The Urinary System Part 2 Flashcards
1
Q
how can FILTRATE BE REABSORBED?
A
- 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
2
Q
describe PARACELLULAR REABSORPTION
A
- 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)
3
Q
describe TRANSCELLULAR REABSORPTION
A
- directly through the tubule cells
- going through APICAL MEMBRANE
- enters through CYTOSOL—exiting BASOLATERAL SIDE»_space;> enters the BLOOD
4
Q
describe TUBULAR REABSORPTION of SODIUM
A
- 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
5
Q
how does TRANSPORT OCCUR across the APICAL MEMBRANE
A
- NA+ enters TUBULE CELL at APICAL SURFACE:
- SECONDARY ACTIVE TRANSPORT (COTRANSPORT) via FACILITATED DIFFUSION through CHANNELS
6
Q
describe the ACTIVE PUMPING of NA+ (across the BASOLATERAL MEMBRANE)
A
- 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
7
Q
describe SODIUM REABSORPTION
A
through PRIMARY ACTIVE TRANSPORT provides ENERGY and means for REABSORBING almost every other substance
8
Q
how are ORGANIC NUTRIENTS REABSORBED?
A
- organic nutrients reabsorbed by SECONDARY ACTIVE TRANSPORT are COTRANSPORTED with NA+
- have a specific APICAL CARRIER; moves SODIUM DOWN ITS CONCENTRATION GRADIENT
9
Q
how is WATER REABSORBED?
A
- reabsorbed by OSMOSIS
- aided by WATER-FILLED PORES called AQUAPORINS
10
Q
describe OBLIGATORY AND FACULATIVE WATER REABSORPTION
A
- OBLIGATORY WATER REABSORPTION:
- AQUAPORINS are always present in PCT
- FACULTATIVE WATER REABSORPTION:
- AQUAPORINS are inserted in collecting ducts only if ADH is present
11
Q
what is the TRANSPORT MAXIMUM
A
- 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
12
Q
where is the site of the MOST REABSORPTION?
A
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
13
Q
describe the NEPHRON LOOP–and its LIMBS OF REABSORPTION
A
- NEPHRON LOOP:
- DESCENDING LIMB: H20 can leave, solutes cannot
- ASCENDING LIMB: H20 cannot leave, solutes can
14
Q
how is REABSORPTION in the DCT and COLLECTING DUCT, and what are the FOUR HORMONES that affect its REABSORPTION?
A
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
15
Q
describe TUBULAR SECRETION
A
- 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
16
Q
describe the COUNTERCURRENT MULTIPLER
A
- interaction of FILTRATE FLOW in ASCENDING/DESCENDING LIMBS of NEPHRON LOOPS of JUXTAMEDULLARY NEPHRONS
- creates the GRADIENT
17
Q
describe the COUNTERCURRENT EXCHANGER
A
- 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
18
Q
what is the relationship between the COUNTERCURRENT MULIPLER and EXCHANGER?
A
both work in UNISON — allows to VARY URINE CONCENTRATIONS
- always have a CONSTANT DIFFERENCE of 200 MOSM
19
Q
function of the VASA RECTA
A
- VASA RECTA:
- preserves MEDULLARY GRADIENT
- prevents RAPID REMOVAL of SALT FROM INTERSTITIAL SPACE
- removes REABSORBED WATER
20
Q
describe the formation of DILUTION
A
- 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
21
Q
function of a URINALYSIS
A
-
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
22
Q
function of INULIN
A
- plant polysaccharide—standard used
- FREELY FILTERED and neither REABSORBED nor SECRETED by KIDNEYS
- renal clearance = GFR (~125 mL/min)
23
Q
definition of RENAL CLEARANCE
A
- VOLUME OF PLASMA KIDNEYS can clear of a PARTICULAR SUBSTANCE in a GIVEN TIME
- used to DETERMINE GFR
24
Q
define CHRONIC RENAL DISEASE
A
defined as GFR < 60 ml/min for THREE MONTHS
25
describe RENAL FAILURE
- defined as **GFR < 15 ml / min**
- causes **UREMIA:**
- **IONIC AND HORMONAL IMBALANCE + METABOLIC ABNORMALITIES + TOXIC MOLECULE ACCUM**.
26
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 COMPONEN**T
- **URIC ACID** (from **NUCLEIC ACID METABOLISM)**
- **CREATININE** (a metabolite of **CREATINE PHOSPHATE)**
27
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
28
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**
29
describe the RENAL CALCULI
- **KIDNEY STONES in RENAL PELVIS**
- **crystallized calcium, magnesium, or uric acid salts**
- LARGE STONES begin to B**LOCK THE URETER—causing PRESSURE and PAIN**
30
describe the URINARY BLADDER
- a muscular sac—**stores URINE TEMP.**
- found in RETROPETRIONEUM
31
definition of TRIGONES
- where ureters connects
- where UTIs most commonly manifest
32
define the DETRUSOR MUSCLE
- made up to **THREE LAYERS OF SMOOTH MUSCLE**
- collapses when **EMPTY—see the RUGAE**
33
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 ORIFIC**E
34
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**
35
what are the THREE REGIONS OF THE URETHRA?
1. PROSTATIC URETHRA
2. INTERMEDIATE PART OF URETHRA (MEMBRANOUS URETHRA)
3. SPONGY URETHRA
36
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**
- most UTIS seen in SEXUALLY ACTIVE WOMEN
37
definition of URETHRITIS
the INFLAMMATION OF URETHRA
38
definition of CYSTITIS
the INFLAMMATION OF BLADDER
39
what are the THREE EVENTS NEEDED for MICTURITION?
- MICTURITION:
- called URINATION or VOIDING
- THREE SIMULTANEOUS EVENTS must occur:
1. **CONTRACTION of DETRUSOR by ANS**
2. **the OPENING of the INTERNAL URETHRAL SPHINCTER by the ANS**
3. **opening of EXTERNAL URETHRAL SPHINCTER by the SOMATIC NERVOUS SYSTEM**
40
where do the KIDNEYS arise from?
the MESODERM
