A + P Urinary System

Question 1

urinary system function

Answer 1

main: rid the body of nitrogenous products and other wastes

regulate the amount of water and ions present in the body fluids

Question 2

kidneys function

Answer 2

main organ for removal of wastes and in osmotic regulation of the body fluids

Question 3

nitrogenous wastes

• AAs
• AAs can be

Answer 3

AAs construct proteins and other nitrogen-containing molecules for use by certain cells in the body
AAs can be oxidized for energy or converted to fats or carbohydrates

Question 4

when AAs are oxidized or converted to other kinds of molecules…

Answer 4

the amino (NH2) group must be removed
the nitrogen containing compounds produced as a result of protein and AA breakdown are toxic and must be removed from the body

Question 5

nitrogenous wastes are excreted in the form of

Answer 5

ammonia (NH3)
urea
uric acid

Question 6

ammonia

Answer 6

formed immediately after the amino group is removed from an AA, often in the intestines during digestion
this process requires very little energy

Question 7

urea

Answer 7

humans excrete nitrogenous wastes in the form of urea because it is less toxic than NH3 and can be moderately concentrated to conserve H2O
urea is produced in the liver by a process that requires more energy than NH3 production, but it reduces the toxicity of the waste

Question 8

uric acid

Answer 8

the end product of specific protein digestion
neither very toxic nor very soluble in water
high levels in the blood can lead to gouty arthritis or the formation of kidney stones
uric acid is excreted along with urea

Question 9

urinary system anatomy

Answer 9

kidneys
ureters
urinary bladder
urethra

Question 10

kidney function

Answer 10

primary filtration organs

Question 11

kidney structure

Answer 11

cortex
medulla
calyx
renal pelvis
nephrons

Question 12

cortex

Answer 12

outer portion

where blood is filtered via the glomeruli

Question 13

medulla

• divided into
• what happens there?

Answer 13

inner portion
divided into several pyramids/lobes
this is where the amount of Na+ and H2O in your urine is regulated (e.g. how concentrated the urine will be) via the loops of Henle

Question 14

calyx

• function
• drains to

Answer 14

urine repository from each medullar pyramid

each calyx drains into the renal pelvis

Question 15

renal pelvis

-function

Answer 15

central urine repository within the kidney before excretion through the ureter

Question 16

nephrons

Answer 16

microscopic (about 1 million/kidney), partially housed in both the cortex and medulla

Question 17

nephron composition

Answer 17

glomerulus
Bowman's Cpasule
proximal convoluted tubule (PCT)
Loop of Henle
distal convoluted tubule (DCT)
collecting duct

Question 18

glomerulus

• function
• fluid composition
• what stays in the blood vessels
• where are they housed?

Answer 18

network of capillaries from which fluid “leaks” out of the circulatory system (ultra filtration)
the fluid (ultra filtrate) is mostly water, urea, salts, minerals, and nutrients
RBC, WBC, and platelets stay in the blood vessels
the glomeruli are housed within the cortex of the kidney

Question 19

Bowman’s Capsule

• visual
• function
• location

Answer 19

a funnel-like structure that surrounds and collects ultra filtrate from the glomerulus
housed within the cortex of the kidney

Question 20

proximal convoluted tubule

• function
• location

Answer 20

reabsorbs water and nutrients, such as glucose and AAs, that leaked out of the glomerulus
housed within the cortex of the kidney

Question 21

Loop of Henle

• location
• includes
• as ultra filtrate…
• function of structure

Answer 21

extends from PCT in cortex into medulla
-includes a hairpin bend, which creates a concentration gradient for Na+ in the medulla
as ultra filtrate passed down the loop into a salty medulla, H2O is lost to the medulla and recollected in peritubular capillaries
as ultra filtrate moves back up the loop it loses Na+
the entire structure is designed to concentrate the urine for excretion

Question 22

distal convoluted tubule

• function
• location

Answer 22

passes by glomerulus and is responsible for mineral balance (save Na+ at expense of K+ or vice versa, and sometimes expel extra H+ here)
housed within the cortex of the kidney

Question 23

collecting duct

• location
• function

Answer 23

extends from cortex through medulla into calyx

delivers urine to the renal pelvis

Question 24

blood flow through the kidney

• enters through
• blood contains

Answer 24

blood enters the kidney through a branch of the aorta called the renal artery
-blood contains glucose and O2 (because the kidney works hard to produce urine) and urea (which must be removed from the blood

Question 25

blood in the renal artery - must have - may have - kidney removes

Answer 25

must have sufficient pressure or the kidney will not be able to filter the blood blood may have too much Na+ or too much H2O kidney removes whichever is in excess to maintain adequate blood volume and ion balance

Question 26

renal artery branches

Answer 26

branches into interlobular arteries, which further divide into afferent arterioles

