Rattus norvegicus
“Norway Rat”
2018
You are to primarily find the
following structures and know something about their physiology by using the
assigned vocabulary assignment and the lab manual for this investigation.
Check each item off as you go along. Note: “right and left” is based on the
specimen’s “Right and Left” The following items may be used for a “lab
practical” and/or an “examination” at the end of the lab or year. Care,
respect, and professionalism is to be adhered to
throughout the lab. You will be graded on how well you stay on task and
on identifying the structures. Be prepared for periodical questioning
throughout the activity.
External
Features: p5
¾
Pinna
¾
Eyelids
¾
Nares
¾
Anus
¾
*
Female urogenital structures: ie vaginal orifice (see
p33)
¾
*
Male urogenital structures: ie scrotum (see p35)
* Pending on which gender you
have, find someone else in the class who has the opposite and note their
anatomy
Skinning the Rat: p4-6
- No need to worry about “pinning” specimen.
- If no “hole” in neck, create your own to begin the process.
- Skin is “paper-thin”; be CAREFUL NOT to cut muscle.
Muscular
System (Ventral: Front): p8-13
- no need to remove or cut; just identify
¾
Masseter
¾
Pectoralis
Major
¾
Pectoralis
Minor
¾
Triceps
Brachii
¾
Linea
Alba (whitish (non-muscle) membrane)
¾
Rectus
Abdominis
¾
External
Oblique
¾
Gracilis
Muscular
System (Dorsal: Back): p15-19
- no need to remove or cut; just identify
¾
Clavotrapezius
¾
Acromiotrapezius (and/or Spinotrapezius)
¾
External
Oblique
¾
Biceps
Femoris
¾
Fascia
“Lumbodorsal” (whitish (non-muscle) membrane)
Throat
and Oral Cavity: p19-22
¾
Lymph
Node(s) ; (3-4)
¾
Mandibular
Gland(s) ; (2) ; (remove clear membrane to
see)
¾
Tongue
(may not see well, just make note of where the structure is located)
¾
Teeth
Before Moving On, Ask to Get Permission at This Time / Q&A May
Follow
Cutting to Expose the Internal Structures: p22 (may again use p4 as a guide)
Abdominal
Cavity and Digestive System: p22-24 (Note: Cut muscle off or aside to view)
¾
Liver
(optional: median, left, right, and caudate lobe); gall bladder (stores bile)
found in humans, not the rat
¾
Stomach
(look under liver) [cut the stomach long-wise and look inside]
¾
Esophagus
(note: best seen if you look under trachea (wait to view when you get to the
“Respiratory System”)
¾
Pancreas
(between small intestine and stomach; within mesentery; delicate, red or
brown “granular” looking)
¾
Spleen
(brown, flag-like organ on rat’s left side)
¾
Small
Intestine (optional: duodenum (beginning), jejunum (middle), ileum (end))
¾
Peritoneum
(clear/thin membrane between intestines)
¾
Cecum
(or Caecum) ; (between small and large intestine;
“dead-end” pouch) ; humans have “appendix” on cecum
¾
Large
Intestine (Colon) (optional: ascending (beginning), transverse (middle), descending (end))
Before Moving On, Ask to Get Permission at This Time / Q&A May
Follow
Circulatory System: p24-31 (Note: Must cut through
sternum and remove/break ribs back to view)
¾
Thymus
Gland (top of the heart; lightly brown/whitish)
¾
Pericardium
(clear/ thin membrane over heart) ; may have fallen to either side of the heart
¾
Atrium
or Atria (pl.); (r./l.)
¾
Ventricle(s);
(r./l.) [cut heart
long-wise to see them (Do Not Remove)]; blue = right ventricle; red = left
ventricle.
Locate the Following Primarily via handout/diagrams Only:
¾
Vena
Cava (Anterior (Superior) or Posterior (Inferior))
¾
Aortic
“Arch” (Aorta) [cut away thymus gland to see]
¾
Aorta
(Thoracic (behind lungs) or Descending (behind intestines)
¾
Renal
Veins and Renal Artery(ies)
; (off the kidney)
Respiratory
System: p24-26
¾
Trachea
(white cartridge ringed structure in throat and down towards lungs) /
reminder: find under, the Esophagus
¾
Lung
(note that there are lobes (sections of the lung))
__ Diaphragm (muscle between lungs and the liver);
(you may have cut it in half without knowing)
Urinary
Structures: p32-33
¾
Kidney(s) ; (2)
¾
Urinary
Bladder
Female/Male
Genital Structures: p33-35
* pending on your specimen, find someone with the other gender to
view their structures (if no one; see text)
Female: ¾
Ovary
(optional: oviducts) ¾
Uterus
(Uterine Horns): Note: if round circular structures = pregnant ¾
Vagina |
Male: ¾
Testis
(optional: epididymis) ¾
Seminal
Vesicles ¾
Penis |
Central
Nervous System: p36-39
¾
Spinal
Cord [cut a section of vertebra ~5 cm (~2in.) out, then cut section
lengthwise to see the white/pinkish cord]
¾
Brain
[carefully cut “around” skull through the eye sockets; remove skull top
to view (Do Not Remove)]
¾
Cerebral
Hemisphere of Brain (Cerebrum in humans)
¾
Cerebellar
Hemisphere and Vermis Area of Brain (Cerebellum in humans)