Endogenous and Exogenous Substances PDF

**Endogenous Substances** **Definition:** Endogenous substances are naturally occurring compounds produced by the body.\ **Importance:** They play vital roles in physiological processes, such as hormones (e.g., insulin) and neurotransmitters (e.g., dopamine). **Exogenous Substances** **Definition...

**Endogenous Substances** **Definition:** Endogenous substances are naturally occurring compounds produced by the body.\ **Importance:** They play vital roles in physiological processes, such as hormones (e.g., insulin) and neurotransmitters (e.g., dopamine). **Exogenous Substances** **Definition:** Exogenous substances originate from outside the body, such as drugs, toxins, and nutrients.\ **Importance:** Their effects can significantly impact bodily functions, sometimes beneficially (e.g., medications) or harmful (e.g., drugs). **Neurotransmitter** **Definition:** Neurotransmitters are chemical messengers that transmit signals across synapses between neurons.\ **Importance:** They are crucial for communication within the nervous system, affecting mood, perception, and bodily functions. **Acetylcholine** **Definition:** A neurotransmitter involved in muscle activation, memory, and learning.\ **Importance:** It plays a role in the autonomic nervous system and is linked to Alzheimer\'s disease when levels are disrupted. **Dopamine** **Definition:** A neurotransmitter associated with pleasure, motivation, and reward.\ **Importance:** It influences mood, attention, and motor control. Dysregulation is linked to disorders like Parkinson\'s and schizophrenia. **Norepinephrine** **Definition:** A neurotransmitter and hormone involved in the body\'s \"fight or flight\" response.\ **Importance:** It affects arousal, attention, and stress response. Abnormal levels can contribute to anxiety and depression. **Glutamate** **Definition:** The primary excitatory neurotransmitter in the brain.\ **Importance:** It plays a critical role in learning, memory, and overall brain function. Excessive glutamate can lead to neurotoxicity. **Serotonin** **Definition:** A neurotransmitter that regulates mood, appetite, and sleep.\ **Importance:** Low levels are linked to depression and anxiety disorders. Many antidepressants target serotonin pathways. **GABA (Gamma-Aminobutyric Acid)** **Definition:** The main inhibitory neurotransmitter in the brain.\ **Importance:** It helps regulate anxiety, muscle tension, and sleep. Many anti-anxiety medications enhance GABA activity. **Endorphin** **Definition:** Neurotransmitters that act as natural painkillers and mood enhancers.\ **Importance:** They are released during exercise, stress, and pain, contributing to feelings of euphoria. **Cerebral Hemispheres** **Definition:** The two halves of the brain, each responsible for different functions.\ **Importance:** The left hemisphere typically handles language and analytical tasks, while the right hemisphere is associated with creativity and spatial abilities. **Frontal Lobe** **Definition:** The brain region associated with reasoning, planning, problem-solving, and emotional regulation.\ **Importance:** It plays a crucial role in executive functions and personality. **Parietal Lobe** **Definition:** The region responsible for processing sensory information and spatial awareness.\ **Importance:** It integrates sensory inputs and contributes to perception and movement coordination. **Occipital Lobe** **Definition:** The visual processing center of the brain.\ **Importance:** It interprets visual stimuli and is essential for vision-related tasks. **Temporal Lobe** **Definition:** The area involved in auditory processing and memory.\ **Importance:** It plays a role in recognizing faces and understanding language. **Hypothalamus** **Definition:** A small brain region that regulates homeostasis, including temperature, hunger, and thirst.\ **Importance:** It links the nervous system to the endocrine system via the pituitary gland. **Pituitary Gland** **Definition:** The \"master gland\" that controls various hormonal functions.\ **Importance:** It regulates growth, metabolism, and reproductive processes through hormone release. **Amygdala** **Definition:** An almond-shaped structure involved in emotion processing and memory.\ **Importance:** It plays a crucial role in fear responses and emotional regulation. **Hippocampus** **Definition:** A brain region essential for memory formation and spatial navigation.\ **Importance:** It is involved in the consolidation of information from short-term to long-term memory. **Wilder Penfield** **Definition:** A neurosurgeon known for his pioneering work in mapping the brain\'s functions through electrical stimulation.