Nervous System Mcat

a) Central and peripheral nervous systems

Content Category 3A: Structure and functions of the nervous and endocrine systems and ways in which these systems coordinate the organ systems

The nervous and endocrine systems work together to detect external and internal signals, transmit and integrate information, and maintain homeostasis. They do all of this by producing appropriate responses to internal and external cues and stressors. The integration of these systems both with one another, and with the other organ systems, ultimately results in the successful and adaptive behaviors that allow for the propagation of the species.

Animals have evolved a nervous system that senses and processes internal and external information that is used to facilitate and enhance survival, growth, and reproduction. The nervous system interfaces with sensory and internal body systems to coordinate physiological and behavioral responses ranging from simple movements and small metabolic changes to long-distance migrations and social interactions. The physiological processes for nerve signal generation and propagation involve specialized membranes with associated proteins that respond to ligands and/or electrical field changes, signaling molecules and, by extension, the establishment and replenishment of ionic electrochemical gradients requiring ATP.

The endocrine system of animals has evolved to produce chemical signals that function internally to regulate stress responses, reproduction, development, energy metabolism, growth, and various individual and interactive behaviors. The integrated contributions of the nervous and endocrine systems to bodily functions are exemplified by the process whereby the signaling of neurons regulates hormone release, and by the targeting of membrane or nuclear receptors on neurons by circulating hormones.

The content in this category covers the structure, function, and basic aspects of nervous and endocrine systems, and their integration. The structure and function of nerve cells is also included in this category.

• Major Functions
  • High level control and integration of body systems
  • Adaptive capability to external influences
  • Feedback loop, reflex arc
  • Role of spinal cord and supraspinal circuits
  • Ch. 7 The Nervous System and Neuronal Excitability, pp. 191-193
  • Ch. 10 Autonomic and Somatic Nervous Systems
  • Ch. 4 The Structure and Function of the Plasma Membrane, pp. 158-167
  • Cell body: site of nucleus, organelles
  • Dendrites: branched extensions of cell body
  • Axon: structure and function
  • Myelin sheath, Schwann cells, insulation of axon
  • Nodes of Ranvier: propagation of nerve impulse along axon
  • Synapse: site of impulse propagation between cells
  • Synaptic activity: transmitter molecules
  • Resting potential: electrochemical gradient
  • Action potential
    • Threshold, all-or-none
    • Sodium/potassium pump
    • 35.1 Neurons and Glial Cell
    • Ch. 7 The Nervous System and Neuronal Excitability, pp. 193-223
    • Ch. 4 The Structure and Function of the Plasma Membrane, pp. 118-119, 158-167
    • Gated ion channels
      • Voltage gated
      • Ligand gated
      • Ch. 13 Membrane Channels and Pumps, pp. 403-431
      • Ch. 14 Signal-Transduction Pathways, pp. 437-459
      • Ch. 12 Membrane Structure and Function, pp. 231-239
      • Ch. 13 Signal-Transduction Pathways, pp. 245-261
      • 9.1 Signaling Molecules and Cellular Receptors
      • 9.2 Propagation of the Signal
      • Ch. 13 Biochemical Signaling, pp. 402-441
      • Ch. 6 Cell Signaling, pp. 169-185
      • Ch. 7 The Nervous System and Neuronal Excitability, pp. 201-202
      • Ch. 4 The Structure and Function of the Plasma Membrane, pp. 143-151
      • Ch. 15 Cell Signaling and Cell Transduction: Communication Between Cells pp. 582-598
      • Description; structure
        • Steroids
        • Terpenes and terpenoids
        • Ch. 26 The Biosynthesis of Membrane Lipids and Steroids, pp. 858-882
        • Ch. 29 Lipid Synthesis: Storage Lipids, Phospholipids and Cholesterol, pp. 577-601
        • 3.3 Lipids
        • Ch. 9 Lipids and Biological Membranes, pp. 245-292
        • Ch. 2 Chemical Composition of the Body, pp. 40-45
        • Ch. 2 The Chemical Basis of Life, pp. 46-49
        • Function of endocrine system: specific chemical control at cell, tissue, and organ level
        • Definitions of endocrine gland, hormone
        • Major endocrine glands: names, locations, products
        • Major types of hormones
        • Neuroendrocrinology ― relation between neurons and hormonal systems
        • 37.1 Types of Hormones
        • 37.2 How Hormones Work
        • 37.5 Endocrine Glands
        • Ch. 13 The Endocrine System, pp. 448-456
        • Cellular mechanisms of hormone action
        • Transport of hormones: blood supply
        • Specificity of hormones: target tissue
        • Integration with nervous system: feedback control regulation by second messengers
        • 37.3 Regulation of Body Processes
        • Ch. 22 Mammalian Fuel Metabolism: Integration and Regulation: Section 2. Hormonal Control of Fuel Metabolism, pp. 781-785
        • Ch. 13 The Endocrine System, pp. 448-456
        • Ch. 15 Cell Signaling and Cell Transduction: Communication Between Cells, pp. 583-586, 599-602

