advanced renal anatomy and physiology body fluids and gross external anatomy internal gross anatomy...
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ADVANCED RENAL ANATOMY AND PHYSIOLOGY
Body Fluids and Gross External AnatomyInternal Gross Anatomy of Kidney
BODY FLUIDS
Water is the major component of the body
Makes up 45-80% of the body weight
DISTRIBUTION OF BODY WATER
Two major compartments• Intracellular (Inside cells)
• 2/3 of total body water
• Extracellular (Outside cells)• 1/3 of total body water
• Intravascular (within a blood vessel)
• 5% of body weight
• Interstitial (water between cells, organs, tissues)
• 15% of body weight
DISTRIBUTION OF BODY WATER
Solvent• Any liquid in which a substance can be
dissolved
Solute• Substance being dissolved
Solution• Stable mixture of two or more substances in a
single phase
DISTRIBUTION OF BODY WATER
Colloid
• State of matter where large molecules are suspended in a liquid
Colloid dispersion
• Substance with components of one or two phases
DISTRIBUTION OF BODY WATER
Movement of water• Water diffuses freely
• Osmotic pressure
Osmotic pressure• Force produced by solvent particles of a solution as
they move through a semi-permeable membrane
• Depends on the number of particles in a solution
• Inversely proportional to the volume of a solvent
• Varies directly with temperature
DISTRIBUTION OF BODY WATER
Osmosis• The movement from high
concentration to low concentration across a membrane
• Equalize concentration on either side
Isotonic 0.9% Hypertonic > 0.9%
• Will draw water out of cells or tissues
http://chsweb.lr.k12.nj.us/mstanley/outlines/DiffosmosAP/
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WHAT IS THISGARBAGE?!!!
OSMOTIC PRESSURE
Typical membranes restrict passage of colloidal particles
Proteins account for plasma’s high colloid osmotic pressure• Albumins
• 60% of plasma proteins
• Most abundant protein for transporting
CONTROL OF WATER MOVEMENT
Regulated by
• Thirst• Low water intake-levels of sodium increase
• Kidneys decrease urine volume
• High sodium-body increases amount of retained water
• Kidneys secrete ADH
• Water excretion by the Kidneys
Water Loss Sensible water loss
• Urine and GI tract• Vomiting, diarrhea, suctioning from stomach
Insensible water loss• Skin (Fever)
• Lungs (Inadequate humidity)• Artificial airways
• Increased ventilation
Tracheostomy patient may lose an additional 700ml/day of water if humidification is inadequate
KIDNEYS
Kidneys are Retroperitoneal
• Lie behind (outside) the lining of the abdominal cavity
http://cache.eb.com/eb/image?id=1398&rendTypeId=4
http://www.owensboro.kctcs.edu/gcaplan/anat2/notes/Image131.gif
KIDNEYS
Maintain the volume and concentration of body fluids by
• Filtration and re-absorption of sodium
• Water secretion regulated by anti-diuretic hormone (ADH)
• Any material that is filtered and not reabsorbed will be lost in urine
FUNCTION OF THE URINARY SYSTEM
Homeostasis of the body
• Controlling volume and concentration of blood
• Removing and restoring select amounts of water and solutes
• Excreting select amounts of wastes
FUNCTION OF THE KIDNEYS
Excrete end products of metabolism
Control concentration of body fluids
FUNCTION OF THE KIDNEYS
Erythropoiesis
• Mechanism to speed up production of RBC’s
• Stimulated by oxygen deficiency in the kidney cells
EXTERNAL ANATOMY
Renal Cortex• Outer region of kidney
Three layers of tissue around kidney
• Renal capsule
• Adipose capsule
• Renal fascia
INTERNAL ANATOMY http://medicalimages.allrefer.com/large/kidney-anatomy.jpg
INTERNAL ANATOMY
Parenchyma
• Area of cortex that includes pyramidsNephron
• Functional unit
RENAL BLOODFLOW
20% of blood pumped by the heart each minute enters the kidneys through the renal artery
SUBSTANCES CLEARED FROM THE BLOOD
Excess ions• Sodium is 90% of the positive ions in extracellular
fluid• Increased sodium=increase extracellular osmotic
pressure
• Decreased sodium-decreased extracellular osmotic pressure
• Kidney controls concentration of sodium by regulating amount of water in the body
• Secretion of ADH and thirst
Anti Diuretic Hormone (ADH)
ADH affects the Reabsorption of water in the distal convoluted tubule and collecting duct
Increased ADH = increased Reabsorption of water
Released by posterior pituitary gland via stimulation from the hypothalamus
SODIUM
Primary positive ion in extracellular fluid• Fluids (blood plasma, i.e. intravascular)
Osmoreceptors in hypothalamus• Responsible for maintaining optimal salt and
water balance in the body
• Sense balance of sodium and water concentration in extracellular fluid
SODIUM
Osmoreceptors in hypothalamus (cont)
• Loss of body water• Hypernatremia
• Excess body water• Hyponatremia
SODIUM
Same system can be used in medical treatment to regulate body fluids• Diuretic drug given
• Kidneys excrete sodium
• Osmoreceptors in blood
