Neural Organization Quiz

The SNS causes the pupils of the eye to dilate, decreases peristalsis (muscle contractions) in the stomach and intestines to slow down digestion, and increases sweat gland secretion.

The dorsal root ganglion houses the cell bodies of sensory neurons, which receive sensory information from the body and transmit it to the spinal cord.

Somatic pain originates from the skin, muscles, bones, and joints, and tends to be well-localized. Examples include a paper cut or a sprained ankle. Visceral pain, on the other hand, arises from internal organs and is often poorly localized and described as dull or aching. Examples include pain from a gallstone, appendicitis, or a heart attack.

<p>Exteroceptors receive stimuli from the external environment, like the touch of a hand on a table. Interoceptors sense stimuli from within the body, like the fullness of the stomach. Proprioceptors detect the position and movement of the body, like the stretch of a muscle.</p> Signup and view all the answers

<p>Referred pain occurs when pain from an internal organ is perceived as originating from a different location on the body surface. This happens because sensory neurons from both the organ and the skin converge on the same second-order neurons in the spinal cord. The brain, unable to distinguish the origin, interprets the signal as coming from the skin region, resulting in referred pain.</p> Signup and view all the answers

<p>Sound waves travel through the outer ear and cause vibrations in the eardrum. These vibrations are transmitted through the middle ear bones (malleus, incus, stapes) to the oval window of the cochlea. The pressure waves in the cochlea cause fluid movement, which bends hair cells in the organ of Corti. This bending triggers electrical signals that travel to the auditory nerve and ultimately the brain.</p> Signup and view all the answers

<p>Fast pain, also known as sharp or pricking pain, is transmitted rapidly by myelinated A-delta nerve fibers. It is well-localized and short-lived, caused by mechanical or thermal stimuli. Slow pain, on the other hand, is transmitted more slowly by unmyelinated C-fibers. It is dull, aching, and often poorly localized, and can last for a long time, caused by chemical or inflammatory stimuli.</p> Signup and view all the answers

<p>Three pain disorders are: 1) <strong>Fibromyalgia</strong>: a chronic widespread musculoskeletal pain accompanied by fatigue, sleep, and cognitive issues, thought to be caused by amplified pain signals in the central nervous system. 2) <strong>Migraines</strong>: recurring, debilitating headaches with severe pain, often accompanied by nausea, vomiting, and light sensitivity, believed to be triggered by abnormal brain activity and altered blood flow. 3) <strong>Neuropathic pain</strong>: caused by damage to peripheral nerves, often leading to burning, tingling, and shooting pain, resulting from nerve misfiring and altered signal transmission. These disorders become chronic due to persistent pain signals, altered neural pathways, and maladaptive pain processing mechanisms.</p> Signup and view all the answers

<p>The cerebellum plays a crucial role in coordinating smooth, precise movements, maintaining balance, and learning new motor skills. Damage to the cerebellum can lead to tremors, clumsiness, ataxia (loss of coordination), difficulties with balance, and slurred speech.</p> Signup and view all the answers

<p>The direct pathway, also known as the pyramidal pathway, originates in the motor cortex and travels directly to the spinal cord, allowing for voluntary movement and fine motor control. The indirect pathway, or extrapyramidal pathway, involves multiple brain regions like the basal ganglia and brainstem, and is responsible for subconscious and automatic movements, posture, and muscle tone.</p> Signup and view all the answers

<p>The gate control theory states that pain signals are modulated at the spinal cord level. There is a &quot;gate&quot; that can be opened or closed, allowing more or less pain signals to reach the brain. Rubbing a painful area activates large-diameter sensory fibers, which inhibit the transmission of pain signals through the gate, reducing pain perception. Similarly, using electrical stimulation can activate these large fibers, effectively &quot;closing&quot; the gate and diminishing pain. This theory provides a framework for understanding how sensory input, cognitive factors, and emotional states can influence pain perception and modulate pain signals.</p> Signup and view all the answers

<p>The premotor area plays a critical role in planning and organizing complex motor sequences, such as playing the piano or typing on a keyboard. It receives input from sensory areas and the prefrontal cortex, allowing it to select appropriate movements based on context. For example, the premotor area would be active when planning the sequence of keystrokes to type a sentence.</p> Signup and view all the answers

<p>The vestibular organs, located in the inner ear, detect changes in head position and movement. Otoliths, small calcium carbonate crystals, are embedded in the gelatinous substance of the utricle and saccule, which sense linear acceleration and gravity. When the head moves, the otoliths shift, stimulating hair cells that send signals to the brain about head position and movement. This information, combined with input from other sensory systems, helps maintain balance and spatial orientation.</p> Signup and view all the answers