\ **Importance:** His findings advanced understanding of the brain\'s cortical organization and treatment for epilepsy. **Motor Cortex** **Definition:** The area of the cerebral cortex that controls voluntary movements.\ **Importance:** Different regions correspond to different body parts, allowing precise movement control. **Somatosensory Cortex** **Definition:** The brain region that processes sensory input from the body.\ **Importance:** It interprets touch, temperature, pain, and proprioception. **Scanning Techniques** **Definition:** Various methods to visualize brain structure and activity.\ **Importance:** Techniques like EEG, CT, MRI, and PET provide insights into brain function and pathology. **EEG (Electroencephalogram)** **Definition:** A test that records electrical activity in the brain.\ **Importance:** It helps diagnose conditions like epilepsy and sleep disorders. **Brain Waves** **Definition:** Electrical impulses in the brain measured by EEG, categorized into delta, theta, alpha, beta, and gamma waves.\ **Importance:** Different brain states correspond to various mental activities and levels of consciousness. **CT Scan (Computed Tomography)** **Definition:** A medical imaging technique that uses X-rays to create detailed cross-sectional images of the body.\ **Importance:** Useful for diagnosing injuries and brain abnormalities. **MRI (Magnetic Resonance Imaging)** **Definition:** An imaging technique that uses strong magnets and radio waves to create detailed images of organs and tissues.\ **Importance:** Particularly effective for imaging the brain and spinal cord. **PET (Positron Emission Tomography)** **Definition:** An imaging test that uses radioactive tracers to visualize metabolic processes in the body.\ **Importance:** Useful for assessing brain function and diagnosing conditions like Alzheimer's. **Selective Attention** **Definition:** The process of focusing on a particular object or task while ignoring others.\ **Importance:** It enables efficient processing of relevant information in a complex environment. **Cameron Motte** **Definition:** A notable figure who underwent hemispherectomy to treat severe epilepsy.\ **Importance:** His case exemplifies brain plasticity and recovery after significant surgical intervention. **Hemispherectomy** **Definition:** A surgical procedure that involves removing or disconnecting one hemisphere of the brain.\ **Importance:** It is often performed to control severe epilepsy, particularly in children, with remarkable outcomes. **Neuroplasticity** **Definition:** The brain\'s ability to reorganize itself by forming new neural connections throughout life.\ **Importance:** It allows recovery from injury and adaptation to new experiences. **Divided Brain** **Definition:** Refers to the functional specialization of the two hemispheres of the brain.\ **Importance:** Each hemisphere has distinct roles, with the left typically associated with language and the right with spatial tasks. **Inattentional Blindness** **Definition:** A psychological phenomenon where individuals fail to perceive objects in their visual field when focused on a specific task.\ **Importance:** It highlights limitations in attention and awareness. **Monkey Business Illusion** **Definition:** A visual illusion that demonstrates inattentional blindness, where viewers miss obvious changes in a scene while focusing on a task.\ **Importance:** It illustrates how attention can affect perception. **Change Blindness** **Definition:** A phenomenon where a change in a visual stimulus goes unnoticed by the observer.\ **Importance:** It shows limitations in visual perception and attention. **Sequential Processing** **Definition:** A cognitive process that involves analyzing information one step at a time.\ **Importance:** It is often used in tasks requiring focused attention and logical reasoning. **Parallel Processing** **Definition:** The simultaneous processing of multiple aspects of information.\ **Importance:** It allows for quicker responses and the ability to manage complex stimuli. **Sensation** **Definition:** The process of detecting physical stimuli through sensory receptors.\ **Importance:** It is the first step in experiencing the world around us. **Perception** **Definition:** The interpretation and organization of sensory information.\ **Importance:** It enables individuals to make sense of their sensory experiences. **Absolute Threshold** **Definition:** The minimum level of stimulus intensity needed to detect a stimulus 50% of the time.\ **Importance:** It defines the limits of human perception. **Difference Threshold** **Definition:** The smallest detectable difference between two stimuli, also known as the just noticeable difference (JND).