

MAINTAIN HOMEOSTASIS OF pH,
COMPOSITION AND VOLUME OF BODY
FLUIDS
REMOVES:


METABOLIC WASTE, EXCESS MATERIAL,
FOREIGN SUBSTANCES (DRUGS)





KIDNEYS
URETER S
URINARY BLADDER
URETHRA
FUNCTIONS?
http://miyessence.files.wordpress.com/2006/12/urinary.jpg





LOCATED RETROPERITONEALLY
12TH THORACIC TO 3RD LUMBAR
VERTEBRAE
RENAL SINUS AT HILUM: BLOOD VESSELS,
URETER, NERVES, LYMPHATIC VESSELS
RELEASES ERYTHROPOIETIN ?
RELEASES RENIN ?


BLOOD PRESSURE
ACTIVATES VITAMIN D ?

CALCIUM ABSORPTION
http://depts.washington.edu/ostomy/urostomy/urinary-sys.gif
http://www.biog1105-1106.org/demos/105/unit7/media/human-urinary-system.jpg

RENAL PELVIS



RENAL MEDULLA:



FUNNEL SHAPED SAC AT URETER ORIGIN
WHERE MAJOPR CALYCES MERGE
RENAL PYRAMIDS
MINOR CALYCES TO MAJOR CALYCES
RENAL CORTEX:
OUTER LAYER
 DIPS IN BETWEEN PYRAMIDS = RENAL
COLUMNS
RENAL CAPSULE
FIBROUS CONNECTIVE TISSUE
PROTECTION, MAINTAIN SHAPE




ARTERIES CAN CARRY 30% OF BLOOD TO
KIDNEYS ?
RENAL ARTERY HAS _________________
BLOOD
RENAL VEIN HAS _________________
BLOOD









Descending aorta
Renal artery
Interlobar artery
Arciform arteries
Interlobular arteries
Afferent arterioles
Glomerulus
Efferent arteriole
Capillary net



FUNCTIONAL UNIT OF KIDNEY
1 MILLION PER
PARTS
 RENAL CORPUSCLE
 GLOMERULUS
 GLOMERULAR OR BOWMAN’S CAPSULE
 2 LAYERS OF SQUAMOUS EPITHELIAL
 VISCERAL AND PARIETAL TO TUBULE
 VISCERAL CELLS: PODOCYTES
 HAVE PROCESS AND SECONDARY PROCESSES =
PEDICELS, INTERDIGITATE TO FORM SLIT PORES
 FUNCTION
 AFFERENT AND EFFERENT ARTERIOLES
http://www.jimstanis.com/images/glomerulus.jpg
http://www.life-enhancement.com/images/005glomerulus.jpg
http://www.life-enhancement.com/images/005glomerulus.jpg


PROXIMAL CONVOLUTED TUBULE
NEPHRON LOOP/ LOOP OF HENLE





DESCENDING LIMB
ASCENDING LIMB
DISTAL CONVOLUTED TUBULE
COLLECTING DUCT/ COLLECTING
TUBULE
THROUGH RENAL PAPILAE TO MINOR
CALYX
http://www.dr-aschatterjee.com/renal.html




ASCENDING LIMB PASSES BETWEEN
AFFERENT AND EFFERENT ARTERIOLE
MACULA DENSA = TALL DENSELY
PACKED CELLS OF ASCENDING LOOP
TOUCHING ASCENDING LIMB
JUXTAGLOMERULAR CELLS IN WALL OF
AFFERENT ARTERIOLE (LARGE VASCULAR
SMOOTH MUSCLE CELLS)
REGULATES SECRETION OF RENIN (CHAP
13)
http://www.cf.ac.uk/biosi/staffinfo/jacob/teaching/jga1.gif

