urinary 2

Question 1

blood flow pathway

Answer 1

The kidneys continuously cleanse the blood and adjust its composition, so it is not surprising that they have a rich blood supply (see Figure 15.2b and c). Approximately one-quarter of the total blood supply of the body passes through the kidneys each minute. The artery supplying each kidney is the renal artery. As the renal artery approaches the hilum, it divides into segmental arteries, each of which gives off several branches called interlobar arteries, which travel through the renal columns to reach the cortex. At the cortex-medulla junction, interlobar arteries give off the arcuate (ar′ku-at) arteries, which arch over the medullary pyramids. Small cortical radiate arteries then branch off the arcuate arteries to supply the renal cortex. Venous blood draining from the kidney flows through veins that trace the pathway of the arterial supply but in a reverse direction—cortical radiate veins to arcuate veins to interlobar veins to the renal vein, which emerges from the kidney hilum and empties into the inferior vena cava. (There are no segmental veins.)

Question 2

nephron

Answer 2

Nephrons (nef′ronz) are the structural and functional units of the kidneys and are responsible for forming urine. Each kidney contains over a million of these tiny filters. In addition, there are thousands of collecting ducts, each of which collects fluid from several nephrons and conveys it to the renal pelvis. Figure 15.3, shows the anatomy and relative positioning of nephrons and collecting ducts in each kidney.

Question 3

renal tubule and corpuscle

Answer 3

1. Renal Corpuscle (filtration happens here)
   Glomerulus: a ball of capillaries that filters blood

Bowman’s capsule: surrounds the glomerulus and collects the filtrate

2. Renal Tubule (where the filtrate gets modified)
   This is the “nephron tube” part you’re asking about:

Proximal convoluted tubule (PCT) – reabsorbs nutrients like glucose and amino acids

Loop of Henle – concentrates urine by reabsorbing water and salt

Distal convoluted tubule (DCT) – fine-tunes salt and pH balance

Collecting duct (not technically part of the nephron, but connects to many) – collects urine from many nephrons and sends it to the renal pelvis

Renal corpuscle – where filtration of blood begins

Renal tubule – where the filtered fluid is processed into urine

🔸 The renal corpuscle is made of:
Glomerulus = a tangled “ball” of capillaries (blood flows in here)

Glomerular (Bowman’s) capsule = a cup-like structure that wraps around the glomerulus to collect the filtrate

🧠 Key Structure: Podocytes
These are special cells on the inner layer of the capsule

They wrap around the glomerulus with “foot processes” that form filtration slits

These slits allow water and small molecules (like glucose, ions, and urea) to pass into the capsule
➡️ But block larger molecules (like proteins and blood cells) from passing through

Question 4

juxtomedullary and renal cortex

Answer 4

Two Types of Nephrons:
Cortical Nephrons

Make up 85% of all nephrons

Located almost entirely in the renal cortex

Have short loops of Henle

Function mostly in filtration and basic urine formation

Juxtamedullary Nephrons

Located close to the border of the cortex and medulla

Have long loops of Henle that dip deep into the medulla

Important for making concentrated urine (especially during dehydration)

🟨 Collecting Ducts:
Each duct collects urine from multiple nephrons

They run through the medullary pyramids (which is why the pyramids look striped)

They carry urine to:

Calyces

Renal pelvis

Ureter → Bladder → Urine exits the body

🔁 Summary:
Cortical nephrons = shallow, common

Juxtamedullary nephrons = deep, help concentrate urine

Collecting ducts = final pathway that sends urine out of the kidney

Let me know if you want a visual flowchart or step-by-step of how urine travels from nephron to bladder!

Ask ChatGPT
You said:
so are these these difrent secoins of the nephron or is it nephrones that are in the renal cortex vis the medullary

ChatGPT said:
Great question! Let’s clear it up:

You’re talking about two different types of nephrons, not different parts of the same nephron.

🧬 There are two types of nephrons in the kidney:
1. Cortical Nephrons
Make up most (85%) of your nephrons.

Located almost entirely in the renal cortex (the outer part of the kidney).

Their loops of Henle are short and don’t go deep into the medulla.

Main job: filter blood and make regular urine.

2. Juxtamedullary Nephrons
   Only about 15% of nephrons.

Located near the border between the cortex and medulla.

Their loops of Henle are long and dip deep into the medulla (the inner part).

Main job: concentrate urine (important when you’re dehydrated).

🧠 So to answer your question:
It’s not that one nephron is in both the cortex and medulla as different sections — it’s that different nephrons are located differently based on their structure and function:

Cortical nephrons stay mostly in the cortex.

Juxtamedullary nephrons extend deep into the medulla.

Would you like a simple diagram or analogy to help you picture it?

