RENAL BLOOD FLOW Flashcards
Urine comes from the____
It enters the kidney → forms the urine, and leaves via the____
blood
ureter
• Arterial supply: renal arteries from the________
The blood enters the kidney and passes through the ______coming from the_____
abdominal aorta
renal artery
abdominal aorta
• Venous return: renal veins drain into the______
The blood that will leave the kidney will leave via the_____, which will go into the_____
inferior vena cava
renal vein
inferior vena cava
Surround PCT and DCT
PERITUBULAR CAPILLARIES
IMMEDIATE reabsorption of essential substances from PCT happens
FINAL adjustment of urinary composition in DCT
Peritubular capillaries
Substances that have to be reabsorbed in these tubules (PCT and DCT) are sent to the______
Facilitates reabsorption through PCT and DCT
peritubular capillaries
Adjacent to the loop of henle
VASA RECTA
• Major exchanges of salt and water between the blood and the medullary interstitium
• Facilitates the reabsorption with the loop of henle
Vasa Recta
RENAL BLOOD FLOW
• In a____ person (_____body surface) → the total renal blood flow is_______
70kg; 1.73m^2
1,200 mL/min
refers to the total blood composition composed of plasma and blood cells
Total renal blood flow
Total renal plasma flow →______
600-700mL/min
More than half of the total renal blood flow is the______
renal plasma
Glomerular filtration rate →_____
Reabsorbed →______
Excreted urine →______
125 mL/min
124 mL/min
1 mL/min
DISTRIBUTION OF BLOOD IN THE KIDNEY
RSIAC AGE PVC AIR
Renal artery
Segmental arteries
Interlobar arteries
Arcuate arteries
Cortical radiate arteries
Afferent arterioles
Glomerulus
Efferent arterioles
Peritubular capillaries
Venules
Cortical radiate veins
Arcuate veins
Interlobar artery
Renal vein
DISTRIBUTION OF BLOOD IN THE KIDNEY
Blood enters the kidney through the_____ → will divide to form the____
→ will further subdivide into
_____→ will further branch out to form the _____→ will further subdivide to form the_____
Then, it will give rise to the____, which is the blood vessel that supplies blood to the glomerulus Inside the glomerulus, the blood will undergo filtration,
If there are components of the blood that are not filtered → sent back to the circulation through the _____→ goes to the _____ and ____→ from there, it will merge to form the_____ → will give rise to the_____ → will form the____ → the interlobar vein will send blood to exit the kidney and join the systemic circulation through the_____
renal artery
segmental artery
interlobar artery
Arcuate artery
interlobular artery
afferent arteriole
efferent arteriole
peritubular capillaries and the vasa recta
interlobular vein
arcuate vein
interlobar vein
renal vein
• the purpose of ______is to facilitate the reabsorption of substances in their respective parts of the nephron
blood vessels
Types of nephron
• Cortical (85%)
• Juxtamedullary (15%)
URINE FORMATION
In order for urine to form, it has to undergo three steps:
Glomerular filtration
Tubular reabsorption
Tubular secretion
• Contains the renal corpuscle (____ and _____) and
the associated renal tubules
glomerulus and Bowman’s capsule
PARTS OF A NEPHRON
- Renal corpuscle
- Proximal tubule
- Loop of henle
- Distal tubule
Proximal Tubule
• Proximal convoluted tubule or_______
• Proximal straight tubule or
______
pars convoluta
pars recta
Distal Tubule (3)
• Thick ascending limb
• Distal convoluted tubule
• Connecting segment or the late distal tubule
Excretion =
Filtration - Reabsorption + Secretion
– composed of a coil of approximately 8 capillary lobes referred to as_____ enclosed within the _____
Glomerulus
capillary tufts
Bowman’s capsule
• Filterability of solutes depend on
their_____ and _____
size and charge
•______ – Nonselective filter of plasma substances
Glomerulus
• Several factors affect the filtration processes (3)
• Structure of the capillary wall
• Hydrostatic and oncotic pressure
