Histo Lecture 11

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What are some metaolic wastes that the kidney excretes?

Urea, creatinine, uric acid, bilirubin, hormone metabolites
What are the 3 MAJOR electrolytes the kidney tries to maintain at constant levels in the body?
- H20
- Na+
- PO4-
How does the kidney regulate arterial pressure?

via H2O and Na+
What are the functions of the kidney?
- Excrete metabolic waste
- Matches output with intake for fluid and electrolytes
- Regulates arterial pressure
- Regulates Acid-base balance
- Erythrocyte production
- Regulation of Vitamin D production
- Gluconeogenesis
What does the kidney excrete to signal bone marrow to make erythrocytes?

Erythropoeitin
What are the major landmarks of the kidney?
- Hilum
- Cortex
- Medulla
- Renal pyramid
- Renal papilla
- Renal pelvis
What is the order of arteriole blood supply to the kidney?
- Renal artery
- Interlobar arteries
- arcuate arteries
- interlobular arteries
- afferent arterioles
- glomerulus
What is the functional unit of the kidney?

Nephron
What is the golmerulus?

Tuft of capillaries through which blood is filtered
What is Bowman's capsule?
- Collecting area for initial filtrate
- Distributes fluid to the proximal tubule
What is the tubule system?

tubular network where initial filtrate is conerted into urine
What are the major parts of the nephron?
- Glomerulus
- Bowman's capsule
- Tubule system
- -Proximal tubule
- -Loop of Henle
- -Distal tubule
- Cortical collecting duct
- Medullary collecting duct
What covers the glomerulus?
- Podocytes
- "foot processes" that stretch out over the capillaries
What are the 3 main steps in glomeruluar filtration?
- Reabsorption
- Secretion
- Excretion
What is filtered and secreted into the urine?

Foreign substances
What is filtered and then higly reabsorbed?
- Na+
- Cl-
- HCO3
What is reabsorbed and usually not secreted?

Nutrients
What is GFR?

Glomerular filtration rate
How is GFR measured?

Measured by urine analysis of creatinine clearance from the blood
What is not filtered in urine formation?
- Large proteins
- Negatively charged proteins (albumin, Hb)
- fatty acids
What are the three main things that affect filtration rate?
- CHP
- capsular HP
- capillary OP
Why do people with hypertension have kidney problems?

High blood pressure causes chronic filtration of blood which can "burnout" the glomerulus
How does the sympathetic system control GFR?

Alters afferent and efferent arterioler resistance
What are some vasoconstrictors that decrease GFR?
- epi/norepinephrine
- angiotensin II
- endothelin
What are some vasodilators that increase GFR?
- Nitric oxide
- bradykinin
- Prostaglandins
What is tubuloglomerular feedback?

Sodium concentration at the maula densa controls arteriolar resistance
What is myogenic auto-regulation?
- Reflexive smooth muscle contraction of arterioles (occurs with increased blood pressure/blood flow)
- Increases arteriolar resistance and maintains constant GFR
What does the macula densa "sense"?
- Low NaCl (means increased Na reabsorption)
- High NaCl (means decreased Na reabsorption)
What does the macula densa signal to make changes?

Juxtaglomerular cells to incrase or decrease afferent arteriolar resistance
When there is low NaCl, what happens?
- macula densa signals to decrease afferent arteriole resistance
- kidney releases renin to increase efferent efferent arteriole resistance

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Histo Lecture 11

Description

Renal System

Updated

2011-02-28T21:01:34Z

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