Nervous System Flashcards

Flashcards covering the topics in Nervous System Pt. 1 and Pt. 2.

What are the two main anatomical subdivisions of the nervous system?

Central Nervous System (CNS) and Peripheral Nervous System (PNS)

What does the Central Nervous System (CNS) consist of?

Brain and spinal cord

Where does the Peripheral Nervous System (PNS) carry signals to and from?

To and from the CNS (Central Nervous System)

Name the two divisions of the PNS.

Sensory and Motor Divisions

What is the function of the sensory division of the PNS?

Carries signals from receptors to the CNS, providing information about environmental changes.

What is the function of the motor division of the PNS?

Carries signals from the CNS to structures, such as muscles or glands, to carry out responses.

What are effectors?

Cells and organs that respond to signals from the motor division, ultimately carrying out response to stimuli.

What are the two subdivisions of the motor division?

Somatic motor division and Autonomic Nervous System (ANS)

What is the function of the somatic motor division?

Carries signals to skeletal muscles, producing voluntary movements.

What is the function of the Autonomic Nervous System (ANS)?

Carries signals to cardiac muscle, smooth muscle, and glands, producing involuntary responses.

Name the two subdivisions of the Autonomic Nervous System (ANS).

Sympathetic division and Parasympathetic division

What is the function of the sympathetic division of the ANS?

Prepares the body for action ('fight or flight').

What is the function of the parasympathetic division of the ANS?

Involved in calming the body ('rest and digest').

What is the main function of neurons?

Communication

What is the neurosoma (soma or cell body)?

Contains the nucleus and is the control center of the neuron.

What is the difference between dendrites and axons in neurons?

Dendrites are the 'receiving end', receiving input from neighboring neurons, while the axon is the 'sending end', the output pathway for signals.

What is the junction between the axon terminal and the cell it’s sending a signal to?

Synapse

Name the three structural classes of neurons.

Multipolar, Bipolar, and Unipolar

Name the three functional classes of neurons.

Sensory (afferent) neurons, Interneurons, and Motor (efferent) neurons

What are the characteristics of Multipolar neurons?

One axon and multiple dendrites

Where are Bipolar neurons found?

Associated with sense organs like neurons in the nose for olfaction, neurons in the retina for vision and sensory neurons of the ear.

What is the main function of Sensory (afferent) neurons?

Specialized in detecting stimuli and sending information to the CNS.

What is the main function of Interneurons?

Perform integrative functions, processing, storing, and retrieving information and making decisions about how the body should respond.

What is the main function of Motor (efferent) neurons?

Specialized to carry outgoing signals from the CNS to the cells and organs that carry out commands.

What are the 4 kinds of glial cells in the CNS?

Oligodendrocytes, Ependymal cells, Microglia, and Astrocytes

What are the 2 kinds of glial cells in the PNS?

Satellite cells and Schwann cells

What is the function of Oligodendrocytes?

Surround nearby axons and form a layer of insulation called the myelin sheath

What is the function of Ependymal cells?

Line the internal fluid-filled cavities of the brain and spinal cord and produce cerebrospinal fluid (CSF)

What is the function of Microglia?

Small phagocytic cells that wander the CNS and destroy pathogens, debris, or foreign matter.

What is the function of Astrocytes?

Form structural framework of nervous tissue, support energetic demands of neurons, secrete growth factors, maintain extracellular environment, convert glucose to lactate, and form scar tissue in damaged regions.

What is the function of Satellite cells?

Surround cell bodies of peripheral neurons, insulating them electrically and regulating their chemical environment

What is the function of Schwann cells?

Wrap around axons of peripheral neurons, forming a sleeve called the neurilemma, depositing multiple layers of its membrane to form the myelin sheath, and playing a role in repairing damaged axons.

What is the role of the myelin sheath in signal conduction?

Insulates the axon, ensuring rapid, efficient signal conduction.

What are the gaps between segments of the myelin sheath called?

Nodes of Ranvier

What is the difference between myelinated and unmyelinated axons?

Myelinated axons conduct signals much faster than unmyelinated axons.

What are the two forms of nervous tissue?

White matter and Gray matter

What is white matter?

Formed by bundles of myelinated nerve axons called tracts and carries signals from place to place.

What is gray matter?

Where neurosomas, dendrites, and synapses are located, and is the information processing part of the CNS.

What creates electrical signals of nerves?

Movement of Na+ and K+

What is the resting membrane potential (RMP)?

Charge difference in unstimulated neuron.

What maintains the RMP?

Sodium-potassium pump maintains RMP.

What is the function of the Sodium-potassium pump?

Pumps 3 Na+ out and Pumps 2 K+ in

What is the function of Ligand-gated channels?

Opens or closes in response to a ligand binding to it

What is the function of Voltage-gated channels?

Opens and closes in response to changes in membrane potential

What happens when Na+ flows into the neuron during local potential?

Makes the inside of the neuron less negative

What is Depolarization?

Na+ raises voltage closer to 0mV

What happens when the local potential reaches the axon hillock?

If the local potential reaches the minimum voltage called threshold, voltage-gated channels open and an action potential is produced

What happens during Depolarization in Action Potential?

Na+ rushes into the neuron and causes a rapid rise in voltage, closing around 0mV and rising to about +35mV.

What happens during Repolarization in Action Potential?

Voltage-gated K+ channels open, K+ flows out of neuron, the inside of neuron becomes negative again.

What is the refractory period?

After action potential occurs, that area of the membrane cannot be stimulated for a short time

What is continuous conduction?

An action potential occurs at every point along the axon in unmyelinated neurons.

What is saltatory conduction?

The signal appears as if the signal is jumping from node to node in myelinated neurons.

What do Synaptic vesicles contain?

Chemicals called neurotransmitters

What triggers synaptic vesicles to undergo exocytosis?

Arrival of nerve signal

What gets broken down by enzymes or reabsorbed by presynaptic neuron?

Neurotransmitters