Immunology

Immunology

Immunology Quiz!What are the three lines of host defenses?

Covering of the body (skin, mucous membrane)InnateAdaptive (acquired)

Skin and mucous membranes Physical barrierEpidermis, cilia movement, low of air/fluidChemicalpH, enzymes, other antibacterial peptidesMicrobiological: Normal flora Quiz!What are the organs of the immune system?

Primary bone marrowthymus glandfetal liver and yolk sacSecondary lymph nodesSpleenmucosa-associated lymphoid tissue

InnateNO MEMORYCellular Phagocytic cells Cells with inflammatory mediators HumoralAcute phase reactantCytokinins Example of phagocytic cells: neutrophils, macrophage, dendritic cells)Cells with inflammatory mediators such as basophils, mast cells, eosinophils Acute phase reactant: c-creative factor Cytokinins: interferon alpha5Order of recruitment Macrophage Innate immune system Found in all organs/tissuesEspecially where epithelia are in contact with exteriorPseudopods attracted to bacteria Derived from monocytesMajor function: engulf particlesSend signals for neutrophil via cytokines (Interferon alpha)Order of recruitment Neutrophils InnatePolymorphonuclear cell family PMNs (with basophils and eosinophils)Found in blood stream Come in massive number Eats the bacteriaThen dies

Order of recruitment After macrophage does its job, it returns to regional lymph nodes and calls for Dendritic cellsBorderline between innate and adaptive Eats virtually everythingTakes in bacteria, carries pieces of it on its surface Gets back to lymph node

The fight is localized to the lymph nodes now 8How does phagocytic cells recognizes bacteria from self?Toll-like receptors PRR pattern recognition receptorsRecognized PAMP pathogen-associated molecular patternsType I trans-membrane receptor N-terminal: outside the cell, recognize ligandsC-terminal: inside the cellActivate inflammation and kick starts immunity

9QuizWhat are Lipopolysacchides (LPS)?They are PAMPGram-negative bacteria

Peptidoglycan (PGN) are Gram-positive bacteria Adaptive Antigen (and epitope) specific

Antigen presenting cells (APC) (MHC+peptide)Interdigitating dendritic cellMacrophageB lymphocyte (B cell)Adaptive I. Humoral ImmunityRESPOND TO Extracellular pathogens (e.g., bacteria)Antigen presenting cells (APC) MHC II+peptidePARTICIPANTS TH2 (CD4+)-helper lymphocyteB lymphocyteT cell-B cell interaction (cooperation)Immunoglobulin antibody productionAdaptive II. Cell-mediated ImmunityAntigen presenting cells (APC) MHC+peptideRESPOND TO Intracellular pathogens (e.g., viruses)PARTICIPANTSTH1(CD4+)-helper lymphocyteTc (CD8+)-cytotoxic lymphocyteT cell-Tcell interaction (cooperation)Effector cell is the CD8+ cytotoxic lymphocyteQuizWho is Paul Ehrlich and what was his theory?

Side-chain theory cell under threat grew additional side-chains to bind the toxin, and that these additional side chains broke off to become the antibodies that are circulated through the body

The other guy is linus pauling direct template theory specificity of Ig is not determined by AA sequence but by process of moulding around an antigen WRONG14Major Histocompatibility ComplexTwo molecular system MHC I present in almost all nucleated cellMHC II Present in APC (macrophage, dendritic, B-cell)In each class, molecules have two chains- alpha and beta QuizHow many alpha chain does MHC I has?

MHC I large alpha, small beta-2MHC II alpha and beta are the same size

What class of MHC is on dendritic cell?

16

17Lymphocytes All starts in the bone marrow stem lymphocytes Some will go to Thymus T-cellsSpecialized in that microenvironmentBecomes either CD4 or CD8Some will remain in the Bone marrowB-cellsMigration to lymph nodes

Maturation TCR (T-cell surface receptors) and slg (B-cells Specific Ig) are formed randomlyEarly T-cells are double positive (both CD4 and CD8)CD4 TH1, and TH2, recognizes MHC IICD8 Cytotoxic T-cells, recognizes MHC I95% of all T-cells are deleted in the thymus If they dont recognize MHC or recognize it too well

QUIZ(T/F) Deletion of T-cells (selection for reactivity to MHC-peptide tolerance) stops at the age of 6 month

False, it is a life long phenomenon QuizzzzzCD 8 becomes what cell?Cytotoxic T-cellCD 4 becomes helper T-cell: target for HIV QuizzzT cells are found in the superficial cortex of the lymph nodes

Then you have dendritic cells that moves in between B and T cells

Interacts with both FALSE!!22Continuing the sequence1st specific reactionBinding of MHCII (dendritic cell) to T-cellGenetically programmed to recognizes one epitope

Very specific now 23QuizWhat make sure that T-cell are not attacking self?

