Nervous System: Anatomy and Function

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Questions and Answers

What physiological distinction differentiates the nervous system's regulatory approach from that of the endocrine system?

  • The nervous system primarily influences reproductive functions, contrasting with the endocrine system's role in immune response.
  • The nervous system directly alters cellular DNA, unlike the endocrine system which modifies protein structures.
  • The nervous system responds using electrical signals for rapid communication, whereas the endocrine system uses hormones for slower, sustained effects. (correct)
  • The nervous system regulates exclusively metabolic processes, while the endocrine system affects growth and development.

How does the integrative function of the nervous system contribute to complex cognitive processes?

  • By directly stimulating muscle contractions in response to external stimuli.
  • By selectively blocking certain sensory inputs to prevent cognitive overload.
  • By converting sensory input into immediate hormonal secretions.
  • By analyzing sensory information, facilitating decision-making and enabling memory storage for future actions. (correct)

What best describes the efferent function of motor neurons?

  • Conducting nerve impulses from the central nervous system to effector organs, such as muscles or glands (correct)
  • Transmitting sensory information from receptors to the central nervous system
  • Integrating sensory input with stored memories to formulate a response
  • Regulating the chemical environment around neurons to optimize signal transmission

In the context of nervous system organization, what characterizes the enteric nervous system's unique function?

<p>It independently monitors and controls chemical changes and muscular contractions within the gastrointestinal tract. (A)</p> Signup and view all the answers

What functional attribute is exclusive to neurons compared to neuroglia?

<p>The capability to generate and propagate action potentials in response to stimuli. (D)</p> Signup and view all the answers

Considering the function of astrocytes, what critical role do they play in protecting the central nervous system?

<p>Forming the blood-brain barrier by surrounding blood capillaries, limiting the entry of harmful substances into the brain. (A)</p> Signup and view all the answers

In the context of action potential generation, what ionic event characterizes the depolarization phase?

<p>Influx of sodium ions ($Na^+$) into the cell, increasing the intracellular voltage to a positive value. (D)</p> Signup and view all the answers

How does saltatory conduction enhance the speed of nerve impulse transmission in myelinated axons?

<p>By concentrating ion channels at the nodes of Ranvier, allowing action potentials to 'jump' between these points. (B)</p> Signup and view all the answers

How do electrical synapses facilitate nerve impulse transmission as compared to chemical synapses?

<p>By physically connecting adjacent neurons through gap junctions for direct and rapid ion flow. (A)</p> Signup and view all the answers

Gamma-aminobutyric acid (GABA) is involved in what?

<p>Inhibiting neurotransmission to reduce neuronal excitability throughout the central nervous system. (D)</p> Signup and view all the answers

What structural feature characterizes the dura mater, and how does this relate to its function?

<p>It is made of tough, dense, irregular connective tissue, providing a protective outer layer for the brain and spinal cord. (A)</p> Signup and view all the answers

What is the functional significance of the cervical and lumbar enlargements of the spinal cord?

<p>They accommodate the increased number of neurons needed to innervate the upper and lower limbs, respectively. (B)</p> Signup and view all the answers

The function of the sacral plexus is to supply nerves to which regions?

<p>The buttocks, perineum, and lower limbs (D)</p> Signup and view all the answers

How do the tightly sealed capillaries and astrocytes contribute to the blood-brain barrier's function?

<p>Selectively restricting the passage of substances from the blood into the brain, protecting it from harmful compounds and pathogens. (D)</p> Signup and view all the answers

What role does the medulla oblongata play in maintaining vital bodily functions?

<p>Controlling heart rate, blood vessel diameter, and breathing rhythm through its cardiovascular and medullary rhythmicity centers. (D)</p> Signup and view all the answers

What is the role of the red nuclei in the midbrain?

<p>Coordinating movement with the cerebellum. (A)</p> Signup and view all the answers

How does the hypothalamus contribute to maintaining homeostasis within the body?

<p>Controlling the autonomic nervous system, pituitary gland, and regulating functions like body temperature, thirst, and circadian rhythms. (B)</p> Signup and view all the answers

What are the key functions of the cerebellum?

<p>Maintaining balance, posture, and coordinating complex sequences of skeletal muscle contractions. (B)</p> Signup and view all the answers

How does the somatosensory association area contribute to our understanding of the environment?

