Exam 4 A&P Learning Outcomes

16-10: Summarize the effects of aging on the nervous system and give examples of interactions between the nervous system and other organ systems.

-Anatomical and physiological changes begin after maturity (age 30) -Accumulate over time -85 percent of people over age 65 have changes in mental performance and CNS function Common Age-related Anatomical Changes in the Nervous System -Reduction in Brain Size and Weight -Reduction in Number of Neurons -Decrease in Blood Flow to Brain -Changes in Synaptic Organization of Brain -Intracellular and Extracellular Changes in CNS Neurons Reduction in Brain Size and Weight -Decrease in volume of cerebral cortex -Narrower gyri and wider sulci -Larger subarachnoid space Reduction in Number of Neurons -Brain shrinkage linked to loss of cortical neurons -No neuronal loss in brain stem nuclei Decrease in Blood Flow to Brain -Arteriosclerosis -Fatty deposits in walls of blood vessels -Reduces blood flow through arteries -Increases chances of rupture -Cerebrovascular accident (CVA), or stroke -May damage surrounding neural tissue Changes in Synaptic Organization of Brain -Number of dendritic branches, spines, and interconnections decreases -Synaptic connections lost -Rate of neurotransmitter production declines

Functions of Parasympathetic Division

-Constriction of the pupils -To restrict the amount of light that enters the eyes: And focusing of the lenses of the eyes on nearby objects -Secretion by digestive glands: Including salivary glands, gastric glands, duodenal glands, intestinal glands, the pancreas (exocrine and endocrine), and the liver -Secretion of hormones: That promote the absorption and utilization of nutrients by peripheral cells -Changes in blood flow and glandular activity: Associated with sexual arousal -Increase in smooth muscle activity: Along the digestive tract -Stimulation and coordination of defecation -Contraction of the urinary bladder during urination -Constriction of the respiratory passageways -Reduction in heart rate and in the force of contraction

Internal Ear

-Contains fluid called endolymph -Bony labyrinth surrounds and protects membranous labyrinth Vestibule -Encloses saccule and utricle -Receptors provide sensations of gravity and linear acceleration Semicircular canals -Contain semicircular ducts -Receptors stimulated by rotation of head Cochlea -Contains cochlear duct (elongated portion of membranous labyrinth) -Receptors provide sense of hearing Round window -Thin, membranous partition -Separates perilymph from air spaces of middle ear Oval window -Formed of collagen fibers -Connected to base of stapes

Meningeal Layers

-Dura Mater: tough, fibrous, layer that forms the outermost covering of the spinal cord. -Arrachnoid Mater: middle meningeal layer. -Pia Mater: innermost meningeal layer consisting of meshwork of elastic and collagen fibers that is firmly bound to underlying neural tissue.

12-3: Describe the locations and functions of the various types of neuroglia.

-Ependymal Cells: Form epithelium called ependyma, Line central canal of spinal cord and ventricles of brain, Secrete cerebrospinal fluid (CSF), Have cilia or microvilli that circulate CSF, Monitor CSF, & Contain stem cells for repair -Astrocytes: Maintain blood-brain barrier (isolates CNS), Create three-dimensional framework for CNS, Repair damaged neural tissue, Guide neuron development, & Control interstitial environment -Oligodendrocytes: Myelination, Increases speed of action potentials, Myelin insulates myelinated axons, & Makes nerves appear white -Microglia: Migrate through neural tissue, Clean up cellular debris, waste products, and pathogens. -Schwann Cells: Neuroglia in PNS, surrounds all axons in PNS; responsible for myelination of peripheral axons; participate in repair process after injury. -Satellite Cells: Neuroglia found in PNS, surrounds ganglia; regulates environment around neurons in ganglia.

17-5: Describe the structures of the external, middle, and internal ear, explain their roles in equilibrium and hearing, and trace the for equilibrium and hearing to their destinations in the brain.

-External -Middle -Interal -Equilibrium & Hearing -Auditory Pathways

Essay #7: Identify the structural areas of the cerebral cortex and explain their functions.

-Frontal Lobe: primary motor cortex voluntary control of skeletal muscles. -Parietal Lobe: primary sensory cortex, conscious perception of touch, pressure, pain, vibration, taste, and temperature. -Temporal Lobe: auditory cortex and olfactory cortex conscious perception of auditory hearing and olfactory smell stimuli. -Occipital Lobe: visual cortex conscious perception of visual stimuli.

