Nervous System Overview

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Questions and Answers

What is the primary function of the sensory (afferent) division of the peripheral nervous system?

To regulate involuntary muscle movements

To transmit signals between brain regions

To carry impulses to the central nervous system (correct)

To initiate responses from skeletal muscles

Which part of the nervous system is responsible for voluntary responses?

Somatic nervous system (correct)

Autonomic nervous system

Central nervous system

Sensory division

What is a key role of the autonomic nervous system?

To transmit sensory information from the body

To facilitate reflex actions in skeletal muscles

To manage involuntary functions like digestion (correct)

To control voluntary muscular contractions

What function is primarily associated with the sympathetic division of the autonomic nervous system?

Initiating 'fight or flight' responses Signup and view all the answers

Which of the following correctly describes the relationship between the central nervous system and the peripheral nervous system?

The PNS connects the CNS to all body parts. Signup and view all the answers

What is the primary role of neurons in the nervous system?

To transmit neural impulses Signup and view all the answers

Which type of neuron is primarily responsible for the analysis and organization of information in the nervous system?

Interneurons Signup and view all the answers

Which component of a neuron contains the nucleus and organelles?

Cell body Signup and view all the answers

What type of receptors are responsible for sensing temperature changes?

Thermoreceptors Signup and view all the answers

Which sensory receptors are specifically sensitive to light touch stimuli?

Meissner’s corpuscles Signup and view all the answers

In which part of the body are olfactory receptors located?

Roof of nasal cavity Signup and view all the answers

What type of receptors detect pain in the body?

Free nerve endings Signup and view all the answers

What is the main function of taste cells in the taste buds?

To detect chemicals dissolved in saliva Signup and view all the answers

Which type of sensory receptors are involved in the sensation of taste?

Chemoreceptors Signup and view all the answers

What type of sensations are stimulated when tissue is damaged?

Pain sensations Signup and view all the answers

Which taste receptors respond specifically to metal ions?

Salty receptors Signup and view all the answers

What is the primary function of ceruminous glands in the outer ear?

To secrete cerumen as a trap for foreign particles Signup and view all the answers

Which of the following correctly lists the ossicles in order from the outer to the inner ear?

Malleus, Incus, Stapes Signup and view all the answers

What mechanism opens the Eustachian tube to equalize pressure in the middle ear?

Yawning and swallowing Signup and view all the answers

What type of receptors are responsible for detecting sound vibrations?

Mechanoreceptors Signup and view all the answers

Which fluid fills the space between the bony labyrinth and the membranous labyrinth in the inner ear?

Perilymph Signup and view all the answers

What do efferent nerves primarily do?

Carry impulses away from the CNS Signup and view all the answers

Which of the following is a noninflammatory disorder?

Cerebrovascular accidents Signup and view all the answers

What condition results from the progressive degeneration of myelin sheaths in the CNS?

Multiple sclerosis Signup and view all the answers

Which disorder is characterized by brief loss of consciousness due to decreased blood flow to the brain?

Fainting Signup and view all the answers

What is the primary cause of Parkinson's disease?

Insufficient production of dopamine Signup and view all the answers

What condition results from the malfunctioning of the language center in the brain?

Dyslexia Signup and view all the answers

Which of these symptoms is associated with Alzheimer's disease?

Loss of memory Signup and view all the answers

What is the most common result of the interaction of illness, trauma, or genetic factors in epilepsy?

Seizures Signup and view all the answers

Which type of nerve is primarily responsible for sensory functions?

Afferent nerves Signup and view all the answers

What type of headache is associated with changes in blood vessel dilation within the meninges?

Migraine headache Signup and view all the answers

What is the primary structure in the cochlea responsible for hearing?

Organ of Corti Signup and view all the answers

Which structure is responsible for receiving vibrations from the oval window?

Basilar membrane Signup and view all the answers

What do the otoliths do in the vestibule?

Bend the hair cells in the macula Signup and view all the answers

What type of equilibrium is maintained when the head is motionless?

Static equilibrium Signup and view all the answers

Which part of the ear transmits vibrations to the inner ear?

Ossicles Signup and view all the answers

Which membrane is essential for bending hair cells in response to vibrations from the basilar membrane?

Tectorial membrane Signup and view all the answers

What function does the macula serve in the vestibule?

Organ for static equilibrium Signup and view all the answers

Which structure is NOT involved in the hearing mechanism?

Utricle Signup and view all the answers

What is the role of the ciliary body in vision?

Adjusts the shape of the lens to focus light Signup and view all the answers

Which condition is characterized by the clouding of the lens?

Cataract Signup and view all the answers

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

Neural deafness Signup and view all the answers

What is retinoblastoma?

Cancer of immature retinal cells Signup and view all the answers

Which condition involves unequal focusing of light rays on the retina?

Astigmatism Signup and view all the answers

What sensation may be caused by labyrinthine disease?

Dizziness and nausea Signup and view all the answers

What does myringoscopy allow a physician to do?

Inspect the eardrum Signup and view all the answers

Which of the following disorders is typically characterized by a total or partial loss of vision?

Blindness Signup and view all the answers

What does hyperopia refer to?

