Cranial Nerves and Nervous System Overview

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Questions and Answers

Which type of neuroglia forms a myelin sheath around nerve fibers in the central nervous system?

Microglia

Astrocytes

Ependymal cells

Oligodendrocytes (correct)

During the resting state of a neuron, the plasma membrane is considered to be ______.

Depolarized

Hyperpolarized

Polarized (correct)

Neutral

Which of the following is NOT a component of a reflex arc?

Interneuron

Motor neuron

Synapse (correct)

Sensory neuron

What is the primary function of the peripheral nervous system (PNS)?

Communication between the brain and the rest of the body (B) Signup and view all the answers

Which of the following ions is primarily responsible for depolarization during an action potential?

Sodium (Na+) (B) Signup and view all the answers

What is the role of myelin sheaths in nerve impulse transmission?

To increase the speed of nerve impulse conduction (C) Signup and view all the answers

Which of the following is a characteristic of astrocytes?

Star-shaped cells that form barriers between capillaries and neurons (C) Signup and view all the answers

Which of the following is a TRUE statement regarding the difference between the CNS and the PNS?

The CNS acts as the integration center, while the PNS acts as the communication network (D) Signup and view all the answers

Which of the following accurately pairs a brain region with its primary function?

Hypothalamus - Regulates body temperature, metabolism, and emotions (C) Signup and view all the answers

Which of the following neurotransmitters is associated with muscle contraction and is excitatory in nature?

Acetylcholine (C) Signup and view all the answers

A patient experiences a loss of sensation in their right arm. Which lobe of the brain is most likely affected?

Parietal lobe (C) Signup and view all the answers

What is the primary function of the myelin sheath that surrounds axons?

To increase the speed of nerve impulse conduction (D) Signup and view all the answers

Which of the following is NOT a characteristic of a concussion?

Permanent brain damage (C) Signup and view all the answers

Which of the following statements accurately describes the role of the sympathetic nervous system?

It prepares the body for 'fight or flight' responses (D) Signup and view all the answers

Which of the following cranial nerves is responsible for controlling eye movement?

Oculomotor (C) Signup and view all the answers

Which of the following is the primary function of the reticular activating system (RAS)?

To regulate the sleep-wake cycle and consciousness (D) Signup and view all the answers

Which of the following accurately describes the function of the thalamus?

It acts as a relay station for sensory impulses (A) Signup and view all the answers

Which of the following is NOT a characteristic of Alzheimer's disease?

Increased production of acetylcholine (A) Signup and view all the answers

Which of the following best describes the effect of stimulants on the nervous system?

They increase the activity of neurotransmitters, resulting in heightened arousal and alertness (C) Signup and view all the answers

Which of the following accurately describes the location of Broca's area?

Frontal lobe (D) Signup and view all the answers

Which of the following accurately describes the function of the pons?

It contains nuclei that control breathing (B) Signup and view all the answers

A patient with damage to the medulla oblongata would likely experience difficulty with which of the following functions?

Swallowing and breathing (C) Signup and view all the answers

Which of the following is NOT a type of protective barrier for the central nervous system (CNS)?

Myelin sheath (C) Signup and view all the answers

Which of the following neurotransmitters is associated with sleepiness and is inhibitory in nature?

Serotonin (A) Signup and view all the answers

What type of neuroglia is responsible for forming a myelin sheath around nerve fibers in the peripheral nervous system?

Schwann cells (B) Signup and view all the answers

Which of the following events occurs during the repolarization phase of an action potential?

Potassium ions (K+) move out of the neuron. (A), The neuron becomes more negatively charged. (D) Signup and view all the answers

Which of the following is NOT a characteristic of a neuron at rest?

There is a higher concentration of potassium ions (K+) inside the neuron. (A) Signup and view all the answers

What is the role of neurotransmitters in synapse transmission?

They carry the nerve impulse across the synaptic cleft and stimulate the postsynaptic neuron. (B) Signup and view all the answers

What is the primary function of the ependymal cells?

Lining the central cavities of the brain and spinal cord. (A) Signup and view all the answers

Which neuroglia functions as a phagocyte to remove cellular debris and pathogens from the CNS?

Microglia (D) Signup and view all the answers

What is the primary function of the myelin sheath in a neuron?