On dentritic cell: B7CD-80, CD-86On the T-cell: CD 28Confirms that it is not attacking self Intracellular: costimulating factor giving the signal to attack

B-cell recruited: ligande CD40L (T-cell) with CD40 (B-cell) B-cell receptor surface immunoglobuline recognizes the surface of the bacteria

Quiz!!!What does IL 4, 5, 6 do? Interleukins that causes the maturation and proliferation of B-cell Produces more antibody

Quiz!!(T/F) B-cell becomes a plasma cell and start to make antibodiesFalse!!!

B-cells proliferate (under influence of interleukins) and makes antibodyWhen it becomes a plasma cell, it no longer makes antibody, only secrets it Antibodies Humoral immunityIg

Structure4 chains2 identical light chains 2 identical heavy chains

Quiz(T/F) Both intra and inter chains are held together by disulfide bound Five (5) Classes determined by the Heavy (H) Two (2) Types determined by the Light (L) kappa, lambdaFab = antigen binding fragment hypervariable regionFc = crystalizable fragment Taildetermines the biological actvity of the Ig Class

Classes of Ig IgM class muFirst activated Recognizes A or B antigen on RBCIgG class gamma Only one that can pass through placenta Bacteria, virus, fungi, etc. IgA class alphaMucosal immunityFound in saliva, tear, other secretion IgE class epsilon Allergies

IgG: the one that protects the fetus in utero 31QUIZWhich Ig is monomeric?

Remember that meric refers to how many unit Valent refers to how many sites it has meric *232After antibody binds Antibody cant do anything until it borrows complements from the innate system

MBL: acute phase protein recognized carbohydrate patterns on pathogensAlternative: we will come back to it34

What to remember?Its a cascade, each amplifies the waterfallC3 and C5 calls for neutrophil phagocytosis Later molecules in the sequence C9 punches a hole in the bacterial membrane

Alternative pathway: more primitive, activated by PAMP (macrophages)37

In genome, 200 genes code for immunoglobulins DNA from these genes cut, then rearranged and rejoined Accounts for millions of possibilities The last one C determines the class (IgM, IgG, IgE, IgA)

Quiz(T/F) B-cell can change the class of Ig it produces True: Class switch can occur in the apical light zone

IgM often switches class

Memory With each cycle, the number of surviving memory cells increases. Increase is accompanied by affinity maturation survival of B cells that bind to the particular antigen with high affinity secondary immune responseAfter exposure, B cells differentiate into plasma cells that secrete antibodies A small minority survives as memory cells that can recognize the same epitope

Quiz(T/F) B-cells need T-cell to activate and produce antigens. False!B-cell can produce and secrete antigen without T-cellT-cell causes B-cell to proliferate and render them much more efficient Killer T-cell: response to virus

Infected cell dies, dendritic cell cleans up the messRecognizes bits and pieces of virus Present it to T-cellT-cell calls on Tc via INF IL2Tc binds to infected cell via MCH IKills the cell 43CNS Sensory/Cognitive/MotorMajor DivisionsAfferent

Cranial NervesSpinal NervesTouchPain Temperature Visceral Efferent

Cranial NervesSpinal NervesSomatic (voluntary)Involuntary Enteric

Afferent: cell outside of CNSEfferent: cell inside of CNSKnow your anatomy

45Quiz!What structure connects the two hemispheres?