5. Compare and contrast graded potentials and action potentials.

-Graded potentials (local potentials) occur in the receptive (dendrites & cell bodies) due to opening of chemically gated channels that allow small ion amounts to cross the membrane and the altered charge may result in a change in polarization. Degree of change depends on how many molecules make it through and decreases intensity over distance-usually only lasting a short time. - Action potentials (AP) are the result of voltage gated channels opening (not chemically gated ones like GP's) and require a threshold value to be reached. Voltage below this is not sufficient to create an AP but once the threshold value is reached a temporary reversal of polarity across the plasma membrane occurs. AP's are self propagated or transmitted and maintain intensity along the synaptic knob because of the successive opening of other voltage gated channels. AP's obey the "all or none" law but not all APs have the same intensity under the same conditions.

Autonomic Tone

-Is an important aspect of ANS function -If nerve is inactive under normal conditions, can only increase activity -If nerve maintains background level of activity, can increase or decrease activity -Autonomic motor neurons: Maintain resting level of spontaneous activity & Background level of activation determines autonomic tone -Significant where dual innervation occurs: Two divisions have opposing effects -More important when dual innervation does not occur

16-7: Describe the hierarchy of interacting levels of control in the autonomic nervous system, including the significance of visceral reflexes.

-Lowest level regulatory control: Lower motor neurons of cranial and spinal visceral reflex arcs -Highest level: Pyramidal motor neurons of primary motor cortex & Operating with feedback from cerebellum and basal nuclei -Visceral Reflexes -Provide automatic motor responses -Can be modified, facilitated, or inhibited by higher centers, especially hypothalamus

16-4: Describe the structures and functions of the parasympathetic division of the autonomic nervous system.

-Organization -Functions

Organization and Anatomy of the Parasympathetic Division

-Parasympathetic preganglionic fibers leave brain as components of cranial nerves -III (oculomotor) -VII (facial) -IX (glossopharyngeal) -X (vagus) -Parasympathetic preganglionic fibers leave spinal cord at sacral level -Oculomotor, Facial, and Glossopharyngeal Nerves -Control visceral structures in head -Synapse in ciliary, pterygopalatine, submandibular, and otic ganglia -Short postganglionic fibers continue to their peripheral targets

Spinal Cord Essay #10: Identify the gross spinal cord structure and function.

-Posterior Median Sulcus: posterior dorsal surface of the spinal cord, shallow longitudinal groove. -Anterior Median Fissure: deeper groove along the anterior ventral surface. -Enlargements: expanded segments of gray matter dedicated to sensory and motor control of the limbs. -Cervical Enlargement: supplies nerves to the shoulder and upper limbs. -Lumbar Enlargement: provides innervation to structures of the pelvis and lower limbs. -Conus Medularis: inferior to the lumbar enlargement, where the spinal cord becomes tapered and conical. -Filum Terminale: slender strand of fibrous tissue extends from the inferior tip of the conus medullaris. -Dorsal Root Ganglia: contain cell bodies of sensory neurons. -Dorsal Roots: brings sensory information into spinal cord. -Ventral Roots: contain axons of motor neurons that extend into the periphery to control somatic and visceral effectors. -Spinal Nerve: sensory and motor roots are bound together into one. -Mixed Nerves: contains both afferent sensory and efferent motor fibers.

14-2: Explain how the brain is protected and supported, and discuss the formation, circulation, and function of cerebrospinal fluid.

-Protection -Support -Cerebrospinal Fluid

14-1:Name the major brain regions, vesicles, and ventricles, and describe the locations and functions of each.

-Regions -Vesicles -Ventricles

***14-8: Identify the main components of the limbic system, and specify the locations and functions of each.

-Relays information from mammillary body to cingulate gyrus Reticular formation -Stimulation or inhibition affects emotions (rage, fear, pain, sexual arousal, pleasure) -memory, drives, and motivation.

Receptor Affects

-Sensation The arriving information from these senses. -Perception: Conscious awareness of a sensation.

15-5: Describe the components, processes, and functions of the somatic motor pathways, and the levels of information processing involved in motor control.

-Somatic Motor Ways -Motor Control

13-4: Describe the major components of a spinal nerve, and relate the distribution pattern of spinal nerves to the regions they innervate.

-Spinal Nerves -Distribution Pattern of Spinal Nerves

Essay 15: Describe the components of a reflex arc.

-The wiring of a single reflex -Begins at receptor -Ends at peripheral effector -Generally opposes original or negative feedback

13-3: Explain the roles of white matter and gray matter in processing and relaying sensory information and motor commands.

-White Matter -Gray Matter

Regions Essay #8: Identify the major regions of the brain and describe their basic functions.

