General Neuroanatomy & Neuronal Regeneration Flashcards
(32 cards)
The spinal cord at which vertebral levels has lateral horns? What is located here?
- from T1 - L2/L3
- the cell bodies of the preganglionic sympathetic fibers are located in these lateral/intermediate horns
- sympathetic innervation above T1 (ie, for neck and head) arises from the T1/T2 ganglia (they then ascend)
Name the major ascending and descending tracts of the spinal cord.
- ascending (afferent, sensory): dorsal column tract, lateral and anterior spinothalamic tracts, dorsal and anterior spinocerebellar tracts
- descending (efferent, somatic): lateral and anterior corticospinal tracts, rubrospinal tract, tectospinal tract, vestibulospinal tract, reticulospinal tract, septomarginal and interfascicular fasciculi (these are descending tracts found within the ascending dorsal column tract)
What is the thalamus? What are the five major nuclei that are found here? What info does each nucleus deal with?
- the thalamus is the major relay for all ascending sensory information EXCEPT for olfaction; it is part of the forebrain, located near the center of the brain, and has fibers projecting out to the cerebral cortex in all directions
- VPL (ventral posterolateral nucleus): pain, temperature, pressure, touch, vibration, proprioception
- VPM (ventral postermedial nucleus): facial sensation, taste
- LGN (lateral geniculate nucleus): vision
- MGN (medial geniculate nucleus): hearing
- VL (ventral lateral nucleus): motor
What is the limbic system? What structures are a part of it? What actions/roles is the limbic system responsible for?
- the limbic system is a collection of neural structures involved in emotion, long-term memory, olfaction, behavior modulation, and autonomic function
- structures: hippocampus, amygdala, fornix, mammillary bodies, cingulate gyrus
- responsible for the “Famous Five F’s”: feeding, fleeing, fighting, feeling, and fucking (sex)
What are the two parts of the forebrain? What does each contain?
- telencephalon: cerebral cortex, basal ganglia, hippocampus, amygdala, lateral ventricles
- diencephalon: thalamus and hypothalamus, 3rd ventricle
- (note that the forebrain is also called the prosencephalon)
What makes up the midbrain?
- mesencephalon: tectum, tegmentum, cerebral peduncles, cerebral aqueduct
What are the two parts that make up the hindbrain? What does each contain?
- metencephalon: pons and cerebellum, upper part of 4th ventricle
- myelencephalon: contains the medulla, lower part of 4th ventricle
- (note that the hindbrain is also called the rhombencephalon)
What’s the difference between spinal roots and spinal rami?
- the ventral (motor) and dorsal (sensory) spinal roots merge to form the spinal trunk, from which emerge (from the intervertebral foramina) the dorsal and ventral rami (these contain MIXED fibers!)
- the dorsal ramus carries motor and sensory fibers to/from the posterior, while the ventral ramus carries motor and sensory fiber to/from the anterior
- note that the ventral ramus is thicker than the dorsal ramus
Generally speaking, how many white columns are found on each half of the spinal cord?
- generally speaking, 3: dorsal, lateral, and ventral
- dorsal is strictly ascending, while lateral and ventral are ascending and descending
What are the basic general functions of each cerebral lobe?
- frontal: consciousness, motor control
- parietal: sensory, speech, taste, reading
- temporal: hearing, swallowing, auditory
- occipital: visual
At what spinal segment does the spinal cord terminate? At what segment does the subarachnoid space end?
- (at birth it ends at L3)
- in an adult, the spinal cord ends at L1/L2
- the SAS ends at S2
How many pairs of spinal nerves do we have?
- 31 pairs
- 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal
How many laminae zones are there in the spinal cord grey matter?
- 10 laminae
- laminae I - III are in the dorsal horn; they make up the substantia gelatinosa (2nd order neurons for nociception/pain)
- laminae IX is in the ventral horn; neurons here innervate skeletal muscle
Are spinal and cranial nerves part of the CNS or the PNS?
- they are a part of the PNS!
- EXCEPT, CN II (optic) is technically part of the CNS (it is myelinated by oligodendrocytes and is surrounded by the meninges)
- (CN I is also part of the CNS - it does it’s own thing)
What embryonic layer does the nervous system develop from?
- the ectoderm (forms the skin and nervous system)
- (mesoderm forms skeletal, muscular, and connective tissues; forms the microglia of the nervous system)
- (endoderm forms the alimentary, respiratory, and genitourinary tracts)
What are neural crests? What do they develop into?
- neural crests are groups of cells that lie dorsolaterally to the neural tube
- they develop into the sensory ganglia of the spinal and cranial nerves, as well as into the autonomic ganglia (they basically form the PNS and Schwann cells)
What embryonic structure develops into the dorsal horn of the spinal cord? What about the ventral horn?
- alar plate (dorsal plate) becomes the dorsal horn
- basal plate (ventral plate) becomes the ventral horn
What has developed by the 5th week of embryonic development? By the 7th week?
- by 5th week: the 3 primary brain vesicles are formed (prosencephalon, mesencephalon, and rhombencephalon)
- by 7th week: the 5 secondary brain vesicles are formed (telencephalon, diencephalon, mesencephalon, metencephalon, and myelencephalon)
What is the corpus callosum?
- corpus callosum is the bundle of commissural fibers that link corresponding regions of the 2 cerebral hemispheres
What basic functions are controlled by the brainstem?
- breathing, blood circulation, and consciousness
What’s the difference between tracts, commissural fibers, and association fibers?
- tracts ascend up and down
- commissural fibers move left and right, linking related centers on opposite hemispheres
- association fibers move forward and backward, linking centers on the same hemisphere
What general higher functions are associated with each cerebral lobe?
- frontal: executive function
- parietal: praxis
- temporal: memory
- occipital: perceptual and spatial function
- language involves an area made up by the inferior parietal lobe and superior temporal lobe
What is the basic role of the basal ganglia? What about of the cerebellum?
- basal ganglia: facilitation of appropriate movement and inhibition of unwanted movement
- cerebellum: generated movement is compared with sensory feedback for accurate and coordinated movements
Is damage to a neuron’s dendrites repairable? How about to a neuron’s axon? A neuron’s cell body?
- dendrites: usually repairable
- axon: can be slowly regrown in the PNS (not in the CNS because of its environment)
- cell body: irreparable (neuons are post-mitotic cells)
