A & P EXAM 4

Physiology of Equilibrium

Tilting of the head forward-sliding of the otolithic membrane bending the hair bundles-receptor potential -vestibular branch of the vestibulocochlear nerve

Plantar Reflex

Toes flex in response to downward motion on sole of foot Infants exhibit Babinski's sign, toes fan laterally

Arbor Vitae

Tracts of white matter

Paraplegia

Transection between T1-L1

Quadriplegia

Transection in cervical region

Cornea

Transparent coat over the iris Well supplied with nerve endings, especially nociceptors Excellant regeneration & repair capabilities No blood vessels = no immune function = easy transplants

3 Ways to classify sensory receptors

Type of stimulus Body location Structural complexity

Theta Waves

Uncommon in awake adults Emotional stress

Astigmatism

Unequal curvatures in different parts of the cornea or lens Treatment: cylidrically ground lenses or laser procedures

Hypogastric Plexus

Urinary Bladdar, genital organs

Visual Association Area

Uses past experiences to interpret stimuli (figuring out what something is)

Cholinergic Receptors: Nicotinic Receptors

Usually excitatory Found at NMJ, all postganglionic neurons So named because nicotine mimics action of ACh

Trigeminal Nerve

V Mixed Nerve Three Branches: Opthalmic, Maxillary, and Mandibular Deal with sensation of touch, pain, and temperature Motor axons supply muscles of mastication

Abducens Nerve

VI Motor Nerve Origin: Pons Cause abduction of the eyeball (lateral rotation)

Facial Nerve

VII Mixed Nerve Sensory Portion Extends from the taste buds of the anterior two-thirds of the tongue Motor Portion arises from the pons, innervates muscles of facial expression

Vestibulocochlear Nerve

VIII Sensory cranial nerve (limited motor function) Origin: Inner Ear Vestibular branch carries impulses for equilibrium Cochlear Branch carries impulses for hearing

Left Hemisphere

Verbal Logical, Analytical Rational Revieves somatic sensory signals from and controls muscles on right side of the body Reasoning Numerical and scientific skills Ability to use and understand sign language Spoken and written language

Order of Meninges/Spaces from superficial to deep

Vertebral Canal Epidural Space Dura Mater Subdural Space Arachnoid Mater Subarachnoid Space Pia Mater

Protective Structures of the Spinal Cord

Vertebral Column Meninges-spinal and cranial

Pain Perception

Warns of actual or impending tissue damage Strong motivation to take action Pressure and temp. extremes Chemicals from injured tissue (histamine, K+, ATP, acids, bradykinin) act on small diameter fibers Fibers release glutamate and substance P to activate second-order sensory neruons; ascend via spinothalamic tract Sharp pain- myelinated, small diameter Burning- Nonmyelinated C fibers Release gluatamate and substance P Pain supression by the brain- endorphins, enkephalins (inhibitory NT, halt pain signals)

Which substances easily cross BBB and diffuse into brain tissue?

Water, glucose, CO2, alcohol, most anesthetics

Optics & The Eye

We can see the visible light protion of the electromagnetic spectrum Visible light travels in packets of light called photons Photons travel in a wavelike manner When visible light passes through a prism, each component wave bends to a different degree

Optic disc

Weak spot, no sclera Blind spot- no photoreceptors (brain "fills in"

Diplopia

When external eye muscles are not perfectly coordinated, you cannot properly focus images, you see 2 images instead of 1

Effects of Gravity on Macula

When hairs bend toward the kinocilum, the hair cell depolarizes, exciting the nerve fiber, which generates more frequent action potentials When hairs bend away from the kinocilium, the hair cell hyperpolarizes, inhibiting the nerve fiber, and decreasing the action potential frequency

Sensory Tracts

White Matter Ascending toward the brain

Motor Tracts

White Matter Descending, carry impulses from the brain

Transverse (Commissural) Tracts

White Matter One side of the spinal cord to another

Vagus Nerve

X Mixed Nerve Sensory neurons deal with a variety of sensations such as proprioception, and stretching Most motor fibers are parasympathetic effectors Vagus means wandering Distributed from the head and neck into the thorax and abdomen Motor neruons arise from the medulla and supply muscles of the pharynx, larynx, and soft palate that are involved in swallowing and vocalization Regulates: Breathing, Heart Rate, Digestive system activity Transmit info from: Baroreceptors, Chemoreceptors, Taste Buds, Proprioreceptors

Accessory Nerve

XI Primarily Motor Nerve Emerges from the spinal cord, enters skull through foramen magnum Supplies sternocleidomastoid and trapezius muscles to coordinate head movements

Hypoglossal Nerve

XII Primarily motor Conduct nerve impulses for speech and swallowing

Autonomic Control

You can have autonomic reflexes too- a normal reflex arec is used with integration in the brain stem or spinal cord Direct innervation- brain stem and spinal cord Hypothalamus is the major control and integration center of the ANS

Cauda Equina

"horse's tail" Roots of lumbar, sacral, coccygeal nerves

Erb-Duchenne Palsy

"waiter's tip" Loss of sensation or paralysis along the lateral side to the arm Due to paralysis of upper brachial plexus

Celiac Plexus

(Largest) stomach, spleen, pancreas, liver, gall bladder, adrenal medullae

Pyramidal Pathways

...

Rubrospinal Tract

...

Spinocerebellar Pathway Dorsal column-medial lemniscal pathway

...

Spinothalamic Pathway

...

4 ways Preganglionic Neurons connect with Postganglionic Neurons

1) Axon may synapse with postgang. neurons in the ganglion it first reaches 2)Axon may ascend/descend to another ganglion before synapsing, forming sympathetic chains 3) Axon may continue through sympathetic ganglion (without synapsing, forming sympathetic chains) 4) Axon may pass through sympathetic trunk ganglion and prevertebral ganglion to synapse on chromaffin cells of adrenal medullae

Cerebellar Processing (4 Steps)

1) Cerebral cortex areas notify cerebellum of intent to initiate voluntary muscle contractions 2)Cerebellum receives information from body's proprioceptors to evaluate body position 3)Cerebellar cortex evaluates the best way to coordinate force, direction, extent of muscle contraction for a smooth, coordinated movement 4) Cerebellum sends "blueprint" for movement to cerebral motor cortex via superior peduncles Cerebellum is also able to monitor performance and send messages if necessary

Bleaching and Regeneration of Pigment

1) Isomerization of retinal 2) Trans-retinal separates from opsin (bleaching) 3) Retinal isomerase converts trans- to cis-retinal 4) Cis-retinal binds to opsin (regeneration)

Rhodopsin Formation & Breakdown

1) Pigment synthesis: 11-cis-retinal, derived from vitamin A, is combined with opsin to form rhodopsin 2) Pigement bleaching: light absorption by rhodopsin triggers a rapid series of steps in which retinal changes shape and eventually releases opsin 3) Pigment regeneration: Enzymes slowly convert all-trans-retinal to its 11-cis form in cells of the pigmented layer; requires ATP

Light Transduction Reaction Steps

1) Retinal absorbs light and changes shape, Visual pigment activated 2) Visual pigment activates transducin (G protein) 3) Transducin activates phosphodiesteras (PDE) 4) PDE converts cGMP into GMP , causing cGMP levels to fall 5) As cGMP levels fall, cGMP-gated cation channels close, resulting in hyperpolarization

Pathway of Sound Waves

1) Sound waves vibrate the tympanic membrane 2) Auditory ossicles vibrate. Pressure is amplified. 3) Pressure waves created by the stapes pushing on the oval window move through fluid in the scala vestibuli 4a) Sounds with frequencies below hearing travel through the helicotrema and do not excite hair cells 4b) Sounds in the hearing range go through the cochlear duct, vibrating the basilar membrane and the deflecting hairs on inner hair cells

CSF Circulation

1) The choroid plexus of each ventricle produces CSF 2) CSF flows through the ventricles and into the subarachnoid space via the median and lateral apertures 3) CSF flows through the subarachnoid space 4) CSF is absorbed into the dural venous sinuses via the arachnoid villi

