Kidney - Definition, Function and its Structure - Pathskill

 Kidney

The kidneys are very important organs found not only in humans but also many other animals and each person contains two identical and symmetrical kidneys so the function of the kidney we're going to focus on in the next hour Electra's the kidneys basically function in not only in excretion but also in controlling and regulating the osmolarity of our blood plasma now in this lecture we're going to focus on the basic anatomy and structure of the kidney so let's begin by taking across-section of any one of our kidneys

                  we basically obtain the following diagram so we slice our kidney and this is what it looks like so notice that we have many of these individual sections and structures found inside our kidney and this is what we're going to focus on in this lecture so on this side of the kidney we have the renal vein shown in blue we have the renal arteries shown in red and we have the ureter shown in green on the other side we have the renal capsule the renal cortex the renal medulla our renal pelvis the renal pyramids which are these brown sections here and we have the nephron shown in purple now this diagram only shows a single nephron but actually we have over a million nephrons within this single kidney and the nephron is the basic unit of structure of the kidney and we'll discuss what the structure of the nephron is in just a moment first let's discuss the renal capsule the renal cortex and the renal medulla now the renal capsule is a very thin membrane it's essentially a transparent fibrous membrane that encloses and surrounds the entire kidney it's found on this outermost portion here now the purpose of the renal capsule is twofold it basically serves as a protective layer it protects the kidney from being damaged and it also gives our kidney it's be like shape now the structure the section of the kidney right below the renal capsule is known as the renal cortex 

it basically begins right below the capsule and ends right about here so this entire section here is our renal cortex now the renal cortex is the uppermost section if we don't consider the capsule and it also contains several important structures of the nephron so it basically contains something called the Bowman's capsule and the glomerulus it also contains the proximal and the distal convoluted tubules and we'll see what that is in just a moment now if we move to right below the renal cortex we have a section known as the renal medulla the real medulla is basically this entire section here that consists of these renal pyramids and the renal pyramids exist as a result of the stacking of these nephrons they basically are stacked adjacent to on another along the entire section of the medulla as well as the cortex and they form these renal pyramids

                so the real medulla is the inner portion of the kidney and it basically contains several important structures of the nephron just like the cortex does the medulla contains a structure known as the loop of Henle it also contains the Veii Cerreta which is a bed of capillaries as we'll see in just a moment and it contains our collecting duct so now that we discussed these three structures we are ready to define what a nephron actually looks like so the nephron if we take the nephron shown in purple we zoom in on the nephron and we place it right side up so we flip it this way we basically get the following diagram so let's begin with this section here found in the cortex known as the Bowman's capsule so this entire section here is the Bowman's capsule it kind of looks like a claw now the Bowman's capsule inside this Bowman's capsule enclosed inside is a capillary it is a a bed of capillaries and this bed of capillaries is known as our glomerulus so as we'll see in just a moment the renal artery divides and subdivides into many tiny blood vessels known as the a faring arterioles and they bring the blood blood of the blood plasma into this bed of capillaries known as our glomerulus now connected to the Bowman's capsule is a section of a of the tube known as the proximal convoluted two next is our descending and ascending loop of Henle followed by the distal convoluted tubule and finally our collecting duct now notice that this dashed line separates the renal cortex

this section here from the real medulla which is this section here now so this is the cortex this is our medulla so inside the cortex we have the Bowman's capsule as well as our glomerulus we also have the proximal convoluted tubule as well as the distal convoluted tubule now inside the medulla we have the descending and the a sending loop of Henle we also have the collecting duct and we have a second capillary bed

system known as the basic art of the base erecta so the vase erecta is basically this entire bed of capillaries and we'll discuss what the function of that is in just a moment so let's discuss what the renal pelvis is the renal pelvis is this entire section here it's basically a funnel shaped cavity

that collects the urine that is produced by the individual nephrons and it directs that urine into a structureknown as our your reader there your readers a structure that moves urine from the kidney and into the urinary bladder where it is stored before we secrete that too outside of our body now let'smove on to our renal artery so basically the renal artery is the blood vessel system that brings the oxygenated blood the blood filled with nutrients and also filled with the waste products that must be secreted by that kidney so the renal artery delivers oxygenated blood to the kidneys and it splits and it subdivides into these very tiny blood vessels known as a very arterioles and these are the blood vessels that bring the blood the oxygenated blood to each one of these nephrons found along the entire medulla and cortex of the kidney so if this is our nephron this is our a ferret arteriole that is ultimately that ultimately comes from the renal artery

so it brings that blood plasma hydrostatic hydrostatic pressure pushes Some of that blood plasma including our

excretory waste products from this glomerulus into the Bowman's capsule and eventually through this entire system

into the collecting duct and then into the ureter into the bladder and eventually outside of our body now this blood vessel is also an oxygenated blood vessel but it is known as the efferent arteriole so we have the a Ferren and the efferent arteriole and this brings our oxygenated blood to a second system of capillaries known as the de Cerreta

so basically this set of capillaries brings the oxygen blood the nutrients to the cells found in this section and then it empties out that deoxygenated blood to this entire vein system that basically connects and eventually enters and becomes the renal vein so the arena

are the renal vein receives the deoxygenated blood from the kidneys specifically from the Vasa recta of our nephron of each one of thesenephrons found inside the kidneys so it returns that deoxy a blood back to the systemic blood circulation system and will define what systemic blood circulation system is when we'll discuss the cardiovascular system and the heart so basically this is the basic structure of our kidney the kidney consists of these basic units known as nephrons that are found throughout the cortex and throughout our medulla