Peripheral%20Nervous%20System%20(PNS)%20Autonomic%20Nervous%20System%20(ANS)

1
Peripheral Nervous System (PNS) Autonomic Nervous
System (ANS)
2
Nervous System Classification-1

• Somatic Nervous System
• Motor nerves to skeletal muscle (somatic motor
  neurons)
• Upper and lower motor neurons
• Skeletal Muscle Reflexes
• Sensory, interneurons, lower motor neurons
• Visceral (organ) Reflexes
• Sensory nerves (somatosensory neurons)
• Peripheral Nervous System
• Whatever neurons are outside of CNS
• Autonomic Nervous System
• Motor nerves to smooth and cardiac muscle
  (visceral motor neurons)
• Sympathetic
• Parasympathetic

Todays lectures are the red topics
3
Nervous System Classification-2

• Efferent Nervous System
• Somatic Nervous System
• Upper and lower motor neurons to skeletal muscle
  (somatic motor neurons)
• Visceral (Autonomic) Nervous System
• Motor nerves to smooth and cardiac muscle
  (visceral motor neurons)
• Sympathetic
• Parasympathetic
• Afferent Nervous System
• Sensory nerves (somatosensory neurons)
• Reflexes

I did not organize the lectures by this method of
classification
4
VISCERAL (organ) MOTOR NERVES

• A visceral motor nerve innervates involuntary
  effectors (smooth muscles in organs or cardiac
  muscle). This is part of the ANS.
• A somatic motor nerve innervates voluntary
  effectors (skeletal muscle). It is not part of
  the ANS.
• (dont confuse this with a somatic sensory nerve
  for the sense of touch sensory nerves are not
  part of the ANS either)

5
VISCERAL (organ) SENSES

• Internal organs also have sensory nerves that
  tell you when you have eaten enough or your
  bladder is full. These are not part of the ANS
  because they are sensory.
• Not all organs have sensory nerves, for instance,
  you cant feel when you have high blood pressure.
  
• You can also have visceral reflexes, which
  trigger the parasympathetic system to contract
  the bladder when full, etc.
• Reflexes are hard to localize.

6
Nervous System Classification-1

• Somatic Nervous System
• Motor nerves to skeletal muscle (somatic motor
  neurons)
• Upper and lower motor neurons
• Skeletal Muscle Reflexes
• Sensory, interneurons, lower motor neurons
• Visceral (organ) Reflexes
• Sensory nerves (somatosensory neurons)
• Peripheral Nervous System
• Whatever neurons are outside of CNS
• Autonomic Nervous System
• Motor nerves to smooth and cardiac muscle
  (visceral motor neurons)
• Sympathetic
• Parasympathetic

Todays lectures are the red topics
7
Somatosensory Neurons

• The somatosensory system is made up of a number
  of different neurons with various receptors,
  including thermoreceptors (action potential is
  triggered by heat or cold), photoreceptors
  (triggered by light), mechanoreceptors (triggered
  by movement) and chemoreceptors (triggered by
  chemicals), proprioception (position of the
  body), and nociception (pain).
• Each somatosensory neuron specializes in
  conducting one type of sensation.
• The sensory receptors cover the skin, skeletal
  muscles, bones and joints, internal organs, and
  the cardiovascular system.

8
Somatic Senses

• Pain
• Haptic perception
• Deep Pressure
• Light Touch
• Vibration
• Thermoception (Hot/Cold)
• Two-point discrimination
• Proprioception
• Special senses

These are routinely tested by doctors in a
physical exam, especially for people with
diabetes and lupus.
9
Sense of Touch

• Touch is a laymans term. It is not specific in
  what it describes.
• Touch includes mechanoreception (deep pressure,
  light touch, vibration and proprioception), pain
  (nociception) and heat (thermoception). Since
  each of these are different neurons, each of
  these has to be tested separately.

10
Sense of Pain

• A nociceptor is a receptor of a sensory neuron
  (nerve cell) that responds to potentially
  damaging stimuli by sending signals to the spinal
  cord and brain.
• This process, called nociception, usually causes
  the perception of pain.
• They travel in the dorsal column pathway in the
  spinal cord, ascend to the thalamus in the brain,
  and go to the cerebral cortex.

11
Referred Pain

• Pain in an organ may not be where the organ is.
• Heart pain usually manifests in the left side of
  chest, the left shoulder, arm, but not the heart.
  