Development of the Neural Tube

1) The neural plate forms from surface ectoderm. It then invaginates, forming the neural groove flanked by neural fold 2) Neural fold cells migrate to form the neural crest, which will form much of the PNS and many other structures 3) The neural groove becomes the neural tube, which will form CNS structures Surface Ectoderm forms neural plate-Neural groove flanked by neural fold-Neural fold cells form neural crest-neural groove becomes neural tube Spina bifida-failure for the posterior neural tube to close

In the dark steps

1) cGMP-gated channels open, allowing cation influx, Photoreceptor depolarizes 2) Voltage gated Ca2+ channels open in synaptic terminals 3) Neurotransmitter is released continuously 4) Neurotransmitter causes IPSPs in bipolar cell. Hyperpolarization results 5) Hyperpolarization closes voltage gated Ca2+ channels, inhibiting neurotransmitter release. 6) No EPSPs occur in ganglion cell 7) No action potentials occur along the optic nerve

In the light steps

1)cGMP-gated channels close, so cation influx stops. Photoreceptor hyperpolarizes. 2) Voltage-gated Ca2+ channels close in synaptic terminals 3) No neurotransmitter is released 4) Lack of IPSPs in bipolar cell results in depolarization 5) Depolarization opens voltage gated Ca2+ channels; neurotransmitter is released 6) EPSPs occur in ganglion cell 7) Action potentials propagate along the optic nerve

Processing of Sensory Input (6 Steps)

1. Sensory Receptors detect stimulus 2. Sensory Neurons send nerve impulses to spinal nerve to posterior root with 3 possible paths -Axons of sensory neruons extend into white matter and travel along a sensory tract -Axons of sensory neurons enter posterior gray horn to synapse with interneurons whose axons extend into white matter-sensory tract -Axons of sensory neurons may enter posterior gray horn to synapse with interneruons to synapse with motor neurons involved in reflex pathways 3. Sensory Input is processed in the brain (unless involved in the reflex path) 4. From the brain (or spinal cord, if a reflex path), motor output is sent from the spinal cord via somatic motor neurons of the anterior gray horn 5. Somatic Motor Neurons send nerve impulses through the anterior gray horn & root to enter spinal nerve to go to skeletal muscles 6. Motor Output from the spinal cord to cardiac muscle, smooth muscle, or glands involves autonomic motor neurons of lateral gray horn to anterior gray horn and root, to spinal cord

Sciatic Nerve

2 Nerves: Tibial and Common Fibular Muscular: Muscles of back of thigh, leg, foot Cutaneous: Skin of leg

Adaptation (receptor level)

A change in sensitivity (and therefore AP generation) in the presence of a constant stimulus Exhibited by many sensory receptors Phasic Receptors- fast adapting (lamellar and tactile corpusles) Tonic Receptors- little to no adaptation (nociceptors, proprioceptors)

Brain Stem: Reticular Formation

A netlike region of interspersed gray and white matter that extends through the brain stem Sensory information sent to the cerebral cortex, diencephalon, cerebellum

Sleep

A state of partial consciousness Aroused by stimulation Cortical activity suppressed, brain stem still active Most skeletal muscles are inhibited Suprachiasmatic nucleus of hypothalamus responsible for sleep patterns

Autonomic Tone

ANS Divison Balance between sympathetic and parasympathetic activity Generally, sympathetic division excites and parasympathetic division inhibits

Dual Innvervation

ANS division Most organs receive impulses from both sympathetic and parasympathetic divisions

Wernicke's Area

Ability to comprehend speech Only in the left hemisphere

Concussion

Abrupt, temporary loss of consciousness, vision & equilibrium disturbances, no obvious bruising

CSF Mechanical Protection

Absorbs shock, relieves weight of the brain

Asthma drugs

Activate B2 receptors to dilate bronchioles without activating B1 receptors which would increase heart rate

Glutamate & NMDA Receptor

Acts as a calcium channel Initiates cellular changes to bring about LTP

Phototransduction

After light is focused on the retina, photoreceptors start working Phototransduction-converting light energy into a graded receptor potential

Amyotrophic Lateral Sclerosis (ALS)

Aka Lou Gehrig's disease Neuromuscular condition Destroys ventral horn motor neurons Lose the ability to speak, swallow, breathe Death typically within 5 years Caused by environmental and genetic factors- excess extracellular glutamate causes excitotoxosis, autoimmune attack

Cerebrovascular Accident (CVA)

Aka Stroke Blood circulation stops, tissue dies Usually due to a blood clot

Clinical definition continuum of consciousness

Alertness Drowsiness/lethargy (proceeds to sleep) Stupor Coma

Amygdala

Allows us to respond to and display anger, avoidance, defensiveness, fear Promotes the release of adrenaline Yeah Amy's mad and is avoiding you

Reflex

An automatic, sudden, involuntary response to a stimulus When the integration takes place in the spinal cord, the reflex is a spinal reflex Can be inborn or learned Not clear-cut Inborn reflexes can be modified by learning and conscious effort

Development

Anterior end of the neural tube expands and forms primary brain vesicles-prosencepalon, Mesencephalon, rhombencephalon, Caudal end becomes the spinal cord

Atropine

Anticholinergic drug, blocks mACh receptors Given before surgery to dry up respiratory secretions & prevent salivation Causes pupil dilation

Neostimine

Anticholinesterase drug

Deafness

Any hearing loss Conduction deafness--something hampers sound conduction to the fluids of internal ear (ex. compacted earwax, ruptured eardrum) Sensorineural deafness-- damage to any neural structures between cochlear hair cells-auditory cortical cells

Reticular Activating System (RAS)

Ascending and descending functions Help maintain consciousness Aids in waking you from sleep Filters out repetitive stimuli (ex. feel of clothing) LSD interferes with sensory dampers, leading to sensory overload Inhibited by sleep centers, depressed by alcohol, sleep inducing drugs, & tranquilizers

Cerebellar Peduncles

Attach Cerebellum to the brain stem Ipsilateral fibers Superior Cerebellar Peduncles- deep cerebellar nuclei--cerebral motor cortex via thalamus Middle Cerebellar Peduncles- Pons--cerebellum (voluntary motor movement from motor cortex) Inferior Cerebellar Peduncles- Connect medulla and cerebellum; sensory info from proprioceptors and vestibular nuclei

Middle Ear

Auditory ossicles: malleus, incus, and stapes- transmit vibrations of eardrum to oval window, which moves internal ear fluids, tiny skeletal muscles contract reflexively during loud sounds to limit vibration and minimize damage to hearing receptors Oval window and round window Pharyngotympanic tube- aka auditory or eustachian tube, normally flat and closed, but opens when we yawn or swallow to equalize pressure (eardrum will only vibrate freely is pressures on either side are the same)

External (outer) Ear

Auricle (pinna)-funnels sound waves External auditory canal-extends from auricle-eardrum Tympanic Membrane- aka eardrum, boundary between external and middle ears, composed of connective tissue, transfers sound energy to auditory ossicles Ceruminous glands

Rami Communicantes

Autonomic (visceral) fibers, attach to ventral rami on thoracic cage

ANS Neurotransmitters & Receptors

Autonomic neurons are classified as cholinergic or adrenergic based on the NT they release Receptors are integral membrane proteins in the plasma membrane of the postsynaptic neuron or effector

Anatomy of the Autonomic Nervous System

Autonomic sensory neurons in organs and blood vessels-interoceptors Integrating centers in CNS Autonomic motor neurons propagate to effector tissues Usually operates without conscious control Controlled by hypothalamus and brain stem

