nervous tissue
what is a neuron?
excitable cell: can be stimulated - generate, send, and receive nerve impulses
long-lived
high metabolic rate - needs oxygen and glucose
unable to divide
Describe gyri and sulci.
Gyri – folds on the brain for increased surface area and more neurons
Sulci – depressions between the gyri
name the two mnemonics relating to cranial nerves.
Oh once one takes the anatomy final very good vacations are heavenly
Some say marry money but my brother says big brains matter most
contents: CSF
remnant of embryonic neural canal
functions of CSF
Buoyancy
Physical cushioning
Nutrients and wastes
Environment
The two organizational divisions of the Nervous System.
What is Structural and functional organization?
Structural - CNS (Brain and spinal cord) and PNS (cranial nerves and spinal nerves)
Functional - somatic NS (voluntary) and autonomic NS (involuntary)
Describe the functions of different lobes.
Frontal - voluntary motor, concentration, decision making, and personality
Parietal - somatosensory association area (touch, pain, pressure, temp)
Temporal - auditory and olfactory (smell) centers
Occipital - primary visual cortex and visual association area
what is ptosis and what nerve does it affect?
ptosis: drooping of the eyelid
affects the abducent n. (CN VI); function: somatic motor to lateral rectus
what is the differences between the anterior and posterior horns?
anterior: motor neurons
posterior: sensory neurons
what does the diencephalon contain?
pineal gland: produces melatonin
thalamus: filter of sensory information
hypothalamus: autonomic and endocrine system master control, body temp regulation, emotional behavior control, emotional behavior control, food and water intake regulation, and circadian rhythms
Explain Glial cells. (function, location, and possible outcome)
Glial Cells – “glue” for the neurons. Assist neurons with physical protection, nourishment, and provide framework.
Outnumber neurons and are the cause of all tumors in nervous system.
Describe the function of the pre and post central gyrus.
Pre- central gyrus - motor homunculus
Post- central gyrus - somatosensory cortex. Conscious senses. Sensory homunculus.
describe cranial nerves
pass through cranial openings
sheath derived from cranial meninges
functions: varies (motor, sensory, and special sensory)
numbered based on origin from brain: 12 total
what are dermatomes?
segment of skin innervated by a spinal nerve
can be mapped
referred visceral pain sent to dermatome - organs and skin neurons in same ascending tract
example: myocardial infarction
what is the trigeminal nerve?
general sensory nerve to the head
3 branches: opthalmic, maxillary, and mandibular nerve
fibers: somatic motor fibers only in mandibular branch - muscles of mastication
The difference between unipolar, bipolar, and multipolar neurons.
Unipolar (pseudounipolar) – single short neuron process. Long axon. Sensory neuron. Cell bodies like the dorsal root ganglion in the spinal nerve
Bipolar – two processes from soma consisting of one dendrite and one axon. Normally found in special senses like retina.
Multipolar – most common neuron. Many dendrites with a single axon. Located near skeletal muscle. Example is motor neurons.
Describe the four functions of CSF.
CSF Functions – buoyancy of the brain, physical cushioning, removes nutrients and wastes, environment
-Made in the choroid plexus by astrocytes and capillaries
-Circulates in ventricles (lateral → third → aqueduct → fourth) then to arachnoid granulates.
-Hydrocephalus - abnormal accumulation of CSF on the brain and causes head to swell.
what is the special sensory nerve of hearing and equilibrium?
vestibulocochlear n (CN VIII)
explain the differences between the sympathetic and parasympathetic divisions?
sympathetic: prepares body for emergencies "fight or flight"
parasympathetic: brings body to homeostasis "rest and digest"
what are the three structures of the spinal cord?
conus medullaris: end of spinal cord
cauda equina: "horses tail" formed of nerve roots
filum terminale: anchors spinal cord to coccyx
5 components of a neuron
Soma - Cell body
Dendrites - Receive impulses, dynamic, often make new connections
Axons - Sends impulse away from soma, 1 per neuron, myelin Sheath covers axon; increases speed of impulse conduction
Synapse - Site at which neurons communicate through chemical messengers
Telodendria – terminal branches of the axon
Explain broca's area, wernickle's area, and the insula
Broca’s Area – motor speech area. Affects the laryngeal muscle and the muscle of the tongue. Located in the inferolateral portion of left frontal lobe
Wernickle’s Area – recognizing, understanding, and comprehending spoken language. Located on the left side of the parietal and temporal lobe.
Insula – primary gustatory cortex for taste. Emotional response and empathy
describe the vagus nerve
Cranial nerve 10
Origin: medulla oblongata
Follows carotid artery: Carotid sheath; Branches to pharynx, heart, bronchi, larynx
Esophageal plexus in thorax
Vagal trunks in abdomen: Stomach, small intestines, part of large intestines
Parasympathetic: Thoracic and abdominal viscera to left colic flexure
Muscles of pharynx and soft palate (gag reflex)
Taste from root of tongue
Visceral sensory in thorax and abdomen
why is there 2 motor neurons in the autonomic NS?
more connections
preganglionic: synapse with multiple post-ganglionic cells
postganglionic: synpase with multiple pre-ganglionic cells
what are the 4 plexus we discussed in lecture?
cervical: roots C1-C4, innervates anterior neck muscles and skin of neck, head, and shoulders
brachial: located in axilla, innervates upper limb and pectoral girdle
lumbar: roots L1-L4, innervates lower limb and inferior abdominal wall
sacral: anterior to sacrum in true pelvis, innervates gluteal region, pelvis, perineum, posterior thigh, leg, and foot