Secrete water -> dissolved in water is sodium chloride, latic acid, urea
Located in lower layers of the skin, a duct carries sweat to hair follicle or skin surface where it opens at a pore.Cells surrounding the gland can contract and squeeze sweat to skins surface
1. Uses enzymes to remove the amino group (NH2) from the amino acids
2. Converts the amino group to ammonia (NH3)
3. Converts ammonia to urea, which is eliminated from the body in urine
4. Converts the remaining part of the amino acid, which is mainly carbon and hydrogen, into a carbohydrate that can be readily broken down by the cells to release energy + carbondioxide + water
Normal urine is a solution of water with dissolved wastes, such as urea and creatine, and ions such as sodium, chloride and potassium, as well as low levels of other solutes
A healthy adult produces about 1.5 L of urine a day, but this varies
The liver processes chemicals into a safer form (amonia -> urea through deamination).
Liver also:
Detoxifies alcohol and drugs
Deactivates hormones -> coverts into a form that can be excreted by the liver
Breaks down haemoglobin from dead redblood cells -> produces bilepigments -> goes into faeces
Skin
Provides a protective covering over the surface of the body and regulates body temperature.
Lungs
Involved in the excretion of the carbondioxide that is produced by cells during cellular respiration
Kidney
Located in the abdomen, each is approximately 11cm long. Each kidney is enclosed by the renalcapsule, under this is the outer renalcortex then the inner renalmedulla. The medulla consists of lots of renal pyramids (tooth) and are separated by renal columns where blood vessels lie. Then the renal pelvis funnels urine into the ureter and the renal helium is where vessels enter and leave.
Nephrons
Responsible for removing wastes from the blood and regulating blood composition. Blood enters the nephron through the afferentarteriole, it is then filtered in the glomerulus, a network of capillaries and then exits via the efferentarteriole.
Glomerular filtration
Happens in the renal corpsucle (bowmanscapsule) blood enters through the afferentarteriole which has a wide diameter and exits through the efferentarteriole which has a small diameter, this increases the resistance in flow of blood which creates very high pressure in the glomerulus. This forces blood components through differentially permeable membrane into the capsule. The glomerularcapillaries are one cell thick and the capsule wall is one cell thick, which makes diffusion easy.
What is in filtrate
The fluid that is absorbed into the glomerulus is called filtrate, it contains water, salts, amino acids, fatty acids, glucose, ureacreatine and ions.
Reabsorption
Some components of the filtrate that are of use to the body and are selectively reabsorbed back into the blood. It is carried out by cells in renaltubule, materials reabsorbed are water, glucose, amino acids and ions such as sodium, potassium, calcium. A large surfacearea is required for reabsorption, this is achieved by 2 sets of convolutions + the loop of Henle + number of nephrons in each kidney. Depending on bodies water requirements more or less water will reabsorbed or excreted. This is an active process which is under hormone control.
Tubular secretion
Adds materials to the filtratefrom the blood because too much has been reabsorbed. Includes materials such as potassium and hydrogen ions, creatine, and drugs (penacillin). It can be active or passive and maintains blood pH (7.4-7.5) and urine pH (6)
Kidney Stones
Are formed from solidcrystals that buildup inside the kidneys, usually when urine becomes too concentrated. Small crystals may pass unnoticed or crystals can combine to form stones. Large stones can get stuck in the ureter, bladder or urethra, causing intense pain, and may need to be brokenup with sound waves or physically removed during surgery.
Kidney Failure
Affects glomeruli which affects kidneys ability to filter blood.Proteins and redblood cells may leave blood at glomerulus and can be passed as urine ->blood in urine. Too much losss of protein in urine cause fluid to build up in hands + feet -> swelling. When the kidneys lose ability to excrete waste + control fluid levels = kidney failure.
Lifestyle measure to maintain kidney health
Regulate diet + maintain heathly weight
Don't smoke= smokers 3 times more likely to have impairedkidney function
Drink water
Consumer alcohol in moderation
Don't do drugs
Dialysis
Method to remove wastes from kidneys when failure occurs. Two types:
Peritoneal dialysis
Haemodialysis
Peritoneal dialysis
The peritoneum is a membrane that lines the abdominal cavity and covers organs (stomach, liver), has a richblood supply. Peritoneal dialysis uses this membrane to remove wastes. A catheter is placed in the wall of the abdominal cavity, and fluid is passed through. It contains glucose and other substances similar to those in blood, but there are no wastes in the fluid. Because of the concentrationdifference wastes will diffuse out of the blood into the fluid and useful substances will stay in the blood. After time fluid is drained out, this is usually done once a day.
Haemodialysis
Involves passing blood through an artificial kidney or dialysis machine. Blood passes through thousands of tiny tubes made of differentiallypermeable membrane and immersed in fluid. The concentrations of substances in fluid are similar to those in blood without waste. Because of concentrationdifference wastes will diffusefrom blood into the fluid. Usually takes 4-5 hours x3 a week
Liver disease
Occurs when liver is not able to process toxins for elimination. Caused by infection, genetic disorders, autoimmune problems, cancer, and lifestyle factors (excessive alcohol + fatty diet)