Nervous System Flashcards
Motor/efferent pathway controlling voluntary movement
Somatic Nervous System
Motor/efferent pathway controlling involuntary movement
Autonomic Nervous System
Division that regulates flight or fight response
Sympathetic Division
Division that regulates rest & digest
Parasympathetic Division
aka Cell Bodies or Perikarya
contains essential cellular components of the neuron
Soma
cell bodies in the PNS
Ganglion
cell bodies in the CNS
Nucleus
- transmits signals to other neurons
- covered in fatty myelin that speeds up transmission signals
Axons or Nerve Fibers
axons in the PNS
Nerve
axons in the CNS
Tracts
site where branches converge & co-mingle before being distributed
Nerve Plexus
receive signals from other neurons
Dendrites
sheath of living cells on the surface of PNS neurons that produces & maintains myelin
Neurillema
neurons with one primary process that branches out
Unipolar
neurons with two processes (dendrites + axon)
Bipolar
neurons with one axon + multiple dendrites
Multipolar
surrounds individual axons
Endoneurium
bundles of axons targeting the same location
Fascicles
surrounds each fasciculus
Perineurium
group of several fascicles supplied by the same blood vessels
Nerve
fibrous covering of a nerve
Epineurium
non-transmitting cells that support neurons
Neuroglia
phylogenetically oldest neuroglia that line the neurocoel (ventricles of the brain + central canal of the spinal cord) involved in the production of CSF
Ependymal Cells
deposit myelin on the surface of PNS axons
Schwann Cells
deposit myelin on the surface of CNS axons
Oligodendrocytes
- found between blood capillaries and neurons in the CNS
- maintain the blood-brain barrier by transferring nutrients from the bloodstream into the neuron and recycling neurotransmitters and ions
Astrocytes
remove cell debris, wastes, and pathogens via phagocytosis
Microglia
regulate nutrient and neurotransmitter levels around neurons in the PNS
Satellite Cells
centralization of complex responses in the front end of the nerve cord, resulting in a brain
Cephalization
- begins at the foramen magnum & continuous w/ the brain
- contained within the vertebral column
Spinal Cord
- exit through intervertebral foramina
- responsible for spinal reflexes & relaying info to & from the brain
Spinal Nerves
bundle of caudal vertebrae formed due to spinal cord being shorter
Cauda Equina
- part of spinal cord filled with cerebral spinal fluid
- remnant of neurocoel
Central Canal
- unmyelinated nuclei & dendrites
- found in interior in the spinal cord
- found in exterior of the brain
Gray Matter
where sensory neurons in the spinal cord emerge
Dorsal Horn
where visceral neurons in the spinal cord emerge
Lateral Horn
where motor neurons in the spinal cord emerge
Ventral Horn
- myelinated nerve fibers & neuroglia
- found in exterior in the spinal cord (divided into anterior, lateral & posterior funiculi)
- found in interior of the brain
White Matter
- axons that connect components of the CNS together
- may be primarily sensory or motor
Tracts
- connective tissue membranes on the outer glial membrane of the CNS
- continuous within spinal cord & brain
Meninges
- tough and dense fibrous outer membrane of meninges
Dura Mater
- filmy weblike membrane in the middle of meninges
- most vascularized meninx
Arachnoid
- inner membrane adhering to the glial membrane of the cord or brain
- attached to the arachnoid by a network of fibrous strands traversing a subarachnoid space filled with CSF
Pia Mater
- inner region composed of developing neural tube w/ actively mitotic cells forming neuroblasts and glioblasts
- eventually disappears
Ventricular zone / Germinal layer
- middle region of developing neural tube composed of cells proliferated from the germinal layer
- becomes gray matter
Intermediate zone / Mantle layer
- outer region of developing neural tube practically devoid of nuclei
- becomes white matter
Marginal zone
- groove along the lining of the central canal
- divides the intermediate zone into two plates
Sulcus Limitans
- dorsal to the sulcus limitans → dorsal horn (gray matter)
- gives rise to sensory neurons
Alar Plate
- ventral to the sulcus limitans → ventral horn (gray matter)
