UNIT IX – HUMAN PHYSIOLOGY I - PowerPoint Presentation

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UNIT IX – HUMAN PHYSIOLOGY I

Baby Campbell – Ch 27, 32, 37, 38, 39Big Campbell – Ch 40, 45, 48, 49, 50

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I. ANIMAL PHYLOGENY

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I. ANIMAL PHYLOGENY

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I. ANIMAL PHYLOGENY, contShared Characteristics

eukaryotic multicellular heterotrophic Most are motile Lack cell walls/chloroplasts

Most have tissues, organsExtracellular MatrixHox

genes

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II. ANIMAL REGULATIONRegulators versus Conformers

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II. ANIMAL REGULATION, cont

HomeostasisFeedback ControlNegative Feedback

Positive Feedback

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II. ANIMAL REGULATION, contThermoregulation

EctothermsEndotherms

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II. ANIMAL REGULATION, contQ10

Used to show relationship between temperature and biological reaction/process Measure in the change in a factor for every 10 oC change in temperature

Calculate the Daphnia Q10 using the data provided below. Round to the nearest whole number.

Temp

(°C)

Resp

Rate (Breaths/Min)

16

16

21

28

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II. ANIMAL REGULATION, cont

Metabolism Sum of all energy-requiring biochemical reactionsEnergy measured in Joules, calories, or kilocalories (Calories)Metabolic rate may be determined by Monitoring rate of heat loss

Measuring amount of O2 consumed or CO2 produced

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II. ANIMAL REGULATION, cont

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II. ANIMAL REGULATION, contAdaptations

Torpor Hibernation—cold temperaturesEstivation—dry and hot

Brown Fat—non-shivering thermogenesis

InsulationBehavioral Responses

Countercurrent Heat Exchangers

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III. INTRODUCTION TO HUMAN PHYSIOLOGYFour Types of Tissue

Epithelial—2D sheets, lines organs and secretes/absorbs Connective—space-filling, surrounded by ECM Muscular—contracts for movement

Nervous—conducts impulses

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III. INTRO TO HUMAN PHYSIOLOGY, cont

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NERVOUS SYSTEM

Phineas Gage

1823 - 1860

Dr. Rufus Weaver & Harriet Cole

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I. HUMAN NERVOUS SYSTEM

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II. CELLS OF THE NERVOUS SYSTEMGlia Support cells

Mostly non-conducting cells that provide support, insulation, protectionTypesAstrocytesMicroglia

Oligodendrocytes / Schwann CellsMyelin sheaths

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II. CELLS OF THE NERVOUS SYSTEM, contNeuron Basic unit of function

Three typesAfferent NeuronsSensory neurons impulse toward CNSEfferent Neurons

Motor neurons impulse toward muscles, extremities

Interneurons integrates, connects afferent and efferent neurons

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II. CELLS OF THE NERVOUS SYSTEM, cont

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III. NEURAL SIGNALINGA Closer Look at a Neuron Dendrite

Cell Body Axon Myelin SheathNodes of RanvierSaltatory ConductionAxon (Synaptic) Terminal

Synapse

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III. NEURAL SIGNALING, contMembrane Potential

Due to selective permeability of plasma membrane High concentration of Na + outside, K+ insideMaintained by Na/K Pump, channels Net negative charge of about -70mV

Known as resting potential

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III. NEURAL SIGNALING, contGated Ion ChannelsChannels that open/close in response to a stimulusSeen in neurons, muscle cells

HyperpolarizationOpening of DepolarizationOpening of Action Potential

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III. NEURAL SIGNALING, contThreshold

Stimulus strong enough to increase voltage to ~ -50mVAction Potential triggeredSequence of EventsResting StateStimulus

DepolarizationNa+ channels open

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III. NEURAL SIGNALING, contRepolarization

Na+ channels close; K+ channels open slowlyK+ ions leavecell returns to negative

HyperpolarizationAlso known as undershootK+

gates close very slowly → K+ ions continue flowing out of cell Results in brief period where cell is more negative than resting stateKnown as refractory period

; neuron is insensitive to depolarization until resting potential is restored

Resting potential restored by Na-K Pump

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III. NEURAL SIGNALING, contMovement of the action potential is self-propagating

Regeneration of “new” action potentials only after refractory periodForward direction onlySpeed of action potential related toAxon diameterSaltatory conduction

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III. NEURAL SIGNALING, contNerve Impulse Transmission - A Review

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III. NEURAL SIGNALING, contChemical SynapsesImpulses are transmitted across the synaptic cleft by chemicals known as neurotransmitters

When action potential reaches axon terminal,Depolarization triggers opening of Ca2+ gated channelsCa2+ ions diffuse into axonResults in fusion of vesicles containing neurotransmitters with axon terminal membrane