Beta Waves

Awake and alert

Alpha Waves

Awake, but resting

Brachial Plexus Nerves

Axillary Musculocutaneous Radial Median Ulnar

Visual Pathway to the Brain

Axons of retinal ganglion cells Optic nerves Optic chiasma Optic tract- contain fibers from lateral aspect of ipsilateral eye and fibers from medial aspect of contralateral eye Carries all the information from the same half of the visual field Thalamus-lateral geniculate nuclei Optic Radiation- axons from thalamic neurons to cerebral white matter Primary visual cortex-occipital lobe Some branches to the midbrain- Superior colliculi, pretectal nuclei, hypothalamus-suprachiasmatic nucleus

Tourette's Syndrome

Basal Nuclei Disorder Coprolalia (excessive explitives), echolalia (echoing what is said), echopraxia (echoing movements), motor and verbal ticks (saying or doing the same thing over and over again)

Huntington's Chorea

Basal Nuclei Disorder Patients are unable to restrain movements (like choreography) Autosomal dominant (if you get the chromosome, you have a 100% chance of having the disease) Cell death in the striatum (caudate nucleus & putamen)

From the Cochlea to the Auditory Cortex

Basilar membrane moves up and down, and the stereocilia of the hair cells embedded in the tectorial membrane bend Then nerve impulses begin in the cochlear nerve and travel to the brain When they reach the auditory cortex in the temporal lobe, they are interpreted as a sound Each part of the spiral organ is sensitive to different wave frequencies, or pitch

Posterior segment

Behind the lens Filled with vitreous humor- transmits light, supports posterior surface of lens, holds layers of retina together, contributes to intraocular pressure, formed in the embryo and lasts a lifetime

Lens

Biconvex, transparent, flexible Lacks blood vessels Held in place by ciliary zonule Consists of a capsule with proteins (crystallins) Enlarges throughout life as new fibers added- becomes denser, less elastic, more difficult to focus

Adrengergic Receptors

Bind NE and E (epinephrine, aka adrenaline) NE can be released as a NT, or as a hormone in the blood E is released as a hormone 2 types: Alpha and Beta receptors NE is removed from cleft by reuptake or inactivated enzymatically by COMT or MAO

Antagonist

Binds to and activates a receptor Ex. Propranolol is a beta blocker that prevents activation by NE and E, resulting in decreased heart rate, and therefore, decreased blood pressure

Agonist

Binds to and activates a receptor Ex. Phenylephrine at alpha-1 receptors constricts blood vessels in nasal mucosa

Vascular System

Blood vessels Vasomotor tone- innervated by sympathetic fibers that keep blood vessels partially contracted all the time (can adjust amount of constriction) A- blockers- block vasomotor fibers, treats hypertension

Internal ear (labyrinth)

Bony labyrinth-cavity, filled with perilymph, vestibule- contain euilibrium receptors (maculae)-- saccule, utricle Semicircular canals-contail equilibrium receptors Membranous labyrinth- membranes and ducts inside the body labyrinth, suspended in perilymph, interior contains endolymph, semicircular ducts

Midbrain

Brain Stem Extends from the pons to the diencephalon Cerebral Aqueduct found here (connects 3rd and 4th ventricles) Cerebral Peduncles(definition on next card) Corpora Quadrigemina (next card) Contains cranial nerves III-IV

Pons

Brain Stem Lies superiorly to the medulla, anterior to the cerebellum Acts as a bridge that connects different parts of the brain Consists of nuclei, sensory tracts, and motor tracts Contain centers that control breathing CN V-VII If you are in a pond you can't breathe..duh

Medulla Oblongata

Brain Stem White matter contains all sensory/ascending tracts and motor/descending tracts between the spinal cord and the rest of the brain Pyramids- Bulges of Pyramidal (corticospinal) white matter tracts Decussation of the pyramids- 90% of axons in the pyramids cross over to the other side (each side of the brain controls voluntary movement on the opposite side of the body) The Medulla contains nuclei associated with CN 8-12 4th ventricle is found here

Brain Blood Flow

Brain represents only 2% of total body weight, but recieves approx. 20% of the total blood supply

Contusion

Bruising due to trauma, includes blood leakage, loss of consciousness, loss of reflexes, cessation of respiration (but stabilized for a few seconds)

Root

Bundle of axons, connect each spinal nerve to a segment of the cord Posterior (dorsal) root- sensory axons Dorsal root ganglion- cell bodies of sensory neurons Anterior (ventral) root- motor axons

Hydrocephalus

CSF accumulates in the ventricles and does not drain properly This increased pressure can damage nervous tissue, and causes swelling the brain Usually due to a blockage in the cerebral aqueduct Can also be caused by a pineal tumor, bacterial infection, or inflammation

Medulla Oblongata has nuclei that regulate which body functions?

Cardiovascular Center Respiratory Center Vomiting Center Degultition Center Sneezing Coughing Hiccupping

Motor (efferent) nerves

Carry impulses away from CNS

Sensory (afferent) nerves

Carry impulses toward CNS

Mixed Nerves

Carry sensory and motor fibers Transmit to and from CNS Most nerves are mixed

Bell's Palsy

Cause: Partial inflammation of facial nerve Paralysis of facial muscles, partial loss of taste sensation Lower eyelid droops, corner of mouth sags- difficult to eat or speak normally Treatment: Corticosteroids Recovery is complete in 70% of cases

The Stretch Reflex

Causes contraction of a skeletal muscle in response to stretching of the muscle Monosynaptic reflex Ipsilateral Patellar or knee-jerk reflex: stretching of a muscle-> activation of muscle spindles-> sensory neuron-> spinal cord-> motor neuron-> muscle contraction Positive knee jerk test proves sensory and motor connections between muscle and spinal cord are intact Vigor of response indicates degree of excitability of spinal cord

Ventricles

Central cavity enlarges to become 4 ventricles Filled with CSF and lined with ependymal cells Lateral ventricles separated by septum pellucidum CSF in 4th ventricle connected with CSF in subarachnoid space via lateral (2) and medial (1) apertures

Cerebellar Cortex

Cerebellum Highly folded gray matter called folia increases surface area

Purkinje Cells

Cerebellum Large neurons, extensively branched dendrites The only cortical neurons that send axons through white matter to synapse with the central nuclei of the cerebellum

What are the 3 regions of the Cerebrum?

Cerebral Cortex (Gray Matter) Internal White Matter Basal Nuceli (islands of gray matter, located deep within white matter)

Anterior Association Area

Cerebral Cortex: Association Area Aka prefrontal cortex Intellect, complex learning, recall, personality Develops slowly in children Persons with lesions in this area: oblivious to social restraints, careless with personal appearance, loss of judgement/attentiveness/inhibition

Limbic Association Area

Cerebral Cortex: Association Area Includes Cingulate gyrus, Parahippocampal gyrus, Hippocampus Provides emotional impact Establishes memories

Posterior Association Areas

Cerebral Cortex: Association Area Recognizing patterns & faces Awareness of self and surroundings in space Understanding of written & spoken language Someone with lesions in this area may refuse to wash or dress the side of the body opposite lesion because "that does not belong to me"

Premotor Cortex

Cerebral Cortex: Motor Areas Anterior to the precentral gyrus Helps PLAN movements-staging area for skilled motor activities Sequences basic movements into complex tasks (playing music, typing) Controls voluntary actions that depend on sensory feedback Supplies about 15% of pyramidal tract fibers

Broca's Area

Cerebral Cortex: Motor Areas Present in ONE hemisphere only Motor speech area-directs muscles involved in speech production

Primary Motor Cortex

Cerebral Cortex: Motor Areas Pyramidal cells allow us to consciously and precisely control voluntary skeletal muscle movements - Long axons-- pyramidal/Corticospinal tract Body is represented spatially in the primary motor cortex of each hemisphere (somatotopy-mapping of the body in CNS, motor homunculus-"little man", contralateral control)

Visceral Sensory Area

Cerebral Cortex: Sensory Area Conscious perception of visceral sensations, this includes lungs

Olfactory Cortex

Cerebral Cortex: Sensory Area Located at piriform lobe within temporal lobe Afferent fibers from nasal cavities send impulses along olfactory tracts Smell

