Dissection of the Rat
An Exploration of the Various
Organs Systems
General Rules
• No Food or Drink at your Station at all times
– Participation pts. Will be lost!!!
• Remain at your station at all times unless
instructed
• Keep track of all instruments (do a count everyday)
• No open toed shoes
• Do not cut anything unless instructed
• Always follow your Dissection guide
Dissection Tasks
• Researcher & Photographer:
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Sets up computer (obtains images & info.)
Wipes down the entire table table top
Takes photographs, prints & shares with group
Corrects all IQ’s for the group
Researches key information
Keeps the group in check with Dissection Manual
• Equipment manager:
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Cleans, dries, and returns all supplies to the appropriate places.
Organizes & counts all intruments
Assists with the Clean up procedures (pan, table, etc)
Makes labels/prepares them on pins
• Dissectors/Assistant( min. 2 people) - Observe the
dissection procedures and share with rest of the group.
Initial Procedures to Begin the Dissection
• Dissection Guide: turn to the appropriate Pgs. Beginning
through pg. 16 so you can answer the first two set of
Guiding Questions.
• Collect all the Instruments & place them in a pouch that
you have labeled with your period and group members.
• Freezer Bag: using a sharpie label your bags as follows
with your period and all lab group member.
• Choose a rat and give it a name. Choose both a male and
female name for now. You will verify the gender later
and circle that name on the bag then.
• Use the rat to help answer some of the guiding questions.
• Tie one piece of string on the upper extremities with
each end on each forelimb and another string on the
lower extremities (you will keep these strings tied on the
rat at all times.
Closing Procedures at the End of Class
• Obtain some paper towels and roll the rat in them then
place your rat into the labeled freezer bag.
• Make a TIGHT Seal with all the air evacuated out.
• Clean your tray and instruments.
• Put all your instruments in you pouch or box.
• Place tray, instruments, and rat in your designated drawer.
**You will store your Pan, Instruments, and Rats in the available
drawers located along the sides of the room.
**Spray down the ENTIRE table top with windex and
thoroughly clean it leaving no streaks.
**FOLD your Lab coats & stack neatly in the back
Return the dissection guides and computer back to the cart.
Instruments
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1 dissecting pan
1 Lg. Freezer Bag
4 pieces of string (25 in each)
2 forceps (fine & blunt)
1 scapel (pick up later)
2 blunt probes
4 sharp probes
14 pins (6 large & 8 fine)
2 scissors (large & fine point)
Water dropper & cup
Ruler (pick up later)
Index card (cut into labels) – need to bring some next week)
Day 1: Guiding Questions #1
1.
2.
3.
4.
5.
6.
7.
Make a list of instruments you’ll be using and the number of
each.
After reading the objectives of the lab, how many organs for
each system are you required to know and identify.
Name the two major regions of the integumentary system.
Name three functions of this system.
Name the four key parts to the skeletal system. What does
Hemopoiesis mean?
What is the only function of the muscular system? Name the
three parts of the body mentioned that the muscular system
plays a role.
Name the three parts of the nervous system. Which parts
make up the central nervous system?
Name two functions of the endocrine system. What chemical
is produced by the glands that make up this system? How is
this system different from the nervous system? Name the eight
types of organs that make up this system.
Guiding Questions #2
1. What purpose does the circulatory system serve?
What is it primarily composed of?
2. Name the six key structures that make up the
respiratory system. What purpose does this system
serve? Name the minute little sacs in the lungs that
help with gas exchange.
3. Name the six parts of the digestive system. Where
does digestion begin? Which part of the system is
used to remove water from the food?
4. What roles do the pancreas and liver play in the
digestive process?
5. Name one of the key waste products excreted by the
Urinary system. Name the four main organs of this
system.
6. Name the key structures of the male and female.
Guiding Questions #3
1. From your dissection guide which chapter discusses the
muscular system?
2. Before identifying the muscles the rat must be skinned.
The first incision to be made begins on the
surface of the _____ and continues down to the point
just anterior to the ______.
3. Circumvent cuts are made to the (right,left) by the
genetials and mouth. How does the guide suggest that
you separate the skin from the body?
4. Before separating the muscles and identifying them you
first need to remove the tough white connective tissue
that surrounds the muscles. Name this tissue.
5. Using Figure 14 (lateral view) list all of the muscles
labeled in the diagram. You will ID these in your rat
first.
Basic Procedure
1.
2.
3.
4.
Ventral Incision & Extension to the limbs
Separating skin from the underlying muscles
Separate the fascia off the muscle
Identify the indicated muscles
-Make labels for structures listed on overhead
Guiding Questions #3
1. From your dissection guide which chapter discusses the
muscular system?