Corpus Callosum QuizT/FThe dorsal root carries motor neurons False!Ventral root carries motor neurons QuizBy which week of gestation do the neural plate start to form?3rd!Neural tube Ectoderm starts to fold and forms the neural grooveNeural groove eventually becomes neural tube (4 weeks)Neural tube becomes CNS

Bits and pieces of ectoderm forms neural crestNeural crest forms PNS

Cerebrospinal Fluid (CSF)Produced by Choroid Plexus @ rate of 500 ml/dayVentricle can only contain 150mL

Function is SNoWSupport and cushion the brainNOurishment Waste removal arachnoid villi

CSF Circulation Chroid plexusLateral ventricleForamen of Monro3rd ventricleCerebral aqueduct4th ventricleForamens of Lushka & MagendieSubarachnoid spaceDural sinusVenous blood Heart

Problem with circulation Communicating Hydrocephalus Problem with CSF removal arachnoid villi inflammation Pressure starts to build up outside the ventriclesEventually a global increase in pressureNon-communicating HydrocephalusPressure build-up inside the ventriclesNot necessarily affect all the ventriclesLocalized

Quiz!Glycogen is the only substrate metabolized by the brain False!Glucose

The brain need a continuous supply of glucose and O2Brain Blood Supply

External carotid artery Internal carotid arteryBasilar artery

Usually tight junction btw epithelial cells BBBPassH2OCo2O2Lipid soluble Na+K+Cl+Active transport of GLUCOSE and AMINO ACID Blocked Large molecules

Quiz!What are the function of astrocytes?Phagocytosis of debrisReuptake of neurotransmitters (such as Glutamate)Regulation of ion concentration i.e. reuptake of K+ Structural supportInduce tight junction (BBB)

PerceptionLaw of specific energy

MODALITY!Regardless of the type of energy that stimulate a nerve, the sensation felt correspond to nerve type Rubbing eyes Law of projection

LOCATION!Regardless of where you stimulate a sensory nerve, the sensation is always felt at the sensory receptor location Phantom limb painAdaptation of afferent Non-adaptingConstant discharge even if there is no change in stimulus You constantly feels the sensation Slowly-adapting Discharge stops slowly if there is no change in stimulus You still feel the sensation but less and lessRapidly-adaptingDischarge stops if there is no change in stimulus You stop feeling the sensation after a whilei.e. do you feel your underwear all day long?Receptive field Strongest in the middle

Smaller RF = increase acuity

Overlapping receptive fields: the one that respond the loudest determines location

Lateral inhibition further sharpens acuity

QuizT/FSignal from the brain can decrease the pain from a paper cut TrueSensation is shaped by both:Bottom up mechanical stimulation on the skinTop down CNS signalsTop down inhibition/excitation can be presynaptic or postsynaptic

Quiz!Mechanoreceptors are activated by what?By mechanical deformation!Stretch of the skin that opens channels QuizzzzzzzT/FCutaneous mecanoreceptor nerve ending are all the same, the only difference is the types of tissue surrounding them and there they are located True!End organ allows only selective mechanical information to activate nerve terminalMeissner and Merkle (M&M): superficial - light touch, texturePacinian and Ruffini: deeper - stronger deformations of the skin deep pressure, shape Other sensation!ThermoreceptorsCold: 0-35 CWarm: 30-50 C>50C PAIN!NociceptorsMechanical deformationTemperatureChemicalsQuiz!T/FInflammatory molecules increase the threshold of nociceptors, causing hyperalgesia FALSEHyperalgesia: sensitive to painIncrease threshold: more AP to actually cause painHyperalgesia is associated with decrease threshold less AP to cause pain Another one!T/FHistamin Bradykinin5-HTProstaglandinK+Activates nociceptorsThis leads to release of substance P at both spinal cord and the site of injuryThis one is TRUEActivation of nociceptors leads to release of substance P (for pain) in the spinal cord and afferent feedback onto mast cells

Mast cells then secrete histamine, further sensitize the nerve ending PathwaysTouch and ProprioceptionIpsilateralDorsal column Synapses @ medulla (x-over), thalamusPain and TemperatureContralateralAnterolateral columnSynapses @ dorsal horn of spinal cord, thatlamusCNS Analgesia PAG periaqueductal gray matterReticular formationBoth are from medullaDecends in dorsalateral funiculusPresynaptic or post synaptic inhibition

Quiz!T/FThe fovia centralis is where all optic nerves are leaving the retina, therefore it has the highest visual acuity False

Optic disk is where the optic nerve are exiting the eye

Fovia centralis is the highest visual acuity area, that is true Quiz!T/FThe cornia refracts light more than the lens TrueQuiz!T/F

If the eye is myopic, then the image is formed behind the retina

This condition can be corrected with concave lensFirst part is false myopic = nearsighted, image is formed before the retina