• This is REFERRED PAIN.
• Pain in the lungs usually shows up as neck pain.
• Hip pain often presents as the appearance of a
  groin injury.
• These areas of referred pain are important to
  know, but not for this class.

12
A Map of Referred Pain
13
Complex regional pain syndrome (CRPS)

• Formerly called Reflex Sympathetic Dystrophy
  (RSD)
• Chronic progressive disease characterized by
  severe pain, swelling, and changes in the skin.
• It often affects an arm or a leg and may spread
  to another part of the body and is associated
  with dysregulation of the autonomic nervous
  system resulting in multiple functional loss,
  impairment, and disability.
• Symptoms include burning and shooting pains and
  edema that occur more often during times of
  stress.
• Treatment is often unsatisfactory. Early
  multimodal therapy can cause dramatic improvement
  or remission of the syndrome in some patients.
• http//losangeles.cbslocal.com/video/9805202-there
  s-no-cure-for-complex-regional-pain-syndrome-but-d
  octors-say-treatment-offers-hope/

14
Treatment for Pain

• Somatosensory Rehabilitation of Pain is a method
  whose aim is to treat conditions of a reduced
  sense of touch or sensation (hypoesthesia) in
  order to decrease neuropathic pain.
• Neuropathic pain, with a prevalence of 7 of the
  general population, represents an important
  public health problem.

15
Treatment for Pain

• Examples of pain syndromes include
• Carpal Tunnel Syndrome (CTS) concerns 3 of the
  general population.
• Complex Regional Pain Syndrome (CRPS) concerns
  26/100,000.
• Patients with chronic pain might use
  transcutaneous electrical nerve stimulation (TENS
  unit) and other physical therapy modalities,
  which bring substantial pain relief to large
  numbers of people.

16
Haptic perception(Sense of Touch)

• Deep Pressure
• Light Touch

17

• While touch (also called tactile perception) is
  considered one of the five traditional senses,
  the impression of touch is formed from several
  modalities including pressure, skin stretch,
  vibration and temperature.
• There are separate neurons for each of those
  sensations, and each group of neurons must be
  evaluated during a physical exam.
• In medicine, the colloquial term "touch" is
  usually replaced with "somatic senses" to better
  reflect the variety of mechanisms involved.

18
Haptic perception

• Haptic perception is the process of recognizing
  objects through touch. It involves a combination
  of somatosensory perception of patterns (e.g.,
  edges, curvature, and texture) on the skin
  surface and proprioception of hand position and
  conformation (what position do my finger go into
  while tracing the surface of the object?).

19
Haptic perception

• People can rapidly and accurately identify
  three-dimensional objects by touch.They do so
  through the use of exploratory procedures, such
  as moving the fingers over the outer surface of
  the object or holding the entire object in the
  hand.

20

• Haptic perception is active exploration, whether
  with a body part or a tool, such as feeling the
  contours of something by using a stick to touch
  it.
• Haptic perception allows the creation of
  "virtual", illusory haptic shapes with different
  perceived qualities.
• Loss of the sense of touch is a catastrophic
  deficit that can impair walking and other skilled
  actions such as holding objects or using tools.

21
Disorder of Sense of Touch

• One disorder of the sense of touch
• Allochiria

22
Allochiria

• Allochiria (from the Greek meaning "other hand")
  is a neurological disorder in which the patient
  responds to stimuli presented to one side of
  their body as if the stimuli had been presented
  at the opposite side.
• It is associated with spatial transpositions,
  usually symmetrical, of stimuli from one side of
  the body (or of the space) to the opposite one.
  Thus a touch to the left arm will be reported as
  a touch to the right arm
• If the auditory or visual senses are affected,
  sounds (a person's voice for instance) will be
  reported as being heard on the opposite side to
  that on which they occur and objects presented
  visually will be reported as having been
  presented on the opposite side.
• Commonly from damage to the right parietal lobe.

23
Allochiria

• Allochiria can also occur to other senses.
• Motor Allochiria
• Reflex Allochiria
• Audio Allochiria
• Visual Allochiria
• Gustatory Allochiria

24
Sense of Vibration

• Pallesthesia refers to the sensation of
  mechanical vibration on or near the body.
• Vibration sense may be lost as a result of a
  number of lesions to the nervous system, often in
  conjunction with other deficits.
• The word "pallesthesia" is derived from the Greek
  pallein, meaning "to shake."
• Pallesthesia may be tested for using a vibrating
  mechanical tuning fork, placed on a bony
  prominence.

