Renal System and Nephron Processes Flashcards
Alimentary canal
Also known as the digestive tract, is a long tube of organs that food and liquids pass through as they are digested and leave the body - from the mouth to the anus.
Overall estimates on and water absorption through the intestines
2kg of food and 2L of water is ingested over 24 hours. With the secretions of saliva, bile, gastric juice, pancreatic and intestinal secretions, a total of 9L enters the lumen of the intestines over 24 hours. 7.5L is absorbed into the small intestine, and 1.4L into the large intestine. 0.1L is lost through feces, containing 100ml water. So, nearly the same amount input into the digestive system is input into the blood stream.
Why is consuming 2L of water every 24 hrs needed?
To loosen up feces and properly digest food. But also, to remove cardiovascular waste.
Jejunum
The middle part of the small intestine and the most active site for water absorption.
Ileum
Second site for water absorption in intestines and the end of the small intestine
Colon
Part of the large intestine, which is connected to the small intestine at one end and the anus at the other. It absorbs water against osmotic gradient.
Na+ Absorption
Occurs throughout the intestine, especially colon.
K+ Absorption
Net absorption primarily in jejunum and ileum.
Diarrhea
Causes excessive potassium loss/not ingesting enough potassium. Both effect eachother.
Kidneys
Remove bodily waste via constant filtration. Requires an extra 2L of water every day since the filtration is constant
Filtration Rate
Approximately 180 L of blood filtered daily.
Cardiovascular System relation to kidney function
Transports oxygen, nutrients, and wastes that enter kidneys. Alo transports hormones that control idney function.
The cardiovascular capilliaries also run next to kidney nephrons to provide them with this.
What goes inside the nephron and what remains in the capillaries?
In capilliaries:
* Solid material like red and white blood cells
Into Kidney nephrons:
* Water
* Ions
* Organic molecules - eg Amino acids, vitamins, gluecose
* CO2 and 02 gas
Bowman’s Capsule
First nephron structure receiving filtered plasma.
What type of molecules flow into the Bowman’s capsule?
Plama components:
* Water
* Ions
* Organic molecules
* Trace elements and vitamins
* Gases
Examples of organic materials entering the Bowman’s capsule from the plasma
- Amino acids
- Glucose
- Nitrogenouse watse
- CO2 and O2
Label the parts of the kindey
Control of urination
The bladder has a sphincter surrounded by muscle cells regulated by the nervous system.
Nephron Processes
Includes filtration, reabsorption, secretion, excretion.
Where is the nephron
In the renal cortex
What is the nephron made of?
A single layer of cells
Label this image of the nephron. Label the parts that also are not mentioned
What is the glomerelus made of?
A globular network of renal arteries = golemerular capillaries
4 main processes of the kidneys
Filtration, Reabsorption, Secretion (hormones) and Excretion (of urine)
Where is the loop of henle concentrated?
Due to its length it is mostly in the medulla of the kidneys.
What part of the nephron is thicker?
The distal tube and collecting duct
Gomelular filtration
The plasma filtration here is said to be 100%
Proximal Tubule
Reabsorbs 70% of blood filtrate volume into the renal vein (back into cardiovascular system) = 126L out of 180L
Loop of Henle
Reabsorbs 20% of filtrate volume into renal vein.
Na+, K+, Cl- and Ca2+ ions are also reabsorbed into the lumen from the nephron (green arrow)
Distal Tubule
Reabsorbs 9% of remaining filtrate.
Na+, K+, Cl- and Ca2+ ions are also reabsorbed into the lumen from the nephron (green arrow)
Overall change in reabsorption % through different sections of the nephron
70% ( proximal tube)
20% (loop of henle)
9% (distal tubule)
Excretion
1% of total filtrate is excreted = 1.8L
This is why 2L of water is needed per day, for the kidney to function and filter the blood.
Homeostatic Control
Regulates final 10% of filtrate reabsorption.
Covered more in next deck
Hormonal Secretion
Regulates water and ion balance in kidneys.
Proximal tube secretions
H+ are secreted to acidify urine. Drugs and ureic acid are also secreted. This enables control of water and ions returning into the CVS