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A modified check valve that has a screen on the suction end to prevent debris from entering the pump or pipe. If circumstances preclude finding it, then living happily without it also requires wisdom and fortitude. I have frequent urges to go but with little relief. While in ground water, MTBE persists and moves freely. Bioengineered and artificial beings have the full rights of organisms if they meet the test of being alive. The exchange process is made only for ions having the same charge.

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I am very scared. I would think it should not be any worse than I feel right now. Has anyone else had this combination surgery? What am I in for? My surgery is set for August 13th. Any pre-op hints would be greatfully appreciated. You can email me at firecopper sbcglobal. He has a large polyp which was unable to be removed via colonoscopy. They at Hopkins also found dysplasia He's meeting with the doc this week to discuss what to do next We are praying there is no cancer.

They took 10 markers to check for cancer and when the doc called him he said he wasn't sure as of yet, but is calling in an Oncolongist. Please pray and our prayers are with you all that have to go through this. I have just sent a note to Sheri Main difficulty is still not having normal bowel function Hoping time will help, along with imodium tablet once a day. I am 30 days post op from sigmoid colon resection surgery.

Doing OK overall but last few days feeling an awful lot of pain in lower abdomin by inscision. Is this normal at this time.

My scar is about 6 inches long. I have started moving more and started to work from a bit. I am worried about really pulling on something and develping a hernia in that area. Are there any tell tale signs of a hernia associated with this surgery or around the inscision? Thanks for the help: My Dr has 30 years experiance and did the operation using the large scar and staples.

I was happy with that as I am an old operating room nurse. I believe he can get a much better view through the larger opening. I did develop a paralitic ileus which took two weeks to resolve. They gave me Morphine 2 mgs for pain i had nightmares with this and asked them to cut it in half then asked them to cut it out after a week.

I think the narcotic had something to do with the ileus. I am home now and getting stronger with each day , bowel movements will probably never be the same, i use Milk of magnesia which works well. I expect to be back to normal in another month. I have had four colonoscopies in 6yrs and the latest showed up 35 polyps none were cancer. My surgeon has told me that because of the number of polyps he would do another colonoscopy in 6months which is two months from now. He has indicated if polyps are found he will do a gene test to see if the suspecting gene is activating the large number of polyps.

He has also indicated that eventually if polyps continue at this rate that it is inevitable that one would be cancerous and an operation to remove part or all of the bowel should be undertaken. Can anyone tell me if this is how things are done considering my history or are they just letting me know the worst case scenario.

I have read the article and does the information still comply, the reason why I am asking is, My Mother has recently had a resection, unfortunately didn't go according to plan, I am not sure whether her bowel was cleaned prior to surgery and she was on normal diet literally 12hrs after surgery hence she had to have emergency surgery where by she ended up with an ileostomy and in Intensive Care, also had to have a further 2 more ops including traceostomy, still there, I am a nurse and it is hard for me to understand how this happened.

Hi, Could you send me a sample diet for a recovering patient, I'll be caring for my sister who had emergency surgery in Mexico and will return next week. What should they add or delete from their previous diet. What is a normal activity level.. It has been 4 years since my Bowel Resection. I recently yesterday had a Bowel movement which contained Blue Suture material tangles with fiber. When I pulled on the suture material to get it the rest of the way out it hurt so I cut it off up as far as I could.

Can you tell me what is going on with my body. How did this material get loose about 10 inches came out and still some in there. Is there any danger of infection. I called the surgon's office but can't get into see him for a couple weeks.

Staff did not think this was serious. I am really afraid. Thanks for your help. My husband and I live in a motorhome fulltime, so we are fairly mobile! My new diagnosis is intestinal pseudo obstruction, and I have elongated and tortuous intestines per colonoscopies.

Elective resection surgery was posed to me as a possibility, and I'm intrigued by the laparoscopic approach. What source should I use to locate an experienced surgeon? We are currently in Lake Placid, Fla. Family, Please read this so you will know what I will be up against the end of January. This should answer all your questions. As a Nurse and a patient I am scheduled for a sigmoid colectomy due to perforated Diverticulitis with abscess formation in the near future ,I found your article to be informative and well written.

