urinary system

Question 1

What organs make-up the urinary system and what are their functions?

Answer 1

Kidney= filters blood and excretes toxic metabolic wastes, regulates blood volume, pressure, and osomolarity, regulate electrolyte + acid-base balance, secrete erythoprotein, regulate calcium homeostasis, clear hormones and drugs,
Ureter= carry urine from kidneys to bladder
Bladder= stores urine
Sphincter= internal urethral sphincter (only present in males) function is to prevent refulux of semen into bladder during ejaculation. external urethral sphincter= provides voluntary control over the voiding of urine
Urethra= let urine pass out of body

Question 2

What is a metabolic waste? List two major nitrogen waste products. What is azotemia?

Answer 2

metabolic waste= waste substance produced by the body
major nitrogen waste produts= urea (by product of protein catabolism, and ammonia
azotemia= elevated blood urea nitrogen BUN, may indicate renal insufficiency

Question 3

What organ systems are for excretion?

Answer 3

excretion= separation of wastes from body fluids and their
elimination
respiratory system, integumentary system, digestive system, urinary system

Question 4

What organs of the urinary system are retroperitoneal?

Answer 4

kidneys, ureters, urinary bladder, renal artery and vein, and adrenal glands

Question 5

What are the functional units in kidneys and how many are in each kidney?

Answer 5

nephrons
1.2 million nephrons in each kidney

Question 6

How do “three layers” of connective tissue protect the kidneys?

Answer 6

reanl fascia= binds it to abdominal wall
perirenal fat= cushions kidney and holds it into place
fibrous capsule= encloses kidney protecting it from trauma and infection

Question 7

what organ produces what substance? how it effects in bringing the blood pressure back to normal? (slider 23)

Answer 7

Kidney= produces renin
Liver= produces angiotensinogen
lungs= produce angiostetin converting enzyme

Angiotensinogen is sent to the hypothalamus, vacoconstriction, and adrenal cortex in kidney which elevates blood pressure

Question 8

How is the renal parenchyma organized?

Answer 8

renal parenchyma= forms the urine
encircles the renal sinus which occupies blood and lymphatic vessels, nerves

Question 9

How are the nephrons arranged in the kidney?

Answer 9

juxtamedullary nephrons= ones close to medulla, long nephron loops (15% of nephrons)
cortical nephrons= ones farther from medulla, short nephron loops (85% of nephrons)

Question 10

What are the various phases in urine formation? Where do these events occur?

Answer 10

1. Glomerular filtration= process in which water and some solutes in the blood plasma pass from capillaries of the glomerulus into the capsular space of the nephron (occurs in kidneys)
2. Reabsorption and secretion= tubular reabsorption (proximal tubule) is the process of reclaiming water and solutes from the tubular fluid and returning them to the blood
   tubular secretion is the process by which the renal tubule extracts chemicals from the capillary blood and secretes them into the tubular fluid (nephron)
3. Water conservation= This process conserves water and concentrates urine (kidney)

Question 11

Which vessels bring the blood to the glomerulus and which carry blood away from the
glomerulus?

Answer 11

afferent= vessels bring blood to glomerulus
efferent= vessels bring blood away from glomerulus

Question 12

What type of molecules pass freely through filtration membrane?

Answer 12

any molecule smaller than 3nm
water, electrolytes, glucose, fatty acids, amino acids, nitrogenous wastes, and vitaminds

Question 13

What is the glomerular net filtration pressure (NFP) and what are the three forces that
determine the NFP?

Answer 13

10 mm Hg
blood hydrostatic pressure
colloid osmotic pressure
capsular pressure

Question 14

What is the glomerular filtration rate? How much urine on average is excreted by an adult?

Answer 14

glomerular filtration rate= the amount of filtrate formed per minute by the two kidneys combined
young adult male= 125 mL filtrate per minute
young adult female= 105 ml/min
1 to 2 L excreted per day by an adult, 99% of the filtrate is reabsorbed

Question 15

What are the names of the two mechanisms of autoregulation? Know the cells involved and
their role in autoregulation

Answer 15

renal autoregulation= Ability of nephrons to adjust their own blood flow

myogenic mechanism= based on the tendency of smooth muscle to contract
when stretched

tubuloglomerular feedback= glomerulus receives feedback on the status of the downstream tubular fluid and adjusts filtration to regulate its composition, stabilized nephron performance, and compensate for flucations in blood pressure
in systemic blood pressure

Three cells involved
Macula densa= these cells absorb Na+, K+, Cl- and water follows osmotically

Juxtaglomerular cells= constrict arterioles when stimulated by macula,

Mesangial cells= build matrix for glomerulus, constrict/relax capillaries to regulate flow

Question 16

What is the role of rennin-angiotensinogen-aldosterone mechanism in regulating BP?

Answer 16

when there is a drop in blood pressure renin is released by the kidneys into the blodstram , and angiotensinogen comes from the liver. it then becomes angiotensin I and then angiotensin II from the lungs being sent to the hypothalamus, cardiovascular system, and adrenal gland in the kidney.
Elevated blood pressure begins to occur

Question 17

What is the difference between glomerular filtrate, tubular fluid and urine?

Answer 17

glomerular filtrate= fluid in the capsular space, like blood plasma but has no protein
tubular fluid= fluid from the proximal convoluted tube, differs from glomerular filtate because of substances removed and added by tubule cells
urine= called urine once its in the collecting duct

Question 18

In anatomy and physiology, we know structure “suggests” function. Explain why this is true
with the proximal convoluted tubules

Answer 18

proximal convoluted tubles= reabsorbs 65% of glomerular filtrate and removes substances from blood and secretes them into the tubule for disposal in the urine

Question 19

What are the two routes for reabsorption at PCT?

