Midterm 2 Study Set
Sympathetic division of the ANS
-aka thoracolumbar division of ANS because preganglionic neurons are located at T1-L2/3 -vasoconstriction of arteries, sweat glands, erector pili mm, dilate pupils, increases HR & BP - Short preganglionic axon(myelinated) -> ganglionic neuron (lateral to spinal cord - close to vertebrae) -> long postganglionic axon(unmyelinated) - design of sympathetic division allows for one signal to trigger a activation of regions far from initial pre-ganglionic neuron - E system: Exercise, emergency, excitement, embarrassment, ejaculation
Hasan Ibn al-Haytham
"Father of Modern Optics"; discovered refractions inversely oriented on the retina,
Short-Term Memory
(When something catches your attention) 7-8 chunks of information activated memory that holds a few items briefly, such as the seven digits of a phone number while dialing, before the information is stored or forgotten
Dorsal(posterior) root ganglion
(afferent) a nodule on a dorsal root that contains cell bodies of afferent spinal nerve neurons - grey matter
Nicotinic receptors
(cholinergic) Always excitatory (skeletal muscle and all ANS ganglia)
muscarine receptors
(cholinergic) Constantly release AcH to muscarinic receptors of heart, may be inhibitory(heart) or excitatory(gut)
ventral(anterior( root ganglion
(efferent) contain motor neurons for somatic NS - grey matter
long-term memory
(encoding) Excitement - RAS is involved (thrilling), rehearsal - repetition, Association - context(like the videos he plays for us in class to draw associations with concepts) Hippocampus interacts with prefrontal cortex in consciously retrieving memories
Diencephalon
(the deeper gray) thalamus, hypothalamus, epithalamus
cholinergic vs. adrenergic receptors
- Cholinergic receptors are parasympathetic - adrenergic (NE/E) sympathetic
Autonomic Nervous System(para and sympathetic)
- Efferent Motor system where effectors are cardiac muscle, smooth muscle, and gland - Somatic(voluntary) Autonomic(visceral: involuntary) - Lateral horn exiting through ventral root(motor) -> entering autonomic ganglion - Hypothalamus largely utilizes ANS to maintain homeostatic control (integrates cortex & limbic system information to the brainstem and SC)
CSF vs Blood Plasma
- More Na+ and Cl- - less CHO, K+ and Ca++ - Does not contain cells or proteins; if not clear, selectively permeable membrane took damage
Transduction in the auditory system
- initially takes place in tympanic membrane of middle ear (acoustic waves -> vibrations) -
Primary Motor Cortex
- the section of the frontal lobe responsible for voluntary movement with action potentials, pre-central sulcus - Motor homunculus - pyramidal cells -> corticospinal tract(output tract)
Gustation transmission pathway
1st order -> extend through facial and glossopharyngeal nerve to medulla oblongata 2nd order -> synapse in brainstem to thalamus(relay center) 3rd order -> tertiary neurons extend from thalamus to insula(gustatory cortex)
dynamic equilibrium
3 axis - turning head around pivot point Semicircular canals and ampullary cupula
Spinal Nerves
31 pairs of nerves arising from the spinal cord 8 cervical 12 thoracic 5 lumbar - conus medullaris (end of spinal cord between L1 and L2) 5 sacral 1 coccygeal
Cerebellum
A large structure of the hindbrain that controls fine motor skills. Primitive motor center: posture, balance, coordination, fine motor control, perfecting center - works with proprioceptors, visual and equilibrium pathways (joints/muscles) informs the cerebellum with static and dynamic movement - Cerebellar Ataxia traumatic brain injury - poor muscular control - match and mismatch, informs frontal lobe how to adjust, sending downstream information right away
temporal lobe
A region of the cerebral cortex responsible for hearing and language. acoustic cortex; separated by lateral fissure
Frontal Lobe
A region of the cerebral cortex that has specialized areas for movement, abstract thinking, planning, memory, and judgement
Parasympathic division of the ANS
AKA Craniosacral Plexus: - preganglionic neurons located in brainstem nuclei and S2-S4 segments of spinal cord (SPLANCHNIC): Rest and digest - S2-S4 think "Digest" - CN III, VII, IX, X (7, 9, and 10) all taste related nerves) - SLUD SYSTEM: S- salivation, L - lacrimation, U- urination, d - digestion(defecation) - Longer preganglionic axon(myelinated) -> autonomic ganglion (close to or within effector) -> short postganglionic axon(unmyelinated) - one exception for the parasympathetic system is the oculomotor nerve where the pre-ganglionic neuron is far from the post-ganglionic neuron
