anat lab 16 : urinary Flashcards
list the structures and how they work together
The urinary system consists of two kidneys, two ureters, one urinary bladder and one
urethra. As the kidneys filter blood plasma to produce urine, they maintain the electrolyte,
acid-base and fluid balances in the blood. The kidneys produce the enzyme renin, two
hormones, calcitriol and erythropoietin, and can synthesize glucose. Lastly the kidneys
excrete wastes by forming urine. Urine contains the byproducts of metabolic reactions
(urea, ammonia, billirubin, creatinine, and uric acid), drugs and environmental toxins. The
ureters, bladder and urethra act as transport and storage areas.
describe the anatomy of the kidneys
The kidneys are located just above the waist, posterior to the peritoneum of the abdominal
cavity (retroperitoneal). The medial face of each kidney contains a notch, the hilum of
the kidney, through which blood vessels, nerves, lymphatic vessels, and the ureters enter
and exit.
description and function capsule
The fibrous capsule of the urinary system is a thin, tough layer of connective tissue that surrounds each kidney.
Description:
- It is a smooth, transparent membrane that tightly adheres to the kidney’s surface.
- Made of dense irregular connective tissue, it provides strength and flexibility.
Function:
1. Protection: Shields the kidney from physical trauma and infections.
2. Structural Support: Helps maintain the kidney’s shape and integrity.
3. Barrier: Prevents the spread of infections to and from the kidney.
This capsule plays a vital role in safeguarding the kidney’s delicate internal structures.
hilum of the kidney description and function
The hilum of the kidney is a concave, slit-like area located on the medial side of each kidney.
Description:
- It is the entry and exit point for structures associated with the kidney.
- Includes the renal artery, renal vein, ureter, lymphatic vessels, and nerves.
- Leads into a space within the kidney called the renal sinus.
Function:
1. Pathway for Blood Vessels: The renal artery brings oxygenated blood into the kidney, and the renal vein carries filtered blood out.
2. Urine Transport: The ureter exits the kidney at the hilum, carrying urine to the bladder.
3. Lymphatic and Nervous Supply: The hilum provides a route for lymphatic drainage and nerve innervation to and from the kidney.
renal cortex description and function
The renal cortex is the outer layer of the kidney, located just beneath the fibrous capsule and surrounding the inner medulla.
Description:
It has a granular appearance due to the presence of millions of tiny structures called nephrons, specifically the glomeruli and convoluted tubules.
It is lighter in color compared to the medulla.
Function:
1. Filtration: Houses the glomeruli, where blood filtration begins, removing waste products and excess substances.
2. Reabsorption and Secretion: Contains the proximal and distal convoluted tubules, which reabsorb essential nutrients and secrete waste products into the forming urine.
3. Hormone Production: Plays a role in producing erythropoietin (EPO), which stimulates red blood cell production.
renal medulla description and function
The renal medulla is the innermost part of the kidney, located beneath the renal cortex.
Description:
It is made up of renal pyramids, which are cone-shaped structures.
The apex of each pyramid (the renal papilla) points toward the renal pelvis.
It has a striped appearance due to parallel arrangements of tubules and blood vessels.
Function:
1. Concentration of Urine: Contains the loops of Henle and collecting ducts, which concentrate urine by reabsorbing water and salts.
2. ransport of Urine: Directs urine from the nephrons into the renal pelvis via the renal papillae.
3. Salt and Water Regulation: Plays a critical role in maintaining the body’s salt and water balance through the countercurrent mechanism in the loops of Henle.
The renal medulla is vital for producing concentrated urine and regulating the body’s fluid balance.
renal pyramids description and function
The renal pyramids are triangular-shaped structures located within the renal medulla of the kidney.
Description:
- Each kidney contains several renal pyramids.
- They are striped in appearance due to parallel nephrons, loops of Henle, and collecting ducts.
- The apex of each pyramid, called the renal papilla, points toward the renal pelvis.
Function:
1. Urine Collection: The collecting ducts within the pyramids collect urine from the nephrons and funnel it toward the renal papilla.
2. Urine Transport: Urine flows from the renal papillae into the minor calyces, eventually leading to the renal pelvis and ureter.
3. Water and Salt Regulation: The loops of Henle within the pyramids play a key role in concentrating urine by reabsorbing water and salts.
The renal pyramids are essential for urine production, concentration, and transportation.
renal papilla description and function
The renal papilla is the tip or apex of a renal pyramid located in the renal medulla of the kidney.
Description:
- It is the narrow, rounded end of the renal pyramid.