Second part is true myopia is corrected with concave lens

Nourishes rods and cone detached retina: separation of retinal from pigmented epitheliumBipolar / Amacrine / Horizontal cells : process, compress, converge raw data from rods and conessend info to brainRetina circuitry may prevent light from getting to rods and cones In fovea centralis, the circuitry is shifted out of the way 75Phototransduction In the dark, the cell is depolarizing, transmitter always released by the inner segment Light hits rhodopsin/opsin molecule (outer segment) change in configuration Reaction via G-protein cascade cGMP is converted to GMPCloses the cGMP gated channelNa+ can no longer flow inHyperpolarization stops release of transmitter by the inner segment

Many quizzzzesDay vision

Slow response time

Sensitive to scattered light

Low amplification

Single photon closes many Na+ channels

High acuity

Less convergent Cones

Rods

Rods

Cones

Rods

Cones

ConesCenter surround theoryRetina ganglion cells Help to detect the RELATIVE difference of light across their receptive field

The same processing can be applied to color Red, blue, green

While crossing Dr. Penfield, a car is coming FULL speed from the right will Bobby see it?Yup, R visual field of R eye will spot the car Yup, R visual field of the L eye is okayYup, R visual field of both eye would be okayYup, intact R visual field of R eye Noooooooooooooooo

Deflection of basilar membrane produces shearing of hair cell stereociliaAs they move, tip link that connect each sterocilia pulls open gated ion channel and causes depolarization Its a fast, direct channel activation

QuizT/FAuditory information is carried by the 8th cranial nerve, it synapses with a 2nd order neuron in the medulla, crosses over, and is sent to the contralateral Primary auditory cortexFalse! its bilateralBilateral pathway allows for sound localization (base on time difference of signals from each ear)Semicircular Canals

Detects angular acceleration

82Semicircular Canals

No angular acceleration

Clockwise acceleration inertia causes endolymph to lag behind - cupula deflects toward counterclock wise

Perceived sensation: clockwise

Constant clockwise motion cupula not deflected Canal stoppedMomentum keeps endolymph moving cupula moves with endolymph in the clockwise direction

Perceived sensation: counterclockwise

Semicircular CanalsUtricle and Saccule

UtricleHORIZONTAL accelerationSacculeVERTICAL acceleration

Mechanism: Otoliths lags behind and pulls on the hair cells

85Gustatory Salty: Na+ - direct effect on sodium channelSour: H-- direct effect on sodium channel, can interfere with Na+Bitter: G-protein cascadeA lot of way to transduce bitternessSweet: G-protein cascade

OlfactoryMolecules dissolved in mucus, detected by olfactory receptor cellsG-protein cascade leading to opening of ion channelSynapse at the olfactory bulbThe only sensory modality that does not have synapse at medulla or thalamusOlfactory bulb has direct connection with the limbic system strong effect on emotion and memory

Cognition Alpha rhythmRelaxed stateLow frequencyHigh amplitudeBeta rhythmAlert stateHigh frequencyLow amplitude QuizT/FAs you fall deeper asleep (stage 1-4) amplitude increases and frequency decreasesTrue!QuizCircadian rhythm is controlled by what structures of the brain (3)Preoptic area (hypothalamus)Suprachiasmatic nucleus (hypothalamus)Reticular activating system (reticular formation)State of conciousnessFactors to considerReticular activating system Aminergic neuron and Serotonin Cholinergic neuronHypothalamusGABAHistamine

Tricks to help to rememberSerotonin makes you happy and excited anything that makes serotonin go up will be associated with alertnessThe two nergic systems goes against each otherGABA always associated with decrease in activity QuizDopamine is produced Olfactory bulbMidbrainPrefrontal cortexLocus CeruleusHippocampusAmygdala Midbrain D

Dopamine reward pathway (Locus ceruleus, midbrain, prefrontal cortex)Case study 1Mrs. D has undergone an aggressive surgery to treat glioma (tumor). A large part of her hippocampus and basal ganglia are removed. What type of memory deficit do you anticipate for Mrs D? Basal ganglia long term procedural memory (i.e. how to play tennis)

Hippocampus short term declarative memory (i.e. what she had for breakfast this morning)

Case study 2Mr. W had a left middle cerebral artery stroke 2 m.o. ago. When asked how he is doing he responds

Well I eat grasshoppers and boy does that shin look chipy bog

Which area is affected? Broca or Wernicke?Wernicke: comprehension

Brocas area is more just articulation. They understand fine and can formulate sentence that makes sense

MotorExtensionFlexionAgonist Antagonist Monosynaptic stretch reflexAgonist excitation: THERE IS NO INTERNEURONS!!