25
Thermoception(Sense of Hot/Cold)

• Thermoception is the sense of heat and the
  absence of heat (cold) by the skin.
• There are specialized receptors for cold
  (declining temperature) and for heat.
• Cold receptors help an animals sense of smell,
  telling wind direction. Heat receptors help
  animals that can use radiation to detect prey,
  such as snakes.
• The information travels up the spinothalamic
  tract in the spinal cord and ascends to the
  thalamus.
• The thermoceptors in the skin are quite different
  from the homeostatic thermoceptors in the brain
  (hypothalamus), which provide feedback on
  internal body temperature.

26
Two-point discrimination

• Two-point discrimination is the ability to
  discern that two nearby objects touching the skin
  are truly two distinct points, not one.
• It is often tested with two sharp points during a
  neurological examination and is assumed to
  reflect how finely innervated an area of skin is
  and diagnosing tactile agnosia (dont know what
  is touching me).

27
Two-point discrimination

• The therapist randomly alternates between
  touching the patient with one point or with two
  points on the area being tested (e.g. finger,
  arm, leg, toe).
• The patient is asked to report whether one or two
  points was felt. The smallest distance between
  two points that still results in the perception
  of two distinct stimuli is recorded as the
  patient's two-point threshold.

28
Two-point discrimination

• Performance on the two extremities can be
  compared for discrepancies.

29
PROPRIOCEPTION

• There are sensors within the muscles and joints
  that measure the amount of force, movement, and
  position.
• Proprioception neurons travel up the
  spinocerebellar tract. The brain can then
  interpret whether you are off balance, then send
  a command to the muscles to contract and
  straighten yourself up so you dont fall.
• Note that this sense of balance is NOT the same
  as the sense of balance from equilibrium in the
  ears. Proprioception neurons are located within
  the muscles and joints.
• During a physical exam, a doctor will test the
  patients proprioception ability by telling them
  to close their eyes and place their finger on
  their nose. This may indicate a lesion in the
  cerebellum. Who else may ask you to do this test?
  Alcohol disrupts the cerebellum.

30
Muscle spindles

• Muscle spindles are sensory receptors within the
  belly of a muscle that primarily detect changes
  in the length of this muscle. The brain can then
  determine the position of body parts.
• Muscle spindle responses also play an important
  role in regulating the contraction of muscles, by
  activating motor neurons via the stretch reflex
  to resist muscle stretch.

31
Proprioceptors

• Sensory receptors that report on internal events
  in your muscles and joints.
• They report on muscle stretch and joint position.
  
• They generate electrical impulses that will
  travel up neurons to the CNS.
• A muscle spindle is one type of proprioceptor.

32
Proprioception Disorders

• Not enough vitamin B1 (memory problems)
• Too much vitamin B6 (balance problems)
• Damage to proprioceptors can occur from consuming
  excess vitamin B6 (pyridoxine).
• Patients cannot tell where their body parts are
  unless they look at them.
• They have difficulty with all motor tasks
  including walking, eating, dressing, etc.
• They must use their vision to watch each body
  part to make it move in the right direction.

33
PROPRIOCEPTORS

• Proprioception is often tested by having the
  patient close their eyes and saying if their
  thumb is up or down.
• Proprioceptors send information to the
  cerebellum. Thats how you know your legs are
  crossed before you stand up.
• Somatic senses and proprioception are NOT
  considered special senses.

34
Somatic Senses

• Pain
• Haptic perception
• Deep Pressure
• Light Touch
• Vibration
• Thermoception (Hot/Cold)
• Two-point discrimination
• Proprioception
• Special senses (these are not somatic)

35
Special senses

• The special senses are those that have
  specialized organs devoted to them
• vision (the eye)
• hearing and balance (the ear)
• smell (the nose)
• taste (the tongue)

These will be discussed in a separate lecture.
36

• Somatic sense information goes into the spinal
  cord, travels up a tract and into the primary
  somatosensory area in the parietal lobe of the
  cerebral cortex.
• The mapping of the body surfaces in the brain is
  called a homunculus and plays a fundamental role
  in the creation of body image. Loss of an arm may
  cause phantom limb syndrome.