1. Cerebrum -Controls higher mental functions -Conscious thought processes, intellectual functions -Conscious and subconscious regulation of skeletal muscle contractions 2. Cerebrum -Neural cortex -Also called cerebral cortex -Folded surface increases surface area -Elevated ridges (gyri) -Shallow depressions (sulci) -Deep grooves (fissures) Cerebellum -Coordinates complex and repetitive somatic motor patterns -Adjusts output of other somatic motor centers in the brain and spinal cord 3. Diencephalon -Located under cerebrum and cerebellum -Links cerebrum with brain stem -Thalamus: Relays and processing centors for sensory information -Hypothalamus: Centers controling hormone production, emotion, & autonomic function. The Brain Stem -Processes information between: Spinal cord and cerebrum or cerebellum -Includes: Midbrain, Pons & Medulla oblongata 4. Midbrain -Processes visual and auditory data -Maintains consciousness -Generation of reflexive somatic motor responses. 5. Medulla Oblongata -Connects brain to spinal cord -Relays sensory information to thalamus and to the portions of the brain -Regulates autonomic functions: Heart rate, blood pressure, and digestion 6. Pons -Relays sensory information to cerebellum and thalamus -Subconcious somatic and visceral motor centers

External Ear

Auricle -Surrounds entrance to external acoustic meatus -Protects opening of canal -Provides directional sensitivity External acoustic meatus -Ends at tympanic membrane (eardrum) Tympanic membrane -Is a thin, semitransparent sheet -Separates external ear from middle ear Ceruminous glands -Integumentary glands along external acoustic meatus -Secrete waxy material (cerumen) -Keeps foreign objects out of tympanic membrane -Slows growth of microorganisms in external acoustic meatus

15-3: Identify the receptors for the general senses, and describe how they function.

Nociceptors -Are common: In the superficial portions of the s, joint capsules, Within the periostea of bones, & Around the walls of blood vessels -May be sensitive to: Temperature extremes, Mechanical damage, Dissolved chemicals, such as chemicals released by injured cells -Two types of axons - Type A and Type C fibers -Myelinated Type A fibers: Carry sensations of fast pain, or prickling pain, such as that caused by an injection or a deep cut, Sensations reach the CNS quickly and often trigger somatic reflexes, & Relayed to the primary sensory cortex and receive conscious attention. -Type C fibers: Carry sensations of slow pain, or burning and aching pain, Cause a generalized activation of the reticular formation and thalamus, & You become aware of the pain but only have a general idea of the area affected Thermoreceptors -Conducted along the same pathways that carry pain sensations -Sent to: The reticular formation, The thalamus, & The primary sensory cortex (to a lesser extent) Mechanoreceptors -Sensitive to stimuli that distort their plasma membranes -Contain mechanically gated ion channels whose gates open or close in response to: Stretching, Compression, Twisting, & Other distortions of the membrane Chemoreceptors -Respond only to water-soluble and lipid-soluble substances dissolved in surrounding fluid -Receptors exhibit peripheral adaptation over period of seconds: Central adaptation may also occur. -Receptors that monitor pH, carbon dioxide, and oxygen levels in arterial blood are located in:Carotid bodies. -Near the origin of the internal carotid arteries on each side of the neck: Aortic bodies. -Between the major branches of the aortic arch

14-10: Describe representative examples of cranial reflexes that produce somatic responses or visceral responses to specific stimuli. Essay# 13: Name and describe each of the 12 cranial nerves including type of nerve, area innervated, and basic function.

Olfactory Nerves (I) -Primary function: Special sensory (smell) -Olfactory Epithelium Optic Nerves (II) -Primary function: Special sensory (vision) -Retina of eye Oculomotor Nerves (III) -Primary function: Motor (eye movements) -Intrinsic eye muscles The Trochlear Nerves (IV) -Primary function: Motor (eye movements) -Superior oblique muscle The Trigeminal Nerves (V) -Primary function: Mixed (sensory and motor) to face -Jaw The Abducens Nerves (VI) -Primary function: Motor (eye movements) -Lateral Rectus Muscle The Facial Nerves (VII) -Primary function: Mixed (sensory and motor) to face -Tongue and glands The Vestibulocochlear Nerves (VIII) -Primary function: Sensory: Balance, equilibrium, and hearing. -Cochlea and Vestibule The Glossopharyngeal Nerves (IX) -Primary function: Mixed (sensory and motor) to head and neck -Tongue, Pharyngeal muscles and salivary gland The Vagus Nerves (X) -Primary function: Mixed (sensory and motor) Widely distributed in thorax and abdomen -Pharynx, external acoustic meatus, auricle, pharyngeal muscle The Accessory Nerves (XI) -Primary function: Motor to muscles of neck and upper back -Skeletal muscles of palate, pharynx, and larynx, sternocleidomastoid and trapezius The Hypoglossal Nerves (XII) -Primary function: Motor (tongue movements) -Tongue musclculature

17-4: Explain color and depth perception, describe how light stimulates the production of nerve impulses, and trace the visual pathways to their destinations in the brain. Essay #17: Describe the structure of the eyeball and the function of sight.

