Endocrine Lab Report Sample

Endocrine Lab Report Paper Smooth muscles are typically under control of the autonomic nervous system, and do not contract voluntarily. Smooth muscle contracts slowly, and does not exhibit the characteristic twitch seen in skeletal muscle. In addition, smooth muscle is not prone to muscle fatigue, making it an ideal component of sphincter muscles. Smooth muscle is found in the gastrointestinal tract of many animals, and is responsible for peristaltic movements. Smooth muscle is also present in the walls of arteries and arterioles, where it helps to regulate blood pressure and flow. Smooth muscle contractions are affected by calcium and potassium ions. Calcium ion influx into the smooth muscle cell initiates a contraction. Potassium ion concentration in the extracurricular medium affects the resting membrane potential of the cell, bringing it closer to or farther away from its threshold voltage. Neurotransmitters affect different types of smooth muscle differently, depending on the association of the smooth muscle with excitable cells. In general, acetylenes increases the muscle cells permeability to calcium, while epinephrine decreases the cells permeability to calcium. The earthworm (Limericks SSP. ) gut can be dissected and examined in vitro sing an organ bath and force transducer. This preparation is robust; it can remain active for several hours. In this experiment, you will measure the rate and force of contractions in the in vitro earthworm gut, and examine its response to changes in extracurricular ion concentration and to the presence of neurotransmitters. Required Equipment A computer system powerful 12TH Chart 5. 0 or later Bridge Pod Force Transducer Ring stand with micrometeorites and clamps Organ Bath 250 ml beaker Dissection tools: Glass finger bowl 15% Ethanol Sharp scissors Blunt probe Dissection tray with wax or pad Dissection pins Eyedropper We will write a custom essay sample on Endocrine Lab Report specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Endocrine Lab Report specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Endocrine Lab Report specifically for you FOR ONLY $16.38 $13.9/page Hire Writer Earthworm saline solution of the following types: Normal saline (room temperature) Cold saline (5-ICC) Warm saline (ICC) High Ca+ High K+ Ca+-free Acetylenes Epinephrine Procedures A. Set up and calibration of equipment 1 . Securely mount the organ bath, micrometeorites, and force transducer to the ring stand. The force transducer should be mounted so that it is over the opening of the organ chamber. Close the drain valve on the bottom of the organ bath. 2. Turn on the Powerful and make sure the USB cable is connected to your computer. 3. Make sure the Bridge Pod is connected to the Pod Port on Input 1 of the Powerful. 4. Connect the force transducer cable to the back of the Bridge Pod. 5. Launch Chart and open the settings file for this experiment EWE Gut Settings. 6. A new blank data file will open after a few moments. This file should have one channel, labeled Force. 7. Click the Force channel function pop-up menu and select Bridge Pod. The Bridge Pod dialog box will open. 8. Observe the signal in the dialog box. Zero this signal by turning the knob on the front of the Bridge Pod (figure). If you cannot zero the Bridge Pod, contact your instructor for assistance. B. Earthworm dissection Refer to the diagrams in your earthworm dissection guide for assistance. Anesthetizing 1. Fill a fingernail halfway with 15% ethanol. 2. Obtain a large earthworm and rinse it under tap water to remove excess dirt. 3. Place the earthworm in the fingernail for five minutes; the earthworm should stop moving. Dissection: exposing the gut 1 . Remove the earthworm from the ethanol and place it on a dissection tray. 2. Pin the earthworm to the tray using one pin on either end of the worm. 3. Moisten the earthworm with room temperature earthworm saline. You must keep the worm moist at all times during the dissection. Locate the cellulite (copulation organ); this structure is closest to the anterior of the earthworm. 5. Using fine pointed scissors, carefully make a shallow incision in the cellulite. Make this incision to the side of the midlines; this techniques will prevent you from cutting into the gut. NOTE: It is essential not to cut deeply during the dissection; you will damage the gut t issue. If you tear the gut, obtain another earthworm and start over. 6. Continue cutting the skin of the earthworm towards the anterior end. It is best to use an upward-pointing direction with the scissors. As you cut the skin, in back the skin to expose the gut. 7. When you have successfully opened the earthworm, inspect the gut and moisten the worm with earthworm saline. If the gut is not damaged, continue with the next step. Dissection: removing the gut 1 . With the gut exposed, use a blunt probe to dissect away the septa that connect the underside of the gut to the body wall. You only need to expose 3-5 CM of the anterior gut. 2. When the gut is loosened from the body wall, again check to make sure it is not torn. 3. Tie a 20 CM piece of strong thread to the gut anterior to the pharynx and another piece 3-5 CM posterior to the pharynx. You should have 10-15 CM of loose thread available after you tie off the gut so that you can attach the gut to the organ bath and force transducer. 4. Using scissors, carefully remove the gut section from the earthworm. Mounting the gut in the organ bath 1 . Tie the posterior end of the earthworm gut to the mounting hook and mount the hook on the ring stand so the gut is in the organ bath. The distal end of the intestine should be 1 CM from the glass hook. Be sure to hold on to the thread on the anterior end. 2. Lower the force transducer on the microdensitometer its lowest position. 3. Tie the thread on the anterior end of the gut (pharynx end) to the force transducer. The gut should be slack. 4. Carefully raise the micrometeorites by turning the adjustment knob until the gut is under slight tension. NOTE: Be extremely careful not to overstretch the gut during this step. The gut is very delicate and could tear easily. 5. Make sure the drain stopcock on the organ bath is closed. Fill the organ bath with normal earthworm saline. The gut should now be completely submerged. If the gut is not completely submerged, you may need to re-tie the lower thread to the hook. [pica] Figure 1. The earthworm gut segment mounted in the organ chamber for recording. The ring stand and force transducer are not shown. Figure 2. Anatomy of the earthworm gut section. Exercise 1: Recording baseline data 1. From the Chart view window, click Start to begin data recording. 2. Observe your recording for five minutes. The contraction rate and strength should increase and become regular as the anesthesia wears off. 3. Make sure you have at least two minutes of consistent baseline data before proceeding. Figure 3. Typical recording of an earthworm gut segment under normal conditions. Exercise 2: Effect of neurotransmitters on contraction rate and force 1 . Drain the normal earthworm saline from the bath by opening the stopcock valve and draining the contents into a beaker placed underneath the bath. 2. Replace the solution with saline containing acetylenes. Pour the saline down the side of the organ bath chamber to minimize disturbances to the gut tissue. 3. Add a comment to your trace called acetylenes, and record for five minutes. 4. Drain the organ bath and replace it with epinephrine saline. 5. Add a comment to your data called epinephrine. 6. Record the response for five minutes. Drain the organ bath, and refill it with normal saline. 8. Add a comment called Wash and record for three minutes. Exercise 3: Effect of temperature on contraction rate 1. Record the temperature of the normal saline in Table 2 of your Data Notebook. 2. Drain the saline from the organ bath. 3. Replace the normal saline with cold earthworm saline. Pour the saline down the side of the organ bath chamber wall to minimize disturbance to your preparation. 4. Add a comment to your data file called cold. 5. Record the saline temperature in Table 2 of your Data Notebook. 6. Record data for five minutes. Drain the cold saline and replace it with warm saline. Record the temperature of the warm saline in Table 2 of your Data Notebook. 8. Add a comment called warm to your data file and record for another five 9. Drain the warm saline and replace it with normal (room temperature) earthworm saline. 10. Add a comment called normal and record for three minutes. Exercise 4: Effect of extracurricular ions on contraction 1. Drain the normal saline from the organ bath and replace it with saline marked high Ca+. 2. Add a comment to your data called high calcium, and record for five 3.