Renal Medicine Flashcards
What organs are in the peritoneal cavity ?
Stomach
Liver
Small intestine
Large intestine (bar the rectum)
Spleen
The kidney is a _______________ organ.
retroperitoneal
exists outside of the peritoneal cavity
located behind the abdomen
What spinal level are the kidneys located in?
T12 - L3
Both kidneys are on the same level. True or false
False
the right one is lower than the left
The renal _______ is both the entry and exit for the kidneys
renal hilum
What surrounds the kidneys?
the renal capsule
Peri-renal fat capsule
renal fascia
What is the function of the urether?
to take urine away from the kidney to the bladder
What is the function of the urethra?
to remove urine from the bladder
Where does urine collect?
urine collects in the pelvis
Blood flow to the cells of the kidney is small. This is due to __________.
capillary size
What maintains the microvasculature of the kidneys?
prostaglandin
For patients with compromised renal function, why should special care be taken when prescribing NSAIDs?
NSAIDs inhibit prostaglandin synthesis
this can compromise microvasculature of the kidneys
What is the function of the bowmans capsule?
filtration of blood from glomerular capillaries
this is one of the first steps to urine synthesis
Arterial supply of the kidneys is supplied by the _________.
renal artery
Venous drainage of the kidneys is performed by ___________.
the renal vein
Where are the adrenal glands located?
“north pole” of the kidneys
Ad- means next to in latin
(Ad)renal- thus adrenal glands are next to the kidneys
Where are donor kidneys usually located?
they are usually located in the pelvis
Give examples of unusual renal anatomy
Horseshoe kidneys (a U- shape; more common in males than females)
Donor kidney
Polycystic kidney
What is a horseshoe kidney?
renal fusion
this is when the two kidneys are fused together
What is the unit of activity in a kidney?
nephron
Briefly describe the blood supply of the nephron
Afferent arteriole (from the renal artery) which then forms the glomerulus; from the glomerulus blood leaves through the efferent arteriole to supply the rest of the nephron
What are the components of the nephron?
Bowmans capsule
glomerulus (specialised bundle of capillaries responsible for filtration of blood)
proximal convoluted tubule
loop of henle
distal convoluted tubule
What is the renal corpuscle ?
blood filtering component of the nephron
consists of bowmans capsule and glomerulus
What is the purpose of the knotted structure of the glomerulus?
causes an increase in pressure
Aside from the knotted structure of the glomerulus, the capillaries of the glomerulus have another quality that facilitates production of urine. What is it?
they are permeable
glomerular basement membrane - separates the podocytes from the endothelial cells and contributes towards selectivity of molecules that can pass through
Small molecules filter out of the glomerular walls into the _____________ in the form of a filtrate
bowmans capsule
Give examples of small molecules that filter out of the glomerulus
water
glucose
ionic salts
ammonia (toxic agent)
Large molecules cannot filter through the glomerulus walls. Give examples of such molecules
Proteins
red blood cells (prevents loss of RBCs and maintains osmotic pressure)
The pressure across the glomerulus is altered by …
the efferent arteriole vasoconstriction or vasodilation
How can you identify the presence of protein in the urine?
upon shaking it becomes frothy
What is the glomerular filtration rate?
volume of blood passing through the glomeruli per minute
amount of filtrate produced per minute
(glomerular filtrate)
What is the path of the filtrate after leaving the renal corpuscle?
Filtrate enters proximal convoluted tubule
Enters loop of henle
continues to the distal convoluted tubule
then enters collecting duct
arrives at the ureter
What is the function of the surrounding vasa recta?
they carry blood to the venules (eventually reaches the renal vein)
Describe what occurs at the loop of henle
1.) water moves out of the descending loop of henle down its concentration gradient and then into the vasa recta
2.) salts are actively pumped out of the ascending loop of henle to make a highly concentrate “salty” medullary interstitium (the interstitial fluid in the medulla)
- ascending loop makes the medulla salty
3.) the concentration of the ultrafiltrate and the interstitium is equal at the base of the loop of henle)
4.) ascending arm of the loop of henle is impermeable to water and thus ultrafiltrate remains concentrated
The collecting duct connects the nephrons to the ________.
pelvis
The collecting duct is prone to _______________ of water
reabsoprtion of water
further concentrating urine
What is the function of the collecting duct? How is this made possible?
water conservation
this is made possible by the loop of henle as it essentially makes the medulla of the kidney “salt” hence water leaves the collecting duct
Renal tubules consist of …
Proximal convoluted tubule
loop of henle
distal convoluted tubule
Renal tubules of multiple nephrons connect to a common ____________.
collecting duct
How is GFR controlled?
vasoconstriction and vasodilation afferent arteriole which controls the glomerular pressure to rise/ fall (respectively)
Capillaries that surround the renal tubules are known as …
peri-tubular capillaries
How is the permeability of the collecting duct regulated?
