Pathophysiology Exam #4 Flashcards
What are the ten functions of the Renal System?
REVIEW OF KIDNEY FUNCTIONS
• EXCRETE END PRODUCTS OF METABOLISM FROM THE BLOOD, such as urea, creatinine, metabolic acids, others
• In coordination with antidiuretic hormone (ADH), REGULATE VASCULAR, INTERSTITIAL, AND INTRACELLULAR OSMOLALITY
AND VOLUME by regulating urine volume and osmolality
• REGULATE ELECTROLYTE AND OTHER SOLUTE BALANCE of body fluids
• REGULATE ACID-BASE BALANCE OF BODY FLUIDS, in conjunction with body buffers in the lungs
• REGULATE BLOOD PRESSURE by controlling vascular volume and by secreting renin, which causes synthesis of
angiotensin II (potent vasoconstrictor) and aldosterone secretion and the lungs
• REGULATE BONE MARROW PRODUCTION OF RBCS BY secreting erythropoietin (from the peritubular endothelial
cells) in response to hypoxia
• SYNTHESIZE VITAMIN D TO it’s most active form, 1,25-DHCC, which helps regulate calcium and phosphate
balance and bone formation
• SYNTHESIZE VARIOUS HORMONES that help regulate renal blood flow, such as PGs (prostaglandins, which is a
vasodilator), endothelin (vasoconstrictor), and nitric oxide (vasodilator)
• PERFORM GLUCONEOGENESIS (only the liver performs more than the kidneys)
o Gluconeogenesis is the production of glucose from non-carbohydrates such as, amino acids
• EXCRETE DRUGS AND TOXINS from the body fluids
What is the anatomic location and size of the Kidneys, and what organ sits on top of them?
• The kidney location is in the retroperitoneal (behind the peritoneal cavity), underneath ribcage (protected by
the ribcage)
• The kidneys should be about the same size; the average adult kidney size is 11 – 13 cm (longitudinally)
• There should be NO MORE THAN A 1.5 cm difference or greater difference between the kidneys
• If there is a ≥1.5 cm difference between the two kidneys; one is to large or one is to small (you need to investigate why)
• Adrenal gland sits on top of the kidneys; they have their own blood flow (BF), autonomic innervation, and lymphatic circulation
o The adrenal glands are actually completely separate organs from the kidneys
* If the patient has a nephrectomy, its very important that the surgeon dissects and removes just the kidney
and not the adrenal gland that is sitting on top of the kidneys*
Describe the blood flow to and from the kidneys and the indications related to them.
• Blood flow:
o You can see the abdominal aorta; and the abdominal aorta is where the renal arteries divide and branch off to provide BF to the kidneys
o So as soon as the LV ejects blood, there is not to far of a distance before the kidneys are perfused
o The kidneys receive 20 – 25% of CO/ minute
o Based on size, the kidneys (that are about the size of your fist) receive a lot of BF and are very vascular
structures
o You also see the renal veins coming off the kidneys and emptying into the inferior vena cava (IVC)
§ It is just as important to have unobstructed out-flow of blood as it is to have unobstructed in-flow of
blood (from the renal arteries)
§ If you have a tumor that obstructs the inferior vena cava and the renal veins, that increases the
pressure within the kidney; when the pressure within the kidney increases, that decreases that amount of BF to that kidney
o Another mechanism that helps propel urine from the kidneys to the bladder is?
gravity
Describe the urinary bladder.
• Urinary bladder
o Smooth muscle pouch
o As urine fills up the urinary bladder, it causes a reflex dilation; so the pressure does not rise in the urinary bladder in direct relation with the volume
o At some point the volume is going to cause such a pressure that it sends afferent impulses to your brain
that says you need to urinate
o Then you have the parasympathetic nervous system which contracts the bladder and relaxes the internal
sphincter
o The external sphincter is (hopefully/ usually) in voluntary control
• The R kidney does sit a little ___ than the L kidney (because of the liver)
lower
CARDIOVASCULAR – KIDNEY INTERRELATIONSHIPS • Renal fraction: \_\_\_\_\_ of CO perfuses kidneys each minute • With average CO: Renal blood flow – \_\_\_\_\_ ml/min. • Altered RBF = altered renal function
- 20 - 25%
* 1000 - 1200 ml/min
The kidneys are enclosed in this thick fibrous
tissue called the _____ _____.
RENAL CAPSULE
What is the function of the renal capsule?
o Helps enclose and protects the kidney
o If the kidney bleeds (like from a percutaneous renal biopsy), that renal capsule will hold that blood in; that can
be very detrimental to the kidney because that blood increases and puts pressure on the tissue (of that kidney) that will ultimately lead to ischemia
Kidneys are divided into the ___ and
___.
cortex and medulla
Renal artery branches off of the ___ ___.
abdominal aorta
The renal artery branches into what other arteries?
segmental arteries (superior, middle, and inferior)
o Superior provides BF to the superior
aspect of the kidney; middle to middle;
inferior to inferior
The renal vein delivers ___ blood back to the IVC.
deoxygenated
If you look at the renal pyramid here (urine is formed) you see these little dots in the membrane called the ___ ___.
