Excretory System

Dialysis Patient Symptoms Blood pressure abnormally high 190/110 mmHg Tired, headache, nausea Decrease in urine output Blood test showed high levels of creatine Treatment Dyalysis 3 times a week 3-4 hours each time Change his diet to reduce the amount of salt intake Kidney transplant

Blood Components RBC’s (Erythrocytes) – transport Oxygen and Carbon Dioxide Plasma – transports Nutrients and Waste WBC’s – immune cells Platelets – helps heal cuts

Important Points Excretory system: eliminates nonsolid wastes through exhalation, sweat, and urine Main parts: Lungs Skin Urinary System

Lungs Removes excess (extra) carbon dioxide from the blood We then breathe it out Keeps a balance of oxygen and carbon dioxide in our body

Skin Sweat glands release excess water and salt through skin pores Sweat also cools the body to maintain homeostasis

Kidney Removes waste from the blood, “cleans” the blood Controls the amount of water content in the blood Maintains a balanced pH in the blood 3 Step Process: Filtration, Reabsorption, Excretion

Nephron

Filtration, Reabsorption, Excretion

Filtration, Reabsorption, Excretion Blood enters kidney through renal artery. Blood then enters through a network of capillaries known as the glomerulus of each nephron. Filtration

Filtration, Reabsorption, Excretion During Reapsorption the materials in the filtrate that the body needs are reabsorbed into the bloodstream. Reabsorption of glucose, amino acids, vitamins, and ions involve active transport from the filtrate back to the blood. The amount of water reabsorbed depends on the amount of water in the blood. If the amount of water in the blood is low, water is quickly reabsorbed. If water is not low it stays in the filtrate. What are some instances when water would be low in the blood? Reabsorption

Filtration, Reabsorption, Excretion During excretion the non- reabsorbed filtrate is now called urine and it continues to move within the nephron in the collecting duct. Excretion

Excretory (Urinary) System Kidneys: filters that take the waste out of the blood and make urine Ureters: tubes that carry the urine to the bladder Bladder: a bag that collects urine Urethra: a tube that carries the urine out of the body http://kidshealth.org/kid/htbw/

Homeostasis The circulatory, respiratory and excretory system all work together to maintain homeostasis in the body. They are responsible for the distribution of oxygen and nutrients to the body and the removal of carbon dioxide and metabolic wastes from the body. They seem to work automatically, however they are all under the control of the nervous system.

Renal Artery: Blood enters the kidneys here Glomerulus: capillary network, main FILTER of the nephron. High pressure causes materials to diffuse out of the blood here. FILTRATION Loop of Henle: U-shaped tubule surrounded by capillaries, materials in the filtrate that the body needs are diffused back into the blood here. REABSORPTION Collecting Duct/Tubule: Liquid and waste not absorbed by the blood enter here, called Urine, which contains water, salts, glucose, amino acids, urea, vitamins, and ions. EXCRETION

Ureters: tubes that carry the urine to the bladder Urinary Bladder: a bag that collects the urine Urethra: a tube that carries the urine out of the body

Video

The functional unit of the kidney that filters the blood of excess waste products and water is the --. Nephron Ureter Loop of Henle Collecting tubule Urine is excreted through a pathway in the following order – Kidney, ureter, urethra, urinary bladder Kidney, ureter, urinary bladder, urethra Ureter, kidney, urinary bladder, urethra Urethra, ureter, urinary bladder, kidney 2. Filtration, reabsorption, and excretion are three steps that occur in the – Nephron, glomerulus, ureter Ureter, urinary bladder, urethra Glomerulus, loop of Henle, collecting tubule Kidney, heart, lungs

Kidney Facts The kidneys represent only 0.5% of the total weight of the body, but receive 20-25% of the total arterial blood pumped by the heart. The rate of filtration is approximately 125 ml/min. or 45 gallons (180 liters) per day. Considering you have 7 to 8 liters of blood in your body, this means that your entire blood volume gets filtered approximately 20-25 times a day. Each kidney contains over a million nephrons The right kidney is slightly lower than the left Each kidney weighs about 113-170 grams and is about 11.4 cm long and 6 cm wide and 2.5 cm thick. The first workable artificial kidney was developed during World War II in 1944 by Dr. William Kolff who was living in Holland. According to the National Kidney Foundation, more than 370,000 Americans are being treated with dialysis or kidney transplantation for kidney failure. Nearly 12 million Americans may be at risk for chronic kidney disease. The use of a dialysis machine is suggested when a patient’s blood urea nitrogen value exceeds 100 mg/dl (the normal value is 30 mg/dl)

Kidney Stones