It is my hope that any patient who requires major surgery will empower themselves with knowledge regarding their surgical procedure. I am getting sicker as the days go on. Lots of presure and pain in my belly,back and bladder. Still have constipation so take a prescription laxative. Yesterday went to the bathroom 15 times. If I don't take the laxative I will be in pain and unable to go. Can't eat or I will get deathly sick. Going into a deep depression.

I am not the person I use to be. It has been over a year that I have been this sick. Thinking about telling them to take the rest of my Sigmoid and live with a bag! I am 53 and trying to get my New Senior Home Care business off the ground. Thought you might be interested in this. I'm sure you guys will be checking all of this out too. My son needs a bowel resection due to a perforation in his bowel and it's going into his bladder.

He has a mesh in his abdomen because he had his spleen out 9 years ago from a car accident. Will this mean that he cannont have the laproscopic surgery? My mom had bowel reef survey six months ago and has had nothing but issues with it the thing is constent tummy pain through out her tummy and know one can tell is what is wrong could the survey been done wrong.

My husband was operated on a week ago for a bowel reconnection. So far he has not passed any wind and his abdomen is very swollen and dilated and painful. What is the next treatment required? I had a sigmoid colon resection surgery on Feb.

I had a great surgeon!!! I went home 7 days later. Sore and 37 stainless staples to be removed on the 23rd of this month. I suffered with diverticula disease for years and the pain got so intense I passed out driving. I decided I had no more choice. I am thankful all turned out well. I had a regular anesthetic as well as an epidural in my back..

When you wake up you don't have to experience the pain. Nothing by both except ice chips. Then after you get the bowel sounds back and pass gas they give you clear liquid.

Then the next day or so. I am home and tolerting a regular diet. I haven't got a big appetite but need to focus on the healthy side and eat healthy when I can. If anyone needs a fantastic surgeon, I live in AZ. He is a general and vascular surgeon. Fantastic bedside manner also Hope this info helps someone.

Went into the ER nearly a month ago for diverticulitis pain - ended up one of the diverticuli was perforated, leaking infection into my stomach. IV antibiotics cleared up the infection and I was sent home with more antibiotics and pain pills, which, thank goodness, I didn't take much of. Now I am having pain again - while in the hospital a general surgeon told me I needed a resection and would be receiving a colostomy.

I've read that a "bag" is not always necessary. I'm clearly going to have to undergo the surgery in the very near future, but can't stand the thought of a colostomy and a second surgery to remove it. TANA dont worry about a "bag" i went in for resection on 27th April and came out 25th May with out bag but had problems while in hospital and since coming out only wish my doctor would have given me a bag people with bag fitted were going home after days i still off work and have been told to expect another 2 months off thats 4 month in all.

Thank you for all this insight, I have just resently been diognosed with Colon Inertia, and they are scheduling surgery the first or second week in Sept. Just wondering is someone can explain what that is, and what kind of sugery it involves. And can it possible be cancerous? Thank you for any help, Tami. I had a lower bowel resection in August because of a carcinoid tumor. Since then I have gotten sharp left side pain. It hurts to lay on my right side when I have these pains, but somewhat tolerable on the left.

Is there a serious reason for this or is it a result of the healing? Thank you in advance for your help, Linda. I had a lower bowel resection in august of this year I am having lots of bowel issues. I have frequent urges to go but with little relief. Some days okay but most not. I have developed hemroids also with some bleeding. Does this ever get better? Jean, An epidural would not be appropriate for a procedure to that extent however I would ask about a spinal block, similar to an epidural but the medications are administered into two different locations.

Epidural is only administered into the dura mater of the spine and the spinal block is administered in the subarachnoid space; allowing the medication to get into the CSF. Epidural is nice for a woman in labor but thats about it, a spinal provides loss of sensation to the entire body below the diaphragm.

I really hope this helps but I am not an anesthesiologist or a doctor just a surgical technologist in training. I had my sigmoid removed due to severe diverticulitis and now I keep going to the bathroom.

How long does it usually take to get back to normal? Dr did Follow-up CT Scan.. Everything Good He says Patience? I am going in feb 6th for my second resection. My first was in I did not listen to doctors advice and quit taking my medication for Crohns disease after first surgery because i felt great. Now i wish that i would have. I was in the hospital for 31 days with the first one, complications. This one is scaring me because all i have to go by is what happened the first time.

My doc is a great doc and told me that he has never lost a patient from this surgery and i am not going to be his first.

Hope all goes well. I was in a car accident when i was 9 years old and suffered from seatbelt injuries which resolted in a bowel resection where they removed over 12 inches of my large intestine. I was becoming to be back to normal around a month after my wreck and have been in fine health since. I had twin daughters and had a c sec something i thought my prior surgery would interfere with but all went well and am pregnant with number 3 and planning oon another c section.

My Grandmother is in terrible pain from a gas build up in her stomach, she is not able to relieve the pressure through her stoma. She has lived with the bag for most of her life and has not had this problem before.

The bouts come almost every day, sometimes twice a day and last for some hours, it is excruciating for her and very distressing for the family. The doctors have ruled out a hernia or any form of blockage, and advise nothing more than strong painkillers. I read above that sipping peppermint essesence in hot water and eating natural yoghurt can help, has anybody tried these remedies?

I had a bowel resection from diverticulies in November of I also have a transplanted Liver and Kidney in I too have had bowel movement problems since , some before but much worst since. My problem is I have diarreah also every day, and it starts around midnight and goes all night until about 6 or 7 in the morning. I am talking 3 fiber pills every day 1 in the morning and 2 in the evening. Doesn't help much, can anyone tell me why this only happens int night and not in the day.

They thought it was what I was eating but it doesn't seem that it only one kind of food. Any advice will be greatly appreciated. I have a simnoid colon resection in August of 9 CM removed.

Since then I have been in and out of the hospital because of severe bloating and pain, however every test run shows absolutely no problems. Most days I have bowel movements in excess of 5 with no true pattern. One may be diarhea, the other solid, one soft, etc. I feel like it is wasting the time of many going to the hospital so much, but am clueless to what is going on, Any suggestions.

My diet is watched closely, etc. I had to have a temp. It has healed nicely, however I have these 2 pones on either side of my incision middle. Is this fat or could it be scar tissue. Two years ago I was dianosed with a large tumor. They removed about 12 inches of my colon as well as my cicum. I take one diarrhea daily.

Sometimes it works and sometimes it does not. Is there any other medications I can take that is better for my system? What are some foods that would be good for me? To Mike, Jimmy and Pat. I also had a colon resection done cancerous polyp in September of Everything that you have described is probably what most people experience. My first year was extremely frustrating, but it does get better.

I have tried many ntural remedies and my chiropractor advised me to be sure and take probiotics the refrigerated ones found at nutrional stores and an enzyme for digestion. Ijust bought some fennel tea which aids in digestion and gas, etc and will let you know how that works. What I have found out with my diet, is the best thing to do is not eat too much of a variety of foods at one time.

I love vegtables, fruits, etc but they dont always digest well. Also, eat small amounts of the foods you like and that helps me alot. Walking and excersize helps. It is extremely frustrating at times, but don;t give up too soon. My next step is to go see a dietician for further help. If any of you wish to e-mail me, my e-mail address is lindaflanigan live. We have to be there for moral support, beleive me!!!

PS I go see Dr every 6 mos now for my blood work. Good luck to all of you, and if you have any of your own suggestions, please pass them along.

I had right hemi colectomy six months ago and yes I had trouble with diarhhea. It eventually turned out I had become extremely lactose intollerant and still cant each raw vegetables like salad. So it may be you need to adjust your diet. Keep a diary, remove some foods and see what happens. I had a Right hemi colectomy 6 weeks ago because i had a very large pre-cancerous polyp, i was 27 years old at the time which is extremely rare, and am lucky to be alive. I was distended and in horrible pain for 10 days, in hospital for My bowels began to work again on their own, peppermint tea helped allot and moving around in bed, feels like it will never end but does.

I also had an Ileus, which resulted in me having a gastric tube placed down my nose into my stomach to drain the bile from my stomach, it was the worst ten days of my life bar none, i couldn't eat until day These symptoms a rare but thought people should know what can occur.

I have a massive scar which has only just healed, still have muscle pain around the abdomen. I had a bowel resection in Aug due to diverticulitus and then had to have a tidy up in January due to scar tissue and the reconnection not being the best. Before I had the resection, I had lost a load of weight and was in fact under weight, but since my last operation I have gained fat around the laporoscopy area which is very uncomfortable. I eat sensibly and actively exercise, but nothing will shift this great lump from my stomach.

Like others, I suffer with loose stools, persistent wind and quite frequent diarehoea. My stomach problem is affecting not only my ability to buy clothes, but is VERY uncomfortable when doing yoga and pilates.

I am a 46 year old woman who on August 6th had a complete hysterectomy and bowel resection. I had a mass of endometriosis on my rectum, so that is why I had to have the resection. I had an ileostomy for almost 3 months, so the resection could heal I had the ileostomy take down 3 weeks ago.

Still am afraid to leave the house for more than 20 minutes. If I make a quick run, I make sure I put on an adult brief. I can hardly make it to the bathroom. How long before this gets better? Is there anyone else out there who had this kind of trouble for endometriosis. Please let me know. Hello, The article is very good. Just I want to point to some rare indications for partial or total colectomy that were not mentioned in the article but I have met in many references , they are pseudomembranous colitis that can not be controlled by chemotherpeutics , chronic dys-functional colitis , and ischaemic bowel diseases which is common only in very old patients.

Thank you for this article. I have recently undergone my 4th operation for chrons related symptoms, 2 resections approx 8 strictures, my recent surgery went well but i am now concerned because my surgeon has called me up and wants to speak to me ASAP regarding results they have from the damaged bowl. I am dreading the consultation as I fear the worst ie cancer.

My point, I have not found any articles that prepare you for this situation post op, ie what happens after the operation what gets tested and why? Anyways I had a look at the percentages regarding colorectal cancer and this is encouraging so thank you for providing this information.

I know this may not be the results that are given but I fear the worst, I suppose it's in some of our worst fears that get confirmed that gives me great concern. I have been dealing with IBSC for over a decade now; I was put on Amitiza and worked my way up to the maximum dose allowed with no relief. I have had a colonoscopy and am on my 2nd Sitz-Marker test. I am now taking a cocktail of OTC constipation remedies that help a little but, Heaven forbid, should I skip even one of them; this cocktail consists of 75 - mg of sennosides, 1T Citrucel and 17g of Miralax..

I am currenty consulting with a surgeon as I am considering colectomy. I have found very little reference as to the long term results of a colectomy for constipation. I am actually considering just a partial colectomy as my colon is not damaged or diseased My surgeon warned me of loose stools and bowel incontinence after the surgery; but, he is also only thinking of a total colectomy. Any information, suggestions or experiences would be greatly appreciated.

In I was rushed to Emergency 3 times due to abdominal pain. It was discovered after much prompting on my part to my doctors that I had Cecum Bascule. I had 2 feet of my large colon removed along with my cecum. This disorder creates multiple polyps and research indicates they do not discover this disorder until autopsy from death by Colon Cancer. Since that time I was diagnosed with Diabetes. I have chronic diarrhea and any change of diet has no affect. As time passes, the diarrhea gets worse and at this point feel like I have Crohns because I can't be far from the bathroom as when I have to go, I have to go now.

In addition, I cannot find much information because this is so rare. When you are going to have a resection, make sure you get the facts about not just the after care but the long term care.

My husband has a fistula related to melanoma cancer connecting his intestine to his colon. He will be having a double bowel resection to remove the fistula. Does it get better? He currently has diarrhea times a day with no relief from immodium. I had abowel resection Feb. My life has not been the same since. I really would like to have someone to talk too. I can not be away from a bathroom and most days I do not feel well at all. I have no control of my bowel movements,i still where adult diapers.

My email is kittyzabroski yahoo. Ihad the resection because of scar tissue. And the gas never in my life I had a partial resection of my colon in following severe bleeding after a colonoscopy. I was on warfarin because of a prosthetic aortic valve.