<p>By integrating and interpreting somatic sensations such as shape, texture, and object identity, and storing memories of past sensory experiences. (A)</p> Signup and view all the answers

What is the primary function of the olfactory nerve (cranial nerve I)?

<p>Mediating the sense of smell (B)</p> Signup and view all the answers

Which cranial nerve(s) has/have a primary role in controlling eye movement?

<p>The oculomotor (III), trochlear (IV), and abducens (VI) nerves (B)</p> Signup and view all the answers

What is the primary function of the vestibulocochlear nerve (cranial nerve VIII)?

<p>Regulating balance/equilibrium and hearing (D)</p> Signup and view all the answers

Which of the following cranial nerves is responsible for mediating taste sensation and controlling tongue movement?

<p>Hypoglossal nerve (XII) (B)</p> Signup and view all the answers

What is the primary distinction between the somatic and autonomic nervous systems regarding their effectors?

<p>The somatic nervous system controls skeletal muscles, while the autonomic nervous system controls cardiac muscles, smooth muscles, and glands. (C)</p> Signup and view all the answers

In the context of neural pathways, how do the somatic and autonomic nervous systems differ?

<p>The somatic system directly innervates effectors with a single neuron, whereas the autonomic system uses a two-neuron chain with a ganglion. (B)</p> Signup and view all the answers

How do the sympathetic and parasympathetic divisions of the autonomic nervous system interact to maintain homeostasis?

<p>They have antagonistic effects on target organs, with one division activating responses and the other inhibiting them. (C)</p> Signup and view all the answers

What physiological responses are typically associated with activation of the parasympathetic nervous system?

<p>Stimulation of digestion, salivation, and lacrimation (A)</p> Signup and view all the answers

What is the role of the glossopharyngeal nerve (IX) in regulating cardiovascular function?

<p>Monitoring blood pressure and blood gas levels (O2 and CO2) and relaying this information to the brainstem for regulation of breathing. (D)</p> Signup and view all the answers

How might damage to the abducens nerve (VI) manifest clinically, and what specific function would be impaired?

<p>Difficulty abducting the eye, resulting in double vision (diplopia) when looking to the affected side. (B)</p> Signup and view all the answers

Which statement accurately describes the consequences of stimulating the sympathetic nervous system?

<p>Dilation of blood vessels in organs involved in exercise or fighting off danger. (B)</p> Signup and view all the answers

How does the anatomical arrangement of white and gray matter within the spinal cord contribute to its function as a 'highway' and integration center?

<p>The white matter conducts nerve impulses from the periphery to the brain and vice versa, while the gray matter receives and integrates incoming and outgoing information. (D)</p> Signup and view all the answers

How do the unique functions of the superior and inferior colliculi in the midbrain contribute to sensory processing and behavior?

<p>The superior colliculi control reflex arcs involving eye movement, while the inferior colliculi relay auditory impulses to the thalamus. (B)</p> Signup and view all the answers

The reticular activating system (RAS)'s structure is characterized by?

<p>Small clusters of neuronal cell bodies intermingled with small bundles of white matter in the brainstem. (B)</p> Signup and view all the answers

How does the arrangement of the primary somatosensory and motor areas in the cerebral cortex reflect the body's representation, and what is the functional consequence of this organization?

<p>The body is represented proportionally, with larger cortical areas dedicated to regions with high receptor density or fine motor control, enhancing sensory discrimination and skilled movements. (C)</p> Signup and view all the answers

In a scenario where a stroke damages the Broca's area, what specific deficit would a patient likely exhibit, and what cognitive process would be most directly affected?

<p>Difficulty initiating and coordinating the complex movements needed for speech, resulting in expressive aphasia. (D)</p> Signup and view all the answers

How does the integrated function of the white and gray matter contribute to spinal cord physiology?

<p>White matter conducts nerve impulses, the gray matter receives, integrates incoming information to elicit a reflex. (D)</p> Signup and view all the answers

What is the functional consequence of damage to the long thoracic nerve?

<p>Protrusion of the scapula from the back when pushing against a wall. (A)</p> Signup and view all the answers

If a patient presents with a "claw hand" deformity following a nerve injury, which nerve is MOST likely affected, and what is the primary functional deficit?

<p>Ulnar nerve; impaired finger adduction and abduction. (B)</p> Signup and view all the answers

A patient exhibits the 'waiter's tip' position. Which nerve roots are MOST likely affected, and what is the primary movement deficit observed?

