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Terms in this set (138)
location of kidneys
at the rear of the abdominal cavity in the retroperitenem; in the abdominal cavity behind the peritoneum
which kidney is lower?
The kidneys help regulate the bleed level several ions. Which ions are most importantly?
Na, K, Ca2, Cl, and HPO4 (phosphate)
How do the kidneys regulate blood pH?
The kidneys excrete hydrogen into the urine and conserve bicarbwhich are an important buffer of H in the blood
How do the kidneys regulate blood volume?
The kidneys adjust blood volume by conserving or eliminating waterin the urine. An increase in blood volome increases blood pressure, a decrease in blood volume decreases blood pressure
How do the kidneys regulate blood pressure?
The kidneys help regulate blood pressure by secreting the enzyme renin, which activates the renin-angiotensin-aldosterone pathway. Increasedurine causes an increase in blood pressure
How do the kidneys maintain blood osmalarity?
By separately regulating loss of water and loss of solutes in the urine. The kidneys maintain a relatively constant blood osmalarity
What are 2 hormones the kidneys produce?
Calcitrol, the active form of vit D, which helps regulate calcium homeostasis and Erythropoietin which stimulates production of RBC's
How do the kidneys regulate blood glucose levels?
Like the liver, the kidneys can use the amino acid glutamine in glucogenesis, the synthesis of new glucose molecules. They can then release glucose into the blood to help maintain a normal glucose level
How do kidneys excrete wastes and foreign materials?
By forming urine, the kidneys help excrete waste substances that have no useful function in the body. Waste excreted in urine that result from metabolic reactions in the body include ammonia and urea from the deamination of amino acids; bilirubin
What does the concave medial border of each kidney face?
the vertebral column
What is near the center of the concave border of the kidney?
An indentation called the renal hilum or hilus.
What emerges through the hilum?
the ureter, blood vessels, lymphatic vessels, and nerves
What are the 3 layers that surround the kidney?
What is the deep layer of the kidney?
The renal capsule. It is a smooth transparent sheet of dense irregular connective tissue that is continuous with the outer coat of the ureter.
What does the renal capsule serve as?
A barrier against trauma and helps maintain shape of the kidney
What is the middle layer of the kidney?
The adipose capsule. It is a mass of fatty tissue surrounding the renal capsule
What does the adipose capsule protect?
It protects the kidney from trauma and holds it firmly in place in the abdominal cavity
What is the superficiaal layer of the kidney?
The renal fascia. It is another layer of thin dense irregular connective tissues that anchors the kidney to surrounding structures and to the abdominal wall.
What is deep to the peritoneum on the anterior side of the kidneys?
The renal fascia
What are the 2 distinct regions of the frontal section through the kidney?
A light red area called the renal cortex and a deep darker reddish brown inner region called the renal medulla
What is the outer portion of the kidney between the renal capsule and the renal medulla?
The renal cortex
Describe the renal cortex.
It's a smooth textured area that extends from the renal capsule to the bases of the renal pyramids and into the spaces between them. (the inner supporting area of the kidney that fills in around the medulla).
What is the renal cortex divided into?
An outer cortical zone and an inner juxtamedullary zone
What does the renal medulla consists of?
several cone shaped pyramids. The base (wider end) of each pyramid faces the renal cortex, and its apex (the narrow side) which is called a renal papilla points toward the renal hilum.
What are the nephrons in the medulla responsible for?
maintaining the salt and water balance of the blood.
What are the structures responsible for maintaining the salt and water balance of the blood?
The vasa recta
the medullary capillary plexus
the loop of henle
and the collecting tubule
What do the renal cortex and the renal pyramids of the renal medulla constitute?
The parenchyma, which is the functional part of the kidney
What is within the paranchyma?
functional units of the kidney - about 1 million microscopic structures called nephrons.
What is the nephrons chief function?
to regulate the concentration of water and soluble substances like Na filtering the blood, reabsorbing what is needed, and excreting the rest as urine
What does a nephron do?
eliminates wastes from the body, regulates bld volume and bld pressure, controls levels of electrolytes and metabolites, and regulates blood pH
What are nephrons regulated by?
