Nitrogenous wastes
Filtered in our urine.
Nitrogenous wastes found in urine as waste products
Functions of the kidney
How Kidneys Produce Urine
• Blood enters the kidneys through the right and left renal arteries
• Arterioles carry blood to the capillaries
• Glomeruli filter the blood
Glomerulus and glomerular / Bowman capsule
• Blood passes through the glomeruli
• Glomerular (Bowman)
capsule surrounds each glomerulus
• Renal tubule is attached to each Bowman capsule
Glomerulus
Network or collection of capillaries.
Three Steps in the Formation of Urine
• Glomerular filtration (water, sugar, wastes, salts)
• Tubular reabsorption (water, sugar, some salts)
• Tubular secretion (acids, potassium, and drugs)
How Kidneys Produce Urine (Cont’d)
• The glomerulus and a renal tubule combine to form a unit called a nephron.
How Kidneys Produce Urine (cont’d)
Process of forming and expelling urine
Note: Bloodstream to the renal tubule is secretion of acids, potassium, & drugs. From the renal tubule to the bloodstream is reabsorption of water, sugar, and salts.
Arteriole
Small artery
Calyx or calix
Cuplike collecting region of the renal pelvis; the term comes from the Greek, kalux, meaning a cup or case surrounding a flower bud
Catheter
Tube for injecting or removing fluids.
Cortex
Outer region of an organ.
Creatinine
Nitrogenous waste excreted in urine.
Electrolyte
Chemical element that carries an electrical charge when dissolved in water.
Erythropoietin (EPO)
Hormone secreted by the kidney to stimulate production of red blood cells by bone marrow;
-poietin means a substance that forms.
Filtration
Process whereby some substances pass through a filter.
Glomerular capsule
Enclosing structure surrounding each
glomerulus; also called Bowman capsule.
Glomerulus
Tiny ball of capillaries in the kidney.
Hilum
Depression in the part of an organ where blood vessels and nerves enter and leave; comes from the Latin meaning a small thing.
Kidney
One of two bean-shaped organs that filter nitrogepous waste from the bloodstream to form urine.
Meatus
Opening or canal.
Medulla
Inner region of an organ; the term comes from the Latin, medulla, meaning marrow.