<p>The resting membrane potential is established by the differential distribution of ions across the neuronal membrane, primarily K+ and Na+. The membrane is selectively permeable to K+, which tends to leak out of the cell due to its concentration gradient. This outward movement of K+ creates a negative charge inside the cell. The Na+/K+ pump actively transports 3 Na+ ions out for every 2 K+ ions in, further contributing to the negative intracellular charge. The equilibrium potential for potassium (EK) is typically close to the resting membrane potential, indicating that K+ permeability is dominant at rest. This potential is also influenced by the permeability of other ions like sodium, although to a lesser extent.</p> Signup and view all the answers

<p>Myelin acts as an insulating sheath around the axon, increasing the speed of action potential propagation by reducing capacitance and minimizing ion leakage across the membrane. This allows the action potential to jump between the nodes of Ranvier, where the myelin sheath is interrupted, a process called saltatory conduction. Unmyelinated axons lack this insulation, resulting in slower conduction velocities as the signal must continuously regenerate along the entire length of the axon.</p> Signup and view all the answers

<p>The Nernst equation calculates the equilibrium potential for a single ion, taking into account its concentration gradient and charge. It helps predict the membrane potential if the membrane were only permeable to that specific ion. The Goldman equation considers the permeability of multiple ions and calculates the membrane potential based on the relative permeability of each ion. It provides a more accurate representation of the membrane potential in a real-world scenario where multiple ions contribute to the membrane potential.</p> Signup and view all the answers

<p>Multipolar neurons, with multiple dendrites and a single axon, are commonly found in the central nervous system and serve diverse functions like integrating sensory information and transmitting motor commands. Bipolar neurons, featuring one dendrite and one axon, are often found in sensory systems like the retina and olfactory epithelium, relaying specific sensory input. Unipolar neurons, with a single process that branches into dendrites and an axon, are typically involved in transmitting sensory information from the periphery to the central nervous system.</p> Signup and view all the answers

<p>The cerebrum, the largest part of the brain, is responsible for higher-level cognitive functions including language, memory, and reasoning. The brainstem, connecting the cerebrum and spinal cord, controls vital functions such as breathing, heart rate, and blood pressure. The cerebellum, located at the back of the brain, coordinates movement, balance, and posture. These three structures work interdependently to process sensory information, generate motor commands, and regulate physiological processes, ensuring a smooth and coordinated functioning of the nervous system.</p> Signup and view all the answers

<p>The blood-brain barrier is a protective system formed by the tight junctions between endothelial cells lining brain capillaries. It restricts the passage of many substances from the bloodstream into the brain, protecting the delicate neural tissue from potentially harmful substances. This barrier is highly selective, allowing essential nutrients and gases to pass while blocking pathogens, toxins, and some drugs. Specialized transport proteins are involved in moving specific molecules across the barrier.</p> Signup and view all the answers

<p>An increase in extracellular potassium to 150mM would significantly depolarize the cell, driving the membrane potential closer to zero. This is because the concentration gradient for potassium would be greatly reduced, leading to an influx of potassium ions into the cell. This drastic change in membrane potential could lead to overstimulation of the cell and potentially, even cell death.</p> Signup and view all the answers

<p>The three meninges form protective layers around the brain and spinal cord. The dura mater, the outermost layer, is a tough, fibrous membrane that provides overall structural support. The arachnoid mater, a delicate middle layer, is filled with cerebrospinal fluid and serves as a cushion. The pia mater, the innermost layer, is a thin membrane that closely adheres to the brain and spinal cord, providing vascular support. These layers work together to protect the delicate neural tissue from injury, maintain intracranial pressure, and provide a protective barrier against infection.</p> Signup and view all the answers

<p>A 10-fold increase in sodium permeability would lead to a significant influx of sodium ions into the cell, resulting in depolarization. The membrane potential would shift from -70mV to a more positive value Closer to the sodium equilibrium potential, leading to depolarization.</p> Signup and view all the answers

<p>Repolarization is the process of restoring the membrane potential to its resting negative value after a depolarization event. It is primarily driven by the efflux of potassium ions out of the cell, through voltage-gated potassium channels. The sodium-potassium pump actively transports 3 sodium ions out of the cell and 2 potassium ions into the cell, restoring the ion gradients and contributing to the re-establishment of the resting membrane potential.</p> Signup and view all the answers