Photoreception -Photon strikes retinal portion of rhodopsin molecule embedded in membrane of disc -Opsin is activated -Bound retinal molecule has two possible configurations -11-cis form -11-trans form The Visual Pathways -Begin at photoreceptors -End at visual cortex of cerebral hemispheres -Message crosses two synapses before it heads toward brain -Photoreceptor to bipolar cell -Bipolar cell to ganglion cell Depth Perception -Obtained by comparing relative positions of objects between left-eye and right-eye images

16-1: Compare the organization of the autonomic nervous system with that of the somatic nervous system. 16: Explain the functions of the sympathetic and parasympathetic divisions of the ANS.

Somatic Nervous System (SNS) -Operates under conscious control -Seldom affects long-term survival -SNS controls skeletal muscles Autonomic Nervous System (ANS) -Operates without conscious instruction -ANS controls visceral effectors -Coordinates system functions -Cardiovascular, respiratory, digestive, urinary, reproductive Organization of the ANS -Integrative centers -For autonomic activity in hypothalamus -Neurons comparable to upper motor neurons in SNS -Operates largely outside our awareness -Has two divisions -Sympathetic division: Increases alertness, metabolic rate, and muscular abilities -Parasympathetic division: Reduces metabolic rate and promotes digestion

16-2: Describe the structures and functions of the sympathetic division of the autonomic nervous system.

Structure -Preganglionic neurons located between segments T1 and L2 of spinal cord -Ganglionic neurons in ganglia near vertebral column -Cell bodies of preganglionic neurons in lateral gray horns -Axons enter ventral roots of segments Functions -Increased alertness -Feelings of energy and euphoria -Change in breathing -Elevation in muscle tone -Mobilization of energy reserves

14-5: List the main components of the cerebellum, and specify the functions of each.

Structures of the Cerebellum -Folia: Surface of cerebellum & Highly folded neural cortex -Anterior and posterior lobes: Separated by primary fissure -Cerebellar hemispheres: Separated at midline by vermis -Vermis: Narrow band of cortex, Flocculonodular lobe & Below fourth ventricle -Purkinje cells: Receive input from up to 200,000 synapses & Relay information to Purkinje cells -The peduncles:( Superior, Middle, Inferior) Tracts link cerebellum with brain stem, cerebrum, and spinal cord

14-6: List the main components of the midbrain, and specify the functions of each.

Structures of the Midbrain -Tectum: Two pairs of sensory nuclei (corpora quadrigemina) -Superior colliculus (visual) -Inferior colliculus (auditory) -Tegmentum: Red nucleus (many blood vessels) & Substantia nigra (pigmented gray matter) -Cerebral peduncle: Nerve fiber bundles on ventrolateral surfaces & Contain: Descending fibers to cerebellum & Motor command fibers

17-2: Describe the sensory organs of taste, trace the gustatory pathways to their destinations in the brain, and explain the physiological basis of gustatory discrimination.

Taste Receptors (Gustatory Receptors) -Are distributed on tongue and portions of pharynx and larynx -Clustered into taste buds Taste Buds -Associated with epithelial projections (lingual papillae) on superior surface of tongue Four Types of Lingual Papillae 1. Filiform papillae -Provide friction -Do not contain taste buds 2. Fungiform papillae -Contain about five taste buds each 3. Vallate papillae -Contain 100 taste buds each 4. Foliate papillae

14-7: List the main components of the diencephalon, and specify the functions of each

Thalamus -Filters ascending sensory information for primary sensory cortex -Relays information between basal nuclei and cerebral cortex Epithalamus -Pineal Gland: Secretes melationin Hypothalamus -Provides subconscious control of skeletal muscle -Controls autonomic function -Coordinates activities of nervous and endocrine systems -Secretes hormones -Antidiuretic hormone (ADH) by supraoptic nucleus -Oxytocin (OT; OXT) by paraventricular nucleus -Produces emotions and behavioral drives:The feeding center (hunger) & The thirst center (thirst) -Coordinates voluntary and autonomic functions -Regulates body temperature: Preoptic area of hypothalamus -Controls circadian rhythms (day-night cycles): Suprachiasmatic nucleus

Brain Protection and Support Essay #9: Describe the structure and function of meninges, CSF, and the blood -brain barrier.

The Cranial Meninges -hold brain in place. Dura mater -Inner fibrous layer (meningeal layer) -Outer fibrous layer (periosteal layer) fused to periosteum -Venous sinuses between two layers Arachnoid mater -Covers brain -Contacts epithelial layer of dura mater -Subarachnoid space between arachnoid mater and pia mater Pia mater -Attached to brain surface by astrocytes

14-4: List the main components of the pons, and specify the functions of each.

