TORTORS NERVOUS

• What is the main objective of both the nervous and endocrine systems?

  To keep controlled conditions within limits that maintain life.
• How does the nervous system regulate body activities?


  By responding rapidly using nerve impulses.
• What does the endocrine system respond with?

  By releasing hormones.
• What are the main focuses of Chapter 12 regarding the nervous system?

  • Organization of the nervous system
  • Properties of neurons and neuroglia
  • Structure and functions of the spinal cord and spinal nerves
  • Structure and functions of the brain and cranial nerves
• What is the autonomic nervous system responsible for?


  It operates without voluntary control.
• What are the three basic functions of the nervous system?

  1. Sensory (input)
  2. Integrative (process)
  3. Motor (output)
• What is the sensory function of the nervous system?

  Sensory receptors detect internal and external stimuli.
• What does the integrative function of the nervous system do?

  It processes sensory information and makes decisions for appropriate responses.
• What is the motor function of the nervous system?

  It elicits an appropriate motor response by activating effectors.
• How does the nervous system demonstrate its functions when answering a cell phone?

  It detects the ringing (sensory), processes the information (integrative), and activates muscles to answer (motor).
• What are the two main subdivisions of the nervous system?

  1. Central Nervous System (CNS)
  2. Peripheral Nervous System (PNS)
• What does the central nervous system consist of?

  The brain and spinal cord.
• What is the role of the peripheral nervous system?


  It consists of all nervous tissue outside the CNS.
• How many pairs of cranial nerves emerge from the brain?

  Twelve pairs.
• How many pairs of spinal nerves emerge from the spinal cord?

  Thirty-one pairs.
• What is a sensory receptor?

  A structure that monitors changes in the external or internal environment.
• What does the sensory division of the PNS do?

  It conveys input into the CNS from sensory receptors.
• What types of sensations does the sensory division provide information about?

  Somatic senses and special senses.
• What is the basic structure of a neuron?

  It consists of a cell body, dendrites, and an axon.
• What is the function of dendrites in a neuron?

  They are the receiving or input portions of a neuron.
• What is the role of the axon in a neuron?

  It propagates nerve impulses toward another neuron, muscle fiber, or gland cell.
• What is the trigger zone in a neuron?

  It is the area where nerve impulses arise at the junction of the axon hillock and the initial segment.
• What is the axoplasm?


  It is the cytoplasm of an axon.
• What is the function of neuroglia?


  They support, nourish, and protect neurons.
• How do neurons differ from neuroglia in terms of division?

  Neurons have lost the ability to undergo mitotic divisions, while neuroglia continue to divide throughout life.
• What are the histological characteristics of neurons and neuroglia?

  • Neurons: specialized cells capable of reaching great lengths, lost ability to divide.
  • Neuroglia: smaller cells, outnumber neurons, support and protect neurons, continue to divide.
• What is electrical excitability in neurons?

  It is the ability to respond to a stimulus and convert it into an action potential.
• What initiates an action potential in a neuron?

  A stimulus that is strong enough to initiate it.
• What is the role of ions in the generation of an action potential?

  They move between interstitial fluid and the inside of the neuron.
• What is the term for a collection of neuron cell bodies outside the CNS?

  A ganglion.
• What is lipofuscin in aging neurons?

  It is a pigment that accumulates as clumps of yellowish brown granules in the cytoplasm.
• What is the function of Nissl bodies in neurons?

  They are sites of protein synthesis used to replace cellular components and regenerate damaged axons.
• What are neurofibrils and microtubules in the cytoskeleton of neurons?

  Neurofibrils provide cell shape and support, while microtubules assist in moving materials between the cell body and axon.
• What is the mass of the nervous system in relation to total body weight?

  About 3% of total body weight.
• What is the role of the central nervous system in processing sensory information?

  It processes many different kinds of incoming sensory information.
• What is the source of thoughts, emotions, and memories in the body?

  The central nervous system.
• What is the function of the peripheral nervous system in relation to the CNS?

  It conveys sensory information to the CNS and motor commands from the CNS to the body.
• What is the significance of the axon hillock in a neuron?

  It is where nerve impulses arise before traveling along the axon.
• What is the initial segment of an axon?

  It is the part of the axon closest to the axon hillock.
• What is the role of the axolemma?

  It is the plasma membrane that surrounds the axoplasm.