Kidney anatomy

Summary

This educational video delves into the anatomy of the kidneys, focusing on their structures and location within the body. Positioned between T12 and L3, the kidneys are retroperitoneal, with the right kidney slightly lower due to liver pressure. The video highlights the kidneys' relationship with surrounding organs like the spleen and adrenal glands, and explains their blood supply via renal arteries and veins. It also explores the internal structure, including the cortex, medulla, and nephrons, emphasizing how these components contribute to the kidney's function in filtering blood and producing urine.

Takeaways

• 🧠 The video discusses the anatomy of the kidney, focusing on its structure rather than its physiology.
• 📍 Kidneys are located posteriorly between the levels of T12 and L3 vertebrae, with the right kidney slightly lower due to the liver.
• 🦴 Ribs 11 and 12 protect the kidneys, which are found low in the back.
• 🩺 Kidneys are retroperitoneal, meaning they are located behind the peritoneal cavity.
• 🔍 The spleen should not be confused with the kidneys; the spleen is higher up and more lateral, located between ribs 9, 10, and 11 on the left side.
• 🩸 The kidneys have a superior and an inferior pole, with the adrenal glands sitting on top of them.
• 💉 Blood supply to the kidneys comes from the renal arteries, and blood is drained by the renal veins. The left renal vein is longer and can be compressed by the superior mesenteric artery.
• 💧 The kidneys filter blood, removing excess water and toxins, and this process involves significant blood flow.
• 🏞️ The internal structure of the kidney includes the cortex (outer layer) and medulla (inner layer), with urine collecting in the minor calyces, major calyces, and finally the renal pelvis before draining into the ureter.
• 🔬 Nephrons, the functional units of the kidney, include structures like Bowman's capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule, and the collecting duct.

Q & A

Where are the kidneys typically located in the human body?

The kidneys are located between the levels of T12 and L3, posteriorly in the abdominal cavity. The right kidney is slightly lower than the left due to the liver pushing it down.

What is the difference between the right and left kidneys in terms of position?

The right kidney is positioned slightly lower than the left kidney, by a few centimeters, due to the liver's influence.

What structures help protect the kidneys?

The kidneys are protected by the ribs, specifically ribs 11 and 12, as well as the posterior abdominal wall muscles.

What is the term used to describe the position of the kidneys relative to the peritoneal cavity?

The kidneys are described as being retroperitoneal, meaning they are located behind the peritoneal cavity.

What is the function of the adrenal glands located above the kidneys?

The adrenal glands, also known as suprarenal glands, produce adrenaline and other important hormones.

What major muscles are the kidneys situated on top of?

The kidneys are situated on top of the iliacus and quadratus lumborum muscles.

How does the anatomical position of the kidneys relate to their blood supply?

The kidneys have a rich blood supply due to their function in filtering the blood. They receive blood through the renal arteries and drain it through the renal veins.

What is the difference between the renal arteries and veins in terms of their position relative to the abdominal aorta?

The renal veins are anterior to the renal arteries. The left renal vein can be compressed by the superior mesenteric artery, which could potentially affect drainage.

What is the structure through which urine drains from the kidneys to the bladder?

Urine drains from the kidneys through the renal pelvis and into the ureters, which then descend to the bladder.

How are the functional units of the kidneys, known as nephrons, structured?

Nephrons consist of the Bowman's capsule, proximal convoluted tubules, loops of Henle, distal convoluted tubules, and collecting ducts. They are found in the cortex and medulla of the kidneys.

What is the significance of the renal pyramids and calyces in the kidney's structure?

The renal pyramids are part of the medulla where urine collects at their tips in the minor calyces. These minor calyces then drain into the major calyces and finally into the renal pelvis.

Outlines

00:00

🔍 Anatomy of the Kidney: Introduction and Overview

The speaker begins by discussing the anatomy of the kidney, emphasizing that the video will focus on the structure rather than the physiology of the kidneys. They introduce a model to assist with the explanation and note the position of the kidneys in the body, between vertebral levels T12 and L3. The right kidney is slightly lower than the left due to the liver's position. They explain the protective role of ribs 11 and 12 and the muscles around the kidneys, such as the psoas major, iliacus, and quadratus lumborum. The kidneys are described as retroperitoneal organs, meaning they are located behind the peritoneal cavity.

