Lab #4: Comparative Anatomy

Question 1

Frontal/Coronal Plane

Answer 1

Splits subject into a FRONT and BACK
(one side will have mouth and one side will have back of head)

Question 2

Transverse Plane

Answer 2

Cuts subject in half between upper body and lower body –> Think of cutting a banana into slices

(Ex: Cut you’d make if you wanted to look at the ring structure of the diaphragm)

Question 3

Sagittal Plane

Answer 3

Cuts someone in half between their eyes

Question 4

Superior and Inferior

Answer 4

(For biped)
Superior = Towards top of head
Inferior = Away from top of head (towards feet)

Question 5

Rostral and Caudal

Answer 5

(For quadriped)
Rostral = Towards nose/beak
Caudal = Away from head

Question 6

Anterior and Posterior

Answer 6

(For biped)
Anterior = Stomach side (face side)
Posterior = Back side (butt side)

(Front and back)

Question 7

Ventral and Dorsal

Answer 7

(For quadriped)

Ventral = Stomach side

Dorsal = Back/spinal side
–> (Think of a dorsal fin on a whale, it’s along their spine)

Question 8

Lateral and Medial

Answer 8

(Midline reference is between eyes)
Lateral = Away from midline
Medial = Towards midline

Question 9

Proximal and Distal

Answer 9

Used in reference to the point of origin of a given component (typically limbs)

Proximal = Closer to point of origin/center of body
Distal = Away from point of origin/center of body

Ex: Hand is distal to the elbow
Ex: Stomach is proximal to the colon
(closer to the point of origin of the GI tract = esophagus)

Question 10

Determine the following planes

Answer 10

Question 11

Dissecting Needle

Answer 11

Slender tools with one end tapered to a sharp point

Used to separate and manipulate delicate tissues

Question 12

Blunt Probe

Answer 12

Slender tools with one end tapered to a rounded point

–> Used for separating tissues, lifting structures, and exploration of internal anatomy (generally used for larger tissues)

gentle tools! They are good for detailed examination without causing damage

Question 13

Forceps

Answer 13

Small tweezer-like tool

–> Used for grasping, holding, or manipulating tissues

Question 14

Scissors

Answer 14

Cut through tissues cleanly and precisely

Question 15

Cutters

Answer 15

Used to cut through bone and connective tissue (harder structures)

Question 16

Worm / Isopod / Rat:

Gas Exchange Surface

Answer 16

Worm = Skin

Isopod = Pleopod Lungs

Rat = Alveoli

Question 17

Worm / Isopod / Rat:

Blood Pump + vessels

Answer 17

Worm = Aortic Arches

Isopod = Heart

Rat = Heart

Question 18

Worm / Isopod / Rat:

Circulatory System

Answer 18

Worm = Closed system (blood)

Isopod = Open system (haemolymph)

Rat = Closed system (blood)

Question 19

Worm GI System Components

Answer 19

1) Mouth
2) Pharynx
3) Esophagus
4) Crop –> Stores food
5) Gizzard –> Grinds food
6) Intestine
7) Anus

Question 20

Isopod GI System Components

Answer 20

1) Mouth (containes mandibles + millipedes)
2) Foregut (esophagus + stomach)
3) Hepatopancreas (produces digestive enzymes –> area of food digestion and absorption)
8) Hindgut (digestion/absorption + stool packaging)
9) Rectum
10) Anus

Question 21

Rat GI System Components

Answer 21

1) Mouth
2) Esophagus
3) Stomach
4) Small intestine (+ liver and pancreas)
5) Colon
6) Rectum
7) Anus

Question 22

Role of maxillipeds and mandibles in isopods

Answer 22

Mandibles = responsible for the chewing of food (like a jaw)

Maxillipeds = allow for proper orientation of food within mouth so that mandibles can chew it

Question 23

Worm Excretory System

Answer 23

Consists of NEPHRIDIA (acts similar to human kidneys)

Filter waste from the coelemic fluid (Like ISF) and removes it through pores in the body

Question 24

Rat Excretory System

Answer 24

The renal system –> Utilizes the kidneys to filter out the blood; any filtered material gets sent to the ureters and bladder for excretion

Question 25

Isopod Excretory System

Answer 25

1) Maxillary glands = filters hemolymph; any filtered material leaves the body through the maxillary glands

2) Water Conductance System (directs all water to the pleopods to maintain moisture of the gas exchange surface)

3) Hindgut –> Packages stool for exit

Question 26

Worm Circulatory System: How do the aortic arches act as a heart?

Answer 26

They connect the dorsal and ventral blood vessels!

Question 27

Label the following external worm features:
1) Anus
2) Setae
3) Clitellum
4) Prostomium
5) Mouth

Answer 27

Question 28

What is the prostomium?

Answer 28

In a worm it is a sensory organ near the mouth that allows the worm to sense its environment

–> Allows worms to “feel” their way through the soil

Question 29

What is the clitellum?

Answer 29

Reproductive region!

Thickened glandular and non-segmented section of the body wall near the head (that secretes a viscid sac in which eggs are stored)

Question 30

Which end of the worm was the first incision made during dissection?

WHY?

Answer 30

The posterior end!
–> End with the anus

We cut here to avoid any damage to the organs of study on the anterior end that could occur if we made an incision there

Question 31

Why did we not cut directly down the center of the earthworm?

Answer 31

To prevent cutting the dorsal blood vessel

Question 32

What are the three main body regions of isopods?

Answer 32

1) Cephalothorax (head)
2) Pereon (thorax)
3) Pleon (abdomen)

Question 33

Characteristics of the isopod pereon

Answer 33

Segmented (usually around 7 segments)

For each Segment:
Ventral Side = Pair of pereopods (feet)
Dorsal Side = Tergite (exoskeleton)

Question 34

What is located on the ventral side of the pleon?

Answer 34

The pleopods (lungs)

Question 35

What is the pleotelson?

Answer 35

Last segment of the pleon (abdomen)

–> Has a pair uropods attached to it

Question 36

Label the following:

Answer 36

Question 37

What are the components of isopod antennae?

Answer 37

1) Peduncle (major portion of the antennae)
–> proximal portion of the antennae
–> Consists of multiple longer segments

2) Flagellum (end of the antennae)
–> Distal portion
–> Small end of the antennae that contains multiple small segments