- It projects into a small cup-shaped structure called the minor calyx.
- Contains openings of the collecting ducts, where urine exits the pyramids.
Function:
1. Urine Drainage: Acts as the passage through which urine flows from the collecting ducts into the minor calyx.
2. Transport to the Renal Pelvis: Facilitates the movement of urine from the kidney tissue into the renal pelvis, which leads to the ureter.
The renal papilla is a critical structure for efficiently channeling urine out of the kidney toward the urinary tract.
renal columns
The renal columns are areas of cortical tissue that extend down between the renal pyramids in the kidney.
Description:
- Located in the renal medulla, but composed of the same tissue as the renal cortex.
- They appear as lighter, column-like structures separating the darker renal pyramids.
Function:
1. Support for Blood Vessels: Provide pathways for blood vessels (interlobar arteries and veins) to reach deeper parts of the kidney.
2. Structural Support: Help anchor and separate the renal pyramids, maintaining the structural integrity of the kidney.
3. Housing Nephrons: Contain portions of the nephron structures involved in filtering and transporting urine.
The renal columns are essential for facilitating blood flow within the kidney and providing structural organization.
minor and major calyx description and function
Minor Calyx
Description:
- The minor calyx is a small, cup-shaped structure located at the tip of each renal papilla.
- Each kidney has several minor calyces, which surround the renal papillae to collect urine.
Function:
1. Urine Collection: Receives urine from the renal papillae of the renal pyramids.
2. Urine Transport: Channels the collected urine into the major calyces.
Major Calyx
Description:
- The major calyx is a larger, funnel-like structure formed by the convergence of two or more minor calyces.
- Each kidney typically has 2-3 major calyces.
Function:
1. Urine Collection: Collects urine from the minor calyces.
2. Urine Transport: Directs urine into the renal pelvis, the next structure leading to the ureter.
Both structures are crucial for moving urine from the kidney tissue to the ureter while maintaining an organized flow.
renal pelvis description and function
Renal Pelvis
Description:
- The renal pelvis is a funnel-shaped structure located in the central part of the kidney.
- It is formed by the convergence of the major calyces.
- The renal pelvis narrows at its lower end to become the ureter, which transports urine to the bladder.
Function:
1. Urine Collection: Serves as a reservoir for urine, collecting it from the major calyces.
2. Urine Transport: Channels urine into the ureter for delivery to the urinary bladder.
The renal pelvis is essential for efficiently moving urine out of the kidney and into the urinary system for excretion.
ureter description and function
Ureter
Description:
- The ureter is a pair of muscular, tube-like structures (one for each kidney) that extend from the renal pelvis of the kidney to the urinary bladder.
- Each ureter is approximately 25–30 cm (10–12 inches) long.
- Its walls are made of smooth muscle, lined with a mucous membrane, and capable of peristalsis (wave-like contractions).
Function:
1. Urine Transport: Carries urine from the renal pelvis to the urinary bladder.
2. Prevention of Backflow: A one-way valve at the bladder-ureter junction prevents urine from flowing back into the ureter.
3. Regulation: Peristaltic movements ensure a steady flow of urine, regardless of body position or gravity.
The ureters are vital for connecting the kidneys to the bladder, ensuring the smooth and controlled movement of urine for storage and eventual excretion.
renal artery vs renal vein description and function
Renal Artery
- Description: A thick, muscular blood vessel that branches from the aorta.
- Function: Carries oxygen-rich blood from the heart to the kidneys. This blood also contains waste and nutrients for filtration.
Renal Vein
- Description: A thinner, wider blood vessel that connects the kidney to the inferior vena cava.
- Function: Carries oxygen-poor and filtered blood (after waste removal) from the kidneys back to the heart.
Key Difference:
- Renal artery brings blood to the kidneys for filtration.
- Renal vein takes filtered blood away from the kidneys.
what are nephrons and what do they consist of?
Nephrons are the basic functional unit of the kidneys. A nephron consists of a renal
corpuscle and a renal tubule.
describe the renal corpuscle
The renal corpuscle includes a glomerulus inside a double-walled glomerular (Bowman’s)
capsule. The glomerulus is a network of blood capillaries. As blood passes through the
capillaries, blood pressure forces materials, the filtrate, into the capsular space
surrounding the glomerulus, where it passes to the renal tubule.
what are the steps in urine formation
As blood passes through the
capillaries, blood pressure forces materials, the filtrate, into the capsular space
surrounding the glomerulus, where it passes to the renal tubule. This is the first step of
urine formation, called glomerular filtration.