<p>C5-C6 nerve roots with impaired shoulder and upper arm function. (C)</p> Signup and view all the answers

Damage to which nerve would MOST significantly impair grip strength and fine motor control of the fingers?

<p>Ulnar nerve. (C)</p> Signup and view all the answers

What is the key distinction between the functions of the sympathetic and parasympathetic nervous systems in the context of male sexual function?

<p>The parasympathetic system controls erection, while the sympathetic system controls ejaculation. (D)</p> Signup and view all the answers

How do the five phases of the brachial plexus (roots, trunks, divisions, cords, branches) contribute sequentially to the nerve supply of the upper limb?

<p>They create a complex network that consolidates spinal nerve inputs into major functional nerves, allowing both motor and sensory signals to be distributed throughout the arm. (C)</p> Signup and view all the answers

What is the clinical significance of dermatomes in diagnosing neurological conditions?

<p>Dermatomes allow clinicians to identify the specific spinal nerve affected by observing patterns of sensory loss or pain on the skin. (D)</p> Signup and view all the answers

How can the analysis of cerebrospinal fluid (CSF) obtained through a lumbar puncture aid in diagnosing meningitis?

<p>It detects pathogens and inflammatory markers indicative of infection. (B)</p> Signup and view all the answers

How does the myelin sheath contribute to the efficiency of neuronal signaling, and what cellular components are responsible for its formation in the central and peripheral nervous systems?

<p>It increases the speed of signal transmission through saltatory conduction, formed by oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system. (B)</p> Signup and view all the answers

Which of the following BEST describes the role of the vagus nerve (cranial nerve X)?

<p>Controls autonomic functions of the heart, lungs, and digestive tract, along with sensation from the ear and throat. (D)</p> Signup and view all the answers

Which description accurately distinguishes between the somatic and autonomic components of the nervous system?

<p>The somatic nervous system controls conscious, voluntary movements, while the autonomic nervous system controls involuntary, unconscious functions. (A)</p> Signup and view all the answers

Which sequence accurately describes the progression of a sensory signal from the initial stimulus to a motor response?

<p>Dendrites receive the signal, which is passed to the soma and then transmitted along the axon to the brain/spinal cord, leading to a motor response in muscles. (D)</p> Signup and view all the answers

How does the brain ensure it receives preferential blood supply despite representing only a small percentage of the body's mass?

<p>The brain receives a disproportionately large fraction (20%) of the total blood supply to meet its high metabolic demands. (D)</p> Signup and view all the answers

How do the protective structures of the spinal cord—vertebrae, meninges, and cerebrospinal fluid (CSF)—collectively contribute to maintaining its functional integrity?

<p>The vertebrae offer structural support, the meninges provide a barrier against infection, and the CSF cushions against mechanical shock. (C)</p> Signup and view all the answers

What is the functional significance of the anatomic arrangement within the spinal cord with the epidural space surrounding the dura mater?

<p>The epidural space, containing fat and blood vessels, provides a site for administering epidural anesthesia, blocking pain signals without directly affecting the spinal cord. (B)</p> Signup and view all the answers

Which nerve is MOST likely compromised if a patient begins to develop pain and sensory loss in the medial aspect of their hand? What anatomical location is the MOST vulnerable point of compression?

<p>Ulnar nerve, compressed posterior to the medial epicondyle. (D)</p> Signup and view all the answers

A person is exposed to a stressful life-threatening situation. What is the MOST likely physiological response caused by the sympathetic nervous system?

<p>Increased heart rate, dilated pupils, and decreased digestion. (A)</p> Signup and view all the answers

Which description accurately captures the pathway and function of the sciatic nerve?

<p>Originating from the sacral plexus, it innervates the posterior thigh muscles and all muscles of the leg and foot, also providing sensation to the posterior thigh, leg, and foot. (D)</p> Signup and view all the answers

If the ventral root of a spinal nerve were severed, what would be the MOST likely functional outcome?

<p>Paralysis of the muscles supplied by the nerve. (C)</p> Signup and view all the answers

What would be the MOST likely outcome from damage to the cerebellum due to a traumatic brain injury?

<p>Impairment of motor coordination and balance. (C)</p> Signup and view all the answers

How would damage to the dorsal root ganglia of the spinal cord manifest clinically?

<p>Loss of sensation and reflex function in the corresponding dermatome. (B)</p> Signup and view all the answers

A patient arrives at the emergency department with suspected meningitis. Why is analyzing the patient's cerebrospinal fluid (CSF) crucial in the diagnostic process?

