Lab 6 Senses

Materials

Organisms

Fresh carrot

Fresh apple (22 cm x 28 cm x 8 cm)

Pictures from textbook

Human eye

Human ear

Human skin

Chemicals

5% sucrose (about 1 tablespoon of sugar in one cup of water)

10 % NaCI (sodium chloride) (about 1 tablespoon of table salt in 1/2 cup of water)

0.5% acetic acid (household vinegar is OK)

Hardware

Construction paper for afterimage cards

Penlight (or desk lamp)

Paper tube (3 cm x 45 cm)

Meter stick (yardstick will work)

Tuning fork (or two spoons)

Scissors

Millimeter ruler

3 medium size bowls

Ice bath

Cotton swabs

Learning Objectives Students should be able to

1. identify the parts of the eye, ear, and skin and state a function for each part;

2. describe the experiments that make up this laboratory session and explain their significance.

Introduction

Sense organs contain receptors which are sensitive to a particular type of environmental stimuli. After

receptors receive stimuli, they generate nerve impulses. Eventually these nerve impulses reach the brain,

where the phenomenon sensation occurs. The brain interprets the world around us and depends on the

receptors for the proper input. Because the sense organs have a limited ability to respond to the

environment, we can be fooled sometimes. Human Eye

The human eye is a special sense organ because it is a large, complex organ containing many receptors.

The receptors in the eye are either rods or cones, both of which are photoreceptors. The parts of the eye

are depicted in Figure 18.6 on page 345 of your textbook.

With the help of figure 18.6, identify the following structures and give a function for each structure in

the space provided.

Sclera

Cornea

Choroid

Retina

Fovea centralis

Lens

Ciliary body

Iris

Pupil

Optic nerve Which of the structures listed aid in refracting and focusing light rays?

Which of these structures contain( s) the receptors for sight?

What are the receptors for sight?

Which of the structures listed transmit(s) nerve impulses to the brain?

Afterimages

We see images because the rods and cones are generating nerve impulses for transmission to the brain.

Occasionally the brain retains an image even after the impulses have stopped. These images are called

afterimages. A positive afterimage is one in which the bright parts of the object remain bright and the

dark parts remain dark. In a negative afterimage the bright parts of the object appear dark and the dark

parts appear bright.

Experimental Procedure:

Center a red card on a black sheet of paper and stare intently at the card. After about thirty seconds or

longer and without shifting the eyes, place a white sheet of paper over the red card. Describe in the

following table the color of the image that "appears" on the white paper.

Repeat by placing green, blue, and yellow cards on the black paper and later covering with a white sheet.

Card Color Color of Afterimage Red

Blue

Yellow

Green

Blind Spot

The blind spot occurs where the optic nerves exit the retina. No vision is possible 

SuperTutor

(15)

Status NEW Posted 09 Jun 2017 07:06 AM My Price 15.00

-----------

Attachments

file 1496993524-Solutions file.docx preview (51 words )

S-----------olu-----------tio-----------ns -----------fil-----------e -----------Hel-----------lo -----------Sir-----------/Ma-----------dam----------- T-----------han-----------k y-----------ou -----------for----------- yo-----------ur -----------int-----------ere-----------st -----------and----------- bu-----------yin-----------g m-----------y p-----------ost-----------ed -----------sol-----------uti-----------on.----------- Pl-----------eas-----------e p-----------ing----------- me----------- on----------- ch-----------at -----------I a-----------m o-----------nli-----------ne -----------or -----------inb-----------ox -----------me -----------a m-----------ess-----------age----------- I -----------wil-----------l b-----------e q-----------uic-----------kly----------- on-----------lin-----------e a-----------nd -----------giv-----------e y-----------ou -----------exa-----------ct -----------fil-----------e a-----------nd -----------the----------- sa-----------me -----------fil-----------e i-----------s a-----------lso----------- se-----------nt -----------to -----------you-----------r e-----------mai-----------l t-----------hat----------- is----------- re-----------gis-----------ter-----------ed -----------onÂ----------- th-----------is -----------web-----------sit-----------e -----------Tha-----------nk -----------you----------- -----------

Not Rated(0)

• Buy Answer