\ **Importance:** It helps understand sensory discrimination. **Signal Detection Theory** **Definition:** A theory that explains how we detect signals amidst noise, incorporating decision-making processes.\ **Importance:** It emphasizes the subjective nature of perception, influenced by various factors like expectations and biases. **Sensory Receptors** **Definition:** Specialized cells that detect sensory stimuli and convert them into neural signals.\ **Importance:** They are crucial for all sensory modalities, including vision, hearing, and touch. **Transduction** **Definition:** The process of converting physical energy from stimuli into electrical signals that can be interpreted by the brain.\ **Importance:** It is essential for all sensory systems. **Sensory Adaptation** **Definition:** The diminished sensitivity to a stimulus as a result of constant exposure.\ **Importance:** It allows individuals to focus on changes in the environment rather than constant stimuli. **Photons** **Definition:** The basic units of light and all other forms of electromagnetic radiation.\ **Importance:** They are crucial for vision, as light enters the eye in the form of photons. **Visible Spectrum** **Definition:** The portion of the electromagnetic spectrum that is visible to the human eye.\ **Importance:** It encompasses wavelengths from approximately 380 to 750 nanometers. **Cornea** **Definition:** The transparent front layer of the eye that helps focus light.\ **Importance:** It is crucial for clear vision, providing a protective barrier as 4o mini **Lens** **Definition:** A transparent structure behind the cornea that helps focus light onto the retina.\ **Importance:** It adjusts shape for near and distant vision through a process called accommodation. **Accommodation** **Definition:** The process by which the eye\'s lens changes shape to focus on objects at varying distances.\ **Importance:** It allows for clear vision across different ranges, critical for daily tasks. **Retina** **Definition:** The light-sensitive layer at the back of the eye that converts light into neural signals.\ **Importance:** Contains photoreceptors (rods and cones) essential for vision. **Rods** **Definition:** Photoreceptor cells in the retina that are sensitive to low light levels.\ **Importance:** They enable night vision and peripheral vision but do not detect color. **Cones** **Definition:** Photoreceptor cells in the retina responsible for color vision and detail.\ **Importance:** They function best in bright light and are concentrated in the fovea. **Fovea** **Definition:** A small central pit in the retina that provides the clearest vision.\ **Importance:** It is densely packed with cones, allowing for sharp central vision. **Optic Nerve** **Definition:** The nerve that transmits visual information from the retina to the brain.\ **Importance:** It is critical for the perception of sight, connecting the eye to the visual cortex. **Trichromatic Theory** **Definition:** A theory of color vision that states the eye has three types of cones sensitive to red, green, and blue light.\ **Importance:** It explains how we perceive a wide range of colors through combinations of these three primary colors. **Opponent-Process Theory** **Definition:** A theory suggesting that color perception is controlled by the activity of opposing neural processes (e.g., red-green, blue-yellow).\ **Importance:** It accounts for color afterimages and some aspects of color vision. **Afterimage** **Definition:** A visual illusion in which an image continues to appear after exposure to the original image has ceased.\ **Importance:** It demonstrates the workings of the opponent-process theory in color vision. **Color Blindness** **Definition:** A genetic condition where individuals cannot perceive certain colors accurately, often due to missing cone types.\ **Importance:** It primarily affects the ability to distinguish between red and green, impacting daily life. **Nearsightedness (Myopia)** **Definition:** A vision condition where distant objects appear blurry while close objects can be seen clearly.\ **Importance:** It occurs when the eye is too long or the cornea is too curved, requiring corrective lenses or surgery. **Farsightedness (Hyperopia)** **Definition:** A vision condition where nearby objects are blurry while distant objects can be seen clearly.\ **Importance:** It results from a shorter eye or flatter cornea, often correctable with glasses. **Visual Cliff Study (Eleanor Gibson and Richard Walk, 1960)** **Definition:** An experiment demonstrating depth perception in infants using a simulated cliff.