Physiology 1 Flashcards
How many nephrons does each kidney have?
1 million
When do nephron number start reducing?
30
Consequences of high potassium?
V Fib (and death)
Consequences of low potassium?
Weakness and malaise
What does the kidney seek to regulate ahead of all else?
Water and Sodium
Two hormones secreted from the kidney?
Renin
Erythropoitin
What vitamin is secreted from the kidney?
What is its role?
Vit D3
Calcium re-absorption from the gut
What prostaglandin is secreted by the kidnye?
PGI2 (prostacyclin)
- This lowers blood pressure it is a vasodilator
What is the filtration unit of the kidney called?
The glomerulus
Where is the initial filtrate from the kidney formed?
Bowman’s capsule
What are the size of the holes in the capillaries in Bowman’s capsule?
2nm slits
What prevents some molecules from moving through the capillaries in a healthy kidney?
Negative charge on the filtration slits which repels negatively charged ions.
This also allows some bigger positively charged proteins to get into the filtrate
What is the most important negatively charged protein which is not filtered by the kidney?
Albumin
What is the GFR per day and minute?
180L/day
125mls/min
= 60nL/min (per nephron)
What is a feature of the proximal tubule?
It is convoluted (to give it extra length)
What is the order of the segments of the kidney?
- Bowman’s capsule
- Proximal Tubule – pars recta and PCT (convoluted tubule)
- Thin descending limb of Henle’s Loop – tDLH
- Thin ascending limb of Henle’s Loop – tALH this is very short in superficial cortical nephrons It is long in JM nephrons
- Thick Ascending limb – TAL
- Distal Tubule –DT
- Collecting Duct – CD
What percentage of kidneys have a loop of Henle which delves into the medulla?
85% only delve to a shallow degree (short loops of henle)
15% have long nephrons which go down to the very tip of the medulla (the papilla)
What happens are the junction between the ascending limb of the loop of Henle and the distal tubule?
Makes contact with its home glomerulus
It occurs in the crevice between the afferent and efferent arterioles
What is the contact point between the between the ascending limb of the loop of Henle and the distal tubule as well as the glomerulus called?
Macula densa