripheral endings of afferent neurons that respond to specific stimuli and translate them into electrical signals.

What is signal transduction?

The process by which sensory receptors translate the energy form of a stimulus into electrical signals.

What are photoreceptors?

Sensory receptors that respond to visible wavelengths of light.

What do mechanoreceptors respond to?

They are sensitive to mechanical energy.

What is the function of thermoreceptors?

They are sensitive to heat and cold.

What do osmoreceptors detect?

Changes in solute concentrations in body fluids and resultant changes in osmotic activity.

What are chemoreceptors sensitive to?

Specific chemicals, including those for smell and taste, O2 and CO2 in blood, and the chemical content of the digestive tract.

What are nociceptors?

Pain receptors that are sensitive to tissue damage or distortion of tissue.

What are the two divisions of the peripheral nervous system (PNS)?

The autonomic nervous system (ANS) and the somatic nervous system.

What is the role of the sympathetic system in the ANS?

It dominates in emergency or stressful situations, promoting responses that prepare the body for strenuous physical activity.

What does the parasympathetic system do in the ANS?

It dominates in relaxed situations, promoting body-maintenance activities such as digestion.

What is the somatic nervous system?

The division of the PNS that is subject to voluntary control.