Olfactory Transduction
Activated Olfactory receptors initiation a g-protein second messenger system; produces cAMP -> net influx of Na+ and Ca++ -> depolarizes the cell and sends signal to glomeruli(ball of nerves that synapses between mitral and presynaptic olfactory receptors) -> mitral cell(function as relay system) -> uncus (olfactory cortex found in temporal lobe) & limbic system Convergence circuit - takes multiple inputs creating one output
Cranial Nerves and Spinal Nerves are PNS
All cranial nerves are a part of the PNS except CN II(olfactory nerve), bulb functions as it's own relay station, all spinal nerves
Preganglionic axon
All preganglionic axons release ACh onto nicotinic receptors -> post ganglionic axon releases either ACh or norepinephrine -> effector (either muscarinic receptor)
Substantia Nigra
An area of the midbrain that is involved in motor control and contains a large concentration of dopamine-producing neurons Generally a lack of substantia nigra in parkinson's patients
Visual cortex (occipital lobe)
Area of the brain responsible for the initial conscious registration of visual information; the designation of electric (nerve) impulses from the retina
Medulla
Autonomic motor reflex center; vitals center - cardiac, vasomotor, and respiratory; etc functions: vomiting, hicupping, swallowing, coughing, sneezing, and pyramidal decussation(motor tract crossing)
tonotopy
Basilar membrane and cortex are inversely mapped to Hz
sympathetic vs parasympathetic innvervation
Blood vessels: purely sympathetic (no parasympathetic innervation - can dilate and constrict blood vessels with norepinephrine Pupil: sympathetic (dilator pupillae -> more light) and parasympathetic innervation (para = sphincter Pupillae - less light) Lens: Parasympathetic causes near focus (more convex - contracted ciliary) ; sympathetic innervation - none Male genitelia: sympathetic - ejaculation; parasympathetic - erection(need to be relaxed to be aroused) Sweat glands and arrector pili: sympathetic - increases sweat and contraction; parasympathetic has no innervation Saliva: parasympathetic - increases salvation: sympathetic - decrease salvation GI tract: symp - inhibits: para - stimulates Heart: symp - increases heart rate; para - decreases HR
CNs MIDBRAIN (Mesencephalon)
CN III and IV; corpora quadrigemina - superior colliculus important for vestibulo-ocular reflex *balance - inferior colliculus gives spatial audio (sound location); substantia nigra
Cranial Nerves and which area of taste they are responsible for
CN VII -> front 2/3 of tongue, CN IX -> back 1/3 of tongue, CN X -> throat taste
Cerebral nuclei
CNS collection of glial cell (gray matter)
CNs in Pons (metencephalon)
CNs V-VIII; relay impulses from cerebellum to cortex; pneumotaxic center - controls respiration and normal breathing patterns
Long-Term Potentiation (LTP)
Cellular Mechanics behind long-term mem & learning; Encoding includes protein synthesis: - NMDA/AMPA receptors(cells which upgrade new protein receptors and allow for easier potentiation on neurons) upregulated - EPSP threshold is easier to fire - Extended time of potentiation (fires longer)
Olfaction - CN 1 Olfactory Nerve
Chemoreception Only special sense where the receptive cell is the cranial nerve! Olfactory Epithelium: contains olfactory receptor cells, which have specialized cilia extension; cilia trap odor molecules as they pass -> transmitted from the receptors to the olfactory bulb in the brain Basal cells of epithelium replace receptors (NEW NEURONS) Supporting cell - metabolic and physical support; Covid targets these cells, concert doesn't run without security ---> can lead to anosmia(lack of smell)
White Matter in PNS
Collections of axons in form of roots, nerves, and rami
Traumatic SCI(spinal cord injury)
Complete damage = no function below level of injury incomplete = varied function below injury (either sensory, motor or both)
Epithalamus
Contains pineal body. Involved in olfactory senses and sleep/wake cycle; ridge of thalamus; producing melotonin
Broca's area
Controls language expression - an area of the frontal lobe, usually in the left hemisphere, that directs the muscle movements involved in speech. Can still speak but impaired EXPRESSIVE APHASIA
Sensory Homunculus
Demonstrates that the area of the cortex dedicated to the sensations of various body parts is proportional to how sensitive that part of the body is.