Gustatory Cortex

Cerebral Cortex: Sensory Area Perceive taste stimuli

Vestibular Cortex

Cerebral Cortex: Sensory Areas Conscious awareness of balance

Visual Area

Cerebral Cortex: Sensory Areas Occipital Lobe (largest cortical sensory area) Primary visual cortex Visual association area

Auditory Area

Cerebral Cortex: Sensory Areas Temporal Lobe (houses the internal and external meatuses) Memories of sounds are stored for reference Wernicke's area

Projection Fibers/tracts

Cerebral White Matter Conduct nerve impulses back and forth from cerebrum to lower parts of CNS

Association fibers/tracts

Cerebral White Matter Conduct nerve impulses between gyri in the SAME hemisphere

Commissural Fibers/tracts

Cerebral White Matter Conduct nerve impulses from gyri in one hemisphere to corresponding gyri in the other hemisphere Ex.-Corpus Callosum, anterior commissure, posterior commissure

Amputation

Cerebral cortex is still wired for sensory for hand (phantom sensations) Other sites can claim what was taken away

Basal Nuceli

Cerebrum Three nuclei deep within each cerebral hemisphere make up the basal ganglia Consists of- Globus Pallidus, Putamen, Caudate Nucleus Functions- Help initiate and terminate movements, Suppress unwanted movements, Regulate muscle tone

Enlargements of Spinal Cord

Cervial (C4-T1) Lumbar (T9-T12)

Cerebrospinal Fluid (CSF)

Clear fluid, secreted by ependymal cells in the ventricles and central canal Circulates through ventricles, spinal cord (central canal) & subarachnoid space Absorbs shock Protects brain and spinal cord Nutrient and waste exchange

Near point

Clostest point on which we can clearly focus

Cataracts

Clouding of the lens World appears distorted (like frosted glass) Lens transplant Usually age related, or due to smoking, diabetes, mellitus, or excessive exposure to intense sunlight

Vascular layer: Iris

Colored part of eye Pupil-central opening, allows light to enter eye Muscle fibers change pupil size Sphincter pupillae- constrict pupil, parasympathetic innervation Dilator pupillae- radial muscles, dilate pupil, sympathetic innervation

Hippocampus

Communicates with the prefrontal area of the brain Learning, memory, spatial navigation Hippos are really smart and because they are so big they navigate through space

Limbic System

Complex network of tracts and nuclei-incorporates portions of the cerebral lobes, the basal nuclei, and the diencephalon Blends primitive emotions (fear, aggression, pleasure) with higher mental functions (reasoning, memory)- why emotions sometimes override logic; why reason can stop us from inappropriately expressing emotions Connections between limbic system and other brain regions allow for integration "Emotional Brain" as it governs emotional aspects of behavior Also involved in olfaction and memory Passes through hypothalamus along with ANS information (psychosomatic illness) Interacts with prefrontal areas- react emotionally to things consciously understood, consciously aware of the emotional richness of life

Strabismus

Congenital weakness of external eye muscles Affected eye rotates medially or laterally Eyes alternate focusing on objects, but eventually input from weaker eye is disregarded by the brain Treatment: Patch the strong eye, may need surgery

Corpus Callosum

Connects the right and left Cerebral Hemispheres internally White matter

Definition of Consciousness

Conscious perception of sensations, voluntary initiation, control of movement, higher mental processing capability

Sacral Parasympathetic Outflow

Consists of S2-S4 Pelvic Splanchnic nerves

A1

Constricts blood vessels and visceral organ sphincters, dilates pupils

White Rami Communicantes

Contain sympathetic preganglionic axons Connect the anterior ramus of the spinal nerve with the ganglia of the sympathetic trunk

Responses of the Pupil to Light

Contraction of the circular muscles of the iris causes constriction of the pupil Contraction of the radial muscles causes dilation of the pupil

Each hemisphere deals with sensory/motor functions of _______ side of body

Contralateral

Spinal Cord

Contributes to homeostasis by providing quick, reflexive responses to many stimuli Spinal cord is the pathway for sensory input to the brain and motor output from the brain

Functions of the Hypothalamus

Control of the ANS- main visceral control center Production of hormones Regulation of: emotional and behavioral patterns, eating and drinking, water balance and thirst, body temperature, circadian rhythms The "real" Master Gland (because it controls the Pituitary Gland) Like a pregnant woman

Anterior and Posterior Lobes of the Cerebellum

Control subconscious aspects of skeletal movement

Cerebral Cortex: Motor Areas

Control voluntary movement Located in posterior part of frontal lobes Primary (somatic) motor cortex Premotor Cortex Broca's area

Cerebrum

Controls the conscious mind Motor and sensory functions are localized in discrete areas Higher mental functions are spread over large areas

Frontal Eye Field

Controls voluntary movement of the eyes

Functions of the Cerebellum

Coordinate movements Regulate posture Balance Compares intended movements with executed movements Only 10% of brain mass, but takes almost 50% of the neurons in the brain The "gymnast"

Pathway of light

Cornea Aqueous humor Lens Vitreous humor Neural layer of retina Photoreceptors

Dura Mater

Cranial meninges Falx Cerebri, Falx Cerebelli, Tentorium Cerebelli

Which substances cannot cross the BBB?

Creatine, urea, ions, proteins, antibiotics

Semicircular Ducts

Crista, a small elevation in the ampulla contain hair cells and supporting cells Cupula, a mass of gleatinous material covering the crista Head movement-semicircular ducts and hair cells move with it- hair bundles bend-receptor potential-nerve impulses-vestibular branch of the vestibulochlear nerve

Categories of Memory (4)

Declarative (fact) memory Nondeclarative Memory- Procedural skills memory (piano playing); Motor Memory (riding a bike); Emotional Memory

Parkinson Disease

Degeneration of dopaminergic neurons in substantia nigra Dopamine-deprived basal nuclei become overactive, leading to "pill-rolling" movements, shuffling gait Treatment: L-dopa, but becomes ineffective as degeneration progresses Michael J. Fox

Age-related macular disease (macular degeneration)

Degenerative disorder of the retina Peripheral vision intact, central vision blurred No effective treatment

Somatosensory Organization: Circuit Level

Deliver impulses to cerebral cortex for localization and perception Different ascending pathways carry different types of information to different places in the brain

Gravitational Equilibrium Pathway

Depends on utricle and saccule Utricle is sensitive to horizontal movements of the head Saccule is sensitive to vertical movements of the head Both contain hair cells with stereocilia embedded in an otolithic membrane Large central cilium called the kinetocilium Calcium carbonate granules (otoliths) rest on otolithic membrane When head or body moves in horizontal or vertical plane the otoliths are displaced and the otolithic membrane sags, bending stereocilia

Thalamus

Diencepalon Composed of oval masses of gray matter organized into nuclei Major relay station for most sensory outputs Mediates sensation, motor activities, cortical arousal, learning, memory

Hypothalamus (anatomy)

Diencepalon Inferior to the thalamus Consists of the mammillary body (olfaction), median eminence, infundibulum, and a number of nuclei

Epithalamus/Pineal Gland

Diencepalon Small region superior to the thalamus Secretes Melatonin which induces sleep, helps set circadian rhythms, stimulated by the suprachiasmatic nucleus of the hypothalamus

B2 Receptor

Dilates blood vessels and bronchioles, relaxes smooth muscle in GI and urinary tracts

Ataxia

Disruption of muscle coordination due to cerebellum impairment Trauma to cerebellum Alcohol inhibits cerebellum

Inferior Mesenteric Plexus

Distal colon, rectum

Glaucoma

Drainage of aqueous humor is blocked Fluid backs up, puts pressure on the retina & optic nerve Results in blindness Late signs: halos around lights, blurred vision Test: measure corneal deformation after administering puff of air

Name the 3 Cranial Meninges

Dura Mater (and extensions) Arachnoid Mater Pia Mater

Meninges Layers

Dura Mater- "tough mother", most superficial Arachnoid Mater- Middle Meninx, "spider web" arrangement of fibers Pia Mater- "delicate mother", deepest, adheres to the surface of spinal cord or brain

Cephalization

Elaboration of the rostral/anterior portion of the CNS Increase in the neuron number in the head

How are Brain Waves measured?

