Exam 4 - Renal Flashcards
In to something
Afferent
Out of something
Efferent
PCT
Proximal convoluted tubule
LOH
Loop of Henle
DCT –
Distal convoluted tubule
JGA –
Juxtaglomerular apparatus
Functions of the Kidneys
HELPS TO…
HELPS TO…
1) Regulate blood ionic composition
2) Regulate blood pH
3) Regulate blood volume
4) Regulate blood pressure
5) Maintain blood osmolarity
6) Produce certain hormones
7) Regulate blood glucose levels
8) Excrete wastes and foreign substances
Kidney Functions:
HELPS TO…
Regulate blood ionic composition by?
—Helps to regulate blood levels of ions like sodium (Na+), potassium (K+), calcium (Ca2+), chloride (Cl-), and phosphate (HPO42-)
Kidney Functions:
HELPS TO…
Regulate blood pH by?
—Kidneys excrete variable amount of hydrogen ions (H+) into urine and conserve bicarbonate ions (HCO3-); bicarb is important buffer of H+
Kidney Functions:
HELPS TO…
Regulate blood pressure by?
Kidneys excrete enzyme renin, this activates renin-angiotensin-aldosterone pathway; increased renin = increased blood pressure
Kidney Functions:
HELPS TO…
Excrete wastes and foreign substances by?
By forming urine, kidneys help body to get rid of wastes
- –Ammonia and urea- from deamination of amino acids
- –Bilirubin- catabolism of hemoglobin
- –Creatinine- breakdown of creatine phosphate in muscle fibers
- –Uric acid- catabolism of nucleic acids
Foreign substances
- –From diet
- –Drugs
- –Environmental toxins
Kidney Functions:
HELPS TO…
Maintain blood osmolarity by?
Separately regulates loss of water and loss of solutes in urine, kidneys maintain relatively constant osmolarity close to 300mOsm/liter
Kidney Functions:
HELPS TO…
Produce certain hormones by?
Kidneys produce the hormones calcitriol (active form of Vitamin D) erythropoietin (stimulates production of RBC’s) and renin (hormone/enzyme)
Kidney Functions:
HELPS TO…
Regulate blood glucose levels by?
Like the liver, the kidneys can use amino acid glutamine in gluconeogenesis, which can then release new glucose into the blood stream to help maintain normal level
Right kidney is slightly lower than left – Why?
Liver
Anatomy of Kidneys:
Located in ?
Anatomically between…
Partially protected by the?
retroperitoneal space
…last thoracic and 3rd lumbar vertebrae
11th and 12th ribs
Anatomy of Kidneys:
Concave medial border (Hilum) faces the…
spinal column
Anatomy of Kidneys:
_____ (Hilum) faces the spinal column
Concave medial border
Anatomy of Kidneys:
_____ (Hilum) faces the spinal column
Concave medial border
look at anatomy of kidneys and position of kidneys slides
well done
External Anatomy of the Kidney:
Three External layers?
Renal fascia- Outermost layer
Dense connective tissue anchors kidney to surrounding structure and retroperitoneal wall
Adipose capsule- Middle layer
Fatty tissue surrounding renal capsule, protection and holds kidney in place in cavity (aka “renal fat pad”)
Renal capsule- Innermost layer
Smooth, transparent connective tissue covering that is continuous with ureters; helps maintain shape of kidney and offers protection
External Anatomy of the Kidney:
Dense connective tissue anchors kidney to surrounding structure and retroperitoneal wall
Renal fascia- Outermost layer
External Anatomy of the Kidney:
Fatty tissue surrounding renal capsule, protection and holds kidney in place in cavity (aka “renal fat pad”)
Adipose capsule- Middle layer
External Anatomy of the Kidney:
Smooth, transparent connective tissue covering that is continuous with ureters; helps maintain shape of kidney and offers protection
Renal capsule- Innermost layer
External layers of the kidney, outermost to innermost:
Renal fascia- Outermost layer
Adipose capsule- Middle layer
Renal capsule- Innermost layer
External Anatomy of the kidney, outermost to innermost from PHOTO:
Pararenal fat Renal Fascia Perirenal fat Renal Capsule Kidney
Look at slide 18 on YOUR PPT… this pic is on the exam with a second order question of what does this feature do!
