HUMAN ANATOMY /PHYSIOLOGY · PDF fileHUMAN ANATOMY /PHYSIOLOGY LAB #1 - CHEEK CELL LAB INSTRUCTIONS FOR LAB REPORTS Your lab reports must be completed using the format outlined below

HUMAN ANATOMY /PHYSIOLOGY

LAB #1 - CHEEK CELL LAB

INSTRUCTIONS FOR LAB REPORTS

Your lab reports must be completed using the format outlined below. If any section or

information is missing, points will be taken off. You are required to turn in one lab report per group.

Make sure everyone in your group is aware of what their responsibilities are (it is highly

recommended that you exchange phone numbers).

Complete your lab report using the following format:

(1) PROBLEM: How do different stains (water, iodine, methylene blue) affect the visibility ofepithelial cells under the microscope?

(2) HYPOTHESIS: [YOU NEED TO PROVIDE AN EDUCATED GUESS HERE. Since cells aretransparent in nature, and cannot be seen under the microscope without a stain,provide an educated guess as to which stain you think will allow you to see yourcheek cells best. Ex: We hypothesize that iodine will stain our cheek cells bestbecause .... etc.]

(3) MA TERJALS: [List the materials you used during the lab. A list is provided in the "2-3,Observing A Human Cell" Lab Packet. Can you think of anything you used thatis not on this list? If so, add it to the list in your report.]

(4) PROCEDURE: [You must copy the procedure down in your report. You can copy it straight fromthe "2-3, Observing A Human Cell" Lab Packet, or put it in your own words.Make sure it is detailed, and lists "step-by-step" what you did.]

(5) RESULTS: [First of all, include your 3 DRAWINGS of the cheek cells under the different stains(water, iodine, methylene blue) here. Secondly, answer questions 1-3 froln the "2-3,Observing A Human Cell" Lab Packet in this section. Make sure you answer thesequestions in COMPLETE SENTENCES!]

(6) DISCUSSION: [Here you should address the major findings of the RESULTS. Also, you need toanswer questions 4-6 from the "2-3, Observing A Human Cell" Lab Packet inthis section. Make sure you answer these questions in COMPLETESENTENCES!

(7) CONCLUSION: [Summarize your results. Explain whether your hypothesis was correct orincorrect. If your hypothesis was partially correct, explain what was missing.Finally, tell me what you learned.]

"The Cheek Cell" LAB REPORT

HUMAN ANATOMYIPHYSJOLOGY

GRADING FORM (50 POINTS)

TOPICS CRITERIA POINTS(5=E:s:cellent; 4=Good;3=Fair; 2=Difficulties;l=Poor; O=Incomplete)

Section 1: PROBLEM Was the problem clearly stated?Was everything spelled correctly?Was the problem posed as a question?

-Section 2: HYPOTHESIS Did the hypothesis directly address the problem (whichstain is predicted to be best)?Did the hypothesis provide a logical explanation for theproblem?Did the writer provide an explanation for theirhypothesis (why they thought that stain would be best)?

Section 3: MATERIALS Were all the materials used in the experiment listed?Did the writer include extra materials that Were not onthe original list (ex: pencil, paper, textbook, etc)?

.. -Section 4: PROCEDURE Were all the steps taken in the experiment listed?

Were any steps left out?Was there enough detail in the procedure?

Section 5: RESULTS Were questions 1-3 from the lab packet answered here?Were the questions answered in complete sentences?Was enough detail provided in the answers?Were the drawings of the cheek cells in the differentstains provided here? Were the drawings titled? Werethe drawings labeled? - .._.

Section 6: DISCUSSION Were questions 4-6 from the lab packet answered here?Were the questions answered in complete sentences?Was enough detail provided in the answers?

Section 7: CONCLUSION Were the major-findings of the experiment summarized?Did the writer address their hypothesis (whether it wassupported by the results or not)?Did the writer state what they learned from theexperiment? (Saying that you didn't learn anythingdoesn't count here!)

