mc guided review

Nervous System & Neurons

  1. The Central Nervous System (CNS) consists of the brain and spinal cord, serving as the control center for processing information.

  2. The Peripheral Nervous System (PNS) connects the CNS to the rest of the body and includes the autonomic Nervous System, which controls involuntary functions, and the somatic Nervous System, which controls voluntary movements.

  3. The Autonomic Nervous System is further divided into the sympathetic division, which activates the “fight or flight” response, and the parasympathetic division, which promotes relaxation and “rest and digest.”

  4. The Somatic Nervous System controls voluntary movements by transmitting signals from the brain to the muscles.

  5. Motor (efferent) neurons carry signals from the CNS to the muscles, while sensory (afferent) neurons send signals from sensory receptors to CNS. Interneurons process information between these two.

  6. Glial cells support neurons by providing nutrition, insulation, and support.

Neural Communication & Disorders

  1. An action potential follows the all-or-none principle, meaning it either fires completely or not at all.

  2. During depolarization, the neuron becomes positively charged as sodium ions rush in.

  3. The time period when a neuron cannot fire again immediately is called the refractory period.

  4. When a neuron is at rest, it has a negative charge inside compared to the outside.

  5. Diseases like Multiple Sclerosis and Myasthenia Gravis affect the nervous system by damaging myelin or interfering with neurotransmitter transmission, leading to motor control issues.

Neurotransmitters

  1. GABA is the brain’s primary inhibitory neurotransmitter, promoting relaxation.

  2. Substance P is involved in the perception of pain.

  3. Endorphins act as natural painkillers, reducing pain.

  4. Serotonin affects mood and emotional stability.

  5. Acetylcholine (ACh) is crucial for muscle movement and memory.

  6. Dopamine plays a role in reward and movement, with imbalances linked to Parkinson’s and schizophrenia.

  7. Hormones, released by the endocrine system, influence behavior and physiological processes. Unlike neurotransmitters, hormones travel through the bloodstream and have slower (faster/slower) but longer-lasting effects.

  8. Agonists increase neurotransmitter activity, while antagonists decrease it by blocking receptors.

Drugs & Their Effects

  1. Stimulants like caffeine and cocaine increase nervous system activity, increasing alertness and energy.

  2. Depressants like alcohol and benzodiazepines decrease nervous system activity, leading to relaxation or drowsiness.

  3. Hallucinogens like LSD and psilocybin alter perception and may cause hallucinations.

Studying the Brain & Neuroplasticity

  1. MRI (Magnetic Resonance Imaging) uses magnetic imaging to show detailed brain structures and activity.

  2. EEG (Electroencephalogram) measures electrical activity in the brain and is useful for studying sleep and seizures.

  3. Lesion studies involve examining brain function by observing behavior after damage to specific areas.

  4. Neuroplasticity refers to the brain’s ability to adapt by forming new connections after injury or learning experiences.

Brain Structures & Functions

  1. The brainstem includes:

    • The medulla, which controls vital functions like breathing and heart rate.

    • The Reticular Activating System (RAS), which regulates arousal and wakefulness.

  2. The Limbic System is crucial for emotions and memory. It includes:

    • The hippocampus, which is essential for memory formation.

    • The amygdala, which processes emotions.

    • The hypothalamus, which regulates hunger, thirst, and temperature and maintains homeostasis.

  3. The Thalamus acts as the brain’s relay center, directing sensory information to the appropriate cortical areas.

  4. Hemispheric Specialization means the left hemisphere is generally responsible for language and logic, while the right hemisphere processes spatial and creative tasks.

  5. Contralateral organization means the left side of the brain controls the right side of the body, and vice versa.

Lobes of the Brain & Their Functions

  1. The occipital lobe processes vision.

  2. The frontal lobe is responsible for decision-making, planning, and voluntary movement.

  3. The temporal lobe plays a role in hearing and language comprehension.

  4. The parietal lobe integrates sensory information.

  5. Association Areas include:

    • The prefrontal cortex, which is involved in executive functions.

    • Wernicke’s Area, which is important for language comprehension.

    • Broca’s Area, which is essential for speech production.

Sleep & Consciousness

  1. The Circadian Rhythm is the body’s natural 24-hour cycle, influenced by light exposure.

  2. REM sleep is associated with vivid dreams and is crucial for memory processing. If deprived, people experience REM rebound, leading to an increase in REM sleep when they finally rest.

  3. Dream Theories:

    • Activation Synthesis suggests that dreams are the brain’s way of making sense of random neural activity.

    • Consolidation Theory argues that dreams help us process and store memories.

  4. Sleep Disorders:

    • Insomnia involves difficulty falling or staying asleep.

    • Narcolepsy causes sudden, uncontrollable episodes of sleep.

    • Sleep Apnea leads to repeated disruptions in breathing during sleep.

Sensation & Perception

  1. Transduction is the process of converting sensory stimuli into neural signals the brain can interpret.

  2. Parts of the Eye:

    • The retina contains photoreceptors that detect light.

    • The fovea is the area of the retina with the highest concentration of cones for sharp vision.

  3. Photoreceptors:

    • Cones detect color and are concentrated in the fovea.

    • Rods are more sensitive to light and dark and are located in the peripheral retina.

  4. Color Vision Theories:

    • The trichromatic theory suggests we perceive color through three types of cones.

    • The opponent process theory explains afterimages and color pairings such as red-green and blue-yellow.

  5. Hearing Loss:

    • Conduction hearing loss occurs due to damage in the outer or middle ear.

    • Sensorineural hearing loss results from damage to the cochlea or auditory nerve.

  6. Sound localization helps us determine the location of a sound based on differences in time and intensity between ears.

  7. Olfactory System: Unlike other senses, smell information bypasses the thalamus and goes directly to brain areas involved in emotion and memory.

  8. Gustation (taste) includes five primary tastes: sweet, sour, salty, bitter, and umami.

  9. Gate Control Theory of Pain suggests that pain signals can be blocked by competing stimuli.

  10. Vestibular Sense relies on the inner ear to maintain balance and spatial orientation.

  11. Kinesthesis provides feedback about the position and movement of body parts.