This brain-surface ("cortical") map is not
immutable, however. Dramatic shifts can occur in
response to stroke or injury.
37
SENSORY CUTANEOUS NERVES

• These come out of the spinal cord and go to
  specific regions of skin on the body.
• For example, nerve C4 innervates the skin region
  C4 of the DERMATOME MAP.
• Its important to know these dermatome map
  regions (not for this class), especially physical
  therapists and nurses.

38
Dermatome Map

• If a patient has a shooting pain down the
  anterior shin, what nerve is pinched? L5.
• Numbness in pinky and ring finger is what nerve?
  C8.
• If a workmans comp patient comes in saying his
  whole hand is numb, no other symptoms, you know
  hes lying because the nerves dont run that way.
  

39
DAMAGE TO THE NERVOUS SYSTEM

• If a person has a spinal cord injury in their
  cervical region, they could have
  quadriplegia/tetraplegia (arms and legs
  paralyzed).
• If a person has a spinal cord injury in their
  thoracic region, they could have paraplegia (just
  legs are paralyzed).

40
Disruption of Blood Supply

• When a body part falls asleep, the region has
  become ischemic (lack of blood flow), impairing
  the action potential of the nerves.
• Unlike the CNS, when blood is restored to the
  PNS, the nerves recover.
• Damage to the CNS tends to be permanent, but
  damage to the PNS tends to heal.

41
Cut nerves

• If a small nerve is cut, it will regenerate
  because where are the cell bodies? In the
  posterior root ganglion (sensory) or anterior
  horn (motor).
• Since the cell body is about a meter away, axons
  can regrow.
• Large nerves are harder to regrow, but you can
  still stitch the ends together at the epineurium
  and perineurium, and you may get healing.

42
Doctors trying to fix damaged nerves

• http//www.foxnews.com/health/2012/11/13/doctors-t
  rying-to-fix-damaged-nerves/ 
• Nerve disease and injuries are tough to treat,
  largely because there's no way to regenerate many
  damaged nerve cells. Neurologist Joseph Corey is
  trying to change that.
• Corey and a team of scientists used tiny polymer
  fibers as a scaffold. They coaxed an
  oligodendrocyte to form a myelin sheath around
  the fiber. The artificial fiber mimicked an axon.
• Myelin provides the pathways along which some
  nerve cells regenerate after an injury. When a
  person has MS or cerebral palsy, the
  oligodendrocytes are damaged and don't function
  properly and the myelin sheaths start to break
  down.

43
Rat Brain in a Dish Flies Plane

• An electrode grid was placed at the bottom of a
  glass dish and then covered with rat neurons that
  gradually formed a neural network -- a brain.
• They then used the brain to control an F-22
  fighter jet flight simulator.
• The research could lead to tiny, brain-controlled
  prosthetic devices and unmanned airplanes flown
  by living computers.

44
Exoskeleton Helps Paralyzed Patients Walk

• Exoskeletons have been designed for military use
  and boosting strength. But the same technology
  that makes people able to lift heavier loads
  might also one day allow those with spinal
  injuries to walk.
• Ekso Bionics, a California company, developed the
  Human Universal Load Carrier, or HULC for the
  military, and another one called the Ekso, for
  people who need either physical therapy or
  rehabilitation.

45
Tens unit

• Transcutaneous electrical nerve stimulation

TENS is usually applied at high frequency with an
intensity below motor contraction. It just blocks
pain impulses. This is a different machine than
a muscle stimulator, but they look the
same. TENS is available without a Rx.
46
Corydalis powder for pain

• http//www.prevention.com/health/health-concerns/c
  hinese-remedy-corydalis-pain

Put ½ teaspoon into one cup of hot fluid (tea,
etc) and drink it. Alleviates chronic pain in
about 20 minutes!
47
Pinched nerves

• When a nerve gets pinched (e.g. herniated disc),
  it damages the nerve by interfering with its
  action potential, causing weakness, pain, or
  paralysis.