Motor cheat sheatCorticospinal voluntary movementPyramidal ContralateralSynapse with ALPHA motor neuron in the VENTRAL horn (via interneuron most likely)Extrapyramidal posture, trunkExtrapyramidal Ipsilateral Alpha motor neuron: skeletal muscle (extrafusal)Gamma motor neuron: intrafusal, monitor muscle length Flexion withdrawalTouch something hotSensory fiber transmit pain Activate ipsilateral flexors (via excitatory interneuron)Inhibit ipsilateral extensors (via inhibitory interneuron)Result in removal of arm from the stove whole process does not require cortical input

Cross extensor reflexJust remember: the interneuron that crosses to the contralateral side is always excitative.

Therefore to inhibit contralateral side, you need a 2nd interneuron to do this

QuizWhat is irridation?Increase in rate and magnitude of withdrawal response with increased stimulus strength

The more it hurts, the stronger your reaction is going to be 100Muscles

Parallel system Ia (Nuclear bag fibers)Dynamic change in muscle lengthTakes into consideration the relative length of the muscle IIa (Nuclear chain fibers)Static muscle lengthOnly mind the absolute length of the muscle When a muscle is lengthened, there is no problemWhen a muscle is in shortened position, muscle spindle collapse and sensitivity is reduced Decrease in force production 102Parallel system Solution: Gamma motor neuronActivate and cause contraction of muscle spindleTension is put on the spindle and sensitivity is maintained Able to apply further force and continue contraction

ALPHA GAMMA CO-ACTIVATION

Series systemGolgi Tendon OrgansIb afferentReports muscle tension Prevent muscle injury by inhibition of the same muscle when too much stretch is put onto itUnderlies inverse stretch reflex (polysynaptic)

There is also an excitation of antagonist muscle (not on the picture)

GTO is the main underlying mechanism for stretch reflex

N.B: The stretch reflex (knee jerk) is usually considered to be the same thing as GTO reflex.

Motor ControlPremotor: planning and initiation Primary motor: encode motor command Fine tuning of motor commandBasal ganglia sequenceCerebellum amplitude modification, timing of movement Brain stem posture, balance

Time for Quiz!Spasticity results in what?It is associated with damage to motor neuron or higher level motor pathway?Spasticity: high muscle tone, overactive motor reflexesIt is a upper motor disease damage to CNSWithout any input from the brain, gamma motor neuron (reflex) takes over Basal Ganglia Parkinson diseaseREDUCED dopamineAkinesia BradykinesiaRigidity Resting tremor Huntington diseaseTOO MUCH dopamineHyperkinetic Choreiform movement

Cerebellum disordersAsynergiaDysmetriaAtaxiaIntention tremorParalysis and weakness (?)Muscle and ANSDescribe the three different types of muscle.Define the terms muscle fiber, tendon, myofibril, sarcomere, I band, A band, Z line, thick filament, thin filament, actin, myosin.Explain the sliding filament model of muscle contraction.Describe the actin-myosin cross-bridge cycle. Understand why muscle contraction requires hydrolysis of ATP.Define the terms motor neuron, motor unit, neuromuscular junction, motor end-plate, acetylcholine, nicotinic acetylcholine receptors, end plate potential.Explain synaptic transmission at the neuromuscular junctionExplain excitation-contraction coupling.Explain the difference between slow oxidative, fast oxidative and fast glycolytic muscle fibers.Understand the length-tension relationship of muscle fibers.Define the terms twitch, summation, tetanus and recruitment. Explain how summation and recruitment contribute to generation of muscle force. Explain the factors that contribute to muscle fatigue.Know the characteristics of neurogenic, myopathic and upper motor neuron disorders.Describe the three types of muscleSkeletal stripped PostureLocomotion Voluntary CardiacHeart muscleSmoothOrgansBlood vessels