• Renin-Angiotensin-Aldosterone System
GLOMERULAR FILTRATION
When blood enters the kidneys through the _______→ undergoes filtration within the______
Substances that are not filtered will be sent to the_______ → systemic circulation
Once the blood is filtered → becomes a_____
This will navigate the renal tubules until it becomes____
afferent arteriole
glomerulus
efferent arteriole
filtrate
urine
GLOMERULAR FILTRATION
• Structure of the capillary wall
• Fenestrated endothelial cells
• Basement membrane
• Epithelial podocytes
• Fenestrated endothelial cells
•______ holes (______or transcellular ‘windows’) that provide no restrictions to______
• Does not allow passage of______
80-100 nm; fenestrae; water and small
solutes
cells and large molecules
• a complex mesh of proteins that restricts intermediate-sized to large solutes (MW >1 kDa)
Basement Membrane
• Basement Membrane: a complex mesh of proteins that restricts
intermediate-sized to large solutes (MW_____)
> 1 kDa
Basement membrane
• 3 layers:
lamina rara interna
lamina densa
lamina rara externa
• Forms the filtration slit/slit diaphragm
Epithelial podocytes
→ returning essential substances from the filrate back to the circulation
Substances to be reabsorbed goes to the peritubular capillaries until they reach the renal vein
Tubular Reabsorption
→ returning essential substances from the filrate back to the circulation
Substances to be reabsorbed goes to the peritubular capillaries until they reach the renal vein
Tubular Reabsorption
Any substance that was not filtered and has to be removed from the body
From the peritubular capillaries → they are sent back to the tubule
TUBULAR SECRETION
4 DIFFERENT PATHWAYS SUBSTANCES NEED TO BE FILTERED FOLLOW THROUGH
• Filtration only
• Filtration andPartial Reabsorption
• Filtration and Complete Reabsorption
• Filtration and Secretion
• Substances that are completely
filtered but not reabsorbed nor
secreted
• One substance that follow this path is ____
Filtration only
creatinine
• Substances that are filtered but undergoes partial reabsorption
______→ only a portion was reabsorbed and the other portion is excreted as part of the urine
Substance that follows this path are_____ and _____
FILTRATION AND PARTIAL
REABSORPTION
Partial reabsorption
sodium and chloride ions
• Substances that are filtered and
undergoes complete reabsorption
• These substances in normal conditions are not present in the urine since these
substances needs to be completely reabsorbed
Substances that follow this path is____
• In cases of diabetes mellitus →
glucose is detected in the urine
FILTRATION AND COMPLETE REABSORPTION
glucose
• Substances are filtered but they are no reabsorbed instead they are secreted
• These substances enter the nephron in two ways: Glomerular filtration and tubular secretion
• Substances that follow this path are_____ and _____
FILTRATION AND SECRETION
organic acids and bases
Filtration only
Creatinine
FILTRATION AND PARTIAL
REABSORPTION
Sodium and chloride
FILTRATION AND COMPLETE
REABSORPTION
Glucose
FILTRATION AND SECRETION
Organic acid and bases
2 blood vessels connected to the glomerulus
Afferent arteriole
Efferent arteriole
• facilitates entry of blood towards the glomerulus
Afferent arteriole
• It is the arteriole
To induce an increase in the blood flow
towards the glomerulus
Afferent arteriole
facilitates exit of blood from the gomerulus
Efferent arteriole
_______→ where the blood components stay In the endothelial cells, the spaces are called_____
Capillary lumen
fenestrae
First line of filtration
FENESTRATED ENDOTHELIAL CELLS
provide no restrictions to water and small solutes
Does not allow passage of cells and large molecules
FENESTRATED ENDOTHELIAL CELLS
Second layer of filtration
GLOMERULAR BASEMENT MEMBRANE
GBM
______
Directly beside the endothelial cells
______
Middle layer of the basement
_______
Layer beside podocytes
lamina rara interna
lamina densa
