Chapter 9.1 Flashcards
What do waste products do to cells?
Change the balance of volume of water and the concentration and composition of dissolved substances in the body’s fluids
What is the basic function of the excretory system?
Regulate the volume and composition of body fluids by removing wastes and returning needed substances to the body for reuse
What is waste in metabolic terms?
Any substance that is produced by the body and present in excess of the body’s needs
What are examples of waste products produced by the body?
Carbon Dioxide Water Sodium ions Chloride ions Hydrogen ion
Which waste products pose a larger threat?
Nitrogenous (nitrogen containing) products like ammonia, urea, and uric acid
What happens after the body produces ammonia?
Since ammonia is highly toxic, it is converted to a less toxic compound, urea in the liver
What makes up the majority of nitrogenous waste in the body?
Urea
How much urea is eliminated in urine?
About 50%
What is excretion?
The process of separating wastes from the body fluids and eliminating them
Which body systems perform excretion?
The respiratory system
The Skin
The digestive system
How does the respiratory system perform excretion?
It excretes carbon dioxide and small amounts of other gases, including water vapor
How does the skin perform excretion?
It excretes water, salts, and some urea in perspiration
How does the digestive system perform excretion?
It excretes water, salts, lipids, and a variety of other pigments and chemicals
How are most metabolic wastes excreted?
They are dissolved or suspended in solution and are excreted by the excretory system (aka the urinary system)
Where are kidneys located?
The lower back on each side of the spine
What are kidneys surrounded by?
A large cushion of fat
What does the cushion of fat do for the kidneys?
Offers some protection
What can happen if a person loses a kidney?
The other kidney increases in size to handle the increased workload
What do kidneys release urine into?
2 muscular 28-cm-long tubes called ureters
Where does urine go from ureters?
It is moved down by peristaltic actions of the muscle tissue to the muscular urinary bladder where it is temporarily stored
What is drainage from the bladder controlled by?
2 rings of muscles called sphincters that can relax so urine can drain from the bladder
What is the innermost sphincter controlled by?
It is involuntary controlled by the brain
What does urine exit the body from?
It exits through a tube called the urethra
How large is the urethra in males?
Approximately 20 cm long and merges with the vas deferens of the reproductive tracts
How large is the urethra in females?
About 4 cm long
What does each ureter open into?
It flares open to form a tunnel-like structure called the renal pelvis
What does the renal pelvis have?
Cup like extensions that receive urine from the renal tissue
What is the renal tissue divided into?
2 sections: Outer Renal Cortex and Inner Renal Medulla
What are the 3 main sections of the kidney?
Renal cortex, Renal Medulla, and Renal Pelvis
What is embedded in the renal cortex and extends into the renal medulla?
A million microscopic structures called Nephrons
What are Nephrons responsible for?
Filtering various substances from blood and transforming it into urine
What is each nephron organized into?
3 main regions: A filter, a tube, and a duct
What are the 3 main structures of a nephron?
Filter
Tubule
Duct
What is a Bowman’s capsule?
The filtration structure at the top of each nephron
What happens within each Bowman’s capsule?
A renal artery enters and splits into fine network of capillaries called glomerous
What are glomerulus?
The network of capillaries that soul off from the renal artery within the Bowman’s capsule
What does the glomerulus do?
The glomerulus acts as a filtration device
What remain in the blood after reaching the glomerulus?
Proteins
Large molecules
Red blood cells
This is because the glomerulus is impermeable to these
What passes through the walls of the glomerulus?
Water, small molecules, ions and urea
Where do the parts filtered from the glomerulus go?
It proceeds into the Bowman’s capsule of the nephron
What is filtrate?
The substances that are filtered out of the blood and proceed to the Bowman’s capsule
What is the Bowman’s capsule connected to?
A long tubule that is twisted back on itself to form a loop
What are the 3 sections of the loop called?
The proximal Tubule
The loop of Henle
The Distal Tubule
What does the tubule do?
The Tubule absorbs substances that are useful to the body, such as glucose and a variety of ions, from the filtrate passing through it
What does the tubule empty into?
A large pipeline channel called a collecting duct
What does the collecting duct do?
Functions as a water conservation device and reclaims water from the filtrate passing through it
What is the filtrate that remains after passing through the collecting duct?
A suspension of water and various solutes and particles called urine
What does the renal vein do?
Takes in the solutes and and water reclaimed during reabsorption
