Intro to the Kidney (TEST 4)

urinary

Kidneys are part of the __________ system.

-excretory

-endocrine

-metabolic functions

What type of functions do the kidenys carry out?

Nephrons

What are the primary functional excretory units in the kidney?

glucose and amino acids

How does the proximal convoluted tubule reabsorb?

-Urea

-uric acid

-H+

-NH4+

-drugs/metabolites

What does the proximal convoluted tubule secrete?

-water in descending

-Na+

-Cl-

-K+ in ascending

What does the loop of henle reabsorb?

urea

What does the loop of henle secrete?

-Na+

-Cl-

-HCO3-

What does the distal convoluted tubule reabsorb?

-water

-urea

What does the distal convoluted tubule secrete?

200 L

About how much blood is filtered through a health adult kidney each day?

-glomerular filtration

-reabsorption

-tubular secretion

What are the key processes of the excretory function of the kidney?

Glomerular Filtration

-passive movement of water, ions, and small molecules (<10-20 kDa) across the glomerular capillary -> Bowman capsule -> proximal tubule

-most proteins are too large (>60 kDa)

Golmerular Filtration Rate (GFR)

rate of plasma from glomerulus into Bowman's space

>60 kDa

What size are the proteins that are too large for glomerular filtration? (think albumin)

rescuing molecules that we want to maintain within the body

What is the goal of reabsorption?

reabsorption

-brings water and solutes back through the nephron

-mostly in proximal convoluted tubule

NO

Are highly ionized compounds reabsorbed?

Tubular secretion

-active process to remove undesirable molecules

-includes transport pathways-OATPs, P-gp, OATs

facilitating elimination of undesirable molecules

What is the goal of tubular secretion?

-renin

-prostaglandins and kinins

-Erythropoietin

What are the hormones that the kidney synthesizes and secretes?

inflammatory responses

What does the production and metabolism of prostaglandins and kinins influence?

Erythropoietin (EPO)

is produced and secreted by peritubular fibroblasts which promotes RBC production

-activation of vitamin D

-gluconeogenesis

-metabolism of insulin, steroids, and xenobiotics

What are the metabolic functions that the kidney preforms?

reduced

Patients with diabetes and CKD have ____________ requirements for exogenous insulin.

activated vitamin D3 (calcitriol) supplements

Patients with CKD may require what type of supplement?

Triol

What is the active form of Vitamin D?

0.5-1.5 mL/kg/hr (about 2.7 L/day)

What is the normal urine output?

6 hours

An adult human should be urinating at least every _____________.

Oliguria

-decreased urine output

- <500 mL/day in adults

Anuria

-no or minimal urine output

- <50 mL/day in adults

Polyuria

>3 L/day in adults

-urine output

-glucose

-albumin

-creatinine

-specific gravity

-nitrite, leukocyte, esterase

What does a urinalysis include?

prerenal, intrinsic, or postrenal causes

If the urine output is not normal what can it be due to?

the patient's BG exceeds maximum for reabsorption

If glucose is present in the urine, what does that mean?

kidney damage

If albumin is > 30 mg/g (albuminuria) then what should you suspect?

kidney function

Creatinine is a principle marker of _______________.

indicates presence of solutes in the urine

What does a higher specific gravity mean?

UTI

If nitrite, leukocyte, and esterase is present in the urine what should you think the patient has?

glucosuria

glucose in the urine

urea-splitting bacteria

The normal pH is 4.5-7.8. If the pH is elevated that may suggest what?

glucose

not usually present in the urine because it is reabsorbed at the glomerulus

ketones

acetoacetate and acetone are not normally found in the urine, but are excreted in patients with DKA or under conditions of fasting or starvation

nitrite

not usually present in the urine and it is the result of conversion from urinary nitrite by bacteria in the urine and suggests UTI

leukocyte esterase

not usually present in the urine and it is release from lysed granulocytes in the urine and suggests UTI

heme

hemoglobin and myoglobin are not usually present in urine

red cell hemolysis and rhadomyolysis

A positive heme test without the presence of RBCs suggests what?

significant risk factor for worsening CKD and death

What does a positive heme test in patient with CKD suggest?

charge and size selectivity

Most plasma proteins do not cross the glomerular-capillary membrane due to what?

Albumin

normal: < 30 mg/day

-66 kDa

500-2000 mg/day

normal creatinine:

urine albumin to creatinine ratio

uACR

specific gravity

a measure of urine weight relative to water (1.00) that is preformed using a refractometer to evaluate urine-concentrating ability and hydration status

osmolality

measures the number of solute particles in the urine, is a more accurate measure of the kidney's ability to make a concentrated urine

microscopic analysis

formed elements that may be detected in the urine include erythrocytes and leukocytes, and crystals which aids in differential diagnosis

hematuria

is defined as more than 3 RBCs per high power feild, and the presence of dysmorphic RBCs suggest glomerular etiology

infection or inflammatory conditions (interstitial nephritis)

What does WBCs present in the urine suggest?

kidney dysfunction

Elevated BUN indicates ___________

kidney dysfunction

Elevated SCr indicates _______________

cystatin C

marker of kidney function that is not affected by muscle mass