Lab #8: Renal Physiology

Question 1

How do the kidneys achieve homeostasis?

Answer 1

They achieve this homeostasis by
regulating the pH and concentration of ions and water in the various body fluids and they also provide for the elimination of the waste products of metabolism

Question 2

How many nephrons are in the kidneys?

Answer 2

1 million

Question 3

What 2 structures do nephrons contain?

Answer 3

renal corpuscle and renal tubule

Question 4

what, where, and how fast is blood first filtered through?

Answer 4

a tuft of capillaries in the glomerulus at a rate of 120 ml/min

Question 5

What is the renal tubule made up of?

Answer 5

1. Proximal convoluted tubule (PCT)
2. Nephron loop (Loop of Henle)
3. Distal convoluted tubule (DCT)

Question 6

Tubular filtrate

Answer 6

similar to blood plasma in composition except that large molecules over 70,000 MW are excluded (e.g., plasma proteins)

Question 7

What is retained in the filtrate?

Answer 7

Toxic by-products of metabolism and excess substances, such as salt, are retained in the filtrate and are finally excreted in the urine (approximately 1 ml of urine formed per minute)

Question 8

what does the final composition of urine reflect?

Answer 8

the final composition of urine is quite different from that of the glomerular filtrate and reflects the integrity of kidney function and changes in blood composition.

Question 9

an analysis of urine

Answer 9

urinalysis

Question 10

phenylketonuria (PKU)

Answer 10

genetically unable to metabolize the amino acid phenylalanine

Question 11

if accumulated in the body, phenylalanine is converted into what?

Answer 11

phenylpyruvic acid

Question 12

An accumulation of phenylalanine in individuals with PKU can result in

Answer 12

developmental delays, seizures, and intellectual impairments

Question 13

Individuals with _________ _________ , have either an imbalance or a deficit in the amount of insulin produced by the pancreas

Answer 13

diabetes mellitus (commonly referred to simply as diabetes)

Question 14

fatty acid metabolites

Answer 14

ketones

Question 15

an increase in ketones causes the pH to _______

Answer 15

decrease

Question 16

what is indicative of diabetes mellitus?

Answer 16

The presence of both glucose and ketones in the urine combined with a low urine pH

Question 17

a combined test of urinary pH, protein, glucose, ketones, and occult blood

Answer 17

Labstix Test

Question 18

The normal pH value of urine

Answer 18

~ 6 (can range from 4.5-8.0)

Question 19

The normal protein value of urine

Answer 19

none or trace

Question 20

The normal glucose, ketone, and occult blood level of urine

Answer 20

none

Question 21

What makes the pH of urine more acidic?

Answer 21

a diet rich in proteins or can result from respiratory disorders, dehydration, or starvation

Question 22

Alkaline urine

Answer 22

can result from a diet rich in citrus fruits and dairy, vomiting, urinary tract infections

Question 23

Cystitis

Answer 23

urine decomposes in the bladder with the production of ammonia

Question 24

the presence of protein in the urine

Answer 24

proteinuria or albuminuria

Question 25

high glucose levels in the urine

Answer 25

glycosuria

Question 26

Abnormally large amounts of ketone excretion

Answer 26

ketonuria

Question 27

ketonuria suggest that the body is using fat as an energy source as opposed to glucose and can…

Answer 27

indicate either diabetes mellitus or starvation

Question 28

blood not visible to the naked eye

Answer 28

Occult blood

Question 29

Blood present in the urine can indicate that an individual has

Answer 29

a urinary tract infection, kidney stones, or cancerous cells

Question 30

a disease in which the glomeruli are damaged and plasma proteins and erythrocytes leak into the nephrons

Answer 30

nephritis

Question 31

individuals with nephritis will have….

Answer 31

blood present in their urine as well as high levels of protein

Question 32

One of the kidney’s main functions is to

Answer 32

regulate the osmolarity of the body fluids at around 300 milliosmoles per liter to ensure the cells, particularly those in the brain, do not shrink or swell

Question 33

if an individual is dehydrated,

Answer 33

they will produce a small amount of highly concentrated urine

Question 34

If an individual is overhydrated,

Answer 34

they will produce a large amount of minimally concentrated (dilute) urine

Question 35

Specific Gravity

Answer 35

The ratio of the density of a substance compared to the density of distilled water

Question 36

The urinometer is calibrated to give a correct reading only if the urine is at

Answer 36

15 degrees celcius

Question 37

If your urine is at a different temperature, you will need to correct the specific gravity value by

Answer 37

adding 0.001 for every 3 degrees celcius above, or by
subtracting 0.001 for every 3 degrees celcius below the calibration temperature (15 degrees celcius)

Question 38

The normal range of urine specific gravity is

Answer 38

1.0015 to 1.035

Question 39

low specific gravity reading

Answer 39

found in individuals with chronic nephritis (slow, onset kidney disease)

Question 40

high specific gravity

Answer 40

is observed in acute nephritis (sudden, onset kidney disease)

Question 41

Mohr Method (NaCl Concentration)

Answer 41

The process of titrating silver nitrate to analyze the presence of chloride ions in a substance using potassium chromate as an indicator

Question 42

In the Mohr Method, you add first

Answer 42

one drop of 20% potassium chromate to the test tube

Question 43

In the Mohr method, you add second

Answer 43

2.9% silver nitrate solution drop by drop to the test tube

Question 44

Each drop of 2.9% silver nitrate added to produce the
reddish-brown colored solution represents

Answer 44

1 g/liter of NaCl present in the urine