Electroencephalogram

Muscle Spindles

Encapsulated Nerve Ending Muscle stretch, stretch reflex initiation Perimysium of skeletal muscles

Joint Kinesthetic Receptors

Encapsulated Nerve Ending Proprioceptors, monitor stretch in articular capsules of synovial joints Includes: lamellar corpuscles, bulbous corpuscles, free nerve endings, tendon organs Provide information on joint position and motion

Tendon Organs

Encapsulated Nerve Ending Proprioceptors, stretch by muscle contraction, reflex initiation Tendons

Constriction of pupils

Enhances accommodation, prevents the most divergent light rays from entering eye

Light bends 3 times

Entering cornea Entering lens Leaving lens Lens is elastic and its light-bending power can change for better focusing

Epilepsy

Epileptic seizures caused by many electrical discharges by groups of brain neurons Causes loss of consciousness, uncontrollable jerking From genetics, head injury, stroke, infections, tumors Aura- sensory hallucination just before seizure begins Treatment-anticonvulsive drugs, implanted vagus nerve stimulator or deep brain stimulator (impulses stabilize brain activity)

Flocculonodular Lobe of the Cerebellum

Equilibrium and balance

Cholinergic Receptors: Muscarinic Receptors

Excitatory in parasympathetic target organs Inhibitory in cardiac muscles So named because muscarine mimics actions of ACh

External Anatomy of the Spinal Cord

Extends from medulla oblongata (brainstem) to superior border of L2

Diencepalon (definition and what it consists of)

Extends from the brain stem to cerebellum, surrounds the third ventricle Thalamus Hypothalamus Epithalamus (Pineal Gland)

Filium Terminale

Extension of pia mater, anchors spinal cord to coccyx

Classification by Location

Exteroceptors Interoceptors Propriceptors

Syncope

Fainting Loss of consciousness due to inadequate cerebral blood flow due to low blood pressure Example: Hemorrage or sudden emotional stress

Hyperopia

Farsightedness Distant objects seen clearly Image is focused behind the retina Correction-use of convex lens

Encapsulated Nerve Endings

Fiber terminals enclosed in a connective tissue capsule Most are mechanoreceptors Tactile corpusles- discriminative touch, dermal papillae Lamellar Corpusles- On/off deep pressure, deep dermis/subQ Bulbous Corpuscels (Ruffini Endings)- continuous deep pressure, dermis/subQ/ joint capsules

Sympathetic Responses

Fight or flight response 4 F's: fight, flight, fear, & sex Dominate during physical or emotional stress Favors body functions that can support vigorous physical activity and rapid production of ATP Dilation of pupils Increased heart rate, force of contraction and blood pressure Bronchodilation Glucose released by liver Vasodilation- skeletal and cardiac muscles, liver, adipose tissue Vasoconstiction-kidneys and GI tract

Prosencephalon

Forebrain

Choroid Plexuses

Formation of CSF in the Ventricles Networks of capillaries in the walls of the ventricles These capillaries are covered in ependymal cells Ion content is carefully monitored

Cervical Plexus Phrenic Nerve

Formed by the anterior rami of C1-C5 Phrenic Nerve: Serves diaphragm, irritation=hiccups

Brachial Plexus

Formed by the anterior rami of C5-C8 & T1 Supplies the shoulders and upper limbs

Lumbar Plexus

Formed by the anterior rami of L1-L4 Supplies the anterolateral abdominal wall, external genitals, and part of the lower limbs

Sacral Plexus

Formed by the anterior rami of L4-L5 and S1-S4 Supplies the buttocks, perineum, and lower limbs Gives rise to the largest nerve in the body- the Sciatic nerve

Coccygeal Plexus

Formed by the anterior rami of S4-S5 and the coccygeal nerves Supplies a small area of skin in the coccygeal region

What are the five lobes of the Cerebrum?

Frontal, Parietal, Temporal, Occipital, Insula

Classification by Receptor Structure

General Senses-nonencapsulated and encapsulated Special Senses

Gray Matter looks like letter "H"

Gray Commissure forms cross bar of "H" Central canal-filled with CSF Gray Matter subdivided into horns 0f anterior (ventral), posterior (dorsal), and lateral gray horns

Posterior Median Sulcus

Gray Matter Furrow on posterior side

Anterior Median Fissure

Gray Matter Groove on the Anterior side

Cerebral Cortex

Gray matter Gyri- hills Sulci- valleys

Equilibrium Pathway

Hair cells of utricle, saccule, and semicircular ducts-vestibular branc of the vestibulocochlear nerve--brain stem--cerebellum and thalamus--cerebral cortex

White Matter Tracts

Highways for propagating nerve impulses Sensory input travels towards the brain Motor input travels from the brain Name of the tract often indicates its location

Rhombencephalon

Hindbrain

Olfactory Nerve

I Sensory Nerve Sense of Smell Olfactory cells converge to become olfactory nerve

Optic Nerve

II Sensory Nerve Ganglion cells in the retina of each eye join to form an optic nerve Nerve of vision

Oculomotor Nerve

III Motor Nerve Originates in the Midbrain Supply extrinsic eye muscles to control movements of the eyeball and upper eyelid

Trochlear Nerve

IV Motor Nerve Originates in the Midbrain Controls movement of the eyeball "Pulley"

Glossopharyngeal Nerve

IX Mixed Nerve Sensory axons carry signals from the taste buds of the posterior one-third of the tongue Motor neurons arise from the medulla and deal with the swallowing and the release of saliva

Somatic Nervous System

In Somatic NS, 1 somatic neuron extends all the way to the muscle fiber, ACh is released, excitatory effect

Anterior segment

In front of the lens Anterior chamber- between cornea & iris Posterior chamber- between iris & lens Filled with aqueous humor- forms and drains continuously, similar in composition to blood plasma, nutrient/waste exchange for lens, cornea part of retina

Ulnar Nerve Palsy

Inability to abduct of adduct fingers

Wrist Drop

Inability to extend the wrist and fingers Due to injury to the radial nerve

Special Senses

Include smell, taste, vision, hearing, and equilibrium Concentrated in specific locations in the head Anatomically distinct structures Complex neural pathways

General senses

Include somatic sensation (tactile, thermal, pain, and proprioceptive) and visceral sensations Scattered throughout the body Simple structures

Long Term Potentiation

Increase in synaptic strength for memory formation Neuronal RNA content is altered, newly synthesized mRNSs delivered to axons and dendrites Dendritic spines change shape Unique extracellular proteins are deposited at synapses involved in long-term memory Number and size of presynaptic terminals may increase Presynaptic neurons release more NT

Accommodation

Increase in the curvature of the lens for near vision Change in lens shape

B1 Receptor

Increases heart rate and force of contraction; stimulates renin release from kidneys

Trigeminal Neuralgia

Inflammation of CN V Most excruciating pain known Stabbing pain for few seconds-minute, but occurs 100x/day Provoked by sensory stimulus (teeth brushing, passing breeze) Treatment: Analgesics, surgery, nerve destruction

Color blindness

Inherited inability to distinguish between certain colors Result from the absence of one of the three types of cones Most common type: Red-green color blindness

A2

Inhibits NE release, inhibits insulin secretion by pancreas, promotes blood clotting

Retina

Inner layer Originates from brain Millions of photoreceptors transduce light energy 2 layers: Outer pigmented layer-absorbs light Inner nerual layer- vision

Information about Consciousness

Involves the simultaneous activity of large areas of the cerebral cortex Superimposed on other types of neural activity (neurons and neuronal pools involved in localized activities and cognition) Holistic/Interconnected ( information can be claimed from many different locations)