The endocrine system by hormones such as aldosteronem ADH, and parathyroid hormone.
synthesized by hypothalamus and released by the posterior pituitary. a vasopressin
produced by zona glomerulosa of adrenal cortex in adrenal gland. Reabsorbs water and ions
Where do filtered fluids from the nephrons drain?
Into large papillary ducts
Where do the papillary ducts extend?
through the renal papillae of the pyramids
Where do the papillary ducts drain?
into capillary structures called minor and major calyces
How many minor calyces does the kidney contain?
How many major clayx does the kidney contain?
2 or 3
What does the minor calyx do?
receives urine from the papillary ducts of one of the renal papilla and delivers it to the major calyx
What happens once filtrate enters the caycles?
It becomes urine bcz no further reabsorption can occur. The reason no further absorption occurs is bcz the simple epithelium of the nephron and ducts becomes transitional epithelium in the calyces
Where does urine drain from the major calyces?
into a large cavity called the renal pelvis then out through the ureter to the urinary bladder
What are the 2 parts of the nephron?
the renal corpuscle where blood plasma is filtered and a renal tubule which the filtered fluid passes
What are the 2 components of the renal corpuscle?
What is the glomerulis?
a network of capillaries that perform the 1st step of filtering blood.
Where does a glomerulus receive it's blood?
from an afferent arteriole
Where does a glomerulus drain to?
an efferent arterioule, unlike most other capillary beds that drain to a venule
What does resistance of the arterioloes in the glomerulus result in?
high pressure within the glomerulus aiding in the process of ultrafiltration where fluids and soluble materials in the blood are forced out of the capillaries into the Bowmans capsule
What is the glomerulus surrounded by?
the bowmans capsule
What is the Bowman's capsule?
a double walled epithelial cup that surrounds the glomerular capillaries
What is filtered in the Bowmas's capsule?
What happens to the blood after it is filtered in the bowman's capsule?
it passes into the renal tubule
How many sections does the renal tubule have?
proximal convuluted tubule
Loop of Henle
Distal convulted tubule
What is the 1st portion of the renal tubule system of a nephron?
the proximal convuluted tubule
Where does the proximal convuluted tubule lead from?
from the bowmans capsule to the loop of henle
What does the proximal convuluted tubule regulate?
the pH of the filtrate by exchanging hydrogen ions in the interstitium for bicarb ions in the filtrate
What is the proximal convuluted tubule responsible for secreting?
organic acids such as creatine and other bases into the filtrate
What happens to fluid entering the pct?
it is reabsorbed into the peritubular capillaries (tiny blood vessels that travel alongsidenephrons allowing reabsorption and secretion between blood and the inner lumen of the nephron)
How is fluid entering the peritubular capillaries driven?
by Na transport from the lumen into the blood by the Na/K/ATPase transport in the basolateral membrane of theepithelial cells. Na reabsorption is primarily driven by this antiporter. This is the most important transport mechanism of the PCT
What is the portion of the nephron that leads from the PCT to the distal convuluted tubule?
loop of henle
What is the loop of henle's main function?
to create a concentration gradient in the medulla of the kidney
Where does the loop of henle create a high concentration of urine?
deep in the medulla near the collecting duct
Where does the loop of henle extend?
ibto the renal medulla, makes a hair pen turn, and returns to the renal cortex
Where is the distal convuluted tubule located?
between the loop of henle and empties into the collecting duct system
what is the distal convuluted tubule responsible for?
regulation of K, Na, Ca, and Ph
Where in the renal tubules is the primary site for the kidneys hormone based regulation of CA?
distal convuluted tubule
What does the Bowmans capsule consist of?
visceral and parietal layers
What does the visceral layer of the bowmans capsule consist of?
modified simple squamos epithelial cells called podocytes. The many footlike projections of these cells (pedicells) wrap around the single layer of endothelial cells of the glomerular capillaries and forms the inner wall of the capsule
What does the parietal layer of the bowmans capsule consist of?
simple squamos epithelium and forms the outer wall of the capsule
What is an area of closely packed specialized cells lining the wall of the distal tubule at the point of return of the nephron to the vascular pole of its parent glomerulus?
