Biology 8 Lesson 5: Practice Observing cells and tissues
1. Summary of theory
1.1. Objectives of the experiments
– Prepare a temporary specimen of skeletal muscle tissue.
– Observe and draw cells in ready-made slides: cells of oral mucosa (epidermal tissue), cartilage tissue, bone marrow, striated muscle tissue, smooth muscle tissue. Distinguish between the main parts of the cell including the plasma membrane, cytoplasm, and nucleus.
– Distinguish the different points of epithelial tissue, muscle tissue, connective tissue.
1.2. Laboratory instruments
Tools are prepared in groups (4 to 6 students) including:
– 1 microscope with magnification 100 to 200 (10 X 10, 10 X 20).
– 2 slides with slide.
– 1 scalpel.
– 1 sharp needle.
– 1 lancet needle.
– 1 cleaning cloth, absorbent paper.
– 1 frog or clone or a piece of fresh lean pork.
– 1 vial of 0.65% NaCl physiological solution, with a straw.
– 1 vial of 1% acetic acid, with a straw.
– Set of slides: epidermal tissue, cartilage tissue, bone beak, smooth muscle tissue (the set of slides can be used for 2-4 groups, when observing the available slides, the groups can be exchanged).
2. Content and Procedure
2.1. Making slides and observing skeletal muscle cells
Steps to take:
– Cut the skin of a frog’s thigh to get a muscle
– Use a sharp needle to make an incision along the muscle
– Use your index finger and thumb to press on both sides of the incision
– Take a lancet and gently pull and separate a thin thread
– Put the newly separated thin fiber on the glass slide, drop 0.65% physiological solution
– Cover the slide, drip acetic acid solution
Attention: Place the lamellar so that there are no air bubbles. To do this, first slice 1 cup of lamin into contact with a few drops of physiological solution, use a needle to support it, and then gradually lower the other edge of the slide to the slide (the amount of physiological solution needs to be moderate), if it is too much, the slide will will slide off the tip of the needle, hitting the bar right away, there will be lots of air bubbles.
– Observe under the microscope
– Distinguish between the parts of the cell: membrane, cytoplasm, transverse striations, nucleus. Review the characteristics of striated muscle tissue.
2.2. Observation of other tissue types
Observe in turn under the microscope the epidermal tissue, cartilage tissue, bone tissue, smooth muscle tissue, striated muscle tissue.
3. Harvest report
3.1. Summary of the method of making a skeletal muscle tissue specimen
– How to proceed:
- Step 1: Slice the skin of the frog’s thigh, take the thigh muscle or a piece of fresh pork, and place it on the slide.
- Step 2: Use a sharp needle to make an incision along the muscle sheath, use your thumb and index finger to place both sides of the incision, gently press, at this time, the muscle cells can be seen.
- Step 3: Use a needle to gently push the muscle cells away from the muscle to stick to the glass plate, then remove the muscle.
- Step 4: Put a few drops of 0.65% NaCl physiological solution on the muscle cells, cover the slide, and observe under the microscope.
- To see the nucleus, add a drop of acetic acid
- Cover the yeast so that there are no air bubbles
- Microscope adjustment from small objective to large objective
– Requirements: Observe the parts of the cell such as: membrane, cytoplasm, transverse striated, nucleus.
3.2. Draw pictures and fully annotate the observed tissues
– Students observe the specimen and draw back in their harvest the types of tissues that have been observed.
– Here are some pictures and characteristics of some types of tissues:
- Epidermal tissue: cells arranged closely together
- Cartilage tissue: only 2-3 cells
- Bone tissue: many cells
- Muscle tissue: many cells, long
After studying the lesson Observing cells and tissues you need:
– Reinforcing learned knowledge.
– Prepare temporary specimens of skeletal muscle tissue.
– Observe the specimens, distinguish the parts.