<p>To identify the presence of infectious agents and signs of inflammation. (C)</p> Signup and view all the answers

How might a tumor growing within the brain impact the normal function of surrounding neural tissue, and what is the MOST common mechanism by which this occurs?

<p>By compressing and displacing neural structures. (D)</p> Signup and view all the answers

What is a key clinical sign of median nerve palsy that involves specific hand abnormalities, and what specific motor functions are impaired?

<p>&quot;Ape hand&quot; deformity (thenar atrophy), characterized by loss of fine motor skills and thumb opposition. (A)</p> Signup and view all the answers

How does the "rest and digest" response orchestrated by the parasympathetic nervous system counteract the physiological changes induced by the sympathetic nervous system, and why is this balance crucial for overall health?

<p>By slowing heart rate, constricting pupils, and increasing digestive activity to conserve energy and promote recovery. (B)</p> Signup and view all the answers

What are the roles of afferent and efferent nerve functions?

<p>Afferent nerves carry sensory signals to the brain, while efferent nerves carry motor signals from the brain. (D)</p> Signup and view all the answers

What type of cranial nerve is the olfactory nerve, and what type of specialized information does it carry?

<p>Sensory nerve that carries information about the sense of smell. (A)</p> Signup and view all the answers

How does Multiple Sclerosis (MS) disrupt nerve function?

<p>MS causes the immune system to attack the myelin sheath, damaging or destroying it, leading to slower or disrupted nerve signals. (A)</p> Signup and view all the answers

Which cranial nerve innervates the lateral rectus muscle of the eye, and what specific eye movement does it control?

<p>Abducens nerve (VI), controlling outward (abduction) eye movement. (B)</p> Signup and view all the answers

What is the physiological basis for 'Saturday night palsy,' and what nerve is typically affected?

<p>Compression of the radial nerve in the upper arm due to prolonged pressure. (C)</p> Signup and view all the answers

Which cranial nerve is responsible for controlling tongue movements that are critical for speech and swallowing?

<p>Hypoglossal nerve (XII). (B)</p> Signup and view all the answers

What is the underlying cause of wrist drop, and how does this condition manifest in terms of motor function?

<p>Damage to the radial nerve, resulting in an inability to extend the wrist and fingers. (D)</p> Signup and view all the answers

Erb's Palsy primarily affects which nerve roots, and what are the MOST common causes?

<p>C5-C6 nerve roots, caused by excessive stretching of the neck during a difficult birth. (A)</p> Signup and view all the answers

After a traumatic accident involving a deep laceration, a hand surgeon observes that a patient has lost sensation on the anterior two-thirds of their tongue. Which nerve has MOST likely been severed during the incident?

<p>Facial nerve. (A)</p> Signup and view all the answers

Following a motorcycle accident, a patient displays paralysis of muscles of facial expression on the left side of their face along with a loss of taste sensation on the anterior two-thirds of the tongue. Which nerve have they likely damaged?

<p>Left facial nerve. (D)</p> Signup and view all the answers

One role of the myelin sheath is to protect the axon. What other functions does the myelin sheath have that improve neuron efficiency?

<p>The myelin sheath increases signal speed and reduces energy use, enabling signals to travel faster. (D)</p> Signup and view all the answers

Which of the following accurately describes the anatomical arrangement of neurons within the autonomic nervous system (ANS)?

<p>Two neurons synapse in a ganglion outside the CNS, which is a distinguishing feature of the ANS. (C)</p> Signup and view all the answers

How does norepinephrine (NE) act differently in the sympathetic nervous system compared to acetylcholine (ACh) in the parasympathetic nervous system?

<p>Norepinephrine can elicit both stimulatory and inhibitory effects depending on the receptor type on the target organ, unlike acetylcholine, which primarily has a consistent effect (e.g. decrease heart rate). (C)</p> Signup and view all the answers

In a scenario where a drug selectively blocks muscarinic receptors, what physiological changes would MOST likely be observed?

<p>Increased heart rate, decreased salivation, and bronchodilation. (B)</p> Signup and view all the answers

Which statement BEST elucidates the functional distinction between alpha and beta adrenergic receptors in the sympathetic nervous system (SNS)?

<p>Alpha receptors primarily induce smooth muscle contraction, leading to vasoconstriction, whereas beta receptors generally promote smooth muscle relaxation, causing vasodilation. (B)</p> Signup and view all the answers

How does the parasympathetic nervous system influence digestive processes during the 'rest and digest' response?

<p>By increasing intestinal motility, opening sphincters, and promoting secretion to enhance digestion. (C)</p> Signup and view all the answers

Which of the following is a key difference in the influence of the autonomic nervous system on the bladder?

<p>Sympathetic stimulation relaxes the bladder wall and closes the sphincter, whereas parasympathetic activation contracts the bladder wall and opens the sphincter. (A)</p> Signup and view all the answers

Which of the following describes the mechanism by which sympathetic stimulation affects the heart?

<p>It increases heart rate and contractility by activating beta-adrenergic receptors. (B)</p> Signup and view all the answers

What is the physiological basis for the differing effects of the sympathetic and parasympathetic nervous systems on bronchial smooth muscle?

<p>The sympathetic nervous system causes bronchodilation via beta-adrenergic receptors, while the parasympathetic causes bronchoconstriction via muscarinic receptors. (B)</p> Signup and view all the answers

How does the sympathetic nervous system mediate its effects on the skin, specifically regarding pilomotor smooth muscles and sweat glands?

<p>It causes pilomotor smooth muscle contraction and increases sweating. (B)</p> Signup and view all the answers

Which statement adequately describes the effect of the sympathetic nervous system on metabolic functions, specifically in the liver?

<p>It promotes gluconeogenesis and glycogenolysis, leading to increased blood glucose levels. (B)</p> Signup and view all the answers

What role does the adrenal medulla play in the sympathetic nervous system's response to stress?

<p>It releases both epinephrine and norepinephrine into the bloodstream, prolonging and amplifying the sympathetic response. (C)</p> Signup and view all the answers

How does the autonomic nervous system (ANS) influence male genitalia, and what is the specific role of the sympathetic division in this context?

<p>The sympathetic division controls ejaculation, while the parasympathetic facilitates vasodilation, leading to erection. (C)</p> Signup and view all the answers

How do changes in pupillary diameter reflect the differential actions of the sympathetic and parasympathetic nervous systems?

<p>Sympathetic activation dilates the pupils, enhancing far vision, while parasympathetic activation constricts the pupils, improving near vision. (D)</p> Signup and view all the answers

Why is understanding the specific anatomical arrangement of autonomic ganglia crucial in predicting the effects of certain nerve injuries or pharmacological interventions?

<p>The location of autonomic ganglia dictates whether the sympathetic or parasympathetic system is affected, influencing the resulting symptoms. (B)</p> Signup and view all the answers

How does the effect of sympathetic stimulation on renal vascular smooth muscle contribute to systemic blood pressure regulation?

<p>Sympathetic stimulation causes vasoconstriction, decreasing blood flow to the kidneys and increasing blood pressure. (D)</p> Signup and view all the answers

Which of the following accurately describes the role of nicotinic receptors in autonomic ganglia?

<p>They are activated by acetylcholine, leading to excitation of postganglionic neurons. (C)</p> Signup and view all the answers

In what way does the 'fight or flight' response, mediated by the sympathetic nervous system, affect salivary gland secretions?

<p>It leads to the production of thick, viscous saliva, reducing digestive efficiency. (B)</p> Signup and view all the answers

How does the sympathetic nervous system influence lipolysis in adipose cells to support the body's energy needs during stress?

<p>It stimulates lipolysis, breaking down triglycerides into fatty acids and glycerol to provide energy. (D)</p> Signup and view all the answers

Which description correctly identifies how adrenergic receptors contribute to the regulation of cardiac function by the sympathetic nervous system?

<p>Activation of beta-1 adrenergic receptors increases heart rate and contractility. (A)</p> Signup and view all the answers

How does activation of dopamine receptors (D1) on renal vascular smooth muscle contribute to blood pressure regulation?

<p>It causes vasodilation, decreasing blood pressure. (B)</p> Signup and view all the answers

What is the key distinction in the sympathetic vs parasympathetic origin of the parts of the spine?

<p>The parasympathetic nervous system originates in the cranial (cervical) and sacral regions, whilst the sympathetic nervous system originates in the thoracic and lumbar regions. (A)</p> Signup and view all the answers

What distinguishes the SOMATIC and AUTONOMIC nervous system anatomically?

<p>The autonomic nervous system uses a two-neuron chain, and the somatic nervous system uses a one-neuron setup. (B)</p> Signup and view all the answers

Where is the neurotransmitter at the effector of the somatic nervous system produced?

