Bio 110 Lec Chapter 50 Sensory And Motor Mechanisms

Front 1

Sensation

Back 1

- action potentials that reach brain via sensory neurons

Front 2

Perception

Back 2

- interpretation of stimulus

- e.g. smells, sounds

Front 3

Sensory reception

Back 3

- ability of a cell to detect energy of a stimulus

Front 4

Sensory receptor

Back 4

- structures that transmit information about changes in animal's internal and external enviornment

- usually modified neurons or epithelial cells occuring singly or within groups in sensory organs

- convert stimuli energy into changes in membrane potentials -> transmit signals to nervous system

Front 5

Exteroreceptors

Back 5

- type of sensory receptor

- detects external stimuli: heat, pressure, light, chemicals

Front 6

Interoreceptors

Back 6

- type of sensory receptor

- detects internal stimulI: BP and body position

Front 7

Sensory transduction

Back 7

- conversion of stimulus energy into a change in membrane potential of receptor cell

- stimulus energy changes membrane permeability -> receptor potential

Front 8

Receptor potential

Back 8

- graded change in membrane potential that results from stimulus energy changing membran permeability

Front 9

Amplification

Back 9

- results when stimulus energy is too weak to be carrie into nervous system

- in accessory structures/part of transduction process

Front 10

Transmission

Back 10

- sensation transmitted to CNS, to ways

(1) receptor cell is sensory neuron -> receptor potential changes frequency of action potentials that reach CNS

(2) receptor cell transmits neurotransmitters, which affects action potential generated by ensory neuron

Front 11

Integration

Back 11

- summation of graded potentials

Front 12

Sensory adaptation

Back 12

- decrease in sensitivity during continued stimulation

- selective information is sent to CNS

Front 13

Mechanoreceptors

Back 13

- SR1

- stimulated by physical deformation caused by mechanical energy

- bending plasma membrane -> increased permeability to Na+ and K+ -> receptor potential

- Pacinian corpuscles: strong pressure

- Meissner's corpuscles and Merkel's disc: light touch

Front 14

Muscle spindle

Back 14

- stretch receptor, part of SR1

- monitor length of skeletal muscles, as in reflex arc

Front 15

Hair cell

Back 15

- part of SR1

- detects motion

Front 16

Pain receptor

Back 16

- nociceptors

Front 17

Nociceptor

Back 17

- class of naked dendrites that function as pain receptors

- prostaglandins lower receptr threshold -> increase pain

- aspirin and ibuprofen inhibit prostaglandid synthesis

Front 18

Thermoreceptor

Back 18

- respond to heat or cold to regulate body temperature

- eiither two receptors comprsising of encapsulated dendrites, or naked dendrites of sensory nnneurons

- in hypothalamus: function as primary temperature control

Front 19

Chemoreceptor

Back 19

- sense total solute concentration

- respond to individual molecules

- respond to categories of related chemicals (e.g. olfactory receptors)

Front 20

Gustatory receptor

Back 20

- facilitate sensation of taste

- mediated by chemoreceptors

Front 21

Olfactory receptor

Back 21

- facilitate sensation of spell

- medicated by chemoreceptors

Front 22

Electromagnetic receptor

Back 22

- responds to electromagnetic radiation (e.g. photoreceptors, electricity, magnetoreceptors)

Front 23

Photoreceptor

Back 23

- facilitate sensation to light

- mediated by electromagnetic receptors

- most, if not all, homologous in animals

Front 24

Eye cup

Back 24

- single light receptor in planarians

- responds to eye intensity and direction without forming an image

- two eye cups and two images on left and right

- brain compares rate of nerve impulses and determines which direction to turn -> until impulses from each cup equal and minimal

Front 25

Compound eyes

Back 25

- type of image-forming eye evolved in invertebrates (insects, crustaceans, some polychaete worms)

- mosaic image more acute at detecting movement

- contains thousands of light receptors, each with own cornea and lens

Front 26

Ommatidia

Back 26

- light detector in compound eye

- in superimposition eyes,lenses work as prisms and parabolic mirros, focusing light to photoreceptor

