A&P II- Ch. 14: Integration of Nervous System

Describe the process of sensation in the nervous system.

initial process initiated by stimuli acting on sensory receptors, leading to the feeling that something is occurring.

Explain the difference between sensation and perception.

Sensation refers to the initial detection of stimuli by sensory receptors, while perception is the conscious interpretation of these sensory impulses by the brain.

Define projection in the context of sensory processing.

the process by which the brain localizes the exact site of sensation on or within the body.

How does adaptation affect sensory response over time?

response leads to a decreased sensitivity and response to a continued, constant stimulus over time.

What are the two main sub-categories of general senses?

1. somatic senses: includes touch, temperature, proprioception, pain, pressure, and vibration 2. visceral senses, primarily involve pain and pressure from internal organs.

List the special senses and their corresponding functions.

sight (vision) hearing (audition) balance (equilibrium) smell (olfaction) taste (gustation)

Do general senses have a widespread distribution in the body?

Yes, general senses are distributed across the entire body.

Explain the role of visceral senses in sensory reception.

primarily detect pain and pressure originating from internal organs, contributing to the body's awareness of its internal state.

How does the brain process sensory information from the environment?

through a comprehensive review of sensory reception, cerebral cortical processing, and integration of various sensory modalities.

What is the significance of sensory receptors in the nervous system?

crucial for detecting stimuli from the internal and external environment, allowing the brain to receive and interpret information.

Describe the categorization of sensory receptors.

categorized by the type of stimulus they detect(mechanoreceptors, chemoreceptors, thermoreceptors, photoreceptors, and nociceptors) OR by their anatomical location, including cutaneous, proprioceptive, and visceroceptive.

Explain the structure and function of Free Nerve Endings.

scattered throughout most of the body, skin, and viscera. They consist of branching, unencapsulated axons that detect pain, temperature, itch, tickle, joint movement, and proprioception.

Define Merkel (Tactile) Disks and their function.

located in the basal layers of the epidermis and consist of flattened nerve expansions associated with Merkel cells. They detect light touch and superficial pressure.

How do Hair Follicle Receptors function?

they are wrapped around hair follicles and consist of nerve endings that detect light touch and slight bending of hair, with overlapping fields.

Describe the location and function of Meissner Corpuscles.

found in the dermal papillae of the fingertips and tongue. They are encapsulated in Schwann cells and are responsible for two-point discrimination and detecting texture.

Explain the role of Ruffini End Organs.

located in the dermis, primarily of the fingers. They have branching terminal knobs in a connective tissue capsule and detect continuous touch, deep pressure, and skin stretch.

What is the structure and function of Pacinian Corpuscles?

located in the deep dermis and hypodermis, near joints. They have an onion-shaped layered capsule with a single nerve fiber and detect deep cutaneous pressure, vibration, and joint proprioception.

Describe the function of Muscle Spindles.

found in skeletal muscle tissue and consist of 3–10 striated muscle fibers enclosed in a capsule. They detect muscle length/stretch and control muscle tone and stretch reflexes.

Explain the role of Golgi Tendon Organs.

associated with tendons and consist of encapsulated nerve endings wrapped around tendon fibers. They detect tendon tension/stretch and regulate muscle contraction strength.

Define receptor potential in the context of sensory signal transduction.

a local graded potential induced when a stimulus acts on a sensory receptor.

How are action potentials generated in sensory axons?

when the graded potential reaches a threshold, triggering the action potentials that are propagated toward the Central Nervous System (CNS).

Explain the concept of adaptation/accommodation in sensory receptors.

occurs when continuous or repetitive stimulation leads to a decrease in the receptor's firing rate, resulting in a lesser perceived intensity of the stimulus over time.

Describe the primary receptors function.

have the sensory stimulus directly acting on a specialized neuron, generating a receptor potential that fires action potentials along the same neuron's axon to the CNS.

Describe the secondary receptors function.

involve a distinct specialized receptor cell that triggers neurotransmitter release, depolarizing an adjacent sensory neuron.