The Pons -Sensory and motor nuclei of cranial nerves (V, VI, VII, VIII) -Nuclei involved with respiration -Apneustic center and pneumotaxic center: Modify respiratory rhythmicity center activity -Nuclei that process and relay information to and from cerebellum -Ascending, descending, and transverse tracts -Transverse fibers (axons): Link nuclei of pons with opposite cerebellar hemisphere

12-6: Discuss the factors that affect the speed with which action potentials are propagated.

Type A Fibers -Myelinated -Large diameter -High speed (140 m/sec) -Carry rapid information to/from CNS -For example, position, balance, touch, and motor impulses 12-6 Axon Diameter and Speed Type B Fibers -Myelinated -Medium diameter -Medium speed (18 m/sec) -Carry intermediate signals -For example, sensory information, peripheral effectors Type C Fibers -Unmyelinated -Small diameter -Slow speed (1 m/sec) -Carry slower information -For example, involuntary muscle, gland controls

15-1: Specify the components of the afferent and efferent divisions of the nervous system, and explain what is meant by the somatic nervous system.

-Afferent Division -Efferent Division

Middle Ear

-Also called tympanic cavity -Communicates with nasopharynx via auditory tube -Permits equalization of pressures on either side of tympanic membrane -Encloses and protects three auditory ossicles 1. Malleus (hammer) 2. Incus (anvil) 3. Stapes (stirrup)

16-9: Describe some of the ways in which the interactions of neurotransmitters influence brain function.

Brain Chemistry -Changes in normal balance between two or more neurotransmitters can profoundly affect brain function

14-3: Describe the anatomical differences between the medulla oblongata and the spinal cord, and identify the main components and functions of the medulla oblongata.

Brain-Medulla Oblongata-Spinal Cord The Medulla Oblongata -Allows brain and spinal cord to communicate -Coordinates complex autonomic reflexes -Controls visceral functions -Nuclei in the medulla -Autonomic nuclei control visceral activities -Sensory and motor nuclei of cranial nerves -Relay stations along sensory and motor pathways

12-4: Explain how the resting membrane potential is established and maintained.

• The Resting Potential -Because the plasma membrane is highly permeable to potassium ions: -The resting potential of approximately -70 mV is fairly close to -90 mV, the equilibrium potential for K+ -The electrochemical gradient for sodium ions is very large, but the membrane's permeability to these ions is very low -Na+ has only a small effect on the normal resting potential, making it just slightly less negative than the equilibrium potential for K+ 12-4 Membrane Potential -The sodium-potassium exchange pump ejects 3 Na+ ions for every 2 K+ ions that it brings into the cell -It serves to stabilize the resting potential when the ratio of Na+ entry to K+ loss through passive channels is 3:2 o At the normal resting potential, these passive and active mechanisms are in balance -The resting potential varies widely with the type of cell -A typical neuron has a resting potential of approximately -70 mV

Special Senses

-Are provided by special sensory receptors -Are located in sense organs such as the eye or ear -Are protected by surrounding tissues

14-9: Identify the major anatomical subdivisions and functions of the cerebrum, and discuss the origin and significance of the major types of brain waves seen in an electroencephalogram.

-Cerebrum Subdivisions -Brain Waves

Equilibrium Essay #20: Describe how we hear and maintain balance as well as the structures involved in those special senses.

-Sensations provided by receptors of vestibular complex -Hair cells: Basic receptors of inner ear & Provide information about direction and strength of mechanical stimuli Pathways for Equilibrium Sensations -Vestibular receptors: Activate sensory neurons of vestibular ganglia, Axons form vestibular branch of vestibulocochlear nerve (VIII), & Synapse within vestibular nuclei

Brain Waves

Alpha Waves -Found in healthy, awake adults at rest with eyes closed Beta Waves -Higher frequency -Found in adults concentrating or mentally stressed Theta Waves -Found in children -Found in intensely frustrated adults -May indicate brain disorder in adults Delta Waves -During sleep -Found in awake adults with brain damage

Motor Control

Conscious and Subconscious Motor Commands Control skeletal muscles by traveling over three integrated motor pathways -Corticospinal pathway -Medial pathway -Lateral pathway

16-5: Describe the mechanisms of parasympathetic neurotransmitter release and their effects on target organs and tissues.

Neuromuscular Junctions -All release ACh as neurotransmitter -Small, with narrow synaptic clefts -Effects of stimulation are short lived -Inactivated by acetylcholinesterase (AChE) at synapse -ACh is also inactivated by tissue cholinesterase in surrounding tissues

12-7: Describe the major types of neurotransmitters and neuromodulators, and discuss their effects on postsynaptic membranes.