Front 27

Single-lens eye

Back 27

- type of image-forming eye evolved in inertebrates (jellies, polychaetes, spiders, many mollusks) and vertebratess

- one eye focuseslight onto retina

Front 28

Sclera

Back 28

- tough outer layer of vertebrate eye

Front 29

Choroid

Back 29

- thin inner pigmented layer of vertebrate eye

Front 30

Conjunctiva

Back 30

- thin layer of cells that covers sclera and keeps eye moist

Front 31

Cornea

Back 31

- in front

- transparent area of sclera

- allows light to enter eye and act as fixed lens

Front 32

Iris

Back 32

- pigmented

- regulates amount of light entering pupil

Front 33

Pupil

Back 33

- hole in center of iris

Front 34

Retina

Back 34

- innermost layer of eyeball

- contains photoreceptor cells which transmit signals from optic disc where nerve attaches

Front 35

Lens

Back 35

- divide eye into two chambers

Front 36

Ciliary body

Back 36

- divides eye into two chambers

- produces aqueous humor

Front 37

Aqueous humor

Back 37

- fills cavity between lens and cornea

- helps focus light onto retina

Front 38

Vitreous humor

Back 38

- fills cavity behind lens

- comprises most of eye's volume

- helps focus light onto retina

Front 39

Accommodation

Back 39

- process by which lens changes shape to focus image onto retina

- near: nearly spherical, flat: distance

- controlled by ciliary muscle

Front 40

Rod cells

Back 40

- photoreceptor of eye with stack of folded membranes in which visual pigments are embedded

- sensitive to light but do not distinguish colors

- greatest density around peripheral regions

Front 41

Cone cells

Back 41

- photoreceptor of eye with stack of folded membranes in which visual pigments are embedded

- responsible for daytime color vision

- most dense at fovea

Front 42

Fovea

Back 42

- ceter of visual field

- no rod cells

Front 43

Retinal

Back 43

- light-absorbing visual pigment synthesized from vitamin A

- bound to opsin, in rod cells, makes rhodopsin

Front 44

Opsin

Back 44

- membrane protein visual pigment

- binds to retinal

Front 45

Rhodopsin

Back 45

- when rod cell optin combines with retinal

- (1) absorbs light (2) retinal changes shape (3) photoreceptor cell membrane gets hyperpolarized (4) chemical signal tp ce;;s decreases

- gets "bleached" due to light-induced change: rods become unresponsive and cones take over in bright light

- retinal is converted to original form in dark

Front 46

Photopsins

Back 46

- one for red, green, and blue cones

- associates with retinol

Front 47

Biopolar cells

Back 47

- neurons that receve signals from rod and cone cell axons

- vertical pathway: receptor -> bipolar -> ganglion

Front 48

Ganglion cells

Back 48

- are synapsed by bipolar cells

Front 49

Horizontal cells

Back 49

- neuron in retina that helps integrate information

- in lateral pathway of photoreceptor signals, carries signals from one rod or cone to other receptor cells and several bipolar cells

Front 50

Amacrine cells

Back 50

- in lateral pathwa of photoreceptor signals, spreads signals from one bipolar cells to several ganglion cells

Front 51

Lateral inhibition

Back 51

- when horizontal cells stimulate nearby receptors but inhibitmore distant/non-illuminated bipolar cells

- enhance contrast

- sharpens edges

- at all levels of visual processing!

Front 52

Optic chiasm

Back 52

- where optic nerves from each eye meet

- arranged such that viewed left -> transmitted to right side of brain; vice versa

- additional neurpms carry info to more sophisticated visual processing centers in cortex

Front 53

Lateral geniculate nuclei

Back 53

- from optic chiasm, connect ganglion axons to halamus, then to primary visual cortex

Front 54

Primary visual cortex

Back 54

- connected to thalamus, which is connected to ganglion axons

- in occipital lobe of cerebrum

Front 55

Outer ear

Back 55

- collect sound waves in external pinna and auditory canal

Front 56

Tympanic membrane

Back 56

- where sound waves are channeled after being collected by outer ear

- transmits waves to malleus, incus, and stapes

- in insect legs

Front 57

Middle ear

Back 57

- opens into Eustachian tube

- contains tympanic membrane

Front 58

Malleus

Back 58

- small bone which amplifies and transmits mechanical movements of tympanic membrane to oval window

