IP Teaching Resources

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A. How to use this laboratory workbook.

Each topic section contains blanks that require filling in from the discussion or lecture material presented during the week. Definitions of terms that are applicable to the organ system or concept under study can be obtained from lecture material or the textbook. One or more figures or graphs will be provided that require labeling. In most cases blank lines are provided as prompts for the labels with lines or arrows indicating the object to be labeled.

We suggest using pencil when making initial notations and labeling in the body of the Workbook. Corrections can be entered using ink after the workbook has been examined by the TA or instructor for accuracy.

B. Grading.

The lab book will be handed in on Mondays for examination and grading by the TA. The lab notebook will be returned before the start of the next laboratory and demonstration session on the subsequent Friday.

The credit you receive will from the demonstration/discussion section will be based on the accuracy of the entries in this workbook and the answers to the questions given under each topic. The Teaching Assistant will announce a final or lab practical for the demonstration/laboratory part of the course.

C. Safety.

Good laboratory practice should be in effect at all times. Often this amounts to a healthy dose of common sense. If you are mixing chemicals other than salts, always use eye protection, and an apron. If the chemicals are volatile, always use a hood. If you are heating a solution to dissolve a chemical, always use a hood, and be sure that the heating apparatus in fully inside the hood, so that fumes are vented up the exhaust pipe of the hood. Ensure that the hood airflow fans are on and working before beginning. The front outside corner of the hood may have a mark indicating where the door must be positioned for proper airflow.

If you are to use an open flame, make sure the area around the burner is clear of combustibles and flammable objects. Never bring lab books or papers near such an area. Try not to place books or note pads inside a hood or near solutions being heated on a lab bench because spilled solutions can ruin notebooks. Always read instructions of a procedure before beginning, so that you know exactly what to expect and can anticipate any reagents needed. Being thoroughly familiar with a procedure also means you will not need to have an instruction book handy and therefore in harms way.

Microscopes. Some demonstrations require microscopes and lamps. The microscope should always be carried by the neck, not the base nor the eye pieces. Never touch the lenses, except to clean with proper cleaning paper or cloth. Never use ordinary paper of wipe lens because they will be scratched. Do not remove eyepieces from microscopes nor attempt to interchange them unless specifically instructed to do so. Always return the microscope and lamp to the same bin or cubical it was originally checked out from. If you check out a microscope, take responsibility for returning it. If someone who is not a partner asks to use your microscope, ask them to replace your name on the checkout sheet with theirs.

The student who checks out a microscope, or any equipment, is responsible for it. Report any damage immediately to the TA or instructor. Report any malfunction immediately. Never return non-functioning equipment to its storage place. Instead, it should be marked for repair, or attention and left with the TA or instructor, after your name is removed as the assigned recipient.

Dissecting equipment. Very fine forceps or microscissors will be used for some dissections. Fine watchmakers forceps are always kept in a plastic sheath. The sheath should never be removed unless the forceps are actually in use. Never lay a pair of fine forceps down on the table unless they are first covered by the sheath provided. With the sheath on, a pair of fine forceps are unlikely to be damaged when dropped on the floor or table.

Never, ever touch the bare tips of the forceps to the table top or to a hard object. The tips are very finely machined so that they come together as two flat surfaces. These surfaces are needed to grasp extremely fine tissues or nerves. Even the slightest touch will ruin this alignment, and render the forceps useless. The difference can only be appreciated when the forceps are being used or viewed under the dissecting microscope.

Microscissors are much more robust than watchmakers forceps, and while they are difficult to damage even when dropped on the floor, use the same care with microscissors that you learn to take with fine forceps. Always put microscissors in their holders when not in use. Always cover the cutting tips when not in use.

Chemicals. Few or no corrosive materials will be used. If they are, they should always be used in a hood. Keep the tops of all chemical containers covered, whether the contents are solids or solutions. Only remove the tops to prepare solutions. All chemical containers must be properly labeled, even reagent bottles made up for temporary use. If they are not, or if a label comes off during use, bring it to the attention of the instructor. Always write down chemicals used in your workbook for a permanent record. List every ingredient, so that the same solutions may be made up at a future date. Be sure to note any special precautions, such as when ingredients must be mixed in a certain order during preparation.

Few of no solvents will be used, flammable or otherwise. If they are, they must be used only in a hood, and by properly trained personnel. If you are not familiar with a chemical, ask the TA or instructor about care in using it.

Always return chemical bottles or flasks to their proper place on a shelf, in a hood or in a refrigerator, unless otherwise instructed. If plastic, glass or cork tops are corroded, broken or otherwise damages, bring it to the attention of the TA or instructor immediately.

Saline solutions used for maintaining freshly dissected tissues or organs, should be considered to be corrosive. When finished with wax dissection dishes, always clean them by first running tap water from the sink over the wax dish to remove all salts (the amount washed into the drain will not damage sewer pipes). Then remove the pins and tissues. Drop the remaining tissues into the trash, or into a container provided unless otherwise instructed. Daub both the wax dish and the pins dry with tissue paper and return them to their proper containers. The pins are usually made of steel and will rust if not dried properly. Sometimes dissections dishes are stored with the pins left in place in the wax as a matter of convenience and to help keep track of the pins.