- gives rise to motor neurons
Basal Plate
union of spinal nerves that emerge from the dorsal/ventral horns & eventually unite
Spinal Roots
mostly or wholly sensory spinal roots
Dorsal Roots
purely motor spinal roots
Ventral Roots
bundle of cell bodies just proximal to emergence of the dorsal root
Dorsal Root Ganglia
supplies epaxial muscles & skin of the back
Dorsal Ramus
supplies hypaxial muscles & skin to the midventral raphe
Ventral Ramus
union of ventral rami
Spinal Nerve Plexuses
- composed of a gray and a white ramus
- connect the spinal nerves with the sympathetic ganglia in the trunk (thoracic & lumbar regions)
Ramus Communicans
spinal cord receives sensory signals and directly connects the sensory neuron to the effector motor neuron, so the brain does not need to process the signal for a response to occur
Spinal Reflexes
future Forebrain
Prosencephalon
develop into the Telencephalon
Telencephalic vesicles
develop into the Diencephalon
Optic vesicles
future Midbrain
Mesencephalon
- future Hindbrain
- composed of Myelencephalon & Metencephalon
Rhombencephalon
- fluid-filled cavities through which CSF flows
- continuous with the central canal of the spinal cord
Ventricles
modified ependymal cells that produce the CSF
Choroid Plexus
one-way valve that allows the flow of CSF from the subarachnoid space into the dural venous sinuses (blood) but prevents the backward flow of CSF if the fluid pressure is reversed
Arachnoid Villi
Medulla Oblongata (location)
in Myelencephalon
1) Houses primary nuclei of cranial nerves
2) Major route of ascending and descending pathways to and from higher centers of the brain
3) Contains centers for visceral, auditory, and proprioceptive reflexes (e.g. respiration, heartbeat, and intestinal motility)
Medulla Oblongata
Vagal lobes (location)
in Myelencephalon
- termination of incoming sensory fibers for taste
- in fishes: large swelling of the nucleus solitarus in the alar plate w/ taste buds over entire surface
Vagal lobes
Pyramidal Tracts (location)
in Myelencephalon
- corticospinal tracts that carry voluntary motor impulses from cerebral cortex to spinal cord
- in mammals: ventral ridges on myelencephalon
Pyramidal Tracts
cavity of hindbrain
Fourth Ventricle
Cerebellum (location)
in Metencephalon
- primary component of the roof of the hindbrain
1) Coordinates response of skeletal muscles to positional input from: - membranous labyrinth
- lateral-line canals
- proprioceptors
- motor centers in the brainstem and forebrain
2) ↑Size = ↑complexity of muscular activity
Cerebellum
Pons (location)
in Metencephalon
- enlargement of the amniote hindbrain floor
1) Formed by nuclei that convey info from cerebrum to the cerebellum
2) Contains a ventral decussation among mammals with large cerebellums
Pons
Tectum (location)
in Mesencephalon
roof of the mesencephalon
Tectum
- in Tectum
- reflex and relay centers receiving impulses from the retina
Optic Lobes / Superior Colliculi
- in Tectum
- caudal to the optic lobes
- reflex and relay centers receiving impulses from the inner ear and other sources
Auditory Lobes / Inferior Colliculi
optic + auditory lobes
Corpora quadrigemina
Tegmentum (location)
in Mesencephalon
- floor of the mesencephalon
- thickened by nuclei and aggregates of tracts connecting higher levels of the brain with the midbrain
Tegmentum
- in Tegmentum
- large mass of gray matter that participates in control of striated muscles
Red Nucleus
- in Tegmentum
- tracts that connect the cerebral cortex with the red nucleus
Cerebral peduncles
Cerebral aqueduct / aqueduct of Sylvius (location)
in Mesencephalon
canal that constricts the midbrain ventricle
Cerebral aqueduct / aqueduct of Sylvius
Epithalamus (location)
in Diencephalon
- dorsalmost component of Diencephalon
- roof of the third ventricle
Epithalamus
- in Epithalamus
- in lampreys: photoreceptors
- in gnathostomes: endocrine organ that responds to light
Pineal organ / Epiphysis
- in Epithalamus
- in Sphenodon: photosensitive organ
- in lizards: parietal eye
Parapineal Organ
- in Epithalamus
- elevations of a pair of underlying nuclei for olfaction
- carry impulses from olfactory nuclei, hypothalamus, forebrain nuclei to thalamus & forebrain
