Lect 6 - Neurons Flashcards by Kevin Tea

What is the CNS associated with? What does it do?

Brain and Spinal Cord

Control Center
Respond to Stimuli
Interpret Sensory Info

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What is the PNS associated with?

Tissue outside the CNS

Afferent and Efferent that links CNS with organs and other systems

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PNS can be divided into? What does each division do?

Afferent Division:
Brings sensory info to CNS
Starts at receptors

Efferent Division
Carries motor commands to muscles/glands
Ends at effectors

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Neural Cortex

Layer of gray matter on surface of the brain

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Center (CNS Gross Anatomy)

Group of neurons in the CNS that share a common function

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Nucleus (CNS Gross Anatomy)

A center in the CNS with its own anatomical boundaries

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Tract (CNS Gross Anatomy)

Bundle of axons within the CNS

They all share the same origin, destination, and function

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Column (CNS Gross Anatomy)

Group of tracts found within a specific region of the spinal cord

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Ganglion (CNS Gross Anatomy)

Sensor/Motor neuron within the PNS

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Afferent can be subdivided into

Somatic: Skeletal Muscles

Visceral: Internal Organs

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Efferent can be subdivided into

Somatic Nervous System (SNS)

Autonomic Nervous System (ANS)

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Autonomic Nervous System can be subdivided into. What is it responsible for?

Parasympathetic Division
Sympathetic Division

Controls Visceral Functions (Gut, glands, internal organs)

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What are the different types of neurons

Sensory Neuron
Carries sensory info from PNS to CNS
Motor Neuron
Carries motor commands from CNS to effectors

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What are Neuroglia

Supports neurons
Regulate environment
Defend from pathogens
Repair nervous tissue

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What are Dendrites

Respond to specific stimuli in the extracellular environment or activity of other cells

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What are Neurons

Nerve Cells that transfer and process info within the nervous system

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What is the Cell Body (Neurons)

Main part of the neuron, contains nucleus, mitochondria, ribosomes, and other organelles

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What is the Axon

Conducts nerve impulses towards the axon terminals

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What are Axon Terminals

Affect other neurons or effector organs (Muscle/Organ)

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Define Excitability (Action Potenital)

Ability of a plasma membrane to respond to an adequate stimulus and generate an action response.

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What makes a cell have membrane potential

Cell has an uneven distribution of ions resulting in a potential difference

Do all cells have membrane potential?

Yes all cells do have some sort of membrane potential, changing this membrane potential dramatically can excite cells

Define Membrane Potential

The uneven distribution of positive/negative ions across the plasma membrane

Define Threshold Stimulus

Level of stimuli needed to cause a change in membrane permeability

What affects the speed of an action potential

Size of the Myelinated Axon Larger Axons are faster If the axon is Myelinated Myelination allows for faster impulses

How do ion channels show selectivity

Diameter of pore Distribution of charged/non-polar amino acids throughout the pore

What are the different methods of gating for an Ion Channel

Conformation Change (In One Region) Channel closes in the centre General Structural Change Entire channel changes Blocking Particle Little particle plugs channel

What are the different methods of opening/closing an ion channel

Ligand-Gated Phosphorylation-Gated Voltage-Gated Mechanically-Gated

What is Ligand-Gated

Binding of ligand causes conformational change

What is Phosphorylation-Gated

G-protein or other signal transduction causes conformational change

What is Voltage-Gated

Changes in distribution of charges across the membrane causes conformational change

What is Mechanically-Gated

Cytoskeleton causes conformational change

What kind of things are Ligand-Gated (Neurons)

Dendrites Soma (Cell Body)

What kind of things are Phosphorylation-Gated (Neurons)

Dendrites Soma (Cell Body)

What kind of things are Voltage-Gated (Neurons)

Axon Hillock Axon Terminal

What kind of things are Mechanically-Gated (Neurons)

Receptors ends of Sensory Afferents

In a neuron where are passive ion channels located

Throughout the neuron

What does the CNS Neuroglia contain

Astrocytes Oligodendrocytes Microglia Ependymal Cells

What are Astrocytes? What are their function?

The largest and most numerous Neuroglia Make up the blood brain barrier Prevents drugs from entering the brain and isolate CNS from general circulation

What are Oligodendrocytes

Neuroglia of the CNS Forms myelin sheath Forms internodes Form myelin sheath gaps

What is White Matter

Areas with mostly myelinated axons

What is Gray Matter

Areas with mostly devoid of myelinated axons Dendrites and Cell bodies are made up of gray matter

What are Microglia

Neuroglia of the CNS Phagocytic Cells Gets rid of invaders in CNS, also gets rid of debris

What are Ependymal Cells

Neuroglia of the CNS Involved in the production of cerebrospinal fluid (CSF) Makes up a cellular lining called the ependyma

Ganglia (PNS)

Clusters of cell bodies in the PNS

Peripheral Nerves (PNS)

Axons that are bundled together

What are the two types of Neuroglia (PNS)

Satellite Cells Schwann Cells (Neurolemmocytes)

What are Satellite Cells? What are their function?

Neuroglia of the PNS Surrounds Cell Bodies, mimics astrocytes regulating external chemical environment

What are Schwann Cells

Neuroglia of the PNS Surround axons, mimics oligodendrocytes covering neurons in a myelin sheath

What are Schwann Cells composed of

Axolemma/Neurolemma