Neurotransmitters -Norepinephrine (NE): Released by adrenergic synapses, Excitatory and depolarizing effect, & Widely distributed in brain and portions of ANS. -Dopamine: A CNS neurotransmitter, May be excitatory or inhibitory, & Involved in Parkinson's disease and cocaine use. -Serotonin: A CNS neurotransmitter & Affects attention and emotional states. -Gamma Aminobutyric Acid (GABA): Inhibitory effect, Functions in CNS, & Not well understood. Neuromodulators -Neuropeptides: bind to receptors and activate enzymes. -Opioids: in the CNS, Bind to the same receptors as opium or morphine, & Relieve pain.

Afferent Divsion

Receptors -Specialized cells that monitor specific conditions: In the body or external environment. -When stimulated, a receptor passes information to the CNS: In the form of action potentials along the axon of a sensory neuron. Sensory Neurons Sensory Pathways -Deliver somatic and visceral sensory information to their final destinations inside the CNS using: Nerves, Nuclei, & Tracts

12-6: Describe the structure of a synapse, and explain the mechanism involved in synaptic activity.

Synaptic Activity -Action potentials (nerve impulses) -Are transmitted from presynaptic neuron -To postsynaptic neuron (or other postsynaptic cell) -Across a synapse

Somatic Motor Ways

Always involve at least two motor neurons -Upper motor neuron -Lower motor neuron Upper Motor Neuron -Cell body lies in a CNS processing center -Synapses on the lower motor neuron -Innervates a single motor unit in a skeletal muscle -Activity in upper motor neuron may facilitate or inhibit lower motor neuron Lower Motor Neuron -Cell body lies in a nucleus of the brain stem or spinal cord -Triggers a contraction in innervated muscle -Only axon of lower motor neuron extends outside CNS -Destruction of or damage to lower motor neuron eliminates voluntary and reflex control over innervated motor unit

17-1: Describe the sensory organs of smell, trace the olfactory pathways to their destinations in the brain, and explain the physiological basis of olfactory discrimination. Essay #19:Describe the structures involved in the sense of smell and how it relates to function.

Olfactory Organs -Provide sense of smell -Located in nasal cavity on either side of nasal septum -Made up of two layers: Olfactory epithelium & Lamina propria Olfactory Discrimination -Can distinguish thousands of chemical stimuli -CNS interprets smells by the pattern of receptor activity

16-8: Explain how memories are created, stored, and recalled, and distinguish among the levels of consciousness and unconsciousness.

-How Memories are Created, Stored, and Recalled -Consciousness

White Matter

-Nuceli: -Sensory Nuceli: -Motor Nuceli: -Posterior Gray Horns: -Anterior Gray Horns: -Gray Commisures

13-1: Describe the basic structural and organizational characteristics of the nervous system.

Central Nervous System -Brain -Spinal Cord Peripheral Nervous System -Cranial Nerves -Spinal Nerves

Efferent Division

Nuclei, Motor Tract, & Motor Neurons -Controls peripheral effectors -Somatic motor commands travel from motor center in the brain along somatic motor pathways of the efferent division. -Neurons and pathways control skeletal muscles.

15-4: Identify the major sensory pathways, and explain how it is possible to distinguish among sensations that originate in different areas of the body

Somatic Sensory Pathways -Carry sensory information from the skin and musculature of the body wall, head, neck, and limbs -Three major somatic sensory pathways: The spinothalamic pathway, The posterior column pathway, & The spinocerebellar pathway

Ventricles

Third ventricle -Ventricle of the diencephalon -Lateral ventricles communicate with third ventricle: Via interventricular foramen (foramen of Monro) Fourth ventricle -Extends into medulla oblongata -Becomes continuous with central canal of the spinal cord -Connects with third ventricle: Via narrow canal in midbrain called the cerebral aqueduct

Vesicles

Three primary brain vesicles: neural tube -Prosencephalon -Mesencephalon -Rhombencephalon Five Secondary Brain Vesicles: Diencephalon and mesencephalon persist. -Telencephalon: Becomes cerebrum -Diencephalon -Mesencephalon -Metencephalon: Forms cerebellum and pons -Myelencephalon: Becomes medulla oblongata

Essay #18: Identify the structure of taste buds and how the sense of taste functions.

-Basal Cells -Gustatory Receptor Cells: extend taste hairs through taste pore. -Sweet, Salty, Sour, Bitter, & Water Receptors -Dissolved chemicals contact taste ahirs -Bind to receptor proteins of gustatory cells -Release of neurotransmitters by receptor cell

Gray Matter

-Columns -Posterior White Columns -Anterior White Columns -Anterior White Commisure: -Lateral White Column -Tract -Ascending Tracts -Descending Tracts

Distribution Pattern of Spinal Nerves

-Deratome: the specific bilateral region of the skin surface monitored by a single pair of spinal nerves. -Peripheral Neuropathies: regional losses of sensory and motor function most often resulting from from nerve trauma or compression.

