Lecture 19- Fish characteristics 3

Question 1

how many chambers does a fish have?

Answer 1

2 chambered heart. (atrium and ventricle)

Question 2

describe the blood flow through the fish heart

Answer 2

venous blood enters the sinus venosus from the curverian duct which collects blood from the body via several veins and arteries. Blood then enters the atrium and is pumped to the ventricle which pumps the blood out of the heart to the gills where gases are exchanged

Question 3

blood leaving the heart goes through what?

Answer 3

bulbous arteriosus which dampens/evens the pressure oscillations

Question 4

why is blood pressure in fish low?

Answer 4

because blood has to slowly flow through tiny vessels of the gill to capture oxygen from dense water. If blood pressure rises too high fish can bleed from their gills. Their lamella would rupture.

Question 5

low blood pressure limits what?

Answer 5

the ability of the circulatory systems to supply tissue

Question 6

explain counter current exchange and why it works for fish… draw a diagram

Answer 6

counter current exchange in fish works because water drawn in for respiration flows in the opposite direction to the blood flow of the gills. Because the oxygen level in water is always hgiher than the oxygen level in the blood insuring efficient diffusion

Question 7

describe lungfish heart

Answer 7

lung fish can live in water with little or no oxygen becayse they possess gills and lungs! Lungfish have partially divided hearts. The right side receives oxygenated blood from the lungs, whereas the left side receives deoxygenated blood from the tissues. Blood stays seperated through the ventricle

Question 8

describe lung fish circulation

Answer 8

oxygenated blood passes the gills to the dorsal aorta and the rest of the body. Deoxygenated blood goes through the gills and lungs. Based on oxygen supply the pulmonary vasomotor segment can shunt blood as needed. If the body is low on oxygen blood in shunted from the gill to the lungs instead of into the dorsal aorta. However, if the waterbody is high in oxygen the blood can go from the gills directly to the dorsal aorta

Question 9

draw a diagram illustrating circulation in a lungfish

Answer 9

Question 10

what is a key role the kidneys play in fish?

Answer 10

balancing salt and water levels

Question 11

what are the different kind of sex fish have?

Answer 11

1. ) most fish are dioecious (seperate genders)
2. ) some are hermaphroditic (monoecious; both functional testies and ovaries in the same individual)
3. ) other are all female and reproduce by parthenogensis