Pithing Process and Dissecting Process (Pictures and information are from internet references)

1. Prepared by:
Ms. Jasmine Nikki M. Versoza

2. FROG VS. TOAD

3. FROG VS. TOAD
FROG
 Have a narrow body
 Take long high jumps
 Have longer hind legs
 Need to live near water
 Have higher, rounder, bulgier eyes
 Have smooth, moist skin that makes them look
“slimy”

4. FROG VS. TOAD
TOADS
 Have a wider body
 Have rough, dry, bumpy skin
 Have lower, football shaped eyes
 Have shorter, less powerful hind legs
 Do not need to live near water to survive
 Run or take small hops rather than jump

5. Warm-Up
What do you think of dissection?
What do you like? What do you
dislike? Which organs do you want
to see? Why?

6. DISSECTION
to cut a part and see or to
separate and clean the
structures

7. Prepared by:
Ms. Jasmine Nikki M. Versoza

8. SAFETY MEASURES
 Laboratory Gown- to protect
your uniform
 Close shoes- gives safety to
foot from dropped scalpels or
sharp instruments

9. SAFETY MEASURES
 Gloves- to avoid the contact from
preservatives and other chemicals
 Goggles- to protect the eyes
against any foreign body during
cutting

10. Prepared by:
Ms. Jasmine Nikki M. Versoza

11. DISSECTING PROBE
 used for tearing
connective tissues
 used for feeling the
structures like vessels
and nerves

12. SCALPEL
 used to cut the tissue and
dissection of tough
connective tissue
 used to divide the vessels,
pedicels and other
structures.
 used for the sharp
dissection

13. DISSECTING FORCEPS
 Used for pulling or
tearing
 Used to grasp, lift and
hold the tissue

14. SCISSORS
 used in cutting and
sectioning of tissue
 used to cut tough
structures like tendons,
ligaments

15. HAEMOSTATIC FORCEPS
 Artery forceps
 used to catch/clamp
and to crush the tissue
 used for strong
grasping and holding
and catching

16. Prepared by:
Ms. Jasmine Nikki M. Versoza

17. DIRECTIONAL TERMS
Describe the positions of
structures relative to other
structures or locations in the body

18. SUPERIOR OR CRANIAL
Toward the head end of the body
Upper part of the body
Example: the hand is part of the
superior extremity

19. INFERIOR OR CAUDAL
Away from the head
Lower Part of the body
Example: Foot

20. ANTERIOR OR VENTRAL
Front part of the body
Example: The kneecap is located
on the anterior side of the leg.

21. POSTERIOR OR DORSAL
Back part of the body
Example: The shoulder blades are
located on the posterior side of the
body.

22. MEDIAL
Toward the midline of the body
Example: The middle toe is
located at the medial side of the
foot.

23. LATERAL
Away from the midline of the
body
Example: The little toe is located
at the lateral side of the foot.

24. Prepared by:
Ms. Jasmine Nikki M. Versoza

25. BODY CAVITIES
 The cavities are spaces
inside the body that
contain the internal
organs.
 The two main cavities are
called the ventral and
dorsal cavities.

26. Prepared by:
Ms. Jasmine Nikki M. Versoza

27. Pinning the Frog
 Rinse the frog in water.
 Place it in the dissection
pan on its dorsal side.
 Pin the limbs to the
dissection pan. Why?

28. Incision 1-Skin

29. Incision 2- Skin

30. Skin Separation

31. First Muscle Incision

32. Cutting The Chest Bones

33. Horizontal Muscle Cut

34. Muscle Separation

35. LAYER 1: Liver and Heart
 Find each of these organs in the first layer under the
muscles.

36. 1. LIVER
 The liver is a large, brownish colored organ covering most
of the body cavity.

37. 2. Heart
 It is a small triangular shaped organ between the front
legs and anterior to the liver.

38. LAYER 2: Gall Bladder, Stomach,
and Small Intestines
 Use the tweezers to lift up the liver to reveal the second
layer of organs.

39. 3. Gall Bladder
 Examine the gall bladder. Under the liver, we see a small,
greenish sac. This is the gall bladder.

40. 4. Stomach
 The stomach looks like a sac on the frog's left side (on
your right). It is a large firm organ.

41. 5. Small Intestine
 The small intestine is a
long, folded, tube like
organ that is posterior
the stomach.
 It is similar in color to the
stomach, but smaller in
diameter.

42. LAYER 3: Lung and Pancreas
 Reveal layer three.
 Remove the liver to
see the organs in layer
three.
 The liver is easier to
remove if you remove
the gall bladder and
heart at this time.

43. 6. Lungs
 The lungs are difficult to locate in a preserved frog.
 They're at the anterior end of the body cavity on either
side of the heart.

44. 7. Pancreas
• You can't see the pancreas without lifting the stomach and
intestines with the forceps.
• The pancreas is a thin, yellowish ribbon.

45. Do you have a Male or a Female
Frog?- Layer 4

46. Prepared by:
Ms. Jasmine Nikki M. Versoza

47. Pithing Process
1. Hold the frog facing away from your body, with
the inferior extremities.
2. Grasp the frog with your first two fingers: first
finger on the nose, second finger under the jaw.
3. Move probe down midline until you come to the
soft spot. Frog skull is fairly hard cartilage; soft spot
is at the end of the skull.

48. Cranial
Cavity of a
Frog

49. 4. Insert the needle quickly into the cranial vault and
sever the brain and spinal cord.
5. Move the probe into the cranial vault and move it
from side to side to destroy the brain.
6. Test for reflexes to confirm that sensory
perception has been destroyed and ensure that the
spinal cord is still intact, although it is now in shock.
Pithing Process

50. Corneal
Reflex

51. Prepared by:
Ms. Jasmine Nikki M. Versoza

52. GUIDE QUESTIONS
1. How could you tell that the frog was a male or
female?
2. What was the largest organ in the frog?
3. Which organs had two or more parts?
4. Is the heart anterior or posterior to the lungs?
5. What two pieces of safety equipment did we
wear?

53. GUIDE QUESTIONS
6. What are the tools that we used?
7. Where do we place the pins in the frogs?
8. How many pins did we used on the frog?
9. What was the smallest organ we looked at?
10.Which organ looked like noodles?

54. How could you tell that the frog was a
male or female?
The presence or
absence of eggs

55. What was the largest organ
in the frog?
Skin

56. Which organs had two or more
parts?
Liver
Lungs
Intestines

57. Is the heart anterior or
posterior to the lungs?
The heart is anterior to
the lungs.

58. What three pieces of safety equipment
did we wear?
Laboratory Gown
Gloves
Face Mask

59. What are the tools that we used?
Pins
Scalpel
Scissors
Pithing needle

60. Where do we place the pins in
the frogs?
One in each wrist, one in
each leg, and one through
each flap of muscle and skin

61. How many pins did we use
on the frog?
Six pins were used on
the frog.

62. What was the smallest organ we
looked at?
Gallbladder is the
smallest organ that we
looked at.

63. Which organ looked like
noodles?
Intestines are noodle-like
organ in terms of
appearance

64. Study this picture carefully for a
couple of minutes…

65. Label the Picture