Nervous System Overview

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Questions and Answers

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

Blood and muscles
Brain and spinal cord (correct)
Kidneys and lungs
All nerves and receptors

What does the Peripheral Nervous System (PNS) consist of?

Brain and spinal cord
All nerves and receptors (correct)
Heart and blood vessels
Lungs and kidneys

What are the four major parts of the brain?

Cerebrum, Cerebellum, Brain Stem, and Diencephalon

What are the three functions of the nervous system?

Sensory Function (Afferent), Integrative Function, and Motor Function (Efferent) Signup and view all the answers

What is a Sensory Function (Afferent)?

It carries information from the PNS to the CNS Signup and view all the answers

What is an Integrative Function?

When the brain is processing the information Signup and view all the answers

What is a Motor Function (Efferent)?

It carries the motor commands from the CNS to the PNS Signup and view all the answers

What are the two types of cells in the nervous system?

Neurons and Neuroglia (glial cells) Signup and view all the answers

What are Neurons?

They transmit the nerve impulse and do not replicate nor replace themselves when injured Signup and view all the answers

What are Neuroglia (glial cells)?

They are the most abundant nerve cell that supports and nourishes the neurons Signup and view all the answers

What are the parts of a Neuron?

Dendrites, Cell body, Ganglion (ganglia), Axon, Axon terminals (synaptic knobs), Myelin sheath (myelin), Schwann cells, and Nodes of Ranvier Signup and view all the answers

What are Dendrites?

Branchlike part of the neuron that transmits the nerve impulse toward the cell body Signup and view all the answers

What is the Cell body?

Located in the CNS and contains DNA Signup and view all the answers

What is a Ganglion (ganglia)?

Group of cell bodies in the PNS Signup and view all the answers

What does an Axon do?

Carries impulses away from cell body to the target organ Signup and view all the answers

What are Axon terminals (synaptic knobs)?

Ends of the axon that stores neurotransmitters Signup and view all the answers

What is the Myelin sheath?

White fatty material that insulates the axon and speeds up nerve impulses Signup and view all the answers

What is the difference between Myelinated axon and Unmyelinated axon?

Myelinated axons have myelin and unmyelinated axons do not contain myelin Signup and view all the answers

What is White matter?

Myelinated axons Signup and view all the answers

What is Gray matter?

Unmyelinated axons Signup and view all the answers

What are Interneurons?

Transmit nerve impulses from one neuron to another Signup and view all the answers

What are the four types of cells in the CNS?

Astrocytes, Oligodendrocytes, Ependymal cells, Microglia Signup and view all the answers

What are Astrocytes?

Help maintain our blood brain barrier Signup and view all the answers

What are Oligodendrocytes?

Produces myelin in the CNS, can produce enough myelin for 70 different axons Signup and view all the answers

What are Ependymal cells?

Line the cavities within the brain and contain cilia to keep the cerebral spinal fluid moving Signup and view all the answers

What are Microglia?

Cleans up the debris in the CNS Signup and view all the answers

What are Satellite cells?

Surround neuron cell bodies in the ganglia of the PNS. Help regulate the chemical environment of the neurons. Signup and view all the answers

What are Schwann cells?

Produce myelin in the PNS Signup and view all the answers

What are Nodes of Ranvier?

Gaps between the myelin and is the only place that a nerve impulse can happen Signup and view all the answers

What is the Blood brain barrier?

Made up of tight junctions which prevent toxic substances from entering the blood stream in our brain Signup and view all the answers

What are Nerve impulses?

Electrical signal from a neuron to another structure Signup and view all the answers

What is an Action potential?

Nerve impulse Signup and view all the answers

What is Potassium (K+)?

We have a lot of potassium on the inside of our cells, which can leak out Signup and view all the answers

What is Sodium (Na+)?

A lot of sodium is on the outside of our cells Signup and view all the answers

What is Polarization?

The resting state of a neuron, the inside of the cell is more negative than the outside of the cell Signup and view all the answers

What is Depolarization?

Sodium ions are flooding into the cell Signup and view all the answers

What is Repolarization?

Potassium is leaving the cell but leaves slowly Signup and view all the answers

What is the Refractory period?

An action potential cannot take place because the axon is busy and directs the action potential to continue down the axon Signup and view all the answers

What is the All-or-nothing manner?

Action potential does not lose strength with distance Signup and view all the answers

What is Saltatory conduction?

