Nervous System Flashcards
(20 cards)
Anatomy of the Nervous System
Central Nervous System (CNS):
- Brain (cerebrum, cerebellum, brainstem)
- Spinal cord
Peripheral Nervous System (PNS):
- Somatic nervous system (voluntary control)
- Autonomic nervous system (involuntary control)
Neuron Structure
Cell Body (Soma): Contains the nucleus and organelles.
Dendrites: Receive signals from other neurons.
Axon: Conducts impulses away from the cell body.
Myelin Sheath: Insulates the axon, speeding up signal transmission.
Axon Terminals: Release neurotransmitters to communicate with other neurons.
Types of Neurons
Sensory Neurons: Transmit sensory information to the CNS (afferent).
Motor Neurons: Send signals from the CNS to muscles and glands (efferent).
Interneurons: Connect sensory and motor neurons within the CNS; involved in reflexes.
Neurotransmitters
Definition: Chemicals that transmit signals across a synapse.
Examples:
- Acetylcholine: Involved in muscle contraction and memory.
- Dopamine: Affects mood, reward, and motor control.
- Serotonin: Regulates mood, appetite, and sleep.
- Norepinephrine: Involved in attention and responding actions.
Functions of the Central Nervous System
Integration Center: Processes sensory information and coordinates responses.
Higher Functions: Involved in cognition, memory, emotions, and decision-making.
Homeostasis: Regulates vital functions (e.g., heart rate, blood pressure).
Reflex Actions: Fast, automatic responses to stimuli.
Functions of the Peripheral Nervous System
Sensory Input: Gathers information from sensory receptors (e.g., skin, organs).
Motor Output: Transmits commands from the CNS to muscles and glands.
Autonomic Regulation: Controls involuntary functions (heart rate, digestion).
Somatic Control: Manages voluntary movements and reflexes.
Autonomic Nervous System
Divisions:
- Sympathetic Nervous System: Prepares the body for “fight or flight” response (increases heart rate, dilates pupils).
- Parasympathetic Nervous System: Promotes “rest and digest” functions (slows heart rate, stimulates digestion).
Balance: Maintains homeostasis through opposing actions.
Brain Anatomy
Cerebrum: Largest part; responsible for higher functions (thought, memory, movement).
Cerebellum: Coordinates voluntary movements, balance, and posture.
Brainstem: Controls vital functions (breathing, heart rate); consists of midbrain, pons, and medulla oblongata.
Limbic System: Involved in emotions, memories, and arousal.
Cerebrospinal Fluid (CSF)
Functions: Cushions the brain, removes waste, and provides buoyancy.
Production: Made in the ventricles of the brain; circulates around the CNS.
Clinical Significance: CSF analysis can diagnose infections, hemorrhages, and neurological disorders.
Meninges
Definition: Protective membranes covering the brain and spinal cord.
Layers:
Dura Mater: Tough outer layer.
Arachnoid Mater: Middle layer; contains cerebrospinal fluid (CSF).
Pia Mater: Delicate inner layer adhering to the brain and spinal cord.
Reflex Arc
Definition: Neural pathway that mediates a reflex action.
Components:
Receptor: Detects stimulus.
Sensory Neuron: Transmits impulse to CNS.
Integration Center: Processes information (usually in the spinal cord).
Motor Neuron: Sends impulse to effector.
Effector: Muscle or gland that responds.
Common Neurological Disorders
Stroke: Disruption of blood flow to the brain; leads to loss of function.
Multiple Sclerosis (MS): Autoimmune disorder affecting myelin in the CNS.
Parkinson’s Disease: Neurodegenerative disorder affecting movement and coordination.
Alzheimer’s Disease: Progressive cognitive decline; impacts memory and thinking.
Glasgow Coma Scale (GCS)
Purpose: Assess consciousness level in patients with head injury.
Components:
Eye Opening (1-4)
Verbal Response (1-5)
Motor Response (1-6)
Total Score: Ranges from 3 (deep coma) to 15 (fully alert).
Neurological Assessment
History Taking: Gather information about symptoms, duration, and onset.
Physical Exam: Assess cranial nerves, motor and sensory function, coordination, and reflexes.
Mental Status Exam: Evaluate orientation, memory, and cognitive function.
Cerebral Hemodynamics
Definition: Blood flow to the brain; crucial for oxygen and nutrient delivery.
Regulation: Autoregulation maintains constant blood flow despite changes in blood pressure.
Clinical Relevance: Impaired cerebral blood flow can lead to stroke and other neurological deficits.
Pain Pathways
Nociceptors: Specialized nerve endings that detect painful stimuli.
Transmission: Pain signals travel through peripheral nerves to the spinal cord and brain.
Modulation: Endogenous (natural) mechanisms and medications can alter pain perception.
Sleep and the Nervous System
Stages of Sleep: Non-REM (NREM) and REM sleep; essential for restoration and memory consolidation.
Circadian Rhythm: Regulated by the suprachiasmatic nucleus (SCN) in the hypothalamus.
Clinical Consideration: Sleep disorders (e.g., insomnia, sleep apnea) affect overall health and cognition.
Neuroplasticity
Definition: Brain’s ability to reorganize and adapt in response to experience and injury.
Types: Functional plasticity (one area takes over another’s function) and structural plasticity (changes in neural connections).
Clinical Relevance: Rehabilitation can enhance recovery following neurological damage.
Patient Education on Nervous System Health
Lifestyle Modifications: Importance of regular exercise, balanced diet, and stress management.
Cognitive Health: Engage in mental exercises and social activities to promote brain health.
Regular Check-ups: Monitor blood pressure, cholesterol, and diabetes to reduce stroke risk.
Emergency Neurological Interventions
Signs of Neurological Emergencies: Sudden headache, confusion, weakness, speech difficulty, seizures.
Initial Assessment: Check airway, breathing, circulation (ABCs).
Immediate Actions: Administer oxygen, monitor vital signs, and prepare for possible advanced interventions (e.g., CT scan, medication).