epineurium
Dense connective tissue that surrounds entire nerve including fascicles and blood vessels.
Corticospinal Tract (motor)
Descending from cortex to SC; decussates in brainstem , to ventral horn of SC
Receptors
Detect sensory input and send signals to the CNS, all receptors change stimulus into graded potentials Transduce stimuli
Sour H+ and Ca++
Directly enter to inhibit and open two different channels (high pH -> protons); H+ enters and K+ is inhibited -> if k+ stops Ca++ can enter
Target Cells of ANS
Either muscarinic o
limbic system
Encompasses the fornix, mammillary body, hippocampus, amygdaloid body(appropriate response), olfactory tract, olfactory bulb - Learning, emotion/fear, appetites and sex, and endocrine interaction
Pyramidal cells in cerebral cortex
Enter the corticospinal tract(output tract) - large neurons that allow conscious control of precise, skilled, skeletal muscle movements Decussation - right brain -> left body; left brain -> right body - happens in corticospinal tract
Prosencephalon (forebrain)
Forms the Telencephalon (becomes cerebrum) and Diencephalon (third ventricle)
sweet, bitter, umami
G protein coupled receptors sensitive to certain molecules -> increase intracellular Ca++(2nd messenger) -> indirectly depolarize gustatory cells Most sensitive to Quanine(bitter chemical, upregulation of receptors=sensitivty)
Thalamus
Grand relay system(gateway to the brain); memory, emotions, and motor coordination; does not regulate temperature
Cerebral Cortex
Gray matter, every neuron has one axon, 4mm thick
Gustation (taste)
Gustatory papillae - epithelium Circumvallate - division between facial nerve(7) and glossopharyngeal nerve(9) (posterior) Fungiform - contains tastebuds (anterior tongue) filiform - do not contain tastebuds Foliate - contain tastebuds (lateral)
Light Stimulus, dark current stops
Hyperpolarizes the rods as cation channels are closed, voltage gated Ca2+ channels are closed for the rod , allowing for the bipolar cell to transmit glutamate(excitatory) to the ganglion
Coup Injury
Injury directly below the point of impact
countercoup injury
Injury on opposite side of impact
Acoustic (mechanoreception)
Inner ear(labyrinth of negative space) sense mechanical vibration; hearing=cochlear; Equilibrium = vestibule & semicircular canals
Retina
Inverses the visual field through optic nerve II; Photoreceptors dendritic(receptive end) is embedded into a pigmented epithelial cell; melanin is here to minimize the bouncing of light onto dendritic ends Signal genesis and electrical signals travel out o the retina not from retina - glial cells act like fiber optic cables to focus colored light onto cones rods and cones -> bipolar neuron -> ganglion -> collections of these ganglion cells become cranial nerve II
Sensory Association
Language is lateralized to left hemisphere Wernicke's Area is here (speech comprehension) Receptive Aphasia - sensory deficit
Visual Association area
Lemons are yellow
Duration
Longer duration -> lower Hz of APs; this is due to habituation of stimuli: receptors will stop producing neurons, stimulus has to change
Parkinson's disease
Low dopamine - generally a IPSP generator Glutamate: EPSP generator Loose the inhibitory effect of dopamine, glutamate continues to excite the neuron which meant to inhibit without any competition IPSP > EPSP in corticospinal tract; you cannot inhibit the inhibitory output of a neuron Symptoms: -paucity of motion: difficulty creating appropriate movements -resting tremors; imbalance of outputs to the brain from agonist and antagonist group -shuffling gait -stooped posture with loss of balance, freezing gait
Types of Sounds and Sensation
Lower Frequency = lower pitch (slower rate of vibration) towards apex of cochlea aka helicotrema (tonotopic organization) Higher Frequency = higher pitch (faster vibration) closer to base of cochlea (tonotopic organization) Higher amplitude = louder lower amplitude = quieter (less dramatic) Volume = wave amplitude Pitch = frequency Timbre = resonance quality (harmonic content) - characteristics of different voices