hemisection of kidney with half of photo elements circled
Internal Anatomy of the Kidney:
Cortex
Medulla
Pyramid
Papilla
Columns
Lobe
Minor calyx
Major calyx
Renal Pelvis
Renal sinuses
Renal hilum
Internal Anatomy of the Kidney:
Contains all of the glomeruli and convoluted tubules of nephrons
Also makes the columns that lay between pyramids
Cortex-
Internal Anatomy of the Kidney:
Contains all of the loops of Henle and collecting ducts
Collection of all renal pyramids comprise the medulla
Medulla
Internal Anatomy of the Kidney:
one portion of the medulla
8-18 per kidney
Pyramid
Internal Anatomy of the Kidney:
narrow apex of the pyramid
Contains the papillary duct leading to minor calyx
Papilla
Internal Anatomy of the Kidney:
space between renal pyramids
Is a portion of the renal cortex
Columns-
Internal Anatomy of the Kidney:
- a functional region within the kidney
Pyramid (medulla) + overlying cortex + ½ each adjacent column (cortex)
Lobe
Internal Anatomy of the Kidney:
- small chambers that collect urine directly from papilla
8-18 each kidney
Minor calyx
Internal Anatomy of the Kidney:
- larger chambers that collect urine from multiple minor calyces
2-3 each kidney, extensions of ureters
Major calyx
Internal Anatomy of the Kidney:
- major calyces drain into one large chamber (pelvis),
This mixes/collects all urine from entire kidney
Connects to the ureter outside of the kidney
Renal pelvis
Internal Anatomy of the Kidney:
The kidney is 3-dimensional, so in between the other structures there are spaces that house some adipose tissue, the blood vessels, and nerve supply
Renal sinuses
Internal Anatomy of the Kidney:
- a region
Indentation of kidney where ureter emerges with blood and lymphatic vessels, and nerves
Renal hilum
Renal blood supply:
Renal blood flow is ____ per minute and ___ mL per kidney
Total amount of blood in adult is 4500-5500mL
Starts at ___ level and then branches from there into smaller vessels
Specialized capillary called a _____ is involved in this flow
1200mL; 600mL per kidney
aortic
glomerulus
This glomerulus allows for filtration, but not….
reabsorption
Exits out of glomerulus, no entrance back into it!
Talk through the blood supply of the kidney in order through the entire system…. (16 total)
Aorta Renal artery Segmental artery Interlobar artery Arcuate artery Interlobular artery (also called radial arteries) Afferent arteriole Glomerulus (modified capillary; tufted) Efferent arteriole Peritubular capillaries (both types of nephrons) Vasa recta (juxtamedullary nephrons only) Interlobular vein (also called radial veins) Arcuate Vein Interlobar Vein Renal Vein Inferior vena cavae
Blood flows into the kidney’s to get filtered
-It enters each corpuscle, gets filtered through the glomerulus, and exits the corpuscle to flow into a capillary system
—–Blood is filtered in the _____, where things can be removed only
—–When in the _____, blood will still act like it does in any other capillary in the body – stuff will move in and out of the capillaries depending on pressure
- This capillary action acts as a….
- —-Depending on the body’s needs, it can reabsorb/secrete more water/solutes as needed
glomerulus
peritubular capillaries/vasa recta
….secondary filter
Blood flows into the kidney’s to get filtered
As blood flows through, certain substances are removed from blood and placed into the urinary tubular system…. this is known as ?
This is known as filtrate
Filtrate is first found in the…..
From there is flows through the tubules and then into _____
While in these ducts, things can still be added to it, or removed from it
glomerular capsule (Bowman’s capsule)
collecting ducts
Once the filtrate leaves the collecting duct, it is then called _____
urine
Functional unit of the kidney –approximately 1,000,000 in each kidney
nephron
Nephron consists of two parts:
Renal Corpuscle
Renal Tubule
- where blood is filtered (two parts)
Renal Corpuscle with two parts
1) Glomerulus
2) Glomerular capsule (aka Bowman’s capsule)
- filtered contents (from blood; three parts)
Renal Tubule (three parts as follows):
Proximal Convoluted tubule (PCT)- attached to capsule
Loop of Henle (nephron loop)- middle section
Distal Convoluted tubule (DCT)- distant from capsule, empty into collecting duct
three parts of renal tubule (filtered contents)
PCT
LOH
DCT
Corpuscle and both convoluted tubules reside in ____
cortex
Only Loop of Henle extends into the…
renal medulla
Two Different types of nephrons?
Cortical nephron
Juxtamedullary nephron
– 85% of nephrons
- —-Renal corpuscles lie in outer portion of renal cortex
- —-Short loops of Henle (Just barely reach into outer region of medulla)
- —-Peritubular capillaries only
Cortical nephron
– 15% of nephrons
- —-Renal corpuscles lie deep in the renal cortex
- —-Long loops of Henle (Reach deep into medulla)
- —-Peritubular capillaries that give rise to the Vasa recta (Vasa recta: capillary bed that extends into medulla surrounding the Loop of Henle)
Juxtamedullary nephron
cortical nephrons have ___ capillaries only
peritubular capillaries only
which nephron has short LOH?