Question 27

afferent arteriole - leads to - fluid leaks

Answer 27

leads to a network of capillaries called a glomerulus fluid leaks out of the capillaries of the glomerulus, but large molecules and cells do not fit through the pores (ultra filtration)

Question 28

blood leaves the capillaries of the glomerulus via

Answer 28

efferent arteriole

Question 29

blood from efferent arterioles enter

Answer 29

peritubular capillaries

Question 30

peritubular capillaries | -function

Answer 30

collect much of the water that was lost through the glomerulus

Question 31

interlobular veins - from - lead to

Answer 31

from the peritubular capillaries | lead to a renal vein, which exits the kidney and returns blood to the inferior vena cava

Question 32

renal vein | -blood has

Answer 32

had all of its urea removed and should have exactly the right amount of H2O and Na+

Question 33

ureters | -function

Answer 33

pathways for urine that extend from each renal pelvis to the urinary bladder

Question 34

urinary bladder | -function

Answer 34

"holding tank" for urine awaiting excretion

Question 35

urethra

Answer 35

pathway for external urine excretion

Question 36

urine production (diuresis) - glomerulus - -blood enters - -blood leaves - -ultra filtrate

Answer 36

blood enters the glomerulus via an afferent arteriole where blood pressure forces H2O and small molecules (ultra filtrate), such as urea out through the pores in the glomerular capillaries into the surrouding Bowman's capsule blood leaves the glomerulus via the efferent arteriole ultra filtrate collects in Bowman's capsule and drains into the PCT - this is the foundation of what will become urine

Question 37

Glomerular Filtration Rate

Answer 37

volume of fluid filtered from the glomerulus into Bowman's capsule per unit time calculating GFR is important for assessment of the excretory function of the kidneys

Question 38

proximal convoluted tubule | -cells have

Answer 38

cells have numerous microvilli and mitochondria, which provide surface area for reabsorption and energy

Question 39

PCT | -selective reabsorption

Answer 39

occurs from the PCT water, glucose, vitamins, important ions and most AAS are reabsorbed from the PCT back into adjacent peritubular capillaries via active transport

Question 40

a substance is no longer absorbed by the PCT when... - what happens to it? - reason - helps regulate

Answer 40

the concentration in the blood reaches a certain level -remains in the urine prevents the composition of the blood from fluctuating -process helps regulate the levels of glucose and inorganic ions such as Na+, K+, HCO3-, PO43-, and Cl-

Question 41

Loop of Henle | due to...

Answer 41

concentration gradients established in the medulla, the Loop of Henle is able to conserve H2O and further concentrate urine

Question 42

Descending Loop - has low... - consequently - removal of Na+

Answer 42

has low permeability for ions and urea, but high permeability for H2O consequently, H2O moves out of the descending loop as it passes through the area of high Na+ concentration produced by the ascending loop this removal of Na+ concentrates the urine while conserving H2O for the body

Question 43

Ascending Loop - has low - Na+ - -results - removal of H2O

Answer 43

has low permeability for H2O and ions, but high permeability for Na+ Na+ is actively pumped out in the ascending loop and H2O cannot re-enter -results in a higher concentration of Na+ in the medulla, which supports H2O removal in the descending loop this removal of H2O further concentrates the urine

Question 44

countercurrent multiplier - high Na+ - movement of Na+ - H2O loss - urea

Answer 44

high Na+ in the medulla acts to help remove H2O in the descending loop -called counter current multiplier movement of Na+ out of the ascending loop and into the medulla results in H2O loss and concentrated urine in the descending loop H2O loss and increased Na+ concentration that occurs in the descending loop further enhances the ability of the ascending loop to pump more Na+ out into the medulla urea remains concentrated in the fluid for excretion

Question 45

distal convoluted tubule (DCT) - functions - what is secreted

Answer 45

most of the minerals and salts from the ultra filtrate are reabsorbed some wastes are actively secreted into the urine -include H+, K+, toxic and foreign substances (drugs, penicillin, uric acid, creatine, creatinine)

Question 46

collecting duct - what drains into it - what do they do

Answer 46

DCT from several nephrons drain into a common collecting duct collecting ducts pass through the concentration gradient that was established by the Loops of Henle -as fluid passes through the collecting ducts, additional H2O leaves the collecting duct due to osmosis, which is the final step in the conservation of H2O and concentration of urine

Question 47

urination (micturition) - bladder filling - cerebral cortex - decision to urinate - immersiton duresis

Answer 47

as the bladder fills with urine, mechanoreceptors send APs to the spinal cord (via the pelvic nerves) and then to the pons and cerebrum of the brain cerebral cortex can override the urge to urinate, although this is a learned voluntary response when the decision to urinate occurs, the pons initiates motor nerve impulses that cause the bladder to contract and the internal and external sphincters of the urethra to open theory that you can induce urination through the immersion of the hand in water