Receptor Modality
Mechanoreceptors - hair, free nerve endings, touch Chemoreceptors - gustation, smell Nocioreceptors (pain) - free nerve endings Electromagnetic receptors (photoreceptors) - sense light, vision Thermoreceptors - extreme touch and temperature
Efferent
Motor output to "effectors" which respond to environmental stimuli (muscles & glands)
REM sleep
Movement inhibited everywhere except eye muscles, Heart rate is elevated, Brain EEG is similar to that of the awake state
NREM Stages 1-4
Much deeper, restful type of sleep. Stage 1-lasts 5-10 minutes, eye movement slows. Stage 2-still fairly light sleep-brain produces sleep spindles, lasts about 20 minutes. Stage 3-beginning of deep sleep. Stages 3 & 4- Deeper sleep, growth hormones reach their peak, repairs muscles and tissues, boosts immune function, builds up energy for next day.
Brachial Plexus (5 major nerves supply entire upper limb) (C5-T1)
Musculocutaneous Nerve, Ulnar Nerve, Median Nerve; work together to form the M shape
Neurulation (3rd week)
Nervous tissue forms from thickened ectoderm (neural plate) creates a crest neural groove which will develop into the neural tube in week 4 of development - neural plate becomes the neural tube; the neural tube expands into the brain vessicles
Cholinergic Receptors
Nicotinic and Muscarinic bind AcH
Fibrous CT (Eye Anatomy)
No direct blood supply; aqueous humor indirectly nourishes the fibrous tunic: Sclera attaches to the rectus and oblique muscles; Cornea: transparent transparent CT which houses the aqueous humor
Why do we sleep? (TED) (GLYMPHATIC SYSTEM)
No lymphatic vessels in brain(no waste clearance system as performed in rest of body); CSF is pumped through the brain along the outside blood vessels which only happens while sleeping
Otolithic membrane and maculae
Otolithic membrane interacts with the hair cell; creates chronic depolarization by otoliths within the membrane constantly pressing down, so that when rate of movement changes there is a sensation hence why you only sense acceleration and deceleration
Ear Anatomy
Outer: external acoustic meatus -> tympanic membrane Middle (Air filled space): tympanic membrane -> oval window (ossicles vibrate and amplify 20x) -Stapes attaches to oval window inner (fluid - perilymph; high NA+ and Low k+): fluid filled labyrinth carries vibrations to receptors located here - round membrane - allows for movement of perilymph
Sphincter Pupillae
Parasympathetic control of pupil; causes the pupil diameter to shrink when there is no longer a need to have as much light enter the eye (lateral horn - autonomic)
Lens accommadation
Parasympathetic system - attached from CN III to ciliary body; contracts ciliary body creating a convex shape to the lens allowing for focus of near by objects
NMDA-Dependent Sensitization
Prevailing theory for chronic and recurring pain
Neural tube -> brain vesicles (Neurulation)
Prosencephalon Mesencephalon Rhombencephalon
arachnoid villi (granulations)
Protrudes through the dura mater to allow CSF to drain back into the venous circulation(empties into jugular vein)
Pruning
Pruning of long term memories occurs when there is too much upregulation and no longer need receptors binding to ligands, reduction is receptors after upregulation
Cortical Blindness
Receptor(retina) is normal but damage to visual cortex has occured; due to PCA(posterior cerebral artery) stroke
Perception
Receptors detect sensory input send signal to CNS -> Circuits connect sensory receptor to the CNS for perception -> perception is the interpretation of the signals from those receptors
Phototransduction (bleaching)
Rhodopsin gets "bleached" on the dendritic end of the photoreceptors, light makes it so rhodopsin is no longer a bent hydrocarbon chain by interacting with double bond -> kicks off second messenger system -> byproduct enter pigmented layer to be recycled (vitamin A important for recycling process): trans-retinal -> cis-retinal -> opsin -> rhodopsin
