Ap Biology Chapter 49 Vocabulary

Front 1

A band

Back 1

The broad region that corresponds to the length of the thick filaments of myofibrils.

Front 2

accommodation

Back 2

The automatic adjustment of an eye to focus on near objects.

Front 3

amacrine cell

Back 3

A neuron of the retina that helps integrate information before it is sent to the brain.

Front 4

amplification

Back 4

The strengthening of stimulus energy that is otherwise too weak to be carried into the nervous system.

Front 5

aqueous humor

Back 5

Plasma-like liquid in the space between the lens and the cornea in the vertebrate eye; helps maintain the shape of the eye, supplies nutrients and oxygen to its tissues, and disposes of its wastes.

Front 6

bipolar cell

Back 6

A neuron that synapses with the axon of a rod or cone in the retina of the eye.

Front 7

cardiac muscle

Back 7

A type of muscle that forms the contractile wall of the heart. Its cells are joined by intercalated disck that relay each heartbeat.

Front 8

chemoreceptor

Back 8

A receptor that transmits information about the total solute concentration in a solution or about individual kinds of molecules.

Front 9

chitin

Back 9

A structural polysaccharide of an amino sugar found in many fungi and in the exoskeletons of all arthropods.

Front 10

choroid

Back 10

A thin, pigmented inner layer of the vertebrate eye.

Front 11

ciliary body

Back 11

A portion of the vertebrate eye associated with the lens. It produces the clear, watery aqueous humor that fills the anterior cavity of the eye.

Front 12

cochlea

Back 12

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

Front 13

compound eye

Back 13

A type of multifaceted eye in insects and crustaceans consisting of up to several thousand light-detecting, focusing ommatidia; especially good at detecting movement.

Front 14

cone cell

Back 14

One of two types of photoreceptors in the vertebrate eye; detects color during the day.

Front 15

conjunctiva

Back 15

A mucous membrane that helps keep the eye moist; lines the inner surface of the eyelid and covers the front of the eyeball, except the cornea.

Front 16

cornea

Back 16

The transparent frontal portion of the sclera, which admits light into the vertebrate eye.

Front 17

electromagnetic receptor

Back 17

A receptor of electromagnetic energy, such as visible light, electricity, and magnetism.

Front 18

endoskeleton

Back 18

A hard skeleton buried within the soft tissues of an animal, such as the spicules of sponges, the plates of echinoderms, and the bony skeletons of vertebrates.

Front 19

Eustachian tube

Back 19

The tube that connects the middle ear to the pharynx.

Front 20

exoskeleton

Back 20

A hard encasement on the surface of an animal, such as the shell of a mollusc or the cuticle of an arthropod, that provides protection and points of attachment for muscles.

Front 21

exteroreceptor

Back 21

A sensory receptor that detects stimuli outside the body, such as heat, light, pressure, and chemicals.

Front 22

eye cup

Back 22

A simple light-detecting organ in planarians that provides information about light intensity and direction but does not form images.

Front 23

fast muscle fibers

Back 23

Muscle cells used for rapid, powerful contractions.

Front 24

fovea

Back 24

An eye’s center of focus and the place on the retina where photoreceptors are highly concentrated.

Front 25

ganglion cell

Back 25

A type of neuron in the retina that synapses with bipolar cells and transmits action potentials to the brain via axons in the optic nerve.

Front 26

gustatory receptor

Back 26

Taste receptor.

Front 27

hair cell

Back 27

A type of mechanoreceptor that detects sound waves and other forms of movement in air or water.

Front 28

horizontal cell

Back 28

A neuron of the retina that helps integrate information before it is sent to the brain.

Front 29

hydrostatic skeleton

Back 29

A skeletal system composed of fluid held under pressure in a closed body compartment; the main skeleton of most cnidarians, flatworms, nematodes, and annelids.

Front 30

I band

Back 30

The area near the edge of the sarcomere where there are only thin filaments.

Front 31

incus

Back 31

The second of the three middle ear bones.

Front 32

inner ear

Back 32

One of three main regions of the vertebrate ear; includes the cochlea, organ of Corti, and semicircular canals.

Front 33

integration

Back 33

The interpretation of sensory signals within neural processing centers of the central nervous system.