Explain the role of the cerebral cortex in sensory processing.

cortex processes sensory input through specialized primary regions and integrates them via adjacent association areas, allowing for the interpretation and analysis of sensory information.

Define the primary somatic sensory cortex and its function.

cortex located on the postcentral gyrus and processes general sensations such as pain, pressure, and temperature, displaying topographic mapping known as the sensory homunculus.

How does the taste area of the cerebral cortex function?

cortex located at the inferior end of the postcentral gyrus (insula) and is responsible for processing taste sensations.

Identify the location and function of the olfactory cortex.

cortex is located on the inferior surface of the frontal lobe and is responsible for processing smell sensations.

Describe the primary auditory cortex and its location.

cortex is located in the superior temporal lobe and is responsible for processing auditory information.

Explain the function of the visual cortex.

cortex is located in the occipital lobe and is responsible for processing visual information.

What is the role of association areas in the cerebral cortex?

areas are located adjacent to primary sensory areas and are involved in comparing sensory signals with past experiences, analyzing, and interpreting the information.

Describe the process of pain conduction.

Pain conduction involves the activation of nociceptors by tissue damage or extreme stimuli, with impulse signals traveling along ascending spinal pathways through the thalamus to the primary somatic sensory cortex.

Define acute pain and its characteristics.

rapid onset occurring immediately after injury, is localized to the stimulus site, is conducted rapidly, and ceases once the stimulus stops.

Explain referred pain and why it occurs.

perceived in a superficial body region far from the actual internal source due to the convergence of sensory neurons from both regions on the same spinal cord segments and ascending tracts.

Describe chronic pain and its association with the central nervous system.

long-lasting pain not tied to immediate direct injury, resulting from misinterpretation or failure of pain-gating pathways in the central nervous system, particularly the thalamus and cerebrum. It is often associated with depression and frustration.

Explain phantom pain and its origin.

the sensation of pain perceived as originating from a limb or body part that has been surgically or traumatically amputated.

Define Wernicke's Area and its function in speech processing.

area is located in the parietal/temporal cortex and is responsible for the comprehension and understanding of spoken and written language, as well as formulating thoughts and words to speak.

What is the consequence of damage to Wernicke's Area?

results in Wernicke aphasia, which is characterized by fluent but meaningless speech and poor language comprehension.

Describe the location and function of Broca's Area.

area is located in the inferior frontal gyrus (anterior) and orchestrates and initiates motor output, commanding the muscles of speech (tongue, lips, larynx) to produce sounds.

What happens when Broca's Area is damaged?

results in Broca aphasia, which leads to non-fluent, slow, and arduous speech output, although comprehension remains intact.

Explain the pathway of sound processing in relation to speech.

first perceived in the primary auditory cortex, then processed in Wernicke's area, sent via neuronal connections to Broca's area, and finally passed to the primary motor cortex for articulation.

Define the characteristics of working memory.

lasts a few seconds to minutes and serves as transient storage required for immediate task execution. Most information is lost immediately unless reinforced.

Describe short-term memory and its retention duration.

lasts from minutes to days and serves as temporary storage. It can be converted into long-term memory through consolidation, but most information is lost within a short time frame.

What is long-term declarative memory and how is it accessed?

can last from days to a lifetime, retains factual knowledge, names, and events. It is accessed via the hippocampus for factual memory and the amygdala for emotional memory.

Explain the process of memory consolidation.

the process through which short-term memories are converted into long-term memories, allowing for retention over extended periods.

Describe the duration and retention of Long-Term Procedural (Implicit) memory.

lasts from days to years or even a lifetime.

Explain the characteristics of Long-Term Procedural (Implicit) memory.

It involves the development and retention of motor skills and habits, such as riding a bike or typing, and is highly stable with only a small amount lost over time.

Do Long-Term Procedural (Implicit) memories fade over time?

Only a small amount of implicit memories is lost over time, indicating high stability.

Define Long-Term Procedural (Implicit) memory.

It is a type of memory responsible for the development and retention of motor skills and habits.

How does Long-Term Procedural (Implicit) memory differ from other memory types?

It is specifically focused on motor skills and habits, unlike other memory types that may involve facts or events.