        Nervous System for the MCAT: Everything You Need to Know

        Learn key MCAT concepts about the nervous system, plus practice questions and answers

        

        (Note: This guide is part of our MCAT Biology series.)

        Table of Contents

        Part 1: Introduction to the nervous system

        Part 2: Divisions of the nervous system

        a) Central and peripheral nervous systems

        b) Autonomic and somatic nervous systems

        c) Sympathetic and parasympathetic nervous systems

        Part 3: Microanatomy

        a) Anatomy of a neuron

        b) Cells of the nervous system

        c) The action potential

        d) Neural impulses and neurotransmitters

        Part 4: Types of neurons

        a) Afferent and efferent neurons

        b) Upper and lower motor neurons

        Part 5: High-yield terms

        Part 6: Passage-based questions and answers

        Part 7: Standalone questions and answers

        Part 1: Introduction to the nervous system

        From allowing you to perceive your surroundings to remembering your life’s most memorable moments, the nervous system can perform some of the most marvelous feats of any organ system. Unfortunately, studies show that many neurological disorders are on the rise. The incidence of Alzheimer’s disease, for example, is expected to triple by 2050. Thus, it is more vital than ever that the physicians of tomorrow are equipped with the knowledge needed to care for this growing group of patients.

        The information presented in this guide will describe key aspects of the nervous system that are relevant to biology and biochemistry. To better understand the function of the nervous system, be sure to refer to our Psychology and Sociology guides on Psychological Disorders and Behavior and Biology.

        Throughout this guide, you will see several terms in bold. Be sure to understand these concepts well! At the end of the guide, there will also be several MCAT-style practice problems you can use to test your knowledge.

        Let’s get started!

        Part 2: Divisions of the nervous system

        The nervous system is responsible for a variety of functions. Its primary function is to provide control between different body systems. The nervous system serves to integrate information from a variety of body systems, including information about the external environment that is carried into the body, and to coordinate responses that maintain internal homeostasis and proper cellular function.

        a) Central and peripheral nervous systems

        The nervous system can be divided into two major components. The brain and spinal cord comprise the central nervous system, while nerves and ganglia outside the brain and spinal cord make up the peripheral nervous system.

        The outermost part of the brain is the cerebral cortex. This layer merits special attention because it is responsible for many of our higher cognitive functions. The cerebral cortex is rich in the cell bodies, or soma, of neurons. These neurons have long axons that extend through the brain and into the spinal cord.

        The cerebral cortex can itself be divided into four major lobes, each with loosely specialized functions.

        • The frontal lobe governs executive function, initiates voluntary motor movement, and is responsible for producing speech.
        • The parietal lobe governs spatial processing, proprioception, and somatosensation.
        • The occipital lobe governs visual processing.

        The temporal lobe governs learning, memory, speech perception, and auditory perception. An important language center known as Wernicke’s area is located here.

        

        Each hemisphere, or side, of the brain is also loosely specialized. The left side of the brain processes sensory information from the right side of the body and is also the primary hemisphere used in performing math and science problems, logical reasoning, and analytical thinking. The right hemisphere of the brain processes sensory information from the left side of the body and is also the primary hemisphere used in spatial awareness, emotional intelligence, intuition, and holistic thinking.

        How do these two hemispheres communicate with each other? A structure called the corpus callosum forms a bridge between the left and right hemispheres of the brain. The nerves within the corpus callosum allow sensory information from one side to “cross” to the opposite hemisphere, where it can be processed. Thus, any environmental cues that are sensed by the right side of the body are sent to the left hemisphere of the brain for processing, and vice versa.