المحاضرة الخامسة فسيو (بعد التعديل)
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المحاضرة الخامسة فسيو (بعد التعديل)

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Questions and Answers

What is the primary function of the sympathetic division of the autonomic nervous system?

  • To regulate digestive functions
  • To promote repair and recovery
  • To prepare the body for activity (correct)
  • To preserve energy in the body

    • Which neurotransmitter is commonly released by postganglionic neurons in the sympathetic nervous system?

  • Noradrenaline (correct)
  • GABA
  • Dopamine
  • Serotonin

    • What is the primary role of the parasympathetic division during rest?

  • Promoting energy expenditure
  • Increasing heart rate
  • Dilating pupils
  • Allowing repair and recovery (correct)

    • How does sympathetic mass stimulation affect the body?

    <p>It can have generalized effects</p> Signup and view all the answers

    What ratio of preganglionic fibers to postganglionic fibers is associated with the sympathetic nervous system?

    <p>1:32</p> Signup and view all the answers

    What type of myelination do sympathetic preganglionic neurons have?

    <p>Thin myelinated</p> Signup and view all the answers

    What characterizes the function of autonomic ganglia?

    <p>They serve as a relay and distribution center</p> Signup and view all the answers

    What type of fibers are postganglionic neurons in the autonomic nervous system?

    <p>Non-myelinated</p> Signup and view all the answers

    What is the ratio of preganglionic fibers to postganglionic fibers in the parasympathetic nervous system?

    <p>1:2</p> Signup and view all the answers

    Which of the following ganglia lie closely related to the aorta and its branches?

    <p>Collateral ganglia</p> Signup and view all the answers

    Which type of ganglia is interconnected by nerve fibers and located on both sides of the spinal cord?

    <p>Lateral ganglia</p> Signup and view all the answers

    What is the main characteristic of sympathetic postganglionic fibers?

    <p>They are longer than preganglionic fibers.</p> Signup and view all the answers

    Which ganglion is NOT associated with the autonomic nervous system?

    <p>Dorsal root ganglion</p> Signup and view all the answers

    Which of the following statements is true regarding the adrenal medulla?

    <p>It is the only sympathetic effector organ directly innervated by preganglionic fibers.</p> Signup and view all the answers

    What type of fibers are present in the parasympathetic nervous system?

    <p>Long preganglionic and short postganglionic.</p> Signup and view all the answers

    Which characteristic is true for the sympathetic nervous system?

    <p>It delays fatigue of the contracting muscles.</p> Signup and view all the answers

    What is a key function of the parasympathetic?

    <p>Promoting repair and recovery during rest.</p> Signup and view all the answers

    What type of chemical transmitter is released by postganglionic neurons of the sympathetic nervous system?

    <p>Noradrenaline</p> Signup and view all the answers

    What is the myelination type of postganglionic neurons in the autonomic nervous system?

    <p>Non-myelinated</p> Signup and view all the answers

    Which of the following roles does the sympathetic nervous system primarily serve?

    <p>Preparing the body for intense physical activity.</p> Signup and view all the answers

    What is the primary difference in the effects of sympathetic and parasympathetic mass stimulation?

    <p>Sympathetic mass stimulation can be useful, while parasympathetic may be fatal.</p> Signup and view all the answers

    What best describes the 'Fight or Flight' response associated with the sympathetic nervous system?

    <p>Increasing energy expenditure and readiness for action.</p> Signup and view all the answers

    What is a characteristic of collateral (pre-vertebral) ganglia in terms of their location?

    <p>They are located midway between the spinal cord and viscera</p> Signup and view all the answers

    Which statement accurately describes the structure of terminal ganglia?

    <p>They have long preganglionic and short postganglionic fibers</p> Signup and view all the answers

    Which of the following is a distinguishing feature of the sympathetic nervous system compared to the parasympathetic system?

    <p>Preganglionic fibers in the sympathetic system are short</p> Signup and view all the answers

    What is unique about the adrenal medulla in regards to sympathetic innervation?

    <p>It is the only organ directly innervated by preganglionic nerve fibers</p> Signup and view all the answers

    How does the ratio of preganglionic to postganglionic fibers in the parasympathetic system compare to that in the sympathetic system?

    <p>Parasympathetic fibers have a ratio of 1:2</p> Signup and view all the answers

    Which type of fibers are associated with the lateral (para-vertebral) ganglia?

    <p>Short preganglionic and long postganglionic fibers</p> Signup and view all the answers

    Which ganglia are NOT typically associated with the sympathetic nervous system?

    <p>Terminal ganglia</p> Signup and view all the answers

    What is the effect of having a 1:2 ratio of preganglionic to postganglionic fibers in the parasympathetic nervous system?

