Nervous System Overview

Peripheral Nervous System (PNS) vs. Central Nervous System (CNS)

The nervous system is divided into two main parts: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS). Each has distinct structures and functions.

• Central Nervous System (CNS): Consists of the brain and spinal cord. Responsible for processing and integrating information, and directing responses.

• Peripheral Nervous System (PNS): Composed of all nerves outside the CNS. Connects the CNS to limbs and organs, serving as a communication relay.

Example: Sensory information from the skin travels via the PNS to the CNS for processing.

Brain Structure and Terminology

Major Brain Regions and Terms

• Sulcus (plural: sulci): A groove or furrow on the brain's surface, separating gyri.

• Gyrus (plural: gyri): A ridge on the cerebral cortex, surrounded by sulci.

• Fissure: A deep groove in the brain, such as the longitudinal fissure separating the two hemispheres.

Protective Structures

• Arachnoid, Pia, and Dura Mater: The three meninges (protective membranes) covering the brain and spinal cord.

• Dura mater: Outermost, tough layer.

• Arachnoid mater: Middle, web-like layer.

• Pia mater: Innermost, delicate layer adhering to the brain surface.

Neural Reflexes and Pathways

Knee Jerk Reflex

The knee jerk reflex is a classic example of a monosynaptic reflex arc, involving a direct communication between sensory and motor neurons.

• Effector: Muscle or gland that responds to neural input.

• Receptor: Structure that detects a stimulus.

• Afferent neuron: Carries sensory information to the CNS.

• Efferent neuron: Carries motor commands from the CNS to effectors.

• Integration center: Processes information in the CNS.

Sequence: Receptor → Afferent neuron → Integration center → Efferent neuron → Effector

Other Neural Terms

• Nociceptors: Sensory receptors that detect pain.

• Sciatica: Pain along the sciatic nerve, often due to compression or irritation.

• Vagus nerve: A cranial nerve that controls parasympathetic output to many organs.

• "Funny bone" nerve: The ulnar nerve, which when struck causes tingling in the forearm and hand.

States of Consciousness and Brain Function

REM Sleep and Coma

• REM Sleep: Rapid Eye Movement sleep, a stage of sleep characterized by vivid dreams and muscle atonia.

• Coma: A state of deep unconsciousness from which a person cannot be awakened.

• Syncope: Temporary loss of consciousness (fainting) due to reduced blood flow to the brain.

Brain Regions and Their Functions

Major Brain Structures

• Temporal lobe: Involved in auditory processing and memory.

• Occipital lobe: Responsible for visual processing.

• Cerebellum: Coordinates voluntary movements and balance.

• Hypothalamus: Regulates homeostasis, including temperature, hunger, and hormone release.

• Hippocampus: Essential for memory formation.

• Prefrontal cortex: Involved in decision-making, planning, and social behavior.

• Limbic system: A group of structures involved in emotion, motivation, and memory.

Autonomic Nervous System (ANS)

Sympathetic vs. Parasympathetic Nervous System

The Autonomic Nervous System regulates involuntary body functions and is divided into the Sympathetic Nervous System (SNS) and Parasympathetic Nervous System (PNS).

• Sympathetic Nervous System (SNS): Prepares the body for "fight or flight" responses.

• Parasympathetic Nervous System (PNS): Promotes "rest and digest" activities.

Comparison Table: Effects of SNS and PNS

Parasympathetic Effects on Organs/Systems

• Heart: Slows heart rate.

• Lungs: Constricts bronchi.

• Brain: Promotes calm and restorative processes.

• Digestive system: Stimulates digestion and peristalsis.

• Salivary glands: Increases saliva production.

• Pupils: Constricts pupils.

• Skeletal muscles: Minimal direct effect.

• Blood pressure: Lowers blood pressure.

Short Answer/Essay Concepts

Comparing SNS and PNS Effects

• Describe at least 5 different signs that a patient's fight or flight mode is stimulated (e.g., increased heart rate, dilated pupils, dry mouth, sweating, decreased digestive activity).

• Explain physiological causes of symptoms like "butterflies in the stomach" (e.g., SNS reduces blood flow to the digestive tract during stress).

Study and Memory Strategies

• Use anatomical and physiological terms to describe methods for improving study and recall (e.g., spaced repetition, active recall, association with brain regions like the hippocampus).

• Examples: Creating concept maps, teaching material to others, and practicing retrieval of information.

Key Definitions and Concepts

• Effector: An organ or cell that acts in response to a stimulus.

• Receptor: A structure that detects changes in the environment.

• Afferent neuron: Transmits sensory signals to the CNS.

• Efferent neuron: Transmits motor signals from the CNS to effectors.

• Integration center: CNS region that processes incoming information.

Sequence of a Reflex Arc:

• Receptor → Afferent neuron → Integration center → Efferent neuron → Effector

Additional info: The study notes above expand on the brief terms and questions provided, offering definitions, examples, and context for each concept relevant to a college-level Anatomy & Physiology course.