EXAM 4 - I WILL PASS! PDF

Brain 1. Identify the major parts of the brain and list their main functions: ○ Cerebrum: Sensory perception, voluntary motor control, memory, emotion, and higher cognitive functions like decision-making and language. ○ Diencephalon: Thalamus: Relay ce...

Brain 1. Identify the major parts of the brain and list their main functions: ○ Cerebrum: Sensory perception, voluntary motor control, memory, emotion, and higher cognitive functions like decision-making and language. ○ Diencephalon: Thalamus: Relay center for sensory, motor, and emotional signals. Hypothalamus: Regulates autonomic functions, circadian rhythms, hunger, thirst, and endocrine activity. ○ Cerebellum: Coordinates learned motor patterns, posture, and fine-tunes movements. ○ Brainstem: Midbrain: Reflexes to visual/auditory stimuli, motor regulation, and alertness. Pons: Respiratory control, links cerebellum to other parts of the brain. Medulla Oblongata: Cardiovascular/respiratory control, reflex centers, and sensory-motor relay. 2. Identify the lobes and major regions of the cerebral cortex, and list their functions: ○ Frontal: Motor control, problem-solving, language production. ○ Parietal: Sensory processing (touch, pressure). ○ Temporal: Auditory perception, memory. ○ Occipital: Visual processing. 3. Electroencephalogram: ○ Put the waves in order from highest to lowest frequency: Beta (>13 Hz) → Alpha (8–13 Hz) → Theta (3.5–7.5 Hz) → Delta (≤3 Hz). ○ Tell which mental state each wave is most associated with: Beta: Awake and alert. Alpha: Relaxed but awake. Theta: Light sleep or deep relaxation. Delta: Deep sleep. Motor Control and Descending Spinal Pathways 1. Define upper and lower motor neuron: ○ Upper Motor Neuron: Begins in the brain; controls lower motor neurons. ○ Lower Motor Neuron: Begins in the spinal cord or brainstem and directly stimulates muscles. 2. Define decussation: ○ Decussation is the crossing of nerve fibers to the opposite side (e.g., corticospinal tracts).  3. Describe the motor homunculus (the map of the body) on the primary motor cortex: ○ It’s a visual representation of body regions controlled by the primary motor cortex. Areas requiring fine motor control, like hands and face, are larger. 4. Summarize the functions of the corticospinal, medial, and lateral motor pathways: ○ Corticospinal Pathway: Voluntary motor control (e.g., limbs). ○ Medial Pathway: Posture, balance, and reflexive movements. ○ Lateral Pathway: Fine control of distal muscles. 5. Describe the roles of the basal nuclei and cerebellum in movements controlled by the motor cortex: ○ Basal Nuclei: Suppress unnecessary movements and facilitate desired ones. ○ Cerebellum: Compares intended movements with sensory feedback to make corrections. The General Senses and Ascending Spinal Pathways 1. Describe the ascending sensory pathways (tracts through the spinal cord): ○ Posterior Column Pathway: Fine touch, vibration, proprioception. ○ Spinothalamic Pathway: Pain, temperature, and crude touch. ○ Spinocerebellar Pathway: Proprioceptive input to the cerebellum. 2. Define nociceptor, thermoreceptor, mechanoreceptor, and chemoreceptor: ○ Nociceptor: Detects pain. ○ Thermoreceptor: Detects temperature changes. ○ Mechanoreceptor: Detects touch, pressure, and vibration. ○ Chemoreceptor: Detects chemical stimuli (e.g., pH, oxygen). 3. Classify tactile skin receptors by depth in the skin, size of receptive field, and rate of adaptation: ○ Superficial (Small Receptive Fields): Tactile discs, tactile corpuscles. ○ Deep (Large Receptive Fields): Lamellar corpuscles, bulbous corpuscles. ○ Rate of Adaptation: Phasic (fast-adapting), Tonic (slow-adapting). 4. Tell where 3 types of proprioceptors that give information about joint position are located: ○ Free Nerve Endings: In joint capsules. ○ Muscle Spindles: In muscles, detecting length changes. ○ Golgi Tendon Organs: In tendons, detecting tension. 5. Describe the sensory homunculus (the map of the body) on the somatosensory cortex: ○ Shows body regions corresponding to sensory processing in the brain; larger areas represent regions with more sensory receptors (e.g., hands, lips). 6. Explain approaches to analgesia (including gate control theory, discussed in lecture but not the book):  ○ Gate Control Theory: Non-painful stimuli (e.g., rubbing) block pain signals at the spinal cord. ○ Analgesics: NSAIDs block inflammation; opioids inhibit pain signal transmission. 7. Tell about referred pain: ○ Pain felt in a location other than its source (e.g., left arm pain during a heart attack). Sensory Systems: Common Characteristics 1. Sensory transduction: ○ A stimulus is converted into a receptor potential, leading to action potentials. 2. Sensory modality: ○ Receptor Specificity: Specific receptors detect specific stimuli (e.g., photoreceptors for light). ○ Labeled Line: The pathway conveying specific sensory information to the brain. 3. Stimulus localization: ○ Determined by the size of receptive fields and cortical mapping. 4. Coding of stimulus intensity: ○ Graded Receptor Potentials: Stronger stimuli increase potential. ○ Frequency Coding: Stimulus strength increases action potential frequency. 