• Additionally sense lower sodium concentration in the blood
Hypertension is an early sign of renal failure
POTASSIUM
Normal 3.5-5 mEq/L• Primary intracellular cation
• Important in maintaining fluid and electrolyte balance in body
Muscle contraction and sending nerve impulses• Action potential
POTASSIUM Hypokalemia
• Potentially fatal
• Accompanies diarrhea/vomiting/increased diuresis
• Symptoms include• Muscle weakness
• Paralytic ileus
• ECG abnormalities (Arrhythmia, Cardiac arrest)
• Decreases reflexes
• Respiratory paralysis
• Alkalosis
May need to replace K whenever diuretics are given
POTASSIUM
Increased potassium• Metabolic acidosis
• Direct stimulation of kidney to transport potassium into urine
• Indirect stimulation of adrenal cortex to produce aldosterone
• Kidney cells transport potassium into urine
CALCIUM
Deficit• Affect bone and tooth formation
Too much• Kidney stones
Long term defect• Osteoporosis
Adults need 100-1300 mg calcium daily
RENAL FAILURE
Decrease in glomerular filtration rate• Increased serum creatinine
Chronic renal failure• Develops slowly w/ few symptoms
• Kidney diseases Acute renal failure
• Rapidly progresses
• Characterized by oliguria
NEPHRON
Functional unit of the kidney
Regulates water and soluable substances• Filtering blood
• Reabsorbing what is needed
• Excreting the rest as urine
http://faculty.etsu.edu/currie/images/kidney1.jpg
NEPHRON
Eliminate waste Regulate blood volume and pressure Control levels of electrolytes and metabolites Regulate blood Ph Function regulated by endocrine system
• ADH
• Aldosterone• Hormone that governs Na+ Reabsorption in the kidneys
• Parathyroid hormone
NEPHRON Nephron composed of 2 sections
• Renal corpuscle
• Initial filtering component
•Filters out large solutes
•Delivers water and small solutes to renal tubules
• Renal tubule
•Specializes in reabsorption and secretion
NEPHRON
Controls blood concentration and volume• Removing selected amounts of water and electrolytes
Regulate blood pH• Regulates secretion of H+ and reabsorption of HCO3
-
Remove toxic wastes from blood• Remove materials from the blood
• Return materials the body requires
• Eliminate anything left over
NEPHRON FUNCTION Filtration
• Filters a large portion of plasma through glomerular membrane to nephron tubules
Reabsorption• Movement of substances out of the renal tubules into the blood
capillaries• Fluid flows into tubules
• Unwanted substances pass to urine
• Substances needed by body reabsorbed back into plasma (capillaries)
Secretion• Substances in plasma directly secreted into epithelial cells lining
tubules• Into tubular fluid
***Urine formed by three processes: Filtration ,Reabsorption, secretion
NEPHRON ANATOMY
Kidney composed of approximately 1,000,000 nephrons
Nephron composed of renal tubule and vascular supply• Renal corpuscle
• Cortex of kidney
• Renal tubule• Dips into medulla
RENAL CORPUSCLE
Renal corpuscle contains• Bowman’s capsule
• Glomerulus inside Bowman's capsule
• Site of initial urine formation Glomerular filtrate
• Fluid from the glomerulus to Bowman’s capsule• Composition of fluid almost same as plasma
• No significant amount of protein
• Fluids further processed along the nephron to form urine In the average adult, approximately 125 mL/min
(180 L/day) of fluid is filtered across the glomerulus
PROXIMAL CONVOLUTED TUBULE
Fluid leaves the Bowman’s capsule and flows into the proximal convoluted tubule.
LOOP OF HENLE
Leaves the proximal convoluted tubule and flows into the loop of Henle.
Loop of Henle is part of the nephron and is found in the medulla of the kidney
DISTAL CONVOLUTED TUBULE Cells lining the tubule have numerous mitochondria
• Allows active transport to take place Ion transport regulated by the endocrine system
• Parathyroid hormone• Reabsorbs more calcium• Excretes more phosphate
• Aldosterone• Reabsorbs sodium• Excretes more potassium
COLLECTING DUCTS
Begins in the renal cortex Extends deep into medulla
• Urine passes by medullary interstitium
• hypertonic
Collecting duct will become permeable to water in presence of ADH• Can reabsorb as much as ¾ water by osmosis
*** Collecting duct not considered part of the full nephron
THE JOURNEY CONTINUES
Lower portions of collecting duct permeable to urea
Urine leaves through the renal papilla• Into the renal calyces
• Renal pelvis
• Ureter
• Bladder
• Urethra
Start to Finish
Glomerulus Proximal convoluted tubule Loop of Henle Distal convoluted tubule Collecting tubule Ureter Urinary bladder Urethra
FORCES CONTROLLING FLUID EXCHANGE
Glomerular filtration rate (GFR)• Quantity of glomerular filtrate formed each
minute in all nephrons of both kidneys• Normal is 125 mL/min (180 liters/day)
FORCES CONTROLLING FLUID EXCHANGE
http://blog.lib.umn.edu/trite001/humananatomy/glomerulus.jpg
http://www.gcrweb.com/HeartDSS/charts/fig4.jpg