05:01

🩸 Blood Supply and Structure of the Kidneys

This paragraph dives into the blood supply and positioning of the kidneys in relation to other organs. The speaker explains the relationship between the kidneys and adjacent organs like the spleen, liver, pancreas, and colon. The renal veins and arteries, as well as their positions, are described in detail, noting how the left renal vein passes between the superior mesenteric artery and the aorta, potentially causing compression. The speaker emphasizes that the kidneys handle significant blood flow due to their role in filtering blood and mentions the renal hilum as the entry and exit point for blood vessels and the ureters.

10:02

🛠 Kidney Structures: Cortex, Medulla, and Urine Collection

Here, the speaker explains the internal structure of the kidney, describing the cortex and medulla. They highlight the renal pyramids (or medullary pyramids), where urine collects at the tips and drains into minor calyces, which in turn lead to major calyces. The renal pelvis collects urine before it drains into the ureter, which transports it to the bladder. The speaker emphasizes the three-dimensional structure of the pyramids and the muscular nature of the ureter, allowing urine flow even in challenging conditions like zero gravity.

🔬 Nephrons and the Filtration Process

The final section discusses the nephron, the functional unit of the kidney. The speaker explains the blood flow through the afferent and efferent arterioles and describes structures such as the Bowman's capsule, proximal and distal convoluted tubules, and the loop of Henle. They illustrate how substances that are not reabsorbed collect in the collecting ducts, which empty into the renal pyramids, continuing into the minor and major calyces. The paragraph concludes with a summary of the anatomical and structural information covered, linking it to the kidney's physiological function of blood filtration.

Keywords

💡Kidney

The kidney is a vital organ in the human body responsible for filtering waste products, excess water, and electrolytes from the blood to form urine. In the script, the kidney's location, structure, and function are discussed, emphasizing its role in maintaining homeostasis. The video mentions that kidneys are located between the levels of T12 and L3, with the right kidney slightly lower due to the liver's pressure.

💡Retroperitoneal

Retroperitoneal refers to the anatomical position of the kidneys, which are situated behind the peritoneal cavity. The script clarifies that while most of the gastrointestinal tract is within the peritoneal cavity, the kidneys are located posterior to this, hence the term 'retroperitoneal'. This positioning is crucial for understanding the kidney's relationship to other abdominal organs.

💡Suprarenal glands

Suprarenal glands, also known as adrenal glands, are endocrine glands that sit atop each kidney. As highlighted in the script, these glands produce important hormones such as adrenaline. Their mention in the video underscores the interconnectedness of the renal system with the body's hormonal regulation.

💡Peritoneum

The peritoneum is the lining of the abdominal cavity that surrounds most of the abdominal organs. The script explains that the kidneys are located behind this lining, which is why they are described as retroperitoneal. Understanding the peritoneum's role helps to visualize the kidneys' position relative to other abdominal organs.

💡Hilum

The hilum is the point where blood vessels, nerves, and ducts enter and exit an organ. In the context of the video, the hilum of the kidney is where the renal artery and vein, along with the ureter, connect to the kidney. This concept is essential for understanding the kidney's blood supply and the path of urine from the kidney to the bladder.

💡Cortex

The cortex is the outer layer of the kidney where filtration of blood occurs. The script describes the cortex as the 'edge side' of the kidney, emphasizing its role in the initial stages of urine formation. The presence of nephrons and their components, such as the glomerulus and Bowman's capsule, in the cortex is critical for the kidney's function.

💡Medulla

The medulla is the inner part of the kidney where urine is concentrated. The script mentions renal pyramids or medullary pyramids, which are part of the medulla. The medulla's structure facilitates the concentration and passage of urine through the collecting system to the renal pelvis.

💡Renal pelvis

The renal pelvis is a funnel-shaped structure in the kidney that collects urine from the calyces. As the script explains, the renal pelvis is where urine accumulates before it travels down the ureter to the bladder. This part of the kidney's anatomy is crucial for the transportation of urine.

💡Ureter

The ureter is the tube that carries urine from the kidney to the bladder. The script mentions that the ureter is muscular, allowing urine to be transported even in zero gravity. This keyword is important for understanding how urine moves from the kidney to the bladder.

💡Nephron

Nephrons are the functional units of the kidney where blood is filtered to form urine. The script describes the components of the nephron, such as the glomerulus, proximal convoluted tubule, loop of Henle, and distal convoluted tubule. Understanding nephrons is fundamental to grasping the kidney's role in filtering blood and maintaining electrolyte balance.

