anatomy and function of the spinal cord and nerves l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Anatomy and function of the spinal cord and nerves PowerPoint Presentation
Download Presentation
Anatomy and function of the spinal cord and nerves

Loading in 2 Seconds...

play fullscreen
1 / 23

Anatomy and function of the spinal cord and nerves - PowerPoint PPT Presentation


  • 204 Views
  • Uploaded on

Anatomy and function of the spinal cord and nerves. Spinal cord Autonomic nervous system Ch. 18, 20. Spinal cord is protected by vertebrae, meninges and CSF. Canal formed by foramina of vertebrae Meninges Dura mater Arachnoid mater Pia mater CSF formed in brain

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Anatomy and function of the spinal cord and nerves' - demetria


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
anatomy and function of the spinal cord and nerves

Anatomy and function of the spinal cord and nerves

Spinal cord

Autonomic nervous system

Ch. 18, 20

spinal cord is protected by vertebrae meninges and csf
Spinal cord is protected by vertebrae, meninges and CSF
  • Canal formed by foramina of vertebrae
  • Meninges
    • Dura mater
    • Arachnoid mater
    • Pia mater
  • CSF formed in brain
    • Found in subarachnoid space
internal structure of spinal cord
Internal structure of spinal cord
  • Roots connect spinal nerves to spinal cord
  • Dorsal root- sensory neurons
    • Ganglion-cell bodies of sensory neurons
  • Ventral root- motor neurons
  • Horns- gray matter; integrates sensory and motor information
    • Anterior, posterior, lateral
  • White matter- myelinated; sensory and motor tracts
    • Columns- anterior, posterior, lateral
regions of white and gray matter
Regions of white and gray matter
  • Dorsal (posterior) horns- sensory neurons
  • Ventral (anterior) horns- motor neurons
  • Lateral horns- autonomic (motor) neurons
  • Columns- ascending (sensory) and descending (motor) tracts
sensory and motor tracts
Sensory and motor tracts
  • Named according to its position and pathway
  • Sensory impulses move up tracts and columns
  • Join the “pool” of sensory information
  • Voluntary motor output emanates form cerebral cortex (direct pathways)
  • Involuntary output originates in brain stem and hypothalamus (indirect pathways)
reflex arcs may be somatic or autonomic
Reflex arcs may be somatic or autonomic
  • Patellar reflex (knee-jerk)
    • Tap patellar ligament; quadriceps femoris contracts
  • Achilles reflex (ankle-jerk)
    • Tap calcaneal tendon; gastrocnemius and soleus muscles contract
  • Babinski sign- test for continuity of the corticospinal tract (goes from positive to negative with development)
  • Abdominal reflex
  • Can be useful for diagnosis of chronic disease or nerve damage
spinal nerves
Spinal nerves
  • Comprise the peripheral nervous system (PNS)
  • Connect the CNS to muscles, sensory receptors and glands
  • 31 pairs of spinal nerves
  • Posterior and anterior roots (mixed nerves)
distribution of spinal nerves
Distribution of spinal nerves
  • Branches (rami)
    • Posterior (muscles and surfaces; anterior
    • Meningeal branch (CNS)
    • Rami communicantes- autonomic system
  • Plexuses- network of axons
    • Cervical, brachial, lumbar, sacral
major plexuses pp 566 576 example cervical plexus
Major plexuses pp. 566-576example: cervical plexus
  • Origin (C1- C5)
  • Superficial or deep
    • Superficial- skin; mostly sensory
    • Deep-muscle; largely motor
  • Severing spine above phrenic nerve causes respiratory arrest
more plexuses
More plexuses
  • Brachial
    • Shoulders, upper limbs
    • Axial, musculocutaneous, radial, medial, ulnar
  • Lumbar
    • Anterolateral abdominal wall, genitalia, part of lower limbs
  • Sacral and coccygeal
    • Buttocks, perineum, lower limbs
  • Damage can cause loss of sensation, palsy, loss of motor control
  • Intercostal nerves directly innervate muscles (no plexuses)
dermatomes
Dermatomes
  • Sensory neurons convey information form skin to CNS
  • Dermatomes- areas of skin that provide sensory input to a particular pair of nerves
  • Some overlap
  • Can be useful for diagnosis
autonomic vs somatic nervous system
Somatic senses (pain, thermal, tactile, proprioreceptive)

Somatic motor neurons- skeletal muscle

Usually voluntary

Motor units

acetylcholine

Autonomic sensory (chemoreceptors, mechano- (stretch) receptors

Motor neurons regulate visceral activities; can function independently of ANS

Preganglionic and postganglionic neurons

Acetylcholine or norepinephrine

Autonomic vs. somatic nervous system
different types of ganglia
Different types of ganglia
  • Sympathetic
    • Sympathetic trunk
      • Innervate organs above the diaphragm
      • Superior, middle, inferior cervical ganglia
    • Prevertebral
      • Below the diaphragm
      • Celiac, superior and inferior mesenteric ganglia
  • Parasympathetic
    • Preganglionic axons are longer than in sympathetic ganglia
    • Preganglionic neurons are myelinated, postganglionic neurons are not
postganglionic neurons
Postganglionic neurons
  • Sympathetic system
    • One presynaptic neuron can diverge into many
    • Many organs can be affected at once
    • May extend to adrenal medullae
  • Parasympathetic system
    • Many presynaptic neurons can converge on a single effector
    • Effect can be localized to a single effector
action by neurotransmitters in ans
Action by neurotransmitters in ANS
  • Acetylcholine (cholinergic neurons)
    • All preganglionic
    • Sympathetic postganglionic innervation of sweat glands
    • All parasympathetic postganglionic neurons
    • Nicotinic, muscarinic receptors
  • Norepinephrine (adrenergic)
    • α and β receptors
    • Can be excitatory or inhibitory
functions of ans
Functions of ANS
  • “fight or flight” (sympathetic)
    • More widespread and longer lasting
    • Norepinephrine and epinephrine can act as hormones as well as neurotransmitters
  • “rest and digest” (parasympathetic)
    • Salivation, lacrimation, urination, digestion and defecation
    • See pp. 644-645
control of autonomic functions
Control of autonomic functions
  • Reflexes
    • Blood pressure
    • Digestion
    • Defecation and urination
  • Control within brain
    • Brain stem (cardiovascular, swallowing , digestion)
    • Spinal cord (elimination)
    • Control and integration center is hypothalamus