Dogfish Lab

Question 1

The dogfish has a __ tail.

Answer 1

heterocercal

Question 2

The dogfish does not have a ___ fin.

Answer 2

anal

Question 3

Sharks have ___ skeletons

Answer 3

cartilaginous

Question 4

Why is it called a spiny dogfish?

Answer 4

spines in front of each dorsal fin

Question 5

Sensory features of the dogfish

Answer 5

• Ampullae of Lorenzini
• Eyes (lateral)
• Nares (ventral)
• Lateral line

Question 6

What are spiracles?

Answer 6

Modified gill slits; tissue closes over them during part of the respiratory cycle to prevent water from leaving

Question 7

How many gill pouches in the dogfish?

Answer 7

five

Question 8

What movement do pectoral fins control?

Answer 8

In the dorso-ventral plane

Question 9

What do dorsal fins do?

Answer 9

stabilizers

Question 10

What kind of scales does the shark have?

Answer 10

Placoid scales/denticles

Question 11

The dogfish’s spines are enlarged versions of ___

Answer 11

denticles

Question 12

Male sharks have these, females don’t

Answer 12

claspers

Question 13

What are the seven visceral arches in the dogfish’s splanchnocranium?

Answer 13

• mandibular
• hyoid
• five branchial

the first two are for the jaw, the others support interbranchial septa

Question 14

Two types of vertebrae in the dogfish

Answer 14

trunk and caudal

Question 15

One half of a dogfish gill

Answer 15

demibranch

Question 16

The two halves of a dogfish gill, plus the related blood vessels, internal septum, muscles, and nerves

Answer 16

holobranch

Question 17

Water flows ___ to blood flow in the dogfish

Answer 17

countercurrent

Question 18

How many chambers in the shark heart?

Answer 18

four

Question 19

Chambers of the shark heart

Answer 19

1. sinus venosus
2. atrium
3. ventricle
4. conus arteriosus

Question 20

The dogfish’s teeth are ____

Answer 20

homodont

Question 21

Dogfish have a tongue?

Answer 21

Not a true tongue, can’t move.

Question 22

The first gill slits

Answer 22

spiracular openings

Question 23

Two portions of the dogfish stomach

Answer 23

cardiac and pyloric

Question 24

rugae

Answer 24

longitudinal folds in shark stomach allowing expansion to accommodate larger pieces of food; sharks don’t chew

Question 25

Where is the spiral valve?

Answer 25

The ileum

Question 26

What does the spiral valve do?

Answer 26

Increases intestinal surface area (and length?) so more nutrients can be absorbed from the food

Question 27

How does the rectal gland help the shark osmoregulate?

Answer 27

Secretes NaCl with food waste

Question 28

2 bonus functions of the dogfish liver

Answer 28

1. oil-rich, so help with buoyancy (low specific gravity) | 2. the oils act as an energy store

Question 29

Are the urinary and reproductive systems in the dogfish considered separate?

Answer 29

No, they share common structures and have similar origins developmentally

Question 30

What are the two functional parts of the male dogifsh's kidneys?

Answer 30

Anterior- includes epididymis and tubules that provide secretions to help with sperm transport Posterior- excretory purposes

Question 31

Leydig's gland

Answer 31

tubules of the ductus deferens in the middle 2/3 of the kidney

Question 32

What does the upper portion of the female dogfish's kidney do?

Answer 32

non-functional

Question 33

Eggs are produced and released from the __. They move out of the ovary to the __, the opening to the __ that also opens into the body cavity.

Answer 33

ovary ostium oviducts

Question 34

This gland secretes a thin shell around groups of eggs (2-3).

Answer 34

Shell gland

Question 35

enlargements of the caudal half of the oviduct that connect with the cloaca

Answer 35

uterus

Question 36

The sperm travel down the __, receiving secretions from Leydig’s gland, toward the cloaca

Answer 36

ductus | deferens

Question 37

The ductus deferens starts out as the ___, which are responsible for urine transport from the ____ to the cloaca; however, this function shifts when males reach maturity, and urine transport transfers to the accessory ducts.

Answer 37

archinephric ducts | kidneys

Question 38

The archinephric ducts are __ in mature male dogfish.

Answer 38

highly coiled

Question 39

Fertilization in dogfish is___

Answer 39

internal

Question 40

Gestation time of dogfish

Answer 40

18-22 months, longest known for sharks

Question 41

Sexual maturity of dogfish

Answer 41

10 for males | 16 for females

Question 42

Unique function of kidneys in sharks

Answer 42

Extract urea from the urine and return it to the blood to regulate osmotic pressure