Nervous System Lesson 9

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Questions and Answers

Which of the following is NOT a morphological division of the nervous system?

Somatic Nervous System (correct)

Peripheral Nervous System

Central Nervous System

Autonomic Nervous System

What is the primary function of dendrites in a neuron?

To release neurotransmitters

To maintain the structure of the neuron

To conduct impulses away from the cell body

To transmit impulses toward the cell body (correct)

Which neurotransmitter is primarily involved in the communication at the neuromuscular junction?

Serotonin

Epinephrine

Norepinephrine

Acetylcholine (correct)

What occurs during the action potential in a neuron?

Cell membrane becomes positively charged compared to the outside Signup and view all the answers

What role do neuroglia serve in the nervous system?

Support and protect neurons Signup and view all the answers

How many pairs of cranial nerves are there in the human body?

12 pairs Signup and view all the answers

Which type of muscle is innervated by the visceral efferent division of the nervous system?

Both B and C Signup and view all the answers

What is the function of axons in neurons?

Conduct impulses away from the cell body Signup and view all the answers

What is the primary function of the lens in the eye?

To change its shape for proper light focusing Signup and view all the answers

What happens to light rays that are close to the eye?

They scatter and diverge Signup and view all the answers

Where do nasal fibers of the optic nerve decussate?

At the optic chiasm Signup and view all the answers

What is the name of the area where the visual pathway terminates?

Calcarine area Signup and view all the answers

What structure is primarily responsible for secreting earwax?

Ceruminous glands Signup and view all the answers

What role does the ciliary body play in vision?

It contracts to change lens shape for accommodation. Signup and view all the answers

Which part of the eye is set for distant vision by default?

Lens Signup and view all the answers

What is the primary role of the Eustachian tube in the middle ear?

To connect the middle ear and nasopharynx Signup and view all the answers

Which structure is considered the receptor for hearing?

Organ of Corti Signup and view all the answers

What does the optic tract consist of?

Fibers from the optic chiasm to the lateral geniculate bodies Signup and view all the answers

What type of deafness is caused by damage to the cochlear nerve or hair cells?

Sensorineural Deafness Signup and view all the answers

Which fluid fills the bony labyrinth of the inner ear?

Perilymph Signup and view all the answers

What part of the cochlea initiates the process of sound wave stimulation?

Oval window Signup and view all the answers

Which condition may lead to conduction deafness?

Ruptured eardrum Signup and view all the answers

Which components are part of the membranous labyrinth?

Cochlear duct and semicircular ducts Signup and view all the answers

What action occurs when the hair cells in the organ of Corti are stimulated?

They transmit impulses to the auditory cortex Signup and view all the answers

What is the location of the third ventricle?

In the center of the diencephalon between the two thalami Signup and view all the answers

Which structure is located posteriorly to the fourth ventricle?

Cerebellum Signup and view all the answers

Which of the following is true about the dura mater?

It has two portions: cranial and spinal Signup and view all the answers

Which space is filled with a small amount of serous fluid and is located between the dura mater and the arachnoid mater?

Subdural space Signup and view all the answers

What is the expected result of Weber's Test in a normal individual?

Sound appears in the midline. Signup and view all the answers

What is the primary function of cerebrospinal fluid?

To act as a water cushion protecting the brain and spinal cord Signup and view all the answers

Which layer of the meninges is described as having a spider web appearance?

Arachnoid mater Signup and view all the answers

In Rinne’s Test, what does it indicate if bone conduction is greater than air conduction?

Conductive hearing loss. Signup and view all the answers

Which receptor is primarily stimulated by linear acceleration in the vestibular system?

Macula. Signup and view all the answers

What type of tissue primarily composes the pia mater?

Loose connective tissue Signup and view all the answers

Which structures communicate with the subarachnoid space through openings?

Luschka and Magendie Signup and view all the answers

Which cranial nerve is involved in transmitting vestibular information to the central nervous system?

Cranial nerve VIII. Signup and view all the answers

What is the main function of the vestibular system?