16-6:Discuss the functional significance of dual innervation and autonomic tone.

-Dual Innervation -Autonomic Tone

Spinal Nerves Essay 12: Diagram the typical structure of a nerve.

-Epineurium: outermost layer consists of a dense network of collagen fibers. -Perineurium: the middle layer, fibers extend inward from the epineurium. -Endoneurium: the innermost layer, delicate connective tissue fibers, extend from the perineurium and surround individual axons.

15-2: Explain why receptors respond to specific stimuli, and how the organization of a receptor affects its sensitivity.

-Special Senses -Receptor Effects

13-2: Discuss the structure and functions of the spinal cord, and describe the three meningeal layers that surround the central nervous system.

-Spinal Cord -Meningeal Layers

17-3: Identify the internal and accessory structures of the eye, and explain the functions of each Essay #17: Describe the structure of the eyeball and the function of sight.

Accessory Structures of the Eye -Provide protection, lubrication, and support -Include: The palpebrae (eyelids), The superficial epithelium of eye & lacrimal apparatus Eyelids (Palpebrae) -The Continuation of skin -Blinking keeps surface of eye lubricated, free of dust and debris -Palpebral fissure: Gap that separates free margins of upper and lower eyelids -Medial canthus and lateral canthus: Where two eyelids are connected -Eyelashes: Robust hairs that prevent foreign matter from reaching surface of eye -Tarsal glands: Secrete lipid-rich product that helps keep eyelids from sticking together Superficial Epithelium of Eye -Lacrimal caruncle: Mass of soft tissue, Contains glands producing thick secretions, & Contributes to gritty deposits that appear after good night's sleep -Conjunctiva: Epithelium covering inner surfaces of eyelids (palpebral conjunctiva) and outer surface of eye (ocular conjunctiva) Lacrimal Apparatus -Produces, distributes, and removes tears -Fornix: Pocket where palpebral conjunctiva joins ocular conjunctiva -Lacrimal gland (tear gland): Secretions contain lysozyme, an antibacterial enzyme -Fibrous Layer Cornea Sclera -Vascular Layer: provides blood route, light regulation, creates aqueous humor, & controls shape of lens. Iris Pupil Ciliary Body Choroid -Inner Layer Rods Cones -Aqueous Humor: intraocular pressure helps keep eye pres

-How Memories are Created, Stored, and Recalled

Amygdaloid Body and Hippocampus -Are essential to memory consolidation -Damage may cause: -Inability to convert short-term memories to new long-term memories - Existing long-term memories remain intact and accessible Nucleus Basalis -Cerebral nucleus near diencephalon -Plays uncertain role in memory storage and retrieval -Tracts connect with hippocampus, amygdaloid body, and cerebral cortex -Damage changes emotional states, memory, and intellectual functions Cerebral Cortex -Stores long-term memories -Conscious motor and sensory memories referred to association areas -Occipital and temporal lobes -Special portions crucial to memories of faces, voices, and words -A specific neuron may be activated by combination of sensory stimuli associated with particular individual; called "grandmother cells" Cerebral Cortex -Visual association area -Auditory association area -Speech center -Frontal lobes -Related information stored in other locations -If storage area is damaged, memory will be incomplete

12-1: Describe the anatomical and functional divisions of the nervous system. The Central Nervous System (CNS)

Anatomical -Consists of the spinal cord and brain -neural tissue, connective tissues, and blood vessels Functional -Functions of the CNS are to process and coordinate -Sensory data from inside and outside body -Motor commands control activities of peripheral organs (e.g., skeletal muscles) -Higher functions of brain: intelligence, memory, learning, emotion

12-1: Describe the anatomical and functional divisions of the nervous system. The Peripheral Nervous System (PNS

Anatomical -Includes all neural tissue outside the CNS Functional -Deliver sensory information to the CNS -Carry motor commands to peripheral tissues and systems -Afferent: carries sensory info from PNS to CNS with receptors & effectors. -Efferent: Carries motor commands from CNS to PNS muscles and glands. Somatic Nervous System: voluntary & involuntary reflexes. Autonomic Nervous System: Sympathetic (stimulating fight or flight) & Parasympathetic (resting rest or digest)

Dual Innervation

Anatomy of Dual Innervation -Parasympathetic postganglionic fibers accompany cranial nerves to peripheral destinations -Sympathetic innervation reaches same structures: By traveling directly from superior cervical ganglia of sympathetic chain -Autonomic plexuses: Nerve networks in the thoracic and abdominopelvic cavities -Are formed by mingled sympathetic postganglionic fibers and parasympathetic preganglionic fibers: Travel with blood and lymphatic vessels that supply visceral organs.

