Neuroscience: Structure of a Neuron

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Questions and Answers

What is the primary function of the plasma membrane in a cell?

To house the DNA of the cell

To facilitate protein synthesis

To separate the inside of the cell from the outside environment (correct)

To act as a conduit for electrical impulses

Which structure in a neuron is responsible for conducting impulses?

Nucleus

Ribosomes

Axon (correct)

Dendrites

What type of neuron is specialized to respond to specific stimuli such as light or touch?

Motor neuron

Glial cell

Sensory neuron (correct)

Interneuron

Which part of the neuron is primarily involved in receiving signals?

Dendrites Signup and view all the answers

What characterizes the nucleus of a cell?

It encloses DNA and controls hereditary functions Signup and view all the answers

What role do protein channels in the plasma membrane have?

They facilitate the selective passage of certain chemicals Signup and view all the answers

Which cell structure is involved in modifying and transporting proteins?

Endoplasmic reticulum Signup and view all the answers

Which component of the neuron is NOT involved in the transmission of nervous impulses?

Nucleus Signup and view all the answers

Which system is commonly referred to as the 'rest and digest' system?

Parasympathetic nervous system Signup and view all the answers

What is the primary role of the sympathetic nervous system?

Facilitate emergency responses Signup and view all the answers

What type of input do sweat glands receive?

Sympathetic only Signup and view all the answers

Which function is primarily increased by the parasympathetic nervous system?

Digestive activity Signup and view all the answers

In the spinal cord, which matter is composed largely of cell bodies?

Gray matter Signup and view all the answers

What does the term 'parasympathetic' imply?

Beside or related to sympathetic activities Signup and view all the answers

Which of the following systems decreases digestive activity?

Sympathetic nervous system Signup and view all the answers

Which structure in the spinal cord is densely packed with cell bodies?

Gray matter Signup and view all the answers

Which plane divides the body into anterior and posterior sections?

Coronal plane Signup and view all the answers

What term describes the direction towards the front of the body?

Ventral Signup and view all the answers

In which plane is the brain sectioned to observe lateral structures?

Sagittal plane Signup and view all the answers

What is the term for the section of the nervous system that includes the brainstem and spinal cord?

Central nervous system Signup and view all the answers

Which directional term refers to the tail end of a vertebrate organism?

Caudal Signup and view all the answers

Which anatomical division typically includes the motor functions of the body?

Somatic nervous system Signup and view all the answers

What does the term 'dorsal' refer to in anatomical positioning?

Back side of the body Signup and view all the answers

Which plane can be used to view both medial and lateral aspects of the brain?

Sagittal plane Signup and view all the answers

What is the anatomical position of a structure that is towards the midline of the body?

Medial Signup and view all the answers

Which directional term refers to a structure closer to the point of attachment of a limb?

Proximal Signup and view all the answers

Which anatomical term best describes the underside of the brain?

Ventral Signup and view all the answers

Which coordinate system divides the body into superior and inferior sections?

Horizontal plane Signup and view all the answers

What does the 'medial' direction indicate about the location of a structure?

Towards the midline Signup and view all the answers

Which of the following appropriately describes the region towards the upper part of the brain?

Dorsal Signup and view all the answers

What role does the axon primarily serve in a neuron?

To convey impulses toward other neurons, organs, or muscles Signup and view all the answers

What characteristic distinguishes the length of an axon?

It can be more than a meter in length Signup and view all the answers

Where is the cell body of a motor neuron located?

In the spinal cord Signup and view all the answers

How does the width of an axon compare to its length?

Axons are significantly longer than they are wide Signup and view all the answers

What is the primary function of the parasympathetic nervous system?

Facilitating sexual arousal and erection in males Signup and view all the answers

What is the primary function of the myelin sheath?

To insulate the neuron and increase impulse speed Signup and view all the answers

What happens when a segment of the spinal cord is cut?

Sensation from that segment and below is lost Signup and view all the answers

What are the small fuzzy-looking spines on dendrites thought to do?

They increase the surface area for receiving signals Signup and view all the answers

What does the term 'axon' derive from in Greek?

Axis Signup and view all the answers

What is another name for the parasympathetic nervous system?

Craniosacral system Signup and view all the answers

What part of the neuron is responsible for generating the impulse?

Axon hillock Signup and view all the answers

How are the ganglia of the parasympathetic nervous system arranged?

Close to each internal organ Signup and view all the answers

What type of axons extend from the spinal cord to parasympathetic ganglia?

Long preganglionic axons Signup and view all the answers

What neural structures are responsible for transmitting commands from the brain to the internal organs?

Sympathetic and parasympathetic systems Signup and view all the answers

Which of the following statements is true regarding the sympathetic and parasympathetic systems?

Both systems are constantly active to varying degrees Signup and view all the answers

What is the primary purpose of short postganglionic fibers in the parasympathetic system?

To transmit commands directly to internal organs Signup and view all the answers

Study Notes

Cell Membrane and Neurons

The plasma membrane separates the internal environment of the cell from the external environment.
Most chemicals cannot cross the membrane; only certain protein channels facilitate this process.
A sensory neuron is designed to be highly sensitive to specific stimuli like light, sound, or touch.

Neuron Structure

Neurons consist of dendrites, which receive signals, and an axon, which conducts impulses to muscles or other neurons.
Axons can exceed one meter in length, particularly those extending from the spinal cord to the feet.
The axon is significantly longer than its diameter, with unique anatomical features like the myelin sheath, which enhances signal transmission.

Nervous System Organization

The spinal cord contains gray matter (cell bodies and dendrites) and surrounding white matter (myelinated axons).
Each spinal cord segment processes sensory input and motor commands, facilitating communication between the brain and body.

Autonomic Nervous System

The autonomic nervous system regulates involuntary bodily functions, with both sympathetic and parasympathetic components.
The sympathetic system prepares the body for emergency responses, increasing heart rate and decreasing digestive activity.
The parasympathetic system is responsible for "rest and digest" functions, countering sympathetic effects by lowering heart rate and increasing digestive functions.
The parasympathetic system is referred to as the craniosacral system, consisting of cranial nerves and sacral spinal cord nerves.

Neural Communication

In response to spinal cord injury, sensation and motor control below the injury site are severely affected.
Both sympathetic and parasympathetic systems are active simultaneously to regulate bodily functions, adapting to various stimuli.

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Description

This quiz explores the structure and function of neurons, focusing on the roles of the cell membrane, dendrites, and axon in conducting impulses. Test your knowledge on how sensory neurons are specialized for their roles in the nervous system.