Front 34

intercalated disk

Back 34

A specialized junction between cardiac muscle cells that provides direct electrical coupling between cells.

Front 35

interoreceptor

Back 35

A sensory receptor that detects stimuli within the body, such as blood pressure and body position.

Front 36

lateral geniculate nuclei

Back 36

The destination in the thalamus for most of the ganglion cell axons that form the optic nerves.

Front 37

lateral inhibition

Back 37

A process that sharpens the edges and enhances the contrast of a perceived image by inhibiting receptors lateral to those that have responded to light.

Front 38

lateral line system

Back 38

A mechanoreceptor system consisting of a series of pores and receptor units (neuromasts) along the sides of the body in fishes and aquatic amphibians; detects water movements made by the animal itself and by other moving objects.

Front 39

lens

Back 39

The structure in an eye that focuses light rays onto the retina.

Front 40

locomotion

Back 40

Active movement from place to place.

Front 41

malleus

Back 41

The first of the three middle ear bones.

Front 42

mechanoreceptor

Back 42

A sensory receptor that detects physical deformations in the body’s environment associated with pressure, touch, stretch, motion, and sound.

Front 43

middle ear

Back 43

One of three main regions of the vertebrate ear; a chamber containing three small bones (the hammer, anvil, and stirrup) that convey vibrations from the eardrum to the oval window.

Front 44

motor unit

Back 44

A single motor neuron and all the muscle fibers it controls.

Front 45

muscle spindle

Back 45

A mechanoreceptor stimulated by mechanical distortion.

Front 46

myofibril

Back 46

A fibril collectively arranged in longitudinal bundles in muscle cells (fibers); composed of thin filaments of actin and a regulatory protein and thick filaments of myosin.

Front 47

myofilaments

Back 47

The thick and thin filaments that form the myofibrils.

Front 48

myoglobin

Back 48

An oxygen-storing, pigmented protein in muscle cells.

Front 49

nociceptor

Back 49

A class of naked dendrites in the epidermis of the skin.

Front 50

olfactory receptor

Back 50

Smell receptor.

Front 51

ommatidium

Back 51

(plural, ommatidia) One of the facets of the compound eye of arthropods and some polychaete worms.

Front 52

opsin

Back 52

A membrane protein bonded to a light-absorbing pigment molecule.

Front 53

optic chiasm

Back 53

The arrangement of the nerve tracts of the eye such that the visual sensations from the left visual field of both eyes are transmitted to the right side of the brain and the sensations from the right visual field of both eyes are transmitted to the left side of the brain.

Front 54

organ of Corti

Back 54

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

Front 55

outer ear

Back 55

One of three main regions of the ear in reptiles, birds, and mammals; made up of the auditory canal and, in many birds and mammals, the pinna.

Front 56

oval window

Back 56

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 57

pain receptor

Back 57

A kind of interoreceptor that detects pain; also called a nociceptor.

Front 58

perception

Back 58

The interpretation of sensations by the brain.

Front 59

peristalsis

Back 59

(1) Rhythmic waves of contraction of smooth muscle that push food along the digestive tract. (2) A type of movement on land produced by rhythmic waves of muscle contractions passing from front to back, as in many annelids.

Front 60

photopsin

Back 60

One of a family of visual pigments in the cones of the vertebrate eye that absorb bright, colored light.

Front 61

photoreceptor

Back 61

An electromagnetic receptor that detects the radiation known as visible light.

Front 62

pitch

Back 62

A function of a sound wave’s frequency, or number of vibrations per second, expressed in hertz.

Front 63

primary visual cortex

Back 63

The destination in the occipital lobe of the cerebrum for most of the axons from the lateral geniculate nuclei.

Front 64

pupil

Back 64

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

Front 65

receptor potential

Back 65

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. The intensity of the receptor potential determines the frequency of action potentials traveling to the nervous system.

Front 66

recruitment

Back 66

The process of progressively increasing the tension of a muscle by activating more and more of the motor neurons controlling the muscle.

Front 67

retina

Back 67

The innermost layer of the vertebrate eye, containing photoreceptor cells (rods and cones) and neurons; transmits images formed by the lens to the brain via the optic nerve.