To increase the speed of nerve impulse transmission (A) Signup and view all the answers

Which of the following neurotransmitters is associated with muscle contraction?

Acetylcholine (C) Signup and view all the answers

Which lobe of the brain is primarily responsible for processing sensory information from the body?

Parietal lobe (B) Signup and view all the answers

What is the primary function of the hypothalamus in the brain?

Regulates body temperature and metabolism (B) Signup and view all the answers

Which of the following describes the role of the sympathetic nervous system?

Prepares the body for 'fight-or-flight' responses (A) Signup and view all the answers

A patient with damage to the medulla oblongata would likely experience difficulty with which of the following?

Breathing and heart rate (C) Signup and view all the answers

Which of the following is NOT a type of protective barrier for the central nervous system?

Myelin sheath (C) Signup and view all the answers

Which area of the brain is responsible for the ability to speak?

Broca's area (A) Signup and view all the answers

Which of the following most accurately describes the effect of stimulants on the nervous system?

They increase the release of neurotransmitters at synapses (C) Signup and view all the answers

What is the primary function of the pons?

Regulation of heart rate and breathing (C) Signup and view all the answers

Which of the following neurotransmitters is associated with a sense of well-being and is often affected by drugs like cocaine?

Dopamine (B) Signup and view all the answers

Which of the following describes the difference between a concussion and a contusion?

A concussion is a mild injury, while a contusion is more severe with possible bleeding (C) Signup and view all the answers

Which of the following accurately describes the function of the reticular activating system (RAS)?

Maintains consciousness and alertness (A) Signup and view all the answers

Study Notes

Cranial Nerves and Spheres

Cranial nerves are part of the peripheral nervous system.
Olfactory (smell), Optic (vision), Oculomotor (eye movement/pupils), Trochlear (eye movement), Trigeminal (facial sensation/chewing), Abducens (eye movement), Facial (facial expressions/taste), Vestibulocochlear (hearing/balance), Glossopharyngeal (taste/swallowing), Vagus (visceral organs), Accessory (neck muscles), Hypoglossal (tongue movements)

Central Nervous System (CNS) and Peripheral Nervous System (PNS)

CNS: Brain and spinal cord; integration center.
PNS: Nerves extending outside the brain and spinal cord; sensory (afferent) and motor (efferent) functions.
CNS Location: Central (brain and spinal cord)
CNS Function: Integration center
CNS Support Cells: Oligodendrocytes – form myelin sheath
PNS Location: Nerves extending outside the brain and spinal cord
PNS Function: Sensory (afferent) and motor (efferent)
PNS Support Cells: Schwann cells – form myelin sheath

Neuroglia (Supporting Cells of the CNS)

Neuroglia support, insulate, and protect neurons.
They cannot transmit nerve impulses and retain their ability to divide.
Astrocytes: Star-shaped, abundant, form barriers between capillaries and neurons.
Microglia: Spider-like phagocytes; dispose of debris (wastes, dead cells, bacteria).
Ependymal Cells: Line central cavities of brain and spinal cord, produce and circulate cerebrospinal fluid.
Oligodendrocytes: Found in the CNS; wrap around nerve fibers to form myelin sheaths.

Peripheral Nervous System (PNS) Glia

Schwann cells: Form myelin sheath in the peripheral nervous system.

Action Potential Mechanism

Resting State: Membrane polarized, fewer positive ions inside than outside.
Depolarization: Stimulus depolarizes membrane, allowing Na+ ions to enter, initiating action potential. All-or-none response.
Action Potential Propagation: Conducted along entire axon; faster with myelin sheaths.
Synaptic Transmission: Axon terminal releases neurotransmitters, stimulating dendrites of the next neuron.
Repolarization: Return to resting state by outward movement of K+ ions.
Resting Neuron: Plasma membrane is polarized; fewer positive ions inside the cell than outside, inactive.
Depolarization (step-by-step): Stimulus depolarizes neuron's membrane, allowing Na+ to enter the membrane. Charge upset inside the cell starts action potential.
Action Potential (step-by-step): Conducted through the axon; impulses travel faster with myelin sheaths. Signals at synapses—axon terminal releases neurotransmitters, activating the dendrite. Action potential starts from dendrite.
Repolarization (step-by-step): Return to resting state via outward movement of K+ ions.

