L16 (renal) Flashcards
what are the components of the urinary system
the kidney x2
ureter x2
bladder
urethra
what glands sits on top of the kidneys
the adrenal gland
what kind of structure are the kidneys
paired organs
how much do the kidneys weigh
150g each therefore they make up 0.5% of our body weight
what % of blood flow do the kidneys receive
25%
what are the functions of the kidneys (6 functions)
water homeostasis (main function)
Regulation of water and ion balance, body pH
Excretion of metabolic wastes
Excretion of foreign chemicals
Endocrine functions - calcitriol, erythropoietin (EPO), renin
Gluconeogenesis
how does the kidney achieve water homeostasis
This is achieved by filtering the blood and controlling what
substances and how much of these substances, along
with water are excreted from the body
what do the Endocrine functions of the kidney do
- calcitriol,
- erythropoietin (EPO),
- renin
calcitriol = Metabolite of vitamin D, It is important for reptake of Ca
erythropoietin (EPO) = Stimulate formation of red blood cells from bone marrow
renin = cleaves angiotensinogen to angiotensin 1
how many L of plasma do the kidneys filter per day
180L
an adult human has 5L of blood. how much of this is plasma
3L
if we have 3L of plasma and the kidneys filter 180L of plasma per day. how many times does the plasma get filtered per day
60x
what % of the filtrate is reabsorbed and what % becomes urine
99% reabsorbed
1% urine
what are the major anatomical features of the kidneys
capsule
cortex - bit between capsule and pyramid
medulla - inbetween the pyramids
pyramid
nephron
minor calyx
major calyx
pelvis (when it leaves the kidney it becomes the ureter)
what supplies blood to the kidneys
the renal arteries
describe the structures that the renal arteries divide into
Renal artery branches until it forms the glomerular capillaries (afferent and efferent arterioles)
then it branches into the peritubular capillaries and then into the vasa recta which surround the nephron
which blood vessels surround the nephron
vasa recta
what takes the blood away from the kidneys
renal veins
which of the following is true
A. The kidney filters about 200 litres of plasma per
day.
B. The kidneys do not produce hormones.
C. The Urinary system has three ureters.
D. The kidneys excrete foreign chemicals
A should be 180L
B incorrect
C = 2 uresters
D is correct therefore D is the answer
what is the smallest functional unit of the kidney
the nephron
how many nephrons do we have in each kidney
how do these numbers decline
1.2 million but this number declines by 50% by the time we reach 60 years of age
whata re the 2 types of nephrons
Superficial (Cortical)
nephrons (entire nephron in the cortex)
Juxtamedullary
nephrons (has a cortical region and a medullary region)
what are the components of the nephron
Glomerulus
Bowman’s
capsule
Proximal tubule
Loop of Henle
Distal tubule
Collecting duct
describe the vascular arrangement around the nephron
renal artery –> afferent arteriole –> glomerular capillaries (in bowman’s capsule) –> efferent arteriole –> peritubular capillaries –> vasa recta
what are the 3 processes of the nephron (in order)
glomerular filtration
tubular secretion
tubular reabsorption
what 3 processes can be ultered to change fluid loss/reabsorption
glomerular filtration
tubular secretion
tubular reabsorption
which of these is false
A. The Nephron is the smallest functional unit of the kidney.
B. The afferent arteriole branches to make the
glomerulus.
C. Each kidney contains more that 1 million nephrons.
D. Reabsorption of material is from the blood to the lumen of the nephron.
D because it should say….
secretion of material is from the blood to the lumen of the nephron to be correct
what is another name for glomerular filtration
ultrafiltration
what is glomerular filtration (ultrafiltration)
Bulk flow of protein-free plasma into the Bowman’s space to form filtrate
what does filtrate contain
The filtrate contains everything in plasma except RBC and proteins
what is the first sign that you might have something wrong with the kidneys
Blood in the urine is the first sign that you have something wrong with your kidneys
what structures make up the renal corpuscle
Glomerulus (capillaries) and bowman’s capsule
describe the Glomerulus (capillaries)
Endothelium (capillary tuft) fenestrated with basement
membrane
can be described as a sieve action
what is bowman’s capsule
it is the outer epithelium that covers the Glomerulus (capillaries)
what does the bowman’s capsule contain
podocytes = inner epithelium
Pedicles = foot like processes
endothelium (of capillaries)
basement membrane
how many solutes are freely filtered
<10,000 MW
what is the Juxtermedualrs apperattis formed by
formed by the macula densa cells of the thick ascending limb
what is the function of the Juxtermedualrs apperattis
its main function is to regulate blood pressure and the filtration rate of the glomerulus.
what forms the filtration barrier
the endothelial cells of the glomerular
capillaries, the basement membrane and the podocytes
what is the role of the fenestrated endothelium
Freely permeable to water, ions, and small solutes but
not cells
what is the role of the basement membrane (for filtration barrier)
its matrix of negatively charged proteins therefore it acts as a charged-based filtration barrier to proteins
what is the role of the podocytes
this is specialised epithelial cells of Bowman’s capsule
Gaps between foot processes (pedicels) form filtration barrier which prevents filtration of proteins and large macromolecules
what is the role of pedicels
to increase the surface area of the filtration barrier
what did Jonah Lomu die of
Nephrotic syndrome
what is Nephrotic syndrome (Jonah Lomu)
Increased permeability of filtration barrier to proteins (mutation in the structure)
Increase in proteins excreted in urine (proteinuria, not normal!)
Inability to concentrate urine, low plasma proteins can lead to edema
which of the following is false
A. The renal corpusle contains the glomerulus and the Bowman’s capsule.
B. Podocytes do not aid with filtration.
C. The basement membrane is negatively charged
to assist filtration.
D. Jonah Lomu died from nephrotic syndrome.
B
what are the glomerular ultrafiltration pressures
Ultrafiltration at the glomerulus is similar to
ultrafiltration seen across tissue capillaries
Hydrostatic pressures (forces) - Blood pressure, this has a big effect on filtration
Oncotic (~osmotic) pressures (forces)
- These are the things that are found in the blood
what pressure favors filtration
Glomerular capillary hydrostatic pressure (PGC) (Blood pressure)
what pressures oppose filtration
Hydrostatic pressure – Bowman’s space (PBS)
- as you move more fluid into this space then you increase the hydrostatic pressure
Oncotic pressure* due to proteins in the glomerular capillary (π GC)
Osmotic pressure in bowman’s capsules should always be……
0mmHg
because if it was more then there would be proteins in in
