Renal 2- The Urinary System Functional Anatomy and Urine Formation by the Kidneys

Question 1

what are the renal functions

Answer 1

• regulation of water and electrolyte balance
• regulation of arterial pressure
• regulation of solute concentrations (osmolarity)
• excretion of metabolic waste products and foreign chemicals
• erythropoiesis via erythropoietin
• regulation of acid- base balance
• regulation of active vitamin D (calcitriol) production
• gluconeogenesis

Question 2

what metabolic waste products and foreign chemicals are the kidneys responsible for regulating

Answer 2

• urea, uric acid, creatinine, bilirubin
• drugs, pesticides, food additives

Question 3

kidney will increase or decrease excretion rate of a substance to match ____

Answer 3

input

Question 4

___ period of time between disturbance and balance

Answer 4

small

Question 5

describe the position of the kidneys in the body cavity

Answer 5

retroperitoneal

Question 6

what is the medulla of the kidneys composed of

Answer 6

-renal pyramids
- renal columns

Question 7

what do renal pyramids contain

Answer 7

• nephrons
  -border of cortex/medulla
  -papilla

Question 8

what is the functional unit of the kidney and what does it do

Answer 8

-nephron: produces urine

Question 9

what is the pathway of urine

Answer 9

minor calyx -> major calyx -> renal pelvis -> ureter -> urinary bladder -> micturition reflex

Question 10

what do the walls of the ureters contain

Answer 10

smooth muscle

Question 11

describe peristalsis in the ureters

Answer 11

-calyces stretched by urine
- initiates peristaltic wave that flows through pelvis, along ureter to bladder

Question 12

what type of nerves alter peristalsis

Answer 12

autonomic

Question 13

what does the PNS do to peristalsis? SNS?

Answer 13

• PNS: increases it
• SNS: decreases it

Question 14

what do the ureters enter the bladder through

Answer 14

the detrusor muscle

Question 15

what does the muscle tone of the detrusor muscle do to the ureter

Answer 15

compresses ureter and prevents back flow of urine during micturition

Question 16

what does the peristaltic wave do to the ureter

Answer 16

increase pressure within the ureter, opening ureter lumen, allowing urine to flow into bladder

Question 17

what is the vesicoureteral reflux

Answer 17

-backflow of urine into ureter
- enlargement of ureters
-increase pressure and damage to renal pevlis

Question 18

what type of innervation do the ureters have

Answer 18

rich pain innervation

Question 19

what is the ureterorenal reflex

Answer 19

-ureters blocked (ex: stone)
- reflex to reduce RBF and urine formation
-protective

Question 20

what type of muscle is the detrusor muscle and what junctions does it contain for cell communication

Answer 20

-smooth muscle
- gap junctions conduct APs

Question 21

what type of muscle is the internal sphincter and what does it do

Answer 21

• smooth muscle and elastic tissue
• intrinsic tone
• prevents bladder emptying under pressure increases to threshold

Question 22

what type of muscle is the external urethral sphincter

Answer 22

voluntary

Question 23

what do visceral sensory neurons in the pelvic nerves detect

Answer 23

degree of bladder stretch

Question 24

what do parasympathetic neurons in the pelvic nerves do

Answer 24

stimulate contraction of detrusor muscle and relaxation of internal sphincter

Question 25

what is the pudendal nerve and what does it do

Answer 25

somatic motor neurons controlling external sphincter

Question 26

what do sympathetic neurons in the pelvic nerves do

Answer 26

control bladder blood vessels

Question 27

describe the micturition reflex (stimulus, reflex receptor, afferent, integrating center, efferent, effector, effector response, feedback type)

Answer 27

-stimulus: bladder stretch - reflex receptor: stretch receptors in the bladder wall - afferent: visceral sensory - IC: spinal cord (spinal reflex) - efferent: parasympathetic -effector: detrusor smooth muscle - effector response: local- contractions. systemic= stretch - feedback: positive

Question 28

describe the pattern of the micturition reflex

Answer 28

-after time reflex fatigues and ceases and bladder relaxes - if bladder not emptied, reflex goes away then occurs again - frequency and power of contractions increases as bladder fills - once powerful enough, inhibits pudendal nerve to override voluntary control, allows urine to flow

Question 29

what happens in voluntary urination

Answer 29

- contract abdominal muscles - increases bladder pressure - activates micturition reflex with voluntary relaxation of external urethral sphincter

Question 30

what percentage of CO goes to the kidney

Answer 30

20%

Question 31

what does the renal artery branch off of

Answer 31

aorta

Question 32

where does the renal artery enter the kidney

Answer 32

at the hilum

Question 33

describe the renal microcirculation in general

Answer 33

two arterioles and two capillary beds

Question 34

describe glomerular microcirculation

Answer 34

- high pressure for filtration - afferent and efferent arteriolar resistance can be altered to alter Pc in glomerular capillaries

Question 35

describe peritubular microcirculation

Answer 35

-low pressure -secretion and reabsorption

Question 36

what is the pathway of microcirculation

Answer 36

-afferent arteriole -> glomerular capillaries -> efferent arteriole -> peritubular capillaries -> venules

Question 37

what is the order of flow through the nephron

Answer 37

-glomerulus - bowmans space -PCT -Proximal straight tubule (PST) - descending loop of henle - thin ascending loop of henle - thick ascending loop of henle - distal convoluted tubule (DCT) -cortical collecting duct - medullary collecting duct

Question 38

each collecting duct collects fluid from about _____ nephrons

Answer 38

4000

Question 39

____collecting ducts per kidney

Answer 39

250

Question 40

_____ nephrons per kidney

Answer 40

1,000,000

Question 41

what are the two classes of nephrons and what is the percentage of both

Answer 41

-cortical (70-80%) - juxtamedullary (20-30%)

Question 42

describe cortical nephrons

Answer 42

-glomerulus in outer cortex - short loops of henle -peritubular capillaries

Question 43

describe juxtamedullary nephrons

Answer 43

- glomerulus near cortex/medulla border -long loop of henle (extends deep into medulla) - vasa recta

Question 44

what is the role of juxtamedullary nephrons

Answer 44

concentrates urine

Question 45

where and how does filtration occur

Answer 45

- in glomerular capillaries - occurs via bulk flow

Question 46

how goes glomerular filtrate differ to plasma

Answer 46

exact same except glomerular filtrate has no proteins

Question 47

what is GFR

Answer 47

rate of filtrate production

Question 48

what is reabsorption and where does it occur

Answer 48

removes wanted substances from glomerular filtrate and puts it back into blood in peritubular capillaries -passive and active transport processes across nephron epithelium

Question 49

what is secretion and where does it occur

Answer 49

- removal of unwanted substances still in plasma and secrete it into glomerular filtrate in nephron - passive and active transport processes across nephron epithelium

Question 50

what is excretion and where does it occur

Answer 50

-removal of metabolic waste -urine exits collecting duct into minor calyx

Question 51

what is the amount of sodium filtered, reabsorbed and excreted per day

Answer 51

- filtered: 25,560 - reabsorption: 25, 410 - excreted: 150

Question 52

why do we filter so much and then expend so much energy to return greater than 99% back to the ECF

Answer 52

we filter because we want to get rid of unwanted substances and return all the good stuff