Nervous Tissue Part I

Vocabulary flashcards covering key terms and definitions from the 'Nervous Tissue Part I' lecture regarding the organization and cell types of the nervous system.

Central Nervous System (CNS)

Comprised of the Brain & Spinal Cord.

Peripheral Nervous System (PNS)

Has two distinct parts: Somatic Nervous System (SNS) and Autonomic Nervous System (ANS).

Somatic Nervous System (SNS)

Conveys sensory information from skin, muscles, joints to the CNS, or motor information from CNS to skeletal muscle.

Autonomic Nervous System (ANS)

Involuntarily conveys information to smooth muscle, cardiac muscle, and glands.

Afferent Nerves

Nerves that convey sensory information towards the central nervous system.

Efferent Nerves

Nerves that convey motor information away from the central nervous system.

Parasympathetic Nervous System

A division of the autonomic nervous system.

Sympathetic Nervous System

A division of the autonomic nervous system.

Nervous Tissue

The tissue that comprises the nervous system, containing neurons and glial cells.

Neuron

A major cell type in nervous tissue that is larger and propagates an action potential.

Glial (Neuroglia) Cells

The majority cells in nervous tissue; they do not propagate an action potential.

Action Potential (Nerve Impulse)

The rapid alteration of a cell membrane's ionic gradient that propagates along the cell membrane.

Cell Body (Soma)

A major component of a neuron, containing the nucleus and other organelles.

Processes (Neurites)

Extensions of a neuron, including dendrites and axons.

Perikaryon

Another term for the cell body of a neuron.

Nissl Bodies

Rough endoplasmic reticulum (rER) found in the perikaryon, responsible for protein synthesis.

Dendrites

Main signal reception and processing sites of a neuron that increase receptor surface area and have dendritic spines.

Axon

A process of a neuron that conducts action potentials away from the cell body.

Myelin Sheath

An insulating layer around an axon that helps to speed up nerve impulses.

Axon Terminals

The endings of an axon that form axodendritic, axosomatic, or axoaxonic synapses.

Schwann Cell (Neurolemmocyte)

A glial cell responsible for forming the myelin sheath in the peripheral nervous system.

Node of Ranvier

Gaps or interruptions in the myelin sheath along an axon.

Axon Hillock

The region of the cell body where the axon originates, and where excitatory and inhibitory stimuli are summed.

Initial Segment

The part of the axon just past the axon hillock where excitatory and inhibitory stimuli are summed.

Endoneurium

Connective tissue that surrounds individual nerve fibers.

Neuropil

The fibrous intercellular network surrounding cells of the CNS, consisting of processes of neurons and glial cells.

Dendritic Spines

Small projections on dendrites that increase the receptor surface area for synaptic connections.

Axolemma

The plasma membrane that encloses the axon.

Axoplasma

The cytoplasm found within the axon.

Terminal Arborization

The extensive branching at the end of an axon, forming multiple synaptic boutons.

Boutons

Swollen regions at the ends of axon terminals where neurotransmitters are released.

Anterograde Transport

The transport of cytoplasmic components away from the soma (cell body) towards the axon terminal.

Retrograde Transport

The transport of cytoplasmic components from the axon terminal back towards the soma (cell body).

Sensory Neurons (Afferent)

Neurons that conduct sensory information, leading into the CNS.

Motor Neurons (Efferent)

Neurons that conduct motor information, leading out of the CNS to muscles or glands.

Interneuron

A neuron that acts as a connector between other neurons, typically found within the CNS.

Multipolar Neuron

A neuron characterized by one axon and multiple dendrites.

Bipolar Neuron

A neuron characterized by one axon and one dendrite, typically extending from opposite ends of the cell body.

Pseudounipolar Neuron

A neuron with a single process that divides into a peripheral process and a central process.

Peripheral Process

A part of a pseudounipolar neuron's process that extends towards sensory receptors in the body.

Central Process

A part of a pseudounipolar neuron's process that extends into the CNS.

Synapse

A junction between two neurons (or between a neuron and an effector) where information is transmitted.

Axodendritic Synapse

A type of synapse formed between an axon and a dendrite.

Axosomatic Synapse

A type of synapse formed between an axon and the cell body (soma) of another neuron.

Axoaxonic Synapse

A type of synapse formed between two axons.

Presynaptic Terminal

The part of the neuron that releases neurotransmitters into the synaptic cleft.

Synaptic Cleft

The small space between the presynaptic and postsynaptic terminals through which neurotransmitters diffuse.

Postsynaptic Terminal

The part of the neuron (or effector cell) that receives neurotransmitters and has receptors.

Neurotransmitter

Chemical messengers released from presynaptic vesicles that diffuse across the synaptic cleft to bind to postsynaptic receptors.

Excitation/Depolarization

A process where neurotransmitter binding alters cell membrane permeability, making the membrane potential more positive and increasing the likelihood of an action potential.

Inhibition/Hyperpolarization

A process where neurotransmitter binding alters cell membrane permeability, making the membrane potential more negative and decreasing the likelihood of an action potential.