<p>Central Nervous System (C)</p> Signup and view all the answers

Which describes a function that is exclusive to the autonomic nervous system compared to the somatic nervous system?

<p>Involuntary movement such as heartbeat (B)</p> Signup and view all the answers

What is the main difference between visceral stimuli and somatic stimuli?

<p>Visceral stimuli is from stimuli inside the body, and somatic stimuli is from stimuli outside the body (C)</p> Signup and view all the answers

What accurately describes the efferent division?

<p>Motor neurons (A)</p> Signup and view all the answers

What is the name of the neurotransmitter at the effector for the parasympathetic nervous system?

<p>Acetylcholine (Ach) (B)</p> Signup and view all the answers

What is NOT a neurotransmitter released in the sympathetic nervous system?

<p>ACh Acetylcholine (C)</p> Signup and view all the answers

The sympathetic nervous system originates in which part of the spine?

<p>Thoracic (C)</p> Signup and view all the answers

Which type of system stimulates renal vascular smooth muscle?

<p>Sympathetic (D)</p> Signup and view all the answers

An increase in what causes contraction and secretion? (See the Receptor/Location/ G Protein table.)

<p>IP3, DAG (A)</p> Signup and view all the answers

The heart has positive Inotropic and Chronotropic. What are inotropic and chronotropic?

<p>↑ heart rate, ↑ force (C)</p> Signup and view all the answers

Which of the options applies to the digestive tract in the parasympathetic NS?

<p>All of the above (D)</p> Signup and view all the answers

Which of the options applies to the pupils during dilation in the eye?

<p>Far Vision (C)</p> Signup and view all the answers

What is the effect of the parasympathetic nervous system on the male genitalia?

<p>Erection (C)</p> Signup and view all the answers

What is a function of the pilomotor smooth muscles?

<p>Contraction (C)</p> Signup and view all the answers

What is the function of skeletal contraction? (See the Sympathetic Nervous System and Parasympathetic Nervous System table.)

<p>Skeletal muscles (B)</p> Signup and view all the answers

Flashcards

Sensory Function

Detects internal and external stimuli; uses sensory or afferent neurons.

Integrative Function

Analyzes information to decide on a response; uses interneurons.

Motor Function

Elicits a motor response via motor or efferent neurons.

Central Nervous System (CNS)

Brain and spinal cord

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Peripheral Nervous System (PNS)

Cranial nerves, spinal nerves, ganglia, and sensory receptors

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Somatic Nervous System

Sensory from somatic receptors and motor to skeletal muscles (voluntary)

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Autonomic Nervous System

Sensory from visceral receptors and motor to smooth/cardiac muscle (involuntary)

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Enteric Nervous System

Sensory neurons monitor chemical changes/stretching; motor neurons govern GI tract (involuntary)

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Neurons

Respond to stimuli; causes action potentials

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Dendrites

Receives stimuli

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Soma

Synthesis of molecules for neuron function

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Axon

Conducts nerve impulses to another neuron

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Synapse

Spaces where neurons communicate

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Afferent Neurons

Carry sensory info to the CNS

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Efferent Neurons

Convey action potentials away from the CNS to the effectors

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Interneurons

Located in the CNS between sensory and motor neurons; integrate incoming info

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Neuroglia

Supports, nourishes, and protects neurons and maintains interstitial fluid

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Astrocytes

Support neurons and form the blood-brain barrier

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Oligodendrocytes

Form and maintain the myelin sheath in the CNS

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Microglia

Phagocytose cellular debris and microbes

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Ependymal Cells

Lines brain ventricles and spinal cord; assists in CSF circulation

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Schwann Cells

Form myelin sheath around axons in the PNS

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Satellite Cells

Support ganglia; regulate material exchange

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Membrane Potential

Difference in electrical charge inside vs. outside the plasma membrane

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Resting Membrane Potential

Outside is positive (+), inside is negative (-)

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Depolarization

Na+ channels open, Na+ influx, cell becomes positively charged

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Repolarization

K+ channels open, K+ exits, cell becomes negatively charged again

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Electrical Synapse

Nerve impulses conducted directly through gap junctions

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Chemical Synapse

Nerve impulse causes neurotransmitter release into the synaptic cleft

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Acetylcholine

Released by PNS and some CNS neurons; excitatory or inhibitory

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Glutamate & Aspartate

Excitatory neurotransmitters in the CNS

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Gamma Aminobutyric Acid (GABA)

