The Urinary System Part 2 Flashcards
how can FILTRATE BE REABSORBED?
- reabsorbed by both ACTIVE & PASSIVE PROCESSES
- especially WATER, GLUCOSE, AMINO ACIDS, and IONS
- SECRETION:
- helps to MANAGE pH & RIDS THE BODY OF TOXIC & FOREIGN SUBSTANCES
describe PARACELLULAR REABSORPTION
- passive fluid leakage between cells
- transport between TUBULE CELLS
- leaky within PROXIMAL NEPHRON
- the PRINCIPAL LOCATION of TRANSPORT for H20, Ca, Mag, K, some Na (PCT)
describe TRANSCELLULAR REABSORPTION
- directly through the tubule cells
- going through APICAL MEMBRANE
- enters through CYTOSOL—exiting BASOLATERAL SIDE»_space;> enters the BLOOD
describe TUBULAR REABSORPTION of SODIUM
- SODIUM TRANSPORT across the BASOLATERAL MEMBRANE:
-
Na+ - most ABUNDANT CATION in FILTRATE
- TRANSPORT across BASOLATERAL MEMBRANE
- PRIMARY ACTIVE TRANSPORT:
- out of tubule cell by NA+-K+ ATPase PUMP»_space;> (BULK FLOW) PERITUBULAR CAPILLARIES
- PRIMARY ACTIVE TRANSPORT:
- TRANSPORT across BASOLATERAL MEMBRANE
-
Na+ - most ABUNDANT CATION in FILTRATE
how does TRANSPORT OCCUR across the APICAL MEMBRANE
- NA+ enters TUBULE CELL at APICAL SURFACE:
- SECONDARY ACTIVE TRANSPORT (COTRANSPORT) via FACILITATED DIFFUSION through CHANNELS
describe the ACTIVE PUMPING of NA+ (across the BASOLATERAL MEMBRANE)
- results in strong ELECTROCHEMICAL GRADIENT within TUBULE CELLS
- results in LOW INTRACELLULAR NA+ LEVELS that facilitates NA+ DIFFUSION
- have a LEAKAGE OF POTASSIUM—leaves a NEGATIVE CHARGE
describe SODIUM REABSORPTION
through PRIMARY ACTIVE TRANSPORT provides ENERGY and means for REABSORBING almost every other substance
how are ORGANIC NUTRIENTS REABSORBED?
- organic nutrients reabsorbed by SECONDARY ACTIVE TRANSPORT are COTRANSPORTED with NA+
- have a specific APICAL CARRIER; moves SODIUM DOWN ITS CONCENTRATION GRADIENT
how is WATER REABSORBED?
- reabsorbed by OSMOSIS
- aided by WATER-FILLED PORES called AQUAPORINS
describe OBLIGATORY AND FACULATIVE WATER REABSORPTION
- OBLIGATORY WATER REABSORPTION:
- AQUAPORINS are always present in PCT
- FACULTATIVE WATER REABSORPTION:
- AQUAPORINS are inserted in collecting ducts only if ADH is present
what is the TRANSPORT MAXIMUM
- exists for almost EVERY REABSORBED SUBSTANCE
- reflects NUMBER OF CARRIERS in RENAL TUBULES that are AVAILABLE
- when carriers for a SOLUTE are SATURATED
- excess is excreted in URINE
where is the site of the MOST REABSORPTION?
the PCT;
- exists for almost EVERY REABSORBED SUBSTANCE
- reflects NUMBER OF CARRIERS in RENAL TUBULES that are AVAILABLE
- when carriers for a SOLUTE are SATURATED
- excess is excreted in URINE
describe the NEPHRON LOOP–and its LIMBS OF REABSORPTION
- NEPHRON LOOP:
- DESCENDING LIMB: H20 can leave, solutes cannot
- ASCENDING LIMB: H20 cannot leave, solutes can
how is REABSORPTION in the DCT and COLLECTING DUCT, and what are the FOUR HORMONES that affect its REABSORPTION?
is controlled by HORMONES
- ANTIDIURETIC HORMONE (ADH):
- water — causes the PRINCIPAL CELLS to OPEN AQUAPORINS; increase WATER REABSORPTION
- posterior pituitary
- ALDOSTERONE
- (NA+ REABSORPTION)—leads to INCREASE BP
- affects the DCT and COLLECTING DUCT
- ATRIAL NATRIURETIC PEPTIDE (ANP):
- NA+ is REDUCED—results in DECREASE in BV and BP
- PTH:
- Ca2+—acts on the DCT; increases CALCIUM REABSORPTION
describe TUBULAR SECRETION
- is REABSORPTION IN REVERSE
- occurs ALMOST COMPLETELY in PCT
- selected substances are moved from PERITUBULAR CAPILLARIES through TUBULE CELLS out into FILTRATE
- elimination of UNDESIRABLE SUBSTANCES—passively reabsorbed
describe the COUNTERCURRENT MULTIPLER
- interaction of FILTRATE FLOW in ASCENDING/DESCENDING LIMBS of NEPHRON LOOPS of JUXTAMEDULLARY NEPHRONS
- creates the GRADIENT
describe the COUNTERCURRENT EXCHANGER
- blood flow in ASCENDING/DESCENDING LIMBS of VASA RECTA
- PRESERVES the GRADIENT
- preserved MEDULLARY GRADIENT by;
- PREVENTING RAPID REMOVAL of SALT FROM INTERSTITIAL SPACE
- REMOVING REABSORBED WATER
what is the relationship between the COUNTERCURRENT MULIPLER and EXCHANGER?