Neurotransmitters “spit out”; diffuse across synapse

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III. NEURAL SIGNALING, contNeurotransmitters received by protein receptors on post-synaptic cell. Categorized based on effect:Excitatory Post-Synaptic Potentials (EPSPs)

Inhibitory Post-Synaptic Potentials (IPSPs)

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III. NEURAL SIGNALING, cont

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AF

CEDB

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IV. ORGANIZATION OF HUMAN NERVOUS SYSTEM

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IV. ORGANIZATION, contReflex Arc

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V. CENTRAL NERVOUS SYSTEMConsists of

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V. CNS, contHuman Brain

ForebrainCerebrumCerebral CortexCorpus CallosumThalamusHypothalamus

Midbrain – Receives & transmits sensory info to forebrainHindbrain

CerebellumPonsMedulla oblongata

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V. CNS, cont

A Closer Look at the Cerebral Cortex

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V. CNS, contThe Limbic System

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VI. PERIPHERAL NERVOUS SYSTEM

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VI. PNS, contNerves

Bundles of sensory & motor neurons12 pairs of cranial nerves 31 pairs of spinal nerves

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VII. SKELETAL MUSCLE FUNCTIONMuscle tissue → muscle fibers → myofibrils → myofilamentsTwo types of

myofilamentsThin FilamentsTwo strands of actin Thick filamentMyosinSarcomeres

Sliding Filament Model

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VII. SKELETAL MUSCLE

FUNCTION,cont

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VII. SKELETAL MUSCLE FUNCTION, cont

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VII. SKELETAL MUSCLE FUNCTION, contRegulationDue to interactions of calcium, tropomyosin

Relaxation Tropomyosin blocks myosin binding sites on actinHeld in place by troponin complexContractionWhen

Ca is available, it binds to troponin complexTropomyosin shifts Myosin binding sites are exposed

Muscle can contract

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VII. SKELETAL MUSCLE FUNCTION, cont

Sliding Filament ModelMyosin binds ATP; hydrolyzed to ADP + PiMyosin head changes shape; termed high energy configurationMyosin head binds to specific site on actin; forms a cross bridgeADP and P

i released; myosin relaxes to low energy configurationCauses actin to slide toward center of sarcomereBinding of new ATP releases myosin head

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VII. SKELETAL MUSCLE FUNCTION, contFast-twitch Fibers

Slow-twitch FibersEnergy Availability AdaptationsCreatine PhosphateMyoglobin

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VII. SKELETAL MUSCLE FUNCTION, cont

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ENDOCRINE SYSTEM

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I. INTRODUCTION TO ENDOCRINE FUNCTIONGlands may be Exocrine

EndocrineTarget

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I. INTRO, contNegative Feedback

Positive Feedback

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I. INTRO, cont

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II. TYPES OF HORMONESWater-Soluble HormonesHydrophilicMost common

Signaling involves three key events:ReceptionSignal TransductionResponse

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II. TYPES OF HORMONES, contSteroidsDerived from cholesterol

Include sex hormonesSmall, nonpolar hormones that diffuse through cell membrane

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III. GLANDS OF THE ENDOCRINE SYSTEMPosterior Pituitary GlandOxytocin

Antidiuretic Hormone (ADH)

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IV. GLANDS OF THE ENDOCRINE SYSTEMAnterior Pituitary GlandTropic Hormones

FSHLHACTHTSH

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IV. GLANDS OF THE ENDOCRINE SYSTEMAnterior Pituitary Gland, cont

Growth HormoneGigantismDwarfism/acromegaly

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III. ENDOCRINE SYSTEM GLANDS, contPineal Gland

Melatonin Thyroid GlandThyroxine

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III. ENDOCRINE SYSTEM GLANDS, contThyroid Gland,

contCalcitonin Parathyroid Gland:PTH

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III. ENDOCRINE SYSTEM GLANDS, contPancreasInsulin

Produced by beta cells of Islets of LangerhansGlucagonProduced by alpha cells of Islets of Langerhans

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III. ENDOCRINE SYSTEM GLANDS, contPancreas

Type I DiabetesInsulin-dependentAutoimmune disorderType II DiabetesNon-insulin-dependentReduced responsiveness in insulin targetsGestational Diabetes

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III. ENDOCRINE SYSTEM GLANDS, contAdrenal GlandsAdrenal Medulla

(catecholamines)Epinephrine/ NorepinephrineAdrenal Cortex (corticosteroids) Cortisol → Raises blood glucose via fat/protein metabolismAldosterone → Stimulates kidneys to ↑ reabsorption of Na+, water follows

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III. ENDOCRINE SYSTEM GLANDS, contAdrenal Gland, cont

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III. ENDOCRINE SYSTEM GLANDS, contTestes/Ovaries