Initially, I was under the impression that very little was left of my colon 4 or 5 inches. The surgeon could not identify which polyp removal site was causing the bleed so he had to remove most of it. During subsequent colonoscopies my colon appears to be getting longer. Either the orignal estimate was wrong or my colon is growing. I am age I also have Marfans syndrome. In I was diagnosed with acromagely.

I have had surgery for both conditions. I had the tumor on my pituitary removed, but my growth hormones IGF1 continue to be outside the normal range. Could the excess growth hormones cause my colon to grow, or should I consider that initial estimate in to have been an error? Jack 65 I think the original estimate was off. The colon is 5 feet. The polyps can be removed without removing any of the colon. I've been through 4 surgeries just found out looking at a 3 resection and 6 polyp removals.

My 85 year old mother was diagnosed with diverticulitis in the sigmoid section of her colon in August. She had a 10cm abscess which was drained and 2 drains were inserted, one in the abdomen, the other in her bottom.

She is still complaining of nausea but no pain. The doctors want to do the resection but at her age, I'm afraid she shouldn't have this surgery. She is in a skilled care facility and I feel as long as they can control her other complaints, why put her through such an extensive surgery? Her quality of life is better now that she is going through rehab and other therapies for other reasons but this is too much for a woman her age.

Ultimately, it is her decision but I am trying to give her information on exactly what she will face during and especially after. They have already said she will have a colostomy, this means yet another surgery to have it reversed. She's not in the best of health as it is and was resigned to enter the facility voluntarily after she could no longer care for herself at her home safely after numerous falls and calls to for help to get up either off the floor or out of the recliner she spent the night in because she couldn't get up.

At her age, I really don't think this type of surgery will prolong her quality of life and may hasten her demise if infection or complications set in. I had sigmoid colon resection 4 months ago. I was able to avoid a bag. I had drainage for 2 mos. When the drainage stopped I felt good having normal bowel movements for maybe the first time in my life. I had chronic diverticulitus for years and it finally perforated my colon.

This past week I started to have pain in area of colon and skin around incision. I went to ER running a temp. My surgeon lanced the area of incision that was last to close and drained a lot of reddish fluid. I left the hospital yesterday after a 48 hr.

I am home again with dressings to change along with packing and the oral antibiotics. My question are these; 1 How concerned should I be about reoccurring infection at this point? I've had several and removed polyps before but don't remember ever hearing they were precancerous. Should I get a colonoscopy sooner? Hy recent surgeon says "I don't need to worry about diet anymore but try not to over do carbs. What are your thoughts about those two things?

I want to be as proactive as possible and certainly want to avoid any reoccurring infection and or diverticulitus even though the 8" section removed was the area with the problematic area with the bend removed. Let me know what you think, thank you. I had chronic diverticulitis. I initially had bleeding for three days after surgery and ended up having to have a blood transfusion. Could not eat for a few days without throwing up plus had no appetite anyway so was put on IV nutrition.

The doc said mine was a complex case. The diseased section was low in the sigmoid colon - 10 inches was cut out. I was in the hospital for 7 days. I am in third week of recovery at home and doing great for the most part. I try not to just sit or lay down most of day. I get up and move around often and try to do very light housework. Following recovery directions to the T about food and everything else.

Still have the occasional aches in stomach area, more good days than so-so days. No loose stools but have had feeling of constipation two times in three weeks. Once, I waited and it resolved on its own time schedule - I was expecting to go when I felt that feeling that I needed to go but body had it's own time schedule. The other time I took a small dose of Milk of Mag. Drinking lots of water per directions and I am not normally a big water drinker.

Despite those first days after surgery and a blood transfusion, I have no regrets getting this operation done. My life will be so much better now - no more chronic diverticulitis, no taking strong dual antibiotics for two -three weeks at a time to treat infections, E.

Dealt with that on and off for 10 years! Operation was suggested five years ago and I refused to do it - it sounded too scary. Last episode of diverticulitis convinced me that I just couldn't tolerate the pain and risks anymore. I think taking the refrigerated probiotic capsules twice a day during recovery have helped digestive system tremendously.

Six days postoperative bowel resection readmission with gastric problems then developed femoral thrombus. Had emergency surgery December 15 for diverticulitis with fistulas needed a bag which was a night mare.

I am recovering from re-connective surgery April 23 still a little sore. A large incision from under breast to almost vaginal area and of course where the stoma was. I am so happy not to have the bag and with a great surgical team I would recommend the surgery.

My wife had 8 inches of her colon removed 2 months ago. After 2 weeks went by she had a hard time breathing dizzy when she gets up no energy at all. She has a hard time even trying to take a shower. She said it feels very tight in her chest has 0 energy.

Does anyone no if anyone has had this Issue after colon resection. My concern is that now my abdomen stays distended with a large buldge on the left side of left upper abdomen. When I eat, the buldge becomes larger along with abdomen also becomes larger for quite some time and does not seem to be resolved. Has no relation as to bowel movements. I had a post op illeus after I was sent home 5 days postop and returned for another 7 days. Was wandering if the illeus could have caused problems with healing of surgical area.

Im not a surgeon, but was wandering if anyone would know if the peritoneum is suppose to be closed before the incision and could this be the reason? Also the xray on in the ER for illeus revealed some ascites. Would this be a concern following this type of such a surgery and the reason behind the abdominal distention? If any one has answers please email me at: I just had bowl resection surgery. It went very well , hospital stay 6 days, had drain tube, ng tube, after surgery.

They give you pain pump. I was dreading the drain tube removal and it was nothing! Cutting the stitches hurt more than taking it out! I'm very sore , but on my way to recovery! Don't be scared of the surgery! Good luck and God bless you. I had a transverse colon resection 6 months ago due to a motor vehicle accident trauma, part of the colon was removed However, on a given day I may have several diarrhea stools along constipated stools I have kept a diary to no avail Have severe pain one day ok the next after eating exactly the same food at the same time.

Its difficult to plan outings cause I don't know what "today " will be like. Always have to be near a bathroom And bless the person in the next stall Its embarrassing, but what can one do? Sometimes I feel I have to explain why. My family and friends tell me its ok to have these problems as its better than the alternative Its hard to have to live life this way..

My son is in the hospital now and has not been diagnosed with FAP or anything but they are going to run some test on him Monday. He is 8 years old and has had stomach problems all his life.

He has been hospitalized numerous times for being impacted. Today he passed a few white lumps that looks like fatty tissue and was round looking. And from to they have done colonoscopy and came back good but have not done one since I took a picture of it and googled it and with the photo the results came back it resembles anal cancer.

But this has not been confirmed by test yet. A second opinion would greatly appreciated. My mother just had surgery. Her surgery went well thank god. She's had a few complications though like a lot of nausea. And she mentions having a lot of discomfort in her rectom and gets very nauseas when she drinks sprite. If anybody has any of these issues and knows If this is normal please let me know pesmi64 gmail. I had a colon resection 2 months ago by keyhole surgery.

I now have a burning sensation pain to the left of my tummy button where they put the camera in and removed the diseased bowel. I was in hospital with the pain yesterday. They checked me out and said it may well be Neuropathic pain. I only have the pain when i stand up and walk around for a few minutes.

Any suggestion of how i can treat this? I have a few days off work before I have to go back. I await your reply and thank you in advance. Hi i am 42 years old male and had a lower anterior resection due to stage 0 colon cancer. They removed about 10 inches of my sigmoid colon. I continue to take 1 teaspoon of Metamucil in the evening but continue to have erratic bowels 5 to 9 on different days and difficult to evacuate never feeling empty.

After these episodes I'm exhausted and want to just lay down. Anyone post 1 year with same residuals? Please reach me by email with colon cancer as subject. Hi I had 13in of sigmoid colon removed. I was told I could eat anything after surgery. The classic view of an open circulatory system is based on the image of pseudocoelomic or coelomic fluid bathing the tissues directly; this fluid is circulated throughout the coelom via the actions of the body wall musculature and animal movements.

These vessels end abruptly where their contents move into the coelom or other large space where gas, nutrient, and waste exchange take place directly between the cells tissues and hemolymph or lymph—at this point the fluid could be described as extracellular fluid. Hemolymph then moves through venous sinuses or simply through the coelom and into a pericardial sinus, through cardiac ostia and into the heart for recirculation.