48
Nervous System Classification-1

• Somatic Nervous System
• Motor nerves to skeletal muscle (somatic motor
  neurons)
• Upper and lower motor neurons
• Skeletal Muscle Reflexes
• Sensory, interneurons, lower motor neurons
• Visceral (organ) Reflexes
• Sensory nerves (somatosensory neurons)
• Peripheral Nervous System
• Whatever neurons are outside of CNS
• Autonomic Nervous System
• Motor nerves to smooth and cardiac muscle
  (visceral motor neurons)
• Sympathetic
• Parasympathetic

Todays lectures are the red topics
49
Spinal Nerves Posterior View
Peripheral Nerves are motor nerves that have left
the spinal cord or sensory nerves that have not
yet entered the spinal cord.
50
SOME CLINICALLY IMPORTANT PERIPHERAL NERVES

• Note an epidural nerve block during child birth
  will numb the mother from her navel to her knees.
• PUDENDAL NERVE this is the nerve that can be
  anesthetized during childbirth as an alternative
  to an epidural (a pudendal nerve block is also
  called a saddle block because the numb areas are
  where you would be touching a saddle).
• PHRENIC NERVE allows the diaphragm to contract.
  If it gets severed, the person can no longer
  breathe without assistance.

51
Nerve Plexus

• A PLEXUS is a network of nerves that primarily
  serves the limbs. There are four major plexi
  cervical, brachial, lumbar, and sacral.
• 1. CERVICAL PLEXUS comes out of the neck and are
  cutaneous nerves (sensory input of the skin) of
  the neck and back of the head. The phrenic nerve
  (supplies the diaphragm) is also in this plexus.

52
Cervical Plexus
53
BRACHIAL PLEXUS

• 2. BRACHIAL PLEXUS
• This is the major group of nerves that supply the
  upper limbs. It runs through the axilla.
• If a person leans their armpits on their
  crutches, they can damage this plexus and lose
  the use of their arms (crutch paralysis).
• The nerves in the brachial plexus change names as
  they go to different regions in the arm.

54
The Brachial Plexus
55
Major Nerves of the Upper Extremity
Axillary
Musculocutaneus
56
Axillary Nerve

• Deltoid

57
Musculocutaneus Nerve

• Supplies anterior muscles of the arm

58
Instead of radial and ulnar nerve, we have median
and ulnar nerve.Median Nerve

• Supplies no muscles of the arm
• Supplies anterior forearm (except flexor carpi
  ulnaris)
• Damage can cause
• Hand of benediction
• Ape Hand
• Carpal Tunnel Syndrome

Patient trying to make a fist
59
MEDIAN NERVE Ape Hand

• This is the nerve that gets cut when people try
  to slit their wrists.
• The arteries are so small in the wrist people
  rarely die from this type of suicide attempt.
• However, they live with a lot of tissue damage.
• They are not able to move the thumb towards the
  little finger, so it is hard to pick up small
  objects.
• This is called ape hand.

60
(No Transcript)
61
Carpel Tunnel Syndrome
62
Median NerveCarpel Tunnel Syndrome

• The median nerve travels under the transverse
  carpal ligament.
• The nerve is pinched in carpal tunnel syndrome.

63
Carpel Tunnel Syndrome
64
Patient Case

• George has been a computer programmer for 20
  years. He has numbness in his right hand on the
  thumb, index finger, and middle finger.
• Tapping on the carpal tunnel causes parathesias
  (tingling) in the median nerve distribution
  (positive Tinels sign).
• Placing his wrist in sustain flexion for one
  minute also causes the parathesias (positive
  Phalens test).

65
Patient Case

• Diagnosis is carpal tunnel syndrome. Treatment
  began with splinting the wrist in neutral
  position and patient education for proper
  ergonomics (how to use your body at work without
  injury). George was told to use a wrist pad while
  typing).

66
Ulnar Nerve

• Supplies flexor carpi ulnaris
• Funny Bone
• Damage can cause claw hand cannot adduct or
  abduct fingers

67
Radial Nerve

• Supplies muscles on the posterior arm and forearm
• Triceps brachii
• Extensor carpi radialis
• Extensor digitorum
• Damage can cause wrist drop
• Also called waiters hand

68
Carpel Tunnel Syndrome
Ape Hand
69
Axillary, Musculocutaneus, Ulnar, Median, Radial,
Nerves
Figure 14.4
70
Brachial Plexus

• Damage to Brachial Plexus
• Congenital (brachial plexus damaged during birth
  the baby comes out arm first and someone pulls
  it)
• Klumpkes paralysis
• Acquired Brachial Plexus injuries
• Crutch paralysis (total upper extremity
  paralysis)
• Claw Hand
• Carpal Tunnel Syndrome, Ape hand, Hand of
  benediction
• Wrist Drop (Waiters Hand)

71
LUMBAR PLEXUS

• 3. LUMBAR PLEXUS
• FEMORAL NERVE is the main nerve to the anterior
  thigh.