Front 59

Incus

Back 59

- small bone which amplifies and transmits mechanical movements of tympanic membrane to oval window

Front 60

Stapes

Back 60

- small bone which amplifies and transmits mechanical movements of tympanic membrane to oval window

Front 61

Oval window

Back 61

- membrane of cochlea surface

- vibrations produce pressure waves in endolymph in coiled cochlea of inner ear

Front 62

Eustachian tube

Back 62

- where middle ear opnes

- channel to the pharynz which aids in pressure equalization on both sides of tympanic membrane

Front 63

Inner ear

Back 63

- contains coiled cochlea, semicircular canals, and vestibule

Front 64

Cochlea

Back 64

- floor of duct is formed by basilar membrane

Front 65

Organ of Corti

Back 65

- attached to cochlea

- contains receptor hair cells

- (1) hair cells bend against tectorial membrane (2) hair cells are depolarized (3) hair cells release a neurotransmitter that triggers an action potential in sensory neuron (4) carries sensations to brain

- greater amplitude -> more vigorous vibrations -> more bending of hair cells -> more action potentials

Front 66

Round window

Back 66

- where pressure wave is dissipated after it continues through tympanic canal

Front 67

Pitch

Back 67

- sound wave frequency

Front 68

Utricle

Back 68

- chamber in vestibule that opens to three semicircular canals

- hair cells project into gelatinous material containin numerous otoliths (small CaCO3 particles)

- otoliths: heavier than endolymph, so pulled down on hairs of receptor cells -> action potentials indicate hair position

Front 69

Saccule

Back 69

- one of two chambers in vestibule (behind oval window)

- hair cells respond to changes in head position with respect to gravity and movement in one direction

Front 70

Semicircular canals

Back 70

- detect rotation of head due to endolymph movement against hair cells

- for balance!

Front 71

Lateral line system

Back 71

- detects pressure waves in fishes and aquatic amphibians

- runs along both sides of body

Front 72

Neuromast

Back 72

- mechanoreceptor in lateral line system which contains hair cell clusters

- hairs embedded in cupula: gelatinous cap

- water: (1) pores (2) tube of lateral line system (3) past neuromasts (4) water pressure bends cupula, causing action potential

- provides information about movement direction, velocity of water currents, and movements/vibrations of predators and prey

Front 73

Statocysts

Back 73

- mechanoreceptor in invertebrates thatfunctions in sense of equilibrium

- located in: bell fringe of jellies, antennule bases in lobsters and crayfish

Front 74

Statoliths

Back 74

- dense granules in statocysts that settle in low point of a chamber, stimulating hair cells

Front 75

Taste buds

Back 75

- chemoreceptor cells for taste in humans and other animals

- sweet, sour, salty, bitter -> distinct regions, separate receptor molecules

- different from olfaction, but interact

Front 76

Locomotion

Back 76

- in mobile animals

- allows them to acquire food, escape from predators, or find mates

- based on contractile systems of microfilaments and microtubules

- swimming, running, flying

- requires energy to overcome friction and gravity

Front 77

Hydrostatic skeleton

Back 77

- fluid held under pressure in a closed body compartment

- e.g. cnidarians, flatwoms, nematodes, annelids

- muscles change shape of fluid-filled compartments

- provide no protection!

Front 78

Peristalsis

Back 78

- rhythmic locomotion of earthworms and other annelids

Front 79

Exoskeleton

Back 79

- hard encasement deposited on surface of animal

- shed as aimals grow

Front 80

Cuticle

Back 80

- exoskeleton is cuticle produced by epidermis

Front 81

Chitin

Back 81

- comprises exoskeleton

Front 82

Endoskeleton

Back 82

- hard supporting elements buried within soft tissues of an animal

- sponges: hard spicules of inorganic material or softer protein fibers

- echinoderms: ossicles composed of magnesium/calcium carbonate forming hard plates beneath skin

