Structure & Function Flashcards
Where are the kidneys found?
Retroperitoneal
L = T12 – L3
R = T12/L1 – L3/4
Each about 150g
What is the functional unit of the kidney?
nephron
What is the blood supply to the kidney?
Renal artery enters the hilar region and splits to form the anterior and posterior branch
What is a nephron made up of?
Glomerulus = tuft of capillaries between an afferent and efferent arteriole
Tubule = starting with bowmans capsule, PCT, LoH, DCT, collecting duct
What is the ureter vs the urethra?
Ureter = smooth muscle, from kidney to bladder
Urethra = bladder to external
Where do the ureters lie?
Tips of transverse process
On top of lumbar lumbora
Ascend down the tips of lumbar processes
Over the edge of the pelvic bowl
Enter the bladder posteriorly
Where do structures enter and leave the kidney?
kidney hilum
ureter, renal artery/vein
What are the layers of the kidney?
Cortex = outer
Medulla = inner, organised in pyramids that contain collecting ducts
Calxys = collect urine
Pelvis = where urine leaves the kidney
Describe the medulla of the kidney
innermost part of the kidney
split up into a number of sections = renal pyramids
What is the cortex off the kidney?
outer portion of the kidney between the renal capsule and the renal medulla
What are renal pyramids?
form the kidney medulla
pyramids appear striped because they are formed by straight parallel segments of nephrons and collecting ducts
Which kidney is lower and why?
Right
Due to liver
What is the bladder?
Bag of smooth muscle that stores urine
Outline the blood supply of the kidney
A = renal artery - abdominal aorta
V = renal vein - IVC
What are the functions of the kidneys?
Regulation = control conc of key subs in ECF
Excretion = excretes waste products
Endocrine = synthesis of renin, erythropoietin, prostaglandins
Metabolism = active form of Vitamin D, catabolism of insulin, PTH calcitonin
How is Vit D linked to the kidneys?
Healthy kidneys are rich with vitamin D receptors
Turns vit D into its active form calcitriol = helps balance CA and phosphorus and regulates PTH
Outline the volume of the body fluid compartments
70kg human = 60% water
42L water = 14L ECF + 28L ICF
14L ECF = 11L interstitial water + 3L plasma (circulating blood volume = 3L plasma + 2L RBC)
What is osmolarity vs osmolality?
Osmolality –is solute per kilogram of solvent
Osmolarity – number of osmoles of solute per litre
What is an osmole?
Measure of the ability to attract water
Proportional to the number of osmotic particles formed in solution
What is the role of the renal pelvis?
funnel-like dilated proximal part of the ureter in the kidney
funnel for urine flowing to the ureter
What is the function of the major and minor calyx?
Urine passes through a renal papilla at the apex into the minor calyx
two or three minor calyces converge to form a major calyx, continuing through the renal pelvis into the ureter
What is the renal papilla?
location where the renal pyramids in the medulla empty urine into the minor calyx in the kidney
What happens to a cell in an isotonic solution?
No net gain/loss of water
What happens to a cell in a hypotonic solution?
Fewer osmolar particles
Water moves into cell
What happens to a cell in a hypertonic solution?
Water moves out of the cell
Outline the intra vs extra cellular electrolyte compositions
Intracellular high K+, low Na+, many large organic anions
Extracellular low K+, high Na+, main anion Cl- and HCO3-
Outline what happens when there is a failure to control the EC volume
Changes in BP, tissue fluid, cell function
Failure to control ECF osmolarity = cell shrink/swell
Where is the prostate located?
between the bladder and the penis, anterior to the rectum
Where does the bladder lie?
Posterior to the pubic bones and pubic symphysis
When full = may reach as high as the umbilicus
What shape is the bladder when it is full vs empty?
Empty = tetrahedron
Full = spherical
Outline the musculature of the bladder
Detrusor muscle = smooth muscle running = transversely, longitudinally, obliquely
What are the sphincters of the bladder?
Internal = involuntary, circular detrusor muscle
External = voluntary striated detrusor muscle
What allows the bladder to expand?
rugae
Where does the ureter pierce the bladder?
Posterior surface
How does the journey of the ureter differ in males to females?
M = passes under ductus deferens, superior to seminal vesicles
F =posterior to ovary, passing under uterine artery
What is a nephron?
Functional unit of the kidney
regulating the concentration of sodium salts and water by filtering the kidney’s blood, excreting any excess in the urine and reabsorbing the necessary amounts
In what part of the kidney is the proximal convoluted tubules found?
Cortex
In what part of the kidney is the loop on henle found?
Dips in and out the medulla
In what part of the kidney is the distal convoluted tubule found?
Cortex
In what part of the kidney is the collecting duct found?
Passed through medulla to pelvis
In what part of the kidney is the glomerulus found?
Cortex
Why is the proximity of the glomerulus and the DCT important?
Allows communication between the two
Briefly outline the function of the nephron
Glomerulus = filters ECF
PCT = reabsorb nearly everything (lots of mitochondria)
Loop of henle = creates conc gradient, fluid leaving is hypotonic
DCT = active, region of choice, removes more Na Cl
Collecting duct = collection of urine to be passed to pelvis, responsive to ADH
What factors are reabsorbed in the kidneys?
99% water
99% Na, Cl
100% bicarb
100% glucose, AA
What factor enables the tubules to reabsorb?
Lined with epithelial cells = polarised = different transporters each side
Basolateral mem (ECF) = 3Na/2K ATPase creates gradient
Luminal mem = cotransporters uses gradient
What types of pumps are on the luminal membrane?
Na = secondary active transport, Na enters down conc gradient, energy released drives glucose reabsorption
What is intravenous urogram?
radiological procedure to visualize abnormalities of the kidneys, ureters, bladder
uses contrast
What is the diff between para-renal and peri-renal fat?
para = superficial to the renal fascia
peri = between the renal fascia and renal capsule