Cortical nephron
which nephron has long LOH?
Juxtamedullary nephron
which nephron has Peritubular capillaries that give rise to the Vasa recta ?
Juxtamedullary nephron
capillary bed that extends into medulla surrounding the Loop of Henle
Vasa recta
Cortical nephrons:
Short nephrons
_______ lie in the outermost portion of the cortex
Descending limb of loop of Henle barely dips into the ____
After a hairpin turn, the ascending limb of the Loop of Henle ____
Renal corpuscles
renal medulla
returns to the cortex
Cortical nephrons:
Peritubular capillaries
Arise from the _____
Intermingle throughout the ____
These then flow into _____ and eventually back into systemic circulation
efferent arteriole
proximal and convoluted tubules
interlobular veins
Juxtamedullary Nephrons:
Long nephrons
—Renal corpuscles lie in the cortex
—Descending limb of loop of Henle dives deep into the ___ (which the longer descending loop means what?)
—After a hairpin turn, the ascending limb of the Loop of Henle climbs back to the cortex
renal medulla (Anatomy lends to very dilute and/or concentrated urine)
Juxtamedullary Nephrons:
Peritubular capillaries
Arise from the efferent arteriole
Intermingle throughout the proximal and convoluted tubules
In the juxtamedullary nephrons only, a _____ exists coming off of these peritubular capillaries
specialized capillary system
Juxtamedullary Nephrons:
Vasa Recta
Coming from the peritubular capillaries, this type of capillary system dives deep into the renal medulla
Flows side by side each of the loops of Henle so that things can…..
….Flow out of the capillaries and into the filtrate as well as
Out of the filtrate and into the capillaries
The design with the use of vasa recta is extremely important for keeping a…
constant osmotic (pressure) gradient so that things can flow in and out
short, wide afferent arteriole =
low-resistance input pathway
efferent arteriole plus vasa recta =
high-resistance outflow pathway
flow is controlled by vasoconstriction of which arteriole?
afferent arteriole
The arteriole coming into the corpuscle/glomerulus
Brings blood in for filtration
Wider lumen, thicker walls
Has much more capability to constrict or dilate when compared to efferent arteriole
Afferent arteriole
This arteriole has much more capability to constrict or dilate when compared to the other…
afferent arteriole
Ball of twine-like capillary structure that buds off of the afferent arteriole
Glomerulus
Glomerulus
Modified simple squamous epithelial cells called
podocytes
Podocytes have fingerlike projections _____ that wrap around the glomerular capillaries
(pedicels)
The arteriole leaving the corpuscle/glomerulus
Efferent arteriole
Brings blood with larger solutes (i.e. proteins) into the peritubular capillaries (or vasa recta) and then back into systemic circulation
Efferent arteriole
Smaller lumen size, thinner walls
Smaller lumen size aids in back-pressure sometimes needed for glomerular filtration (continued later in lecture)
Efferent arteriole
PCT/LOH/DCT/Collecting Duct
Together comprise?
Tubule System
A single layer of epithelial cells forms the entire wall of the….
glomerular capsule, renal tubule, and ducts
Each section of cells has minor differences that allow for different functions
Simple cuboidal epithelial cells with prominent microvilli brush-border facing lumen (apical surface)
Microvilli increase surface area for absorption and secretion
PCT- proximal convoluted tubule
(LOH) Loop of Henle (thin descending and thin ascending limb portions)
Histology?
Simple squamous epithelial cells
(LOH) Loop of Henle (thick ascending limb portion)
Histology?
Simple cuboidal to low columnar epithelial cells
DCT- distal convoluted tubule
Histology wise…
Most of DCT – ?
Last part of DCT- ?
