S2 L1 Glomerulus Flashcards
- *Kidney:**
- what ions/substances are filtered in the kidney?
- what ions/substances are reabsorbed in the kidney?
- What is ultrafiltrate?
- What substances are in the ultra filtrate?
- How much is filtered per day, how much is reabsorbed per day, how much is excreted?
Recap - Body Compartments and there water content
- *Electrolytes:**
- Intra and extra cellular fluids has different electrolyte composition, state electrolyte composition of intracellularly and extracellularly
- How is this maintained?
- Problems if electrolytes are not controlled
- *Water and Osmotic force:**
- Does water cross cell membranes freely?
- What is movement of water driven by?
- Define: Osmolality, osmolarity, oncotic
- *Essential terms:**
- What happens in the glomerulus and bowman’s capsule
- Aim of glomerulus
- Define: Renal blood flow, Renal plasma flow, equation for renal plasma flow, Hmt, Glomerular filtration rate, filtration fraction
Found only in the cortex
• The normal total glomerular filtrate per day is 140 – 180 L /day (~125 ml/min) (GFR)
• Renal plasma flow ~ 600 mL/min
• The filtration fraction (F/F), therefore, represents the proportion of the fluid reaching the kidneys that passes into the renal tubules. It is normally about 20%.
• FF= GFR/RPF
• 20% of blood from renal artery is filtered at any one time
• 80% blood arriving exits via efferent arteriole (unfiltered)
• Always the same despite two types of kidney nephrons: Cortical, Juxtamedullary
Glomerular Filtration rate (GFR):
- Glomerular filtrate normally contains… doesn’t contain… composed of…
The glomerular filtrate normally:
• Contains no blood cells or platelets
• Contains virtually no proteins
• Is composed of mostly organic solutes with a low molecular weight and inorganic ions
Renal corpuscle:
- How to tell the difference between DCT and PCT
- Why this difference?
- How to describe the relationship between glomerulus and DCT
Compare plasma to ultra-filtrate:
- Glucose level
- Na+ level
- Urea level
- Creatinine level
Glomerular capillary membrane
- State what this ‘looks’ like, cells involved
- How is albumin not filtered out of the glomerular (2 reasons)
- Filtration slits in the podocyte
Selectivity of the barrier (basement membrane)
- What molecules can be filtered? Which can’t?
- What is haematuria?
- What is proteinuria?
Which 3 forces determine how much plasma is filtered?
- Where is the net movement?
S______ F_____ govern movement:
- Explain the movement and forces in the first part of the afferent arteriole, middle part and last part of the glomerulus
S______ F______ govern movement:
- Talk about these forces in 3 parts of the glomerulus (first bit, middle, end)
- Hydrostatic (due to water)
- Colloid osmotic (oncotic) pressure (due to protein)
- Net Filtration = PGC – (PBS + !BS) = 50 – (12 + 25)
- Net Filtration = 13mmHg
How does the regulation of renal blood flow and GFR occur?
- 2 ways
Myogenic regulation (PGC is regulated by myogenic…)
- Describe 4 ‘ways’
- Where does it occur most in the kidney
Arterial smooth muscle responds to increases and decreases in vascular wall tension
• It contributes to total auto- regulatory mechanism
• Occurs rapidly (3-10 s )
• It is a property predominantly of the preglomerular resistance vessels: Accurate, Interlobular, Afferent arteriole
Summary of: Myogenic Mechanism
Autoregulation - Further regulation of PGC by Tubular Glomerular feedback (TG-feedback)
- 3 main cells involved and what they do (their role)
Tumbuloglomerular feedback mechanism - High Tubular Flow
Tumbuloglomerular feedback mechanism - Low BP
How to remember - Renin is released by juxtaglomerular cells, in response to the three S’s…
STIMULI: S S S
- Stretch afferent decrease
- Sympathetic
- Signals decreased from macula denSa cells due to decreased NaCl