5. Timing: ○ Phasic Receptors: Detect changes; adapt quickly. ○ Tonic Receptors: Detect sustained stimuli; adapt slowly. Olfaction 1. Describe the olfactory epithelium, including olfactory receptor cells and their replacement: ○ Contains receptors, supporting cells, and basal cells (regenerate). 2. Describe olfactory transduction: ○ Odorant binds receptor → Activates second messenger → Opens ion channels → Action potential. 3. Explain the principles of discriminating or identifying odors: ○ Unique receptor combinations are activated by each odorant; the brain interprets this pattern. Gustation  1. Describe the structure of taste buds within lingual papillae (including replacement of gustatory cells): ○ Taste buds are in papillae (fungiform, vallate, foliate) and contain gustatory cells that are replaced regularly. 2. Explain gustatory discrimination: ○ Five tastes: Sweet (sugars), sour (acids), salty (sodium), bitter (alkaloids), umami (amino acids). Vision 1. Describe structures of the eye itself: ○ Cornea, lens, retina, aqueous humor (fluid maintaining pressure). 2. Describe the circulation of aqueous humor, and tell the basis of glaucoma: ○ Blocked drainage increases pressure, damaging the optic nerve. 3. Explain accommodation (focusing): ○ Lens Rounds: For near vision. ○ Lens Flattens: For distant vision. 4. Abnormalities in focusing: ○ Myopia (Near-sighted): Corrected by diverging lenses. ○ Hyperopia (Far-sighted): Corrected by converging lenses. 5. Explain phototransduction: ○ Light triggers hyperpolarization of photoreceptors → Neural signals. 6. Compare rods and cones: ○ Rods: Sensitive to low light. ○ Cones: Sensitive to color and sharp detail. 7. Describe visual pathways in the CNS, including how decussation occurs: ○ Retina → Optic nerve → Optic chiasm (fibers cross) → Visual cortex. 8. Tell how depth perception is accomplished: ○ Overlapping visual fields from both eyes. Hair Cells (Mechanoreceptors for Both Equilibrium and Audition) 1. Draw the receptor potential that would result with each direction of stereocilia movement: ○ Neutral Position: Some ion channels are open, causing a baseline receptor potential. ○ Bent Toward the Tallest Stereocilia: Ion channels open more, increasing depolarization and action potential frequency. ○ Bent Toward the Shortest Stereocilia: Ion channels close, hyperpolarizing the cell and decreasing action potential frequency.  2. Predict the change of action potential frequency in an auditory neuron as its hair cell is stimulated: ○ Increase in Stereocilia Bending Toward the Tallest: Increased action potential frequency. ○ Decrease or Opposite Bending: Decreased action potential frequency. Equilibrium 1. Explain how the maculae give information about head tilt or movement (static equilibrium): ○ Maculae are located in the utricle and saccule. ○ Otoliths (calcium carbonate crystals) rest on a gelatinous layer over hair cells. ○ Head tilt or linear acceleration causes otoliths to shift, bending stereocilia and generating signals about head position or motion. 2. Explain how the semicircular ducts give information about head rotation (dynamic equilibrium): ○ Semicircular ducts contain ampullae with crista ampullaris (hair cells covered by a gelatinous cupula). ○ Rotation causes endolymph (fluid) to lag behind, bending the cupula and stereocilia, signaling rotational movement. 3. Describe pathways for equilibrium in the CNS: ○ Signals from vestibular apparatus travel via the vestibular nerve to the vestibular nuclei in the brainstem and the cerebellum. ○ These centers integrate data to control posture, balance, and coordinate eye movements. Hearing 1. Describe how sound moves through the outer and middle ear: ○ Outer Ear: Sound waves enter the external acoustic meatus and vibrate the tympanic membrane. ○ Middle Ear: Vibrations are transmitted through the ossicles (malleus, incus, stapes) to the oval window, amplifying the sound. 2. Tell how muscles in the middle ear can protect the inner ear: ○ Tensor Tympani and Stapedius Muscles: Contract in response to loud sounds to dampen vibrations and protect the cochlea from damage. 3. Explain how fluid waves in the cochlea cause side-to-side movements of the hair cell stereocilia: ○ Vibrations at the oval window generate waves in the perilymph (fluid) of the cochlea.  ○ Waves move the basilar membrane, causing hair cells' stereocilia in the organ of Corti to bend against the tectorial membrane. ○ This bending opens ion channels, creating receptor potentials. 4. Tell how frequency is detected in the cochlea: ○ High Frequencies: Vibrate the basilar membrane near the oval window (stiffer region). ○ Low Frequencies: Vibrate the basilar membrane farther from the oval window (more flexible region). 5. Explain the two main ways a sound is localized by comparing sound at the two ears: ○ Interaural Time Difference (ITD): Differences in the arrival time of sound between ears help localize low-frequency sounds. ○ Interaural Intensity Difference (IID): Differences in loudness between ears help localize high-frequency sounds.