72
Lumbo-Sacral Plexus

• Lumbar
• Femoral nerve
• Sacral
• Sciatic nerve

73
The Lumbar Plexus
Figure 14.15
74
Sacral Plexus

• 4. SACRAL PLEXUS are spinal nerves from L4-S5
• Some of the fibers from the lumbar plexus mix
  with the sacral plexus, so these are often
  referred to together as the lumbosacral plexus.
• SCIATIC NERVE is the largest branch of the sacral
  plexus and the largest nerve in the body it is
  about the size of your pinky finger. It leaves
  the pelvis through the greater sciatic notch.
• A short, thick muscle (Piriformis muscle) covers
  the greater sciatic notch, and when it contracts,
  it can pinch the sciatic nerve, causing a type of
  sciatica (sciatic nerve irritation) known as
  piriformis syndrome.
• This can be alleviated by stretching exercises
  (lay on back and move knee to opposite shoulder).
  However, sciatica can also be caused if there is
  a herniated lumbar disc, in which case stretching
  exercises make it worse.

75
The Sacral Plexus
Figure 14.16a, c
76
(No Transcript)
77

• Sciatica tremors video

78
Spinal steroid shots may have little effect on
sciatica

•  http//www.foxnews.com/health/2012/11/13/spinal-s
  teroid-shots-may-have-little-effect-on-sciatica/
• For the back pain component of sciatica, the
  researchers found that the injections didn't seem
  to make a difference over short or long periods
  of time.
• When it came to leg pain, there was no difference
  a year or so after the injection, but there was a
  statistically significant drop in pain scores
  over the short term - about 2 weeks to 3 months.

79
(No Transcript)
80
Nerves of the Lower Extremity
Obturator
Femoral
The sciatic nerve supplies the back of the thigh,
then branches out into the TIBIAL and FIBULAR
(peroneal) nerves, which supply the leg and
foot. The fibular nerve branches into superficial
and deep.
81
Lower Extremity Nerves

• Obturator Nerve
• Supplies adductor muscles
• Femoral Nerve
• Supplies anterior Thigh
• Sciatic Nerve
• Supplies posterior thigh
• Tibial Nerve
• Supplies posterior leg and foot
• Common Fibular Nerve
• Superficial branch
• Supplies lateral side of leg
• Deep branch
• Supplies anterior leg
• Injury causes Foot Drop

82
Tibial Nerve

• Sometimes a small branch of the tibial nerve in
  the foot gets pinched between the metatarsal
  heads, and the irritation causes nerve swelling
  and pain.
• It is called a neuroma (nerve tumor) and
  manifests as pain in the ball of the foot, made
  worse with high heels.

83
(No Transcript)
84
Nervous System Classification-1

• Somatic Nervous System
• Motor nerves to skeletal muscle (somatic motor
  neurons)
• Upper and lower motor neurons
• Skeletal Muscle Reflexes
• Sensory, interneurons, lower motor neurons
• Visceral (organ) Reflexes
• Sensory nerves (somatosensory neurons)
• Peripheral Nervous System
• Whatever neurons are outside of CNS
• Autonomic Nervous System
• Motor nerves to smooth and cardiac muscle
  (visceral motor neurons)
• Sympathetic
• Parasympathetic

85
Efferent Nervous System
Somatic Division
Visceral (Autonomic) Division
Parasympathetic
Sympathetic
Smooth muscle, cardiac muscle, and glands
Blood vessel
86
AUTONOMIC NERVOUS SYSTEM

• We dont have voluntary control over these
  nerves.
• They are involved digestion, blood flow,
  urination, defecation, glandular secretion.
• Therefore, the ANS supplies the glands, smooth
  muscle, and cardiac muscle, but NOT the skeletal
  muscle.
• For this reason, the ANS is also called the
  general visceral motor system.

87
Sympathetic Division of the ANS
88
ANS

• All of the neurons of the ANS are motor neurons
  (there are no sensory neurons in the ANS).
• The ANS motor neurons differ from the somatic
  motor neurons (for skeletal muscle) because the
  ANS has two lower motor neurons in the periphery
  (the cell body of one is in the spinal cord and
  the cell body of the other is in the periphery),
  whereas the somatic motor neurons have one lower
  motor neuron, and its cell body is within the
  spinal cord, not in the periphery.