2. Before identifying the muscles the rat must be skinned.
The first incision to be made begins on the ______ surface of the _____ and continues down to the point
just anterior to the ______.
3. Circumvent cuts are made to the (right,left) by the
genetials and mouth. How does the guide suggest that
you separate the skin from the body?
4. Before separating the muscles and identifying them you
first need to remove the tough white connective tissue
that surrounds the muscles. Name this tissue.
5. Using Figure 14 (lateral view) list all of the muscles
labeled in the diagram. You will ID these in your rat
first.
Lateral View of the Muscles
Separate & ID these Muscles (10 muscles)
-Masseter
-Sternomastoideus
-Spinodeltoideus
-Latissimus dorsi
-Triceps
-Brachialis
-Biceps femoris
-Gluteus Maximus
-Tensor fascia Latae -Semitendinosus
Please use the following in your guide:
Lateral View (Pg. 16, Fig 14)
Ventral View of the Muscles
Muscles to locate & ID from
Ventral view (14 muscles)
-Pectoralis major
-Pronator teres
-Palmaris longus
-Pectoralis minor
-External oblique
-Gracilis
-Vastus medialis
-Biceps brachii
-Flexor carpi radialis
-Triceps
-Rectus abdominus
-Sartorius
-Gastrocnemius
-Semimembranosus
Guiding Questions #4
(Ch. 4 Digestive system)
1.
7.
Name the three pairs of salivary glands commonly found in the
rat.
Within the mouth cavity if you were to look inside you would
observe a hard and soft palate. Where are they specifically
located?
After opening the abdominal cavity you should be able to
locate the esophagus and follow it to the stomach. Name two
structures that would be located next to the stomach.
On page 28 of your guide sheet the diaphragm separates two
cavities. Name them.
How many lobes is the liver is divided into? Name them.
Name the three regions of the stomach. How is the great
omentum different from the lesser omentum?
Where is the spleen located with reference to the stomach?
8.
Name all of the structures discussed from #11
2.
3.
4.
5.
6.
to #19.
Digestive System
Lg. Intestine
Cecum
Ascending colon
Oral cavity
Mouth
Tongue
Salivary
glands
Pharynx
Transverse colon
Descending colon
Sigmoid colon
Esophagus
Liver
Sm. Intestine
Stomach
Duodenum
Jejenum
Ileum
(ileocecal
valve)
Pyloric
sphincter
Gallbladder
Pancreas
Small
intestine
Stomach
Small
intestine
Large
intestine
Rectum
Anus
Figure 21.4
Bile
Liver
Stomach
Gallbladder
Bile
Duodenum of
small intestine
Acid chyme
Pancreas
Figure 21.10A
Large Intestine Reclaims Water
• Undigested
material passes to
the large intestine,
or colon
Large
intestine
(colon)
– Water is absorbed
– Feces are
produced
End
of small
intestine
Small
intestine
Rectum
Anus
Nutrient
flow
Appendix
Cecum
Figure 21.11
Guiding Questions #4
(Ch. 4 Digestive system cont’d)
Tasks to still complete:
Finish separating the intestinal tract from the mesentery
Transect the intestine from STOMACH end off the
esophagus
-Measure the length of the intestines (____ cm.)
-Make a cross section of the stomach and make
observations
-Label all key structures
Guiding Questions #5
(Ch. 5 Circulatory system-Pgs 31-36)
1.
2.
3.
4.
5.
6.
What was injected into the veins and arteries of your rat? Why
was this done?
The pericardial membranes surround the
. Name the two
types of membranes present. How are these two membranes
different from each other?
Which area (chamber) does blood enter the heart? Name the
vein that drains blood from the lungs to the left atrium.
Name the structure that divides the two ventricles of the heart.
How many branches come off the aortic arch? Name them.
Where are the following arteries found?
-coronary, carotid, subclavian, hepatic, gastric, femoral, caudal and intercostal?
7.
8.
Is the jugular a vein or artery?
What is the difference between an artery and a vein? Which one
moves blood away from the heart?
Tasks to complete for the Circ.