Development of brain

LOOK AT PICTURE

Meniere's syndrome

Labyrinth disorder Repeated vertigo, nausea, vomiting Disturbed balance- standing erect impossible

Lacrimal Apparatus

Lacrimal secretion: aka tears, cleans and protects eye surface, composed of: mucus, antibodies, lysozyme (destroys bacteria) Nasal cavity is continuous with lacrimal duct system- secretions can fill nasal cavities and cause congestion

Focusing -Distant Vision

Lens flattens Sympathetic input relaxes the ciliary muscle, tightening the ciliary zonule, and flattening the lens

Light and Dark Adaptation

Light Adaptation: Dark-light is faster Dark Adaption: Light- dark is slower Cones regenerate rapidly whereas rhodopsin regenerates more slowly (bleached rhodopsin needs time to regenerate & accumulate) Reflexive changes in pupils occur during adaptation (pupillary reflex-bright light in one or both eyes constricts both pupils)

Light Transduction Reactions

Light changes shape of retinal-> chain of reactions resulting in closing cation channels Light activated rhodopsin-> activates transducin (G protein) -> activates PDE (deactivates cGMP) -Dark: cGMP binds cation channels to keep them open, Na+ and Ca2+ enter and depolarize cell -Light: cGMP breaks down, hyperpolarization

Photopigments: Retinal

Light- absorbing part Made from vitamin A Absorbtion of light by a visula pigment leads to structural changes

Visual Pigments (photopigments)

Located in outer segments Change shape as they absorb light Plasma membrane folded into discs-increases surface area for trapping light

Ora serrata

Margin between retina and ciliary body

Classification by Stimulus Type

Mechanoreceptors Thermoreceptors Photoreceptors Chemoreceptors Nociceptors

Convergence of eyeballs

Medial rotation of the eyeballs

Long Term Memory Storage Retrieval

Memories are stored in bits and pieces in association areas Hippocampus pulls these all together to allow us to recall them as a single event Amygdala is responsible for emotions associated with some memories Long-term potentiation (LTP)-chemical process that enhances synapses to store memories

Memory vs. Learning

Memory- the ability to hold on to or recall a piece of information Learning- the ability to retain and apply past memories

Mesencephalon

Midbrain

Red Nucleus

Midbrain Help control voluntary movements of the limbs Embedded in reticular formation

Substantia Nigra

Midbrain Large dark area (due to melanin) Melanin is precursor to dopamine Helps control subconscious muscle activities Functionally linked to basal nuclei (axons project to putamen) Loss of neurons here is associated with Parkinson's disease

Otitis Media

Middle ear inflammation Common result of sore throat Frequent case of hearing loss in children Eardrum bulges and becomes inflamed Usually treated with antibiotics Accumulation of large amounts of fluid/pus:myringotomy (lance the eardrum) & implant a tube to drain

Absence (Petit Mal) Seizures

Mild Blank expressions for seconds until consciousness disappears Typically seen in young children

Photoreceptors

Modified neurons Outer segements-receptive regions, contain visual pigments Inner segments- connects to cell body

Calcium influx activates enzymes which....( Long term Potentiation)

Modify proteins in postsynaptic terminal and presynaptic terminal (via retrograde transmission) Genes activated to stimulate synthesis of synaptic proteins via CREB (cAMP Response-Element Binding protein)

Nonencapsulated (Free) Nerve Endings

Most of these are nonmyelinated, small diameter group C fibers Temperature Pain- Vanilloid receptor opened by heat, low pH, certain chemicals (like capsaicin); Pinch, Capsaicin, temperature outside thermoreceptor range Itch Tactile (Merkel) discs (light tough, deep epidermis) Hair follicle receptors (detect hair bending)

Tonic-Clonic (Grand Mal) Seizures

Most severe, convulsive seizure (can break bones) Loss of consciousness, bowel/bladder control Takes minutes for all the muscles to relax

What are the three types of functional areas in the Cerebrum?

Motor Sensory Association

Obturator Nerve

Muscular: Adductor magnus, longus, brevis, gracilis Cutaneous: Skin of medial thigh, hip, and knee joints

Femoral Nerve

Muscular: Anterior muscles of the thigh Cutaneous: Skin of anterior and medial thigh

Musculocutaneous Nerve

Muscular: Biceps brachii, brachialis, coracobrachialis Cutaneous: Skin on lateral forearm

Medial Nerve

Muscular: Flexor group of anterior forearm, intrinsic muscles of lateral palm, digital branches Cutaneous: skin of lateral hand on ventral side Involved in Pincer grasp Compressed in carpal tunnel syndrome

Ulnar Nerve

Muscular: Flexor muscles of anterior forearm. intrinsic muscles of hand Cutaneous: Skin of medial hand Hitting your "funny bone" where this nerve rests against the medial epicondyle

Radial Nerve

Muscular: Posterior muscles of arm and forearm Cutaneous: Skin of posterolateral surface of limb

Axillary Nerve

Muscular: deltoid, teres minor Cutaneous: Skin of shoulder

Cerebral White Matter

Myelinated axons deep to cortical gray matter Communicate between cerebral areas and between cerebral cortex and lower CNS centers Classified according to the direction the fibers run

Myopia

Nearsightedness Close objects seen clearly Image is focused in front of the retina Correction-uses of concave lens

Nerve Plexuses

Nerve networks formed by ventral rami Each branch of the plexus contains fibers from several spinal nerves (due to crossing of fibers) Fibers from each ventral ramus travel to the body periphery by several routes Each muscle in a limb receives nerve supply from more than one spinal nerve

Where is the brain and spinal cord formed?

Neural Tube

Interruption in oxygen for 1-2 minutes results in? Interruption in oxygen for 4+ minutes

Neuronal function impaired Permanent injury

Anencephaly

No brain formation

NREM Sleep

Non Rapid Eye Movement Sleep Stage 1- Transition between wakefulness and sleep, lasts 1-7 minutes Stage 2- Light sleep, dream fragments Stage 3-Moderately deep sleep, night terrors Stage 4- Deep sleep, sleepwalking, night terrors A person goes from stage 1-4 in less than an hour

Right Hemisphere

Nonverbal, visuo-spatial Intuitive Creative Receives somatic sensory signals and controls muscles on the left side of the body Musical and artistic awareness Space and pattern perception Recognition of faces and emotion content of facial expressions Generating mental images to compare spatial relationships Identifying and discriminating among odors

Visceral Pain

Noxious stimulation of receptors in thoracic/abdominal cavity Vague, dull ache Travels along the same routes as somatic pain

Median Nerve Palsy

Numbness, tingling and pain in the palm and fingers

Night blindness

Nyctalopia Vitamin A deficiency

Cranial Nerve Mnemonics

O O O To Taste A Fruity Vodka Go Visit A Hotel Some Say Marry Money But My Brother Says Big Booty Matters More

Detached Retina

Occurs to trauma, eye disorder, or age Detachment occurs between neural portion of retina and pigment epithelium, fluid accumulates, retina is pushed outward Surgery can correct it, but must be done quickly to avoid permanent damage to photoreceptors

Are Rami communicantes associated with sympathetic or parasympathetic divison?