Question 48

regulation of blood pH

Answer 48

breathing | kidneys

Question 49

breathing - adjustment - rapid breathing - slow breathing

Answer 49

adjustment of the breathing rate can make quick, but slight, alterations in the pH of the blood by reducing the amount of CO2 in the blood - rapid breathing results in more CO2 given off during ventilation, which moves the equation below to the left and increases the blood pH - slow breathing results in less CO2 given off during ventilation and the equation moves to the right, which decreases the pH

Question 50

breathing equation

Answer 50

CO2 + H2O --> H2CO3 HCO3- + H+

Question 51

kidneys - kidneys - blood pH is low - blood pH is high

Answer 51

the kidneys provide a slower, but more powerful means of regulate pH -excrete or absorb hydrogen ions and bicarbonate ions as necessary for adjusting pH (happens at the DCT) when blood pH is low, H+ is excreted into the DCT and HCO3- from the ultra filtrate/urine is reabsorbed into the blood when the pH is too high, less H+ is excreted into the DCT and less Na+ and HCO3- are reabsorbed into the blood

Question 52

hormones of the urinary system

Answer 52

Anti-Diuretic Hormone (ADH) aldosterone Atrial Natriuretic Hormone (ANH)

Question 53

Andi-Diuretic Hormone (ADH) - function - osmotic pressure of blood increases - osmotic pressure of blood decreases

Answer 53

increases the permeability of the collecting ducts - if the osmotic pressure of blood increases (too much Na+, not enough H2O), the hypothalamus stimulates the posterior pituitary gland to release ADH and the permeability of the collecting ducts will increase, which facilitates removal of H2O from the urine and absorption into the blood - if the osmotic pressure of blood decreases, the posterior pituitary does not release ADH, the permeability of the collecting duct remains low, and additional H2O is excreted in urine

Question 54

ADH | -alcohol and diuretic drugs

Answer 54

alcohol and diruetic drugs inhibit the secretion of ADH and thus increase H2O loss (and consequently lower blood pressure)

Question 55

aldosterone - function - low osmotic pressure - increased osmotic pressure

Answer 55

acts primarily on the DCT to promote Na+ absorption into the blood to regulate blood volume and blood pressure - when osmotic pressure is low, the afferent arteriole cells secrete renin - renin initiates a series of chemical reactions that ultimately stimulate the adrenal cortex to release aldosterone - increased osmotic pressure associated with increased Na+ contributes to the reabsorption of H2O from the DCT into the blood, which increases blood volume and blood pressure - in the absence of aldosterone, more Na+ is excreted and less H2O is reabsorbed from the DCT, which decreases blood volume and lowers blood pressure

Question 56

Atrial Natruiretec Hormone (ANH) - function - loss of H2O - presence of too much blood

Answer 56

inhibits the release of aldosterone and ADH, which causes the kidneys to excrete excess H2O - loss of H2O and Na+ contribute to lowered blood volume and blood pressure - presence of too much blood in the circulatory system stimulates the atria in the heart to secrete ANH

Question 57

homeostatic imbalance of the urinary system

Answer 57

``` kidney stones urinary incontinence urinary tract infection (UTI) nephrotic syndrome chronic kidney disease (CKD) ```

Question 58

kidney stones

Answer 58

renal calculus sometimes the salts and minerals (typically calcium and phosphate) in the urine crystallize in the pelvis and form a solid mass or "pebble" (usually less than 5 mm in diameter), which prevents urine from draining out of the pelvis into the ureter -can be passed (1-4 weeks) or surgically removed (10-20% of stones) for analysis of the stone composition

Question 59

urinary incontinence

Answer 59

any involuntary leakage of urine, which usually can be attributed to underlying medical conditions, such as - uncontolled diabetes - enlarged prostate - multiple sclerosis - Parkinson's disease

Question 60

urinary tract infection (UNI)

Answer 60

common bacterial infection that affects part of the urinary tract consequently, there may be pain during urination and either frequent urination or urges to urinate (or both)

Question 61

nephrotic syndrome

Answer 61

group of symptoms that include protein in the urine, low blood protein levels, high cholesterol and triglyceride levels, and swelling syndrome is caused by different disorders that damage the kidneys, including glomerulonephritis, diabetes, cancer, immune disorders, various infections, and use of certain drugs

Question 62

chronic kidney disease (CKD)

Answer 62

the slow loss of kidney function over time symptoms are often absent until kidney function is severely reduced the final stage of CKD is know as end-stage renal disease (ESRD), at which point the kidneys are no longer able to remove enough wastes and excess fluids from the body many causes of CKD, but the two most common are diabetes and high blood pressure