peripheral nervous system

Examples of peripheral nervous system in the following topics:

• The Nervous System

  • The nervous system is composed of the central nervous system (brain and spinal cord) and the peripheral nervous system (nerves).
  • A classification of the nervous system can be performed under different aspects.
  • Two major divisions of the nervous system are the central nervous system (CNS) and the peripheral nervous system (PNS).
  • The peripheral nervous system consists of nerves that are connected to the brain (cranial nerves) and nerves that are connected to the spinal cord (spinal nerves).
  • The autonomic nervous system, also part of the peripheral nervous system, controls internal body functions that are not under conscious control.

• Neurons and Glial Cells

  • In most types of vertebrate animals, it consists of two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS).
  • The PNS includes motor neurons (mediating voluntary movement), the autonomic nervous system (comprising the sympathetic nervous system and the parasympathetic nervous system, which regulate involuntary functions), and the enteric nervous system (a semi-independent part of the nervous system whose function is to control the gastrointestinal system).
  • Flatworms of the phylum Platyhelminthes have both a central nervous system, made up of a small "brain" and two nerve cords, and a peripheral nervous system containing a system of nerves that extend throughout the body.
  • In (f) vertebrates, the brain and spinal cord comprise the central nervous system, while neurons extending into the rest of the body comprise the peripheral nervous system.
  • Recall the differences in structure and function between the central and peripheral nervous systems

• Glia

  • While glia (or glial cells) are often thought of as the supporting cast of the nervous system, the number of glial cells in the brain actually outnumbers the number of neurons by a factor of ten.
  • Glial cells of the (a) central nervous system include oligodendrocytes, astrocytes, ependymal cells, and microglial cells.
  • Glial cells of the (b) peripheral nervous system include Schwann cells, which form the myelin sheath, and satellite cells, which provide nutrients and structural support to neurons.
  • (a) Astrocytes and (b) oligodendrocytes are glial cells of the central nervous system.
  • Describe the specific roles that the seven types of glia play in the nervous systems

• Spinal Cord

  • The spinal cord is contained within the bones of the vertebral column, but is able to communicate signals to and from the body through its connections with spinal nerves (part of the peripheral nervous system).

• Structure and Function of the Muscular System

  • The muscular system is closely associated with the skeletal system in facilitating movement.
  • Both voluntary and involuntary muscular system functions are controlled by the nervous system.
  • Morphologically skeletal myocytes are elongated and tubular and appear striated with multiple peripheral nuclei.
  • Smooth muscle tissue is associated with numerous organs and tissue systems, such as the digestive system and respiratory system.
  • Skeletal muscle of the muscular system is closely associated with the skeletal system and acts to maintain posture and control voluntary movement.

• Autonomic Nervous System

  • The autonomic nervous system, the relay between the CNS and internal organs, is divided into the sympathetic and parasympathetic systems.
  • The autonomic nervous system (ANS) serves as the relay between the central nervous system (CNS) and the internal organs.
  • There are two divisions of the autonomic nervous system that often have opposing effects: the sympathetic nervous system and the parasympathetic nervous system .
  • While the sympathetic nervous system is activated in stressful situations, the parasympathetic nervous system allows an animal to "rest and digest."
  • In the autonomic nervous system, a preganglionic neuron of the CNS synapses with a postganglionic neuron of the parasympathetic nervous system.

• Sensory-Somatic Nervous System

  • The sensory-somatic nervous system transmits sensory information from the body to the brain and motor movements from the brain to the body.
  • The sensory-somatic nervous system is composed of cranial and spinal nerves and contains both sensory and motor neurons.
  • Sensory neurons transmit sensory information from the skin, skeletal muscle, and sensory organs to the central nervous system (CNS).
  • Without its sensory-somatic nervous system, an animal would be unable to process any information about its environment (what it sees, feels, hears, etc. ) and could not control motor movements.
  • Explain the role of the cranial and spinal nerves in the sensory-somatic nervous system

• Muscle Tissues and Nervous Tissues

  • The walls of blood vessels, the tubes of the digestive system, and the tubes of the reproductive systems are composed primarily of smooth muscle.
  • Skeletal muscle is under voluntary, somatic nervous system control and is found in the muscles that move bones.
  • Cardiac muscle is not under voluntary control, but is influenced by the autonomic nervous system to speed up or slow down the heart beat.
  • The main cell of the nervous system is the neuron.
  • Describe the structure and function of nervous tissue; differentiate among the types of muscle tissue

• Epinephrine and Norepinephrine

  • An increase in norepinephrine from the sympathetic nervous system increases the rate of contractions in the heart.
  • It is also a neurotransmitter in the central nervous system and sympathetic nervous system, where it is released from noradrenergic neurons in the locus coeruleus.
  • Epinephrine and norepinephrine are released by the adrenal medulla and nervous system respectively.
  • These hormones go one step further and trigger the renin-angiotensin-aldosterone system, the hormone system that regulates blood pressure and water (fluid) imbalance.

• Other Neurological Disorders

  • Epilepsy and stroke are examples of neurological disorders that arise from malfunctions in the nervous system.
  • These include chronic pain conditions, cancers of the nervous system, epilepsy disorders, and stroke.