Most of DCT – simple cuboidal epithelial cells
Last part of DCT- simple cuboidal epithelial cells that contain
In the DCT…
- receptors for ADH and aldosterone
Principal cells
In the DCT…
- help play a role in blood pH
Intercalated cells
Collecting Duct
Simple cuboidal epithelial cells that also contain:
Principal cells- receptors for ADH and aldosterone
Intercalated cells- help play a role in blood pH
Last part of DCT- simple cuboidal epithelial cells that contain:
Principal cells- receptors for ADH and aldosterone
Intercalated cells- help play a role in blood pH
The fluid that enters the afferent arteriole and into the glomerulus
The fluid that gets “filtered” in the glomerulus
Blood/Serum
The leftover blood/serum and components not filtered into the glomerular capsule, leave the corpuscle via the
efferent arteriole
The fluid/solutes that were filtered out of blood at the glomerulus
The fluid/solutes that enters the renal tubular system at the glomerular capsule
Fluid/solutes can still be reabsorbed/secreted over and over again
Filtrate
Once the filtrate leaves the collecting ducts, it is now called “urine”
Urine
Nephrons and Collecting ducts perform three functions:
1) glomerular filatration
2) tubular reabsorption
3) tubular secretion
water and many solutes found in blood move across the wall of the glomerulus, into the glomerular capsule (Bowman’s capsule) and into tubules
Glomerular filtration:
water and solutes that are now flowing through the tubule system can get reabsorbed (~99% of filtrate is reabsorbed back into bloodstream)
Tubular reabsorption:
due to the peritubular capillaries and vasa recta, there is still the chance to dump unwanted materials into the filtrate such as wastes, drugs, excess ions
Tubular secretion:
once out of the collecting duct, there is no more opportunity for exchange; expelling waste matter
Excretion:
Garbage trucks dump smaller garbage (potential recyclables) into a mechanism that can sort out recyclables
Glomerular filtration
Large items (such as appliances) are left on the truck to be taken elsewhere Proteins/RBC’s that cannot make it through the filtration membrane
Still in blood, exits glomerulus via efferent arteriole
Smaller refuse is placed onto a conveyor belt where workers separate the useful components (cans, plastic, glass)
Reabsorption of useful products (while in tubule system)
The unusable refuse is thrown back into the garbage truck to be sent to the landfill
Wastes are secreted back into the ducts (filtrate) to be made into urine and excreted
The amount that makes it into the glomerular capsule space and tubule system
Glomerular Filtration
Adults create 150-180 liters of filtrate a day
true
99% is usually reabsorbed and returned to circulation
Glomerular Filtration
Glomerular Filtration 99% reabsorbed…. Leaving only…
1-2 liters of urine produced a day
Filtration Membrane
Glomerular capillaries and podocytes form a “leaky” barrier in the capsule
Loosely packed- allows water and certain solutes to pass into capsular space
Prevents most plasma proteins, blood cells, platelets from getting into capsular space
Filtration Membrane
Glomerular ___ and ____ form a “leaky” barrier in the capsule
capillaries and podocytes
Filtration Membrane Consists of three layers of filtration:
Filtration Membrane Consists of three layers of filtration:
1) Fenestrations of endothelial cells (inner most layer of capillary)
- —Prevents blood cells from passing, but allows all other components of blood plasma through
2) Basement membrane/Basal lamina (middle layer of capillary)
- —Prevents large proteins from passing through
3) Slit membranes between pedicels (podocyte arms; outer most layer of capillary)
- —Prevents filtration of most other proteins
Interspersed throughout the glomerular capillaries
Regulate surface area available for filtration
Mesangial Cells and Filtration Membrane
Mesangial Cells and Filtration Membrane:
Regulate surface area available for filtration
When relaxed, _____
When contracted, _______
surface area is maximal
reduced area available
when mesangial cells are relaxed surface area…
is maximal
when mesangial cells are contracted surface area…
reduced area available
Glomerular Filtration Pressure
Although still capillaries, pressure is higher in these than in any other capillaries in the body
Larger surface area
Larger fenestrations for easier filtration
Efferent arteriole is smaller than the afferent
Efferent arteriole is smaller than the afferent
This then requires more pressure to get plasma…
This pressure builds backwards into the glomerulus…
…OUT of the glomerulus through the efferent arteriole
…increasing filter pressure (positive pressure)
Pressure in glomerulus pushing outward into capsular space
Usually 55mmHg
Glomerular blood hydrostatic pressure (GBHP)
Hydrostatic pressure exerted by the fluid in capsular space that pushes inward on the visceral glomerular membrane
“back pressure”
Usually 15mmHg
Capsular hydrostatic pressure (CHP)
Pressure due to proteins in blood plasma (mainly albumin)
Opposes filtration (Pulls on fluid/solutes to keep them in the glomerulus if possible)
Usually 30mmHg
Blood colloid osmotic pressure (BCOP)
Net Filtration Pressure / NFP is the pressure that is supposed to
PROMOTE filtration
NFP = ?
in healthy kidneys about how many mmHg?
NFP= GBHP-CHP-BCOP
NFP= 55mmHg-15mmHg-30mmHg
10mmHg – normal NFP in healthy kidneys
As long as the NFP is a positive number,
filtration will occur
If NFP calculates into a negative number,
NO FILTRATION is occurring