Reflexes and Reflex Arcs

Reflexes: Rapid, involuntary responses to stimuli.
Reflex arc: Direct pathway from receptor (sensory neuron) to interneuron to motor neuron (effector).

Neuron Anatomy

Cell Body: Nucleus and metabolic center (most organelles except centrioles).
Dendrites: Conduct impulses towards the cell body.
Axons: Conduct impulses away from the cell body.
Axon Terminals: Release neurotransmitters (e.g., acetylcholine, serotonin, epinephrine, histamine) into the synaptic cleft.
Myelin Sheath: Fatty insulation around axons, increasing conduction speed.
Synaptic Cleft: Gap separating axon terminals and the next neuron.

Brain Anatomy

Cerebral Hemispheres (Cerebrum): Two halves (left & right), connected by corpus callosum.
Lobes: Frontal (motor, speech), Parietal (sensory), Occipital (vision), Temporal (sound, smell).
Specialized Areas: Primary somatic sensory area (parietal), Primary motor area (frontal), Broca's area (speech).
Diencephalon: Thalamus (sensory relay), Hypothalamus (autonomic center, body temperature, homeostasis, limbic system), Epithalamus (pineal gland, choroid plexus).
Brain Stem: Midbrain (visual/auditory reflexes), Pons (breathing), Medulla Oblongata (vital centers, heart rate, blood pressure, breathing, swallowing, vomiting).
Reticular Formation: Diffuse mass, motor control of visceral organs, reticular activating system (sleep/consciousness).
Cerebellum: Motor functions, maintaining balance and posture, coordination of voluntary movements, motor learning.

CNS Protection

Skull: Hard outer barrier.
Meninges: Connective tissue membranes.
Cerebrospinal Fluid: Watery cushion, removes waste.
Blood-Brain Barrier: Prevents many harmful substances from entering the brain.

Head Trauma and Neurological Disorders

Traumatic Brain Injuries (TBIs): Concussion (minor injury), Contusion (bruise, intracranial hemorrhage).
Cardiovascular Accidents (CVAs): Stroke (blood vessel rupture/clot), brain tissue death due to oxygen/nutrient deprivation.
Alzheimer's Disease: Progressive deterioration, abnormal protein deposits, ACh shortage, memory loss.

Somatic and Autonomic Nervous Systems

Somatic NS: Voluntary motor control.
Autonomic NS: Involuntary motor control, two divisions:
- Sympathetic (fight-or-flight)
- Parasympathetic (housekeeping)

Sympathetic & Parasympathetic Divisions

Sympathetic: "fight or flight," response to stress.
Parasympathetic: "rest and digest," conserves energy; maintains essential bodily functions (digestion, defecation, urination).

Neurotransmitters and Drugs

Neurotransmitters: Chemical messengers.
Neurotransmitters activate or inhibit postsynaptic neurons.
Acetylcholine (ACh): Muscle contraction (excitatory).
Norepinephrine: Associated with arousal (excitatory).
Dopamine: Well-being (can be excitatory or inhibitory).
Serotonin: Sleepiness (inhibitory).
GABA: Sedative effects (inhibitory).
Adenosine: Regulates sleep cycle (inhibitory).
Drugs: Affect neurotransmitter action (release, blocking receptors).
Stimulants: Increase neurotransmitter release, depleting it causing fatigue, circulatory problems, hallucinations, or depression.
Depressants: Inhibit neurotransmitter activity (e.g., barbiturates, Xanax - GABA agonists).

Cranial Nerves

Olfactory: Smell
Optic: Vision
Oculomotor: Eye movement, pupillary reflex
Trochlear: Eye movement
Trigeminal: Facial sensation, chewing
Abducens: Eye movement
Facial: Facial expression, anterior taste buds
Vestibulocochlear: Hearing
Glossopharyngeal: Posterior taste buds, swallowing
Vagus: Motor and sensory for abdominal organs
Accessory: Motor for neck muscles
Hypoglossal: Motor and sensory for tongue movement

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Description

This quiz covers essential topics related to cranial nerves, the central and peripheral nervous systems, and neuroglia. Test your knowledge on the functions and types of cranial nerves, as well as the supporting cells of the CNS. A must for students of anatomy and physiology!