89
ANS has TWO lower motor neurons
Post-ganglionic neuron
Preganglionic neuron
Ganglion (where the cell bodies of the
post-ganglionic neurons are)
Somatic system has just one lower motor neuron
90
ANS

• The ANS lower motor neuron comes from the spinal
  cord and synapses on the cell body of another
  neuron, which then synapses on the target (gland,
  blood vessel or organ).

91
Ganglia

• The area where the two neurons come together is
  the AUTONOMIC GANGLIA.
• The first neuron is the PRE-GANGLIONIC NEURON.
• The second neuron is the POST-GANGLIONIC NEURON.

92
ANS

• The ANS motor unit is characterized by having
  more than one lower motor neuron, the axons are
  usually unmyelinated (since they are only going
  to organs), conduction is slow, and the axons are
  thin (which also slows conduction like a freeway
  with only one lane).
• The ANS has two divisions sympathetic and
  parasympathetic.

93
SYMPATHETIC DIVISION(has nothing to do with
sympathy!)

• ?heart rate and blood pressure,
• ?metabolic activity (increased blood glucose),
• decreased peristalsis (decreased food digestion)
• dilation of bronchioles
• constricts blood flow to the skin
• sweating

94
Sympathetic Division

• E.g. when running, ?heart rate sympathetic.
• When hot ? sweat sympathetic.
• The term Fight or Flight is inaccurate it
  refers to the ? heart rate, etc, but the
  sympathetic division is also active when relaxing
  on a nice beach with a cool drink on a hot day,
  because whenever youre sweating, thats the
  sympathetic division.
• Sympathetic NS and sympathy are opposites. They
  should call it the ANTI-sympathetic system.

95
(No Transcript)
96
ANATOMY OF THE SYMPATHETIC DIVISION

• The sympathetic neurons exit the spinal cord at
  the thorax and lumbar regions.
• The axons of most pre-ganglionic neurons in the
  sympathetic division are fairly short, and they
  synapse quickly on a ganglia.
• All these ganglia are lined up along the
  vertebral column and are called the SYMPATHETIC
  TRUNK (CHAIN) GANGLIA.
• Therefore, the postganglionic cell bodies of the
  sympathetic nervous system are in the chain
  ganglia.
• There are also nerves that connect the ganglia to
  each other.

97
Sympathetic Trunk Ganglia
98
Sympathetic Division
In Sympathetic division, preganglionic axons are
SHORT because they terminate in ganglia that are
close to the spinal cord
That means the post-ganglionic axons are LONG,
because they have to reach all the way to the
target muscle.
99
Sympathetic Division

• The axons of POST-GANGLIONIC NERVES are very
  long, and go to the target organs.
• Some pre-ganglionic neurons go into to the
  abdomen.
• They create a group of ganglia in the abdomen
  called the SOLAR PLEXUS (sun).
• When you get punched in the abdomen, you are
  punched in the solar plexus, and get the wind
  knocked out of you. It causes the diaphragm to go
  into spasm.

100
PARASYMPATHETIC DIVISION

• Unlike the sympathetic division, the axons of the
  preganglionic neurons of the parasympathetic
  division are long, and the axons of the
  postganglionic neurons are short.
• The nerve cell bodies (peripheral ganglia) of the
  parasympathetic division are closer to the organs
  being innervated than in the sympathetic
  division.
• In fact, the cell bodies are either next to or
  inside of the target organs. Therefore, they have
  short post-ganglionic fibers.

101
Parasympathetic Division
In the Parasympathetic division, preganglionic
axons are LONG because they terminate in ganglia
that are close to the target organ
That means the post-ganglionic axons are SHORT
102
PARASYMPATHETIC DIVISION

• Rest and Digest
• Involved in vegetative activities, such as
  digestion, voluntary urination and defecation
• Has postganglionic cell bodies in terminal
  ganglia, located either near or within target
  organs
• Has both preganglionic and postganglionic neurons
  that secrete acetylcholine
• Has preganglionic cell bodies located in the
  cervical (Vagus nerve) and sacral areas.

103
Parasympathetic Division

• The function of this division is often
  antagonistic (opposite) of the sympathetic, but
  actually, they work together.
• The parasympathetic division inhibits cardiac
  contraction, so there is ?heart rate, constricts
  bronchioles, activates digestive system, and
  causes salivation, urination, and defecation.
• When you are lounging on the beach, the heart
  rate decreases (parasympathetic), but the sweat
  increases (sympathetic).