Inhibitory neurotransmitter

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Norepinephrine

Arousal and mood regulation

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Dopamine

Emotional responses and pleasure

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Serotonin

Sensory perception, mood, appetite and onset of sleep

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Endorphins

Body's natural painkillers; improved memory and learning

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Meninges

Three connective tissue coverings around the spinal cord and brain

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Dura Mater

Tough, dense outer layer of the meninges

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Arachnoid Mater

Middle layer of the meninges; collagen & elastic fibers, subarachnoid space

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Pia Mater

Deepest layer of the meninges; highly vascularized

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Sympathetic Nervous System

A system preparing the body for stressful situations by increasing alertness and energy. Heart rate and breathing increase, and digestion slows.

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Parasympathetic Nervous System

A system that helps the body relax, recover, and restore energy after stress. Heart rate slows, breathing slows, and digestion resumes.

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Brachial Plexus

A network of nerves in the shoulder region that controls movement and sensation in the shoulder, arm, and hand, originating from spinal nerves C5 to T1.

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Dermatome

An area of skin supplied by sensory fibers from a single spinal nerve root, relaying touch, pain, and temperature.

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Myelin Sheath

A fatty, insulating layer around an axon that increases signal speed, protects the axon, and reduces energy use.

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Multiple Sclerosis (MS)

A disease where the immune system attacks the myelin sheath, damaging or destroying it, leading to disrupted nerve signals.

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Spinal cord

Transmits signals between the brain and the rest of the body.

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Long Thoracic Nerve

Innervates the serratus anterior muscle to stabilize scapula, allowing arm elevation and forward pushing.

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Tachycardia

Fast heart rate, above 100 bpm, caused by stress, exercise, fever, or heart conditions.

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Bradycardia

Slow heart rate, below 60 bpm, resulting from aging, medications, or medical conditions.

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Sacral Plexus

A network of nerves in the posterior pelvis for motor and sensory innervation to the lower limb, pelvis, and perineum.

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Anococcygeal nerve

Sensory innervation to the skin over the coccyx, perianal region, and anus; aids in continence.

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Meningitis

inflammation of the protective brain and spinal cord membranes.

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Cerebrum

The largest part of the brain

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Hypothalamus

Responsible for temperature regulation

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Autonomic Nervous System (ANS)

The division of the nervous system that controls involuntary actions, such as heart rate, digestion, and breathing.

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Afferent Division

Division of PNS that carries sensory information to the CNS.

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Efferent Division

Division of PNS that carries motor commands from the CNS to effectors.

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Ganglion

Neuron cell bodies located outside the CNS.

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Autonomic Nervous System (ANS)

Controls involuntary actions of smooth muscle, cardiac muscle, and glands.

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Enteric Nervous System (ENS)

Specialized nervous system that regulates the gastrointestinal tract.

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Sympathetic - Eye

Dilation of pupils for far vision.

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Parasympathetic - Eye

Constriction of pupils for near vision.

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Sympathetic - Heart

Increasing heart rate and force of contraction.

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Parasympathetic - Heart

Decreasing heart rate and force of contraction

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Sympathetic - Bronchioles

Dilation of bronchial airways.

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Parasympathetic - Bronchioles

Constriction of bronchial airways.

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Parasympathetic - Intestines

Stimulation increases motility and secretions.

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Muscarinic receptors

Receptors that bind to Acetylcholine.

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Adrenergic Receptor (Alpha and Beta)

Receptors that are activated by norepinephrine and epinephrine.

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Acetylcholine (ACh)

A neurotransmitter released by preganglionic neurons in both sympathetic and parasympathetic systems.

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Norepinephrine (NE)

A neurotransmitter released by most postganglionic sympathetic neurons.

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Study Notes

  • Autonomic Nervous System controls involuntary functions
  • Divided into Central Nervous System (CNS) and Peripheral Nervous System (PNS).

Central Nervous System (CNS)

  • Comprises the brain and spinal cord.
  • Receives input from the periphery and sends outputs back.

Peripheral Nervous System (PNS)

  • Contains the Afferent and Efferent Divisions
  • PNS divided into somatic, autonomic, and enteric nervous systems.

Afferent Division

  • Transmits sensory stimuli from the body to the CNS
  • Somatic and Visceral Stimuli

Efferent Division

  • Carries signals from the CNS to effector organs.