💡Loop of Henle

The Loop of Henle is a U-shaped tube in the kidney that plays a critical role in urine concentration. As described in the script, the loop descends into the medulla and ascends back towards the cortex, facilitating the reabsorption of water and the creation of a concentration gradient. This structure is essential for the kidney's ability to conserve water.

Highlights

Anatomy of the kidney will be discussed without diving into physiology.

The right kidney is slightly lower than the left due to the position of the liver.

The kidneys are located between the levels of T12 and L3 in the body.

Ribs 11 and 12 offer some protection to the kidneys, especially in the lower area.

Kidneys are retroperitoneal, meaning they are located behind the peritoneal cavity.

The spleen should not be confused with the kidneys; it is located higher and laterally.

The kidneys sit on top of two muscles: iliopsoas and quadratus lumborum.

Major nerves like ilioinguinal and iliohypogastric run posterior to the kidneys.

Blood enters and leaves the kidneys via the renal arteries and veins at the hilum.

The left renal vein can sometimes be compressed by the superior mesenteric artery.

Kidneys filter blood to remove excess water and toxins, making renal blood vessels quite large.

Each kidney contains a cortex and medulla; blood vessels reach into the cortex.

Urine collects at the tips of renal pyramids in the minor calyces.

The minor calyces drain into larger spaces called major calyces, which eventually lead to the renal pelvis.

Urine moves from the renal pelvis into the ureters, which transport it to the bladder.

