But Why????? Because studying the rat muscles is almost like studying the human muscle system Comparative Anatomy Many of the names and functions of the rat’s muscles are the same as the human

What up with rats? They originated in Asia and migrated to Europe in the mid 1500s They made it to America by stowing away on ships, then spread across the continent into many habitats Today they are a nuisance because they eat fruits and grains that humans need , attack small animals , and live in crowded urban areas.

Rats are Valuable Used for scientific and medical research Comparative Anatomy allows students to study the rat and apply knowledge to human anatomy, without dissecting a human…

Comparative Anatomy

Rat Taxonomy Scientific Name: Rattus norvegicus (genus species) Common Name: Rat Kingdom- Animalia Phylum- Chordata Class- Mammalia Order- Rodentia http://dcfud.smorgasblog.com/userimages/rat.bmp http://www.gisbornesc.vic.edu.au/home/jans/home/rat.htm

Rat Dissection General Information Rat Guide: Gives you the information necessary to do the lab Worksheet: Where you will record any information, Exam Grade, will be left here every day. Rat Practical: at the end of the dissection. Will have to identify muscles on the rat. Exam Grade Daily exit ticket on the worksheet as each section is completed. Will need to rehearse the muscles and point them out to me. Daily Participation Grades also will be taken.

Dissection Worksheet Turn in one per partner Will be left here every day The entire section will need to be complete before sign off can occur It is best to work the section questions and table the day before you dissect that set of muscles Utilize google or the anatomy book to determine equivalent muscle names and functions for the rat and human

Dissection Equipment Common Equipment Scissors, scalpel, dissecting pins, dissecting needle, forceps, dull probe, dissecting pan, gloves, apron, safety glasses

External Anatomy Do you remember the anatomical directions? Toward the midline Toward the back (upper surface of body) Toward the tail Toward the side Farthest from the point of attachment Toward the belly (underside of body) Closest to the point of attachment Toward the head

External Features Know these external features for the practical!!!!

External Features Mammary Papillae Urethral, Vaginal Orifice Pinna Anus Nares Vibrissae

Objective for the Day Review prior day and prepare for quiz Observe and then apply the steps for skinning the rat Reinforce the steps for clean up Dissect the head and throat muscles and compare them to the human muscle system Prepare for the next class by comparing chest and medial muscles

Skinning the Rat Make a small snip into the skin layer only

Skinning the Rat Following the dashed lines in your guide, make a mid ventral incision being careful to lift the skin as you cut. Keep the tips of the scissors pointed up.

Skinning the Rat Use your dull probe to separate the skin from the muscle layer. Complete the rest of the cuts by following the drawing in your packet.

Steps to Remove the Skin After completing all the ventral cuts, loosen all skin away form the muscle layer below Some subcutaneous muscles may have to be cut to completely loosen the skin from the trunk area The layer of skin will not be completely removed. It will be used to cover the rat up for storage overnight. Snug as a bug in a rug.

CLEAN UP PROCEDURE A. Wrap up the rat in its own skin B. Place it in your labelled Ziploc bag C. Spray the rat with preservative D. Place the bag in designated box outside of Mrs. B’s door E. Clean up tools, rinse them (no soap), pat them dry, and sort them back into the correct tray F. Rinse the dissecting tray and stagger stack the trays on the side of the sink to dry overnight G. Wipe down your table and throw away all trash   H. Help others clean up I. Return to the room to continue working on worksheet until the end of class

Head and Throat Muscles Masseter Mylohyoid (beneath the digastric) Digastric Sternohyoid Sternomastoid Sternomastoid

Chest and Medial Muscles of the Front Leg Biceps Brachii Pectoralis Major Epitrochlearis Pectoralis Minor

Shoulder and Lateral Muscles of the Front Leg Brachialis Flexors Extensors Extensors Extensors Flexors Extensors Extensors Flexors

Shoulder and Lateral Muscles of the Front Leg Lattisimus Dorsi Acromiotrapezius Spinotrapezius Spinodeltoid Acromiodeltoid Clavotrapezius Cleidobrachialis Serratus ventralis Triceps Brachii

Hip and Lateral Muscles of the Hind Leg Gluteus superficialis Semitendinosus Biceps femoris

Hip and Lateral Muscles of the Hind Leg Gastrocnemius Soleus Tibialis Anterior

Hip and Medial Muscles of the Hind Leg Rectus Femoris Pectineus Vastus medialis Adductor longus Adductor magnus and brevis Gracilis

Abdominal Muscles External Oblique Internal Oblique Transversus abdominis ( not shown), is layer below the internal oblique Rectus abdominis