Fish Anatomy *extra credit*

Question 1

what is the difference between the fork length, total length, and standard length of a fish?

Answer 1

fork length: distance between the mouth -> fork of the tail
total length: distance from mouth -> tip of the tail
standard length: distance from the mouth -> peduncle

Question 2

what are the structures of the gills? How does water flow over them? Including the primary & secondary lamellae?

Answer 2

• Cranially, they are open to the gullet
• Caudally, they are open to the external environment
• Water flows continually over them through the mouth

Question 3

How many gill arches do fish have on each side?

Answer 3

4

Question 4

What are the two main functions of gills?

Answer 4

1. Need to obtain oxygen from the water
2. Respiration and excretion of ammonia

• gills are more efficient then lungs

Question 5

what are the 2 types of scales and know which one is found in bony (teleost) fish?

Answer 5

1. Ctenoid scales (elasmobranch) have a sandpaper-like finish
2. Cycloid scales (teleost) have a smooth outer surface

Question 6

Do fish have an outer, middle, or inner ear?

Answer 6

inner ear

Question 7

what are the 4 parts of the fish hear and know their characteristics?

Answer 7

1. Utricle: horizontal movement
2. Saccule: vertical movement
3. Bulbous area called the ampulla that contain the cupula
4. Lagena is part of the vestibular system

Question 8

Where is the electric organ in marine and freshwater fish? What is its function?

Answer 8

electroreception: detect electric fields
- used for: communication, navigation, defense,
sometimes incapacitation of prey

Question 9

what is the function of the lateral line?

Answer 9

• detect wave movement in the water

Question 10

what are the different functions of the anterior and posterior kidneys?

Answer 10

anterior kidney: hematopoietic; “head”

posterior kidney: excretory; “tail”

Question 11

what are the 2 types of swim bladders? how does each work?

Answer 11

1. Physostomous swim bladder: connected to the gut
   
   • connection to control the amount of gas in the swim bladder
2. Physoclistous swim bladder: NOT connected to the gut
   
   • Control the amount of gas in the swim bladder via capillary gas exchange

Question 12

What are the 2 hematopoietic organs in the fish?

Answer 12

1. Hematopoietic
2. Endocrine

Question 13

what the central lymphoid organ in the fish is?

Answer 13

thymus

Question 14

pyloric ceca

Answer 14

secrete enzymes and provide additional digestive areas to the intestine

Question 15

operculum

Answer 15

“gill cover”
- bony flap that protects the gills from harm

Question 16

hepatopancreas

Answer 16

• pancreas combined with the liver
• production of digested enzymes and absorption of digested foods

Question 17

pseudobranch

Answer 17

• gill-like structure under the dorsal operculum
• single gill arch, with a single row of gill filaments

Question 18

otolith

Answer 18

• “ear stone”
• can be used to age fish