CORTICAL




80%
CORPUSCLE IN CORTEX CLOSE TO SURFACE
SHORT NEPHRON LOOPS
JUXTAMEDULLARY




20%
CORPUSCLE CLOSE TO MEDULLA
LONG LOOP
MOST RESPONSIBLE FOR H2O HOMEOSTASIS


AFFERENT ARTERIOLE DIAMETER
LARGER THAN EFFERENT ?
PERITUBULAR CAPILLARY SYSTEM

VASA RECTA AROUND JUXTAMEDULLARY
NEPHRON LOOP: LOW PRESSURE





WASTES, EXCESS WATER, ELECTROLYTES
GLOMERULAR FILTRATION
 FILTERS INTO NEPHRON RATHER THAN INTERSTITIAL
SPACE
 PRODUCES 180 L OF FLUID/DAY SO MOST?
TUBULAR REABSORPTION
 PICKS UP RIGHT AMOUNT OF WATER, ELECTROLYTES,
GLUCOSE
TUBULAR SECRETION
 REMOVES H+, TOXINS FASTER
URINARY SECRETION = GLOMERULAR FILTRATION +
TUBULAR SECRETION – TUBULAR REABSORPTION


MORE PERMEABLE TO SMALL
MOLECULES: FENESTRATED CAPILLARIES
= WATER,GLUCOSE, AMINO ACIDS, UREA,
URIC ACID, CREATINE, CREATININE,
SODIUM, CHLORIDE, POTASSIUM,
CALCIUM, BICARBONATE, PHOSPHATE,
SULFATE
http://www.jci.org/articles/view/23577/files/JCI0423577.f1/medium



HYDROSTATIC PRESSURE CAUSES
FILTRATION
ALSO AFFECTED BY HYDROSTATIC
PRESSURE IN CAPSULE AND OSMOTIC
PRESSURE IN PLASMA ?
NET FILTRATION RATE = GLOMERULAR
CAPILLARY HYDROSTATIC PRESSURE –
CAPSULAR HYDROSTATIC PRESSURE AND
GLOMERULAR CAPILLARY OSMOTIC
PRESSURE

http://www.youtube.com/watch?v=guOqyi5l
UQQ

http://www.natgeoeducationvideo.com/film/
1115/the-urinary-system

http://www.youtube.com/watch?v=tQzqGH
KkdE8&NR=1&feature=endscreen



FILTRATION RATE AFFECTED BY ANYTHING
THAT AFFECTS GLOMERULAR HYDROSTATIC
PRESSURE, GLOMERULAR PLASMA OSMOTIC
PRESSURE, OR CAPSULAR HYDROSTATIC
PRESSURE
GLOMERULAR HYDROSTATIC PRESSURE IS MOST
IMPORTANT: ANY CHANGE IN DIAMETER OF
ARTERIOLES, VASODILATION?
VASOCONSTRICTION?
MORE FLUID IS FILTERED BECAUSE OF HIGHER
HYDROSTATIC PRESSURE SO COLLOIND
OSMOTIC PRESSURE DOESN’T AFFECT
FILTRATION AS MUCH, UNLESS IT IS LOWERED ?



ANY OBSTRUCTION (?) WOULD BACK UP
FLUID RAISING THE HYDROSTATIC
PRESSURE OF CAPSULE AND REDUCING
FILTRATION
FILTERS: 25% CARDIAC OUTPUT; 20% OF
PLASMA = 125 ml/MIN; 180 L/DAY : SO
PLASMA IS FILTERED 60X/DAY = 45G
SURFACE AREA OF GLOMERULAR
CAPILLARIES = 2 sq m = SKIN’S SURFACE



MAINLY AUTOREGULATION
BP/VOLUME DROP STIMULATES
SYMPATHETIC NS = VASOCONSTRICTION
OF AFFERENT ARTERIOLES = ? IF
BP/VOLUME INCREASE = ?
RENIN-ANGIOTENSIN SYSTEM: RENAL
BAROMETERS OF AFFERENT ARTERIOLES
STIMULATE SYMPATHETIC NS TO
STIMULATE JUXTAGLOMERULAR CELLS
SECRETE RENIN




DECREASING LEVELS OF SODIUM,
POTASSIUM, CHLORIDE STIMULATE
MACULA DENSA TO SECRETE RENIN
RENIN STIMULATES ANGIOTENSINOGEN
 ANGIOTENSIN I; ANGIOTENSINCONVERTING ENZYME CAHNGES
ANGIOTENSIN I  ANGIOTENSIN II
ANGIOTENSIN II: MAINTAINS SODIUM
BALANCE, WATER BALANCE, BLOOD
PRESSURE
CONSTRICTS AFFERENT OR EFFERENT
ARTERIOLES, STIMULATES SECRETION OF
ALDOSTERONE FROM ADRENAL CORTEX

