Self Study Flashcards
Central Nervous System
Brain
Spinal Cord
Peripheral Nervous System
Cranial Nerves
Spinal Nerves and Ganglia
Brain
Cerebral Cortex Limbic System Basal Ganglia Thalamus Hypothalamus Brainstem Cerebellum
Cerebral Cortex (Frontal, Parietal, Temporal, Occipital, Insular Lobes)
- initiates motor function
- receives and processes multisensory information,
- controls problem solving, complex thought, mood, memory, language
Limbic System
mood, emotion, aspects of memory
Basal Ganglia
regulate motor performance
Thalamus (Th):
relay center for predominately ascending pathways to the cerebral cortex
Hypothalamus (Hth)
regulates autonomic, endocrine and visceral functions
Brainstem (Midbrain, Pons, Medulla)
conduit between brain and head via cranial nerves as well as between brain and spinal cord, integrating center for brainstem reflexes, regulates arousal and awareness
Cerebellum
motor learning and coordination
Spinal Cord
The conduit of connections between brain and the Peripheral Nervous System and the integrating center for spinal reflexes
Afferent Neurons
carry nerve impulses from receptors or sense organs TOWARD the central nervous system
Efferent Neurons
Motor or effector neurons;
carry nerve impulses away from the CNS to effectors such as muscles or glands (and also the ciliated cells of the inner ear).
Dorsal roots
afferent pathways for fibers from varying peripherally located receptors
Where do dorsal roots terminate?
terminate (synapse) in the dorsal or ventral horns of the spinal cord to drive reflexes and participate in local circuits
Where do dorsal roots project?
project upstream to the brain either directly or via local relays with neurons that will project upstream.
Ventral roots
efferent fibers arising from ventral horn motor neurons
What do ventral roots contain?
preganglionic autonomic fibers at the thoracic (sympathetic) and sacral (parasympathetic) levels.
Deep tendon reflexes
cause a muscle to contract rapidly when stretched (e.g. by loading or tapping with a reflex hammer)
What happens during a deep tendon reflex?
- Muscle spindles activate the afferent fiber whose cell body is in the dorsal root ganglion (DRG)
- The central process of this pseudounipolar neuron sends its axon all the way to the ventral horn where it synapses on motor neurons that supply muscle fibers
How do the spinal nerves divide?
divide into dorsal (posterior) and ventral (anterior) rami
Dorsal rami from various spinal levels remain separate from each other and innervate __________vertebral column, the muscles of _________ and the overlying _____ in a _____ pattern.
Dorsal rami from various spinal levels remain separate from each other and innervate synovial joints of the vertebral column, the muscles of the deep back and the overlying skin in a segmental pattern.
Ventral Rami distributed to the ______ innervate ____ and _____ in a _____ pattern.
Ventral Rami distributed to the trunk also innervate skin and muscles in a segmental pattern.
What happens with ventral rami innervation of the limbs?
the majority of ventral rami merge with ventral rami of adjacent segments to form a plexus (brachial / lumbosacral)
Here their fibers (axons) intermingle and form multi-segmental peripheral nerves (e.g. the median nerve contains axons from ventral rami of C5, C6, C7,C8, and T1 and the femoral nerve contains axons from ventral rami of L2, L3, and L4).
What is gray matter (really pink matter due to rich blood supply, but who needs to be technical…)?
areas in the CNS consisting primarily of neuron cell bodies (and dendrites) clustered in various arrays
What are examples of gray matter?
- nuclei of the brainstem
- central gray matter of the spinal cord
- cortical layers of the cerebrum and cerebellum
The space surrounding the neuron cell bodies is occupied by _____ and ____ arrays that form _____ and establish connections between neurons.
The space surrounding the neuron cell bodies is occupied by dendrites and synaptic arrays that form local circuits and establish connections between neurons.
Nuclei
specific regions of gray matter where groups of neuron cells bodies are often functionally related.
Cortex
layered surface that covers some part of the CNS, specifically the external mantle of cerebrum and cerebellum
gyri of the cerebral cortex (and folia of the cerebellum)
sulci
fissures
bumps generated during development due to cells undergoing extensive expansion and folding of cortical surfaces to accommodate the increases in surface area
infoldings between gyri are called sulci
deeper grooves are called fissures
pathways and tracts
myelinated axons that generally have long trajectories
tracts
individual segment of a pathway that arises from a cell body in one location and terminates on a target in another location
structures containing tracts and fiber bundles in the CNS white matter are referred to as…
fasciculi (little bundles)
funiculi (strings)
peduncles (little feet), lemnisci (ribbons)
columns, or projections.
decussations
axon bundles that cross midline going from a location on one side to a different location on the contralateral side.
modality
the type of information being conveyed along a pathway.
refers to sensory pathways that show sensitivity to a particular stimulus based on the associated neuronal receptors
Peripheral Nervous System Motor
Output from the CNS
Somatic Motor Nerves
affect skeletal muscle function
Visceral Motor Neurons:
affect smooth and cardiac muscle function
Peripheral Nervous System Sensory
Input to the CNS
Somatic Sensory Nerves:
convey information about touch, pain, temperature, proprioception, stretch, etc. from the body
Visceral Sensory Nerves
convey sensory information (e.g. stretch, pressure, chemoreception) from organs
knee jerk reflex is an example…
deep tendon reflex
Damage to any of the elements of the deep tendon reflex pathway decreases…
the strength and/or speed of the reflex (hyporeflexia)
hyporeflexia useful for
one of the most useful signs in localizing dysfunction to a specific spinal or brainstem reflex pathway
decreased reflex may also be due…
to damage in the sensory or the motor components.
effect of damage to descending (corticospinal) pathways in the spinal cord, brainstem or brain (upper motor neurons) is…
increase the strength and speed of reflexes at lower segments (hyperreflexia)
hyperreflexia used to…
establish that the dysfunction is in the central nervous system
hyperreflexia delayed immediate effect
an absence or decrease in reflexes, an effect called spinal shock.
Myasthenia Gravis
weakness due to destruction of acetylcholine receptors at the neuromuscular junction
Selective Serotonin Reuptake Inhibitors (SSRIs) used to
treat depression by enhancing serotonin neurotransmission; prevents reuptake of serotonin from the synaptic cleft