\ **Importance:** Findings suggested that depth perception is innate, as infants showed reluctance to crawl over the \"cliff.\" **Gestalt Laws of Organization** **Definition:** Principles describing how we perceive visual elements as organized wholes.\ **Importance:** They include concepts like closure, proximity, similarity, and simplicity, which guide perception. **Closure** **Definition:** The tendency to perceive incomplete shapes as complete figures.\ **Importance:** It helps in recognizing objects even when parts are missing. **Proximity** **Definition:** The principle that objects near each other tend to be grouped together.\ **Importance:** It affects how we interpret spatial relationships in visual scenes. **Similarity** **Definition:** The tendency to group similar objects together.\ **Importance:** It aids in identifying patterns and organizing visual information. **Simplicity** **Definition:** The preference for the simplest interpretation of a visual arrangement.\ **Importance:** It guides perception to favor straightforward forms and structures. **Blue Dress/Gold Dress** **Definition:** A viral optical illusion that sparked debate about color perception based on lighting conditions.\ **Importance:** It illustrates subjective differences in color perception and the role of contextual cues. **Laurel vs. Yanni** **Definition:** An auditory illusion where listeners hear either \"Laurel\" or \"Yanni\" based on frequency emphasis.\ **Importance:** It highlights differences in auditory perception and processing. **Charles Limb; Building Musical Muscle TED Talk** **Definition:** A TED Talk by neuroscientist Charles Limb discussing the brain\'s response to music.\ **Importance:** He explores how improvisation and musical creativity activate specific brain regions. **Semantic Specificity** **Definition:** The concept that specific words or phrases activate distinct neural patterns related to their meaning.\ **Importance:** It relates to how language and meaning are processed in the brain. **Hammer, Anvil, Stirrup** **Definition:** The three tiny bones in the middle ear that transmit sound vibrations from the eardrum to the inner ear.\ **Importance:** They amplify sound and are essential for hearing. **Inner Ear** **Definition:** The innermost part of the ear that includes the cochlea and vestibular system.\ **Importance:** It converts sound vibrations into neural signals for the brain. **Cochlea** **Definition:** A spiral-shaped structure in the inner ear that contains the sensory receptors for hearing.\ **Importance:** It plays a key role in converting sound waves into electrical signals. **Basilar Membrane** **Definition:** A membrane in the cochlea that moves in response to sound waves, stimulating hair cells.\ **Importance:** Its movement helps transduce sound into nerve impulses. **Hearing Loss** **Definition:** A partial or total inability to hear.\ **Importance:** It can be caused by various factors, including aging, noise exposure, and genetic conditions. **Sensorineural Hearing Loss** **Definition:** Hearing loss resulting from damage to the inner ear or auditory nerve.\ **Importance:** It is often permanent and can be caused by factors like aging or exposure to loud sounds. **Conduction Hearing Loss** **Definition:** Hearing loss caused by problems in the outer or middle ear that prevent sound from being conducted to the inner ear.\ **Importance:** It may be temporary or correctable with medical intervention. **Sound Shadow** **Definition:** The phenomenon where a sound is perceived to be quieter on one side due to the head blocking sound waves.\ **Importance:** It helps in localizing the source of sounds based on their intensity differences. **Place Theory** **Definition:** A theory that explains pitch perception based on the location of activated hair cells along the cochlea.\ **Importance:** It accounts for how different pitches stimulate different areas of the cochlea. **Frequency Theory** **Definition:** A theory that proposes pitch is determined by the frequency of nerve impulses traveling up the auditory nerve.\ **Importance:** It explains how we perceive low frequencies but is less effective for high-frequency sounds. **Pressure** **Definition:** A tactile sensation detected by mechanoreceptors in the skin.\ **Importance:** It contributes to the perception of texture and touch. **Warmth** **Definition:** A tactile sensation associated with heat detected by thermoreceptors.\ **Importance:** It helps in identifying temperature changes in the environment. **Cold** **Definition:** A tactile sensation associated with coolness detected by thermoreceptors.