Muscle and Nerve Lec

• Muscle tissue


  Responsible for movement, maintenance of posture, respiration, production of body heat, communication, constriction of organs and vessels, contraction of the heart
• Types of muscle tissue

  • Skeletal muscle
  • Cardiac muscle
  • Smooth muscle
• Skeletal muscle structure


  • Epimysium
  • Perimysium
  • Endomysium
• Sarcomere


  Fundamental unit of skeletal muscle
• Types of filaments in sarcomere

  • Myosin
  • Actin
• Skeletal muscle sensory receptors

  • Muscle spindle (stretch detectors)
  • Tendon (Golgi) organs (detect changes in tension)
• Types of skeletal muscle fibers

  • Type I (slow, red oxidative)
  • Type IIa (fast, intermediate oxidation-glycolytic)
  • Type IIb (fast, white glycolytic)
• Cardiac muscle


  • Intercalated discs
• Smooth muscle


  • Involuntary, found in walls of organs and blood vessels
• Divisions of the nervous system

  • Central nervous system
  • Peripheral nervous system
• Irritability vs Conductivity


  Ability to respond to stimuli vs ability to transmit impulses
• Grey matter vs White matter

  Grey matter contains neuron cell bodies, white matter contains myelinated axons
• Neuron


  • Cell body, dendrites, axon
• Types of neurons by structure

  • Unipolar
  • Pseudounipolar
  • Bipolar
  • Multipolar
• Ependymal cells


  Line the central canal of spinal cord and ventricular cavities of the brain
• Astrocytes


  • Most numerous glial cells, provide support and protection for neurons
• Oligodendrocytes


  • Produce the myelin sheath in the CNS
• Microglia


  • Act as phagocytes, provide immune-related activity in the CNS
• Cerebrum


  • Largest part of the brain, responsible for higher cognitive functions
• Cerebellum


  • Coordinates voluntary movements and maintains posture and balance
• Spinal cord


  • Connects the brain to the peripheral nervous system, contains grey matter and white matter
• Meninges


  • Protective membranes surrounding the brain and spinal cord
• Blood-brain barrier


  Protects the brain from toxins and infectious agents
• Choroid plexus


  • Specialized tissue that produces cerebrospinal fluid
• Cerebrospinal fluid


  Clear, low-density fluid that circulates through the ventricles, central canal, and subarachnoid space
• Peripheral nervous system


  • Consists of nerves, ganglia, and nerve endings
• Schwann cells


  • Form myelin sheath around axons in the PNS
• Satellite cells


  • Form a covering layer over neuron cell bodies in PNS ganglia
• Myelinated nerve fiber


  • Axons covered by myelin sheath, with nodes of Ranvier between adjacent Schwann cells
• Unmyelinated nerve fiber


  • Axons without myelin sheath, enveloped within Schwann cell folds
• Nerve structure


  • Epineurium, perineurium, endoneurium
• Ganglia


  • Aggregations of nerve cell bodies outside the CNS
• Types of ganglia


  • Cranio-spinal ganglia
  • Autonomic ganglia
• Cranio-spinal ganglia


  • Sensory ganglia, receive afferent impulses to the CNS
• Autonomic ganglia


  • Visceral motor ganglia, consist of sympathetic and parasympathetic ganglia
• Nerves can regenerate after injury
• What is the connetive tissue of dura mater?

  Dense irregular connective tissue
• A large sponge- like cavity, filled with CSF. This fluid-filled space helps cushion and protect the CNS from minor trauma

  Subarachnoid space
• The connective tissue of arachnoid is said to be ____

  avascular