The Kindeys Flashcards
Name the 10 parts of the kidneys
1) Adrenal cortex
2) Adrenal medulla
3) Renal pelvis
4) Renal medulla
5) Renal Pyramid
6) Renal Artery
7) Renal Vein
8) Renal Capsule
9) Nephron
10) Ureter
Name the 7 parts of the nephron (in the order)
1) Glomerulus
2) Bowman’s capsule
3) Proximal convoluted tubule (PCT)
4) Loop of Henle
5) Distal convoluted tubule (DCT)
6) Collecting duct
7) Ureter
What is excretion
The removal of metabolic waste from the body
Name 4 excretory organs
1) Kidney
2) Lungs
3) Skin
4) Leaf
What substances are excreted from the kidney
(What structures do they involve and why is it important)
Substances excreted: Urea, excess water, excess minerals (salt)
Structures involved: nephrons, bladder
Importance: removal of toxic substances
What substances are excreted from the lungs
(What structures to they involve and why is it important)
Substances excreted: CO2 and water vapour
Structures involved: alveoli
Importance: to allow oxygen to enter the blood
What substances are excreted from the skin
(What structures to they involve and why is it important)
Substances excreted: Sweat (salt water)
Structures involved: Sweat glands
Importance: homeostasis, thermoregulation
What substances are excreted from the leaf
(What structures to they involve and why is it important)
Substances excreted: O2, CO2, water vapour
Structures involved: stomata, guard cells, xylem
Importance: human respiration
How would you describe the cortex
Anything in the upper section
How would you describe the medulla
Anything that spans downwards
What are the Malpighian bodies
A collective name for the Glomerulus and the Bowman’s capsule
What structures can you find in the kidney’s cortex
1) Proximal convoluted tubule
2) (some of the) Distal convoluted tubule
3) Malpighian bodies
What structures can you find in the kidney medulla
1) Loop of Henle
2) (some of the) Distal convoluted tubule
3) Collecting duct
What are the functions of the kidney
1) Excretion of waste products (main function)
2) regulate waste products, ions and water in the bloodstream
What is the first stage in excretion
Ultrafiltration
What is ultrafiltration based on
Size
What are the two blood vessels involved in ultrafiltration
1) Afferent arteriole vessel
2) Efferent arteriole vessel
Describe the characteristics of the afferent arteriole vessel
- wider
- bring blood into the glomerulus
- it is at a high pressure
Describe the characteristics of the efferent arteriole vessel
-narrower (so blood in the glomerulus is under high pressure)
-carries blood away from the glomerulus
-high pressure but lower than afferent arteriole
Explain why we need a build up of pressure between the afferent and efferent arterioles (bottleneck effect)
It allows for a larger volume of blood to be taken in so more blood can be filtered. The high pressure forces liquid and small molecules in the blood into the Bowman’s capsule.
What is the pressure value that allows for filtration to occur
> 6.7kPa
What are the three layers that the liquid and small molecules have to pass through to get into the Bowman’s capsule
1) Endothelium capillary: small gaps/pores that allow for small molecules to pass through
2) Basement membrane: membrane made of collagen fibres and glycoproteins that stops things (blood cells, proteins etc) leaving the glomerulus
3) Epithelium of the Bowman’s capsule (podocytes): have extensions (pedicels) ensuring gaps between the cells for fluid from glomerulus into the lumen of Bowman’s capsule
At the end of ultrafiltration what is the filtered substances called
Filtrate
What things are filtered from the Glomerulus into the Bowman’s capsule
- Water
- Amino acids
- Glucose
- Urea
- Inorganic ions
How small do these molecules have to be to be filtered out
Have to have a relative molecular mass (RMM) of 69,000
What are left in the capillary
-blood cells
-proteins
Why does water potential in the capillaries become negative? How is this helpful
Because water is moved into the capillaries. helps with reabsorption of water
What is selective reabsorption
Reabsorbing useful molecules back into the blood
What part(s) of the nephron is involved in selective reabsorption
PCT (mainly) but also the DCT
What molecules do we reabsorb back into the blood
- Glucose= used for respiration
- Water
- Amino acids
- inorganic ions
What molecule do we never reabsorb back into the blood and why
UREA!!
- as it is toxic
What on the PCT provides a large SA
The epithelium wall having microvilli
Describe the mechanism of selective reabsorption
1) sodium ions are actively pumped out of the cell lining the tubules
2) concentration of sodium ions in the cell cytoplasm decreases, creating a concentration gradient
3) sodium ions diffuse into the cell through cotransport proteins which also carry glucose or amino acids at the same time
4) water moves into the cell by osmosis (since there is a decrease in the water potential with all the solutes moving in)
5) glucose/amino acids diffuse into the blood