When the action jumps from one Node of Ranvier to the next Signup and view all the answers

What is meant by Synapses across neurons?

Nerves never touch anything Signup and view all the answers

What is the Synaptic cleft?

The space between the nerve and the next structure Signup and view all the answers

What are Neurotransmitters?

Chemicals that send a message from the nerve to another structure. Acetylcholine (Ach) and Norepinephrine (NE) Signup and view all the answers

What are Receptor sites?

Locations on a receptor neuron into which a specific neurotransmitter fits like a key into a lock Signup and view all the answers

What are the events at the Synapsis?

<ol> <li>The nerve impulse travels along neuron A to its axon terminal. 2. The neurotransmitter is released into the synaptic cleft. 3. Neurotransmitter travels across the synaptic cleft and binds to the receptor sites. 4. The nerve impulse travels toward the cell body and axon of neuron B.</li> </ol> Signup and view all the answers

Study Notes

Central Nervous System (CNS)

Composed of the brain and spinal cord, which serve as the main control center for the body.

Peripheral Nervous System (PNS)

Encompasses all nerves and receptors outside of the CNS, facilitating communication between the CNS and the rest of the body.

Major Parts of the Brain

Four primary regions: Cerebrum, Cerebellum, Brain Stem, Diencephalon.

Functions of the Nervous System

Sensory Function (Afferent): Transmits sensory information from PNS to CNS.
Integrative Function: Involves processing and interpreting sensory input by the brain.
Motor Function (Efferent): Carries motor commands from CNS to PNS to elicit responses.

Types of Nervous System Cells

Neurons: Transmit nerve impulses; do not regenerate after injury.
Neuroglia (Glial Cells): Provide support and nourishment to neurons; more numerous than neurons.

Neuron Structure

Dendrites: Branch-like extensions that receive signals and direct them to the cell body.
Cell Body: Contains the nucleus and DNA; crucial for neuron function.
Ganglion (Ganglia): Clusters of nerve cell bodies in the PNS.
Axon: Conducts impulses away from the cell body toward target structures.
Axon Terminals (Synaptic Knobs): Release neurotransmitters to communicate with other neurons.
Myelin Sheath: Insulating layer that enhances speed of impulse transmission.
Schwann Cells: Form myelin sheath in the PNS.
Nodes of Ranvier: Gaps in the myelin sheath where action potentials occur.

Myelination

Myelinated Axons: Have a myelin cover, enabling faster impulse conduction.
Unmyelinated Axons: Lack myelin, resulting in slower impulse transmission.

Nervous Tissue Types

White Matter: Defined by myelinated axons, involved in the rapid transmission of signals.
Gray Matter: Comprised of unmyelinated axons and cell bodies, involved in processing information.

Interneurons

Responsible for transmitting signals between neurons, primarily within the CNS.

Types of Glial Cells in CNS

Astrocytes: Maintain blood-brain barrier and support neurons.
Oligodendrocytes: Produce myelin in the CNS, capable of myelinating multiple axons simultaneously.
Ependymal Cells: Line brain cavities, their cilia help circulate cerebrospinal fluid.
Microglia: Act as immune cells in the CNS, cleaning debris.

Satellite Cells

Surround neuron cell bodies in PNS ganglia, regulating the chemical environment.

Nerve Impulse

Electrical signal transmitted from one neuron to another; also termed action potential.

Action Potential Phases

Polarization: Neuron's resting state with a more negative interior.
Depolarization: Sodium ions influx into the neuron activates impulse.
Repolarization: Following depolarization, potassium ions exit the neuron.
Refractory Period: Period where second action potential cannot occur; ensures unidirectional signal transmission.

Saltatory Conduction

Impulse jumps between Nodes of Ranvier, enhancing speed and efficiency of signal transmission.

Synapse and Communication

Synaptic Cleft: The gap between two neurons, where neurotransmitters transmit signals.
Neurotransmitters: Chemicals (like Acetylcholine and Norepinephrine) that relay messages across synapses.
Receptor Sites: Specific sites on the receiving neuron that bind with neurotransmitters, initiating a response.

Events at Synapse

Sequential process: nerve impulse travels to axon terminal, neurotransmitter release, binding to receptors, and transmission of signal to the next neuron.

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Description

Explore the essential components and functions of the nervous system in this quiz. You will learn about the central and peripheral nervous systems, major brain regions, and the types of cells involved. Test your knowledge on how these systems communicate and process information.