Mink Dissection – Laboratory Guidelines
1. BE PRESENT AND ON TIME!!
a. The only good reason for missing lab is DEATH (your own).
b. You may be given notes or special instructions during the first few minutes of lab. Make special note of any changes in materials to be used or procedures to be followed.
2. BRING MATERIALS/SUPPLIES.
a. Bring your laboratory manual and notebook to class everyday.
b. Be sure to put your name on everything (including boxes of gloves, if you brought them).
3. COME PREPARED TO WORK.
a. Prepare yourself BEFORE lab by reading the assigned exercise. It is important to have some understanding of what you are to do since the class periods are not very long, and some classes are large.
b. Be prepared for a poptest on the material covered the day before or material to be covered each day.
4. CHECK IN.
a. Use only equipment that is assigned to you.
b. Each day you will assemble the following dissection material: dissection tray and specimen, blunt probe, sharp probe, forceps (tweezers), scissors, and a scalpel.
c. BEFORE YOU BEGIN EACH DAY, check to see that all dissection equipment is clean and in place. Report any dirty or misplaced equipment to the instructor immediately. Dirty or misplace equipment will result in a daily grade of zero for the prior users.
5. BE SAFE.
a. NEVER eat, drink, or chew gum while dissecting in the laboratory.
b. Report any injuries to yourself or damage to equipment IMMEDIATELY.
c. Follow instructions precisely and proceed only when you understand them clearly. Do not skip any sections.
6. RECORD EVERYTHING.
a. Although it will be necessary for you to work within a group, try to remain independent when making observations and drawing conclusions. Remember that lab practicals will be taken without the aid of other group members.
b. Each day, record what you did and what structures you observed. These observations will be your daily log and will be placed at the end of your Mink Lab Report.
c. Daily instructions will be given concerning homework and lab report assignments.
7. MINK LAB REPORT MUST INCLUDE:
a. Log of what you did each day and what features you found. This log will be placed at the end of the report.
b. Drawings as indicated by daily handouts.
c. Written assignments as indicated by daily handouts.
d. Guide sheets.
8. CLEAN UP.
a. At the end of the period, clean your table with 409 or Clorox wipes and wash the instruments you have used. After drying your instruments, return them to the proper places and dispose of wastes as instructed.
b. WASH your hands thoroughly before leaving the classroom.
9. GRADING.
a. Your grades on the dissection of the mink will be composed of:
i. Mink Lab Report (1 test grade)
ii. Muscle Lab Practical (1 test grade)
iii. Internal Anatomy Lab Practical (1 test grade)
iv. Daily Participation
I have read the above instructions and regulations and understand them.
______________________________________(student signature) ____________________(date)
Anatomy & Physiology
N. Roberson
Mink Dissection
Guide 1
INTRODUCTION
Your first task, before actually beginning the mink dissection, will be to review material covered earlier in the year, focusing on directional terms and anatomical terminology. You must also become familiar with the classification and characteristics of your mink. Please complete the following assignments.
1. In your laboratory manual (Laboratory Anatomy of the Mink) read pages viii, 1 and 3.
2. Prepare a TITLE PAGE to be placed in your Mink Lab Report. Do not number the title page.
3. Insert the Laboratory Guidelines directly after the title page and number it as PAGE 1.
4. Insert this instruction sheet (Guide 1) next and number it as PAGE 2.
5. Next, write a brief narrative (1/2 to 1 page) describing the classification, characteristics, and habitat of the mink. Number this as PAGE 3.
6. Review the directional and anatomical terms on page 5-6 of the lab manual.
7. The first drawing you are to make is one similar to that found on page 5 (fig. 1) in the lab manual. DRAW and LABEL the directional terms and planes of reference. This should be a WHOLE-PAGE DRAWING on unlined paper and should be entitled PLATE 1: DIRECTIONAL TERMS AND PLANES OF SECTION. It should be numbered PAGE 4. Remember that all drawings will be graded on neatness and accuracy, not artistic ability.
8. Next, handwritten on lined paper or typed, define the following terms:
a. anterior (cranial)
b. posterior (caudal)
c. ventral
d. dorsal
e. medial
f. lateral
g. frontal plane
h. sagittal plane
i. transverse plane
j. pectoral limb
k. pelvic limb
*Number this PAGE 5 and insert it into your Mink Lab Report.
9. The SKELETAL SYSTEM of the mink is very similar to that of man in many ways. Read pages 7-14 in the lab manual for a complete discussion of the mink’s skeletal system. We do not have disarticulated skeletons, so we will not compete this section of the lab.
10. Review your notes describing the human skeletal system. Write a BRIEF SUMMARY (no more than 1 page) describing the likenesses and differences between the human and mink skeletal systems. This should be numbered PAGE 6 of your Mink Lab Report.
REMEMBER THAT ALL DRAWINGS ARE TO BE MADE ON UNLINED PAPER.
