Urinary System Flashcards
The urinary system consist of the…
kidneys, ureters, bladder, and urethra
Homeostasis
relatively constant state of the body’s internal environment
During embryonic development, temporary kidneys, called ________, develop
mesonephros
Mesonephros function as kidneys until what week?
8th
The mesonephros use mesonephric ducts to transport urine to a collection area called the…
cloaca
While the mesonephros are functioning, another pair of kidneys (called ___________) are developing near the embryo’s caudal end
metanephros
___________ ______ extends from the mesonephric ducts (near their attachment to the cloaca) to meet up with the developing metanephros
ureteric buds
The ureteric buds branch out into the tissue of the metonephros and are then referred to as…
metanephric ducts
During the 8th week of development, the ___________ take over the kidney function and become the permanent kidneys
metanephros
As the embryo grows in length, the kidneys assume a more ______ position in the abdomen
superior
The intermediate mesoderm gives rise to…
the kidneys
Bilaminar Disc
2 plates of tissue of embryo
- top plate = epiblast
- bottom plate = hypoblast
At the 18th day of development, the bilaminar disc becomes the trilaminar disc, which consists of the…
ectoderm, mesoderm, endoderm
The urogenital sinus is the…
developing bladder
Where are the kidneys located?
against the posterior wall of the upper abdomen (one on each side of the vertebral column)
Kidneys are surrounded by a large amount of…
fat
Kidneys have a dense connective tissue covering called the…
renal capsule
What are the main excretory organs?
the kidneys
Gluconeogenesis
synthesis of glucose from amino acids
The urinary system secretes erythropoietin to stimulate..
red blood cell production
The medial border of the kidney has an indentation called the ______ ______, where the renal artery enters and the renal vein and ureter leave
renal hilus
Which renal vein is longer, the left or the right?
left
Which kidney is lower, the left or the right?
right
Three distinct regions can be distinguished inside each kidney. What are they?
cortex, medulla, pelvis
What is the outer layer of the kidney?
the cortex
Deep to the cortex of the kidney is the…
medulla
The medulla of the kidney is divided into…
pyramid shaped regions by penetrating cortical columns
At each apex of a pyramid in the kidney, there is a __________, which expels the urine being produced.
papilla
The papilla of each pyramid projects into a small, cup-like space called a…
minor calyx
Several minor calyces join together to form a…
major calyx (3-5 per kidney)
The major calyces join together to form the ______ ______, which transports urine to the ureter and onto teh bladder
renal pelvis
The ureter, blood vessels, etc. of a kidney lie in a hollow chamber called a…
renal sinus
Kidneys receive what percent of cardiac output?
20-25%
Each kidney is typically fed by a single _______ ______, but it is not uncommon to find multiple.
renal artery
Each renal artery divides into how many segmental branches?
5
Segmental arteries supply blood to…
a functional segment of the kidney
Segmental arteries divide into…
interlobar arteries (a lobe is a pyramid and associated cortex)
An interlobar artery courses along the base of a pyramid as an…
arcuate artery
Arcuate arteries give rise to…
cortical arteries (which penetrate the cortex)
Cortical arteries give rise to…
afferent arterioles (which feed glomeruli)
Once blood passes through a glomerulus, it leaves through an…
efferent arteriole
What is the functional unit of the kidney?
nephron
There are approximately how many nephrons in the kidneys combined?
2.5 million
The nephron has 5 main parts:
capsule proximal convoluted tubule nephron loop distal convoluted tubule collecting duct
The nephrons form urine through…
filtration, tubular reabsorption, and tubular secretion
What is the non-selective, passive process by which water and solutes in the blood plasma move out of the glomerulus and into the capsule (due to pressure)?
filtration
Tubular reabsorption is…
the active transport of substances from the tubular fluid back into the bloodstream
Tubular secretion is…
the active transport of solutes from the blood into the tubular fluid
What is the movement of fluid in the nephron?
- glomerulus
- capsule
- proximal tubule
- nephron loop
- distal tubule
- collecting duct
Filtrate
fluid in the capsular space as a result of filtration
Reabsorption
movement of fluid from the tubule into the bloodstream
Secretion
movement of fluid from the bloodstream into the tubule
Renal Corpuscle
glomerulus + glomerular capsule
- the bulbous end of the nephron
The outer wall (parietal layer) of the renal corpuscle is composed of…
simple squamous epithelial cells
The inner wall (visceral layer) of the renal corpuscle) is composed of…
podocytes
Where is the capsular space located in the renal corpuscle?
between the visceral and parietal layers
The filtration membrane of the renal corpuscle consists of…
the simple squamous cells of the glomerulus and the visceral layer of the capsule
The proximal convoluted tubule is comprised of…
simple cuboidal cells with tall microvilli
Does the proximal convoluted tubule have a high or low mitochondria count?
high
Function of the proximal convoluted tubule
actively reabsorbs nutrients (glucose and amino acids), ions (especially sodium), vitamins and plasma proteins from the filtrate back into the bloodstream
The thick part of the nephron loop is made of…
simple cuboidal cells
The thin part of the nephron loop is made of…
simple squamous cells
Function of the nephron loop
reabsorb ions (sodium and chloride) missed by the proximal convoluted tubule
The distal convoluted tubule is comprised of…
simple cuboidal cells with sparse microvilli and mitochondria
Function of the distal convoluted tubule
- secrete ions (such as potassium and hydrogen) into tubular fluid
- reabsorb water (under the influence of antidiuretic hormone and aldosterone) in response to low blood volume
If you want to increase your blood pressure, what do you want urine to do?
be reabsorbed into the bloodstream, concentrating the urine so you don’t get rid of more water
What is the juxtaglomerular apparatus?
where the distal convoluted tubule and afferent arteriole come into physical contact
What does the distal convoluted tubule monitor in the juxtaglomerular apparatus?
- how much water is in the tubule
- how much pressure is in the afferent arteriole
- the distal convoluted tubule will respond to retain water if the water content is low (low BP)
Ureters
fibromuscular tubes that carry urine from the kidney to the bladder
The ureters have a mucosa lined by…
transitional epithelium
The muscular layer of the ureters consists of…
longitudinal and circular smooth muscle
The adventitia of the ureters is formed from..
areolar connective tissue
The ureters project into the bladder such that a _____ is formed to prevent backflow.
valve
Urinary Bladder
muscular pouch that stores urine and actively expels during urine
The mucosa of the bladder is lined by…
transitional epithelium
The muscular wall of the bladder is called the…
detrusor
What structure conducts urine out of the bladder?
the urethra
The internal urethral sphincter is __________ muscle that prevents urine flow
smooth (involuntary)
The external urethral sphincter is ________ muscle that prevents urine flow
skeletal (voluntary)
Renal Calculus
a kidney stone.
- most are made from calcium oxylate, and they create jagged crystalline formations that can become lodged at various sites along the urinary tract.
During the storage of urine, the _________ ________ _________ is contracted and the ______ is relaxed (the result of sympathetic activity)
internal urethral sphincter ; detrusor
When there is sufficient urine in the bladder, ________ _______ in the bladder wall send signals to the micturition reflex center of the brain, which activates the parasympathetics.
stretch receptors
Parasympathetic activity causes the internal urethral sphincter to _____ and the detrusor to ______
relax ; contract
Micturition Reflex
controls urine storage and elimination in newborns
What is achieved in potty training?
the child learns to over-ride the micturition reflex until a more convenient time/place to urinate
- activates the external urethral sphincter. you contract this muscle when you sense urine in the bladder and do not want to expel it.