Trout+dissection


 * [[image:http://aquaticpath.phhp.ufl.edu/lesionguide/images/rainbow%20trout-web.jpg width="789" height="242"]]
 * Objective: **

.- To study the external and internal anatomy of a trout.

**Material:**

.- Scissors

.- Tweezers

.- A trout

.- Dissecting tray

**Background:**

The trout has a bony skeleton, so it belongs to **the bony fish.**

**External Anatomy**

1.- Place the specimen in a dissection tray.

2.- Note the general regions of the fish:

2.1.- The **head** :

Look at the **fish´s mouth:**

What are its **teeth** like?_

What is its **tongue** like?

.- At the side of the head, there is a **hard flap** to protect the gills. This is called the **operculum or gill covering.**

Used the tweezers to lift up the operculum and look at the **gills. The gills have a lot of __blood vessels__ that allow gas exchange (oxygen and CO2) between the water and the fish.**

**.-** What is the colour of the gills?

Push a **stick** into the mouth of the fish and observe how the operculum moves. This is what happens when a fish inhales water to breathe.

2.2.- The **trunk** region, which terminates at the **anus**.

.- What is the body covered with?

.- What does the surface of the body feel like? Is it **rough or smooth**?.- Identify the different types of fins:

**Dorsal fin (**has spiny rays),**Pectoral fins,Pelvic fins,Anal fin,Caudal fin** (propulsion mechanism of the animal)

.- How many **fins** does the **fish** have in total?_

.- The thin **lateral line** located to the mid-lateral area of the body extends from the operculum to the caudal fin. What does it serve?__

2.3.- **The tail**..- Draw the **caudal fin:**

After studying the external anatomy, remove a **scale** from the body and examine it under the microscope.

Draw what you observe through the microscope:

**Internal anatomy**

.-With the **scissors,** cut a large section out of the body beginning at the posterior edge of the last gill following the lateral line towards the anus.

.- Lif out this this large section of flesh and bone and view the following structures:

**.- The swim bladder ( a sac of gas).** In life the air bladder would be inflated but it will likely be collapsed in this specimen

.- Dorsal to the air bladder is the dark colored **kidney.**

.- The **heart** is near the gills.

.- The **liver** is a big gland near the heart.

.- The **sexual organs (ovaries or testicles)** are located below the swim bladder. ||  ||
 * [[image:trucha.jpg width="800" height="402"]] ||  ||