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SENSORYMECHANISMS AND

MOTOR SKILLS

Huhuhuhu

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SENSATION

oconverting energy into a change in the membrane potof sensory receptors

oaction potentials

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SENSORY PATHWAYS

Functions Reception

Detection of stimuli

Sensory receptorsstimuli detector

Transmit signals to CNS

Transduction

conversion of stimulus energy into a change in the membrane potential of a sensory receptor Receptor potentialchange in membrane potential

Transmissionto action potential to CNS

Integrationof sensory information

Some are integrated through summation

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PERCEPTION

oBrains construction of the stimuli

oThe brain distinguishes the stimuli by the area of the brain that receivaction potentials

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AMPLIFICATION

Strengthening of stimulus energy

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SENSORY ADAPTATION

Decrease in responsiveness to continued stimulation

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SENSORY RECEPTORS

oMechanoreceptorssense physical deformation caused by stimuli(pressure, stretch, motion, sound)oDendrites of sensory neurons

oChemoreceptorstransmit information about total solute concentratsolutiono

When bound to a stimulus molecule, it becomes more or less permeable to solution

oElectromagnetic receptorsdetect electromagnetic energy (light, elemagnetism)oPhotoreceptorsdetect light

oInfrared receptorsdetect body heat

oMagnetic receptorsdetect magnetic fields

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SENSORY RECEPTORS

Thermoreceptors- respond to heat or cold Maintain body temperature

Pain receptorsnociceptors Naked dendrites in epidermis

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EX. HEARING ANDEQUILIBRIUM

Mechanoreceptors produce receptor potentials Detect moving particles and settling particles

Statocystssensory organ that maintain equilibrium Statolithsmechanoreceptors that detect movement of granules

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IN THE EAR

Three bones in the ear transmit vibrations to cochlea(can distinguish which then travels to vestibular canal Bending of hair

Volumeamplitude of sound wave

Pitchfrequency

Inner Eardetect equilibrium Utricle and sacculehave otoliths (granules that detect gravity and linear movemen

3 semicircular canalscontain fluid & detects angular acceleration

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IN THE EAR OF FISHES

Lateral line System Mechanoreceptors that sense water movement

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TASTE AND SMELL YUM

Terrestrial animals Gustation(taste)tastants

Olfocation(smell)odorants

Aquatic animalsno distinction

InsectsSensillahair on feet and mouth

HumansTaste Buds (sweet, sour, salty, bitter, umami) through tongu Olfactory sensory cellsneurons that line nasal cavity

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VISION

Invertebrateslight-detecting organ Image-forming eyes

Compound eyesinsects and crustaceans (have ommatidiathousand light detectors)

Single-lens eyescamera-like (iris changes diameter of pupil)

Vertebrateseye detects color and light; brain assembles image

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VERTEBRATE EYE

Structure Sclerawhite outer layer (includes cornea)

Choroidpigmented layer

Irisregulates size of pupil

Retinacontains photoreceptors; where visual information processing begins

Lensfocuses light on the retina

Optic Diskblind spot in retina where optic nerve attaches

DivisionsAnterioraqueous humor (produced by ciliated body) ; watery

Posteriorvitreous humor; jelly-like

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HUMAN EYEPHOTORECEPTORS

Rodslight-sensitive No colors

Concentrated around retina

Rhodopsin- changes shape when absorbing light.

Conescolor sensitive

Not light Concentrated on fovea(center of visual field)

Contain retinal(light-absorbing molecule) bonded to opsin

Hyperpolarizes the cell

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PHOTOPSINS

3 pigments that detect light of different wave lengths

Red

Green

Blue

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MUSCULAR SYSTEM ALMOST

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SARCOMERE

ofunctional unit of muscle

oBordered by Z lines

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SLIDING FILAMENT MODEL

Filaments overlap between thin and thick filaments Interaction of myosin and actin (form a cross bridge)

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VERTEBRATE SKELETALMUSCLEoStriated Muscles

oConsists of long fibersoBundle of Myofibrils

oMyofilaments

oThin2 strands of actin, 1 strand of regulatory protein

oThickarrays of myosin molecules

oContracts only when stimulated by a motor neuronoTropomyosinprotein that blocks binding sites when muscle is at res

oMyosin-binding sitesexposed when Ca is released

oAcetylcholinecauses muscle to produce an action potential (depolait)

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Action

potentials

Interior of

muscle fiber

Transvers

e tubules

Sacroplasmic

reticulum

releases Ca

Binds to troponin

complex

Exposes myosin binding

sites

Cross bridge

cycle

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2 MECHANISMS THAT THENERVOUS SYSTEM PRODUCECONTRACTIONS1. Number of fibers that contract

