Bio C Tau - Sensory And Motor Mechanisms (Ch.50)

Front 1

sensory receptors

Back 1

usually modified neurons or epithelial cells that occur singly or in groups within sensory organs

Front 2

sensory transduction

Back 2

The conversion of a physical or chemical stimulus to a change in the membrane potential of a sensory receptor. a graded change in the membrane potential of a receptor cell is proportional to the strength of the stimulus

Front 3

amplification

Back 3

The strengthening of stimulusenergy during transduction. Forexample, an action potential conducted from the eye to thehuman brain has about 100,000 times as much energy as thefew photons of light that triggered it.

Front 4

Transmission

Back 4

of receptor potential to the central nergvous system may occur either as a result of the generation of an action potential when the sensory receptor is a sensory neuron, or by the release of neurotransmitter from a receptor cell into a synspse with a sensory neuron, which then may transmit an action potential.

Front 5

sensory adaptation

Back 5

caused by continuous stimulation result in a decline in sensitivity of the receptor cell

Front 6

mechanoreceptors

Back 6

sensory receptros that respond to the mechanical energy of pressure, touch, stretch, motion, and sound. Bendin or stretching of the mechanoreceptor cell membrane increases its permeability to sodium and potassium ions, creating a receptor potential.

Front 7

muscle spindles

Back 7

stertch receptors that monitor the length of skeletal muscles

Front 8

Hair cells

Back 8

mechanoreceptors (motion detection) in the ear, when motion produces bending in the cilia or microvilli projecting from a hair cell, ion permeabilities either increase or decrease, and the rate of action potential firing changes.

Front 9

nociceptors

Back 9

also called Pain receptors. naked dendrites in the epidermis called nociceptors, different groups of receptors respond to exceess heat, pressure, or chemicals released by injured cells.

Front 10

eye cup

Back 10

in planarians, detect light intensity and direction, consists of receptor cells within a cup formed from darkly pigmented cells. Brain compared impulses to help the animal navigate a direct path away from a light source.

Front 11

compound eye

Back 11

contains up to thousnads of light detectors called ommatidia, each with its own lens. for example insect eyes.

Front 12

single-lens eye

Back 12

light is focused through the signle lens onto the retina containing light. for example humen eyes.

Front 13

choroid

Back 13

thin, pigmented inner layer of eye

Front 14

retina

Back 14

הרשתית

innermost layer, containts the photoreceptors cells, the optic nerve attaches to the eye at the optic disk, forming a blind spot on the retina

Front 15

lens

Back 15

עדשת העין

focuses an image onto the retina

Front 16

rod cells and cone cells

Back 16

the photoreceptors in the retina. The relative proportion of each of these receptors correlates with the activity pattern of the animal: Rods are more light sensitive and enable night vision, whereas cones distinguish colors. In the human eye, rods are most concentrated towart the edge of the retina, whereas the center of the visual field, the fovea, is filled with cones.

Front 17

receptor potential

Back 17

An initial response of a receptor cell to a stimulus, consisting of a change in voltage across the receptor membrane. proportional to the stimulus strength.

Front 18

sensory adaptation

Back 18

The tendency of sensory neurons to become less sensitive when they are stimulated repeatedly.

Front 19

statocysts

Back 19

To sense gravity and maintain equilibrium, most invertebratesrely on mechanoreceptors located in organs called statocysts

Front 20

Statolith

Back 20

in statocysts, granules formed by grains of sand or other dense materials,sit freely in a chamber lined with ciliated cells.

Front 21

outer ear

Back 21

consists of the external pinna and the auditory canal, which collect sound waves and channel them to the tympanic membrane (eardrum), which separates the outer ear from the middle ear.

Front 22

tympanic membrane

Back 22

עור התוף.

(eardrum) transmits sound waves to bones of the middle ear.

Front 23

middle ear

Back 23

three small bones—the malleus (hammer), incus (anvil), and stapes(stirrup)—transmit vibrations to the oval window, which is a membrane beneath the stapes.

Front 24

oval window

Back 24

In the vertebrate ear, a membrane-covered gap in the skull bone,through which sound waves pass from the middle ear to the inner ear.

