Practical lab 4

Question 1

Phylum Chordata defining features

Answer 1

1. Nerve cord
2. Notochord
3. Presence of pharyngeal pouches
4. gland or a tissue that concentrates I2
5. post anal tail

Question 2

lateral line system

Answer 2

modified scales that run from the operculum to the tail and serve to detect vibrations of low frequency in water

Question 3

homologous features in the perches and the tetrapods

Answer 3

fins and the presence of paired appendages in tetrapods

Question 4

axial muscles

Answer 4

longitudinal axis of the body

Question 5

appendicular

Answer 5

associated with the appendicular skeleton i.e. limbs etc

Question 6

the prominent muscles in the perch ?

Answer 6

axial

Question 7

Myomere

Answer 7

zig zag patterned muscles that looks like a large W

Question 8

horizontal septum

Answer 8

Divides the myomers into the dorsal and ventral myomeres

Question 9

What is the function of the Gastrointestinal tract in perches?

Answer 9

it starts at the mouth and empties in the cloaca or the external environment via anus.

ingestion, digestion, absorption and the elimination of undigested food

Question 10

caecum

Answer 10

junction of the small and the large intestine where the food would be held and processed by the microorganisms.

Question 11

esophagus in perches

Answer 11

a short and straight tube leading from the orophraynx to the stomach

Question 12

pyloric caeca

Answer 12

found at the junction of the intestine and the stomach.

they serve as secretory and absorptive functions

Question 13

what does the length of the perch’s intestine indicate?

Answer 13

that its carnivorous and has a shorter intestine than the herbivores

Question 14

description of pancreas in perches

Answer 14

light orange diffused mass of tissue that is found along the ventral border of the intestine

Question 15

what is the main function of spleen in perches

Answer 15

production and maintenance of the blood cells

Question 16

function of kidney in chordates

Answer 16

1. eliminate nitrogenous waste
2. maintaining the salt and water levels of the body
3. maintain the pH and the sugar levels in the body

Question 17

holobranchs

Answer 17

gills with double sets of filaments

Question 18

how do perches perform gaseous exchange.

Answer 18

1. water is constantly drawn into the mouth then into the pharynx while the opercula is closed.
2. valves in the mouth are closed so the water is forced to pass through the gill rakers, then through the gill slits, over to the gill filaments and then behind the posterior free ends of the opercula which is now opened.
3. as the water passes through the gill filaments the gaseous exchange takes place.
4. counter current flow

Question 19

counter current flow

Answer 19

the arrangement of the calipers are in such a way that the blood flows in the opposite direction to the flow of water in the gills to maximize the movement of O2 in the blood

Question 20

other function of gills other than their respiratory function

Answer 20

excretory function, gills are used over kidneys

Question 21

Circulatory system in perches

Answer 21

typical low pressure single type system, only the pumping of the deoxygenated blood

Question 22

transverse septum

Answer 22

a heavy membrane separating the pericardial and the abdominal cavities

Question 23

Sinus venosus

Answer 23

1. receives blood from the common cardinal veins and hepatic sinus.
2. opens directly into the atrium

Question 24

equivalent structure to atrium in higher vertebrates

Answer 24

atria

Question 25

locomotion in rats

Answer 25

digitigrade

Question 26

Name the three salivary glands in a rat

Answer 26

1. parotid gland
2. submaxillary gland
3. sublingual gland

Question 27

Tear producing gland in rats

Answer 27

extraorbital lacrimal gland

Question 28

name the teeth that rats dont possess

Answer 28

canines and premolars

and as herbivores their teeth continue to grow throughout their life time

Question 29

viscera

Answer 29

it is found within the body cavity i.e. coelom.

the internal organs are suspended here

Question 30

pertioneum

Answer 30

membranous tissue formed from the mesoderm

Question 31

lesser omentum

Answer 31

membrane that joins the lesser curvature of the stomach to the liver

Question 32

greater omentum

Answer 32

double walled peritoneal sac which extends from the greater curvature of the stomach to the spleen

Question 33

three areas of the stomach

Answer 33

1. cardiac portion (entrance from the esophagus)
2. fundic portion
3. pyloric portion

Question 34

rugae

Answer 34

folds on the walls of the stomach

Question 35

three regions of the small intestine

Answer 35

1. duodenum - receives ducts from the digestive glands.
2. jejunum
3. ileum

Question 36

spleen

Answer 36

spleen along with liver remove old RBCs from circulation and break them down