Rods vs. Cones
Rods: Primarily responsible for noncolor vision, high sensitivity to light (can function in dim light), many rods converge onto one ganglion, and 20x more numerous than cones Cones: Primarily sensitive to color(think "C"ones = "C"olor), one cone synapses onto one ganglion allowing for a more clear image as opposed to rods. Red Green and Blue receptive cones (RGB)
Spinothalamic tract(sensory)
SC -> Thalamus: decussates in SC to opposite cerebral hemisphere: Tertiary neurons = internal capsule; create sensory homunculus
More Inner Ear Anatomy (transduction)
Scala Vestibuli - ascends to apex of cochlea Scala Tympani - descending portion of cochlea Cochlear Duct - between Scala vestibuli and tympani; filled with endolymph and contains the organ of corti Organ of Corti - Filled with hair cells(stereocilia); closely covered by tectorial membrane(doesn't move) -> basilar membrane moves and pushes hair cells up and bending -> mechanically opening potassium mechanically gated channels and allowing for depolarization of the cell
General Sensation
Somatic(touch, pain, pressure, and temperature) and Visceral(pressure and pain
primary sensory cortex
Somatosensory cortex, feelings of touch, pain, proprioception(idea of where you are in space), temperature would be experienced by "you" here
Special Sensation
Specific stimuli: vision, hearing, taste, smell, equilibrium
Sensation
Stimulus -> receptor -> nerve transmit info (afferent) -> brain interprets(conscious awareness) -> conscious awareness of a stimulus
Intensity
Stronger Stimulus -> higher Hz of APs Certain number of APs based on intensity, the brain communicates in frequency (Hz)
cerebral spinal fluid(CSF)
Sub-arachnoid space between meninges is filled with this fluid that cushions and protects the CNS Space of Neural tube -> turns into ventricles -> filled with CSF Function: Buoyancy(suspend brain & spinal cord in fluid), Protection(ECF stability - waste removal, hydraulic shock absorber, stable environemnt)
2nd order(Perception)
Synapses with 1st order in CNS; decussation in SC or medulla and ascends to the synaptic cleft of the thalamus
1st order(perception)
The afferent signal on the PNS nerve
Photopsin
The visual pigment for cones, the populations isoforms are based on light nm, RGB, heavily concentrated in fovea centralis
Primary Acoustic Cortex
Tonotopic mapping - senses which Hz(frequency) of sound is being heard
White Matter
Tracts(internal Capsule) - Brain and Spinal Cord to communicate with each other Commissures (in corpus callosum) - connect gray matter of the two hemispheres; Association Tract - communication between left and right hemispheres
Beta Receptors
Usually inhibitory (With exceptions: pacemaking cells of your heart - bind norepinephrine to speed up heart rate) Beta-blocking medication take a drug with a higher affinity than norepinephrine to prevent varied conditions (heart failure/chest pain/heart attacks)
Auditory Pathway
Vestibulocochlear nerve -> medulla -> midbrain -> thalamus -> primary auditory cortex(temp. lobe)
Fascicle
a bundle of nerve or muscle fibers bound together by connective tissue
Benign Paroxysmal Positional Vertigo (BPPV)
a common cause of vertigo that occurs when there is a shift in the location of small crystals in the semicircular canals Epley Maneuver: move displaced otoconia from maculae back into the semicircular canal, otoliths which take a joy ride in the semicircular canal would bump into the cupula
dermatome map
a diagram of the cutaneous regions innervated by each spinal nerve
Blood-Brain Barrier (BBB)
a selective mechanism that protects the brain from toxins and infections; Junction of astrocytes Function: - defends osmolality - Waste products - Pathogens - Toxic Substances like drugs - Wilf fluctuationsterm-148 What crosses: CHO, Amino acids, some ions via transport channels. LIPID SOLUBLE PRODUCTS CAN CROSS: FFA , O2, CO2, EtOH
