Nuero Lecture Part 1

Overview of Adrenaline and Its Effect on the Body

  • Fight or Flight Response: Adrenaline triggers various physiological reactions essential for survival in stressful situations.

    • Increased Heart Rate: The heart pumps faster to circulate blood quickly.

    • Increased Respiratory Rate: Breathing rate rises to bring more oxygen into the lungs.

    • Goal: Oxygenated blood is delivered to muscles for immediate energy needs.

Physiological Blood Shunting

  • Blood Diversion Mechanism: During stress, blood is redirected to key organs.

    • Target Areas for Blood Supply:

    • Lungs: For oxygen exchange.

    • Muscles: To enhance physical response (fight or flight).

Types of Stress Responses

  • Real Stress: A physical threat, like an attacker.

  • Perceived Stress: Psychosocial stress, such as social rumors or emotional turmoil.

Parasympathetic Nervous System Activation

  • Rest and Digest: Triggered by acetylcholine, this system counteracts the fight or flight response.

    • Responses:

    1. Slowing Heart Rate: Body enters a relaxed state.

    2. Decreased Respiratory Rate: Breathing stabilizes to normal levels.

    3. Increased Blood Flow to GI Tract: Enhances digestion and nutrient absorption.

Sensory Organ Responses during Stress

  • Pupil Dilation: Increases light entry to enhance vision under stress.

  • Acute Hearing: Sensory perception heightens to detect threats more effectively.

Pain Sensation Alteration

  • Diminished Pain Sensation: Body tolerates pain better in high-stress situations, focusing on survival.

Autonomic Nervous System Structure

  • Components:

    1. Sympathetic Nervous System: Activates fight or flight.

    2. Parasympathetic Nervous System: Governs rest and digest.

    • Communication: Managed via central nervous system pathways.

Sensory and Motor Systems

  • Sensory Nervous System: Transmits sensory information to the brain (afferent pathway).

  • Motor Nervous System: Communicates commands from the brain to muscles (efferent pathway).

Reflex Arcs and Proprioception

  • Reflex Arcs: Automatic responses bypassing conscious thought.

    • Example: Touching a hot surface and retracting hand quickly.

Myelin Sheath Importance

  • Myelin Sheath Function: Insulates axons to speed up neural transmission.

    • Demyelinating Diseases: Eg. Multiple Sclerosis (MS) leads to slower responses as myelin is damaged.

Neurotransmitters and their Roles

  1. Dopamine: Reward neurotransmitter, depletion linked to Parkinson's Disease.

  2. Serotonin: Regulates mood and happiness, targeted by SSRIs to alleviate depression.

  3. Acetylcholine: Involved in memory and motor control, impacts muscle movements and autonomic functions.

  4. Endorphins: Pain relief neurotransmitters, releasing in response to trauma to mitigate pain.

  5. Oxytocin: Facilitates bonding, particularly in maternal contexts.

  6. GABA: Calms nervous system, counteracting excitatory neurotransmitters.

  7. Cortisol: Stress hormone, essential in the bodily response to danger but harmful in excess.

  8. Endocannabinoids: Modulate neurotransmitter release, linking to THC from cannabis.

Nervous System Cranial Nerves Overview

  • Cranial Nerves Count: 12 cranial nerves, each with specific functions.

  1. I - Olfactory: Sensation of smell.

  2. II - Optic: Vision.

  3. III - Oculomotor: Eye movement.

  4. IV - Trochlear: Eye movement (downward).

  5. V - Trigeminal: Facial sensation and chewing muscles.

  6. VI - Abducens: Eye movement (laterally).

  7. VII - Facial: Facial expressions, taste on anterior 2/3 of tongue.

  8. VIII - Vestibulocochlear: Hearing and balance.

  9. IX - Glossopharyngeal: Taste on posterior 1/3 of tongue, gag reflex.

  10. X - Vagus: Autonomic control of heart and digestive tract functions.

  11. XI - Accessory: Shoulder movement and head rotation.

  12. XII - Hypoglossal: Tongue movements.

Brain Structure Overview

  1. Brain Stem: Controls basic life functions (heart rate, breathing).

  2. Cerebellum: Responsible for balance and coordination.

  3. Limbic System: Emotion and motivation regulation (thalamus, amygdala, hypothalamus).

  4. Cerebrum: Higher brain functions, reasoning, and decision-making.

Clinical Considerations of the Nervous System

  • Glasgow Coma Scale: Assesses a patient's level of consciousness.

  • Reflex Testing: Assesses nervous system integrity; absent or exaggerated responses indicate neuro dysfunction.

  • Neurological Diseases: Understand the implications of diseases such as MS, Parkinson's, and AIDS on the nervous system.

Aging and Nervous System Effects

  • Geriatric Considerations: Recognize normal aging symptoms versus abnormal symptoms indicative of neurological diseases (e.g., dementia, delirium).

    • Memory Issues: Short-term memory may decline, indicating dementia if major impairments occur.

    • Communication Difficulties: Important to tailor communication techniques for patients with cognitive decline.

Diagnostics in Neurology

  • Lumbar Puncture: To test for meningitis or other neurological infections.

  • Electroencephalogram (EEG): Measures the electrical activity of the brain to diagnose seizure disorders or sleep patterns.

  • Carotid Artery Duplex Scan: Assesses blood flow and plaque buildup, evaluating risks for stroke.

Alzheimer’s Disease Overview

  • Characteristic Features: Neurofibrillary tangles and neuritic plaques detectable post-mortem. Diagnosis primarily through symptoms.

  • Medications: Cholinesterase inhibitors to slow progression, but no cure exists.

  • Family Impact: Genetic predisposition noted in familial cases.

Parkinson’s Disease Overview

  • Symptoms: Resting tremors, rigidity, slowness, and postural instability.

  • Treatment: Primarily dopamine replacement therapy (Carbidopa/Levodopa) and management of symptoms.

  • Michael J. Fox's Advocacy: Highlights the personal impact and the need for research into the disease.

Seizure Definition and Classification

  • Seizures as Symptoms: Differ from epilepsy, which is a chronic condition rather than an isolated incident.

  • Types of Seizures:

    1. Partial (Focal): Affect one hemisphere, often mild and without complete loss of consciousness.

    2. Generalized: Affect both hemispheres, with loss of consciousness, possible incontinence, or thrashing.

  • Postictal Phase: Recovery phase post-seizure with confusion and lethargy.

Management of Seizures

  • Immediate Care: Protect head, clear the area, do not restrain, ensure airway is clear.

  • Medication: Benzodiazepines (e.g., Ativan, Valium) used for acute seizure management.

  • Education: Inform caregivers about triggers, safety measures, and potential medication interactions.