What are the cells of the macula densa sensitive to?
the concentration of NaCl in the distal convuluted tubule
What initiates a signal from the macula densa?
a decrease in NACl
What is the microscopic structure in the kidney which regulates the function of each nephron?
the juxtaglomerular apparatus
Whre is the juxtaglomerular found?
in the renal corpuscle and the returning distal convuluted tubule of the same nephron. This location is critical to its function in regulating renal blood flow and the GFR.
What are the 3 cellular compononents of the juxtaglomerular apparatus?
the macula densa of the distal convuluted tubule
smooth muscle cells of the afferent arteriole
the flow of blood through the kidney
peritubular capillaries and vasa recta
inferior vena cava
Pathway of urine drainage
Proximal convuluted tubule
loop of henle
distal convuluted tubule
Where do cortical nephrons have their loop of henle?
in the renal medulla near near its junction with the renal cortex. They have a shorter loop of henle
Where are the juxtamedullary nephrons located?
deep in the renal medulla. Their renal corpuscle is located near the medulla but still in the cortex. They have a longer loop of henle
What is GFR?
the amount of filtrate formed in all the renal corpuscle of both kidneys each minute
What are the 3 basic processes nephrons and collecting ducts perform to produce urine?
What is the 1st step of urine production?
What happens in glomelular filtration?
water and most solutes in the blood plasma move across the wall of glomerular capillaries where they are filtered and move into the glomerular capsule and then into the renal tubule. It is the fluid that enters the capsular sspace
What happens in tubular reabsorption?
as filtered fluids flow through the renal tubules and through the collecting ducts tubule cells reabsorb 99% of filtered water and many useful solutes. The water and solutesreturn to the blood as it flows through the peritubular capillaries and vasa recta
What happens in tubular secretion?
s filtered fluid flows through the renal tubules and collecting ducts the renal tubule and duct cells secrete other materials such as wastes, drugs, and excess ions into the fluid. tubular secretion removes a cubstance from the blood
What is the daily average volume of glomerular filtrate in adults?
females - 150 L
males - 180 L
What % of glomerular filtration return to the blood and how?
99% via tubular reabsorption so only 1-2 liters is excreted in urine
what is the major stimuli that triggers angiotensin 2?
low blood volume or low blood pressure
What does angiotensin 2 stimulate?
activity of Na/H antiporters in proximal tubule cells
What does angiotensin 2 do?
it increases reabsorption of Na, other solutes, and water which increase blood volume and blood pressure
What is the major stimuli that triggers the release of aldosterone?
an increased angiotensin 2 level and increased levels of K promote release of aldosterone by the adrenal cortex
What does aldosterone enhnce?
activity of Na/K pumps in basolateral membrane and Na channels in apical membrane of principal cells in collecting ducts
What does aldosterone do?
it increases secretion of K and reabsorption of Na and Cl; It also increases reabsorption of water which increases blood volume and blood pressure
What is the major stimuli that triggers ADH?
increased osmalarity of extracellular fluid or decreased blood volume promotes the releaase of ADH from posterior pituitary
What does ADH stimulate?
insertion of water channel proteins (aquaporin-2) into apical membranes of principal cells
What does ADH do?
increases facultative reabsorption of water which decreases osmalarity of body fluids
What is the major stimuli that triggers the release of ANP?
stretching of atria of the heart stimulates ANP
What does ANP suppress and what does it inhibit?
reabsorption of Na and water in proximal tubule and collecting ducts; it inhibits secretion of aldosteone and ADH
What does ANP do?
increases secretion of NA in urine, increases urine output and hus decreases blood volume and pressure
What is the normal volume of urine per day?
What is relaxation of the urethral sphincter in response to increased pressure in the bladder called?
What is the tubules from the kidney to the bladder?
How does urine enter and exit the bladder?
enters via ureters and exits via urethra
What does the urethra connect?
the bladder to the genitals for removal of urine
What is the fluid within the cells?
intracellular fluid. It is about 2/3 body fluid. it is also called cytosol
What is the fluid outside of cells?
What is the fluid that makes up about 80% of extracellular fluid?
interstitial fluid. It occupies the microscopic spaces between tissue cells
what is the fluid that makes up about 20% of extracellular fluid?
plasma. It is the liquid portion of blood
Lymph is extracellular fluid that is grouped with interstitial fluid
What are the 2 barriers that separate interstitial fluid, intracellular fluid, and blood plasma?