• Urine empties thru the papilla into a ___ ___; and the minor calyces empty into their own ___ ___.
- Renal Papill
- Minor Calyx
- Major Calyx
o That urine is then transported in thru the ureter down to the urinary bladder
Trace blood flow from the left ventricle through the kidneys and then back to the mitral valve.
FROM THE LV BACK TO THE RA ** YOU WILL SEE THIS AGAIN **
LEFT VENTRICLE ->AORTIC VALVE -> ASCENDING AORTA -> ARCH OF THE AORTA ->DESCENDING THORACIC AORTA (PIERCES THE DIAPHRAGM) ->ABDOMINAL AORTA->BRANCHES INTO THE L & R RENAL ARTERIES ->SEGMENTAL ARTERIES (SUP, MID, INF) ->INTERLOBAR ARTERIES -> ARCUATE ARTERIES -> INTERLOBULAR ARTERIES -> AFFERENT ARTERIOLES -> GLOMERULUS -> EFFERENT ARTERIOLES -> PERITUBULAR CAPILLARIES ->VASA RECTA -> INTERLOBULAR VEINS -> ARCUATE VEINS -> INTERLOBAR VEINS ->RENAL VEIN -> INFERIOR VENA CAVA -> RIGHT ATRIUM -> TRICUSPID VALVE ->RIGHT VENTRICLE -> PULMONIC VALVE -> PULMONARY ARTERIES -> PULMONARY CIRCULATION -> PULMONARY VEINS -> LEFT ATRIUM -> MITRAL VALVE
What is the blood flow specifically through the kidneys?
1ST RENAL A. 2ND SEGMENTAL A. 3RD INTERLOBAR A. 4TH ARCUATE A. 5TH INTERLOBULAR A. 6TH AFFERENT ARTERIOLES 7TH GLOMERULUS 8TH EFFERENT ARTERIOLES 9TH PERITUBULAR CAPILLARIES 10TH VASA RECTA 11TH INTERLOBULAR V. 12TH ARCUATE V. 13TH INTERLOBAR V. 14TH RENAL V.
What is the functional unit of the kidneys?
Nephron
• Starting at the BOWMANS CAPSULE (completely surrounds those glomerular capillaries)
• The Bowman’s capsule then becomes the ___ ___.
o First you have the ___ proximal tubule
o Convoluted proximal tubule then becomes the ___ proximal tubule
• It then thins out and becomes the ___ ___ ___ ___ ___
o AKA the ______?
• The loop of Henle makes a hairpin turn; this is the ___ ___ ___ ___ ___.
o AKA the _________?
- PROXIMAL TUBULE
- CONVOLUTED
- STRAIGHT
- THIN DESCENDING LOOP OF HENLE
- concentrated segment
- THIN ASCENDING LOOP OF HENLE
- passive diluting segment
• The lumen of the tube then gets larger; this is the _____ _____ _____ _____.
o AKA the ____________?
• Then the ___ ___
o not really discussed much because the ___ distal tubule is very similar in function and structure to
the thick ascending limb of the loop of Henle
o and the ___ distal tubule is very similar in function and structure to the ___ ___ ___.
- THICK ASCENDING LIMB OF THE LOOP OF HENLE
- active diluting segment
- DISTAL TUBULE
- EARLY
- LATE
- CORTICAL COLLECTING TUBULE
AFTER THE DISTAL TUBULE WE HAVE THE ___ ___ ___?
• What is the result once the tubular filtrate leaves the medullary collecting duct?
- MEDULLARY COLLECTING DUCT
* urine
• In the adult, the kidney has how many nephrons?
- 1 – 1.25 million nephrons (2 – 2.5 million if you have both kidneys)
The kidney is divided into a ___ and the ___
cortex and medulla
There are two types of nephrons, what are they?
There are two types of nephrons
o CORTICAL nephrons (on the R side)
o JUXTAMEDULLARY nephrons (on the L side)
What is the characteristics of Cortical nephrons?
§ They are called the cortical nephrons because the
majority of the components of that nephron are located within the cortex of the kidney
§ 85% of nephrons are cortical
What is the characteristics of Juxtamedullary nephrons?
§ These nephrons (as you notice) have long thin
loops of Henle that dive deep deep down into the
medulla
§ Account for the other 15% of our nephrons
§ Responsible for determining the final urine
volume and concentration
Vasa recta lie right next to those long thin ___ ___ ___.
- loops of Henle
The glomerulus contains how many capillaries?
The glomerulus is ~ 12 – 24 capillaries
The Bowman’s capsule is the beginning of the___ ___ ___; it completely surrounds the glomerular
capillaries
-lumen of the tubule
The distal tubule (on each nephron) lies right in between the ___ ___ ___.
o The distal tubule actually comes into contact with the ___ arteriole
- afferent and efferent arterioles
- afferent
There are two different types of specialized cells that are collectively referred to as the ___ ___.