Front 68

retinal

Back 68

The light-absorbing pigment in rods and cones of the vertebrate eye.

Front 69

rhodopsin

Back 69

A visual pigment consisting of retinal and opsin. When rhodopsin absorbs light, the retinal changes shape and dissociates from the opsin, after which it is converted back to its original form.

Front 70

rod cell

Back 70

One of two kinds of photoreceptors in the vertebrate retina; sensitive to black and white and enables night vision.

Front 71

round window

Back 71

The point of contact between the stapes and the cochlea. It is where the vibrations of the stapes create a traveling series of pressure waves in the fluid of the cochlea.

Front 72

saccule

Back 72

A chamber in the vestibule behind the oval window that participates in the sense of balance.

Front 73

sarcomere

Back 73

The fundamental, repeating unit of striated muscle, delimited by the Z lines.

Front 74

sarcoplasmic reticulum (SR)

Back 74

A specialized endoplasmic reticulum that regulates the calcium concentration in the cytosol.

Front 75

sclera

Back 75

A tough, white outer layer of connective tissue that forms the globe of the vertebrate eye.

Front 76

semicircular canals

Back 76

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

Front 77

sensation

Back 77

An impulse sent to the brain from activated receptors and sensory neurons.

Front 78

sensory adaptation

Back 78

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

Front 79

sensory reception

Back 79

The detection of the energy of a stimulus by sensory cells.

Front 80

sensory receptor

Back 80

A cellular system that collects information about the physical world outside the body and inside the organism.

Front 81

sensory transduction

Back 81

The conversion of stimulus energy to a change in the membrane potential of a sensory receptor.

Front 82

single-lens eye

Back 82

The camera-like eye found in some jellies, polychaetes, spiders, and many molluscs.

Front 83

skeletal muscle (striated muscle)

Back 83

Muscle generally responsible for the voluntary movements of the body.

Front 84

sliding-filament model

Back 84

The theory explaining how muscle contracts, based on change within a sarcomere, the basic unit of muscle organization, stating that thin (actin) filaments slide across thick (myosin) filaments, shortening the sarcomere. The shortening of all sarcomeres in a myofibril shortens the entire myofibril.

Front 85

slow muscle fibers

Back 85

Muscle cells that can sustain long contractions.

Front 86

smooth muscle

Back 86

A type of muscle lacking the striations of skeletal and cardiac muscle because of the uniform distribution of myosin filaments in the cell.

Front 87

stapes

Back 87

The third of the three middle ear bones.

Front 88

statocyst

Back 88

A type of mechanoreceptor that functions in equilibrium in invertebrates through the use of statoliths, which stimulate hair cells in relation to gravity.

Front 89

statolith

Back 89

In plants, a specialized plastid that contains dense starch grains and may play a role in detecting gravity; in invertebrates, a grain or other dense granule that settles in response to gravity and is found in sensory organs that function in equilibrium.

Front 90

taste buds

Back 90

Collections of modified epithelial cells that are scattered in several areas of the tongue and mouth and are receptors for taste in humans.

Front 91

tetanus

Back 91

The maximal, sustained contraction of a skeletal muscle, caused by a very fast frequency of action potentials elicited by continual stimulation.

Front 92

thermoreceptor

Back 92

An interoreceptor stimulated by either heat or cold.

Front 93

thick filament

Back 93

A filament composed of staggered arrays of myosin molecules; a component of myofibrils in muscle fibers.

Front 94

thin filament

Back 94

The smaller of the two myofilaments consisting of two strands of actin and two strands of regulatory protein coiled around one another.

Front 95

transmission

Back 95

The conduction of impulses to the central nervous system.

Front 96

transverse (T) tubules

Back 96

Infoldings of the plasma membrane of skeletal muscle cells.

Front 97

tropomyosin

Back 97

The regulatory protein that blocks the myosin-binding sites on the actin molecules.

Front 98

troponin complex

Back 98

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

Front 99

tympanic membrane

Back 99

Another name for the eardrum.

Front 100

utricle

Back 100

A chamber behind the oval window that opens into the three semicircular canals.

Front 101

vitreous humor

Back 101

The jellylike material that fills the posterior cavity of the vertebrate eye.

Front 102

Z lines

Back 102

The borders of a sarcomere.