The plasma membrane
What does the plasma membrane separate?
ICF from ECF
What do blood vessel walls separate?
blood plasma from the rest of the ECF
When is the body in fluid balance?
when the required amounts of water and solutes are present and are correctly proportioned among the various compartments
What is the largest single component of the body?
water. It makes up 45-75% of total body mass depending on age and gender
Is osmosis a passive process?
What governs the urge to drink?
an area in the hypothalamus known as the thirst center
What happens when ur body is dehydrated?
angiotensin 2 and aldosterone promote urinary reabsorption of Na and Cl conserving the volume of body fluids by reducing urinary loss
How is the Na level in blod controlled?
by aldosterone, ADH,and ANP
What happens when Na is low (below 135; a condition known as hyponatremia)?
ADH release ceases; the laack of adh in turn permits greater excretion of water in urine restoration of the normal Na in ECF
What is the primary means of water movement between fluid compartments. Direction of movement is determined by concentration of solutes ("water follows salt
What are most solutes in the body) - inorganic compounds that dissociate into ions (Ex. NaCl Na+ + Cl-).
What maintains electrolyte balance and fluid balance?
Water is gained by:
1. ingestion - of liquids and moist food
2. metabolic water - product of cellular respiration and product of dehydration synthesis
Water is lost by:
1. excretion of urine.
2. evaporation of perspiration/sweat.
3. exhaled by lungs as water vapor.
4. eliminated in feces.
a state in which excessive body water causes cells to swell
Can be caused by:
-consuming water faster than kidneys can excrete it.
-poor renal function.
-drinking plain water after blood loss, excessive sweating, vomiting or diarrhea.
-can result in convulsions, coma & even death.
Bicarbonate Ions (HCO3-)
-abundant in plasma
a.major component of the plasma acid-base buffering system.
b.formed when CO2 enters the RBC → H2CO3 → H+ & HCO3- (enters plasma as a result of the chloride shift).
Calcium Ion (Ca2+) -
-most abundant ion in the body
a.contributes to the hardness of bones and teeth.
b.important roles in blood clotting, neurotransmitter release, maintenance of muscle tone and excitability of nervous and muscle tissue.
c.levels regulated by calcitonin and parathyroid hormone.
Phosphate Ions (H2PO4-, HPO42-, PO43-
a.HPO42- is a buffer of H+ in body fluid and urine.
b.bonds to lipids to form phospholipids.
c.make up proteins, carbohydrates, nucleic acids (DNA/RNA) and ATP
Magnesium Ions (Mg2+)
a.a cofactor for certain enzymes.
b.essential for normal neuromuscular activity, synaptic transmission & myocardial functioning
pH = measure of the concentration of H+ ions in a solution.
Normal pH of systemic arterial blood is 7.35 - 7.45.
Removal of H+ from body fluids depends on 3 major mechanisms:
1. Buffer system - buffers bind to H+ ions removing them from solution
Important buffer systems include: proteins, carbonic acids - bicarbonate buffers & phosphates.
2. ↑ CO2 in exhalation - reduces the level of carbonic acid in blood (↑pH).
Decreasing the CO2 in exhalation will ↑ levels of carbonic acid (↓pH).
3. Kidney excretion of H+ - renal tubules secretes H+ into the urine and reabsorb
HCO3- so it is not lost in the urine.
a systemic arterial blood pH below 7.35 causes depression of the CNS
a systemic arterial blood pH above 7.45 causes CNS to be easily excited or over-excited.
Chloride Ions (Cl-)
most important extracellular anion
a.important role in chloride shift, which exchanges Cl- and HCO3- between RBCs and plasma to maintain electrical balance of RBC.
b.needed for HCl in stomach (hydrochloric acid).
most abundant cation in intracellular fluid
a.important role in the action potentials in neurons and muscle fibers.
b.regulates ICF and pH of all body fluids.
Sodium Ions (Na+)
most important extracellular ion
a.important role in fluid and electrolyte balance (creates most of the osmotic pressure of the ECF).
b.necessary for action potentials in neurons and muscle fibers
ECF - ↑ Na+ & ↑ Cl- (sodium chloride).
ICF - ↑ K+ & ↑HPO42- (potassium & hydrogen phosphates).
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