Transcripts

boy this week if I talk about the

anatomy of the kidney I never know how

long my videos again at thee I always

aim the keys in shorter than they end up

being because I never know how long

they're going to be because I haven't

recorded them yet long edited them but

we're gonna talk about the kidney how

much could I possibly talk about the

kidney in a through the kidneys all that

much I'm not going to do the physiology

I'm not a physiologist I'm just going to

talk about the structures of the kidney

so here's a nice model he's a big model

and to do this is also good

however awesome torso model for Moses

let's use this guy right okay there's a

lot of it got my usual skeleton here

facing backwards because the kidneys are

fine posterior they're found between the

levels of our t12 and l3 the kidney on

the right is a little bit lower than the

kidney on the left just by a few

centimeters because of the liver pushing

it down but they're generally at these

levels here so though here's the last

width of t12 l1 l2 l3 l4 l5 l 1 2 3 so

they're directly very low down you know

they're down here and notice what the

ribs they curve around and they descend

so that the last couple of ribs ribs 11

and 12 are protecting the kidneys down

here right so they're you're kind of

you're kind of in here somewhere and in

fact the more inferior kidney the the

kidney on the right-hand side

he's only you know a couple of fingers

above this quest here so they're they're

very posterior and they're quite low

down they are there's a whole lot of

muscle

the posterior abdominal wall here which

is protecting the kidneys and we'll look

at that in a moment don't make the

kidneys up with clean the kidneys of

retroperitoneal well as retroperitoneal

means so the peritoneal cavity is the

cavity within the abdomen that all this

stuff is within the small intestine

stomach and all these bits and bobs

within the small intestine if you don't

know what I'm talking about with

peritoneum peritoneal cavity and median

trees go and have a look at my cling

film and territory and video now clear

it all up for you hopefully but if most

of the GI tract is within these

peritoneal sac within the greatest act

within the peritoneal cavity then the

kidneys are behind that that bag of

peritoneum there posterior is that bag

of peritoneum for there retroperitoneum

right

and we'll dishum will disembowel this in

a bit to see where those are the first

of all I want to point out this here

this is the spleen do not mix up the

kidneys for the spleen the spleen is

lateral so you have lateral this is and

it's higher up is between ribs what nine

ten and eleven and it's on the left side

two three one spleen two kidneys don't

look so here we go

and here are the two kidneys this one

has been partially dissected this one is

complete we can see the suprarenal

glands here these are the two adrenal or

supervene or glands will produce

adrenaline and a lot of very important

still region we'll have you his a spleen

here the kidney so there retroperitoneal

we've taken the peritoneum off to see

the two kidneys so this muscle here is

so as major here is iliacus they come

together to form iliopsoas and here you

see these these fibers here these are

the quadratus lumborum

so iliopsoas is a major hip flexor

and quadratus lumborum will give lateral

flexion of the spine so the two kidneys

are sat on top of those two muscles

there Illya Saracen quadratus lumborum

necessarily by far they've got the nice

facial faces and we've got the imio

inguinal and the iliohypogastric nerve

of running around from the lumbosacral

plexus posterior to the two kidneys in

these three muscle layers of muscle here

forming the abdominal wall to get around

here and we can see the blood vessels we

talked about the kidneys having a

superior pole and an inferior pole I'm

taking all this stuff out but the left

kidney so you see the pancreas here the

stomach goes on top if we take the

stomach out you can see there's a little

bit of a superior pole of the kidney in

here here's the adrenal gland here's the

spleen here's the pancreas if we take

this out again so you can see if the

pancreas is running across the mid part

of the left kidney and the inferior part

of the kidney wallet here's the splenic

flexure of the large colon so that's up

here and look here's the hepatic flexure

here up against this kidney and then of

course we've got the liver covering much

of this side

and the stomach goes in there now here's

the inferior vena cava and here's the

aorta so the blood supply and drainage

to and from the kidneys from the renal

arteries in the renal vein

but look the renal veins are anterior

and the renal arteries are posterior if

this is the abdominal aorta we see these

three anterior branches here the celiac

trunk the superior mesenteric artery and

the inferior mesenteric artery supplying

blood to the GI tract and look how this

left renal vein gets trapped between the

superior mesenteric artery as it comes

out of the aorta and goes to the GI

tract that's an interesting piece of

anatomy there I mean there's a

possibility that drainage through the

renal vein could be affected by the

superior mesenteric artery compressing

it doing funny things right so the

inferior vena cava the blood drains from

the kidney through these renal veins to

the inferior vena cava and here is one

renal artery here on the right the other

being larger on the left is hidden so

the author is is to the left for the

renal artery on the right is longer the

renal artery on the left is shorter and

these are big blood vessels because of

course the function of the kidney is to

look at the blood to take out excess

water to take out toxins and has a few

other jobs so the kidneys see a lot of

blood because their job is to do with

filtering the blood so these are big

blood vessels the blood vessels enter

and leave the kidneys at the hilum just

like most organs have a highland where

things go in and out so the kidneys

complete around here has this hilum here

with renal arteries and veins enter and

leave but also we see the ureter coming

out here

year to descending down on either side

to the bladder we can see here some of

the structure of the kid you go let me

get a bigger model so here we can see on

this model those ureters are complete

and they descend down to the bladder

here and into the bladder on either side

but we're not talking about the ureters

and below today we're talking about the

kidney now if we like many organs the

kidney is described as having a cortex

on the edge side and the does root issue

on the inside but you can see that the

blood vessels are passing into the

cortex and these here so these are

cortical columns this is a cortex around

here these are the renal pyramids or the

medullary pyramids so you can imagine as

we saw on the other model that these are

cut in sections and coronal sections are

their flattened triangles almost but if

they were in three dimensions maybe more

the pyramidal shape so urine collects at

the tip of the renal pyramids and this

small space here and here and here these

small spaces are the minor calyce's

so urine drip drip clip collecting the

minor calyce's so three or four of these

minor calyce's will drain into a larger

space and major calyx again imagine

these in three dimensions we've got some

pyramids out here as well some KFC minor

K diffusion three dimensions and then

three or four of these major Calif fees

will drain into this larger space here

and this larger space is the renal

pelvis so the urine collections of renal

pelvis and from the renal pelvis we find

the ureter and the yearling can drain

them ureter so the bladder has loss the

ureter is muscular so you can do this

upside down and you can do this in

zero gravity it'll work oh here's the

bigger model so here's our cortex here's

the medulla and the gallery pyramid that

hero our hero our nephrons you can see

the blood vessels coming in here these

are the efferent and afferent arterioles

there's the Bowman's capsule so there

are the capillaries there and then here

is proximal convoluted tubules there is

the loop of Henle descending down into

the medulla the big is a bigger one down

here loop of Henle and then we have the

distal convoluted tubule and this is the

collecting duct here the collecting

system so you know the fluid passes

through this tubules

the stuff does not reabsorbed back into

the blood collects in the collecting

tubules here you can see how it collects

at the tip of the medullary pyramid and

down here would be the four minor calyx

here as your Bowman's capsule so you

find these in the cortex and you find

the loops of Henle and the collecting

systems in the medulla so how's that

we've talked about where you find the

kidneys anatomically the structures

nearby we've talked about their blood

supply and we've talked about you and

collecting systems and we've talked

about the structures within the kidney

and that's about it all right so the

structure of the kidney relate to the

function of the kidneys when you look at

the physiology when you look all those

ducks and tubules just advance your

anatomy and your understanding will be

more complete see Taj is going to be

short