Crayfish Digestion System Essay

After the food particles travel down the digestive tract, the waste gets released through the anus, which is “located on the ventral surface of the terminal appendage. The first and second pairs of legs are used in the organisms' filter feeding, ensuring that particles too large to handle are kept out while the other sets of legs create the stream of water rushing into the organism,” (Daphnia). 8. Describe the type of nervous

Crayfish are decapods pertaining to the phylum arthropoda, which are invertebrates and contain an open-circulatory system.1 The system works by the hemolymph getting re-oxygenated in the gills before being transporting to the heart by brachio-cardiac veins and then pumped to sinuses that bathe tissues with oxygenated hemolymph.2 The crayfish contain a neurogenic heart that depends on neuronal input from cardiac ganglion.3 The neurogenic heart requires nerve impulses to produce contractions in contrast to a myogenic heart that can contract independently from the nervous system.3 The crayfish heart will beat due to the reaction of the ganglion to stimuli in the environment.4 Stimuli will affect the autonomic nervous system in the crayfish that control involuntary actions such as the heart rhythm.4 Neurotransmitters are the chemical signals in which the nervous system regulates both heart rate and contraction.3The autonomic nervous system breaks into two categories as parasympathetic system that is involved in relaxation of organs and the sympathetic system that will stimulate increased activity. Neurotransmitters can either increase or decrease heart rate by altering the patterns in neural activity of the heart.4 Crayfish are poikilotherms, which means they cannot metabolically thermoregulate thus conform to the ambient temperature in the water.

Adaption 1 Tracheae: an insects tracheae is a complex network of tubes that delivers oxygen-containing air to every cell of the body Cuticle: in particular an outer layer of living tissue Mayfly nymph adaptation An adaptation that mayfly nymphs need most to survive in the water is having gills. On a mayfly nymph there are four to nine pairs of gills that are located on each side of their abdomen. These gills are leaf-like in shape and constantly keep moving back and forward. This beating motion increases the amount of water that goes through the nymphs gills. The gills create currents of water that bring in a fresh oxygen supply.

In the caecum, where most of the absorption happens, food is sorted into fluids and particles. Nutrients absorbed from here are dispersed throughout the body through blood. Indigestible food move on the next stage. Remainings go through the intestine and further digestion and absorption takes place. Then the undigested food then exits through the anus.

The blood finally pumps back to the atrium where the process begins again. (University of Waikato) (See fig.5 ) In humans, blood enters the heart from the posterior and anterior veins vena cava which carries de-oxygenated blood from parts of the body into the right atrium. From the right atrium the blood flows into the right ventricle and through the tricuspid valve which shuts when the ventricle is full. The blood exits the heart through the pulmonic valve, into the pulmonary artery and then into the lungs where gas exchange occurs.

The adaptive features of animals: i. Adaptation to live in the habitat lack of oxygen A. Crayfish: Crayfish lives in fresh water stream, which is an aquatic environment. The oxygen level in fresh water upper stream is higher than the lower stream, but the oxygen concentration is still low. The gills of crayfish are much bigger than the size at first glance. They occupied under the cephalothorax carapace in branched-shape and provided a large surface area to volume ratio to carry out gas exchange. Fresh water will be pulled into the cavity by the movement of the “gill bailers”.

Digested molecules of food, as well as water and minerals from the diet, are absorbed from the cavity of the upper small intestine. Most absorbed materials cross the mucosa into the blood and are carried off in the bloodstream to other parts of the body for storage or further chemical change. As already noted, this part of the process varies with different types of nutrients. 5. 2) Page B13, and #1-4 1.

Cryptosporidiosis is a form of gastroenteritis that is caused by the parasite Cryptosporidium. Once the parasites are taken in by mouth, Cryptosporidiosis can occur. [1] Outbreaks of cryptosporidiosis have been linked with public swimming pools and contaminated water supplies. Cryptosporidium is a type of protozoa, and infects humans through ingestion of their cysts on hands, water or foods that have been contaminated with faecal matter. Once in the human body the cysts are activated by the acid in the stomach which leads to excystment in the small intestine.

The digestive system is located around the stomach area. Along with the digestive system, many other organ systems all work together to create an organism. An example of this would be if a person eats a sandwich and then goes for a run. During the run, the circulatory system helps the body breathe, the muscle system helps the bones move, and all the while the digestive system digests the food. Later on, the excretory system gets rid of the waste, or food that the body can’t use for nourishment.

The process of peristalsis starts in the oesophagus when a bolus of food is gulp down. The food is brought to the stomach by the strong wave-like motions of the smooth muscle in the oesophagus, where it is churned into a liquid compositioncalled chyme. The process of peristalsis proceeds in the small intestine where it blends the chyme byits to and fro motion and here nutrients are absorbed into the bloodstream through the small intestine walls. Peristalsis ended in the large intestine where water is absorbed into the bloodstreamfrom the undigested food constituent. Finally, the residual waste products are expelled from the body through the rectum and anus.

These structures beat to produce a constant current of water, allowing particles to be filtered by fine setae on the thoracic legs. The particles are then transferred to their mouth groove to be ingested. D. magna typically feed on planktonic algae (Ebert, 2005). The following experiment uses algae to test what affects the feeding rate of D. magna. The rate of filtration

Gastric bypass surgery shrinks the size the stomach to limit the amount of food that can be eaten. The most common type in the U.S. is the Roux-en-Y gastric bypass. Surgeons make a small incision through which to access the stomach. A small pouch is created by either banding or stapling part of the stomach. A Y-shaped section of the small intestine is connected to the pouch that allows food to bypass part of the digestive system so that fewer calories and nutrients are absorbed.

Unit 5 Anatomy and Physiology for Health and Social Care P4 Explain the physiology of two named body systems in relation to energy metabolism in the body The two body systems selected in relation to energy metabolism in the body are the digestive system and cardiovascular system. The digestive system breaks down foods and the cardiovascular system enables absorption and usage of the food. The term energy metabolism in the body relates to chemical reactions that that maintain cells and organisms. It is divided into two categories: catabolism is the breakdown of molecules to obtain energy and anabolism the synthesis of all compounds needed by the cells.

Introduction: Dissections are performed on preserved animals donated specifically for science education in order to provide a hands-on experience to observe and study anatomy of an animal in three dimension, unlike a textbook, and how the organ systems are interconnected. In this particular dissection a fetal pig was used because the organs present in a pig, and their position in the body are similar to those of humans which provides insight on how human organs systems work overall and why they are essential to life. The purpose of our experiment was to focus on the external, digestive, cardiovascular, respiratory, and excretory systems of the fetal pig to understand how theses system work together in order to sustain life. Materials & Procedure: