Exam3Lec2FiltrationClearance Flashcards
List the functions of the Kidneys (7)
- Remove wastes
- Regulate volume and compositon of ECF
- Acid-base balance
- Blood Pressure Regulation
- Removal of Foreign Substances
- RBC productin
- Vitamin D activity
Which vessels provide the vascularture for the kidneys?
- Blood goes to the kidneys through the renal artery
- Blood leaves the kidneys through the renal vein
What is the functional unit of the kidneys?
Nephrons (2 types)
What are the 2 types of nephrons in the kidneys and what are their locations?
- Cortical nephron: close to the kidney surface (cortex)
- Juxtamedullary nephron: Interphase between the cortex and medulla
Juxtamedullary nephron has longer loops up the tubule than cortical nephron
List the three types of capillary beds located in the kidneys
- Glomerular capillaries
- Pertiubular capillaries
- Vasa recta
Capillary beds are located between the renal artery and vein
Where can you find glomerular capillaries in the kidneys?
Can be found in BOTH cortical nephron and juxtamedullary nephron
How do glomerular capillaries enter and exit the glomerulus and explain their function?
- Enters through afferent arterioles, Exits through efferent arterioles
- Function: Plays a major role in the filtration process d/t the different diameters of the afferent (bigger) and efferent (smaller) arteriole.
Different in diameter sizes drive the filtration process
Where can you find peritubular capillaries in the kidneys?
Can be found in BOTH cortical nephron and juxtamedullary nephron
How are the peritubular capillaries formed and explain their function?
- Derived from the efferent arterioles which bifurcate and wrap around the tubules
- Function: Absorption- able to do 2 way transport between the tubules and capillaries because of very close proximity between the two
Where can you find the vasa recta in the kidneys?
Can ONLY be found in the juxtamedullary nephron
How is the vasa recta formed?
- Derived from efferent arterioles and have 2 components
- Descending vasa recta
- Ascending vasa recta
What is a major difference between the peritubular capillaries and the vasa recta?
- Vasa recta ara far away from the tubules compared to peritubular capillaries which are very close
- So ecxhange of substances between tubules CANNOT happen in vasa recta
Exchange of substances CANNOT occur from the vasa recta and kidney tubules. Where in the vasa recta CAN exchange occur?
Exchange of substances between the descending vasa recta and ascending vasa recta
How much of the blood flow to the kidneys goes the the vasa recta?
10%
Which nervous system innervates the Kidneys?
Sympathetic Nervous System
Part of the ANS
What parts of the kidney receive sympathetic innvervation?
- Afferent and Efferent Arterioles
- Juxtaglomerular cells
- Tubule
What sympathetic actions occur from the parts of the kidneys that recieve SNS inneravation?
- Afferent and Efferent Arterioles
- Juxtaglomerular cells
- Tubule
- Afferent and Efferent Arterioles: Control Vascular resistance
- Juxtaglomerular cells: (modified SMC around afferent arterioles) ↑ secretion of the enzyme Renin
- Tubule: ↑ Reabsorption
Renin is located in granules in the juxtaglomerular cells
What are important cellular components of the proximal tubule of the nephron? (2)
- Has brush borders (microvilla) for large surface area to help w/ absorption
- Has many mitochondria to generate ATP to provide energy for absorption
Explain the cellular components of the thin descensing and ascending limb of the nephron
Has few mitochondria, little active transport (mainly passive)
Other segments of the nephron have many _______ and other organelles
mitochondria
List the 3 processes of Urine Formation
- Filtration
- Reabsorption/Secretion
- Excretion
What is the main function of the glomerular filtration process?
Production of a protein-free filtrate of plasma
What are the 3 layers of the glomerulus?
Layers from inner to outer
- Capillary Endothelium
- Basement Membrane
- Bowman’s Capsule Epithelium (podocytes)
Also know as “Three Sieves in Series”
What layer of the glomerulus is the Capillary Endothelium? And explain it’s physical properties and function.
- Layer: Inner Most layer
- Physical property: Many fenestration holes
- Function: 1st layer of the filtration process, highly permeable