Urinary System Flashcards
What do the kidney do kidney?
Filters blood and produce urine
What are the functions of the kidney?
- Excrete waste (ammonia, urea, uric acid, creatinine, urochrome, toxins and drugs).
- Regulate blood pressure.
- Regulate chemical composition of blood (pH, solute concentration).
- Regulate erythropoiesis.
- Produce erythropoietin (EPO) in response to hypoxia.
- Activate vitamin D.
- Stimulated by parathyroid hormone
What type of structure of the kidney is this?
_____-Outer region contains renal corpuscles and tubules of nephrons.
Renal cortex
What type of structure of the kidney is this?
_____-region deep to the cortex that contains renal columns and pyramids
Renal Medulla
In renal Medulla:
______-are connective tissue extensions that radiate downward from the cortex through the medulla to separate the most characteristic features of the medulla, the renal pyramids and renal papillae. The renal columns also serve to divide the kidney into 6–8 lobes and provide a supportive framework for vessels that enter and exit the cortex.
renal columns
In renal Medulla:
_____-contain collecting ducts and loops of Henle (nephron loops).
o Renal papillae are the ends of collecting ducts that transport urine made by nephrons to the minor calyces.
Pyramids
Minor calyces join to form _____-
major calyces
Major calyces come together to form the _______
renal pelvis
______-that drains into the ureter at the renal hilum (concave medial surface).
renal pelvis
_____-transport urine from kidneys to urinary bladder.
Ureters
_____-Lined by mucosa with a transitional epithelium surrounded by a layer of smooth muscle.
o As urine passes through the ureter, it does not passively drain into the bladder but rather is propelled by waves of peristalsis.
Ureters
As the _____ enter the pelvis, they sweep laterally, hugging the pelvic walls. As they approach the bladder, they turn medially and pierce the bladder wall obliquely. This is important because it creates an one-way valve (a physiological sphincter rather than an anatomical sphincter) that allows urine into the bladder but prevents reflux of urine from the bladder back into the ureter.
ureters
______-collects urine from both ureters and stores urine until voiding (emptying of the bladder is commonly known as urination or more formally known as micturition).
Urinary bladder
• The ______ bladder is a highly distensible organ allowing expansion as urine accumulates. The interior surface is made of transitional epithelium that is structurally suited for the large volume fluctuations of the bladder. When empty, it resembles columnar epithelia, but when stretched, it “transitions” (hence the name) to a flat squamous appearance.
Urinary bladder
The bulk of the wall of the urinary bladder is comprised of irregular crisscrossing bands of smooth muscle collectively called the _______
detrusor muscle.
_____-transports urine from the bladder to the outside of the body for disposal.
Urethra
o In both sexes the proximal urethra is lined by ______ whereas the terminal portion is a nonkeratinized, stratified squamous epithelium. In the longer male urethra, pseudostratified columnar epithelium lines the urethra between these two cell types.
transitional epithelium,
• The urethra in both males and females begins inferior and central to the two ureteral openings forming the three points of a triangular-shaped area at the base of the bladder called the______(Greek tri- = “triangle” and the root of the word “trigonometry”).
trigone
The proximal entrance to the urethra from the urinary bladder is surrounding by the internal urinary sphincter, consisting of smooth muscle and the external urinary sphincter below it consisting of _____-
skeletal muscle.
Blood supply to the kidney:
Afferent arterioles carry blood into the ______ (a fenestrated capillary bed)
glomerulus
Blood supply to the kidney:
Blood flows out of the glomerulus into the _____
efferent arteriole
Blood supply to the kidney:
The efferent arteriole carries blood into ______
peritubular capillaries and vasa recta.
_____-the “functional units” of the kidney; they cleanse the blood and balance the constituents of the circulation
Nephrons
The glomerulus and Bowman’s capsule together form _____
renal corpuscle.
Renal corpuscle.
The afferent arterioles form a tuft of high-pressure fenestrated capillaries about 200 µm in diameter, called the ______
glomerulus.