lamina rara externa
The podocytes have long foot processes called______
→ are closely linked to each other
pedicels
SHIELD OF NEGATIVITY
The______ are richly endowed with fixed negative charges that hinder the passage of plasma proteins which are negatively charged
Only _______substances can pass through
Thus, normally,______ are not seen in the urine because they are repelled by the capillary wall
fenestrations
small and positively charged
proteins
SHIELD OF NEGATIVITY
_________ greatly hinders proteins, partly because of strong negative electrical charges associated with ______
Rich in other proteoglycans such as____ and ____
Basement membrane
heparan sulfate proteoglycans
laminin and agrin
SHIELD OF NEGATIVITY
Podocytes are covered by______ with negative charges
glycoproteins
S H I E L D O F N E G A T I V I T Y
• The_______ are richly endowed with fixed negative charges
that hinder the passage of plasma proteins
•_______ greatly hinders filtration of plasma proteins,
partly because of strong negative electrical charges associated with
heparan sulfate proteoglycans
•______ are covered by glycoproteins with negative charge
fenestrations
Basement membrane
Podocytes
3 pressures
Hydrostatic pressure
Oncotic pressure
Capsular pressure
Glomerular hydrostatic pressure (____)
Bowman’s capsule colloid osmotic pressure (___)
Bowman’s capsule hydrostatic pressure (___)
Glomerular capillary colloid osmotic pressure (___)
60
0
18
32
_____forces water and most solutes in blood plasma across the wall of glomerular capillaries
Fluid is filtered and becomes____
Blood pressure
glomerular filtrate
FORCES IN GLOMERULAR FILTRATION
These pressure are acting inside the renal corpuscle
_________→ are brought about by the presence of proteins in the blood vessel
Colloid osmotic pressure
FORCES FAVOURING FILTRATION (mm Hg)
Glomerular hydrostatic pressure (60)
Bowman’s capsule colloid osmotic pressure (0)
FORCES OPPOSING FILTRATION (mm Hg)
Bowman’s capsule hydrostatic pressure (18)
Glomerular capillary colloid osmotic pressure (32)
Refers to the pressure exerted by the afferent arteriole as it pushes fluid inside the glomerulus
This pressure is much higher than the bowman’s capsule hydrostatic pressure since it carries more fluid
Glomerular hydrostatic pressure (60)
→ since there are no protein inside the bowman’s capsule since it was already repelled back to the efferent arteriole
Bowman’s capsule colloid osmotic pressure (0)
Pressure of the fluid inside the bowmann’s capsule that will attempt to oppose the pressure exerted by the glomerular hydrostatic pressure
Bowman’s capsule hydrostatic pressure (18)
Pressure exerted by the proteins at the glomerular capillary
The proteins that are travelling inside the glomerulus that are waiting for entry will oppose since they are heavy solutes → thus, exerting pressure against the plasma fluid entering the glomerulus
Glomerular capillary colloid osmotic pressure (32)
Net filtration pressure
Formula and solution
• Glomerular hydrostatic pressure – ( Blood colloid osmotic pressure (BCOP) + Capsular hydrostatic pressure (CHP))
• 60 mm Hg – (32 mm Hg + 18 mm Hg)
• 10 mm Hg
Renin angiotensin aldosterone system
JUXTAGLOMERULAR APPARATUS
• Consists of:
•________in afferent arteriole sense the blood pressure (secretes renin)
•_______ in the DCT sense the sodium in the filtrate
Juxtaglomerular cells
Macula densa
JUXTAGLOMERULAR APPARATUS
• Consists of:
• Juxtaglomerular cells in afferent
arteriole sense the_____(secretes renin)
• Macula densa in the DCT sense the____ in the filtrate
blood pressure
sodium
• As a result of the glomerular mechanisms:
• Approximately______ of water-containing low molecular weight substances are filtered every minute
120 mL
• The only difference between the urine filtrate and plasma is the absence of_____
proteins
• Analysis of the fluids as it leaves the glomerulus shows to have specific gravity of_____
1.010
