Number of gut openings and blood systems

Question 1

what does the number of gut openings mean

Answer 1

The number of gut openings simply refers to a digestive system with amouthand ananus.

Question 2

how does this number vary

Answer 2

• Suppose a digestive system hastwo openings, one for ingesting food (eating) and another for egesting food (getting rid of waste). In that case, the number of openings will betwoand we call a gut such as this athrough gut.
• If a digestive system has onlyone opening, the same opening for both ingesting food and egesting waste, the number of openings will beoneand we call a gut such as this ablind gut.

Question 3

what are these systems

Answer 3

Athrough gutand ablind gutare both examples of atrue gut. A true gut refers to a system where internal digestion occurs.Diploblastic and triploblastic animals have a cavity inside the body called thealimentary canalorgut. This is where food is digested by enzymes and absorbed. Not all diploblastic and triploblastic animals, however, have a through gut.

Question 4

what is a through gut

Answer 4

Athrough gutis acomplex,true gutand an example of acomplete digestive system. A complete digestive system has a mouth opening at one end and an anus at the other. Food passes in onlyone directionin the system and exits at a different opening than the one through which it enters.

Question 5

what is a blind gut

Answer 5

Ablind gutis abasic(more primitive)true gutand an example of anincomplete digestive system.This means that a single opening serves as both a mouth and anus. Food and waste move through a single opening.

Question 6

what are the disadvantages of a blind gut

Answer 6

• Egested wastes, called faeces, will mix with the new food being taken in
• One space has to carry out all the different functions and cannot work efficiently

Question 7

what are the advantages of through gut

Answer 7

• The faeces are released away from the new food being taken in
• The gut can have different regions that have different functions for digesting and absorbing food

Question 8

what is a blood system

Answer 8

The circulatory system (the system that pumps blood through a body) varies from simple systems in invertebrates to more complex systems in vertebrates.

Question 9

what is a closed circulatory system

Answer 9

Closed circulatory systemsare a characteristic ofvertebrates. However, there are significant differences in the heart structure and the circulation of blood between the different vertebrate groups. Thiscirculatory system is a network ofvessels(arteries, veins and capillaries) and apump(the heart).In higher-order organisms, this is a closed-loop system. In other words, the blood circulates through the body while remainingin the blood vessels. Smaller, microscopic vessels called capillaries allow for diffusion between the blood and surrounding tissue.

Question 10

what is an open circulatory system

Answer 10

In contrast to a closed system, lower-order organisms have anopen circulatory system. The blood isnot enclosed in any blood vesselsin an open circulatory system but is pumped into ahemocoelcavity. A hemocoel cavity is a simple form of a coelom. The blood is calledhemolymphbecause it mixes with theinterstitial fluid. The heartbeat of the organism relies on the muscle movement of the organism. As the organism moves, the heart will beat. If the organism remains stationary, the heartbeat will stop. The hemolymph surrounds and bathes the organs within the hemocoel. The basic movement of the animal allows for both gaseous and nutrient exchange.