Somatic Nervous System (SNS)

  • Controls voluntary movement.
  • Single neuron setup from CNS to effector organs.
  • Utilizes motor neurons to stimulate skeletal muscles.
  • Neurotransmitter at effector is Acetylcholine (ACh), which is stimulatory

Autonomic Nervous System (ANS)

  • Regulates unconscious processes.
  • Controls smooth muscle, cardiac muscle, some endocrine and exocrine glands.
  • Consists of two-neuron chain between CNS and effector organs
  • Ganglion contains collection of neuron cell bodies located outside the CNS, an exclusive feature.
  • Divided into sympathetic, parasympathetic, and enteric branches.

Sympathetic Nervous System

  • Emerges from the thoracic and lumbar regions of the spinal cord.
  • The neurotransmitter used is acetylcholine (ACh) from lightly myelinated preganglionic axons
  • Postganglionic axons nonmyelinated, use norepinephrine (NE).
  • Adrenal medulla releases epinephrine and NE directly into the bloodstream.
  • Controls bodily functions like pupil dilation, bronchodilation, and increased heart rate and force.
  • Leads to ejaculation of male genitalia, uterus relaxation, thick, viscid secretion in salivary glands.
  • Causes pilimotor smooth muscles and sweat glands to contract or sweat during exercise.
  • Causes gluconeogenesis, glycogenolysis, lipolysis, and renin release in the liver, fat cells, and kidneys.
  • Origin is spine Thoracic and Lumbar
  • Receptor is A, B, D
  • Neurotransmitter is catecholamines

Parasympathetic Nervous System

  • Arises from the cranial and sacral regions of the spinal cord.
  • Uses acetylcholine (ACh) as the neurotransmitter.
  • Encourages "rest and digest" activities.
  • Controls bodily functions like pupil constriction, bronchoconstriction, and decreased heart rate and force.
  • Leads to erection in male genitalia, uterus contraction, copious, watery secretion in salivary glands
  • Origin is spine Cranial (Cervical) and Sacral
  • Receptor is N, M
  • Neurotransmitter is acetylcholine

Enteric Nervous System

  • Manages digestive organs independently.
  • Can be influenced by the sympathetic and parasympathetic systems.
  • Functions in digestive organs only

Somatic vs Autonomic Nervous System

Somatic Nervous System

  • Anatomy involves 1 Neuron Setup
  • Functional is voluntary movement
  • Contraction of the Skeletal Muscle

Autonomic Nervous System

  • Anatomy involves 2 Neuron Setup
  • Functional is Involuntary Movement
  • Heartbeat, Contraction of the blood vessels, sweat glands

Sympathetic vs Parasympathetic NS

Eye

  • Sympathetic dilates pupils
  • Parasympathetic constricts pupils
  • Sympathetic causes far vision
  • Parasympathetic causes near vision function
  • The bronchial smooth muscles bronchodilate under sympathetic control and bronchoconstriction when parasympathetic

Heart

  • Sympathetic increases inotropic and chronotropic
  • Parasympathetic decreases inotropic and chronotropic

Gastrointestinal Tract

  • Sympathetic: Sphincters Close, intestinal wall muscles decrease motility, and a decrease in secretions.
  • Parasympathetic: Sphincters Open, intestinal wall muscles increase motility, and an in increase in secretions.

Bladder

  • Sympathetic: Sphincter closes, and wall muscles relax.
  • Parasympathetic: Sphincter opens, and Wall muscles contract.

Autonomic Receptors and Functions

  • Alpha1 (α₁) receptors located in effector tissues such as smooth muscle and glands, use Gq protein, increase IP3 and DAG, and result in increased Ca2+, causing contraction and secretion
  • Alpha2 (α₂) receptors found in nerve endings and some smooth muscle, use Gi protein, decrease cAMP, and decrease transmitter release or cause contraction.
  • Beta1 (β₁) receptors in cardiac muscle and the juxtaglomerular apparatus, use Gs protein, increase cAMP, and increase heart rate, force and renin release.
  • Beta2 (β₂) receptors located in smooth muscle, liver, and heart, use Gs protein, increase cAMP, relax smooth muscle, increase glycogenolysis, and increase heart rate and force.
  • Beta3 (β₃) receptors in adipose cells, use Gs protein, increase cAMP, and increase lipolysis.
  • Dopamine (D₁) receptors found in smooth muscle, use Gs protein, increase cAMP, and relax renal vascular smooth muscle.

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