WERE ALL 7 SECTIONS Were there any sections missing?OF THE LAB REPORT Were the sections presented in order?INCLUDED? Was there information presented in a section that should(Organization) have been presented in a different section?Spelling ,Grammar, and Were multiple spelling and grammatical errors made?Clarity Should the writer use a dictionary/spellcheck in the

future?Does the writer need to proofread his/her work? IDid the writer provide enough description for the readerin each step?Was the process easy to follow? I

Overall Effect and Was it apparent that the writer put effort into their work? I

Impression on the Reader Was the report's presentation aesthetically pleasing?

OVERALL GRADE (50 POINTS MAXIMUM) SCORE =

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THE COMPOUND MICROSCOPE

One of the most essential tools in the study of biology isthe microscope. With the help of different types ofmicroscopes, biologists have developed detailed con-cepts of cell structure and function. The type of micro-scope used in most biology classes is the compoundmicroscope. It contains a combination ofIenses and canmagnify objects normally unseen with the unaided eye.

The eyepiece lens is located in the top portion ofthe microscope. This lens usually has a magnification of10 X. A compound microscope usually has two otherinterchangeable lenses. These lenses, called objectivelenses, are at the bottom of the body tube on therevolving nosepiece. By revolving the nosepiece, eitherof the objectives can be brought into direct line with thebody of the tube. .

The shorter objective is Oflow power in its magni-fication, usually 10 X. The longer one is of high power,usually 40X or 43 X.The magnification is always markedon the objective. To determine the total magnification ofa microscope, multiply the magnifying power of theeyepiece by the magnifying power of the objective beingused. For example, the eyepiece magnifying power, lOX,multiplied by the low-power objective, lOX, equals100 X. The total magnification is 100 X. .

A microscope also produces clear contrasts toenable the viewer to distinguish between objects thatlie very close together. Under a microscope the detail ofobjects is very sharp. The ability of a microscope to

produce contrast and detail is called resolution, orresolving power. Although microscopes can have the.same magnifying power, they can differ in resolvingpower.

Learning the name, function, and location of each ofthe microscope's parts is necessary for proper use. Usethe following procedures when working with the micro- .scope.

1. Remove the microscope from its storage area byplacing one hand beneath the base and grasping thearm of the microscope with the other hand.

2. Gently place the microscope on the lab table withthe arm facing you: The microscope's base shouldbe .resting evenly on the table, approximately 10centimeters from the table's edge.

3. Raise the body tube by turning the coarse adjust-ment knob until the objective lens is about 2 centi-meters above the opening of the stage.

4. Revolve the nosepiece so that the low-power objec-tive (10 X) is directly in line with the body tube. Aclick indicates that the lens is in line with the open-ing of the stage.

5. Look through the eyepiece and switch on the lampor adjust the mirror so that a circle of light cari beseen. This is thefield ofview. Moving the lever of thediaphragm permits a greater or smaller amount oflight to come through the opening of the stage.

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6. Place a prepared slide on the stage. Place the spec-imen over the center of the opening of the stage.Fasten the stage clips to hold the slide in position.

7. Lookatthe microscope from the side. Carefully turnthe coarse adjustment knob to lower the body tubeuntil the low-power objective almost touches theslide or until the body tube can no longer be moved.Do not allow the objective to touch the slide.

S. Look through the eyepiece and observe the speci-men. Ifthe field ofview is out of focus, use the coarseadjustment knob to raise the body tube while look-ing through the eyepiece. When the specimencomes into view, use the fine adjustment knob tofocus the specimen. Be sure to keep both eyes open

when viewing a specimen. This helps prevent eye-strain.

9. Adjust the lever of the diaphragm to allow the rightamount of light to enter.

10. To view the specimen under high power (43 X),revolve the nosepiece until the high-power objec-tive is in line with the body tube and clicks intoplace.

1L Look through the eyepiece and use the fine adjust-ment knob to bring the specimen into focus.

12. After every use remove the slide. Clean the stage ofthe microscope and the lenses with lens paper. Donot use other types of paper to clean the lenses, asthey may scratch the lenses.