You said:
so renal cortical nephrons are normal pee fomulatng nephrons thatare in deep of the renal cortex but the juxtmendalary nephron is deep in the medullary for people who are dehdrated and the pee is more concentraded

ChatGPT said:
Exactly! You nailed it. Here’s a quick recap with your wording polished a bit:

Cortical nephrons are the regular pee-making nephrons located mostly in the outer part of the kidney (renal cortex). They handle the usual filtering and urine formation.

Juxtamedullary nephrons have loops that dive deep into the renal medulla. These are the ones that help concentrate urine, especially important when you’re dehydrated so your body saves water.

If you want, I can explain how juxtamedullary nephrons concentrate urine!

Question 5

two capilery beds

Answer 5

Each nephron has two sets of capillaries:

Glomerulus: This is a special tuft of capillaries where blood is filtered.

Peritubular capillaries: These surround the renal tubules and help reclaim most of the filtered substances back into the blood.

Blood flows into the glomerulus via the afferent arteriole (wider diameter), and out via the efferent arteriole (narrower diameter).

Because the afferent arteriole is wider than the efferent arteriole, this creates high pressure inside the glomerulus, which pushes fluid and small solutes (like water, glucose, ions) out of the blood into the Bowman’s capsule. This fluid is called the filtrate.

Then, the filtrate travels through the renal tubule where most of the water and useful substances (about 99%) are reabsorbed into the blood via the peritubular capillaries.

Only about 1% of the original filtered water ends up in urine

The rest is reclaimed by the body to maintain hydration and blood pressure

The afferent arteriole is wider than the efferent arteriole.

This difference in diameter creates higher pressure inside the glomerulus.

That high pressure is what forces fluid and small solutes (like water, glucose, sodium, etc.) out of the blood and into the Bowman’s capsule — this process is called filtration.

📌 Key point: The glomerulus is a capillary bed, not a “tubule” — it’s inside the renal corpuscle. The renal tubule (proximal tubule, loop of Henle, etc.) comes after filtration happens.

Question 6

peritublar

Answer 6

Peritubular Capillaries:
They come from the efferent arteriole (which drains the glomerulus).

Unlike the glomerulus (which is high-pressure and designed for filtration), peritubular capillaries are:

Low-pressure

Porous

Adapted for absorption, not filtration.

🔁 Function:
They run alongside the renal tubule, closely hugging it.

Their main job is to reabsorb water and solutes (like glucose, amino acids, sodium, etc.) that the body wants to keep.

These substances are pulled from the filtrate (which is moving through the nephron) and go back into the bloodstream via the peritubular capillaries.

🛣️ Where does the blood go next?
Peritubular capillaries drain into:

Cortical radiate veins

→ Arcuate veins

→ Interlobar veins

→ eventually into the renal vein → and back to the heart.

🧠 Summary:
The glomerulus filters, and the peritubular capillaries reabsorb.
One starts the process of forming urine, and the other helps reclaim valuable materials.

Question 7

golumar non selective

Answer 7

Glomerular filtration is nonselective in the sense that it filters everything small enough to pass through the filtration slits — but large elements like red blood cells (RBCs) and proteins are too big to pass through the glomerular membrane.

Here’s how it works:
✅ What does pass through the filter:

Water

Glucose

Salts (electrolytes like Na⁺, K⁺)

Amino acids

Urea and other small waste products

❌ What doesn’t pass through:

Red blood cells

White blood cells

Platelets

Large proteins (like albumin)

Why?
The glomerular membrane and podocytes have small filtration slits — kind of like a sieve. Only small molecules fit through. So blood cells and large proteins stay in the bloodstream and do not enter the nephron.

If RBCs or proteins are found in urine, it’s a sign of kidney damage or disease (like glomerulonephritis).

Question 8

glomarus

Answer 8

Once blood plasma is filtered through the glomerulus into the Bowman’s capsule, the fluid is called filtrate.

Filtrate is basically plasma without the blood proteins and blood cells because those are too large to pass through the filtration membrane.

If proteins or blood cells are found in the urine, it usually means there’s damage or a problem with the glomerular filter.

Normal blood pressure is essential because it provides the force (pressure) needed for filtration.

If blood pressure falls too low, the pressure in the glomerulus isn’t enough to push fluid out, and filtrate formation stops, meaning the kidneys can’t filter blood properly.

Question 9

what causes less filtrate output

Answer 9

An abnormally low urinary output is called oliguria (ol″i-gu′re-ah) if it is between 100 and 400 ml/day, and anuria (ah-nu′re-ah) if it is less than 100 ml/day. Low urinary output usually indicates that glomerular blood pressure is too low to cause filtration, but anuria may also result from transfusion reactions and acute inflammation or from crushing injuries to the kidneys