Inability to see close objects clearly Signup and view all the answers

Which term describes inflammation of the middle ear?

Otitis media Signup and view all the answers

What is the primary cause of glaucoma?

Improper drainage of aqueous humor Signup and view all the answers

What does presbyopia result from?

Decreased elasticity of the lens Signup and view all the answers

Which part of the eye is responsible for controlling the amount of light that enters?

Iris Signup and view all the answers

What is the significance of ciliary muscles in vision?

They help in adjusting the lens shape Signup and view all the answers

Study Notes

Nervous System

The nervous system is the primary controlling system of the body, using electrochemical impulses to communicate.
It performs three key functions:
- Detecting internal and external changes (stimuli) - accomplished by receptors.
- Analyzing and organizing the received information (control center).
- Initiating appropriate actions (effectors).
The nervous system is divided into two major parts:
- Central nervous system (CNS): Comprises the brain and spinal cord, acting as the control center.
- Peripheral nervous system (PNS): Composed of nerves outside the CNS; carries impulses from receptors to the CNS and from the CNS to effectors.
The PNS is further divided into:
- Sensory (afferent) division: Carries impulses to the CNS.
- Motor (efferent) division: Carries impulses away from the CNS.
  - Somatic nervous system (SNS): Controls voluntary movements of skeletal muscles.
  - Autonomic nervous system (ANS): Controls involuntary movements of smooth muscles, cardiac muscles, and glands.
    - Sympathetic division: Primarily involved in "fight-or-flight" responses, increasing activity during stress or exercise.
    - Parasympathetic division: Primarily involved in "rest-and-digest" functions, helping conserve energy during normal activities.

Neurons

Neurons are specialized cells for transmitting neural impulses, constituting the structural and functional unit of the nervous system.
Major neuron components:
- Cell body: Contains the nucleus and other organelles except centrioles.
- Dendrites: Short, branched processes extending from the cell body receiving impulses.
- Axons (nerve fibers): Long, thin processes that transmit impulses away from the cell body.
- Myelin sheath: Insulating covering of axon formed by neuroglial cells; facilitates faster impulse transmission.
- Nodes of Ranvier: Tiny spaces between the myelin sheath where the axon is exposed; crucial for saltatory conduction (faster impulse transmission).
- Axon terminals: Ends of axons; contain synaptic knobs for transmitting the signal to other neurons or effectors.
Types of neurons based on function:
- Sensory (afferent) neurons: Carry impulses from sensory receptors to the CNS.
- Interneurons: Located entirely within the CNS; process and interpret impulses.
- Motor (efferent) neurons: Carry impulses from the CNS to effectors (muscles and glands).

Nerve Impulses

Neurons exhibit irritability (the ability to detect and respond to stimuli) and conductivity (the ability to transmit impulses).
An un-stimulated neuron maintains a resting potential (unequal distribution of electrical charges inside vs outside the cell) through sodium/potassium pump.
Stimulus triggers an action potential or impulse: sodium flooding the cell, causing depolarization and changes in charge.
Repolarization immediately follows, as potassium ions leave the cell, restoring the original charge difference.
The sodium-potassium pump then re-establishes resting potential.
Neurons exhibit an "all-or-none" response (a weak or strong impulse are both equal in strength, only the stimulus causing is different)

Synaptic Transmission

Synapses are junctions where axons connect with other neurons or effectors (muscle or gland cells).
Synaptic transmission involves neurotransmitters (chemicals) across the synaptic cleft, stimulating the adjacent neuron or effector.

Protection for the Central Nervous System

Meninges: Three connective tissue membranes protecting CNS structures.
- Dura mater: Outermost, tough layer.
- Arachnoid layer: Middle, web-like layer.
- Pia mater: Innermost, attaches to the brain.
Cerebrospinal fluid (CSF): Watery cushion protecting the nervous tissue, found within ventricles and meninges.

The Brain

Four major regions of the brain:
- Cerebrum: Largest part of the brain performing higher brain functions (sensation, voluntary actions, reasoning, planning, etc.); divided into four lobes.
- Diencephalon: Contains the thalamus (relay station for sensory impulses) and hypothalamus (major control center for the autonomic nervous system).
- Brain stem: Includes midbrain, pons, and medulla oblongata; crucial for basic life functions (breathing, heart rate, etc.).
- Cerebellum: Coordinates skeletal muscle activities for posture, balance, and coordination.

Nerves

Bundles of axons (nerve fibers) with supporting connective tissues (endoneurium, perineurium, epineurium).
Spinal and cranial nerves - mixed, Afferent (sensory), and Efferent (motor) types.

Special Senses

Receptors are chemoreceptors (detect chemicals) or mechanoreceptors (detect movement).
General senses include temperature, pain, pressure, and touch.
Special senses include taste, smell, hearing, and vision.
Detailed information about particular senses like taste, smell, hearing, and vision is present.

Disorders of the Nervous System

Different sections describe different disorders affecting the system, such as inflammatory disorders and noninflammatory disorders.

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Description

This quiz provides an overview of the nervous system, including its main functions and divisions. Learn about the central and peripheral nervous systems, as well as the roles of sensory and motor divisions. Test your understanding of how the body communicates through electrochemical impulses.