Exam 4 - CNS and PNS (Questions and Answers)

Basal Nuclei - ANSWER globus palidus, putamen and caudate nucleus. suppress unwanted movements and regulate muscle tone. Reticular formation - ANSWER netlike arrangement extending from lower part of diencephalon and i ...

Basal Nuclei - ANSWER globus palidus, putamen and caudate nucleus. suppress unwanted movements and regulate muscle tone. Reticular formation - ANSWER netlike arrangement extending from lower part of diencephalon and into upper spinal cord. filters incoming info. helps maintain consciousness Diencephalon - ANSWER most superior part of brain stem- contains the Thalamus, Hypothalamus and pineal gland and is the structural connection between cerebrum and brain stem. Thalamus - ANSWER Main relay station for sensory impulses to cerebral cortex and other parts of the CNS. Paired oval masses of gray matter joined by a bridge of intermediate mass crossing the 3rd ventricle. Assists in movement control, emotions, consciousness, pain perception,learning, memory and cognition. Hypothalamus - ANSWER a small part of the diencephalon inferior to the thalamus, and is composed of a dozen or so nuclei, including the mammillary bodies (relay stations for sense of smell), A major regulator of homeostatis, controlling temperature, water & food hunger/fullness, emotion and behavior (limbic), glucose level, and hormones with important connections to the pituitary gland. Cerebellum - ANSWER 2nd largest part of brain, accounts for 1/10th of brain mass, yet contains nearly half of the neurons in the brain. Cerebellum - ANSWER has 3 lobes - anterior lobe and posterior lobe governing subconscious aspects of skeletal muscle movement and the flocculonodular lobe in inferior contributing to equilibrium. Central area between two hemispheres is called the vermis. cerebellum - ANSWER Primary function is to evaluate how well movements initiated by motor areas in cerebrum are being carried out. Also is the main region regulating posture and balance., the "little brain" attached to the rear of the brainstem; it helps coordinate voluntary movement and balance. brain stem structures - ANSWER Midbrain - Corpora Quadrigemina containing 2 superior colliculi (visual reflex) and Inferior colliculi - auditory startle reflex; Pons, medulla oblongata Midbrain structures - ANSWER Corpora Quadrigemina - contains superior colliculi (visual reflex) and inferiro colliculi (auditory startle reflex) Pons structures - ANSWER contains the pneumotaxis and apneustic area, the nuclei in the pons works with medullary rhythmicity area of medulla Medulla Oblangata function - ANSWER contains several nuclei that control vital body functions. Regulates heartbeat, breathing rhythm, reflexes for coughing, vomiting, sneezing, hiccupping, and conscious proprioception. Nervous system functions - ANSWER 1. sensory- detect and relay stimuli thru afferent nerves; 2. Integrate process sensory info. 3. Motor function activating effectors - muscles and glands thru motor nerves. Divisions of Nervous system - ANSWER CNS - brain and spinal cord; 3 divisions of CNS - SNS; ANS and ENS; ANS is divided into autonomic neurons considered involuntary and the Sympathetic and Parasympathetic divisions Gray matter - ANSWER receives and integrates incoming and outgoing impulses, unmyelinated axons, cell bodies, and dendrites; found in horns and commissures of spinal cord; surrounds ventricles, in cortex, in nuclei of brain Anterior gray horns(gray matter) - ANSWER contains cell bodies of somatic motor neurons providing nerve impulses for skeletal muscles Lateral gray horns(gray matter) - ANSWER Contains cell bodies of autonomic motor neurons that regulate activity of cardiac, smooth muscle and glands. Posterior gray horns (gray matter) - ANSWER Contains interneurons ans well as axons of afferent sensory neurons. White matter - ANSWER Serves as highways for propagation of sensory input toward CNS and motor output toward effectors. Ascending tracts of white matter - ANSWER Posterior/dorsal columns contain afferent (sensory) fibers for limbs; Dorsal and ventral Spinocerebellar for unconsious proprioception, Lateral and ventral spinothalamic - sensing pain, warmth, cool, tickle, itch., carry sensory information toward brain Descending tracts of white matter - ANSWER Anterior Corticospinal - control muscles of trunk; Lateral Corticospinal control movements for precise, agile and highly skilled movement of hands and feet. Vestibulo spinal - equilibrium reflexes; tectospinal - auditory reflexes., convey motor commands into spinal chord Resting membrane potential - ANSWER -70 mV Threshold membrane potential - ANSWER -55 mV, The minimum potential shift at which an action potential is initiated (around -50mV usually). Depolarizing phase - ANSWER Inflow of sodium ions (Na+) causes depolarizing phase of action potential after membrane reaches a threshold level that is less negative than -70 which is -55 mV, Increase in Na+ permeability and reversal of membrane potential Repolarizing phase - ANSWER K+ flows out as K+ channels open and membrane starts to become repolarized, Decrease in Na+ permeability and an increase in K+ permeability Action potential generation - ANSWER Occurs when a stimulus depolarizes the membrane to threshold (-55 mV) Neurotransmitter - ANSWER A chemical released by the axon of a neuron in response to an action potential that binds to receptors on a postsynaptic cell and causes that cell to either depolarize slightlly (EPSP) or hyperpolarize slightly (IPSP). Examples are acetylcholine, norepinephrine, GABA, dopamine, and others. cholinergic synapses - ANSWER any synapse that releases ACh - acetylcholine -all neuromuscular junctions with skeletal muscle fibers -many synapses in CNS -all neuron-to-neuron synapses in PNS -all neuromuscular and neuroglandular junctions of ANS parasymphathetic division Adrenergic synapses - ANSWER release norepinephrine Usually released by a sympathetic post ganglionic sympathetic nerve fiber. Only exception post ganglionic sympathetic nerve fibers serving