Flashcards in Renal System Deck (64)
What makes up the renal System?
What are the function of the kidneys?
Maintaining homeostasis within the internal environment, by regulation of the volume and composition of body fluids
What is the definition fo homeostasis?
The ability or tendency of a living organism, cell or group to keep the conditions inside it the same despite any changes in the conditions around it, or this state of internal balance.
What are the key functions of the kidneys?
elimination, regulation and secretion
What other functions do the kidneys have?
red blood cells
What is renin?
An important enzyme in the control of blood pressure
What is erythropoietin?
a hormone that stimulates the production of red blood cells
Where are the kidneys?
They are on the posterior wall of the abdominal cavity: one on each side of the vertebral column at the level of thoracic and lumbar vertebrae
How much of the cardiac output do the kidneys get?
What sits on the top of each kidney?
an adrenal gland
How big is a kidney?
weighs about 100-120g each
What is the structure of a kidney?
an outer fibrous capsule, surrounding the kidney
Where do they kidneys get their blood supply?
The blood supply is from the aorta via the renal artery and returns to the vena cava via the renal vein
What are the two layers of the kidneys?
The outer reddish brown cortex which has a rich blood supply and the inner medulla where the functional units of the kidneys are found (the nephrons)
What is the hilum?
It's an opening on the concave side (facing medially). The renal artery, renal vein, nerve supply and lymphatics enter and leave via the hilum,
What is the medulla?
The inner region of the kidney that is divided into approximately 12 pyramids, containing bundles of tubules.
Describe the tubules?
Tubules appear as lines ( medulla rays) each pyramid with overlying cortex' forms a renal lobs
Where do the pyramids empty?
The tip of each pyramid empties into a calyx (singular), and calicies (plural) empty into the renal pelvis
How is urine carried?
Urine is carried from the renal pelvis to the urinary bladder via the ureter
What is a nephron?
It's the basic functional unit of the kidney. More than 1 million nephrons per kidney.
Describe a nephron?
Approx 3cm long. A tubule that is closed at one end and open into a collecting duct at the other end. Starts as a knot of capillaries called glomerulus. Surrounded by the glomerular capsule which attaches to a tubule. the tubule has a winding twisted portion (proximal convoluted tubule), a loop (loop of Henle) and a distal convoluted tubule
Describe the blood supply to the nephron?
It has a blood supply from a branch of the renal artery, the afferent arteriole. Blood is collected from the efferent arteriole.
Goes in thorough the afferent arteriole and out through the efferent arteriole
How come there is pressure in the glomerulus?
The fact that the afferent arteriole has a wider bore than the efferent arteriole . This therefore forces out the filtrate of the capillaries into the capsule
What is the glomerular body?
the glomerulus and capsule
substances with small molecular size are filtered out into the cup surrounding the glomerulus
what is the juxtaglomerular apparatus?
A microscopic structure in the kidney that regulates the function of each nephron and secretion of renin
What is passive transport?
filtration: the process whereby fluids pass through a falter
Diffusion: ions or molecules from an area of higher concentration to an area of lower concentration
Osmosis: movement of fluid through a semipermeable membrane from a solution with a low solute concentration to a higher solute concentration
What are the 3 stages of the renal system?
A passive process which takes place in the semipermeable walls of the glomerulus. Water and small molecules are forced out of the glomerular capillaries, through the filter and into the Bowman's capsule to form 'glomerular filtrate'
What happens to larger molecules during filtration?
Blood components which are large molecules (blood cells, platelets and plasma proteins) are usually retained in the blood (they are too large to get out). The kidneys form about 180 litres of dilute filtrate per day. Most os selectively reabsorbed, producing a final urine volume of approx 1.5 litres per day