Summary Physiology Basic Concepts Kidney

PHYSIOLOGY BASIC
CONCEPTS
Kidneys


Summary
Summary of the course ‘Physiology Basic Concepts’ second part; Kidneys.
All the lectures are in this summary.




Carlita Verhoef


, Physiology Basic Concepts | Carlita Verhoef



Inhoud
K01 Anatomy Urinary System ............................................................................................. 2
K02 Basic Concepts in Renal Physiology........................................................................... 8
K03 Regulation of renal plasma flow (RPF) and glomerular filtration rate (GFR) ........... 13
K04 Pt and Loop of Henle ................................................................................................. 17
K06 Distal Nephron ........................................................................................................... 21
K09 Osmoregulation ......................................................................................................... 27
K10 Volume Regulation .................................................................................................... 33
K12 Acid, Base, Buffers .................................................................................................... 39
K13 + K14 Acid-Base Regulation ..................................................................................... 42
K15 + K16 Potassium ....................................................................................................... 50
H01 Acid-Base Balance .................................................................................................... 60
H02 Volume regulation and osmoregulation .................................................................... 66




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, Physiology Basic Concepts | Carlita Verhoef




K01 Anatomy Urinary System
The kidneys have some essential function;
 Conserve body fluid and electrolytes and remove metabolic waste
 Regulate water- and electrolyte balance, tissue osmolality, blood pressure, acid-base
balance
 Function also as an endocrine organ: synthesis and secretion of erythropoietin (bone
marrow erythropoieses) and renin (blood pressure), causes activation of vitamin D
(Ca2+ metabolism)
The kidneys are high in the upper abdomen. The left kidney is a little bit higher in the upper
abdomen than the right one. This is caused by the liver, which is also on the right side. The
kidneys have no other relationship with other organs; this is why they are primary
retroperitoneal. The kidneys are surrounded by:
 Perinephric fat; perirenal fat capsule = structural adipose tissue
 Renal fascia; enclosing membranous layer, open inferiorly; also encloses the
suprarenal gland
 Paranephric fat; pararenal fat body = retroperitoneal adipose tissue
The left renal artery is shorter than the right renal artery. The opposite holds for the vein. The
renal vein on the left side is longer, than on the right side because the right kidney is much
closer to the vena cava inferior.
Left renal vein: receives the left suprarenal vein and gonadal (testicular/ovarian) vein.
Clinical: renal vein entrapment syndrome; compression of the left renal vein between
the superior mesenteric artery anteriorly and abdominal aorta posteriorly.
The kidneys have a bean shaped, multilobes structure. They concave medially and
have a renal hilum (entrance). The renal hilum contains the vein (anterior), artery
(middle) and the renal pelvis (posterior). The renal pelvis is the urine collection system,
which transfers into the ureter. It also has autonomic nerves and lymphatic vessels.
The suprarenal gland is a separate organ that produces corticosteroids.
The fibrous capsule has 2 layers
(fibroblast, myofibroblasts); aids in
resisting volume and pressure
variations.
The kidney receives 25% of the
Cardiac Output. It is branched in 5
segmental arteries which are divided
in interlobular arteries. In the
medulla, it has an arcuate artery. In
the cortex; 90-95% of the blood is
present in the renal cortex.




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, Physiology Basic Concepts | Carlita Verhoef




The nephron is the structural and functional unit of the kidney. It is situated in the cortex and
the medulla. The renal corpuscle (of malpighi) has two components; clomerulus and
Bowman’s capsule. The general organization of the nephron is as followed;
 Proximal thick segment;
 Proximal convoluted tubule (TC I)
 Proximal straight tubule (TR I)
 Thin segment
 Thin part of the loop of Henle
 Distal thick segment
 Distal straight tubule (TR II)
 Distal convoluted tubule (TC II)
The collecting tubule is outside of the nephron and contains the ductus colligens and
ductus papillaris. The thin segment is followed by a distal thick segment. This part goes to
the duct. On the distal convoluted tubule, less microvilli are present
Renal corpuscles;
 Always in the cortex (cortical labyrinth and renal columns); subcapsular, intermediate
and juxtamedullary
 Juxtamedullary nephrons have long loops of Henle*
Loop of Henle
 Pyramidal part proximal straight tubule (TR I)
 Thin segment
 Pyramidal part distal straight tubule (TR II)




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