sweat glands which release ACh, and some blood vessels. Where is CSF found - ANSWER subarachnoid space brain and spinal cord within cavities and canals of brain and spinal cord Where is CSF generated - ANSWER choroid plexus in all brain ventricals How is CSF reabsorbed - ANSWER from subarachnoid space into blood by arachnoid villi at a rate of 20 mL/hr approx. or 480 ml/day reticular formation - ANSWER The region of the brain stem that alerts the cerebral cortex to incoming sensory signals and is responsible for maintaining consciousness and awakening from sleep. Diencephalon - ANSWER Part of the brain between the cerebral hemispheres and the midbrain, includes the thalamus, hypothalamus, and epithalamus Diencephalon - ANSWER located between the midbrain and the cerebrum and consists of the thalamus, hypothalamus, optic chiasma, and pineal body Thalamus - ANSWER The brain's sensory switchboard, located on the top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla Thalamus - ANSWER Serves as a sensory relay station by channeling all incoming sensory information to appropriate regions of the cortex for processing and back to appropriate muscles and organs in the body. Hypothalamus - ANSWER a neural structure lying below (hypo) the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion. Cerebellum - ANSWER brain structure that controls well-learned motor activities like riding a bike Corpus callosum - ANSWER large band of white neural fibers that connects to to brain hemispheres and carries messages between them; myelinated; involved in intelligence, consciousness, and self-awareness; doesn't reach full maturity until 20s brain stem - ANSWER the part of the brain that controls functions including heart rate, breathing, and body temperature; includes midbrain, pons, and medulla oblongata Basal Nuclei - ANSWER caudate, putamen, globus pallidus, important centers for motor coordination, acting as switches for impulses from other motor systems. Sciatic Nerve - ANSWER arises from the sacral plexus and passes about halfway down the thigh where it divides into the common peroneal and tibial nerves Muscle spindles - ANSWER lie parallel to the muscle fibers,detect changes in length and speed of length change, important for proprioception and motor learning Meninges - ANSWER Three connective tissue membrane layers that surround the brain and spinal cord. The three layers are dura mater, arachnoid layer, pia mater. The dura mater and arachnoid layer are separated by the subdural space. The arachnoid layer and pia mater are separated by the subarachnoid space. cranial nerves - ANSWER 12 pairs of nerves that start at the olfactory bulbs, thalmus visual cortex brainstem. They transmit info to from sensory organs of face & muscles of face, neck & upper shoulders and vagus X is the only nerve to continue lower in torso. Optic Nerve II - ANSWER Which cranial nerve is the nerve of sight? Trigeminal Nerve V - ANSWER the Largest of the Cranial Nerves, the single most important nerve in DENTISTRY, it has a MIXED function Olfactory Nerve I - ANSWER Comes directly from brain. Sensory only. Associated with limbic system. Forward extension of the brain. Function is smell. Abducens Nerve VI - ANSWER Lateral Rectus Muscle of Eye Accessory Nerve XI - ANSWER Sternocleidomastoid and Trapezius Muscles Trochlear Nerve IV - ANSWER Eye Movement - looking down and to the side Vestibulocochlear VIII - ANSWER The _____ nerve divides into two nerves. They are responsible for hearing and equilibrium. Hypoglossal nerve XII - ANSWER sensory and motor, primarliy motor, tongue movements for speech, chewing and manipulating food Vagus Nerve X - ANSWER CN. whole enchalada, huge nerve. sensory to pharynx, larynx, GI tract, heart, and tracheal/broncheal and motor primarily to soft palate, pharynx, larynx, trachea, GI, heart- often called "wandererers" head, thorax and abdominal cavity. Glossopharyngeal Nerves IX - ANSWER Contains motor fibers innervating through structures and sensory fibers transmitting taste stimuli in conjunction with cranial nerve VII Accessory nerves XI - ANSWER Motor to muscles of neck and upper back and actually arise from spinal cord C 1 thru C 5 traveling superiorly to enter skull before running to muscles they serve Facial Nerve VII - ANSWER Contains secretory fibers to the smaller salivary glands Anterior 2/3 of tongue and Secretory fibers lacrimal glands. Origin and course of Olfactory Nerve I - ANSWER fibers arise from olfactory epithelium and synapse in olfactory bulbs Origin and course of Optic Nerve II - ANSWER fibers arise from retina, crossing at the optic chiasma, to the thalamus, and to the visual cortex Origin and course of Oculomotor Nerve III - ANSWER fibers emerge at Dorsal midbrain and course ventrally to enter orbit, exiting skull thru orbital fissure Origin and course of Trochlear Nerve IV - ANSWER fibers emerge midbrain and exit from skull via superior orbital fissure Origin and course of Trigeminal V - ANSWER Fibers emerge from pons forming 3 divisions exiting separately from skull to mandibular, maxillary and opthalmic divisions Origin and course of Abducens VI - ANSWER Fibers leave inferior pons and exit via superior orbital fissure Origin and course of Facial VII - ANSWER Fibers leave pons and travel thru temporal bone via internal acoustic meatus exiting via stylomastoid foramen to reach face Origin and course of Vestibulocochlear VIII - ANSWER fibers run from inner ear housed in temporal bone, to enter pons Origin and course of Glossopharyngeal IX - ANSWER fibers emerge from medulla and leave skull via jugular foramen to run to throat Vagus X - origin and course - ANSWER Fibers emerge from the medulla pass thru jugular, descend thru neck, into thorax and abdomen Accessory XI - origin and course - ANSWER Fibers arise from superior aspect of spinal cord, enter skull, and then travel thru jugular foramen to reach muscles of neck and back Hypoglossal XII - origin and course - ANSWER Fibers arise from the medulla and exit skull via hypoglossal canal to travel to tongue