Maintain body balance. Signup and view all the answers

Which structure within the vestibular system contains otoliths that assist in detecting linear acceleration?

Otolithic membrane. Signup and view all the answers

What is the role of the medial vestibular nucleus?

Coordinates eye movement. Signup and view all the answers

Where is the olfactory epithelium located?

In the upper 1/3 of the nasal mucosa. Signup and view all the answers

Study Notes

Morphological Divisions of the Nervous System

Central Nervous System (CNS): Comprises the brain and spinal cord.
Peripheral Nervous System (PNS): Includes 12 pairs of cranial nerves, 31 pairs of spinal nerves, and the autonomic nervous system.

Functional Divisions of the Nervous System

Somatic Efferent: Innervates skeletal muscles and skin.
Visceral Efferent: Innervates involuntary structures like smooth and cardiac muscles, as well as glands.

Cell Types in the Nervous System

Neurons: Conduct electrical impulses; essential active components.
Neuroglia: Supporting cells that maintain homeostasis and structure.

Neurons

Basic unit conducting electrical signals throughout the body.
Contains a perikaryon (cell body) and processes (dendrites and axons).

Processes of Neurons

Dendrites: Short, branch-like structures that receive impulses toward the cell body.
Axons: Long, singular extensions that transmit impulses away from the cell body.

Synapse

Connection points between neurons; axons release neurotransmitters for signal transmission.
Main neurotransmitters include:
- Epinephrine (adrenaline)
- Norepinephrine (noradrenaline)
- Acetylcholine (at neuromuscular junctions).

Nerve Impulse

Action potential: Localized change in electric charge across the neuron membrane due to shifts in sodium and potassium ions following stimulation.

Ventricles of the Brain

Third Ventricle: Slit-like cavity between the thalami, continuous with the cerebral aqueduct.
Fourth Ventricle: Located between cerebellum and brainstem, communicating with the subarachnoid space.

Meninges

Protective membranes around the brain and spinal cord, structured as:
- Dura Mater: Tough outer layer with cranial and spinal portions.
- Arachnoid Mater: Delicate middle layer with a spider web appearance.
- Pia Mater: Vascular innermost layer that closely covers the brain surface.

Cerebrospinal Fluid (CSF)

Clear fluid circulating within the brain and spinal cord, about 150 ml in volume, acting as a cushion for protection.

Visual Pathway

Optic nerve contains nasal and temporal fibers; nasal fibers decussate at the optic chiasm.
Lateral geniculate bodies serve as the last relay stations before fibers project to the primary visual area (Brodmann's Area 17).

Auditory Sense

Outer Ear: Comprises the pinna, external auditory canal, and tympanic membrane.
Middle Ear: Contains the ossicles (malleus, incus, stapes) connecting to the Eustachian tube.
Inner Ear: Includes the cochlea, semicircular canals, and vestibule; contains fluid-filled structures that facilitate hearing and balance.

Mechanism of Hearing

Sound waves reach the cochlea, stimulating hair cells in the organ of Corti which transmit impulses to the auditory cortex.

Types of Deafness

Conduction Deafness: Results from issues with sound transmission in the external or middle ear.
Sensorineural Deafness: Caused by damage to receptor cells or auditory pathways; can be age-related or due to loud sounds.

Tests for Hearing Loss

Weber’s Test: Identifies conduction vs. sensorineural deafness based on sound lateralization.
Rinne’s Test: Compares air and bone conduction; normal air conduction is expected.

Vestibular Sense

Receptors in the inner ear contribute to balance and spatial orientation, transmitting signals via the 8th cranial nerve.
Dynamic functions are mediated by semicircular canals, while static functions are monitored by the utricle.

Olfactory Sense

Olfactory epithelium detects chemicals dissolved in mucus, sending impulses to the olfactory cortex in the temporal lobe (Brodmann's Area 34).

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Description

Test your understanding of the nervous system in this quiz based on Lesson 9 by Efreim Louie Sombillo Ilano. Explore the morphological and functional divisions of the nervous system, including the central and peripheral nervous systems. Challenge yourself with questions about cranial and spinal nerves.