Renal corpuscle.
These glomerular capillaries filter the blood based on particle size. After passing through the renal corpuscle, the capillaries form a second arteriole, the efferent arteriole that carries blood into a second capillary bed called the ________ (vasa recta in medulla).
peritubular capillaries
______-surrounding tubules in the renal cortex
Peritubular capillaries
______-surrounding the loops of Henle and collecting ducts in the medulla
vasa recta
_______form a capillary network around the nephron, before returning to the venous system. As the filtrate progresses through the nephron it is modified by reabsorption and secretion, these capillary networks recover most of the solutes and water, and return them to the circulation.
Peritubular capillaries and Vasa recta
The rest of the nephron consists of a continuous sophisticated tubule whose proximal end surrounds the glomerulus in an intimate embrace—this is_______
Bowman’s capsule.
Bowman’s capsule:
____-simple squamous epithelium
Parietal layer
Bowman’s capsule:
_____-podocytes specialized cells with extensions (pedicels) that cover the glomerular capillaries
Visceral layer
Bowman’s capsule:
_____-podocytes specialized cells with extensions (pedicels) that cover the glomerular capillaries
Visceral layer
podocytes specialized cells with extensions (pedicels) that cover the glomerular capillaries. These projections interdigitate to form filtration slits, leaving small gaps to form a sieve. As blood passes through the glomerulus, 10 to 20 percent of the plasma is filtered as it passes between these filtration slits to be captured by the lumen of ______
Bowman’s capsule.
Bowman’s capsule
Liquid inside the lumen of the nephron is known as _____
filtrate.
______-receives filtrate from Bowman’s capsule.
o It is called convoluted due to its tortuous path.
o Simple cuboidal cells form this tubule with prominent microvilli on the luminal surface, forming a brush border.
Proximal convoluted tubule (PCT)
What does the Microvilli in Proximal convoluted tubule (PCT) due?
create a large surface area to maximize the reabsorption and secretion of solutes (Na+, Cl–, glucose, etc.), the most essential function of this portion of the nephron.
____-actively transport ions across their membranes, so they possess a high concentration of mitochondria in order to produce sufficient ATP.
microvilli
____-receives filtrate from PCT.
*o Consists of an initial short, thick portion with a simple cuboidal epithelium and long, thin portion with a simple squamous epithelium
Descending limb of the loop of Henle
____-receives filtrate from descending limb after a hairpin turn.
o Consists of an initial short, thin portion with a simple squamous epithelium and long, thick portion with a simple cuboidal epithelium.
Ascending limb of the loop of Henle
____-receives filtrate from ascending limb of the loop of Henle.
Distal convoluted tubule (DCT)
_____-is very tortuous and formed by simple cuboidal epithelium, but it is shorter than the PCT
The DCT, like the PCT
o Filtrate from the DCT flows into the ________ becoming the final urine as it passes through the collecting duct.
collecting duct
_______- the initial part of the distal convoluted tubule (DCT) comes into direct contact with the afferent arteriole near the renal corpuscle.
Juxtaglomerular apparatus (JGA)
Juxtaglomerular apparatus (JGA): \_\_\_\_\_-The wall of the DCT at that point forms a part of the JGA. This cluster of cells monitors the composition of fluid flowing through the DCT. In response to a change in the concentration of Na+ in the fluid flowing past them, these cells release paracrine signals. They also have a single, nonmotile cilium that functions as a receptor to detect the rate of fluid movement in the tubule.
Macula densa
Juxtaglomerular apparatus (JGA): \_\_\_\_\_-modified, smooth muscle cells lining the afferent arteriole that forms part of the JGA. Responds to paracrine signals from macula densa.
Juxtaglomerular cells
_____-transport of substances from the filtrate into the blood.
o About 99 percent of the water and most of the solutes filtered by the nephron must be reabsorbed
Reabsorption
____-transport of substances from blood into the filtrate.
o Waste and toxins are secreted.
Secretion
what hormone does the kidney produce
Erythropiesis