System
• Find the FIVE major vessels off the aorta
• Cross section of the heart
• Trace major blood vessels in the arms and
legs
Thoracic Cavity
Internal Chambers of the Heart
Internal Structure of the Heart
Posterior view of the Heart
Valves within the Heart
See pgs 569-575
Pulmonary
artery
Aorta
11. vessel
Pulmonary
10.
vessel
artery
Superior
1.
vessel
vena
cava
LEFT
ATRIUM
RIGHT
2. chamber
ATRIUM
Pulmonary
veins
Pulmonary
9.
veinsvessels
Semilunar
3. valve
valve
Semilunar
8.
valvevalve
Atrioventricular
valve
Atrioventricular
7.
valvevalve
4. Inferior
vessel
vena
cava
5.RIGHT
chamber
VENTRICLE
LEFT
6. chamber
VENTRICLE
Figure 23.4A
RBC Pathway through the Circulatory System
Blood from Systemic Circuit

Vena cava (inferior & superior)

Right atrium
 (Tricuspid valve-AV valve)
Right ventricle
 (Pulmonary semilunar valve)
Pulmonary circuit –Lungs
(P. arteries LungsP. veins)

Left atrium
 (Bicuspid “Mitral” valve)
Left Ventricle
 (Aortic semilunar valve)
Aorta
(arch, coronary, carotid, & abdominal, renal, mesenteric, iliac arteries)
Arterial System
Guiding Questions #6
1. Name the five branches that come off the aortic arch.
2. How many chambers does the heart have? (After
splitting the heart in two). Name these chambers.
3. Find the following blood vessels in your rat and label
them: Carotid artery, Pulmonary artery, Vena Cava,
Aorta, Renal, and iliac arteries (left & right).
5. Name the gland that sits on top of the kidney. (see
Chapter IV.
6. The kidney are said to be “retroperitoneal” what does
this mean?
7. Name the small tubular structure that comes out of the
kidney and into the urinary bladder
Tasks to Complete for Urinary
System
• Trace the three main structures that come to
and from the kidney
• Trace the ureters from the kidney to the
bladder
• Locate adrenal glands
• Cross section of the kidney
Guiding Questions #7
1. When looking within the kidney, the outer layer is
called the __________ ________ and the inner layers
is called the ________ __________.
2. What function does the kidney serve?
3. Where does the ureter transport urine to? How many
ureters are there?
4. Name the gland that sits on top of the kidney.
5. Identify each structure as either male or female:
-Ovary
-Uterus
-Cowpers gland
-Prostate gland
-Vas deferens
-Epididymas
6. An oviduct is the same thing as a ________ _______
Water Balance and waste disposal
The Human Kidney & Nephron
Male Reproductive System
Female Reproductive System
Tasks to Complete for Reproductive
System
• Determine sex
• Find (2) major structures to verify the sex
Guiding Questions #8
1.
2.
3.
4.
5.
6.
7.
8.
Name the three layers of the meninges that covers the brain.
The cerebrum is composed of two hemispheres separated by a
longitudinal groove called the ________ _________.
Name the nerve fibers that connect the two hemispheres that is
easily viewed by a sagital section of the brain.
A highly convoluted structure found on the posterior part of the
brain is called the __________.
The most primitive and most posterior part of the brain that
tapers into the spinal cord is called the __________
___________.
How many ventricles (cavities) are found in the brain?
Name the gland that sits within the sella turcica.
How many pairs of cranial nerves emerge out of the brain?
Name 5 of these cranial nerves shown in Fig 27.
Be sure you have the following labels
and pin these on your rat
Set #1 (abdominal cavity)
-Liver
(4 lobes)
-Stomach
-Small intestine (D, J, I segments)
-Spleen
-Kidney (right)
-Aorta (abdominal)
-Iliac arteries
-Diaphragm
-Adrenal gland
-Mesentery
-Ureter
-Large intestine (caecum)
Set #2 (Neck & Thoracic cavity)
-Heart Heart (atrium, ventricle, septum)
-Aortic arch
-Jugular veins
-Trachea
-Thyroid gland
-Lung (5 lobes)
-Thymus gland
-Renal artery & vein
-Carotid arteries
-Pericardial membrane
-Inferior Vena Cava
-Coronary (artery or vein)
****
Final Set: Ovary & uterus OR testes, vas deferens
Contents of the Abdominal & Thoracic Cavities
Practice/Review Practicum
• Obtain your rat and label (3) structures (A, B, & C) for the region I Assign your
table.
• Be sure to make write your labels clearly with pin pierced in the structure
Station #1: Lateral muscles
Station #2: Ventral Muscles
Station #3: Neck
Station #4 & #5: Thoracic Cavity
Station #6 & #7: Abdominal cavity
Station #8: Reproductive Structures (male)
Station #9: Reproductive Structures (female)
** Number a blank sheet of paper from #1-27 (you’ll turn this sheet on Monday)
**At the conclusion (10 min prior) you will need to:
Clean up your table
-Turn in your rats
-Turn in all your instruments, placing them in the designated area in the back
-Spray & clean your drawers