Sensory System

Question 1

What are different ways that the senses can be classified into types?

Answer 1

-General senses or special senses or; -Encapsulated or unencapsulated.

Question 2

Where is a sensation actually perceived?

Answer 2

Brain

Question 3

What is the function of proprioceptor?

Answer 3

PROVIDE INFORMATION ON POSITION and MOVEMENT of BODY PARTS as well as the length and the extent of contraction and tension in our muscles.

Question 4

What is two-point discrimination?

Answer 4

The ability to distinguish one touch stimulus from two is called two-point discrimination.

Neurological test - involves simultaneously touching two points over one area to determine whether the ability to feel the two separate stimuli is present.

Question 5

What are the three layers of the eyeball?

Answer 5

Sclera, choroid, and retina

Question 6

What is the function of melanin in the choroid?

Answer 6

the choroid contains large amount of the dark pigment melanin.
This almost-black layer helps PREVENTS SCATTERING OF INCOMING LIGHT RAYS, which could make it hard for the eye to focus on an image.

Question 7

What involuntary muscle structure changes the size of the pupil?

Answer 7

Iris

Question 8

What involuntary muscle structure focuses the lens on close objects?

Answer 8

Ciliary muscle

Question 9

What are the humors of the eye?

Answer 9

Aqueous: Watery fluid in front of the lens
Vitreous: Jellylike fluid behind the lens

Question 10

How are rods and cones used in vision?

Answer 10

Rods are the receptors for night vision, and cones are the receptors for daytime vision.

Question 11

What is the function of the ganglion cells of the retina?

Answer 11

Information from ganglion cells helps the body DETERMINE whether it is DAY or NIGHT, as well as the LEVEL OF MOONLIGHT (monthly phases). This helps our body’s internal clock mechanisms synchronize themselves to the daily, monthly, and seasonal rhythms of our external environment.

Question 12

What senses are detected in the ear?

Answer 12

Hearing, equilibrium, and balance

Question 13

Describe the three main parts of the ear?

Answer 13

• External ear (auricle and external auditory canal);
• Middle ear (contains the malleus, incus, and stapes);
• Inner ear (bony labyrinth filled with fluid; divided into the vestibule, semicircular canals, and cochlea)

Question 14

What ear structure vibrates when sound waves travel through the acoustic canal?

Answer 14

Tympanic membrane

Question 15

How do the ossicles work in helping a person to hear?

Answer 15

Sound waves cause eardrum vibration, which is transmitted and AMPLIFIED by the ear ossicles as it passes through the middle ear.

Question 16

Where are the receptor cells for hearing located?

Answer 16

Hair cells in the organ of Corti

Question 17

Where are the receptor cells for equilibrium located?

Answer 17

The vestibule and the three semicircular canals.

Question 18

What is the difference between static equilibrium and dynamic equilibrium?

Answer 18

** Static equilibrium is a signal that is interpreted by our brain as our “SENSE OF GRAVITY.”

**Dynamic equilibrium is the result of a nerve impulse that is generated by the crista ampullaris when the speed or direction of movement of your head changes. This “SENSE OF MOTION” is called dynamic equilibrium.

Question 19

Where are taste receptors located?

Answer 19

Tongue

Question 20

Identify the primary tastes that humans can perceive.

Answer 20

Sweet, sour, bitter, salty;
also metallic, meaty (called umami)

Question 21

Where are olfactory receptors located?

Answer 21

Epithelial tissue of the upper part of the nasal cavity

Question 22

Why are odors that are very noticeable at first not sensed at all after a short time?

Answer 22

Because of adaptation, a decrease in receptor sensitivity over time

Question 23

Why do smell sensations trigger memories and emotions?

Answer 23

Because olfactory pathways are closely associated with the limbic system of the brain

Question 24

In what organ are all the senses experienced?

Answer 24

Brain

Question 25

Name the general senses found in the skin or subcutaneous tissue and list the type of stimuli to which each of them responds. Identify which of these general senses are unencapsulated.

Answer 25

All are Encapsulated specialized receptors that respond to pain, touch, tickle, and temperature; (1) TACTILE (Meissner corpuscles) - close to skin surface (fingertips and lips) - detect light touch and vibration; (2) BULBOUS (Ruffini corpuscles) - subcutaneous tissue of fingers and dermis - detect touch and pressure; (3) LAMELLAR (Pacini corpuscles) - found deep in the dermis (subcutaneous tissue around joints, mammy glands and genitals) - detect pressure and vibration (4) BULBOID (Krause corpuscles) - dermis and subcutaneous tissue (mucosa of lips, eyelids and genitals) - detect touch and cold

Question 26

Name the two types of proprioceptors and give the location and general sense of each.

Answer 26

Golgi Tendon Receptor - junction of muscles and tendons - sense the contraction and extension of tendons (sense muscle tension) Muscle Spindle - skeletal muscles - sense change in muscle length

Question 27

Explain how the iris changes the size of the pupil.

Answer 27

It contains two types of muscle fibers - iris dilator and iris sphincter muscles The iris dilator muscle opens your pupil from the inside out The iris sphincter is a circular muscle that controls closing your pupil

Question 28

Explain how the ciliary muscle allows the eye to focus on near and far objects.

Answer 28

Muscle fibres in the ciliary body help the eye to focus on near or far objects by changing the shape of the lens

Question 29

Define presbyopia, and describe the common cause of this condition.

Answer 29

is a refractive error that occurs when the lens of the eye loses its elasticity and becomes less flexible over time - Makes it difficult to see things close-up - occurs with aging

Question 30

Name the two types of photoreceptor cells in the retina. Explain the difference between them.

Answer 30

RODS work in the dark CONES work in daylight

Question 31

Define glaucoma, and describe its cause.

Answer 31

A chronic eye disease that occurs when the optic nerve is damaged Due to increased pressure in the eye

Question 32

Describe cataracts, how they are caused, and what can be done to prevent them.

Answer 32

- Clouding of the eye's lens that can cause blurry or hazy vision - Caused by ultraviolet light from the sun - Wear sunglasses

Question 33

Explain the difference between the fovea centralis and the blind spot.

Answer 33

Fovea Centralis provides the sharpest vision Blind Spot is an area that lacks vision

Question 34

Briefly describe the structure of the external ear.

Answer 34

Auricle (PINNA) - collect sound waves, focus into acoustic canal External Acoustic canal - contains ceruminous glands Ends at tympanic membrane (eardrum)

Question 35

Explain how sound waves are transmitted through the middle ear.

Answer 35

Enter external ear through canal Tympanic membrane to vibrate, causing malleus, incus and stapes to vibrate against oval window causing fluid to Sound waves strike the TYMPANIC MEMBRANE (eardrum) to vibrate, that movement is transmitted and amplified by the ear OSSICLES as it passes through the MIDDLE ear. Movement of the STAPES against the oval window causes movement of fluid in the INNER ear.

Question 36

Describe how sound waves are converted to an auditory impulse.

Answer 36

SOUND WAVES enter the ear canal and cause the eardrum to vibrate. VIBRATIONS pass through 3 connected bones in the middle ear. This motion SETS FLUID MOVING in the inner ear. Moving fluid bends thousands of delicate hair-like cells, which convert the vibrations into NERVE IMPULSES

Question 37

Explain how the structures of the inner ear help maintain balance or equilibrium.

Answer 37

Mechanoreceptors for equilibrium are located in the canals of the inner ear. These canals in the inner ear contain fluid and fine, hairlike sensors that help keep balance.

Question 38

Identify where the gustatory cells are located, and name the “primary” tastes to which they respond.

Answer 38

On our tongue. Primary tastes are sweet, sour, bitter, salty, metallic, and umami (meaty).

Question 39

Explain how the sense of smell is stimulated.

Answer 39

Olfactory Receptors are stimulated by odor-causing chemicals That nerve impulse travels through the olfactory neurons in the olfactory bulb and cranial nerve 1 It then enters the thalamic and olfactory centers of the brain, Where the nervous impulses are interpreted as specific odors

Question 40

16. Explain why food loses some of its taste when you have a bad cold with a stuffy nose.

Question 41

17. Explain why the longer you are in a newly painted room, the less able you are to smell the paint.

Question 42

18. Explain the visual pathway including where in the eye is light sensed and where is it perceived. (Be specific.)

Question 43

19. Explain why the smell of a “doctor’s office” or the smell of a turkey cooking on Thanksgiving can easily generate an emotional response.