Hello Kidney

Where is the urinary system located?

Half in the retroperitoneal space, and half in the peritoneal space.

What are the cranial most organs of the urinary system?

The kidneys (right kidney slightly cranial to left)

What organ runs caudally into the urinary bladder?

Paired ureters.

What is the anatomic location of the kidneys?

In the dorsal part of the abdomen, ventral to and on either side of the first few lumbar vertebrae.

The kidneys are retroperitoneal to the abdominal cavity. What does this mean?

Meaning they live between the parietal peritoneum and the dorsal abdominal muscles.

Why are horse kidneys heart shaped?

They are compressed end to end, which can make them appear heart-shaped.

What species has kidneys that are divided into lobes and have a lumpy appearance?

Cattle

What species have kidneys that tend to be more plum shaped?

Feline

What is the external surface of the kidney covered with?

The capsule.

Where is the hilus located?

On the medial side.

What is the hilus?

The entry and exit point for blood and lymph vessels, nerves, and ureters.

The area where the hilus is located is known as the?

Renal pelvis.

On a cut portion, the outer portion of the kidney is known as the?

Cortex

On a cut portion, the inner portion of the kidney is known as the?

Medulla, it surrounds the renal pelvis.

What is the renal pelvis lined with?

Transitional epithelial cells.

In certain species, such as cattle and pigs, the medulla can have what kind of appearance?

A “candy corn”.

What is the “candy corn” appearance of the medulla also known as?

Multipyramidal or multilobar medulla.

What kind of medulla do dogs, horses, and cats have?

A unilobar or unipyramidal medulla.

What directs urine into the renal pelvis or directly into the ureter in cattle?

Calyces.

What is the basic functional unit of the kidney?

The nephron.

What is a nephron composed of?

A renal corpuscle, a proximal convoluted tubule, a loop of Henle, and a distal convoluted tubule.

What do afferent arterioles do?

Deliver blood to the nephron.

What do efferent arterioles do?

“Exit” blood from the nephron.

Where is the renal corpuscle located?

In the cortex.

What is the renal corpuscle made up of?

The Glomerulus and Bowman’s capsule.

What are the two layers that make up Bowman’s capsule?

The visceral (inner) and the parietal (outer) layer.

What is the space between the visceral and parietal layers called?

The capsular space.

What is the proximal convoluted tubule (PCT)?

A continuation of the capsular space of bowman’s capsule.

What is the longest tubular part of the nephron?

The PCT.

Where does the loop of Henle travel?

The loop of Henle continues from the PCT, descends into the medulla, hangs a U-turn, and heads back to the cortex

What is the distal convoluted tubule (DCT)?

The continuation of the loop of Henle and these empty into the collecting ducts.

Collecting ducts carry tubular filtrate into the calyces, which lead to the?

Renal pelvis.

Where do the two ureters exit the kidneys at?

The hilus and connect to the urinary bladder near the neck, at its caudal end, they are a continuation of the renal pelvis.

What are the three layers of the ureters?

The outer fibrous layer, the middle muscular layer, and the inner epithelial layer.

What allows the ureters to stretch as urine passes through them?

Transitional epithelium.

What do peristaltic contractions from the muscular layer do?

Keep urine flowing to the bladder regardless of the position of the animal.

Why do ureters enter the bladder at such an oblique angle?

They collapse when the bladder is full to keep urine from backing up into the ureter, but are still able to enter the bladder.

What is the function of the urinary bladder?

To collect, store, and release urine.

What are the two parts of the urinary bladder?

The muscular sac and the neck.

What creates the trigone of the bladder?

 The two openings from the ureters and the opening of the urinary bladder into the urethra.

The trigone region is where we often see what?

Tumors on the urinary bladder.

What kind of tissue lines the urinary bladder?

Transitional epithelium.

What does the transitional epithelium tissue in the urinary bladder do?

Stretches as the bladder becomes filled with urine.

What is the detrusor muscle?

Smooth muscle bundles that run lengthwise, obliquely, and in a circular direction.

Describe the appearance of transitional epithelium tissue when the urinary bladder is empty.

It is '“puffy” looking.

Describe the appearance of transitional epithelium tissue when the urinary bladder is full.

It is '“flattened” looking.

What is micturition?

The expulsion of urine from the urinary bladder into the urethra for elimination from the body.

Where does the renal artery branch from?

The abdominal aorta.

What do the afferent glomerular arterioles do?

Carry blood into the glomerular capillaries of the renal corpuscle.

The glomerular capillaries are a continuation of what?

The afferent arterioles.

The renal vein leaves the kidney at the hilus and does what?

Joints the abdominal portion of the caudal vena cava.

Where is the purest blood in the body found?

In the renal vein.

What are the kidneys supplied by?

The sympathetic nervous system, which can temporarily decrease urine production.

What is the acronym for the functions of the kidney?

WAVE

What does the W in WAVE stand for?

Waste elimination: the primary job of the kidneys is to filter the blood and remove harmful substances.

What does the A in WAVE stand for?

Acid-base balance: the kidneys help maintain acid-base homeostasis by removing acidic hydrogen ions and basic bicarbonate ions from the blood. This helps maintain proper blood pH.

What does the V in WAVE stand for?

Fluid Volume/Blood pressure regulation: Kidneys contain internal receptors that monitor blood pressure and adjust the fluid volume of the blood to avoid major swings in pressure.

What does the E in WAVE stand for?

Endocrine, or hormonal signaling: The kidneys produce hormones, regulate the release of hormones from other organs, and are themselves influenced by hormones.

What happens when kidneys fitler the blood?

Useful substances are returned to circulation, and waste products (urea, ammonia) are secreted from the bloodstream into the fluid that eventually becomes urine.

What is the blood filtration process by the kidneys include?

Filtration, reabsorption, and secretion.

What happens when the kidneys are damaged?

 Large molecules like proteins leave the body when they shouldn’t, and waste products like urea and ammonia are trapped in the bloodstream.

Where does the filtration of the blood take place?

In the renal corpuscle. (size related process)

What allows molecules to pass into the capsular space in blood filtration?

Fenetrations (pores) in the capillary endothelium and a fascinating blood pressure gradient.

What is the glomerular filtration rate (GFR) used for?

 To describe how fast blood plasma is filtered as it passes through the glomerulus.

What are the two main mechanisms the kidneys use to maintain systemic pH?

Reabsorption of bicarbonate from the urine back into the blood and the secretion of H+ ions back into the urine.

What is urine volume is determined by?

The amount of water contained in the tubular filtrate when it reaches the renal pelvis.

What secretions by the adrenal cortex handle the majority of urine volume regulation?

Antidiuretic hormone (ADH) and aldosterone from the posterior pituitary.

What happens when blood pressure falls?

The Renin-angiotensin-aldosterone system (RAAS) responds to bring it back up to a normal level.

What do the hormones secreted by the kidneys act as?

Signals

What does erythropoietin do?

Signals bone marrow to produce red blood cells

What does ADH do?

Helps regulate urine volume by stimulating passive water reabsorption.

What does renin do?

Mediates extracellular volume and arterial vasoconstriction.

Aldosterone stimulates what?

active sodium resorption.

Vitamin D (calcitriol) is produced in the kidney and it can help?

promote calcium absorption from the GI tract.

What are the tests designed to evaluate the urinary system?

CBC, chemistry, UA, BRAFF, and imaging.