    <p>It results in more localized effects</p> Signup and view all the answers

    Study Notes

    Autonomic Nervous System (ANS)

    • The ANS regulates involuntary or visceral functions in the body.
    • Divided into two branches: Sympathetic & Parasympathetic.
    • Sympathetic: "Fight or Flight"
    • Prepares the body for activity, increasing capacity for effort in response to stress.
    • Delays onset of fatigue in contracting muscles.
    • Mass stimulation is useful.
    • Increases energy expenditure.
    • Catabolic to energy.
    • Parasympathetic: "Rest and Digest"
      • Predominates during rest and sleep.
      • Allows for repair and recovery of contracting muscles.
      • Mass stimulation may be fatal.
      • Preserves energy in the body.
      • Anabolic to energy.

    Course of the ANS

    • Composed of Preganglionic & Postganglionic neurons
    • Preganglionic neurons originate inside the CNS
    • Postganglionic neurons originate outside the CNS in autonomic ganglia.
    • Both types end at effector organs.
    • Preganglionic neurons:
      • Thin and myelinated (type B).
      • Fewer in number.
      • Use acetylcholine (Ach) as a neurotransmitter.
    • Postganglionic neurons:
      • Non-myelinated (type C).
      • More numerous
      • Use Ach or noradrenaline as a neurotransmitter.

    Autonomic Ganglia

    • Collections of cell bodies of neurons outside the CNS.
    • Functions:
      • Relay station for autonomic preganglionic nerve fibers.
      • Distributing center.
        • Sympathetic:
          • Ratio of preganglionic to postganglionic fibers is 1:32.
          • Has generalized effects.
        • Parasympathetic:
          • Ratio of preganglionic to postganglionic fibers is 1:2.
          • Has localized effects.
    • Adrenal Medulla: The only sympathetic effector organ directly innervated by preganglionic nerve fibers.

    Types of Ganglia

    • Lateral (Para-Vertebral)
      • Located on both sides of the spinal cord.
      • Interconnected by nerve fibers, forming the sympathetic chain.
      • Short preganglionic and long postganglionic fibers.
      • Classified according to spinal segment: 3 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal.
    • Collateral (Pre-Vertebral)
      • Located mainly in the abdomen, midway between the spinal cord and viscera.
      • Preganglionic fibers are equal in length to postganglionic fibers.
      • Closely related to the aorta and its branches, named accordingly: Celiac, Superior Mesenteric, Inferior Mesenteric, Aortico-renal.
    • Terminal
      • Located close to or at the wall of effector organs.
      • Long preganglionic and short postganglionic fibers.
      • Contain all parasympathetic fibers.

    Sympathetic vs. Parasympathetic

    • Sympathetic:
      • Short preganglionic and long postganglionic fibers.
    • Parasympathetic:
      • Long preganglionic and short postganglionic fibers.

    Autonomic Nervous System (ANS)

    • The ANS regulates involuntary or visceral functions of the body.

    Divisions of the ANS

    • Sympathetic Nervous System: "Fight or flight"

      • Prepares body for activity
      • Delays onset of fatigue
      • Mass stimulation is useful
      • Increases energy expenditure
      • Catabolic to energy

    • Parasympathetic Nervous System: "Rest and digest"

      • Predominates during rest and sleep
      • Allows for repair and recovery
      • Mass stimulation can be fatal
      • Preserves energy
      • Anabolic energy

    Structure of the ANS

    • The ANS has two neurons:

      • Preganglionic neuron: Originates inside the CNS
      • Postganglionic neuron: Originates outside the CNS, in autonomic ganglia
      • End: At effector organs

    • Preganglionic neuron characteristics:

      • Thin myelinated type B
      • Few in number
      • Chemical transmitter: acetylcholine

    • Postganglionic neuron characteristics:

      • Non-myelinated type C
      • More in number
      • Chemical transmitter: acetylcholine or noradrenaline

    Autonomic Ganglia

    • Collection of cell bodies of neurons outside the CNS (peripheral nervous system)
    • Functions:
      • Relay station for autonomic preganglionic nerve fibers
      • Distributing center

    Types of Ganglia

    • Lateral (Para-Vertebral) Ganglia:

      • On both sides of the spinal cord
      • Interconnected by nerve fibers, forming the sympathetic chain
      • Short preganglionic fibers and long postganglionic fibers

    • Collateral (Pre-Vertebral) Ganglia:

      • Present mainly in the abdomen
      • Located midway between the spinal cord and viscera
      • Preganglionic fibers are about the same length as postganglionic fibers

    • Terminal Ganglia:

      • Lie close to or at the wall of effector organs
      • Long preganglionic fibers and short postganglionic fibers

    Locations of Ganglia

    • Lateral Ganglia:

      • 3 Cervical: superior, middle, inferior
      • 12 Thoracic
      • 5 Lumbar
      • 5 Sacral
      • 1 Coccygeal

    • Collateral Ganglia:

      • Celiac ganglion
      • Superior mesenteric ganglion
      • Inferior mesenteric ganglion
      • Aortico-renal ganglion

    Sympathetic vs Parasympathetic

    • Sympathetic: Short preganglionic and long postganglionic fibers
    • Parasympathetic: Long preganglionic and short postganglionic fibers
    • Adrenal Medulla: Unique effector organ in the sympathetic system directly innervated by preganglionic fibers

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