Chapter 29: The Senses

Question 1

Sensory Receptor Cells

Answer 1

Detect internal/external stimuli

• located in sense organs
• all nerve impulses are the same, identical

Question 2

Sensation

Answer 2

Awareness of a sensory stimulus

- results when brain integrates new info

Question 3

Perception

Answer 3

More meaningful interpretations and understanding of sensory information

• brain integrates new info w/ previous experiences
• combination of different senses

Question 4

Sensory Transduction

Answer 4

When receptor cells convert stimulus into a nerve impulse

• occurs in plasma membrane of receptor cells
• permeability changes (gated ion channels open)

Question 5

Receptor Potential

Answer 5

Electrical signal produced by sensory transduction, similar to action potential

• not an all or none effect (stronger stimulus, stronger receptor potential)
• receptor cell synapses w/ sensory neurons –> brain

Question 6

Sensory Adaptation

Answer 6

Tendency of sensory receptors to become less receptive if there’s too much stimulus
- prevents brain from reacting to normal, useless background info

Question 7

What are the five sensory receptors?

Answer 7

1) Pain Receptors
2) Thermoreceptors
3) Mechanoreceptors
4) Chemoreceptors
5) Electromagnetic Receptors

Question 8

Pain Receptors

Answer 8

Aware of injury/disease

• indicate danger to increase survival
• entire body is filled w/ these but brain

Question 9

Thermoreceptors

Answer 9

Detect heat/cold, monitor temperature of blood

• in vital organs
• hypothalamus is the body’s major thermostat

Question 10

Mechanoreceptors

Answer 10

Various forms of energy (stretch, motion, sound, pressure, etc)
- inside muscles, ears

Question 11

Chemoreceptors

Answer 11

Sensitive to chemical stimulation

• nose & tongue
• respond to chemicals dissolved in fluids
• best sense is moths

Question 12

Electromagnetic Receptors

Answer 12

Sensitive to energy of various wavelengths (magnetism, light)
- photoreceptors are most common and detect light waves from electromagnetic spectrum

Question 13

What are the three types of photoreceptors?

Answer 13

1) Eye cups
2) Compound Eyes
3) Single Lens Eyes

Question 14

Eye cups

Answer 14

Found in planar

- detect intensity/direction of light and goes away from light

Question 15

Compound Eyes

Answer 15

Many tiny light detecting units

• Ommatidia = 1 lens, 1 cornea
• Extremely acute motion detectors, excellent color vision

Question 16

Single Lens Eyes

Answer 16

Light enters thru small opening in eyes, regulated by structure (camera type eye)

Question 17

Stretch Receptor

Answer 17

a type of mechanoreceptor sensitive to changes in muscle length; detects the position of body parts

Question 18

Hair Cells

Answer 18

a type of mechanoreceptor that detects sound waves and other forms of movement in air or water (Cilia or Microvilli)

Question 19

Sclera

Answer 19

Tough white coating of eye (outermost)

Question 20

Cornea

Answer 20

Anterior, curved, clear part of sclera

- first structure to focus light

Question 21

Conjuctiva

Answer 21

Thin mucus membrane on cornea

Question 22

Choroid Coat

Answer 22

Darkly colored –> absorb light

- right w/ blood vessels

Question 23

Ciliary muscle

Answer 23

Smooth muscle, where sclera becomes cornea

- attached to lens by suspensionary ligaments to help focus light by contracting

Question 24

Lens

Answer 24

Elastic, biconvex (curves out on both sides)

- positioned behind pupil, surrounded by iris

Question 25

Iris

Answer 25

Ring of pigmented tissue, regulates size of pupil

Question 26

Aqueous Humor

Answer 26

Watery fluid between cornea and lens to provide nutrients

Question 27

Vitreous Humor

Answer 27

Jelly like fluid in chamber behind lens, helps keep shape

Question 28

Retina

Answer 28

Contains photoreceptor cells (stimulus transducers) | - rods and cons

Question 29

Rods (rhodopsin)

Answer 29

Absorb dim light --> black and white image

Question 30

Cons (photopsin)

Answer 30

Absorb bright light --> colored center

Question 31

Optic Nerve

Answer 31

Carries impulses to brain, blind spot

Question 32

Fovea

Answer 32

an eye’s center of focus and the place on the retina where the receptors are highly kind

Question 33

Blind Spot

Answer 33

the place on the retina of the vertebrate eye where the optic nerve passes through the eyeball and where there are no photoreceptor cells

Question 34

Accommodation

Answer 34

the automatic changes made by the eye as it focuses on near objects

Question 35

Visual Acuity

Answer 35

the ability of the eyes to distinguish fine detail

Question 36

Nearsightedness

Answer 36

an inability to focus on distant objects; occurs when the eyeball is longer than normal and the lens focuses distant objects in front of the retina. Also called myopia.

Question 37

Farsightedness

Answer 37

an inability to focus on close objects; occurs when the eyeball is shorter than normal and the focal point of the lens is behind the retina. Also called hyperopia

Question 38

Astigmatism

Answer 38

blurred vision caused by a misshapen lens or cornea

Question 39

What are the 3 regions of the human ear?

Answer 39

Outer ear, middle ear, inner ear

Question 40

Outer Ear

Answer 40

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

Question 41

Pinna

Answer 41

the flaplike part of the outer ear, projecting from the body surface of many birds and mammals; collects sound waves and channels them to the auditory canal

Question 42

Auditory Canal

Answer 42

part of the vertebrate outer ear that channels sound waves from the pinna or outer body surface to the eardrum

Question 43

Eardrum

Answer 43

a sheet of connective tissue separating the outer ear from the middle ear that vibrates when stimulated by sound waves and passes the waves to the middle ear

Question 44

Middle Ear

Answer 44

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

Question 45

Oval Window

Answer 45

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

Question 46

Eustachian tube

Answer 46

an air passage between the middle ear and throat of vertebrates, that equalizes air pressure on either side of the eardrum

Question 47

Inner Ear

Answer 47

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

Question 48

Cochlea

Answer 48

a coiled tube in the inner ear of birds and mammals that contains the hearing organ, the organ of Corti

Question 49

Organ of Corti

Answer 49

the hearing organ in birds and mammals, located within the cochlea

Question 50

Semicircular Canals

Answer 50

fluid filled channels in the inner ear that detect changes in the head’s rate of rotation or angular movement

Question 51

Utricle

Answer 51

a fluid-filled inner ear chamber containing hair cells that detect the position of the head relative to gravity

Question 52

Sccule

Answer 52

a fluid filled inner ear chamber containing hair cells that detect the position of the head relative to gravity