01_Coloring Packet Flashcards
- one axon that divides into two long processes
- usually sensory neurons
unipolar
- one axon and two or more dendrites
- most common
multipolar
- one axon and one dendrite
- rare
- round in retina and olfactory epithelium
bipolar
3 functional types of neurons
- motor
- sensory
- interneurons
Which neurons comprise more than 99% of all neurons in the body?
interneurons
What do interneurons do?
convey impulses between sensory and motor neurons
What increases the receptive area of the neurons?
dendritic spines
In the CNS, axons are myelinated by
oligodendrocytes
In the PNS, axons are myelinated by
Schwann cells
What is a dermatome?
region of skin innervated by somatic sensory nerve fibers associated with
- single spinal level
- single dorsal root
At the top of the head, the dermatome level begins at
C2
dermatome sensation
pressure
pain
How many pairs of spinal nerves does the spinal cord give rise to?
31
give rise to 2 major branches/rami
dorsal ramus
conveys motor and sensory information to and from
- skin
- intrinsic back skeletal muscles (erector spinae, transversospinales
ventral ramus
runs laterally and ventrally and innervates
- all remaining skin and skeletal muscles of the neck, limbs, trunk
somatic nervous system
sensory and motor fibers to
- skin
- skeletal muscle
- joints
autonomic nervous system
sensory and motor fibers to
- all smooth muscle
- cardiac muscle
- glands
enteric nervous system
- plexuses and ganglia of GI tract that regulate bowel secretion, absorption and motility
- linked to ANS
somatic nervous system: number of motor neurons
1
somatic nervous system: efferent
- efferent neuron in CNS
- axon projects to peripheral target
somatic nervous system: afferent
- neuron (pseudounipolar) in DRG
- conveys sensory info from skin, muscle, or joint
ANS: number of motor neurons
2
Where are the 2 neurons of the ANS?
- first neuron in CNS
- second neuron in peripheral autonomic ganglion
ANS: axon in the first neuron (in CNS)
preganglionic neuron
ANS: axin in second neuron (in peripheral autonomic ganglion)
postganglionic neuron
sensory neuron type of ANS
pseudounipolar
Where is the sensory neuron of the ANS?
DRG
What info does the sensory neuron of the ANS carry?
sensory info from the viscera to CNS
ventricle situated above the pons and rostral portion of medulla
4th ventricle
ventricle situated in midline diencephalon between thalamic nuclei
3rd ventricle
Where is CSF produced?
choroid plexus (capillary network)
- in floor of lateral ventricles
- in roof of 3rd and 4th ventricles
Direction of flow of CSF within the ventricles
- choroid plexus of lateral ventricles
- third ventricle via interventricular foramen
- fourth ventricle vis cerebral aqueduct
- spinal canal
secretion and absorption of CSF
secretion normally is matched by absorption by arachnoid granulations and small pial veins
3 types of hydrocephalus
- obstructive
- communicating
- normal pressure
obstructive hydrocephalus
congenital stenosis of either
- cerebral aqueduct
- interventricular foramina
- lateral and median apertures
may also be caused by obstructive CNS tumors that block flow
communicating hydrocephalus
- obstruction outside ventricular system
- maybe due to hemorrhage in subarachnoid space or around arachnoid granulations
normal pressure hydrocephalus
- adult syndrome
- results in progressive dementia, gait disorders, urinary incontinence