Hydrocephalus
abnormal accumulation of fluid (CSF) in the brain Cause: abnormal CSF flow and resorption Signs: rapid head circumference increase, "Sun-setting" downward gaze of the eye, Vomiting, irritability, seizures Case study Qs: Enlarged lateral ventricles - lack of septum pellucidum, CSF not flowing out lateral ventricles, sutures are inflexible in adults
Alpha Receptors
adrenergic receptors that are usually stimulatory
"General Sense"
any sensory system that is distributed throughout the body and incorporated into organs of multiple other systems, such as the walls of the digestive organs or the skin; carried out by dorsal root ganglion - signals when threshold is met through spinothalamic tract - decussation applies here too
fovea centralis
area consisting of a small depression in the retina containing cones(no rods) and where vision is most acute
gustatory cortex
area of the brain that receives and interprets tastes from the tongue; part of insula which is a section of the parietal and temporal lobe - Think emotional eater; think limbic system
Reticular Activating System (RAS)
brain area that plays a key role in arousal; Spinothalamic interaction which carries out through the cortex; brain stem integrates, serotonin & norepinephrine released resulting in -elevated heart rate, breathing rate, and kidney activation
motor homunculus
broad areas of primary motor cortex devoted to controlling movements of different body reterm-37gions
Vestibule mechanoreceptions
causes influx of Ca++ triggering depolarization of hair cells Transduction occurs in vestibule and semicircular canals
Gray Matter
cerebral cortex Cerebral nuclei
vascular tunic
choroid, ciliary body, iris(2 diff muscles)
Perineurium
coarse connective tissue that bundles fibers into fascicles
Myopia (nearsightedness)
condition in which close objects appear clearly, but far ones do not; concave lens of glasses would help treat
Intraventricular foramen
connects lateral ventricles to third ventricle
Cerebral aqueduct
connects the third and fourth ventricles
Superficial cerebrum
cortex (grey matter), lobes are distinguished with the central sulcus, parietal occipital sulcus and the longitudinal fissure
Endoneurium
delicate connective tissue around individual nerve fibers in nerve
Dura Mater
dense irregular connective tissue (Durable matter)
Ectoderm
develops into nerve tissue and skin; forms an exoskeleton
neural plate
flat group of cells present in prenatal development that becomes the brain and spinal cord
Ventral Rami
form a complex of networks (plexus) for the anterior (MOTOR & SENSORY); bigger than dorsal because it goes everywhere
Gray matter in the PNS
ganglia (collections of neuron cell bodies in PNS)
ampullary cupula
gelatinous material that hair cell cilia are embedded in; lag in movement of endolymph and cupula
Dural venus sinus
group of sinuses or blood channels that drains venous blood circulating from the cranial cavity (basically an arachnoid granulation)
Receptive field
important for discrimination, the greater the receptive field of one dendrite/neuron the less proficient it is at distinguishing stimuli
Afferent
input entering CNS and delivered by the PNS, afferent can also be CNS to CNS
somatosensory association area
integration and interpretation of somatic sensations; comparison of past to present sensations; Afferent area of your brain, any homeostatic mechanism comes here, processes sense of touch, pain, proprioception; things like "did i like that touch"
Basal Nuclei
internal islands of gray matter in CNS
Taste physiology of salt (Na+ and K+) transduction
metal ions dissolve in saliva -> cation enters taste pore -> directly enters cell
Rhombencephalon (hindbrain)
metencephalon -> pons & cerebellum and myelencephalon -> medulla oblongata
Mesoderm
middle germ layer; develops into muscles, and much of the circulatory, reproductive, and excretory systems
