Renal Physl 1-3 Flashcards
What is the urinary system comprised of?
The kidneys and associated structures
Where are the kidneys found?
In the posterior abdomen behind the peritoneum on either side of the spine
How long is each kidney?
About 10cm long
What is each kidney supplied with?
A neurovascular bundle
What does the neurovascular bundle consist of?
The renal arteries, veins, nerves, lymphatics and the ureter
What do the ureters drain into?
The urinary bladder
What reflex does the bladder use to contract?
The micturition reflex
What occurs during the micturition reflex?
The muscular bladder contracts to push urine through the urethra where it can then leave the body
Where does the urethra pass through in males?
The urethra passes through the prostate gland and is located within the shaft of the penis
What does the female urethra serve as a conduit for?
Exclusively for urine unlike males
Why can bacteria enter the female urethra more easily?
Because of its shorter length and close location to the anus
Which side of the kidney has a dip?
The medial side that faces the spine
What is the dip in the kidneys known as?
The renal hilum
Which vessels enter and leave at the renal hilum?
The renal artery enters the kidney and the renal vein leaves. Lymphatic vessels and nerves also track along the renal vessels. The ureter also emerges from the renal hilum
What does the ureter do?
Conducts urine down to the bladder
What are the kidneys covered in?
A tough fibrous capsule
What does the tough fibrous capsule surrounding the kidneys do?
Protects the delicate inner structure of the kidney while facilitating hemodynamic functions
What are the two key regions on the inside of the kidney?
The inner medulla and the outer cortex
What is the medulla divided into?
Cone shaped regions called renal pyramids
Where is the wide base of each pyramid located?
At the border between the cortex and the medulla
What does the narrow top of each pyramid end in?
A strucuture called the pepilla
What do the renal papilla project to?
The upper end of the ureter called the renal pelvis
What does urine from each papilla drain into?
Pouches called minor calyces that join into major calyces
What borders the renal pelvis?
The major calyces
What does the structural tissue of the calyces and renal pelvis feature?
Contractile elements that exhibit rhythmic contractions that serve to push urine down towards the bladder
What part of the kidneys has contractile tissue?
The calyces of the renal pelvis and the ureter
What percent of cardiac output does the kidneys receive?
22%
What does the renal artery branch into once it enters the hilum in order?
- Interlobar arteries
- Arcuate arteries
- Interlobular arteries
- Afferent arterioles
- Glomerular capillaries
- Efferent artierioles
What blood vessels arise from the Glomerular capillaries?
Efferent arterioles
What capillary bed does the efferent arterioles form?
The peritubular capillaries
What are the characteristics of the capillary beds in the kidneys?
The kidneys contain two capillary bed in series
What do the peritubular capillaries drain into?
Interlobular veins
What is the order of blood vessels form the glomerular capillaries?
- Efferent arteriole
- Peritubular capillaries
- Interlobular veins
- Arcuate veins
- Interlobar veins
- Renal vein
What is the functional unit of the kidney?
The nephron
What percent of each type of nephron is located where?
80% of nephrons are located within the cortex and the remaining 20% begin at the border of the cortex and the medulla
What are the characteristics of the 20% of nephrons that begin at the border of the cortex and medulla?
They have long tubules which project deep into the medulla
What are cortical nephrons?
Nephrons located in the cortex
What are juxtamedullary neurons?
The 20% of neurons that extend into the medulla
What do peritubular capillaries surround?
The renal tubules
What is unique about the peritubular capillaries in juxtamedullary nephrons?
They are longer and more specialized
What is the vasa reca?
The peritubular capillaries that surround the renal tubules
What is the first part of a nephron?
The Bowman’s capsule
What does the Bowman’s capsule surround?
Tthe glomerular tuft
What is the Renal Corpuscle?
Bowman’s capsule + glomerulus
What enters Bowman’s capsule?
Fluid filtering from the capillaries
What is the endothelium of the glomerular capillaries fused with?
The epithelium of Bowman’s capsule
What does the fusion of the endothelium of the glomerulus with the epithelium bowman’s capsule do?
Ensures that any fluid that filters out of the the capillaries flow directly into bowman’s capsule and into the lumen of the tubular portion of the nephron
What happens once fluid enters Bowman’s capsule?
It flows through successive segments of the renal tubules
What is the order of flow from the Bowman’s capsule?
- Proximal tubule
- Loop of henle
- Distal tubule
- Collecting duct
- Renal pelvis
- Ureter, bladder, urethra
What does the ascending portion of the loop of henle feature?
Thick and thin segments
What does the collecting duct transverse?
The medulla
What meets at the collecting duct?T
Filtrate from multiple nephrons
Where do the collecting ducts drain into?
The renal pelvis which drain into the renal medulla
What does the ascending limb of the loop of henle pass between?
The afferent and efferent arterioles
What is the juxtaglomerular apparatus?
The ascending portion of the loop of henle that passes through the afferent and efferent arterioles
Describe the tubular wall?
- Epithelial cells
- Connected by tight junctions
- Apical and basolateral surface
What are the features of the apical surface of the tube?
It faces the tubular lumen (renal interstitium) and forms microvilli
What does the basal end of the epithelial cells rast on?
The basement membrane
What is the Renal interstitium?
The space surround the nephrons and the peritubular capillaries