Only sympathetic They never carry parasympathetic fibers

Fibrous layer of eye

Outermost layer Sclera- "white" of the eye Covers entire eyeball except cornea

Macula lutea

Oval "yellow spot" in exact posterior Lateral to optic disc Fovea centralis- tiny pit in the center, contains only cones, images are focused when placed directly on your fovea

Enteric Nervous System

PNS "Brain of the gut"

Referred Pain

Pain from one part of the body is perceived as coming from another part

Palsy

Paralysis, often with involuntary tremors

Focusing - Close Vision

Parasympathetic input contracts the ciliary muscle, loosening the ciliary zonule, allowing the lens to bulge

Cerebral Peduncles

Part of the Midbrain Contains pyramidal motor tract axons that conduct nerve impulses from the superior part of the brain to the inferior part of the brain and spinal cord

Nerves

Part of the PNS 31 pairs Spinal nerves have 2 connections to the cord Posterior root- sensory axons Anterior root- motor neruons

Brain Stem

Part of the brain between the spinal cord and the diencephalon Consists of: Medulla Oblongata, Pons, and Midbrain

3 types of neurons in the Retina

Photoreceptors- receive light Rods- dim light, peripheral vision, black/white Cones- bright light, high-res color Bipolar cells- transmit signal Ganglion cells-generates action potentials

Plasma and CSF

Plasma is drawn from the choroid plexuses through ependymal cells into the ventricles to produce CSF

Poliomyelitis

Poliovirus enters the body from feces contaminated water Destroys ventral horn motor neurons Paralysis develops, muscles atrophy (death from paralyzed respiratory muscles or cardiac arrest)

Crossed Extensor Reflex

Polysynaptic Reflex Contralateral Contraction of muscles that extend joints in the opposite limb in response to painful stimulus Stimulus (tack)-> nerve impulse->activation of several interneurons->muscle contraction causing flexion of the leg stepping on a tack and extension on the opposite side

The Tendon Reflex

Polysynaptic reflex Control Muscle tension by causing muscle relaxation when muscle tension is great Sensory receptors- golgi tendon organs Increased tension applied to the tendon->tendon organ stimulation->nerve impulse-> spinal cord->motor neuron causes muscle relaxation and relieves tension

Flexor (withdrawal) reflex

Polysynaptic reflex Ipsilateral Initiated by painful stimuli Stimulus (tack)-> nerve impulse->activation of the interneurons-> activation of the motor neuron->muscle contraction-> withdrawal of the leg

Primary Somatosensory Cortex

Postcentral gyrus Neurons here receive info from somatic skin sensory receptors and proprioceptors Use this information to identify the stimulated body region-spatial discrimination Contralateral Amount of sensory cortex devoted to body region is related to that region's sensitivity, not its size

Somatosensory Association Cortex

Posterior to primary somatosensory cortex Integrates sensory info to produce an UNDERSTANDING of an object being felt Someone with damage to this area would not recognize objects without looking at them Can still feel sensations- sensation without integration

Parasympathetic/ Craniosacral Division

Preganglionic Neurons Cell bodies in cranial nerves of brain stem and lateral horns of sacral area of spinal cord

Sympatheitc/ Thoracolumbar Division

Preganglionic Neurons Cell bodies in lateral horns of thoracic and lumbar area of spinal cord A sympathetic preganglionic neuron has many axon collaterals and may synapse with 20+ post ganglionic neurons- this enables sympathetic responses to affect the entire body simultaneously

Pathway from Spinal Cord to Sympathetic Trunk Ganglia

Preganglionic axons Lateral Gray Horn Anterior Root of Spinal Nerve White Ramus Sympathetic Trunk Ganglion

2 Major Neurons in the ANS

Preganglionic neuron: Cell body in CNS, axon extends to the autonomic ganglion Postganglionic Neuron: Cell body in autonomic ganglion, axon extends to the effector ACh or NE is released

Precentral Gyrus

Primary motor area

Postcentral Gyrus

Primary somatosensory area

Sound

Produced by vibrating object Pressure disturbance- alternating areas of high and low pressure Hearing occurs when the auditory area of the temporal lobe is stimulated Sound waves must be propagated through air, membranes, bones, and fluids to stimulate receptor cells in spiral organ

Antidepressants

Prolong NE activity

Blood- Brain Barrier (BBB)

Protects brain from harmful substances Consists of tight junctions that seal together endothelial cells of blood vessels- end feet of astrocytes help to form these tight junctions

Photopigments: Opsin

Protein part Cones have 3 types: blue, green, red Rods have 1 rhodopsin

CSF Chemical Protection

Provides a good enviornment for neuronal signaling

Basal Nuclei Striatum

Putamen Caudate Nucleus

Basal Nuclei Lentiform Nucleus

Putamen Globus Pallidus

REM Sleep

Rapid Eye Movement Sleep Most skeletal muscles inhibited Most dreaming During a 7-8 hour sleep period, there are 3-5 episodes of REM sleep REM sleep thought to be important for brain maturation

Cerebral Cortex:Multimodal Association Areas

Receive inputs from multiple senses and send outputs to multiple areas Allows us to give meaning to the info we receive, store it in memory, decide what action to take Place where sensations, thoughts, and emotions become conscious Ex-boyfriend

Gray Matter

Receives and integrates incoming and outgoing information "Sums" EPSPs and IPSPs

Primary Visual Cortex

Receives visual information from retina

Ishemia

Reduced blood flow

Refraction of Light Rays

Refraction is the bending of light rays The cornea and lens refract light so they converge on a focal point Image is inverted - upside down and reversed from left to right

Cholinergic Neurons

Release acetylcholine (ACh) These include: All sympathetic and parasympathetic preganglionic neurons, all parasympathetic post ganglionic neruons, sympathetic post ganglionic neurons that innervate sweat glands

Adrengergic Neurons

Release norepinephrine (NE) and epinephrine (E) Release of NE can also cause excitation or inhibition, depending on what receptor it binds Sympathetic post ganglionic neurons

Renal Plexus

Renal arteries in kidneys/ureters

Parasympathetic Responses

Rest and digest Support body functions that conserve and restore body energy during rest & recovery Increased SLUDD (salivation, lacrimation, urination, digestion, defecation) Decreased heart rate Bronchoconstriction Constriction of pupils

Alzheimer Disease

Results in dementia Memory loss, shortened attention span, disorientation, language loss Cause: Beta-amyloid plaques and neurofibrillary tangles (tau) Brain Shrinkage, loss of cholinergic neurons

Long Term Memory

Retained for a long period, perhaps for life Short term memory can be transferred to long-term

Short Term Memory

Retained for short period (ex. a phone number looked up)

Vascular layer: Choroid

Rich in blood vessels Brown pigment absorbs light, preventing it from scattering and reflecting in the eye Incomplete where the optic nerve leaves the eye

Cerebral Hemispheres

Right and Left halves

Vascular layer: Ciliary body

Ring of tissue encircling the lens Composed of smooth muscle bundles-ciliary muscles Ciliary processes secrete aqueous humor Ciliary zonule (suspensory ligament)- holds the lens in position

Tinnitis

Ringing/clicking sound in the ears Usually a symptom, not a disease

Phototransduction: Rods

Rodopsin (visual pigment) captures photon of light 1) Pigment synthesis- Phodopsin forms and accumulates in the dark 2) Pigment bleaching- breakdown of rhodopsin to retinal and opsin, where rhodopsin absorbs light, retinal changes shape 3) Pigment regeneration- retinal heads "home" to photoreceptor outer segments, Rhodopsin regenerated as retinal rejoined to opsin

Roots vs. Rami

Roots: Lie medial to spinal nerves, form spinal nerves, strictly sensory OR motor Rami: Lateral and distal to spinal nerves, carry sensory AND motor fibers

Sense of Equilibrium

Rotational Equilibrium Pathway -Three semicircular canals arranged so that one is in each plane of motion -Each semicircular canal has an enlarged base called a crista ampullaris (aka crista or ampulla)--each crista contains hair cells with stereocilia embedded in a cupula -As fluid within a canal flows and bens a cupula, the stereocilia are bent and this changes the pattern of impulses carried in the vestibular nerve to cerebellum and cerebrum --brain uses this information to make postural corrections

Steps in memory

See picture ppt 12 slide 99

Sensation vs. Perception

Sensation-awareness of changes in the environment Perception-interpretation of stimuli

3 Components of the PNS

Sensory Receptors Nerves & Ganglia Motor Endings

Information flow in Cerebral Cortex Multimodal Association Areas

Sensory Receptors Primary Sensory Cortex Sensory Association Cortex Multimodal Association Cortex

Maculae

Sensory Receptors-respond to linear acceleration (not rotation) Monitor position of head in space Hair cells synapse with vestibular nerve Help control posture