Static equilibrium
moving side to side and up & down: vestibule Comprised of Utricle and Saccule Utricle - Horizontal acceleration Saccule - Vertical Acceleration When looking down -> reduced action potential (otoliths don't compress hair cell as much)
Myotomes
muscle or groups of muscles innervated by a specific motor nerve
Nerve Plexus
network of interweaving anterior rami of spinal nerves
Dilator Pupillae
opens the pupil under sympathetic stimulation; if you need more light it will dilate (lateral horn - autonomic)
Hypothalamus
part of diencephalon, function to: -Grand puba of homeostasis -thirst center -appetite and weight control -physical responses to emotions -blood pressure and heart rate -sleep cycles
Neural Crest
pinches off - develops sensory(dorsal root) ganglia of PNS (ENTIRE PNS)
pre-motor cortex
plans and coordinates skeletal muscle movement; association cortex - uses tracts collterm-35ections of axons (corona radiata)
Circuit Level
processing at this level is involved with delivery of impulses to the appropriate region of the cerebral cortex for stimulus localization and perception
Choroid Plexus
produces CSF; selective membrane; braiding of the choroid plexus takes up space of the ventricles Ependymal Cells - glial cells Endothelial Cells - capillaries
Parietal Lobe
receives sensory input for touch, taste and body position, post central gyrus - Primary sensory cortex Contains somatosensory association area
Multimodal Association
receiving inputs from multiple sensory modalities; integrates information and formulates composite higher experience: Imagination, judgement, decision making, long term planning
Amnesia
retrograde can't recall memories; anterograde - can't form new memories
Lacrimal Gland
secretes tears; controlled by cranial nerve 7 (VII)
Maculae
sensory receptors for static equilibrium
dark current (rods)
sodium and calcium channels open in the absence of light -> depolarizing the cell -> causes rods to constantly release glutamate(normally excitatory in CNS but inhibitory here) -> inhibits If the bipolar cell receives glutamate it hyperpolarizes the bipolar cells and inhibits
Acoustic association area
stereo and localization
3rd order(perception)
thalamic projection neuron sends signal to primary somatosensory cortex(in parietal lobe)
Dorsal Ramus
the division of posterior spinal nerves that transmit motor impulses to the posterior trunk muscles and relay sensory impulses from the skin of the back; dorsal is smaller because it relates to only the back (MOTOR & SENSORY)
sensory memory
the immediate, very brief recording of sensory information in the memory system
Endoderm
the inner germ layer that develops into the lining of the digestive and respiratory systems
Mesencephalon (midbrain)
the midbrain; a region of the brain that surrounds the cerebral aqueduct; includes the tectum and the tegmentum
Primary Visual Cortex
the region of the posterior occipital lobe whose primary input is from the visual system
gate-control theory
the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain Interneurons generally inhibitory ; gate=nociceptor inhibits the interneuron, so pain continues to the cortex
nervous tunic (retina)
the starting point of the visual pathway containing photoreceptors(not neurons)
Transducing stimuli
turn into graded potentials and release neurotransmitters onto neurons -> conduct APs Code for type of stimuli, location, intensity and duration
Olfactory cortex
up to 2nd order nerves
orbital cortex
use of rewards to guide behavior; inhibits undesirable behavior
uncus
ventral surface of temporal lobe; part of limbic system; used for smell part of olfactory cortex
shingles (herpes zoster)
viral infection producing the eruption of highly painful vesicles that may follow a nerve path; causes pain in dermatome affected
Referred pain
visceral pain may feel as if it is coming from some part of the body other than the part being stimulated (soma pain) i.e: heart attack