Front 25

Eustachian tube

Back 25

The tube that connects the middle ear to the pharynx. equalizes pressure between the middle ear and the atmosphere

Front 26

inner ear

Back 26

consists of fluid-filled chambers, including the semicircular canals, which function in equilibrium, and the coiled cochlea (from the Latin meaning “snail”), a bony chamber that is involved in hearing.

Front 27

Cochlea

Back 27

שבלול האוזן.

The complex, coiled organ of hearing that contains the organ of Corti.

Front 28

semicircular canals

Back 28

A three-part chamber ofthe inner ear that functions in maintaining equilibrium.

Front 29

Organ of Corti

Back 29

The actual hearing organ of the vertebrate ear, located in the floor of the cochlear duct in the inner ear; contains the receptor cells (hair cells) of the ear.

Front 30

Vestibular canal\Tympanic canal

Back 30

The cochlea has two large canals—an upper vestibular canal and a lower tympanic canal—separated by a smaller cochlear duct. Both canals are filled with fluid.

Front 31

Basilar membrane

Back 31

Sound waves make the basilarme mbrane vibrate, which results in bending of the hairs anddepolarization of the hair cells.

Front 32

round window

Back 32

In the mammalian ear, the point of contact where vibrations of the stapes create a traveling series of pressure waves in the fluid of the cochlea.

Front 33

ommatidia

Back 33

(singular,Ommatidium) A compound eye (like insects eye) consists of up to several thousand light detectors called ommatidia.

Front 34

Pupil

Back 34

האישון

The opening in the iris, which admits light into the interior of the vertebrate eye. Muscles in the iris regulate its size.

Front 35

Iris

Back 35

הקשתית

By changing size, the iris regulates the amount of light entering the pupil.

Front 36

retinal

Back 36

(a derivative of vitamin A). The light-absorbing molecule in rods and cones of the vertebrate eye. Absorption of light shifts one bond in retinal from a cis to a trans arrangement,converting the molecule from an angled shape to a straight shape.

Front 37

Ganglion cell

Back 37

each ganglion cell gathers input from several bipolar cells.

Front 38

Bipolar cell

Back 38

Each bipolar cell receives information from several rods or cones

Front 39

Horizontal cell

Back 39

horizontal cells carry signals from one rod or cone to other photoreceptors and to several bipolar cells while doing lateral inhibition.

Front 40

Amacrine cell

Back 40

Amacrine cells distribute some information from one bipolar cell to several ganglion cells. Lateral inhibitionis repeated by the interactions of the amacrine cells with the ganglion cells and occurs at all levels of visual processing in the brain.

Front 41

opsin

Back 41

retinal bound to a membrane protein called an opsin. Seven α helices of each opsin molecules pan the disk membrane. The visualpigment of rods, shown here, is called rhodopsin.

Front 42

thin filaments

Back 42

Muscle cell contraction relies on the interaction betweenprotein structures called thin and thick filaments. two strands of polymerized actinare coiled around one another; similar actin structurescalled microfilaments function in cell motility.

Front 43

thick filaments

Back 43

are staggered arrays of myosin molecules.

Front 44

myofibrils

Back 44

contain the thin and thick filaments

Front 45

sarcomeres

Back 45

The myofibrils in muscle fibers are made up of repeatingsections called sarcomeres, which are the basic contractileunits of skeletal muscle.

Front 46

Tropomyosin

Back 46

The regulatory protein thatblocks the myosin-binding sites on actinmolecules.

Front 47

troponin complex

Back 47

The regulatory proteins that control the position of tropomyosin on the thin filament.

Front 48

T tubules

Back 48

transverse (T) tubules. An infolding of theplasma membrane of skeletal muscle cells.

Front 49

SR

Back 49

sarcoplasmic reticulum (SR). A specialized endoplasmicreticulum that regulates the calciumconcentration in the cytosol of muscle cells.

Front 50

motor unit

Back 50

A single motor neuron and all themuscle fibers it controls.

Front 51

tetanus

Back 51

When the rate is so high that the muscle fiber cannot relaxat all between stimuli, the twitches fuse into one smooth,sustained contraction called tetanus.