Somatosensory Organization: Perceptual Level

Sensory info interpreted in the cerebral cortex Spatial discrimination- ID site or pattern of stimulation, two point discrimination test Feature Abstraction- Neuron/circuit tuned to one property of a stimulus in preference to others, allows us to identify more complex aspects of a sensation(velvet) Quality discrimination- differentiate submodalities of a sensation (taste) Pattern Recognition- Strings of notes=melody

Creation of New Memories

Sensory input processed in association cortices Cortical neurons send impulses to hippocampus & associated structures (medial temporal lobe) Prefrontal cortex & medial temporal lobe receive input from ACh-releasing neurons Memories retrieved when the same sets of neurons involved in forming a memory are stimulated

Otolithic Organs: Saccule and Utricle

Sensory structures for static equilibrium Detect linear acceleration and deceleration Contain hair cells and supporting cells Otolithic membrane rests on the hair cells and contain otoliths

Falx Cerebelli

Separates 2 cerebellar hemispheres

Falx Cerebri

Separates 2 cerebral hemispheres

Longitudinal Fissure

Separates cerebrum into right and left halves

Central Sulcus

Separates frontal and parietal lobes

Tentorium Cerebelli

Separates the cerebrum from the cerebellum

Shingles

Show dermatomes

Coma

Significant unresponsiveness for an extended period Not a deep sleep- oxygen use is much lower Due to: Cerebral or brain stem trauma, brain stem tumors or infections, metabolic disturbances (ex. Hypoglycemia), drug overdose, liver of kidney failure

Corpora Quadrigemina

Situated posteriorly and contains 4 "hills" Superior Colliculi-vision Inferior Colliculi- auditory, startle reflex

The Homonculus of Cerebral Cortex Sensory Areas

Size of the body part on chart reflects the amount of cerebral cortex devoted to that body part

Homonculus of Primary Motor Cortex in the Cerebral Cortex

Size of the body part on chart reflects the amount of cerebral cortex devoted to that part

Innervation of Skin: Dermatomes

Skin over the entire body is supplied by somatic sensory neurons Each spinal nerve contains sensory neurons that serve a specific segment of the body Dermatome: the area of skin supplied by one pair of sensory nerves

Delta Waves

Sleep waves

Superior Mesenteric Plexus

Small intestine, proximal colon

Somatosensory System Organization

Somatosensory- serves body wall & limbs, input from interceptors, exteroceptors, proprioceptors 1) Receptor Level- sensory receptors 2) Circuit Level- Processing in ascending pathways 3) Perceptual Level- Processing in cortical sensory areas

Sympathetic Division Pathways: Splanchnic Nerves

Some sympathetic preganglionic axons pass through the sympathetic trunk without synapsing in it- beyond the trunk, they form splanchnic nerves Splanchnic nerves to the adrenal medulla release hormones into blood: 80% epinephrine, 20% norepinephrine, adrenal medulla acts as sympathetic ganglion

Physiology of Hearing

Sound waves-auricle-external auditory canal-tympanic membrane-malleus-incus-stapes-oval window-perilymph of the scala vestibuli-vestibular membrane-endolymph in the cochlear duct-basilar membrane-hair cells against tectorial membrane-bending of hair cell stereocilia-receptor potential-nerve impulse

Rami

Spinal nerve exits foramen and divides into rami (all mixed) Dorsal, Ventral, Meningeal

Inner Ear: Cochlea

Spiral organ-hearing recepors Spiral, bony chamber, wraps around modiolus Divided into 3 scalae(chambers): Scala vestibuli-continuous with vestibule Scala media-cochlear duct Scala tympani-terminates at round window

Sciatica

Stabbing pain in the sciatic nerve When nerve is transected, leg is useless

Two types of equilibrium:

Static-maintenance of the body position relative to the force of gravity Dynamic- maintenance of body position (mainly head) in response to rotational acceleration and deceleration Receptors for equilibrium are hair cells in the vestibule (utricle, saccule) and semicircular canals and are collectively called vestibular apparatus

B3

Stimulates lipolysis by fat cells

ANS Reflexes

Stimulus 1) Receptor in viscera 2) Visceral sensory neuron 3) Integration center: May be preganglionic neuron, may be a dorsal horn interneuron, may be within walls of gastrointestinal tract 4) Motor Neruron post ganglionic, preganglionic neuron 5)Visceral Effector Response

Somatosensory Organization: Receptor Level

Stimulus must excite a receptor, APs must reach CNS Stimulus energy must match specificity of receptor Stimulus must be applied in receptive field Transduction-stimulus energy must be converted to graded potential Generator Potential-receptor region is part of a sensory neuron Receptor Potential- receptor is a separate receptor cell Graded potentials must reach threshold

Pulmonary Plexus

Supplies Bronchial Tree

Cardiac Plexus

Supplies heart

Dorsal Ramus

Supplies posterior body trunk

Ventral Ramus

Supplies ventral trunk and limbs Form plexuses

White Matter

Surrounds gray matter, subdivided into columns- anterior (ventral), posterior (dorsal), & lateral white columns

Sympathetic Division Pathways: To the Abdomen

Sympathetic Preganglionic fibers from T5-L2 travel in thoracic splanchnic nerves Serves stomach, intestines, liver, spleen, kidneys

Sympathetic Division Pathways: To the Head

Sympathetic preganglionic fibers from T1-T4 serving the head ascend to synapse with postganglionic neurons in superior cervical ganglia Provide sympathetic innvervation to visceral effectors of facial skin- sweat glands, blood vessels, arrector pili muscles, lacrimal glands, pineal gland, nasal muscosa, salivary glands, skin

Sympathetic Division Pathways: To the Thorax

Sympathetic preganglionic fibers from T1-T6 synapse with cervical trunk ganglia & emerge from the middle & inferior cervical ganglia Some axons of the postganglionic neurons leave the trunk by forming sympathetic nerves Innervate the heart, lungs, & skin

Sympathetic Divison Pathways: To the Pelvis

Sympathetic preganglionic fibers from T10-L2 descend to lumbar and sacral trunk ganglia Postganglionic fibers proceed to pelvic organs, distal half of large intestine-generally, these fibers will inhibit these organs

Parasympathetic Ganglia

Synapse site of autonomic ganglia Includes: Terminal ganglia-near/inside visceral effectors

Sympathetic Ganglia

Synapse site of autonomic ganglia Includes: Sympathetic trunk ganglia-on both sides of the vertebral column Prevertebral Ganglia- anterior to vertebral column

Conus Medullaris

Tapered end of spinal cord

Laceration

Tear of the brain, usually due to skull fracture or gunshot wound, cerebral hematoma results, edema, increaded intracranial pressure, swelling causes headaches, possible tissue death, fatal if brain herniates through foramen magnum

Transient Ischemic Attack (TIA)

Temporary, reversible ischemia Numbness, paralysis, impaired speech Lasts for 5-50 minutes

Winged Scapula

The arm cannot be abducted beyond the horizontal position

Parasympathetic Division Paths: Cranial Parasympathetic Outflow

The cranial outflow has four pairs of ganglia and are associated with the vagus nerve Vagus nerve carries 90% of the total craniosacral flow Sends branches to: Cardiac Plexuses, Pulmonary Plexuses, Esophageal Plexuses

Reflex Arcs

The pathway followed by nerve impulses that produce a reflex A reflex arc includes: sensory receptor, sensory neuron, integrating center, motor neuron, effector

Depth Perception

The two eyes must work together If only one eye used, depth perception is lost

Sympathetic NS Roles

Thermoregulation- vasoconstriction & vasodilation Renin release from kidneys- hormone that causes increased blood pressure Metabolism- adrenal medulla hormones: Increase metabolic rate, raises blood glucose, mobilizes fats, skeletal muscle contracts more strongly and quickly

Are the two hemispheres symmetrical?

They are symmetrical in nature, but not in function