anatomy and histology of the nervous system (1) Flashcards
what is the structural unit of the nervous system?
neuron
what is neuron made up of?
cell body, dendrite, axon
What supplies the energy in the both the presynaptic and postsynaptic regions?
mitochondria
types of neurons
unipolar, bipolar, multipolar, special (purkinje, stellate, pyrimidal)
what kind of neurons in retina?
bipolar
multipolar neurons
have multiple axons
golgi preparation
isolates individual neurons for viewing
nissl preparation
good for demonstrating cell bodies of neurons
myelin preparations
stain myelinated fibers and not the cell bodies or dendrites
H&E preparation (Haematoxylin and Eosin)
usually used for normal nerve tissue staining
Central Nervous system
brain and spinal cord
Peripheral Nervous system
nerves and ganglia outside the brain and spinal cord. contains 12 cranial nerves (except CN III)
collections of axons that carry action potentials from one place to another are called
nerves in the PNS
tracts in the CNS
clusters of neuron cell bodies are called
ganglia in the PNS
Nucleu in the CNS
glial cells
non-neural cells that provide a variety of support functions for the neurons that relate to nutrition, regulation of the extracellular environment including the blood brain barrier, immune system, myelin insulation for many axons, and a host of other support functions. 10x more glial cells than neurons
Astrocyte
CNS. end-feet form contacts with capillaries that help produce the blood brian barrier and from contacts on newurons that play a role in supplying nutrients to these cells. Regulate the ionic composition and pHo of the extracellular environment and secrete various neuroactive substances. glia limiatan (inner surface of pia)
microglia
clean up cellular debri via phagocytosis
satellite
form the blood brain barrier within the CNS, function similarly to astrocytes
Ependymal
form epithelial lining of the CNS and produce CSF
Oligodendrocytes
myelinated axons of the neurons in the CNS
Schwann cells
myelinated axons of the neurons in the PNS
Dura Matter
tough outermost lining covering the brain and spinal cord
arachnoid mater
delicate fibrous membrane forming the middle of the three coverings of the CNS.
Pia mater
delicate innermost layer of the meninges, the membrane surrounding the brain and spinal cord.
forebrain
anterior part of the brain, including the cerebral hemispheres, the thalamus, and the hypothalamus. also called proencehalon
Hindbrain
the lower part of the brainstem, comprising the cerebellum, pons, and medulla oblongata. also called the rhombencephalon
brain and spinal cord divisions from superior to inferior
telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon, spinal cord
telencephalon
consists chiefly of the cerebral hemispheres
diencephalon
contains the epithalamus, thalamus, hypothalamus, and ventral thalamus, and the third ventricle
Mesencephalon
commprises the tectum, tegmentum, the cerebral aqueduct, and the cerebral peduncles, as well as several nuclei and fasciculi
metencephalon
pons and cerebellum
myelencephalon
medulla oblongata
spinal cord
extends from medulla to a space called the 1st and 2nd lumbar vertabrae. Does NOT extend the entire length of the vertebral column
Grey matter
cell bodies, dendrites, and axon terminals. all synapses are here. do not have extended axons. 40% of brain. no myelin
White matter
made of axons connecting different parts of grey matter to each other. 60% of brain, myelin is responsible for white color
schwann cell
produces myelin in the PNS. wrapping from outside to inside
oligodendrocytes
produces myelin in the CNS.
Node of Ranvier
gaps on the axon between the myelination. Allows for electrical “jumping” of signal
Spinal cord organization
medulla to L1 and L2. Grey “H”, area around the “H” is white matter.
conus medullaris
end of the spinal cord where it then transistions to filum terminale
filum terminal
prolongation of pia mater coming off of the conus medullaris. decends to the back of the coccyx.
posterior root gangion
give rise to peripheral and central nerve fibers. 31 pairs of spinal nerves
intervertebral foramen
roots escape from spinal cord here
fasicle
bundle of neurons surrounded by connective tissue
Nerve
a bundle of fasicles surrounded by CT
epineurium
dense, irregular CT that surround all peripheral nerves
perineurium
layer of CT containing many flattened fibroblasts that surround each fasicle. blood nerve barrier
endoneurium
loose CT within the fasicle that surrounds each axon
posterior root
contains only sensory neurons
anterior root
contains axons of motor neurons and fibers from the autonomic nervous system
PNS contains what
the nerve fibers carry motor, sensory, and autonomic nerve fibers
spinal nerve
mixed nerve which carries motor, sensory, and autonomic singnals between the spinal cord and the body. 31 pairs of spinal nerves with one on each side of the vertebral column
How many pairs of cervical nerves are there?
8
How many pairs of thoracic nerves are there?
12
How many pairs of lumbar nerves are there?
5
How many pairs of sacral nerves are there?
5
How many pairs of Coccygeal nerves are there?
1
PNS contents
31 sets of spinal nerves, 12 sets of cranial nerves
Which cranial nerve is part of the CNS instead of the PNS?
Optic Nerve (CNII). The myelin on the optic nerve is produced by oligodendrocytes rather than schwann cells and it is encased in the meningeal layers instead of the standard endoneurium, perineurium, and epineuriem of the PNS
Cranial nerves in order
I Olfactory II Optic III Oculomotor IV Trochlear V Trigeminal VI abducent VII Facial VIII Vestibulocochlear IX glossopharyngeal X vagus XI spinal accessory XII hypoglossal
Dermatome
area of skin that is supplied nerves from a single spinal root
Autonomic Nervous System
sympathetic, parasympathetic, enteric
Where does the sympathetic nervous system originate?
T1-L2 only
Where are the cell bodies of the sympathetic nervous system located?
lateral grey horn of the thoracic and upper lumbar spinal cord
What are the four different things the preganglionic fibers of the sympathetic system can do?facial
- some fibers synapse in the nearest ganglion. Post ganglionic fibers enter T1-L2
- preganglionic fibers shoot up the sympathetic chain to a different ganglion
- Preganglionic fibers shoot down the sympathetic chain to a different ganglion
- Preganglionic fibers won’t connect in the chain, move through smypathetic chain, connect to splanchnik chain near organ
What is the location of the parasympathetic
cranial-saccral
what cranial nerve is responsible for the parasympathetic system?
vagus
what does the oculomotor nerve innervate, what ganglion?
ciliary gangliom. sphincter of the pupil and the ciliary muscle
what does the facial nerve innervate, what ganglion?
pterygopalatine ganglion, lacrimal and nasal gland
submandibular gland, submandibular and sublingual glands
what does theglossopharyngeal nerve innervate, what ganglion?
otic ganglion, parotid gland
what does the vagus nerve innervate, what ganglion?
mural or intramural ganglia of heart, lungs, lower esophagus, stomach, pancreas, gall bladder, small intestine, ascending and transverse parts of the colon
dorsal root
sensory
anterior root
motor
what neurotransmitter does the parasympathetic system use?
acetylcholine
what neurotransmitter does the sympathetic system use?
norepinephrine
enteric
plexuses in the wall of the gut. some of these are shared with parasympathetic division. involuntary muscels