Habenulae
Thalamus (location)
in Diencephalon
- largest structure of the diencephalon
- walls of the third ventricle
- paired mass of multiple nuclei bulging dorsally behind the cerebral hemispheres
- where all ascending sensory pathways to the telencephalon synapse in before continuing to the telencephalon
Thalamus
- in Thalamus
- oval bridge of gray matter formed from large bulges of the left and right thalami into the third ventricle
Massa intermedia
Hypothalamus (location)
in Diencephalon
- floor and ventrolateral walls of the third ventricle
1) Homeostasis - major reflex control over the autonomic nervous system and the endocrine system
- contains receptors for monitoring the sodium chloride and glucose content in blood
- regulates appetite and internal temperature
2) Emotional Response - via connections with basal ganglia (limbic system)
3) Connection to Cerebellum - via inferior lobes
Hypothalamus
Pituitary / Hypophysis (location)
in Diencephalon
- bilobed endocrine gland: posterior neurohypophysis and anterior adenohypophysis
- connected to the hypothalamus via an infundibular stalk
Pituitary / Hypophysis
Optic chiasma (location)
in Diencephalon
ventral, cephalic boundary of the diencephalon where optic nerves reach the brain
Optic chiasma
Third ventricle (location)
in Diencephalon
- cavity of the diencephalon
- continuous with the cerebral aqueduct and the lateral ventricles of the cerebrum via the interventricular foramen
Third ventricle
Circle of Willis (location)
in Diencephalon
blood vessels supplying blood to the brain
Circle of Willis
Paraphysis (location)
in Telencephalon
- evagination of embryonic neurocoel that forms a wrinkled thin-walled sac between the diencephalon and the telencephalon
- only in amniotes except Sphenodon
Paraphysis
Olfactory Bulbs (location)
in Telencephalon
- extend forward from the hemispheres in contact w/ ethmoid cartilages/bones
1) Receive axon-like processes from olfactory cells in the epithelium
2) Transmit olfactory information to the cerebrum via olfactory tracts
Olfactory Bulbs
Lateral Ventricles (location)
in Telencephalon
- ventricles of the telencephalon, one in each hemisphere
- continuous with 3rd ventricle via interventricular foramen
Lateral Ventricles
- a perpendicular wall in mammals that separates the two interventricular foramina during embryonic development
Lamina terminalis
Cerebral Hemispheres (location)
in Telencephalon
folded to accommodate increased volume
Cerebral Hemispheres
rounded folds in the cerebral hemispheres
Gyri
grooves in the cerebral hemispheres that separate the gyri
Sulci
deep sulcus in the cerebral hemispheres
Fissure
interconnections of the left and right hemispheres, the most prominent of which is the corpus callosum
Commissures
dorsal region of the cerebrum
Pallium
receives small primary olfactory input and substantial auditory, lateral line, somatosensory, and visual inputs
Medial pallium
receive ascending input such as visual and auditory information from the thalamus
Dorsal & lateral pallium
ventral region of the cerebrum
Subpallium
- latero-ventral region of subpallium that are part of the basal ganglia, an assortment of nuclear groups at the base of the cerebral hemisphere
- controls sequence of actions in complex movements
Striatum
medial region of the subpallium that is an important part of the limbic system
Septum
have an inverted telencephalon
Ray-finned fish
- derived from the lateral wall of the pallium, increasing the size of the cerebrum
- receives visual, auditory, and somatic sensory stimuli and transmits information to the striatum and the rest of the pallium
- found in non-avian reptiles
Dorsal Ventricular Ridge (DVR)
- dorsal part of the DVR enlarged, giving rise to a larger forebrain
- found in birds
Wulst
- formed from enlargement of the dorsal pallium
1) center of somatic sensory processing (environmental awareness)
2) voluntary motor cortex that initiates voluntary motor activity
3) collates sensory info & stores as memory
Neocortex / cerebral cortex
4 lobes of the cerebral cortex/neocortex
Frontal, Parietal, Temporal, Occipital
massive band of white matter, connecting the neocortex with the brainstem
Internal Capsule