- chordates: cartilage and/or bone skeletons; vertebrates: axial and appendicular

Front 83

Skeletal muscle

Back 83

- bundles of long fiber running length of muscle

- attached to bones

- responsible for their movement

- skeletal muscle > fiber (single cell with many nuclei) > myofibrils > myofilaments

Front 84

Myofibrils

Back 84

- bundles composing skeletal muscle fiber

- arranged longitudinally

Front 85

Myofilaments

Back 85

- two kinds in each myofibril: thick and thin

Front 86

Thin filaments

Back 86

- 2 actin, 1 regulatory protein coiled together

Front 87

Thick filaments

Back 87

- staggered arrays of myosin molecules

- in clams, contain paramyosin, which allows muscles to stay in a fixed state of contraction for up to a month

Front 88

Sarcomere

Back 88

- unit of organization of skeletal muscle

- ZIAH

Front 89

Z lines

Back 89

- borders of sarcomere arranged in adjacent myofibrils

Front 90

I band

Back 90

- areas near edge of sarcomere

- only thin filaments

Front 91

A band

Back 91

- where thick and thin filaments overlap

- correspond to length of thick filaments

Front 92

H zone

Back 92

- areas in center of A bands containing only thic filaments

Front 93

Sliding-filament model

Back 93

- muscle contraction that reduces length of each sarcomere

- thin filaments ratchet across thick filaments, pulling Z lines together

- successive cross-bridges formed

Front 94

Cross-bridge

Back 94

- myosin on thick filaments attaches to actin on thin filaments, forming a cross-bridge

- cross-bridge bends inwards, pulling thin filament towards center, breaking cross-bridge, and forming new cross-bridge further down

- energy comes from hydrolysis of ATP by had region of myosins

Front 95

Phosphagens

Back 95

- unit of most energy storage in muscles

- in vertebrates, can provide phosphate group to ADP to make ATP through creatine phosphate

Front 96

Creatine phsophate

Back 96

- transfers phosphate to ADP to form ATP and creatine

Front 97

Tropomyosin

Back 97

- regulatory protein strand in thin filament that blocks myosin-binding sites

- contraction cycle

(1) wave of depolarization spreads rapidly in muscle

(2) depolarization of sarcoplasmic reticulum -> releases Ca2+

(3) calcium ions bind to troponin, causing thin filament to change shape and expose myosin-binding site -> muscle contracts

(4) sarcoplasmic reticulum pumps calcium out, tropomyosin-troponin complex blocks binding sites again

Front 98

Troponin complex

Back 98

- blocks myosin binding at each binding site

Front 99

Sarcoplasmic reticulum

Back 99

- specialzied endoplasmic reticulum of muscle cells

Front 100

T (transverse) tubules

Back 100

- infoldings in muscle cell plasma membrane through which depolarization initially spreads

Front 101

Tetanus

Back 101

- sustained muscle contraction

- vs. jerky actions of muscle twitches

Front 102

Motor unit

Back 102

- single motor neuron and all muscle fibers it controls

- all fibers contract as a group when motor neuron fires

Front 103

Recruitment

Back 103

- summation of multiple motor unit activity that causes graded contractions of skeletal muscles

Front 104

Fast muscle fiber

Back 104

- short duration twitches

- used in fast muscles for rapid, powerful contractions

Front 105

Slow muscle fiber

Back 105

- longer-lasting twitches

- less sarcoplasmic reticulum, so Ca2+ remains in cytoplasm longer

- maintain posture

- havemany mitochondria, rich blood supply, and myoglobin

Front 106

Cardiac muscle

Back 106

- found only in heart

- striated

- junctions between branched muscle cells contain intercalated discs

- action potentials last up to 20 times longer and have long refractory periods

Front 107

Intercalated discs

Back 107

- electrically couple all heart muscle cells, allowing coordinated action

Front 108

Smooth muscle

Back 108

- lack striations

- contain less myoosin, which is not associated with specific actin strands

- can contract over a greater range of lengths

- no transverse tubule system oor well-developed sarcoplasmic reticulum

- calcioum enters cytoplasm through plasma membrane