JUXTAGLOMERULAR APPARATUS
• The first group of cells are in the distal tubule itself
and they are called the ___ ____.
• The cells that surround the afferent arteriole are called
juxtaglomerular cells; those are the cells that secrete ___.
- MACULA DENSA
- RENIN
• Now lets look at the different layers of tissues that the tubular filtrate has to traverse to get from the glomerular
capillaries into the lumen of the tubule
o Because that’s out goal…………………………..?
-we want to filter the plasma from the glomerular
capillaries into the lumen of the tubules so that the kidneys can perform their function
The lumen of the glomerular capillaries has blood in it and it has three layers which are?
• This is the lumen of the capillary; it has blood in it • There are three layers: O CAPILLARY ENDOTHELIUM* O BASEMENT MEMBRANE* O PODOCYTE CELL PROCESSES* * These are the three layers that you have to get through to move filtrate from the glomerulus, into the Bowman’s capsule, and into the tubular filtrate
What is the significance of the opening that are located in the Capillary Endothelium of the glomerular capillaries? They are called? They allow what through and prevent what substances from passing through?
• Lets start with the first layer; the CAPILLARY ENDOTHELIUM
o They have these openings of a certain size and they’re actually larger than the openings in normal capillaries (that’s why they’re not called pores)
§ They’re called FENESTRAE (larger than normal openings)
§ Under normal conditions, RBCs, WBCs, platelets should not get through fenestrae in the capillary endothelium
§ Albumin SHOULD be able to get thru
What is the significance of the opening that are located in the BASEMENT MEMBRANE of the glomerular capillaries? They are called? They allow what through and prevent what substances from passing through?
o The next layer is the BASEMENT MEMBRANE; it has openings of a certain size that allows certain substances to either filter or not to filter through
§ Also a selectively permeable membrane
§ Don’t allow (RBCs, WBCs, or platelets) to get thru
§ Albumin should get thru
§ However, the basement membrane is strongly lined with negative charges
§ Albumin is a negatively charged protein
In regards to the basement membrane, what prevents albumin from passing through?
§ Albumin is a negatively charged protein
Q. What do like charges do to each other? They repel each other.
§ It’s the neg charge on the basement membrane that prevents albumin from being filtered from the
glomerulus into the Bowman’s capsule and then into the tubule
§ Based on size, albumin should be able to filter; it’s the negative charges on the basement membrane
that repel the negatively charged albumin
o The final layer of the Glomerular capillaries is the ___ ___.
§ They have these little foot processes that are called ___ ___.
o The final layer is the PODOCYTE CELL PROCESSES
§ They have these little foot processes that are called FILTRATION SLITS
v Filtration slits are of a certain size that allows some substances to pass and some not to pass
§ This is yet another layer that has to be traversed to get form the glomerulus to the Bowman’s capsule
Trace the flow of solute from the Glomerular capillaries to the proximal tubules.
CAPILLARY ->CAPILLARY MEMBRANE (FENESTRAE) -> BASEMENT MEMBRANE ->PODOCYTE CELL PROCESSES (FILTRATION SLITS) -> BOWMAN’S CAPSULE -> PROXIMAL TUBULE
WHAT ARE THE DETERMINANTS OF NET GLOMERULAR FILTRATION PRESSURE AND GFR?
DETERMINANTS OF NET GLOMERULAR FILTRATION PRESSURE AND GFR:
-GLOMERULAR CAPILLARY HYDROSTATIC PRESSURE =
FAVORS FILTRATION
-BLOOD COLLOID OSMOTIC PRESSURE =OPPOSES FILTRATION
-BOWMAN’S CAPSULE HYDROSTATIC PRESSURE = OPPOSES FILTRATION
What is the characteristics of Glomerular Capillary Pressure?
• The first pressure is the GLOMERULAR
CAPILLARY PRESSURE (GCP) or
GLOMERULAR CAPILLARY HYDROSTATIC
PRESSURE (GCP)
o GCHP is based on the amount of BF into the
glomerulus; increase in BF/ blood volume is going to increase the pressure against the walls of the glomerulus and increase capillary hydrostatic pressure
o That FAVORS filtration from the glomerulus into Bowman’s capsule
What is the characteristics of Blood Colloid Osmotic Pressure?
• Then we have the BLOOD COLLOID OSMOTIC PRESSURE (BCOP); which is created by the proteins in the blood, such as albumin
o That OPPOSES filtration from the glomerulus into Bowman’s capsule
What is the characteristics of Bowman’s Capsule Hydrostatic Pressure?
• Finally we have BOWMAN’S CAPSULE HYDROSTATIC
PRESSURE or CAPSULE PRESSURE (CP)
o Fluid and solutes are being filtered from the glomerulus into Bowman’s capsule; so there is fluid in there and that causes pressure and that opposes filtration from the glomerulus into Bowman’s capsule