16-3:* Describe the mechanisms of sympathetic neurotransmitter release and their effects on target organs and tissues.

Change activities of tissues and organs by: -Releasing NE at peripheral synapses -Target specific effectors, smooth muscle fibers in blood vessels of skin -Are activated in reflexes -Do not involve other visceral effectors -Distributing E and NE throughout body in bloodstream -Entire division responds (sympathetic activation) -Are controlled by sympathetic centers in hypothalamus -Effects are not limited to peripheral tissues -Alters CNS activity

Essay #6: Describe the components of a chemical synapse and how it functions.

Chemical Synapses - Specialized for release and reception of chemical neurotransmitters. -Make up the bulk of synapses. -Signal transmitted across a gap by chemical neurotransmitters. -Are found in most synapses between neurons and all synapses between neurons and other cells. -Cells not in direct contact -Action potential may or may not be propagated to postsynaptic cell, depending on: amount of neurotransmitter released & sensitivity of post synaptic cell.

Cerebrospinal Fluid Essay #9: Describe the structure and function of meninges, CSF, and the blood -brain barrier.

Circulation -From choroid plexus -Through ventricles -To central canal of spinal cord -Into subarachnoid space via two lateral apertures and one median aperture around the brain, spinal cord, and cauda equina Function -Surrounds all exposed surfaces of CNS -Interchanges with interstitial fluid of brain -Cushions delicate neural structures -Supports brain -Transports nutrients, chemical messengers, and waste products

Auditory Pathways

Cochlear branch -Formed by afferent fibers of spiral ganglion neurons -Enters medulla oblongata -Synapses at dorsal and ventral cochlear nuclei -Information crosses to opposite side of brain -Ascends to inferior colliculus of midbrain -Ascending auditory sensations -Synapse in medial geniculate nucleus of thalamus -Projection fibers deliver information to auditory cortex of temporal lobe

12-5: Describe the events involved in the generation and propagation of an action potential.

Continuous Propagation -Of action potentials along an unmyelinated axon -Affects one segment of axon at a time -Steps in propagation -Step 1: Action potential in segment 1: Depolarizes membrane to +30 mV & Local current. -Step 2: Depolarizes second segment to threshold &Second segment develops action potential. -Step 3: First segment enters refractory period -Step 4: Local current depolarizes next segment, Cycle repeats, & Action potential travels in one direction (1 m/sec) Saltatory Propagation -Action potential along myelinated axon -Faster and uses less energy than continuous propagation -Myelin insulates axon, prevents continuous propagation -Local current "jumps" from node to node -Depolarization occurs only at nodes

Consciousness

Deep sleep -Also called slow-wave or Non-REM (NREM) sleep -Entire body relaxes -Cerebral cortex activity minimal -Heart rate, blood pressure, respiratory rate, and energy utilization decline up to 30 percent Rapid eye movement (REM) sleep -Active dreaming occurs -Changes in blood pressure and respiratory rate -Less receptive to outside stimuli than in deep sleep -Muscle tone decreases markedly -Intense inhibition of somatic motor neurons -Eyes move rapidly as dream events unfold Nighttime sleep pattern -Alternates between levels -Begins in deep sleep -REM periods average 5 minutes in length; increase to 20 minutes over 8 hours

Cerebrum Subdivisions & Functions

Gyri of neural cortex -Increase surface area (number of cortical neurons) Insula ("island" of cortex) -Lies medial to lateral sulcus Longitudinal fissure -Separates cerebral hemispheres Lobes -Divisions of hemispheres Central sulcus divides: -Anterior frontal lobe from posterior parietal lobe Lateral sulcus divides: -Frontal lobe from temporal lobe Parieto-occipital sulcus divides: -Parietal lobe from occipital lobe

12-8: Discuss the interactions that enable information processing to occur in neural tissue.

Information Processing -At the simplest level (individual neurons) -Many dendrites receive neurotransmitter messages simultaneously -Some excitatory, some inhibitory -Net effect on axon hillock determines if action potential is produced

12-2: Sketch and label the structure of a typical neuron, describe the functions of each component, and classify neurons on the basis of their structure and function.

-Cell Body: contains nucleus, nucleolus, perikaryon, mitochondria, and ribosomes. -Dendrites: recieve information from other neurons. -Axon: carries electrical signal to target & critical for function. Motor Neurons -Carry instructions from CNS to PNS effectors through efferent fibers or axons -Somatic: skeletal muscles -Autonomic: smooth muscle, cardiac muscle, glands, and adipose tissue.

Essay 14: Define plexus and name the 4 major branches.

-Complex interwoven networks of nerve fibers & controls skeletal muscles of the neck & limbs. -Cervical -Brachial -Lumbar -Sacral