10.1/10.2/10.3 Flashcards
Excretion
The process of separating wastes from body fluids and eliminating them from the body.
Body Systems that Perform Excretion
Respiratory-carbon dioxide
Skin-water, salts, urea
Digestive-water, salts, lipids
Excretory System
The system that regulates the volume and composition of body fluids by excreting metabolic wastes and recycling some substances for reuse.
Organs of the Excretory System
Kidneys, Ureters, Bladder, Urethra
Urine
In the kidneys, filtrate of the nephron upon leaving the collecting duct, exits the body through the urethra.
Functions of the Excretory System
1) Excretion of Metabolic Wastes
2) Maintenance of Water-Salt Balance
3) Maintenance of Acid-Base Balance
4) Secretion of Hormones
Excretion of Metabolic Wastes
- notably nitrogenous (nitrogen-containing) wastes
- eg. ammonia, urea, uric acid
Maintenance of Water-Salt Balance
- by regulating salts in the blood, the kidneys are involved in regulating blood pressure
- maintain appropriate levels of potassium, bicarbonate, and calcium in the blood
Maintenance of Acid-Base Balance
-maintain blood pH at about 7.4 by excreting hydrogen ions and reabsorbing bicarbonate ions
Secretion of Hormones
-secrete calcitriol (active form of vitamin D and erythropoietin (stimulates red blood cell production)
Kidneys
One of a pair of organs that filters waste from the blood (which is excreted in urine) and adjusts the concentrations of salts in the blood.
Ureter
A pair of muscular tubes that carry urine from the kidneys to the bladder.
Urinary Bladder
Organ where urine is stored before being discharged by way of the urethra.
How is drainage from the bladder controlled?
Sphincters
- innermost sphincter is involuntarily controlled by brain
- learn how to voluntarily control relaxation of the other sphincter
Urethra
The tube through which urine exits the bladder and the body.
Renal Cortex
Outer Layer of Kidney
Renal Medulla
Inner Layer Containing Cone-Shaped Tissue Masses
Renal Pelvis
Central Space, or Cavity, that is Continuous With the Ureter
Renal Artery
Blood vessel that originates from the aorta and delivers blood to the kidneys; splits into a fine network of capillaries (the glomerulus) within the Bowman’s capsule of the nephron.
Renal Vein
Blood vessel that drains from the kidney; returns to the body the solutes and water reabsorbed by the kidney.
Nephron
Microscopic tube-like filtration unit found in the kidneys that filters and reabsorbs various substances from the blood; produces urine.
Three Main Regions of a Nephron
Filter, Tubule, Collecting Duct
Filter
- filtration structure is the Bowman’s capsule
- renal artery enters and splits into network of capillaries called glomerulus which acts as a filtration device
- water, small molecules, ions and urea pass through walls and proceed further into nephron
- new substance is called filtrate
Bowman’s Capsule
The cap-like formation at the top of each nephron that serves as a filtration structure; surrounds the glomerulus.