Dissecting pins. There are two main types of dissecting pins, large and small, both usually made of steel, even if they appear black. The largest pins always have a head made of bronze-colored material meant for pushing the pin into a substrate, and the other end pointed. The other main type of pin useful with very small tissues are the minuten Nadeln (German for needle), or simply minutens. These have no head, are very small and short and easy to overlook or lose. Because they are the size of a sliver, they are also very easy to accidentally jab into your fingers if you try to hold them.

Therefore, the most convenient way to handle minutens is by grasping them in the middle with undamaged watchmakers forceps. If the forceps are at all damaged or the jaws not parallel, they do not grip the minutens well at all which is yet another reason why great care must be used to prevent damage to the tips of the forceps.

Some forceps are slightly magnetized and when brought near the minutens tend to attract them in clumps. When this happens, it might be most convenient to manipulate the minutens one at a time, or with two forceps. Pin the minutens or ordinary dissecting pins into the wax of a dissecting dish before starting dissections. This way the pins will all be ready when they are needed, but out of the way.

Scales. Balances to weigh chemicals are to be covered when not in use. Top loading balances are provided with proper disposable weighing containers to weigh either liquid or solid. First tare the container with the weighing boat on the balance, then pour or spoon in the chemical or solution until the proper weight is attained. It is always more convenient to ladle solid powders or crystals from a second flat container, such as an extra weighing boat, not the original bottle or storage flask, and return an unused amount to the original container when finished.

Electrical appliances. Equipment with electric cords should be plugged into properly grounded electrical outlets only. The cords should be out of the way and if possible not draped on the floor, nor across the tops of tables in reach. Any fraying cords that are noticed should be brought to the attention of the instructor or TA immediately, and be treated as unsafe. When unplugging a cord from an electrical outlet, always pull the connector out of the socket by the plug, never by the cord. When plugging a piece of electrical equipment into an outlet, it is always best to check first to be sure that the instrument is turned off when the cord is plugged in.

Never replace a fuse in a piece of equipment with a piece of aluminum foil because a fuse is blown and no replacement is available. Never operate electrical equipment when there is water on the floor or the floor is wet. If you are unsure about how of piece of lab equipment operates, ask the TA, or instructor.

Battery operated equipment should always to left off when not in use, and only to turned on to make a measurement. During dissections or recordings. It is best to turn battery operated equipment off in between measurements. Batteries or often stored in refrigerators to help extend their life. When replacing batteries, always check to see if they are cold to the touch by holding them in you hand. If they are cold, warm, them to room temperature by holding them in your hand for a while before installing them. Cold dry cell batteries that are placed under a load have been known to explode on occasion.

A piece equipment that is battery operated should never be stored with the batteries in place. It is always a good idea to start of new class with fresh batteries. Always suspect a dry cell battery that has been left in its holder out of sight to have leaked during storage. While this is common in flashlights, it can be a disaster is a piece of sensitive electronic equipment that uses large dry cell batteries.

It is best to store dry cell batteries in individual plastic containers in a cool or cold place in such a manner that it is impossible for current to flow from the anode to cathode. Never store more that two batteries loosely in the same container at the same time.

Brush recorders. Gould recorders that write with thick ink under pressure are preferred by physiologist because of their superior pen response speed. These recorders require that the pen tip be flat against the special recording paper and under pressure so that the ink does not escape. When used with transducers, the proper procedure to turn on the Brush recorder is to first ensure that the recorder is plugged in and the pilot lamp with the recording pens in standby and the drive motor off. Then the transducer is connected to the tissue to be recorded, and connected to the Brush recorder. When the transducer appears to be functioning, select the largest voltage range on the Brush recorder and a slow pen speed and turn on the drive motors by pushing one of the buttons along the top of the Brush recorder.

With the recorder paper moving at a slow speed and the pen in the middle of the recording range (center on the paper) turn the voltage range to more sensitive values until the recorder pen moves by the expected travel. Select a final range so that the recorder pen stays well within the edges of its travel on the recorder chart. Now increase the recorder speed until the measurement is seen to be ideal.

If the events being recorded are fast, only leave the pen recorder on for short periods of time. If the events are slow, the pen recorder may be left on for a longer times, but use some judgment and never walk away and leave the recorder on. Some experiments or demonstrations require a piece of recorder paper be attached to the workbook. Because of this get into the habit of constantly noting the voltage range and recorder speed on the recorder paper. This is best done with a ball point pen because the Brush recorder paper is specially treated to accept ball point pen ink, which is the ink used in the recorder cartridges.

D. Signature block.

_____________________________________ ____________________

(Student's signature, written and printed) (TA’s initials and date)

Sign the blank spaces as indicated above to show that you have read and understood the cautionary warns in the section on Safety.

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