Anatomy & Physiology
N. Roberson
Mink Dissection
Guide 2
THE MUSCULAR SYSTEM
Your mink has been skinned for you. Your task now is to clean the fat and fascia off so that muscle fiber directions can be seen and to separate each muscle from adjacent ones. Fingernails and the blunt probe are most useful. When cutting a muscle, first separate it completely from adjacent structures and pass the probe beneath the belly. Then cut downward to the probe with a scalpel from the outside. When cutting a number of muscles that run alongside one another in the same direction (such as muscles of the thigh), cut across the bellies of different muscles at different levels and reflect (fold back) the muscle halves.
Dissect the musculature on the LEFT SIDE OF THE ANIMAL ONLY, leaving the right side intact for the study of the nervous and circulatory systems. Where two depths of dissection are shown on one animal in the lab manual, the deeper is always on the animal’s left side.
Complete the following tasks:
1. Read pages 16-19 in your lab manual and review your class notes on the muscular system PRIOR TO LAB. Insert this guide as PAGE 7 in your Mink Lab Report.
2. As you did with the skeletal system, write a BRIEF SUMMARY describing the likenesses and differences between the muscular system of man and that of the mink. Please limit your discussion to one (1) page. (NOTE: It will be much easier to complete this assignment once you have completed the muscle dissection, but you need to watch closely for likenesses and differences as you dissect.) This summary should be numbered PAGE 8 of your Mink Lab Report.
3. Begin your dissection by carefully removing dermal muscle, fat, and fascia (connective tissue) from the neck, back, shoulder, and upper arm of the LEFT SIDE. This is best done using forceps and fingers, NOT A SCALPEL!!!
4. Following the instructions in your lab manual and the drawing at the top of page 17, identify the following muscles of the head and back, separating them as you go, but NOT CUTTING THEM:
a. TEMPORALIS
b. CLAVOTRAPEZIUS
c. ACROMIOTRAPEZIUS
d. SPINOTRAPEZIUS
e. LATISSIMUS DORSI
5. Once all members of your group are confident that they can identify the above muscles, proceed to identify the underlying muscles. Using a scalpel, cut THROUGH the belly of the SPINOTRAPEZIUS, ACROMIOTRAPEZIUS, and CLAVOTRAPEZIUS. Do not remove these muscles. Simply cut through the belly and pull back to either end in order to expose the underlying muscle layer. (This way you’ll be able to put them back into position when you get ready to review the muscle in step #4.)
6. Follow your manual and the middle drawing on page 17 to identify the following muscles of the underlying layer:
a. RHOMBOIDEUS
b. ATLANTOSCAPULARIS
c. SPLENIUS
d. OCCIPITOSCAPULARIS
e. OMOCERVICALIS
7. Make a full page lateral view DRAWING with the following muscles being labeled (use top drawing on page 17 as a guide, but make your drawing a full page):
a. TEMPORALIS
b. CLAVOTRAPEZIUS
c. ACROMIOTRAPEZIUS
d. SPINOTRAPEZIUS
e. LATISSIMUS DORSI
Label this drawing PLATE 2: SUPERFICIAL MUSCLE OF PECTORAL LIMB. Insert it into your mink lab report as PAGE 9.
8. Now make a full page lateral view DRAWING after step #6 has been completed. Label the following muscles (use the center drawing on page 17 as a guide):
a. OCCIPITOSCAPULARIS
b. SPLENIUS
c. ATLANTOSCAPULARIS
d. RHOMBOIDEUS
e. OMOCERVICALIS
Label this drawing PLATE 3: UNDERLYING MUSCLE OF THE PECTORAL LIMB. Insert it into your mink log as PAGE 10.
Anatomy & Physiology
N. Roberson
Mink Dissection
Guide 3
THE MUSCULAR SYSTEM (cont.)
Now that you have completed the muscles of the head and shoulder, you are ready to begin identifying the muscles of the left anterior limb (pectoral limb) and the chest.
1. Begin by using figure 13 on page 17 (top drawing) to locate the following muscles on the lateral surface of the pectoral limb:
a. TRICEPS (lateral head)
b. TRICEPS (long head)
c. DORSOEPITROCHLEARIS
d. SPINODELTOID
2. Now identify each of the above muscles on your mink. DO NOT CUT THEM, as we will go no deeper than this surface layer of muscles.
3. Go back to your drawing labeled PLATE 2 and add the 4 muscles that you just identified in step #2.
Musculature of the forearm is complex, and only the larger, more superficial muscles will be described. These muscles are divided into a DORSAL EXTENSOR group and a VENTRAL EXTENSOR group. Bellies of these muscles are covered by very heavy fascia.
4. Of the extensor muscles, the BRACHIORADIALIS is the only one we will identify by name. Locate it now. (See figure 15, page 19.)
5. The remaining extensor muscles will simply be called the EXTENSOR CARPI. Locate them.
6. The muscles located on the ventral surface of the forearm we will collectively call the FLEXOR CARPI. Locate them.
7. These muscles will be labeled on a later drawing of the mink’s entire ventral surface. Do go back now to PLATE 2 and add the BRACHIORADIALIS and EXTENSOR CARPI.
