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The Kidney



Abdominal cavity: The space within the abdomen where the organs are located.
Arteries: Blood vessels that carry oxygenated blood away from the heart.
Cardiac output: The amount of blood pumped by the heart per minute.
Creatinine: A waste product produced by the muscles that is filtered by the kidneys and excreted in urine.
Diabetes: A group of diseases characterized by high blood sugar levels.
Filtration: The process of separating solids from liquids or gases.
Fluid balance: The state of equilibrium or stability in the body's fluid levels.
Glomerulus: A tiny blood vessel cluster in the kidney where filtration of blood occurs.
Glucose: A type of sugar that serves as a primary source of energy for the body.
Insulin: A hormone produced by the pancreas that regulates blood sugar levels.
Lifestyle factors: Factors related to a person's daily habits and choices.
Nephrons: Each of the functional units in the kidney responsible for filtering the blood and producing urine.
Nonspecific: Not specific or particular.
Pancreas: An organ in the body that produces insulin and helps with digestion.
Physiology: The study of how the body and its parts function.
Proteins: Large molecules made up of amino acids that perform various functions in the body.
Reabsorption: The process of absorbing or taking back in.
Renal pelvis: The inner part of the kidney where urine collects before it passes into the ureter.
Skeletal muscle cells: Muscle cells attached to the bones that help with movement.
Ureter: A tube that carries urine from the kidney to the bladder.
Vertebrates: Animals with a backbone or spinal column.



The kidneys are two bean-shaped organs found on the left and right sides of the body in vertebrates. Kidneys filter the blood in order to make urine, to release and retain water, and to remove waste. Each kidney feeds urine into the bladder by means of a tube known as the ureter.

Kidneys also regulate fluid balance and blood pressure. They are also responsible for the reabsorption of water. In humans, the kidneys are located high in rear of the abdominal cavity, one on each side of the spine. Despite their relatively small size, the kidneys receive approximately 20% of the cardiac output.

Many of the kidney's functions are accomplished by relatively simple mechanisms of filtration, reabsorption, and secretion. Filtration is the process by which cells and large proteins are filtered from the blood to make an initial step in the process that creates urine. The kidney generates 180 liters (1.06 quarts = 1 liter) of filtrate a day, while reabsorbing a large percentage, allowing for the generation of
only approximately 2 liters of urine.


African Americans are more at risk for kidney failure than any other race. More than 1 in 3 kidney failure patients living in the United States is African-American.

Diabetes is the #1 cause of kidney failure. Diabetes is a group of diseases in which there are high blood sugar levels over a prolonged period. Diabetes is due to either the body not producing enough insulin (in the pancreas) or the body not responding properly to the insulin produced. Insulin regulates the body’s process of turning food, especially, glucose (sugar), from the blood into fat, liver and skeletal muscle

About 1 in 9 African-American adults has diabetes. About 1 in 3 African-Americans with diabetes does not know he or she has it. African-Americans with diabetes develop kidney failure more often than whites. Diabetes causes nearly 40 percent of all cases of kidney failure in the United States.



Former NBA player forced to retire

Sean Elliott

kidney transplant recipient

          Former NBA player forced to retire           Alonzo Mourning

kidney transplant recipient


Tracy Morgan

kidney transplant recipient



waiting for a kidney transplant


Nick Cannon

suffers from kidney disease

image 1.png

Former NBA All-Star

Current G League CEO

kidney transplant recipient


Three Time NBA Dunk Champion

Currently (2023) seeking

Kidney transplant



Stevie Wonder

kidney transplant recipient



Selena Gomez

kidney transplant recipient


George Lopez

transplant recipient

See, you don’t have to be black to have kidney problems.

High blood pressure is the #2 cause of kidney failure. It causes about 1 out of 4 cases (25%) in the United States. High blood pressure is a long term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. About 90–95% of cases are primary, defined as high blood pressure due to nonspecific lifestyle and genetic factors. Lifestyle factors that increase the risk include excess salt, excess body weight, smoking, and alcohol.

Almost half (over 42%) of African-American adults have high blood pressure. African-Americans are six times more likely to get kidney failure from their high blood pressure than whites.


Almost 1 in 5 African-Americans is uninsured. As a result, their health care choices may be limited.


Calculations of kidney performance are an important part of physiology and can be estimated.

STEM Topic 10: Problem Set
  1. If the number of nephrons (each of the functional units in the kidney) in a human kidney is represented by N, and there are 750 nephrons in each kidney, what is the total number of nephrons in two kidneys?

  2. The average adult human kidney is about 10 centimeters long. If each dimension (height, width and depth a kidney is doubled, how much larger is the volume?

  3. The renal artery supplies about 20% of the cardiac output to the kidneys. If the total cardiac output is 5 liters per minute, how much blood is supplied to the kidneys per minute?

  4. The renal pelvis of a kidney can hold about 10 milliliters of urine. If a person's kidneys are filled to 80% capacity, how much urine is present in the renal pelvis?

  5. The glomerulus, a part of the kidney, filters about 180 liters of blood per day. How much blood does the glomerulus filter in one hour?

  6. A doctor orders a urine sample to be collected over a 24-hour period. If the patient collects 300 milliliters of urine in 12 hours, how much more urine should they collect in the next 12 hours to complete the 24-hour sample?

  7. The concentration of creatinine in the blood is measured in milligrams per deciliter (mg/dL). If a person's blood test shows a creatinine level of 1.2 mg/dL, how many milligrams of creatinine are present in 1 liter of blood?

  8. The blood flow rate through a renal artery is given by the equation R = 2A + 10, where R represents the blood flow rate in milliliters per minute and A represents the cross-sectional area of the artery in square millimeters. If the cross-sectional area is 15 square millimeters, what is the blood flow rate?

  9. The volume of urine produced by the kidneys can be calculated using the equation V = 0.03T + 0.5, where V represents the volume of urine in liters and T represents the time in hours. If a person urinates several times over a 5 hour period, what is the volume of urine produced?

  10. The concentration of sodium (Na) in the urine can be estimated using the equation C = 0.5(Na) + 20, where C represents the concentration of sodium in per liter and S represents the sodium concentration in the blood . If the sodium concentration in the blood is 140 mmol/L, what is the estimated concentration of sodium (NA) in the urine?

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