104
Vagus Nerve

• The parasympathetic neurons come out of either
  the brain or the sacral region of the spinal
  cord.
• The majority of the parasympathetic outflow from
  the head is by the vagus nerve.
• One thing the Vagus nerve does is cause
  vasodilation of blood vessels to lower the blood
  pressure when baroreceptors tell the brain that
  blood pressure is too high.

105
Vasovagal Syncope (Fainting)

• The most common type of fainting.
• After a stressful trigger where your blood
  pressure goes up, the brain senses this and tells
  the Vagus nerve to get to work. The Vagus nerve
  tells all the blood vessels in the body to open
  up to lower the blood pressure.
• The heart rate speeds up at first.
• Then Vagus nerve kicks in and the blood pressure
  drops too much.
• Unconsciousness results.
• Treatment elevate the legs above the heart for a
  few minutes, and make sure the airway remains
  open.
• A cold, wet cloth on the forehead and back of the
  neck may make the person feel better as they
  recover.

106
Path of the Vagus Nerve
107
Reynaud's Phenomenon

• Autonomic nervous system (sympathetic division)
  is hyperactive in the ANS neurons that innervate
  the walls of blood vessels.
• It causes spasms of peripheral blood vessels,
  cuts off some blood supply, and causes the
  fingers and toes to be white or blue.
• Emotional stress and being cold tend to trigger
  the discoloration.

108
Other things that can cause vasoconstriction
Caffeine

• With frequent use, tolerance to many of the
  effects of caffeine will develop. Caffeine causes
  vasoconstriction. In doses of 600 milligrams
  (about six cups of coffee) or more daily,
  caffeine can cause nervousness, sweating,
  tenseness, upset stomach, anxiety, and insomnia.
  It can also prevent clear thinking and increase
  the side effects of certain medications. This
  level of caffeine intake represents a significant
  health risk.

109
Caffeine

• Caffeine can be mildly addictive. Even when
  moderate amounts of caffeine are withdrawn for 18
  to 24 hours, one may feel symptoms such as
  headache, fatigue, irritability, depression, and
  poor concentration. The symptoms peak within 24
  to 48 hours and progressively decrease over the
  course of a week. To minimize withdrawal
  symptoms, experts recommend reducing caffeine
  intake gradually.

110
Caffeine

• At levels over 200 milligrams per day, caffeine
  may delay conception and doubles the risk of
  miscarriages and low birth weight babies.
• Black tea and green tea are also dangerous,
  despite what you see on the market today. Herbal
  tea is ok. Caffeine and tannin in tea decreases
  iron and protein absorption, and is especially
  dangerous during pregnancy. Black tea during
  pregnancy causes birth defects.
• Caffeine taken during pregnancy is thought to
  increase the probability of a child contracting
  diabetes.
• Because children have developing nervous systems,
  it is important to moderate their caffeine
  consumption.

111
Caffeine, per cup

• Ammo 1140 mg
• Redline Power Rush 946 mg
• Expresso 500 mg
• Jolt Energy 300 mg
• Rockstar Energy 160 mg
• Coffee 100 mg
• Red Bull 80 mg
• Mountain Dew 60 mg
• Green tea 50 mg
• Tea 50 mg
• Coke 37 mg
• Dark Chocolate (1.5 oz) 20 mg
• Milk Chocolate (1.5 oz) 9 mg
• Hot Chocolate 5 mg
• Root Beer, Ginger ale, Lemon-Lime 0 mg

The Ammo and Redline manufacturers recommend
users dilute the concentrated energy drink prior
to consumption. They also claim that drinkers
should not just drink the shot straight out of
the bottle due to the extreme potency!
112
Symptoms of Excess Caffeine

• nervousness                  headache   
            increased heart rate
•  anxiety                           upset
  stomach      irregular heartbeat
•  irritability                       GI
  irritation           elevated BP
•  agitation                        
  heartburn              increased cholesterol
•  tremors                         
  diarrhea                nutritional deficiencies
•  insomnia                       
  fatigue                  poor concentration
• depression                     
  dizziness              bed wetting

113
Caffeine Withdrawal Symptoms

• headache                       constipation       
     runny nose
• craving                           
  anxiety                 nausea
• irritability                        
  nervousness         vomiting
• insomnia                        
  shakiness              cramps
• fatigue                            
  dizziness              ears ringing
• depression                     
  drowsiness           hot and cold
•  apathy                            inability to
  concentrate