2. Rate at which fibers are stimulated

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MOTOR NEURONS

Recruitmentthe more neurons = stronger contractions

Tetanusstate of smooth & sustained contraction

Twitchproduced by one motor neuron Slow-twitch fiberscontract slowly

Sustain longer contractions

All are oxidative Fast-twitch fiberscontract rapidly

Sustain short contractions

Glycolytic or oxidative

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TYPES OF SKELETALSYSTEM

Hydrostatic skeletons (lack hard parts) Consist of fluid held under pressure in a closed body compartment

In cnidarians, flatworms, annelids (use hydrostatic skeleton for peristalsis) and nem

Exoskeletonin arthropods (usually made of chitin)

Endoskeletonbones

In sponges, echinoderms and chordates Humans = 200 bones

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CHARACTERISTICS

Excitability

Contractility

Elasticity

Extensibility

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FUNCTION

Movement

Visceral Action

Positioning

Heat production

Electricity (in some fishes)

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ORGANIZATION

Sarcolema

Sarcoplasm

Nuclei

Striations

Epimysium

Perimysium

Endomysium

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TENDONS

Attachments of muscles to bones

Aponeuroses (flattened sheets)

Fascia (wrapper)

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SUBMICROSCOPICALLY

Mitochondria

Sarcoplasmic reticulum

Transverse tubules

Triad

Thick and thin filaments

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ORGANIZATION

Red vs White

Somatic vs Visceral

Voluntary vs Involuntary

Smooth vs skeletal vs cardiac

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HISTOLOGY

Skeletal

With striations andcrossbands

Voluntary

Multi-nucleate

Myofibrils

Innervated by a branch ofsingle nerve cell

Cardiac (Heart)

With striationsbvlhfkjhfjkhdfjkh

Involuntary

Mono-nucleate

Intercalated Discs

Branched

Smooth

No striationsbvlfgfghfkjhf

Involuntary

Mono-nuclea

Visceral Fun

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NEUROMUSCULAR JUNCTIO

Connection between nervous system and muscle fiber

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MUSCLE METABOLISM

Energy fromATP

Creatine phosphate

Glycolysis

Aerobic cellular respiration

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MUSCLE FUNCTION

Importance of Length

Color Red: high myoglobin and vascularization

White: reverse of red

Tonic & Twitch Fibers

Force: Active and Elastic

SO vs FOG vs FG

Strength depends on cross sectional area

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MUSCLE FUNCTION

Graded force Excitation: all or none

Recruitment

Summation

Tetanus

Fiber Arrangement: pinnate or parallel

Bone Musce Lever Systems Where muscles are attached matters

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MUSCLE MECHANICS

Motor Patternany repetitive movement caused by nervous system

Synergists

Antagonists

Prime Movers

Originfixed pointInsertionarea of motion

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SOME ACTIONS

Flexion & Extensions

Adductors & Abductors

Levators and Depressors

Protactors and Retractors

Supinators and Pronators

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MUSCLE HOMOLOGIES

Determined by Similarity in location

In origin and insertion

In function

Shape

In nervous innervation

Origin/insertionAction

size

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BASIS OF NAMING MUSCLE

Direction of fibers

Location or position

Number of Divisions

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MUSCLES IN AQUATICVERTEBRATES

Lampreysno lateral septum Myomeres inserted into myosepta

No appendicular muscles

Gnathostome fish Strong axial musculature

Myomeres become angled and ov

Hypobranchial muscles open the j

Appendicular muscles with fins

Dorsal mass- extensors/adductors/levator

Ventral mass- flexors, abductors, depress

Constrictors continuous over the g

Adductor mandibulae closes the ja

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TETRAPODS

Limb muscles increase and axial musculature decreases

Myospeta disappear except in anurans

Epaxial muscles decrease in prominence Neck muscles form layers for flexibility

Intervertebrals

Longissimus Spinales

iliocostales

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TETRAPODS

Hypaxial muscles of trunk Subvertebral group-trunk flexion

Rectus abdominus group- supports the viscera

Lateral group- three sheet like layers; from which serratus, levascapulae and rhomboideus evolved External oblique

Internal oblique

Transversus abdominus

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BRANCHIAL MUSCLES

Involved in feeding and breathing

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HYPOBRANCHIAL MUSCLES

Head, neck, and tongue movement

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APPENDICULAR MUSCLES

Large for propulsion in tetrapods

In fish: for balance and stability

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LOCOMOTION

Primary SwimmersUndulatory

Secondary Swimmers - Paddles

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Terrestrial Cursorialfast running

Saltatorial - hop

Scansorialfor climbing

Fossorial - diggers

Flight Parachuting

Gliding

True flight