Neuroscience Basics: Glial Cells and Neurons

Questions and Answers

Which part of a neuron is responsible for receiving nerve impulses?

Dendrites (correct)

Soma

Axon

Myelin sheath

What is the primary function of neurons?

To transmit information (correct)

To support the immune system

To facilitate digestion

To produce hormones

What is the main distinction between motor neurons and sensory neurons?

Motor neurons originate from the periphery, sensory neurons from the CNS

Motor neurons transmit sensory impulses, sensory neurons do not

Motor neurons have dendrites, sensory neurons do not

Motor neurons have long axons; sensory neurons have axons with receptors (correct)

What are intrinsic neurons characterized by?

Being confined to the same level and side of the CNS Signup and view all the answers

Which structure is found in both motor and sensory neurons but is differently organized?

Cell body Signup and view all the answers

What type of neuron typically crosses to the opposite side of the body?

Commissural neuron Signup and view all the answers

What aspect of neurons contributes to their functional diversity?

Size and shape variations Signup and view all the answers

Which of the following sensory organs is NOT paired with its correct sense?

Ear - Smell Signup and view all the answers

What is characteristic of unipolar neurons?

They possess a spherical soma with a single bifurcating process. Signup and view all the answers

Which type of neuron is described as having a pyramid shape and is the largest neuron cell?

Pyramidal neurons. Signup and view all the answers

What defines a pseudo unipolar neuron?

It features a single process that divides into two distinct branches. Signup and view all the answers

Which type of neuron primarily acts as inhibitory neurons with multiple dendrites?

Purkinje neurons. Signup and view all the answers

What is the typical cytoplasmic ratio of giant neurons?

0.5:1. Signup and view all the answers

Study Notes

Glial Cells and Neurons Overview

Neurons are the basic functional unit of the brain, primarily responsible for transmitting information.
Mammalian brains contain approximately 100 billion neurons.
Neurons interact with glial cells, which support and protect neurons.

Neuron Structure

The neuron consists of a cell body (soma) that generates two types of cell processes:
- Dendrites: Receive nerve impulses from sensory cells or other neurons.
- Axon: Conveys signals to other cells.
The soma contains essential organelles like the nucleus, endoplasmic reticulum, Golgi apparatus, and mitochondria.

Diversity in Neurons

Neurons vary in size and shape, exemplified by:
- Pyramidal cells in the cerebral cortex.
- Purkinje cells in the cerebellar cortex.
- Olfactory cells in the olfactory epithelium.

Functional Classification of Neurons

Interneurons: Connect different neurons within the CNS.
Motor Neurons: Carry impulses from the CNS to effectors (muscles/glands).
Sensory Neurons: Transmit sensory information from sensory organs to the CNS.

Motor and Sensory Neuron Differences

Motor Neuron Characteristics:
- Long axons with multiple short dendrites.
- Cell body located at the terminal end.
Sensory Neuron Characteristics:
- Short axon with receptor cells located alongside the soma.
- Typically lacks dendrites.

Neuron Projections

Neurons can decussate (cross over) to the opposite side of the body or remain ipsilateral (on the same side).

Types of Neurons

Unipolar Neurons:
- Spherical soma with a single process that divides into two branches.
- Common in invertebrate interneurons.
Bipolar Neurons:
- Have one axonal and one dendritic process.
- Often involved in sensory functions.
Multipolar Neurons:
- Feature many dendritic processes and a single axon.
- Predominantly found in interneurons and motor neurons.
Pseudo-Unipolar Neurons:
- Possess a single process from the soma that branches into two distinct structures.
- Typical in sensory neurons, connecting to dendrites and transmitting information to the spinal cord.

Neuron Size and Structure

Small Neurons: Diameter around 3 micrometers, with a nucleus to cytoplasm ratio close to 1; examples include globuli cells of invertebrates.
Giant Neurons: Diameter can reach 1000 micrometers, with a nucleus to cytoplasm ratio of 0.5; examples include neurons found in marine gastropods.

Purkinje Neurons

Found in the cerebellum, these inhibitory neurons have multiple dendrites and release neurotransmitters that prevent excessive neuronal firing.

Description

Explore the fundamental components of the brain, focusing on glial cells and neurons. Understand their structure, functions, and how they transmit information. This quiz will test your knowledge on the basic workings of these essential brain units.