test 6 part 2

Question 1

Renal function big picture

Answer 1

 Control volume and composition of body fluids (control sodium concentration)
 Maintains environment cells need for proper function
 Rid body of waste materials produced by body or ingested

Question 2

process of the kidneys to keep volume distribution and rid body of waste (3 things)

Answer 2

 Filter the plasma (into tubules)
-everything designed to keep filtration CONSTANT
 Reabsorb much of the filtrate (move from tubules back to blood)
 Secrete some substances (Move from blood into tubules)
 Substances that are secreted or not reabsorbed are excreted in the urine

Question 3

Glomerular capillaries have 1 function

Answer 3

-filtration

Question 4

Solute concentration in Bowman’s capsule is same as what

Answer 4

-patients blood

Question 5

Reabsorption takes place in

Answer 5

• proximal tubule
• distal tubule (determines how much of a substance is actually absorbed)
• collecting duct
• loop of henle

Question 6

loop of henle determines what

Answer 6

-if urine will be dilute or concentrated

Question 7

Reabsorption pathway

Answer 7

Tubule -> interstitial space -> capillary

• diffusion
• straight through the cell or through gaps

Question 8

secretion pathway

Answer 8

Capillary -> interstitial space -> tubule

• usually an active process
• creates gradient
• H+ ions secreted (kidneys play major role in acid base balance)

Question 9

Renal Function – More Specific

Answer 9

 Excretion of metabolic waste products and foreign chemicals
 Regulation of water and electrolyte balances*
 Regulation of body fluid osmolality and electrolyte* concentrations
 Regulation of blood pressure*
 Regulation of acid-base balance*
 Secretion, metabolism, and excretion of hormones
 Gluconeogenesis

Question 10

Primary way metabolic waste products are removed from the body

Answer 10

 Urea: amino acid metabolism
 Creatinine: from muscle creatine (mainly with skeletal muscle)
 Creatine used to create phosphocreatine which serves as energy source for production of ATP in muscle. Each day 1 to 2% of muscle creatine converted to creatinine.
 Uric acid: from nucleic acids
 End products of hemoglobin break down (bilirubin)
 Hormone metabolites
 Most toxins / foreign
 Pesticides / drugs / food additives

Question 11

Water & Electrolyte Regulation

Answer 11

 Fluid / salt intake usually depends on individual eating / drinking habits
 Kidneys must respond to changes in intake
 Able to respond to huge differences in sodium intake with relatively small changes in ECF volume or [Na+]
 10 mEq/day to 1500 mEq/day
 Also true for most other electrolytes

Question 12

Kidneys work with lungs and body-buffer systems

Answer 12

 Lungs remove carbon dioxide
 Kidneys control hydrogen ion and bicarbonate concentration
 Kidneys only way to remove sulfuric and phosphoric acid
 Byproducts of protein metabolism

Question 13

Regulation Erythrocyte Production

Answer 13

 Kidneys secrete erythropoietin (almost all) – which stimulates red blood cell production
 Hypoxia major stimulus for production
 Patient’s with severe renal disease will develop severe anemia due to lack of erythropoietin production

Question 14

Glucose Synthesis

Answer 14

 During prolonged fasting, new glucose is produced from amino acids and other items
 Significant quantities can be produced

Question 15

Renal Blood Supply

Answer 15

 RBF = 22% of CO
 1100 mls/minute
 Glomerular Capillaries
 High pressure (60 mmHg) produces high rate of fluid filtration
 Peritubular Capillaries
 Low pressure (13 mmHg) produces high rate of fluid reabsorption
 Control of afferent and efferent arteriole
resistance

Question 16

Nephron

Answer 16

 Number of nephrons and effect of aging
 Up to 1 x 10^6
 > 40 years lose 10% every 10 years
 Merging of collecting ducts

Question 17

Cortical vs Juxtamedullary Nephrons

Answer 17

 20 to 30% of all nephrons are juxtamedullary nephrons

Question 18

Filling/emptying of the urinary bladder

Answer 18

 Nervous reflex – micturition reflex empties bladder

 Autonomic spinal cord reflex with input from centers in cerebral cortex or brain stem

Question 19

physiologic anatomy of bladder

Answer 19

 Smooth muscle – detrusor muscle
 Trigone (trahy-gohn) – very smooth
 Internal sphincter – tone holds urine in bladder (smooth muscle)
 External sphincter – skeletal muscle – voluntary control by nervous system – conscious prevention of urination

Question 20

Pelvic nerves provide primary supply

Answer 20

 Sensory and motor fibers
 Sensory fibers from posterior urethra responsible for initiating micturition reflex
 Motor fibers are parasympathetic

Question 21

Pudendal nerve

Answer 21

– skeletal muscle fibers

provide voluntary control of external sphincter

Question 22

Sympathetic control via

Answer 22

• hypogastric nerves

- control of blood vessels

Question 23

Ureters Innervation

Answer 23

 Ureters well supplied with pain nerves – stimulated when blocked ureters respond with intense reflex constriction which sends sympathetic stimulation back to kidneys to constrict renal arterioles [ureterorenal reflex]

Question 24

Transport of Urine to Bladder

Answer 24

 Composition of urine does not change once it leaves the collecting ducts
 Renal calyces act as pacemaker for peristaltic contraction of smooth muscle forcing urine down into the renal pelvis, down the ureters into the bladder
 Increased stretch of calyces increases peristaltic rate
 Innervated by parasympathetic (enhances peristalsis) and sympathetic (inhibits peristalsis) nerves
 Detrusor muscle prevents backflow from bladder to ureters (especially during bladder contraction)
 Peristaltic waves down ureter increases pressure within ureter to open passage to bladder
 If ureter is not long enough to pass through wall of bladder, reflux will occur

Question 25

Micturition Reflex

Answer 25

 Diagram shows relationship between bladder volume and internal pressure  Pressure spikes – micturition contractions stimulated by stretch receptors in bladder wall  Provides positive feedback to stretch receptors resulting in further increase in pressure -as the volume of the bladder goes up, the P goes up -the more stretch = the more it will contract  Once micturition reflex is strong enough it stimulates inhibitor signals to the external sphincter  Urination occurs when inhibitor signals are stronger than the voluntary constrictor signals being sent to external sphincter -SO as the bladder gets fuller and fuller it is being stimulated more and more to contract -once strength of contractions great enough, it stimulates inhibitors of the sphincter muscles resulting in urination