Final Lecture Exam Flashcards
What are the different types on neurons
Multipolar (most common, in brain/spinal cord)
Bipolar (in retina)
Unipolar (sensory organs/spinal cord nerve)
Anaxonic (brain/helps in visual processes)
Describe axonal transport
2 way passage of proteins, organelles, and other material along an axon
Difference. Between anterograde and retrograde
Ante: movement down axon away from soma
Retro: movement up the axon to the soma
What do microtubules do
Guide materials along axon
What are the 6 diff glial cells
CNS: oligodendrocytes (form myelin sheath)
Ependymal cells (lines internal cavities, secrets cerebrospinal fluid)
Microglia (small, wandering macrophages formed by monocytes)
Astrocytes (supportive framework)
PNS: Schwann cells (envelope nerve fibers)
Satellite cells (surround neurosomas)
What are the differences between Schwann cells and oligodenrocytes
Schwann cells are in PNS, assist in regeneration of damaged nerve fibers and spirals repeatedly around a single nerve fiber, oligodenrocytes are in the CNS and form myelin sheaths anchored to multiple nerve fibers
What are nodes of Ranvier, internodes, and trigger zone
N.O.R.: gap between segments
Internodes: myelin covered segments from one gap to the next
Trigger Zone: the axon hillock and the initial segment (initiates nerve signal)
How do unmyelinated nerve fibers work
Travels up to 2 m/sec
How do myelinated nerve fibers work
Travels faster than unmyelinated
How do large nerve fibers work compared to small nerve fibers
Large work up to 120 m/sec while small work >/= 15 m/sec
What is the process of regeneration of nerve fibers
Needs regeneration tube in the PNS system
What is a regeneration tube
Formed by Schwann cells (PNS), basal lamina, and neurilemma near the injury
What is denervation atrophy
Muscle loss of nerve contact by damaged nerve
What are local potentials characteristics
Graded, decremental, reversible
What are action potentials characteristics
Follows an all or none law, nondecremental, irreversible
What is hyperpolization
When membrane potential becomes negative
What are the two types of refractory period and when do they occur
Absolute: from action potential to RMP
Relative: RMP to hyperpolarization
What is saltatory conduction
The never signal seem to jump from node to node
What are pre and post synaptic neurons
Pre: 1st neuron in signal path, contains synaptic vesicles that have the neurotransmitter
Post: 2nd neuron, constrains proteins that fxn as receptors and ligand regulated ion gates
What are the four major categories of neurotransmitters
- Acetylcholine
- Amino acid neurotransmitters
- Monoamines
- Neuropeptides
What are the embryonic derivations of CNS (start with forebrain, midbrain, hindbrain)
4th week they appear
5th week: forebrain divides into 2 (telencephalon/diencephalon), midbrain remains mescencephalon, hind brain divided into 2 (metencephalon/myelencephalon)
What’s the general structure of gray/white matter, Cortex, and corpus callusum
Gray: neuron cell bodies, dendrites, synapses, dull white
White: bundles of axons, lies deep to gray, pearly white
Cortex: made of gray matter, surface layer
Corpus Callosum: thick nerve bundle at bottom of longitudinal fissure
What is rostral and caudal
Rostral: toward forehead
Caudal: toward spinal cord
What are the layer of meninges and their distinctive features
- Dura mater: no epidural space, not attached to bone, layers separated by dura sinuses (outer periosteal: equivalent to periosteum of cranial bones, inner meningeal: continues into vertebral canal and forms dura sac around spinal cord)
- arachnoid mater: transparent membrane
- pia mater: very thin membrane that follows contours of brain
What is meningitis
Inflammation of the meninges
What is the number of ventricles and where are they
Two lateral: one in each cerebral hemisphere
Third: single narrow medial space beneath corpus callpsum
Fourth: small triangular changer between pons and cerebellum
What is the inerventricular foremen
Tiny pore that connects lateral ventricles to third ventricle
What is the choroid plexus
Spongy mass of blood capillaries on the floor of each ventricle
What is the cerebral aqueduct
Allows CSF to flow between third and fourth ventricle
What are the functions of the CSF
Buoyancy, protection, chemical stability
What is the blood brain Barrier
Protects blood capillaries throughout brain tissue
- consists of tight junctions between endothelial cells that form the capillary walls, astrocytes
What is the blood CSF barrier
Protects the brain at the choroid plexus
From rostral to caudal, what’s the order of the brain stem
Midbrain, pons, medulla oblongata
What are the 12 cranial nerves (name/#/fxn)
- Olfactory, sensory: smell
- Optic, sensory: vision
- Oculomotor, motor: turns eyeball, lid, iris, lens
- Trochlear, motor: eye movement (top)
- Trigeminal, both: sensory nerve of face
6.abducens, motor: eye movement (middle) - Facial, both: motor nerve of face
- Vestibulocochlear, sensory: hearing
- Glossopharyngeal, both: swallow, saliva, gagging, respiration
- Vagus, both: swallowing, speech, regulation of viscera
- Accessory, motor: swallowing, head, neck, shoulder movement
- Hypoglossal, motor: tongue for speech, swallowing, food manipulation
Where does an epidural take place and when is it given
In the dura mater (lumbar region) during labor
What is spina bifida
Congenital defect in which one or more vertebrae fail to form a complete vertebral arch for enclosure of spinal cord
How is white matter divided in the spinal cord
Columns/funiculi: 3 pairs of white matter bundles -posterior (dorsal) -lateral -anterior (ventral)
Tracts/fasciculi: subdivisions of each column
What are the ascending and descending tracts
Ascending: carry sensory info up the spinal cord
Descending: carry motor info down the spinal cord
What is endoneurium
Thin sleeve of loose connective tissue that surrounds EACH PNS nerve fiber
What is perineurium
Wraps fascicles in PNS
What is epineurium
Bundles numerous fascicles of PNS nerve (outermost layer)
How many spinal nerves are there
31
What is poliomyelitis
- Caused by poliovirus
- destroys motor neurons and anterior horn
- signs: muscle pain, weakness, loss of reflexes
- spreads by fecal contamination of water
What is ALS
- destruction of motor neurons and muscular atrophy and sclerosis
- scars spinal cord
- signs: difficulty speaking, swallowing, muscular weakness
- no cure
What are the layers in a nerve
Endoneurium
Perineum
Epineurium
What is posterior (dorsal) root
Sensory input to spinal cord
What is anterior (ventral) root
Motor output of spinal cord
What is posterior root ganglion
Contains somas of sensory neurons carrying signals to spinal cord
What are rootlets
6-8 in each root, attach to spinal cord and roots
What is the anterior and posterior ramus
Anterior: innervates the anterior and lateral skin and muscles of the trunk
Posterior: innervates the muscles and joints in that region of the spine and the skin of the back
What is the intervertebral foramen
Where the two roots (posterior/anterior) go through to form spinal nerve
What is threshold value
Value needed at trigger zone to form an action potential
What is a synapses
When end of axon meets its target cell
3 structures that make up the brain
Cerebrum, cerebellum, brain stem
What is the cerebellum fxn
Monitors muscle contractions and aids in motor coordination