Indeed both of these views are technically correct, yet convey the idea of a primitive, poorly designed and regulated cardiovascular system that is unable to sustain higher metabolic demands Figure 1 a. Looking at the issue from the other side, our standard view of a closed circulatory system is based on a system where a multichambered muscular heart pumps blood through parallel systemic and pulmonary circuits simultaneously Figure 1 c.

Blood is pumped into major elastic arteries the aorta and large arteries , which then flows into medium and small smooth muscle-based vessels and then into arterioles, which supply the capillary circulation. At the capillary level, gas, nutrient, and waste exchange take place between blood and tissues across an endothelial layer. Venous blood then returns to the heart via, venules, small and medium veins, and finally back into the heart via the vena cava.

In the closed circulatory system at no point does the blood leave the confines of the vascular endothelia and as such there is a clear distinction between blood and lymph [ 1 — 3 ]. An exhaustive phylogenetic review of cardiovascular morphologies is not necessary to make this point clear.

A few well-described examples from specific taxa can be used to illustrate the complexity of the issue and dramatically point out the shortcomings of the existing definitions.

Members of the phyla Annelida contain some of the most complex examples of worm-like invertebrates [ 5 — 7 ]. The segmented annelids have evolved several mechanisms in order to enhance convective transport between internal compartments.

The most primitive of these being the development of a coelom and coelomic circulation followed by the development of intracellular iron-based oxygen binding pigments hemoglobins , and the most advanced being a fairly well-developed blood-vascular system [ 8 , 9 ]. While there are many anatomical variations observed in the cardiovascular system of annelids that appear to have evolved due to activity patterns, feeding behaviors and environment, some of the most complex systems are seen in the class Polychaeta.

The general pattern of circulation in polycheate worms starts with a dorsal vessel that runs just above the digestive tract Figure 3. Blood flows anteriorly where the dorsal vessel anastomes with a ventral vessel either directly or by several parallel connecting vessels. The ventral vessel runs under the digestive tract and carries blood posteriorly.

Each segment of the animal receives a pair of parapodial blood vessels that arise from the ventral vessel. The segmental parapodial vessels supply the parapodia, the body wall integument , and the nephridia and give rise to intestinal vessels that supply the gut. Blood moves from the ventral vessel through the parapodial system and returns to the dorsal vessel through a corresponding segmental pair of dorsal parapodial vessels Figure 3.

When gills are present and integrated with the blood vascular system as opposed to being perfused with coelomic fluid they contain both afferent and efferent vessels Ruppert and Barnes Pressures are generated by peristaltic waves of contractions through the dorsal vessels. These blood vessels and their associated blood sinuses do not contain an endothelium but are lined by only the basal lamina of overlying cells Figure 3 Brusca and Brusca The molluscan cardiovascular system has evolved extensive vascular networks with efficient centralized pumps e.

The functional significance of these complex vessels is seen in the highly active Cephalopod Molluscs, which show the most extensive evolution and specialization of the cardiovascular system Figure 4.

Blood is driven at high pressures by the heart through a cell-lined closed circulatory system complex circulatory system that is able to sustain metabolic rates almost equivalent to some vertebrates [ 13 , 14 ]. To sustain such high oxygen uptake rates, paired branchial hearts have evolved to pump venous blood through the gills, after which the arterial blood flows to the ventricle where it is pumped to the systemic circuit. Functionally, the cephalopods have evolved a multichambered heart capable of maintaining separation between venous and arterial blood and regulating branchial and systemic circulations.

Additionally, this group of animals has developed the cardio-respiratory regulatory mechanisms needed to integrate cardiovascular and ventilatory performance with metabolic demands [ 15 ]. The anatomical complexity of the cardiovascular system, along with the development of capillary-like exchange vessels, an endothelia-like vascular lining and the appropriate regulatory mechanisms appears to have been selected for in this group by increased activity patterns associated with predatory behavior, swimming, and jet propulsion [ 12 , 13 ].