PREPARING A WET·MOUNT SLIDE

L Obtain a clean microscope slide and a coverslip. Acoverslip is very thin, permitting the objective lensto be lowered very close to the specimen.

2. Place the specimen in the middle of the microscopeslide. The specimen must be thin enough for light topass through it.

3. Using a medicine dropper, place a drop of water onthe specimen.

4. Lower one edge of the coverslip so that it touchesthe side of the drop of water at a 45° angle. The water

.will spread evenly along the edge of the coverslip.Using a dissecting needle or probe, slowly lower thecoverslip over the specimen and water. Try not totrap any air bubbles under the coverslip. Air bubblesinterfere with the view ofthe specimen. Ifair bubblesare present, gently tap the surface of the coverslipover the air bubble with a pencil eraser.

5. Remove any excess water at the edge of the coverslipwith a paper towel. If the specimen begins to dryout, add a drop of water at the edge of the coverslip.'

STAINING TECHNIQUES

L Obtain a clean microscope slide and coverslip.2. Place the specimen in the middle of the microscope

slide.3. Using a medicine dropper, place a drop of water on

the specimen.4. Place one edge of the coverslip so that it touches the

side of the drop of water at a 45° angle. After thewater spreads along the edge of the coverslip, use adissecting needle or probe to lower the coverslipover the specimen.

5. Add a drop of stain at the edge of the coverslip.Using forceps, touch a small piece of lens paper orpaper towel to the opposite edge of the coverslip.The paper causes the stain to be drawn under thecoverslip and stain the cells. Some common stainsare methylerie blue, iodine, fuchsin, and Wright's.

N~Ine _ Date ~ _

2-3. OBSERVING A HUMAN CEll

Instructions: (1.) Read the text and complete the project. (2.) Use the text to helpyou to complete the investigation and answer the questions.

Step 1 Step 3

All living things are made of cells; scientists call cells the "building blocks oflife."Your skin, muscles, skeleton, blood, internal organs, and all other parts of your bodyare built of trillions of cells.

Many of the cells ofyour body cannot be seen without the use of a microscope andspecial stains. While completing this investigation, you will use a microscope to ob-serve a few of the epithelial cells that line your mouth. You will use stains to makethese cells more visible.

Obtain the following materials:

o small container of watero microscope slideo cover slip

o three toothpicksM4T~g..lflLS 0 iodine (stain)

o methylene blue (stain)o eye dropper

Special Precaution: You will use three different toothpicks to scrape (GENTLY)the lining of your mouth. After using a toothpick, IMMEDIATELY place it in thetrash.

To complete this investigation- .

1. Gently scrape the inside lining of your cheek with a toothpick.

2. Place two drops of water on a clean microscope slide.

-2-3. OBSERVING A HUMAN CELL, continued

D 3. With a toothpick, mix the cheek cells with the water on the slide.

D 4. THROW AWAYTHE TOOTHPICK.

o 5. Place a cover slip over the mixture and place the slide on your microscope; focusto high power.

D 6. In Circle A, sketch what you see through your microscope.

o 7. With a new toothpick, gently scrape the lining of your cheek again.

D 8. Place two drops of iodine on a clean microscope slide; repeat steps 3, 4, and 5,this time with the iodine. In Circle B, sketch what you see.

D 9. With a new toothpick, repeat these steps-this time using methylene blue asyour stain. In Circle C, sketch what you see.

A B

evel One Questions:

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1. Did you have any difficulty in seeing the epithelial cells and sketching them in cir-cle A? Explain.

2. In what way did the cells stained with iodine look different? Explain.

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In what way did the cells stained with methylene blue look different? Explain.

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4. Why was it so essential for you to throwaway the toothpick? (You are likely to thinkof a health risk that has been in the news in recent years. In addition to that, whatother health risks might be avoided by such precautions?)

5. Describe the general shape of the epithelial cells.

6. What organelle(s) within the cell did you recognize?

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