Muscle fiberMade of multiple precursors called myoblastMultinucleated Stripped Muscle fiberSkeletal muscle fibers consist of cylindrical bundles called myofibrils.MyofibrilMyofibrilMyofibrilThe striations within each myofibril are caused by alternating light I-bands and dark A-bands. In the center of each light band is a dark line called the Z-line. These structures delineate the sarcomere, the contractile unit of skeletal muscle. A bandI bandZ lineSarcomereEach sarcomere consists of two sets of parallel and partially overlapping protein filaments: thick filaments extending from one end of the A band to the other, and thin filaments, attached to the Z lines and extending across the I band and part way into the A band. Z lineZ lineSarcomereThick filamentsThin filamentsCrossbridgesQuizWhat makes up the thin filament?ActinThick filament is made of Myosin Two views of actin thin filaments and myosin thick filaments in a sarcomere.The sarcomere contracts when thin filaments slide over thick filaments. The cross-bridge cycle is driven by ATP binding and hydrolosys by the myosin head groups.ATP hydrolysisADP + PiMyosin bindsto actinADP + PiPower strokeATPMyosin dissociationADP + PiMyosinQuiz!What is included in a motor unit?(2)Motor neuronGroup of muscle it innervates

Synapse are usually located at the middle of the muscle belly QuizWhat neurotransmitter is release at the neuromuscular junction?AChActivating NICOTINIC receptors AP travels down T-tubulesOpens the voltage gated Ca+ channels in the T-tubulesThis is coupled with activation of Ca+ channels in Sarcoplasmic reticulumCa+ released from SR cause muscle contraction

T-tubuleSarcoplasmic reticulummyofibrilMuscle fiber surface123QuizT/F Muscle contraction is possible even if T-tubules are blockedTrueAbility of muscle to contract is coupled with Ca release by SRT-tubules are more signal detectors, not very important for contraction of skeletal muscles Cadmium Ca+ blocker Ca+ cause conformation change in troponin moves the tropomyosin out of the wayFree the binding site for myosin head ActinTropomyosinTroponinCa2+ binding siteMuscle types Runners

Springers

Soccer playersSlow oxidativeLow ATPaseRed O2 transportEnduranceFast glycolytic High ATPaseNo myoglobinPower Combined Muscle contraction All or nothing Delay in excitation-contraction coupling Duration of contraction time it takes to pump out Ca+

Twitch 1APSummation closely packed twiches Tetanus sustained contraction, summation of very fast, successive twiches What is another way to control muscle force?Summation

Order?

Weaker units are recruited firstSlow oxidativeFast glycolytic Fast oxidativeQuizWhat are the three factors of muscle fatigue?Build-up of potassium in the t-tubules loss of chemical gradient needed for depolarization Lactic acid build-up change in pH, alteration in protein structure ADP-Pi build-up in the muscle fiber inhibition of cross-bridgeDisease of motor unit Spinal cord injury after an accident on Dr. PenfieldUpper motor neuronSpasticityOveractive reflex

Disease of motor unit Duchene Muscular Dystrophy Myopathic mutation in muscle cytoskeleton protein DytrophinMuscle weaknessMyoglobinureaFasciculation (?)Increase in sarcoplasmic enzyme

Fasciculation is part of neurogenic disorder 131Disease of motor unit Carpal Tunnel syndromNeurogenic: change in motor neuron cell axons (peripheral nerve)Muscle atrophyFasciculation Decreased muscle tone

132Autonomic Nervous System Minute QuizIs autonomic system sensory or motor?Both

What is main purpose of autonomic system?Homeostasis

What are the divisions of autonomic system?Sympathetic, parasympathetic, enteric

Where are automatic motor neuron located?Outside the spinal cord, in groups called autonomic ganglia

ComparisonSympathetic Parasympathetic Fight or flight Increase heart beat and contraction Presynaptic: Ach Nicotinic receptor Postsynaptic: NE alpha/beta adrenergic

Rest and digest Decrease heart beat and contraction Presynaptic: Ach Nicotinic receptor Postsynaptic: Ach Muscarinic receptor

Sensory input VagusMost visceral information GlossopharyngealFacial Both synapses in the brain stem in nucleus of solitary tract

AmygdalaHypothalamusLimbic cortexNucleus of the solitary tractVisceral organsThe nucleus of the solitary tract integrates visceral sensory inputs and autonomic outputs and project to higher brain centers involved in homeostasis.Another minute quizHomeostasis is maintained through what type of feedback?Negative feedbackWhat is a Nucleus?Collection of neuron body in CNSWhat is equivalent of nucleus in the PNS?Ganglion Enteric system depends on sympathetic and parasympathetic system to functionNo, it receives input from them but can function alone Last one!Which CNS structures gives input to the autonomic system?HypothalamusBP and body temperature Electrolyte balance (thirst)Energy metabolish (hunger)Reproduction Response to stressLimbic system Visceral response to emotion AmygdalaCingulate cortex