ADH (anti-diuretic hormone)
cause kidneys to release less water
upregulation of aquaporins present on collecting duct
ADH causes even more water to be reabsorbed in the collecting duct
How are collecting ducts able to allow water to be reabsorbed back into the blood?
they contain aquaporins which are small proteins that open up to allow water to be reabsorbed
What are the functions of the kidney ?
Osmolality homeostasis (ADH)
Reabsorption (water, glucose, amino acids, electrolytes)
excretion (urea, creatinine)
pH balance
blood pressure regulation- renin angiotensin
Endocrine- erythropoietin, vitamin D activation.
Why is kidney disease associated with bleeding disorders?
this is because clotting factors are very pH sensitive (physiological maintenance of pH by kidneys) so pathological changes to kidneys mean that pH balance is disrupted
Disruption of pH balance means that clotting factors will not woek
What is the function of EPO (erythropoietin) ?
stimulated synthesis of RBC in bone marrow
A drop in blood pressure or fluid volume causes the release of __________ from the kidney
renin
the juxtaglomerulus is sensitive to blood flow coming into the glomerulus
What is the function of the renin protein?
renin converts angiotensinogen to angiotensin I
Where is angiotensinogen produced?
liver
Angiotensin I is converted by ______________ to produce angiotensin II
ACE
Angiotensin converting enzyme
Where is ACE produced?
produced in the lungs
What is the function of angiotensin II?
acts on the adrenal glands to stimulate the release of aldosterone (mineralcorticoid in the zona glomerulosa of the adrenal cortex- most superficial layer of the adrenal cortex)
Angiotensin II also acts directly on blood vessels and stimulated vasoconstriction (narrorwing)
this all works to increase blood pressure
What is the function of aldosterone? (include sites of action of aldosterone)
salt retention
acts on the kidneys to stimulate reabsorption of salt (NaCl) and water
Acts on the late distal tubule and the collecting duct, favouring water and sodium reabsorption
List some instances that can lead to a blood pressure drop
loss of fluid
burns
bleeding
Why are ACE inhibitors used to treat heart failure?
in heart failure, the heart is unable to effectively pump blood around the heart.
This can be exarcebated arterial/ venous resistance (vasoconstriction)
ACE inhibitors prevent release of aldosterone which increases blood pressure as well as preventing angiotensin II which stimulates vasoconstriction.
This can be detrimental in a patient with congestive heart failure thus, vasodilator drugs such as ACE inhibitors are useful
Describe the process that stimulates release of ADH hormone
rise in plasma osmolality is detected by the hypothalamus (dehydration, less water in blood)
posterior pituitary gland is then stimulated to release ADH hormone
ADH functions stimulating the opening of aquaporins on the collecting duct
Water moves out of the collecting duct and is then reabsorbed into circulation
Where is ADH synthesised and released from?
posterior pituitary gland
Give examples of renal function tests
glomerular tiltration rate
urea (measure presence in blood)
creatinine (measure presence in blood)
electrolytes Na+, K+
What should the normal glomerular filtration rate be ?
90-120 ml/min /1.73 m2
should be above 60 ml/min at all times
<60 ml/min indicative of kidney disease
<15ml/min indicative of kidney failure
50-70% of kidney function can be lost before urea/creatinine levels are increased. True or false. What is the implication of this?
True
therefore, raised urea is an indication that kidney “failure” has been going for a while
List the major reasons of renal function tests
calculate kidney functions and provide treatment accordingly
denote progress of kidney functions during treatment
aid the situation of hydration
Urinanalysis (urine dip) is used to aid the diagnosis of the following diseases:
UTI
Diabetes
Kidney disease
What information does the urinanalysis provide?
pH
blood
nitrites
WBC
protein (frothy)
glucose
specific gravity
What are the means of performing urinanalysis?
urine microscopy
urine culture
urine cytology
What information can you gather from urine microscopy?
used to detect red blood cells, organisms, cell casts (renal disease), crystals (stone disease)
How do cell casts form ?
cells casts form when myoglobin and other metabolic products of distal tubule and collecting ducts of the nephrons are bound to Tamm-Horsfall mucoprotein.
Tamm-Horsfall mucoprotein + myoglobin/ other DT and CD metabolic products
these casts can be found in the urine