While the cardiovascular systems of these more active cephalopods are quite robust and seem to exhibit convergent evolution with some vertebrates, in terms of their vascular complexity, there is a great deal of discrepancy in reports as to the nature of the endothelia-like lining of the vessels and the degree to which tissues are perfused. This leads to the question: It can be hypothesized that the invertebrate vascular lining has evolved for reasons more to do with hemodynamics and maintaining laminar flow, than the array of functions ascribed to the vertebrate vascular endothelia.

The evolutionary origin of the invertebrate vascular system and its lining are derived from the coelom, yet few invertebrate taxa exhibit a vascular endothelium [ 20 ]. Laminar flow is required to minimize the energy needed to move blood through these complex vascular systems. However, if there are sudden variations in vessel diameter or irregularities in the vessels walls turbulent flow can result.

In turbulent flow a significantly greater pressure is required to move a fluid through the vessels as compared to laminar flow. This is best exemplified by the fact that in turbulent flow the pressure drop is approximately proportional to the square of the flow rate as opposed to laminar flow where the pressure drop is proportional to the first power of the flow rate [ 21 , 22 ].

It would require a robust heart and would be energetically inefficient to move blood in a turbulent pattern through a vasculature that changes shape abruptly and where the interiors of the vessels are not smooth as is seen in many lacunar systems.

Thus to minimize the energy required to move blood through the cephalopod circulatory system it would be advantageous to evolve mechanisms to facilitate laminar flow and one of which could be the development of an endothelia-like lining [ 23 ].

While there is relatively little variation within closed systems, the same cannot be said of open systems, which appear to vary greatly in complexity from a simple globular pump with no specialized vessels to a more-or-less complete circulatory system. The circulatory systems of all vertebrates are completely lined by an endothelial cell layer as opposed to the invertebrates, cephalochordates, and tunicates.

The vertebrate endothelium is defined as being a continuous sheet of mesodermally derived cells lining the vasculature and in a broader context even more widely distributed throughout the body are highly active with multiple functions and are heterogeneous in structure and function [ 24 ]. Functionally and most simply, the endothelium serves as a selective barrier separating the blood from the tissues i. A more modern and comprehensive view of endothelial function would include significant roles in hemodynamics, hemostasis, vasomotor tone, growth, and proliferation of other cells, antigen presentation, and metabolism of tissue or blood derived hormones [ 25 ].

For the purposes of this discussion, a functional barrier separating circulating blood from the tissues defines a closed circulatory system and as such can be considered the primary function of the endothelia or the cell-lined vasculature. Unlike closed systems where blood and lymph are functionally separated by the endothelium, in truly open systems these two fluids are considered to mix freely and are thus termed hemolymph blood and lymph.

However, the presence or absence of hemolymph does not explicitly define a system as open or closed as comparative physiologists also define hemolymph based on the absence of defined cell lineages red cells, thrombocytes, and leukocytes. Thus, one may have a cell-lined circulatory system that meets the definition of being closed yet contains hemolymph as seen to varying degrees in the cephalopods and crustaceans [ 4 ].

The definition of open versus closed is therefore based upon histological endothelium and cellular hemolymph terms rather than in physiological terms functional.

Although there are more species of insects than any other group in the world and more individual nematodes, crustaceans exhibit a greater variation in form and diversity than any other animal phylum [ 28 ]. The decapod crustaceans have colonized a wide range of environments from the deep sea through the intertidal zone, and onto land.

During the evolution of the invertebrates a number of key adaptations were responsible for their radiation. In crustaceans, the evolution of a segmental arterial system was a singular event that made the unique adaptive radiation of this group possible and the evolutionary innovation that allowed members of this group to become large and highly mobile [ 29 ]. Historically, the crustacean circulatory system has been considered open.

However, during the past two decades our knowledge of the decapod crustacean circulatory system has increased substantially [ 26 , 27 , 29 — 32 ].

The muscular ventricle is housed inside a primer chamber, the pericardial sinus. Heart rate and stroke volume can be controlled independently via nervous input from the cardiac ganglion and CNS or by direct actions of neurohormones on the cardiac muscle [ 29 , 32 ].

Submersible Pumps