Lecture 1: Intro & ANS Flashcards
What are the two divisions of the nervous system?
Somatic:
- Sensory to body walls, limbs, skin
- Motor to skeletal muscle
- Conscious/voluntary
Autonomic:
- Innervation of viscera, smooth muscle, blood vessels, glands
- Subconscious/involuntary
- Two neurons from spinal cord to target
What are the two divisions of somatic?
Sensory:
- Perceivable stimuli
- Touch
- Pressure
- Pain
Motor:
- Skeletal muscle
- Movement
What are the two divisions of autonomic?
Sympathetic (fight or flight) and Parasympathetic (rest and digest)
Where does sympathetic originate?
Thoraco-lumbar
Where does parasympathetic originate?
Cranio-sacral
What is the function of sympathetic?
To mobilise body energies
What is the function of parasympathetic?
To conserve body energies
What is the function of sensory fibres?
To bring information about touch, pressure and pain from the periphery to the CNS
What is the function of motor fibres?
To carry information from the CNS to skeletal muscles for movement
The cell body of motor fibres sits in the ____ while the cell body of sensory fibres sit in the ____.
The cell body of motor fibres sits in the ventral horn while the cell body of sensory fibres sit in the dorsal root ganglion
Where do sensory fibres terminate?
In the dorsal horn or continue up to the brain (CNS)
Where do motor fibres originate?
In the ventral horn
Sympathetic preganglionic fibres are ____ while parasympathetic preganglionic fibres are ____ .
Sympathetic preganglionic fibres are short while parasympathetic preganglionic fibres are long
Where do sympathetic preganglionic fibres synapse with postganglionic fibres?
In the sympathetic trunk (head and thorax)
Or
Prevertebral/visceral ganglia (abdomen)
Where do sympathetic postganglionic fibres run?
In splanchic nerves to get to abdominal and pelvic viscera
Where do parasympathetic preganglionic fibres synapse with postganglionic fibres?
Near viscera
Where do parasympathetic postganglionic fibres run?
Vagus nerve (thorax and abdomen)
Or
Pelvic splanchic nerves (pelvis)
Where are paravertebral/sympathetic ganglia found (relative to the vertebral column) ?
Ascending in a chain lateral to the vertebral column
Where are prevertebral/visceral ganglia found (relative to the vertebral column) ?
In the midline
Associated with branches of the abdominal aorta
What information do visceral afferent neurons carry?
Sensory to viscera
Distension of viscera
Visceral pain
What pathways do visceral afferent neurons follow?
Sympathetic back to CNS
Parasympathetic (vagus) back to CNS
What is referred pain?
The perception of pain in areas other than the site of stimulation
Usually due to a common spinal segmental origin of the nerves to the site of stimulation and the site to which the pain is referred
What is the probable cause of referred pain?
Due to the convergence of two inputs to the same population of neurons at a given spinal segmental level