Answer 19

tubular reabsorption= process of reclaiming water and solutes from the tubular fluid and returning them to the blood
transcellular route= substances pass through cytoplasm
paracellular route= substances pass through gaps between cells

Question 20

What are antiport and symport and what is their role at the PCT?

Answer 20

antiport= protein that moves two or more solutes in opposite directions, pulls Na+ into the cell while pumping H+ out of it
symport= protein that moves two solutes in the same direction, symport bind Na+ to another solute
They are responsible for sodium uptake

Question 21

What is the water channel called?

Answer 21

aquaporins

Question 22

What is glycosuria? Explain this condition in terms of tubular reabsorption and the glucose
transport maximum inde

Answer 22

glycosuria= blood glucose levels above 220 mg/dl

Question 23

What is tubular secretion?

Answer 23

tubular secretion is the process by which the renal tubule extracts chemicals from the capillary blood and secretes them into the tubular fluid (nephron)

Question 24

The distal convoluted tubule cells need to absorb about 34 Liters of water every day from
the glomerular filtrate. What are the two different type of cells found at DCT? What is the
function of each cell type?

Answer 24

Principal cells= involved in salt and water balance
Intercalated cells= involved in acid-base balance by secreting H+ and reabsorbing K+

Question 25

Which four hormones play an important role in water conservation and regulation of BP?
Where are these hormones formed and what is their action?

Answer 25

Aldosterone= salt retaining hormone, secreted by the adrenal cortex
Atrial natriuretic peptide= heart secretes in response to high BP
ADH= secreted by posterior lobe of pituitary in response to dehydration and rising blood osmolarity
parathyroid hormone= secerted from parathyroid glands in response to calcium deficiency

Question 26

How is the function of the PCT and DCT different?

Answer 26

PCT= reabsorption
DCT= secretion

Question 27

The collecting ducts make it possible to create
hypertonic urine. What factors make this possible?

Answer 27

the factors that make this possible are
1. the osmolarity of the extracellular fluid is four times as high in the lower medulla as it is in the cortex
2. medullary portion of CD is more permeable to water than to solutes

Question 28

What is water diuresis? What happens when you are dehydrated?

Answer 28

water diuresis= when you drink too much water a large amount of hypotonic urine is made
dehydration= urine is more concentrated, ADH is released and increases water reabsorption (reduces urine output)

Question 29

What is a countercurrent multiplier and where is it located? What is the range of osmolarity
created by this system?

Answer 29

countercurrent multiplier= multiplies the osmolarity deep in the medulla and moves fluid flowing in opposite directions
nephron loop acts as a countercurrent multiplier

Question 30

What is urinalysis? What is the normal appearance, odor, specific gravity, osmolarity, pH,
chemical composition of urine?

Answer 30

urinalysis= the examination of the physical and
chemical properties of urine
appearance= clear, almost colorless to deep yellow
odor= bacteria degrade urea into ammonia
specific gravity= similar to distilled water
osmolarity= Ranges from 50 mOsm/L hydrated to 1,200 mOsm/L in dehydrated
person
pH= range: 4.5 to 8.2, usually 6.0 (mildly acidic
chemical composition= 95% water, 5% solutes

Question 31

What is normal urine volume? What is Polyuria, Oliguria, Anuria?

Answer 31

normal volume of urine is 1 to 2 L a day
Polyuria= output in excess of 2 L/day
Oliguria= output of less than 500 mL/day
Anuria= 0 to 100 mL/day

Question 32

What is proteinuria, pyuria and hematuria? What are the causes?

Answer 32

proteinuria= presence of protein in the urine, kidney disease or distance runners and swimmers
pyuria= pus in the urine, caused by kidney infection
hematuria=blood in the urine, caused by UTI, trauma, or kidney stones, distance runners and swimmers

Question 33

What are Diuretics? How do caffeine, alcohol and loop diuretics work? Why are they
prescribed to a patient with high BP?

Answer 33

diuretic= any chemical that increases urine volume
Alcohol inhibits ADH secretion and reduces reabsorption
Diuretics are prescribed to a patient with high BP because they reduce the bodys fluid volume and blood pressure

Question 34

Explain osmotic diuresis in relationship to diabetes mellitus? How is it different from the
diuresis caused by diabetes insipidus?

Answer 34

osmotic diuresis= more water passed in the urine causing someone to be dehydrated, this is a result of hyperglycemia (high blood sugar)
diabetes insipidus results from ADH hyposecretion

Question 35

What is renal clearance? What are the use of inulin and creatinine?

Answer 35

renal clearance= volume of blood plasma from which a waste is removed in 1 minute
insulin and creatine are used to determine glomerular filtration rate
Creatine is an easier procedure than injecting and measuring insulin

Question 36

What is the anatomy of the ureters and how is urine moved into the bladder?

Answer 36

the renal pelvis funnels urine into the ureter
urine is moved into the bladder using a small flap of mucosa that acts as a valve which prevents urine from going back into the ureter when the bladder contracts

Question 37

What is cystitis, pyelitis, and pyelonephritis?

Answer 37

cystitis= infection of the urinary bladder, common in females due to short urethra
pyelitis= infection of renal pelvis
pyelonephritis= infection that reaches the cortex
and the nephrons

Question 38

What are the causes and methods of treatment for renal stones?

Answer 38

caused by hypercalcemia, dehydration, pH imbalances, UTI,
teratment= shock wave lithotrispy

Question 39

What is the voluntary and involuntary micturition reflex?

Answer 39

micturiton reflex= spinal reflex that partly controls urination
involuntary micturition reflex occurs in infants and young children because they don’t have voluntary bladder control

Question 40

What is renal insufficiency and how is it treated?

Answer 40

state in which the kidneys cant maintain homeostasis due to the destruction of nephrons
treated by CAPD and hemodialysis