<p>CSF plays a crucial role in supporting the central nervous system. It acts as a protective cushion, absorbing shock and protecting the brain and spinal cord from injury. CSF also helps regulate intracranial pressure and provides a medium for transporting nutrients, hormones, and waste products within the CNS. Its continuous circulation helps maintain a stable chemical environment, critical for optimal neuronal function.</p> Signup and view all the answers

<p>The frequency of neuronal firing is directly related to the likelihood of an action potential being triggered. High-frequency firing leads to a faster accumulation of excitatory neurotransmitters at the synapse, increasing the probability of reaching the threshold for action potential generation. Conversely, low-frequency firing reduces the likelihood of reaching the threshold, making it less likely that an action potential will be generated.</p> Signup and view all the answers

<p>The autonomic nervous system is responsible for regulating involuntary bodily functions, such as heart rate, respiration, digestion, and blood pressure. The sympathetic nervous system, often referred to as the 'fight-or-flight' system, prepares the body for stressful situations by increasing heart rate, dilating pupils, and diverting blood flow to muscles. The parasympathetic nervous system, known as the 'rest-and-digest' system, promotes relaxation and energy conservation, slowing heart rate, constricting pupils, and stimulating digestion.</p> Signup and view all the answers

<p>The paravertebral ganglia are a chain of interconnected ganglia located along the vertebral column on either side of the spinal cord. They serve as relay stations for sympathetic preganglionic fibers, allowing for the distribution of sympathetic signals to various target organs. Not all sympathetic preganglionic fibers synapse in the paravertebral ganglia. Some fibers bypass these ganglia and synapse with chromaffin cells in the adrenal medulla.</p> Signup and view all the answers

<p>Norepinephrine can trigger both vasoconstriction and vasodilation depending on the type of adrenergic receptor present on the vascular smooth muscle cells. Binding to alpha-1 receptors leads to vasoconstriction, while binding to beta-2 receptors causes vasodilation. The specific response is determined by the receptor subtype present on the target vessel.</p> Signup and view all the answers

<p>Increased parasympathetic activity slows heart rate, promotes vasodilation in specific regions, constricts airways, and stimulates digestion. These effects support a state of relaxation and energy conservation. Slowing heart rate reduces energy expenditure, vasodilation promotes blood flow to digestive organs, constricted airways reduce airflow and conserve energy, and stimulated digestion allows for efficient nutrient absorption and processing.</p> Signup and view all the answers

The route motor signals travel from the cerebral cortex to the spinal cord.

The five parts of a reflex arc are receptor, sensory neuron, integration center, motor neuron, and effector.

Somatic pain originates from body surface/skin, while visceral pain comes from internal organs.

Fast pain is sharp and localizable; slow pain is dull, aching, and diffuse.

To maintain balance by activating opposite limb during withdrawal from a painful stimulus.

Contains neuronal cell bodies, dendrites, and synapses involved in processing signals.

Composed of myelinated axons that transmit signals between different parts of the nervous system.

Part of the spinal cord that contains sensory neurons receiving input from sensory receptors.

Contains motor neurons that send signals to skeletal muscles, controlling movement.

Specialized cells that respond to specific stimuli like touch, taste, and sound.

Exteroceptors detect external stimuli; interoceptors monitor internal conditions like hunger or pain.

Involved in coordinating movement and regulating voluntary motor control.

Coordinates balance, posture, and fine motor control for smooth movements.

The electrical potential difference across a cell membrane.

An action potential is triggered by a net change in membrane voltage reaching a threshold.

Excitatory Post-Synaptic Potentials, which increase the likelihood of an action potential.

Inhibitory Post-Synaptic Potentials, which decrease the likelihood of an action potential.

Repolarization occurs due to the efflux of K+ ions following depolarization.

Fibers that originate in the CNS and connect to ganglia in the autonomic nervous system.

Receptors that respond to the neurotransmitter acetylcholine.

Sympathetic prepares the body for stress; parasympathetic promotes rest and digest.

The three basic divisions are the forebrain, midbrain, and hindbrain, each serving different functions.

The cerebral cortex is the outer layer of the brain responsible for higher functions like perception, memory, and reasoning.

A selective barrier that protects the brain from harmful substances while allowing necessary molecules to pass.

Astrocytes are star-shaped glial cells that support neurons, regulate blood flow, and maintain the blood-brain barrier.

The Nernst equation calculates the equilibrium potential for a specific ion, helping to determine the resting membrane potential.

Components like dendrites, axon hillocks, and axon terminals play specific roles in transmitting signals in neurons.

The three protective membranes surrounding the brain and spinal cord are the dura mater, arachnoid mater, and pia mater.