Anatomy and Cell Biology 3309 Lecture Notes - Lecture 9: Ice Cream Cone, Renal Pelvis, Renal Medulla
15 May 2018
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Lecture 9 – Urinary System
The nephron
- Filtration device within the kidney
- Blind-ending epithelial tubule that interacts with blood stream, filters blood and evaluates
the contents, gets rid of waste products and recovers things we want to reabsorb
- Production of ultrafiltrate from blood
- Conservation of water, electrolytes and metabolites
- Removal of metabolic waste
- Control of blood pressure
o Regulates volume of urine and blood (relates to BP)
- Approx. 1 million nephrons in each kidney
o Operate independently but globally they communicate to regulate BP
- 1 mL of urine is produced / minute
Kidney anatomy
- Know the different parts of the kidney
- Kidney is a bean shaped organ
- Concave surface is where renal vein and artery enter/leave
- Ureter: epithelial lined tube that opens into the renal pelvis
- Renal pelvis: funnel-like structure of the ureter that collects the urine produced
- Kidney is formed by lobes that are organized in pyramidal form (pyramids)
o Pyramid has apex projecting into the renal pelvis
- Calyx: funnel-like structure where pyramid projects into
o Place where urine is delivered into the ureter
- Human kidneys have many lobes
o Vs. cat only has 1 lobe
- Histological section: D: where pyramid opens into the calyx
- Kidney is divided into outer cortex and inner medulla
o Pyramids are mostly tissue of the medulla
- Each pyramid is like an ice cream cone
o Medulla is the cone and the cortex is the ice cream
o Cortex dips down in between sections of the medulla (called renal columns) → like
ice cream melting
o There is corticol tissue stuck in between pyramids that are mostly made of medulla
- Filtrate is produced in the cortex and delivered through the medulla into the calyx and
ureter
- Kidney is organized into lobes
o Each lobe is like a gland and has lobules
find more resources at oneclass.com
find more resources at oneclass.com
Renal cortex
- Produces filtrate of blood
- Cortex is where the filtrate is produced
- There are ball-like round structures called renal corpuscles
- Renal corpuscles are embedded in various cross sections of epithelial tubules
o Part of the nephrons that is highly convoluted
▪ = weird cross sections: oblique, elongated
o Convoluted tubules surround renal corpuscles
Renal medulla
- Re-absorption of electrolytes and water
- Medulla contains parts of the nephron tubules that run parallel
find more resources at oneclass.com
find more resources at oneclass.com
- In the medulla, nephrons tubules run parallel to one another and depending on the section,
they are either longitudinal or in cross section
- A lot of reabsorption takes place here
o Material is taken out of the filtrate and put back into the blood stream
o There are many blood vessels (capillaries) that run in parallel to the kidney tubules
- Vasa recta: straight capillaries
o Capillaries in the medulla that reabsorb material that is taken out of the filtrate
across the epithelium
- CORTEX: CONVOLUTED TUBULES
- MEDULLA: STRAIGHT TUBULES IN THE SAME DIRECTION
The renal papilla - tip of the pyramid
- Tubules merge and form collecting ducts
- There are many collecting ducts that open independently at the tip of the pyramid
- Tip of the pyramid communicates with the lumen of the ureter = calyx
- Each collecting tubule that delivers urine into the ureter is part of a kidney lobule
- All nephrons that drain their filtrate into one common collecting tubule belong to a lobule
- Whole lobe (pyramid) is made of many lobules
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Blind-ending epithelial tubule that interacts with blood stream, filters blood and evaluates the contents, gets rid of waste products and recovers things we want to reabsorb. Control of blood pressure: regulates volume of urine and blood (relates to bp) 1 million nephrons in each kidney: operate independently but globally they communicate to regulate bp. 1 ml of urine is produced / minute. Know the different parts of the kidney. Concave surface is where renal vein and artery enter/leave. Ureter: epithelial lined tube that opens into the renal pelvis. Renal pelvis: funnel-like structure of the ureter that collects the urine produced. Kidney is formed by lobes that are organized in pyramidal form (pyramids: pyramid has apex projecting into the renal pelvis. Calyx: funnel-like structure where pyramid projects into: place where urine is delivered into the ureter. Human kidneys have many lobes: vs. cat only has 1 lobe. Histological section: d: where pyramid opens into the calyx.