ANGIOTENSIN II:




VASOCONSTRICTOR OF AFFERENT AND
EFFERENT ARTERIOLES
STIMULATE PRODUCTIN OF ALDOSTERONE:
(FROM?) CAUSES RETENTION OF SODIUM IN
DISTAL TUBULE: LOSES LESS WATER
STIMULATES RELEASE OF ADH: INCREASES
PERMEABILITY OF DISTAL TUBULE AND
COLLECTING DUCT
ANP: (FROM?) RELEASED WHEN BLOOD
VOLUME INCREASES: SO ?



REABSORPTION: MATERIAL
TRANSPORTED OUT TO INTER STITIAL
FLIUD AND DIFFUSE INTO PERITUBULAR
CAPILLARIES
PASSIVE AND ACTIVE MECHANISMS
CAUSED BY: LOW HYDROSTATIC
PRESSURE OF PERITUBULAR CAPILLARIES,
HIGH PERMEABILITY OF CAPILLARIES,
HIGHER COLLOID OSMOTIC PRESSURE OF
PERITUBULAR CAPILLRIES

MOSTLY IN PROXIMAL TUBULE, HAVE
MICOVILLI (?)

GLUCOSE:
 PROXIMAL: ACTIVE TRANSPORT
 UNLESS RENAL PLASMA THRESHOLD IN
REACHED (DIABETES)

WATER:
 PROXIMAL: OSMOSIS

AMINO ACIDS:
 PROXIMAL: ACTIVE TRANSPORT

SMALL PROTEINS:
 PROXIMAL: ACTIVE TRANSPORT: ENDOCYTOSIS


CREATINE, LACTIC, CITRIC, URIC AND
ASCORBIC ACID:
 ACTIVE TRANSPORT
ACTIVE TRANSPORT REQUIRES CARRIER MOLECULES






WATER: OSMOSIS
TIED IN WITH RETENTION OF SODIUM
SODIUM PUMP IN PROXIMAL SECTION
CHLORIDE, PHOSPHATE AND
BICARBONATE MOVE WITH SODIUM IONS
MOST REABSORPTION IN PROXIMAL
TUBULE (70%)
MOST SODIUM IS RETAINED (97-99%)

EPITHELIAL CELLS OF TUBULES SECRETE
SUBSTANCES

ACTIVE TRANSPORT:
 ORGANIC COMPOUNDS LIKE PENICILLIN,
HISTAMINE


HYDROGEN IONS: WHY?
POTASSIUM: WHEN ALDOSTERONE CAUSES
REABSORPTION OF SODIUM = NEGATIVE
CHARGE AND POTASSIUM IS SECRETED


HORMONES: ANP; ALDOSTERONE; ADH
ADH FROM ?
POSTERIOR PITUITARY
 CAUSES DISTAL CONVOLUTED TUBULE AND
COLLECTING DUCTS TO ADD PROTEINS –
AQUAORINS: WATER CHANNELS: OSMOSIS
BECAUSE OF HYPERTONIC MEDULLA
COUNTERCURRENT EFFECT: ASCENDING LOOP
IMPERMEABLE TO WATER BUT LETS
ELECTROLYTES OUT SO INSIDE IS HYPOTONIC
AND OUTSIDE IS HYPERTONIC





DECENDING LOOP IS PERMEABLE TO
WATER NOT SOLUTES, HYPERTONIC
OUTSIDE SO WATER DIFFUSES OUT:
TUBULAR FLUID IS CONCENTRATED
ASCENDING LOOP REABSORBS MORE
SALT, SALT CONCENTRATION KEEPS
MULTIPLYING: COUNTERCURRENT
MULTIPLIER
MORE THAN 4X SOLUTE
CONCENTRATION THAN PLASMA
SALT DIFFUSES INTO DESCENDING VASA
RECTA BUT DIFFUSES OUT OF
ASCENDING: MAINTAINS SALT GRADIENT
IN MEDULLA
mhhe.com