both work in UNISON — allows to VARY URINE CONCENTRATIONS
- always have a CONSTANT DIFFERENCE of 200 MOSM
function of the VASA RECTA
- VASA RECTA:
- preserves MEDULLARY GRADIENT
- prevents RAPID REMOVAL of SALT FROM INTERSTITIAL SPACE
- removes REABSORBED WATER
describe the formation of DILUTION
- FORMATION OF DILUTION:
- established MEDULLARY OSMOTIC GRADIENT can now be USED to FORM DILUTE or CONCENTRATED URINE
- OVERHYDRATION:
- produces a LARGE VOLUME OF DILUTE URINE
- DEHYDRATION:
- produces a SMALL VOLUME OF CONCENTRATED URINE
function of a URINALYSIS
-
URINE is EXAMINED for signs of disease
- can be used to test for ILLEGAL SUBSTANCES
- assessment for RENAL FUNCTION that requires BOTH BLOOD and URINE EXAMINATION
- ex. RENAL FUNCTION—can be assessed by MEASURING NITROGENOUS WASTES in BLOOD ONLY
function of INULIN
- plant polysaccharide—standard used
- FREELY FILTERED and neither REABSORBED nor SECRETED by KIDNEYS
- renal clearance = GFR (~125 mL/min)
definition of RENAL CLEARANCE
- VOLUME OF PLASMA KIDNEYS can clear of a PARTICULAR SUBSTANCE in a GIVEN TIME
- used to DETERMINE GFR
define CHRONIC RENAL DISEASE
defined as GFR < 60 ml/min for THREE MONTHS
describe RENAL FAILURE
- defined as GFR < 15 ml / min
- causes UREMIA:
- IONIC AND HORMONAL IMBALANCE + METABOLIC ABNORMALITIES + TOXIC MOLECULE ACCUM.
- causes UREMIA:
what is the CHEMICAL COMPOSITION OF URINE and its NITROGENOUS WASTES
- CHEMICAL COMPOSITION:
-
95% WATER + 5% SOLUTES
- NITROGENOUS WASTES:
- UREA (from AMINO ACID BREAKDOWN)—largest SOLUTE COMPONENT
- URIC ACID (from NUCLEIC ACID METABOLISM)
- CREATININE (a metabolite of CREATINE PHOSPHATE)
- NITROGENOUS WASTES:
-
95% WATER + 5% SOLUTES
describe URINE’S PHYSICAL CHARACTERISTICS
- CLEAR:
- cloudy may INDICATE URINARY TRACT INFECTION
- PALE to DEEP YELLOW from UROCHROME
- ODOR:
- slightly aromatic when FRESH
- pH:
- urine is SLIGHTLY ACIDIC (pH 6 with RANGE of 4.5 to 8.0)
- SPECIFIC GRAVITY:
= 1 ratio of MASS OF SUBSTANCE to MASS OF EQUAL VOLUME of WATER
what are the THREE LAYERS OF THE URETER
- MUCOSA
- innermost layer—made up of TRANSITIONAL EPITHELIUM
- MUSCULARIS
- propels URINE INTO BLADDER—peristalsis
- responds to STRETCH
- ADVENTITIA
- the outermost layer—outer FIBROUS CONNECTIVE TISSUE
describe the RENAL CALCULI
-
KIDNEY STONES in RENAL PELVIS
- crystallized calcium, magnesium, or uric acid salts
- LARGE STONES begin to BLOCK THE URETER—causing PRESSURE and PAIN
describe the URINARY BLADDER
- a muscular sac—stores URINE TEMP.
- found in RETROPETRIONEUM
definition of TRIGONES
- where ureters connects
- where UTIs most commonly manifest
define the DETRUSOR MUSCLE
- made up to THREE LAYERS OF SMOOTH MUSCLE
- collapses when EMPTY—see the RUGAE
describe the URETHRA
- URETHRAS:
- muscular tube that DRAINS URINARY BLADDER
- LINING EPITHELIUM:
- consists of mostly PSEUDOSTRATIFIED COLUMNAR EPITHELIUM except;
- TRANSITIONAL EPITHELIUM near the bladder
- STRATIFIED SQUAMOUS EPITHELIUM near EXTERNAL URETHRAL ORIFICE
- consists of mostly PSEUDOSTRATIFIED COLUMNAR EPITHELIUM except;
what are the SPHINCTERS?
- INTERNAL URETHRAL SPHINCTER:
- involuntary (smooth muscle) at BLADDER-URETHRA JUNCTION
- contracts to OPEN
- EXTERNAL URETHRAL SPHINCTER:
- the voluntary (skeletal) muscle surrounding URETHRA as it PASSES THROUGH PELVIC FLOOR
what are the THREE REGIONS OF THE URETHRA?
- PROSTATIC URETHRA
- INTERMEDIATE PART OF URETHRA (MEMBRANOUS URETHRA)
- SPONGY URETHRA
describe UTI
- caused by IMPROPER TOILET HABITS;
- such as wiping back to front after defecation
- the SHORT URETHRA of FEMALES can ALLOW FECAL BACTERIA to easily ENTER THE URETHRA
- such as wiping back to front after defecation
- most UTIS seen in SEXUALLY ACTIVE WOMEN
definition of URETHRITIS
the INFLAMMATION OF URETHRA
definition of CYSTITIS
the INFLAMMATION OF BLADDER
what are the THREE EVENTS NEEDED for MICTURITION?
- MICTURITION:
- called URINATION or VOIDING
- THREE SIMULTANEOUS EVENTS must occur:
- CONTRACTION of DETRUSOR by ANS
- the OPENING of the INTERNAL URETHRAL SPHINCTER by the ANS
- opening of EXTERNAL URETHRAL SPHINCTER by the SOMATIC NERVOUS SYSTEM
where do the KIDNEYS arise from?
the MESODERM