\ **Importance:** It alerts individuals to potential hazards (e.g., frostbite). **Pain** **Definition:** An unpleasant sensory and emotional experience associated with actual or potential tissue damage.\ **Importance:** It serves as a protective mechanism, alerting individuals to injury. **Nociceptors** **Definition:** Sensory receptors that detect pain stimuli.\ **Importance:** They play a crucial role in the perception of pain and protective responses. **Gustation** **Definition:** The sense of taste, involving the detection of flavor compounds through taste buds.\ **Importance:** It contributes to food preferences and dietary choices. **Flavor** **Definition:** The combination of taste and smell that produces a unique sensory experience when consuming food.\ **Importance:** It enhances the enjoyment of eating and can influence eating habits. **Taste Buds** **Definition:** Sensory organs on the tongue that detect taste stimuli.\ **Importance:** They are responsible for perceiving the five basic tastes: sweet, sour, salty, bitter, and umami. **Five Tastes** **Definition:** The basic categories of taste perception: sweet, sour, salty, bitter, and umami (savory).\ **Importance:** Each taste plays a role in nutrition and dietary preferences. **Olfaction** **Definition:** The sense of smell, involving the detection of airborne chemicals through olfactory receptors.\ **Importance:** It contributes to flavor perception and is closely linked to memory and emotion. **Pheromones** **Definition:** Chemical signals released by an organism that affect the behavior or physiology of others of the same species.\ **Importance:** They play roles in communication, mating, and social behaviors. **Summarizing the Senses** **Definition:** An overview of how the senses (sight, hearing, touch, taste, and smell) contribute to perception and interaction with the environment.\ **Importance:** Understanding sensory systems helps in fields like psychology, marketing, and health. **Optical Illusions** **Definition:** Visual phenomena that trick the brain into perceiving something differently than it actually is.\ **Importance:** They provide insight into the complexities of visual perception. **Three-Pronged Trident** **Definition:** An optical illusion that appears to have three prongs but is perceived as having a different number depending on viewing angles.\ **Importance:** It illustrates how perspective affects visual interpretation. **Mueller-Lyer Illusion** **Definition:** An optical illusion where two lines of equal length appear to be different lengths due to arrow-like ends.\ **Importance:** It demonstrates how context and framing can influence perception. **Why Do We Sleep?** **Definition:** A question addressing the purpose of sleep, which includes restorative processes and memory consolidation.\ **Importance:** Sleep is crucial for physical health, cognitive function, and emotional well-being. **Biological Rhythms** **Definition:** Regular, cyclic patterns of biological activity, including sleep-wake cycles and hormonal fluctuations.\ **Importance:** They regulate physiological processes and are influenced by environmental cues. **Circadian Rhythms** **Definition:** Biological cycles that occur approximately every 24 hours, such as the sleep-wake cycle.\ **Importance:** They synchronize physiological processes with the day-night cycle, influencing sleep, alertness, and metabolism. **Suprachiasmatic Nucleus (SCN)** **Definition:** A group of neurons in the hypothalamus that regulates circadian rhythms.\ **Importance:** It acts as the body\'s master clock, responding to light and dark cycles. **Melatonin** **Definition:** A hormone produced by the pineal gland that regulates sleep-wake cycles.\ **Importance:** It is released in response to darkness, promoting sleepiness. **Owl** **Definition:** A term often used to describe people who naturally stay up late and wake later.\ **Importance:** It highlights individual differences in circadian rhythms and sleep patterns. **Lark** **Definition:** A term used for individuals who wake up early and feel most alert in the morning.\ **Importance:** It reflects the variations in sleep preferences among people. **Sleep Deprivation** **Definition:** The condition resulting from insufficient sleep, affecting cognitive and physical performance.\ **Importance:** Chronic sleep deprivation can lead to serious health issues, including impaired immune function and mood disorders. **Does Everyone Need 8 Hours of Sleep?** **Definition:** A common inquiry regarding the optimal amount of sleep needed for health.\ **Importance:** Sleep needs vary by individual, influenced by age, lifestyle, and health, with some needing more or less than the typical 7-9 hours recommended for adults.