Excretory System Flashcards
Human Systems Unit
what is the purpose of the skin in the excretory system?
the sweat glands secrete perspiration, which is water, salt, and urea.
**the main purpose of sweating is temperature regulation, not to excrete wastes.
what is the purpose of the liver in the excretory system?
excretes bile that is created when hemoglobin is broken down.
The MAIN PURPOSE of the liver in this system is to filter out the urea and uric acid from the blood.
define DEAMINATION
removal of an amino acid group from an organic compound
ex. amino acids, nucleic acids
how is urea formed?
ammonia, which is extremely toxic, is produced from deamination and is combined to form urea.
how is uric acid formed?
uric acid is formed when the liver breaks down nucleic acids.
What is the purpose of the lungs in the excretory system?
their job is to remove carbon dioxide(CO2) from the body.
what is the urinary system?
the main system that excretes waste from our body.
what does the word renal refer to?
the KIDNEYS
what is the function of the kidneys?
the kidneys produce urine, which contains nitrous wastes like urea and uric acid.
what are the 3 regions of the kidney?
Renal CORTEX- outer layer made of connective tissue
Renal MEDULLA- middle layer
Renal PELVIS- central collecting space where urine drains into.
How do the kidneys work?
The kidneys, each the size of a fist located on either side of the spine below the diaphragm. They are fed by the renal artery that branches off the aorta, and they have a renal vein that leaves the kidneys and enters the inferior vena cava. Each kidney is made up of millions of nephrons where the urine is produced.
define URETERS
the muscular tubes that carry urine from the kidneys to the bladder.
how does urine move through the ureters?
through peristalsis
define BLADDER
a hollow muscular organ that expands as urine enters
define URETHRA
carries urine from the bladder to the external opening. Longer in males than females
What are all the parts of the excretory system?
Renal artery, renal vein, kidneys, aorta, inferior vena cava, ureters, bladder, urethra
define NEPHRON and explain how they work
the functional unit of the kidney. Each nephron is fed by a small afferent arteriole that branches off the renal artery. These arterioles then branch into a capillary bed, which is called the glomerulus. The glomerulus is surrounded by a funnel-like part of the nephron and this is called the bomans capsule. The capsule then tapers into a small thin tubule called the proximal tubule. Urine is carried from the proximal tubule into the Loop of Henle, then through the distal tubule, and then into the collecting ducts which collect the urine from many nephrons and drain into the ureters.
AFFERENT vs EFFERENT
afferent- going in (before glomerulus)
efferent- going out (after glomerulus)
What are the 3 parts of urine formation?
FILTRATION- glomerulus/bowman’s capsule
REABSORBTION- proximal tubule/loop of Henle
SECRETION- distal tubule
How does filtration work in urine formation?
The glomerulus acts like a high-pressure filter. Water and dissolved solutes pass through, but things like proteins, blood cells, and platelets are too big to pass through so they stay in the blood.
How does reabsorption work during urine formation?
Reabsorption occurs through both active and passive transport. Sodium ions are actively transported out of the cell, and since they are negatively charged all the positively charged ions transport out of the cell as well. Water follows this now because of osmotic force, the concentration is now higher on the outside of the tubules than inside the tubules. As the water leaves, the urine then becomes more concentrated and all that’s left is the waste that we call urine.
how does the loop of Henle and the proximal tubule get its energy to actively transport substances?
there are many mitochondria in the nephron to provide this energy.
how does secretion work in the urine formation process?
secretion is the movement of a substance from the blood into the nephron. Ammonia, excess hydrogen ions, and potassium ions all get moved into the blood due to active transport.
DIURETIC
something that increases your urine output.
ex. caffeine