UREA


AMINO ACID BREAKDOWN FOR
GLUCONEOGENESIS
URIC ACID


METABOLISM OF A AND G
10% EXCRETED/ MOST REABSORBED



VARIES ?
95% ?;UREA, URIC ACID, CREATINE, TRACE
AMINO ACIDS, ELECTROLYTES
DIET & PHYSICAL ACTIVITY



.6-2.5L
50-60 ml/MIN
LESS THAN 30 ml/min = KIDNEY FAILURE




DEFINITION: KIDNEY’S EFFICIENCY AT
REMOVING A SUBSTANCE
TESTED TO SEE IF DISEASE OR DAMAGE
INSULIN CLEARANCE TEST: GFR
CREATININE CLEARANCE TEST: GFR:
KIDNEY FUNCTION: USUALLY ALL
REMOVED FROM BLOOD TO URINE






25 cm
BEHIND PARIETAL PERITONEUM TO URINARY
BLADDER
3 LAYERS:
 MUCOUS COAT: TRANSITIONAL EPITHELIUM
 MUSCULAR COAT: SMOOTH MUSCLE: CIRCULAR
AND LONGITUDINAL LAYERS
 FIBROUS COAT: CONNECTIVE TISSUE
MOVES BY PERISTALSIS: STARTED BY PRESENCE OF
URINE
VALVE AT URINARY BLADDER ?
KIDNEY STONE COULD INCREASE PERISTALSIS OR
SYMPATHETIC NS CONSTRICTS URETER AND KIDNEY
SHUTS DOWN





HOLLOW, BEHIND PARIETAL
PERITONEUM
TRIGONE: OPENINGS TO URETER AND
URETHRA
MUCOUS COAT: TRANSITIONAL
EPITHELIUM
SUBMUCOSA: CONNECTIVE TISSUE WITH
GLAND CELLS
MUSCULAR COAT: SMOOTH MUSCLE:
DETRUSOR MUSCLE: FORMS INTERNAL
URETHRAL SPHINCTER @ NECK
ALWAYS SUSTAINED CONTRACTION
 PARASYMPATHETIC NS: REFLEX FOR
URINATION
SEROUS COAT: PARIETAL PERITONEUM
AT TOP, FIBROUS CONNECTIVE TISSUE
REST





MUCOUS MEMBRANE
LONGITUDINAL SMOOTH MUSCLE FIBERS
URETHRAL GLANDS: MUCOUS GLANDS
MALES: PROSTATIC URETHRA PASSES
THROUGH PROSTATE; MEMBRANOUS
URETHRA EXTERNAL URETHRAL
SPHINCTER; PENILE URETHRA

MICTURITION REFLEX:
 STRETCH RECEPTORS STIMULATED; SIGNAL
MICTURITION REFLEX CENTER: IN SACRAL SPINAL
CORD
 PARASYMPATHETIC NS IMPULSE TO DETRUSOR
MUSCLE TO CONTRACT
 CAN STILL BE CONTROLED: EXTERNAL URETHRAL
SPHINCTER, IMPULSES FROM BRAIN STEM AND
CEREBRAL CORTEX
 EXTERNAL URETHRAL SPHINCTER RELAXES:
IMPULSES FROM HYPOTHALAMUS AND PONS
 DETRUSOR MUSCLE CONTRACTS: MICTURITION
 IMPULSES STOP; DETRUSOR MUSCLE RELAXES,
BLADDER FILLS





KIDNEY CELLS START TO DIE AT 20 BUT
NOT NOTICED TILL AFTER 40; 1/3 LOSS BY
80
GLOMERULI SHUT DOWN: LOSS;
DAMAGE;
GFR DROPS AT 40; 75: 125ml  60ml
RENAL TUBULES THICKEN WITH FATTY
ACIDS; DON’T PROCESS DRUGS AND
ORGANICE MATERIAL AS WELL
BLOOD FLOW DECREASES BY 50% @ 80

SLOWER TO RESPOND FOR HOMEOSTASIS:





ARTERIOLES DON’T DILATE AS QUICK
RELEASE OF RENIN DECREASES
CAN’T ACTIVATE VITAMIN D
URETER, URINARY BLADDER AND
URETHRA AREN’T AS ELASTIC: BLADDER
HOLDS 50% LESS AND RETAINS MORE:
MORE FREQUENT URINATION AND MORE
URGENT
INCONTINENCE: LOSS OF MUSCLE TONE
OF BLADDER