8. Now place the mink on its back. Using figure 17 on page 21 as a guide, separate and identify the following muscles:
a. PECTORALIS MAJOR
b. PECTORALIS MINOR
These muscles will be labeled later after you have identified the muscles of the neck and head.
9. Insert this instruction sheet into your Mink Lab Report as PAGE 11.
Anatomy & Physiology
N. Roberson
Mink Dissection
Guide 4
THE MUSCULAR SYSTEM (cont.)
Muscles of the head, neck, and abdomen.
Read pages 20-23 in the lab manual.
Place your mink on its back and begin removing as much connective tissue as possible from the neck region. Begin at the pectoralis muscles and clean anteriorly to the chin ON THE LEFT SIDE. This fascia will be EXTREMELY TOUGH! Use care not to tear the muscle tissue.
1. Place this instruction sheet into your mink lab report as PAGE 12. Then, using figure 17 on page 21 as a guide, identify the following muscles:
a. MASSETER
b. DIGASTRIC
c. MYLOHYOID
d. STERNOMASTOID
2. Also identify the hard MANDIBULAR GLANDS. These secrete saliva.
3. Cut and reflect the LEFT STERNOMASTOID. This will expose the STERNOHYOID, LARYNX, and TRACHEA. Locate each.
4. The THYROID GLANDS may be found alongside the larynx buried in fat. Attempt to locate them, but don’t be disappointed if you do not find them.
5. Concentrate now on the abdominal muscles. The lateral abdominal muscles of mammals consist of three superimposed sheets whose fibers run in different directions. The outermost layer is the EXTERNAL ABDOMINAL OBLIQUE. Locate it on your mink.
6. Slit and peel off a small section of the EXTERNAL ABDOMINAL OBLIQUE on the middle of the LEFT abdomen, about halfway up the body. BE CAREFUL – this muscle is about as thick as tissue paper. Under it you should see the INTERNAL ABDOMINAL OBLIQUE.
7. Slit the INTERNAL ABDOMINAL OBLIQUE (carefully) and see if you can find the TRANSVERSUS ABDOMINIS. Under this is the peritoneum and the abdominal cavity.
8. The abdominal muscles (external and internal oblique and transverses abdominis) attach with a fascia as they approach the ventral midline. Under this fascia, we find the RECTUS ABDOMINIS MUSCLE. Can you also find the LINEA ALBA?
9. Now make a FULL-PAGE drawing of the ventral surface of the upper body and label the following muscles (see figure 17):
a. PECTORALIS MAJOR e. MYLOHYOID i. EXTERNAL OBLIQUE
b. PECTORALIS MINOR f. STERNOMASTOID j. RECTUS ABDOMINIS
c. MASSETER g. MANDIBULAR GLAND
d. DIGASTRIC h. STERNOHYOID
This drawing should be PLATE 4. Insert it into your mink lab report as PAGE 13.
Anatomy & Physiology
N. Roberson
Mink Dissection
Guide 5
THE MUSCULAR SYSTEM (cont.)
ASSIGNMENT: Read pages 23-26 in the lab manual carefully. Number this guide as PAGE 14 and
insert it into your mink lab report.
You have already identified the LATISSIMUS DORSI of the back. Locate it again. The musculature of the back consists of numerous bundles of fibers attaching on the ilium, processes of vertebrae, ribs, and the occipital region of the skull. Note that much of the muscle along the spine is covered by a think, glossy fascia.
Now we are ready to identify muscles of the pelvic limb. Remove fat and fascia from the pelvic limb and posterior part of the body ON THE LEFT SIDE. If your specimen is male, leave the fat in the inguinal region; the testicles may be buried in it. Be PARTICLULARLY careful when working between the legs and under the tail because the SCENT GLANDS may not have been removed when the animal was skinned. YOU AND EVERYONE ELSE IN THE ENTIRE BUILDING WILL KNOW IF YOU PUNCTURE ONE!!!
1. Observe the lateral surface of the hind leg and identify the following muscles (see top drawing on page 24, figure 20):
a. GLUTEUS MAXIMUS
b. TENSOR FASCIA LATA
c. FEMOROCOCCYGEUS
d. SEMITENDINOSUS
e. BICEPS FEMORIS
f. SARTORIUS
2. Now cut and reflect the BICEPS FEMORIS near the middle. (See middle drawing, figure 20.) Be very careful as you cut the biceps femoris because the TENUISSIMUS often adheres to the under surface of it and may be accidentally cut.
3. Identify the following muscles you have exposed:
a. VASTUS LATERALIS
b. TENUISSIMUS
4. Turn your mink over and observe the medial surface of the thigh. Using figure 21 on page 25 as a guide, separate and identify the following:
a. SARTORIUS
b. GRACILIS
5. Now carefully cut and reflect the SARTORIUS and GRACILIS to expose the following muscles: