Exam 3 Brain STUDY guide PDF

Chapter 6 6.1 Amplitude: Intensity of sound waves (Loudness) Frequency: Number of compressions per second measured in hertz (Higher frequency = Higher Pitch) Eardrum vibration and frequency of a sound wave that strikes it: - In the inner ear, Cochlea is located, and within the cochlea Hair ce...

Chapter 6 6.1 Amplitude: Intensity of sound waves (Loudness) Frequency: Number of compressions per second measured in hertz (Higher frequency = Higher Pitch) Eardrum vibration and frequency of a sound wave that strikes it: - In the inner ear, Cochlea is located, and within the cochlea Hair cells are the receptors that lie between the membrane, the fluid when displaced by vibrations trigger those hair cells- causing an action potential. Why are sound vibrations amplified as they pass through the ear? - They are amplified because of the bones in the ear called (Malleus, Incus and stapes) overall lever system allowing better hearing sensitivity. Basilar membrane and auditory receptors - Hair cells are A1 receptors - Basilar membrane is a flexible membrane located within the cochlea Frequency theory: The basilar membrane vibrates in synchrony with the sound and causes auditory nerve axons to produce action potentials at the same frequency. - Higher frequency sounds more excited near the base - Low-frequency sounds more excited near the apex Auditory information contralateral and ipsilateral side - Each hemisphere receives its information from the opposite ear (Contralateral) - Primary auditory cortex (A1)- Auditory imagery located superior temporal cortex- Motion of sound - Only at the cochlear nucleus there is (ipsilateral orientation) Volley Principle - Auditory nerve produces burst of nerve impulses Nerve deafness - Tinnitus- Frequent and constant ringing in the ear - Damaged cochlea, hair cells or A1 - Exposure to loud noises Conductive Ear deafness - Damaged outer and or middle ear, not reaching sound waves to inner ear. - Can hear their own voice clearly Tonotopic map (Functions of the auditory cortex) - In which cells in the cortex are more responsive to preferred tones. Sound shadow- (2000-300 Hz) create the travel shadow Time of arrival- Allows to identity where the sound is coming from Phase difference- Provide cues for localization gives direction of sound waves 6.2 Vestibular Sense - System that detects position and movement of the head Otolith organs and calcium carbonate particles (Vestibular organ) - Otoliths are calcium carbonate particles that push against different hair cells and excite them when the head tilts. Sensory aspect of pain somatosensory cortex - Harmful stimulus- attention grabber - Prefrontal cortex responds pain as long as the pain lasts - Axons carrying pain have little to no myelin making the travel process slower - Motor responses on the other will be fast - Mild pain = glutamate - Higher pain = glutamate with neuropeptides Emotional aspects of pain in the cingulate cortex - Goes through Medulla to several central nuclei of thalamus, amygdala, hippocampus, prefrontal cortex and cingulate cortex. - Similar path to physical pain Morphine mimicking the effects of endorphins - Both morphine and endorphins reduce pain by binding to opioid receptors in the central nervous system. Itches and histamine - Release of histamine produces that itching sensations - Opiates increase itch while antihistamines decrease itch Sodium channels opening in the sense of touch - Stimulation opens sodium channels to trigger an action potential Receptor Location Responds to Free nerve ending Any skin area Pain and temperature Hair-follicle Hair covered skin Movement of hairs Meissner’s corpuscles Hairless skin Movement across skin Pacinian corpuscles Any skin area Vibrations and sudden touch Merkel's disks Any skin area Static touch Ruffini endings Any skin area Skin stretch Krause and bulbs Mostly hairless skin Cold temperature Pacinian corpuscles - Any skin area- Responds to Vibration or sudden touch Meissner’s corpuscles - Hairless Areas - Responds to movement across skin Somatosensory receptor - Sensation of the body and its movements - Differentiate between types of touch; such as pain, itch and tickle. Touch receptors may be: - Simple bare neuron ending - A modified dendrite (Merkel disks) - An elaborated neuron ending - A bare ending surrounded by non-neural cells that modify its function Why is it difficult to tickle oneself? - Already know the motion- lack of anticipation 6.3 Taste and smell with the endopiriform cortex - Flavour is combination of taste and smell - Taste and smell axons are overlapped together in the endopiriform cortex Synesthesia - The experience of one sense in response to stimulation of a different sense - An example would be seeing a number or a letter as a specific color I think of Thursday, fall and number 7 = same vibe. Why can humans identify a wide variety of bitter substances - Bitter is associated with toxic substances which our brain automatically rejects but not one individual substance. Example: a bitter toxic substance and kale both rejected. - This protects us from eating/indulging toxic chemicals. - Bitter taste also triggers our smell sensors Taste receptor - Modified skin cells - Replaced about 10-14 days - Each papillae contains 10 or more taste buds, each taste bud contains 50 receptors Olfaction - Humans tend prefer smell of a potential romantic partner who smells differently from their family– good for future children's immunity. - Only sense that does not go to the thalamus. - Also this sense is only an ipsilateral sense. Receptors: - Located in the cilia Chapter 7 Cardiac, Smooth, & Striated Muscles Cardiac Muscles: Found in the heart, possessing properties of both smooth and skeletal muscles, involuntary. Smooth Muscles: Control the digestive system and other organs; involuntary. Striated (Skeletal) Muscles: Responsible for body movement in relation to the environment; voluntary. Relationship Between Motor Neuron Axons and Muscle Fibers and Precision Precision: The fewer muscle fibers a single axon innervates, the more precise the movement. Muscles involved in fine movements (e.g., eye muscles) have a high ratio of motor neurons to muscle fibers. Neuromuscular Junction Definition: A synapse between a motor neuron axon and a muscle fiber. Function: The release of acetylcholine at this junction excites the muscle, leading to contraction. Antagonistic Muscles Role: Movement is facilitated by alternating contractions of opposing muscle sets (e.g., flexors and extensors). Example: A flexor muscle bends a limb, while an extensor straightens it. Slow-twitch Muscles and Fast-twitch Muscles Slow-twitch: Generate less force, do not fatigue easily, and are aerobic. Fast-twitch: Produce quick, powerful contractions, fatigue rapidly, and are anaerobic. Proprioception and Movement of a Part of the Body Proprioceptors: Detect body position or movement, such as muscle spindles that respond to muscle stretch and Golgi tendon organs that prevent excessive muscle tension. Golgi Tendon Organs Function: Located in tendons, they act as a "brake" to prevent excessive muscle contraction by sending inhibitory signals to the spinal cord. Ballistic Movement Definition: Rapid, pre-programmed movements that cannot be altered once initiated (e.g., the shake of a wet dog). Prefrontal Cortex and Signals for a Movement Function: Stores sensory information relevant to a movement and evaluates potential outcomes before executing the movement. Cerebellum and Precise Timing Role: Coordinates balance, timing, and precision of movement, crucial for rapid, sequential tasks and attention shifts. Basal Ganglia: Caudate Nucleus, Putamen, and Globus Pallidus Structures: ○ Caudate Nucleus and Putamen: Receive input from the cortex and send output to the globus pallidus. ○ Globus Pallidus: Inhibits the thalamus to regulate movement initiation. Parkinson’s Disease and the Substantia Nigra Dopamine Release: Substantia nigra sends dopamine-releasing axons to the caudate nucleus and putamen, and its degeneration leads to motor issues. Why a Dopamine Pill is Ineffective for Treating Parkinson’s Disease Reason: Dopamine cannot cross the blood-brain barrier; hence, pills would not reach affected brain regions. Main Symptom of Parkinson’s Disease Key Symptom: Muscle tremors, alongside rigidity and bradykinesia (slowness of movement). Early Symptoms of Huntington’s Disease Initial Signs: Arm jerks and facial twitches that progress into more severe motor dysfunctions. Psychological Disorders Accompanying Huntington's Disease Disorders: Depression, memory impairment, anxiety, hallucinations, poor judgment, and substance abuse. The Gene That Controls Huntington’s Disease and the Normal/Abnormal Repetitions Gene: An autosomal dominant gene on chromosome #4. Repetitions: Normal range has fewer C-A-G repeats; more than a certain number indicates a higher risk and earlier onset. A Readiness Potential Definition: Activity in the motor cortex that precedes voluntary movement, occurring about 200 milliseconds before action. Supplementary Motor Cortex Function: Organizes sequences of movement, corrects errors, and is involved in planning rapid, complex actions. Active before movement and after errors to prevent repetition. Chapter 8 Circadian Rhythms: Biological cycles that last about 24 hours, influencing sleep-wake patterns and other bodily functions. Endogenous: Internal biological processes not solely dependent on external cues. Zeitgebers: External cues like light that help regulate circadian rhythms. Suprachiasmatic Nucleus (SCN): Location: Part of the hypothalamus, located above the optic chiasm. Damage: Can disrupt circadian rhythms, leading to irregular sleep-wake cycles. Retinohypothalamic Path: Pathway that connects the retina to the SCN, transmitting light information to regulate sleep. Melatonin and Pineal Gland: The pineal gland secretes melatonin, which helps regulate sleep. Melatonin Supplements: Most effective when taken in the evening to aid sleep. Sleep Cycle: Alpha Waves: Relaxed, awake state (Maybe eyes closed). Stage 1: Light sleep with slow eye movement. Stage 2: Includes sleep spindles and K-complexes. Stage 3 & 4: Deep sleep (slow-wave sleep). REM (Rapid Eye Movement): Dreaming stage, known as paradoxical sleep due to brain activity resembling wakefulness. NREM (Non-REM): Includes stages 1-4. Orexin: Neurotransmitter involved in wakefulness and arousal. Sleep Apnea: Breathing interruptions during sleep, common in overweight individuals and older adults. Narcolepsy: Condition characterized by sudden sleep attacks and excessive daytime sleepiness. Activation-Synthesis Hypothesis: Theory that dreams are the brain's attempt to make sense of random neural activity during REM sleep. Cataplexy: Sudden muscle weakness or paralysis while awake, often triggered by strong emotions. Evolutionary Perspective of Sleep: Suggests sleep evolved to conserve energy and provide protection during the night. PER and TIM Proteins: Involved in the regulation of circadian rhythms. Sleep Spindles: Short bursts of brain activity in stage 2 sleep. K-Complexes: Large, slow waves that occur during stage 2 sleep. Basal Forebrain and Acetylcholine: Area that promotes wakefulness and arousal; acetylcholine enhances REM sleep. Allergy Medication and Histamine: Some allergy medications block histamine, leading to drowsiness.