Neuroanatomy Chapter 5 Quiz

Questions and Answers

What is the function of the dorsal horns in the spinal cord?

They contain cell bodies of upper motor neurons.

They connect the spinal cord to the thalamus.

They receive axons of sensory neurons. (correct)

They send out axons of motor neurons.

Which statement describes the pathway of the upper motor neuron (UMN)?

The UMN resides entirely in the spinal cord.

The UMN relays signals from the motor cortex to the ventral horn. (correct)

The UMN connects directly to the muscle unit.

The UMN is responsible for sensory input integration.

What is the sequence of neurons involved in sensory pathways from receptor to perception?

One neuron that directly conveys information to the cortex.

Two neurons: first order and second order.

Three neurons: first order, second order, and third order. (correct)

Four neurons including the interneuron.

In motor pathways, where is the cell body of the lower motor neuron (LMN) located?

In the ventral horn. Signup and view all the answers

What is true about the representation of bodily sensations and movements in the cerebral hemispheres?

Each hemisphere controls movements of the contralateral side of the body. Signup and view all the answers

What primarily distinguishes sensory nerves from motor nerves?

Sensory nerves carry impulses to the CNS. Signup and view all the answers

Which part of the nervous system processes and integrates information?

Central Nervous System Signup and view all the answers

Which of the following cranial bones is not part of the neurocranium?

Maxillae Signup and view all the answers

What are the primary components of the brainstem?

Medulla Oblongata, Pons, Midbrain Signup and view all the answers

What is the primary function of efferent neurons?

Conduct impulses away from the CNS. Signup and view all the answers

Which structure is primarily responsible for connecting the spinal cord to the cerebral hemispheres?

Brainstem Signup and view all the answers

What is characterized by being rich in myelinated fibers?

White matter Signup and view all the answers

Which division of the Peripheral Nervous System is responsible for voluntary control of skeletal muscle?

Somatic nervous system Signup and view all the answers

How are tracts usually named in the nervous system?

According to the direction of impulses Signup and view all the answers

What do you call the groups of nerve cell bodies with similar anatomical connections and functions?

Nuclei Signup and view all the answers

Study Notes

Nervous System Overview

Divisions: Central Nervous System (CNS) consists of the brain and spinal cord. Peripheral Nervous System (PNS) links CNS with peripheral structures and includes cranial and spinal nerves.
Types of Neurons: Afferent neurons carry information from peripheral receptors to CNS. Efferent neurons transmit impulses away from CNS to muscles.

Spinal Cord Anatomy

Dorsal Horns: Receive axons from sensory (afferent) neurons.
Ventral Horns: Send axons from motor (efferent) neurons to muscles.

Sensory Pathways

Composed of three neurons:
- First Order (Primary) Neuron: Cell body in a ganglion, sends axon into the spinal cord or brainstem.
- Second Order (Secondary) Neuron: Located in CNS, projects to contralateral thalamus.
- Third Order (Tertiary) Neuron: Cell body in thalamic nucleus, projects to ipsilateral primary somatosensory cortex.

Motor Pathways

Involve two neurons:
- Upper Motor Neuron (UMN): Located in motor cortex, decussates in the brainstem and relays signals to the spinal cord.
- Lower Motor Neuron (LMN): Located in ventral horn, projects to muscle unit, integrating inputs from various brainstem areas and sensory receptors.

Crossover Mechanism

Each cerebral hemisphere perceives sensations from and controls movements of the contralateral side of the body, suggesting neural crossover theories exist.

Types of Nerves

Sensory Nerves: Primarily contain sensory neurons.
Motor Nerves: Mainly consist of motor neurons.
Mixed Nerves: Have an equal mix of sensory and motor neurons.

Structure of the Brain

Composed of cerebrum, cerebellum, and brain stem.
Cerebrum: Contains lobes, gyri, and sulci, named after the skull bones they underlie.

Skull Anatomy

Cranial Bones: Divided into neurocranium (protects the brain) and viscerocranium (forms facial structure).
Neurocranial Bones: Include parietal, temporal, frontal, occipital, sphenoid, and ethmoid bones.
Viscerocranial Bones: Include nasal, maxillae, palatine, lacrimal, inferior nasal conchal, zygomatic, vomer, and mandibular bones.

Skull Sutures and Fontanelles

Sutures are fibrous joints in the skull that remain unfused at birth (fontanelles).

Cerebellum

Known as “little brain” located in the posterior cranial fossa below occipital lobes and behind the brainstem.

Brainstem Functionality

Connects spinal cord to cerebral hemispheres, comprised of the medulla oblongata, pons, and midbrain.

Grey Matter vs White Matter

Grey Matter: Rich in nerve cell bodies, located on the surface of the cerebral hemispheres and central portion of the spinal cord.
White Matter: Rich in myelinated nerve processes, primarily found deeper within the brain.

Nuclei and Tracts

Nuclei: Groups of nerve cell bodies with similar functions and anatomical connections.
Tracts: Bundles of nerve processes with common connections, often named based on impulse direction.

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Description

Test your knowledge on the functions of the spinal cord, including the dorsal horns, upper motor neurons, and sensory pathways. Explore the sequence of neurons involved in sensory perception and the location of lower motor neuron cell bodies. Understand how bodily sensations and movements are represented in the cerebral hemispheres.