The second and third steps, tubular reabsorption and tubular secretion, take place in the
renal tubules and collecting ducts. A renal tubule has three main sections: the proximal
convoluted tubule, a nephron loop (Loop of Henle), and a distal convoluted tubule.
Several distal convoluted tubules empty into one collecting duct. Collecting ducts unite to
form papillary ducts, which drain into the minor calyces.
what happens in the renal tubules
In the renal tubules, water and many useful solutes are returned to the blood by tubular
reabsorption. Wastes, drugs and excess ions are secreted into the fluid in the renal tubules
by tubular secretion for excretion.
describe where the afferent glomerular arterioles lead to?
One afferent glomerular arteriole enters each glomerular capsule and divides into a
tangled network of capillaries comprising the glomerulus. The capillaries reunite to form the
efferent glomerular arteriole as they exit the glomerular capsule. Efferent arterioles
divide to form the peritubular capillaries or vasa recta around the renal tubules. These
capillaries play an important role in tubular reabsorption and tubular secretion.
description and function of the nephron
Description:
- A tiny filter in the kidney.
- Each kidney has about 1 million nephrons.
- It has two main parts:
1. Filter (Renal Corpuscle): Filters blood to remove waste.
2. Tube (Renal Tubule): Adjusts water and nutrients, making urine.
Function:
The nephron cleans your blood and balances your body’s fluids in four steps:
- Filtration: Filters out waste, water, and small substances from the blood.
- Reabsorption: Returns useful things like water and nutrients to the blood.
- Secretion: Adds extra waste and unwanted stuff to the urine.
- Excretion: Sends the urine to the bladder to be removed from the body.
It’s like a tiny water filter that keeps your blood clean!
renal corpuscle:
glomerulus
capsular space
glomerular capsule
description and function
1. Glomerulus
- Description: A ball of tiny blood capillaries inside the renal corpuscle.
- Function: Acts as a filter. It allows water, small molecules, and waste to leave the blood while keeping large proteins and blood cells inside.
2. Capsular Space
- Description: The small gap between the glomerulus and the glomerular capsule.
- Function: Collects the filtered fluid (called filtrate) from the glomerulus. This is the starting point for urine formation.
3. Glomerular Capsule (Bowman’s Capsule)
- Description: A cup-shaped structure surrounding the glomerulus.
- Function: Protects the glomerulus and directs the filtrate into the tubules for further processing.
Summary:
- Glomerulus filters blood.
- Capsular space collects the filtered fluid.
- Glomerular capsule protects and guides the filtrate to the next step in the nephron.
function and description of renal corpuscle
where blood plasma is filtered
renal tubule function and associated structures
The renal tubule is a part of the kidney that collects filtered blood products and produces urine. The
renal tubule’s functions include:
Reabsorbing vital substances: The renal tubule absorbs water, electrolytes, amino acids, and ions.
Eliminating excess substances: The renal tubule removes excess substances from the body through urine
Proximal convoluted tubule (PCT)
The first segment of the renal tubule, located in the renal cortex. The PCT reabsorbs and secretes water and solutes.
Loop of Henle
A structure in the renal tubule that helps with water conservation and reabsorbing nutrients.
Descending limb
Highly permeable to water but impermeable to ions. The descending limb’s thin segment is the primary site of water reabsorption.
Ascending limb
Impermeable to water but highly permeable to ions. The ascending limb’s thin segment moves sodium and chloride out of the tubule, while the thick segment moves sodium, potassium, and chloride out.
distal convoluted tubule The distal convoluted tubule (DCT) is a short nephron segment, interposed between the macula densa and collecting duct. Even though it is short, it plays a key role in regulating extracellular fluid volume and electrolyte homeostasis.
juxtaglomerular apparatus and macula densa
The Juxtaglomerular Apparatus helps control blood pressure and fluid balance.
The Macula Densa acts like a sensor for salt levels in the urine.
macula densa is found inside the juxtaglomerular apparatus
collecting duct description and function
Collecting Duct
Description:
A long tube in the nephron that connects to many nephrons.
It runs through the kidney’s inner parts (medulla) and ends at the renal pelvis.
Shared by multiple nephrons.
Function:
1. Final Adjustment:
Regulates the amount of water and electrolytes in urine.
Controlled by hormones like ADH (antidiuretic hormone) and aldosterone to either save water or release more.
2. Urine Collection:
Collects urine from the nephron and sends it to the renal pelvis for transport to the bladder.
what is this
urothelium of the urinary bladder
what is this
transitional epithelium fo the ereter
what are the normal characteristic of urine
name abnormal constituents in urine and their causes
