Urinary System Flashcards
Functions of the urinary system
Urine production, drainage, storage, and elimination
Regulation of ion balance and water content
Blood pressure stabilization - secretes renin
Elimination, excretion of toxic-end products
Maintenance of the oxygen-carrying capacity of the blood via erythropoietin
Where are all components of the urinary system located?
Retroperitoneal - behind the peritoneum in the abdominal and pelvic cavities
Each kidney is capped by a ______
suprarenal gland (adrenal gland)
Where do vessels and nerves enter the renal sinus of the kidney?
Renal hilus
Rena medulla
Inner region facing the renal sinus
- includes the renal pyramids
Renal Cortex
Outer region that appears granular from the tubules leading to the nephron and large number of renal corpuscles in this region
What is considered a lobe for the kidney?
1 Medullary pyramid plus the overlying cortex
Where is renal produced and where does it drain?
Urine is produced in the renal pyramid and drains to the tip called the renal papilla
- then it drains into the minor calyx, then major calyx, and lastly into the enlarged renal pelvis
What is the enlarged renal pelvis?
The expanded upper portion of the ureter
What structure transports the urine to the bladder?
The ureter
What makes up a major calyx?
2+ pyramids
What is the basic functional and structural unit of the kidney?
The nephron
- 1 million per kidney
What are the functions of the nephron?
Filtration
Excretion
Absorption
What are the components of the nephron components?
Renal corpuscle
Renal Tubule - contains a fluid called tubular fluid (pre-mature urine)
What is the renal corpuscle composed of?
glomerular capillary called the glomerulus
- it’s surrounded by the glomerular (Bowman’s) capsule
Where are the renal corpuscle and proximal convoluted tubule located?
In the Cortex
Is the collecting duct considered part of the nephron?
No
Where does the glomerular capillary (glomerulus) arise from?
From the afferent arteriole
- leaves the renal corpuscle as an efferent arteriole
How does blood enter the kidney?
Via the renal artery
- branches into segmental arteries once inside the hilus of the kidney
What do the renal arteries branch into?
Interlobar arteries
- pass between the medullary pyramids
Where do the interlobar arteries branch into the arcuate arteries?
At the border between medullary pyramid and cortex
- corticomedullary junction
What give rise to the interlobar arteries?
Arcuate arteries
What do the interlobar arteries divide into?
Into the afferent arterioles
What is the purpose of the afferent arterioles?
to bring waste-laden blood into the glomerulus where it is filtered
How does filtered blood leave the glomerulus?
Through the efferent arteriole
What do the efferent arterioles form?
A secondary network of peritubular capillaries
What is the function of the glomerular capillaries?
Extra-efficient filtering
What is the function of the peritubular capillaries?
They surround the tubular system of the nephron and function in resorbing up to 99% of the fluid lost in the glomerulus but leaves the waste in the urine
What is the macula densa?
Tightly packed cells in the wall of the ascending loop of Henle
- sense changes to the blood volume and sends a chemical signal to the juxtaglomerular cells
What do the juxtaglomerular cells do?
Secrete renin which increases water retention
What is the vascular pole of the renal corpuscle?
Where the afferent and efferent arteriole enter and leave the renal corpuscle
What is the urinary pole of the renal corpuscle?
Where the urinary filtrate that enters the filtration space within bowman’s capsule, leaves to enter the tubular portion of the nephron via the proximal convoluted tubule
What layer covers the portions of Bowman’s capsule that forms the outer wall?
Parietal layer of Bowman’s capsule
What layer covers the glomerular capillary?
Visceral layer of Bowman’s capsule
- becomes podocytes
What is the structure of podocytes?
They have many processes that interdigitate with adjacent podocyte processes and completely cover the outside of the glomerular capillary
What is the filtration slit?
The space between the adjacent podocyte processes
What is the filtration barrier?
Where anything filtered from the fenestrated capillary of the glomerulus must cross the fused basement membranes of the podocyte and the cells of the glomerular capillary
What are the three main processes that form urine?
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
Where does tubular reabsorption occur?
proximal convoluted tubule
- cells here have dense brush borders that increase surface area
What is tubular secretion?
A process where substances are transported from the peritubular capillary into the renal tubule and excreted in the urine.
What is the overall path of urine elimination?
- Nephron
- Collecting Duct
- Renal Papilla
- Minor Calyx
- Major Calyx
- Renal Pelvis
- Ureters - transport
- Bladder
- Urethra
Ureters characteristics
Lined by transitional epithelium
- composed of 3 layers: mucosa, muscular, and fibrous coat
What is the mucosa made of?
Transitional epithelium
What is the muscular layer of the ureter?
inner = longitudinal, outer = circular
- helps to move urine towards the urinary bladder using peristaltic waves
What is the fibrous coat of the ureter?
Outer layer of CT that binds it to surrounding tissues
Where are kidney stones formed?
The pelvis of the ureter
What are the four layers of the urinary bladder?
Deep to superficial
- Mucosa - transitional epithelium
- Submucosa - elastic CT
- Muscular layer - smooth muscle, forms of the detrusor muscle
- Serosa/adventitia - parietal peritoneum on the upper wall with fibrous CT on the rest
How does micturition (urination) occur?
Contraction of the detrusor muscle, abdominal wall, pelvic floor, and diaphragm
- internal sphincter must relax (involuntary)
- external urethral sphincter must also relax (Voluntary)
How do male and female urethra differ?
In length
- male is much longer
- female is easier for infection
