MD137 Introduction to Electrophysiology

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Questions and Answers

What is the primary function of neuroglial cells?

Coordinating muscle movements

Generating electrical impulses

Transmitting signals between neurons

Providing physical support and nutrients for neurons (correct)

Which type of neuron is responsible for carrying messages toward the brain?

Interneurons

Motor neurons

Pyramidal neurons

Sensory neurons (correct)

What distinguishes unipolar neurons from bipolar and multipolar neurons?

They are only found in the spinal cord

They possess a single stalk that splits into two branches (correct)

They do not transmit signals

They have multiple dendritic trees

What is the function of dendrites in a neuron?

To receive information from other neurons Signup and view all the answers

Which of the following statements is true regarding neurons' energy usage?

Neurons use 20% of the body's energy but weigh less than 2% Signup and view all the answers

What role do interneurons serve in the nervous system?

They connect sensory and motor neurons Signup and view all the answers

What is the name given to the gaps found in the myelin sheath of larger axons?

Nodes of Ranvier Signup and view all the answers

Which neuron type can be classified as either excitatory or inhibitory based on the neurotransmitter they release?

Interneurons Signup and view all the answers

Which part of the nervous system is responsible for gathering information about changes occurring within and around the body?

Sensory nervous system Signup and view all the answers

What is the primary component of the Central Nervous System (CNS)?

Brain and spinal cord Signup and view all the answers

Which system is NOT part of the Peripheral Nervous System (PNS)?

Central nervous system Signup and view all the answers

What is the main function of the autonomic nervous system?

Regulate involuntary bodily functions Signup and view all the answers

Which option describes the parasympathetic nervous system's function?

Promotes digestion and pupil dilation Signup and view all the answers

What function does the somatic nervous system primarily serve?

Facilitates two-way communication between CNS and peripheral organs Signup and view all the answers

What statement is true regarding the regenerative capacity of the Central Nervous System compared to the Peripheral Nervous System?

CNS has limited regenerative capacity; PNS has some Signup and view all the answers

Which of the following accurately describes nerves in the nervous system?

Nerves are bundles of axons Signup and view all the answers

Study Notes

Introduction to Electrophysiology

The lecture covers the structure and function of cells in the nervous system.
The course is MD137, Introduction to Physiology, at the University of Galway.
The lecturer is Leo Quinlan.

Learning Outcomes

Understand the basic organization of the nervous system.
Identify the cells of the nervous system and their function(s).
Describe the structure-function relationships within a neuron.
Detail the functions of the three main parts of a neuron.

Functional Organisation of the Nervous System

Sensory: Gathers information about changes inside and outside the body (e.g., light, oxygen levels, body temperature). Signals are sent to the Central Nervous System (CNS).
Integrative: Processes the sensory information; interprets, creates sensations, thoughts, memories, and makes decisions.
Motor: Sends signals to muscles or glands to elicit a response.

Central Nervous System (CNS)

The CNS is comprised of the brain and spinal cord.
Regenerative capacity is limited if damaged.

Peripheral Nervous System (PNS)

Made up of nerves connecting the CNS to the rest of the body
The PNS has some capacity for regeneration.
Components of the PNS are divided into 2 parts:
- Autonomic nervous system
- Somatic nervous system

Autonomic Nervous System

Divided into two branches:
- Parasympathetic: "rest and digest"
  - Decreases heart rate, bronchiole dilation, blood glucose, blood to skeletal muscle
  - Increases digestion, pupillary size, urinary output.
- Sympathetic: "fight or flight"
  - Decreases digestion, pupillary size, urinary output
  - Increases heart rate, bronchiole dilation, blood glucose, blood to skeletal muscle

Somatic Nerves

All nerves outside the autonomic nervous system, outside the CNS
Two-way communication
Connect the CNS to the peripheral end organs (skin and muscles)
Connect the peripheral end organs (skin and muscles) to the CNS

Cells of the Nervous System

Wide array of cell types
Billions of interconnections
Neurons are cable-like bundles of axons.
Neuroglial cells provide support, insulation (myelin), and nutrients for neurons

Neurons

Base unit of the nervous system
Simple function to decide whether to transmit a signal.
Billions of neurons (estimated 100 billion)
Complex interconnections
Create systems/circuits able to function independently (parallel processing)
"Simple decisions" passed to "higher" levels for additional processing
Very expensive, using approximately 20% of the body's energy in spite of representing only 2% of body mass.

Types of Neurons - Function

Sensory neurons: Carry messages to the brain.
Motor neurons: Carry messages to muscles.
Interneurons (e.g., pyramidal): Connect other neurons.
Can be excitatory or inhibitory depending on the neurotransmitter they release.

Types of Neurons - Anatomy

Classified based on axonal outgrowths.
- Unipolar: One stalk that splits into two branches
- Bipolar: One axon, one dendritic tree
- Multipolar: One axon, many dendritic branches

Networks of Neurons - Neural Circuit

Networks of neurons are interconnected.

Networks of Neurons - Reflex

Reflexes are rapid, automatic responses to stimuli.
A sequence of neural events.

Typical Neuron

Made up of cell body, dendrites, and axons.
Dendrites receive information.
Axons send information.
Larger axons are enclosed by myelin sheaths produced by Schwann cells.
Narrow gaps in the myelin sheath between Schwann cells are called nodes of Ranvier.

Cells of Glial Nervous System

Glial cells support neurons.
- Satellite cells (PNS)
- Schwann cells (PNS)
- Oligodendrocytes (CNS)
- Astrocytes (CNS)
- Microglia (CNS)
- Ependymal cells (CNS)

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Description

This quiz focuses on the basics of electrophysiology, covering the structure and function of the nervous system's cells. It includes essential concepts regarding the organization and roles of sensory, integrative, and motor functions. Test your understanding of neurons and the central nervous system with this quiz.