MLS1113 Exam 2

What is actively reabsorbed in the proximal convoluted tubule?

Glucose

What is the major point of pH regulation within the nephron?

Distal convoluted tubule

What is the collection point of filtrate within the nephron?

The glomerular space

Your blood has to remain at a pH level of _________ at all times. Your kidneys are, in part,responsible for this.

7.35-7.45

Your kidneys account for about 0.5% of your total body weight, yet they receive about ____% of the total blood pumped by the heart.

25%

Your kidneys filter about _____ ml of blood per minute, or about 45 gallons per day. That's your total blood volume about 20 times a day!

150 ml blood per min

Basic Functions of the Kidney Generic answer:

Filtration.

Basic kidney functions

1. filtration-strainer for blood, 2. reabsorption- taking nutrients back after 3. filteration, secretion- elimination of toxic waste (excretion)

Why do the kidneys filter the blood in order to perform a number of tasks?

A. Regulation 1. PH 2. concentration of chemicals 3. water and electrolytes balance

B. Detoxification and elimination of wastes Urea, ammonia, salts… (waste products)

C. Erythropoesis: RBC production (EPO-Erythropoietin)

EPO shots

can help with O2 but can have a risk of blood clots

The kidneys are part of the

endocrine system and secrete hormones that stimulate red blood cell production

Normal kidneys

exhibit the shape of a bean and are located in the abdomen but are more towards your back.

Each kidney is about

12.5 cm in length.

Our ureters (one per kidney)

originate from the indented area of the kidney, and are approximately 25 cm.

Each ureter

extends to the apex (base) of the bladder.

From the bladder the urethra (4 cm in women and 24 cm in men)

allows urine to travel to the outside world.

The kidney is divided into two sections

Cortex and Medulla

Cortex Major Function:

entire area lining the kidney, filtration takes place

Medulla Major Function:

inner area of the kidney, collection of filtrate

Renal Pyramids look like

looks like candy corn

Calices (Calyx)

1. Major- palm of the hand 2. Minor- finger like of the palm

Papilla -

Apex (base or bottom) of each pyramid

Renal Pelvis

series of funnels that leads to ureter

What does the nephron do?

Functional unit of the kidney, Site of electrolyte exchange, water reabsorption, waste secretion etc.

Afferent Arteriole

unfiltered blood enters the glomerulus then Branches into the glomerular capillaries. A for Access

Glomerular Capillaries do what

Allows the blood to spread out and be filtered.

Surrounded by a three (tri) layer basement membrane.

determines what comes in and what stays out

The basement membrane is permeable to:

70k daltons or smaller, water, solutes, glucose

The basement membrane glomerular

consists of three layers that allow only certain substances to pass through.

Efferent Arteriole

All substances that are not allowed to pass through the basement membrane return to the circulation via the efferent arteriole. E for Exit

All substances passing through the basement membrane are collectively called _____________.

filtrate

We convert approximately 180,000 ml (180L) of filtrated plasma per day into a urine volume ranging from ____ to _____ ml.

500-1000 ml (0.5-1 L)

Glomerular Space (Was known as the Bowman's capsule/space)

Collection point for glomerular filtrate.

Where is the first point of reabsorption and what is absorbed?

Proximal convoluted tubule

Glucose, amino acids, salts and water. (close to the glomerulus)

Reabsorption: Active

requires energy.... like glucose- renal threshold the limit the kidney can take

Reabsorption Passive

like water

Nephron Loop (Was known as the Loop of Henle) As the filtrate travels down the Loop of Henle the filtrate becomes:

*more concentrated*

As the filtrate travels back up the Loop of Henle, filtrate becomes:

less concentrated, solutes are being taken out

what is the only point in the whole process where water cannot go in or out of the tubules?

Ascending loop of Henle

how does the Distal Convoluted Tubule pH regulation? what pH is normal?

maintains pH for blood 7.35-7.45 by secreting acidic ions and passes through urine

What part of the nephron secretes H+ ions?

The distal convoluted tubule

Secretion:

circulation to filtrate

Collecting Tubule (duct)

Final point of WAter regulation.

What hormone regulated the amount of water in the body?

ADH, Renin, angiotensin, aldesterone

Diurese meaning

discharge of urine

What is urine?

96% water, 4% solutes (Na, K, Cl)

Urine output is based on:

1. intake 2. hormones (ADH)

The process of regulating the amount of urine excreted by the body is controlled by

hormones

What hormone responds to changes in electrolyte concentrations? Blood pressure? Water concentration?

in electrolyte concentrations (aldosterone), blood pressure (angiotensin), water concentrations (ADH) etc.

The key hormones responsible for urine production are:

1.ADH 2. Renin-angiotensin 3. Aldosterone

Urinary Output: Normal urine output is

0.5 liters to 1.5 liters per day.

Anuria:

no urine output or very little drops (kidney stone)

Oliguria:

decreased output

Polyuria

increased output >2500 ml/day

Clean containers:

not dirty, but not sterile

Sterile containers:

free of microorganisms (pathogenics)

Collection Times• Random-

anytime, UA, random protein

Collection Times• First morning-

more concentrated, HCG

Collection Times• Postprandial-

After something... medication or glucose

Collection Times• Fasting, what test would be?

Glucose

Collection • Clean catch midstream

UA

Collection • Timed

24 hour (8am-8am) need VOL

Collection • Catheterized specimens

latex tube into the urethra

Collection • Supra-pubic aspirate

needle through abdomen

Collection • Chain-of-custody collections

drug testing

The best urine sample

is a freshly voided, midstream clean-catch.

Sometimes it is necessary to preserve a sample for further analysis. So you can:

• *Freeze it*- not good with UA but ok for chemical analysis •

*Refrigerate it*- okay for UA but will change pH and formation of crystals but slows down bacterial growth •

*Chemically preserve it*-boric acid powder, expensive

unpreserved urine: Increase:

bacteria growth, crystals, pH

unpreserved urine: Decrease:

cells, ketones, casts, glucose (bacteria uses glucose to stay alive)

Physical Appearance: Color examples

Yellow, dark yellow, light yellow, brown, red, green, orange etc.

Character or clarity

Clear, slightly cloudy, cloudy, turbid, solid etc.

what gives urine Color

1. Urochromes or urobilin -RBC metabolism

2. Some foods and medications give colors to urine

3. Disease states may alter urine color

Normal colors are

colorless, straw, light yellow, yellow, dark yellow (Color varies with urine concentration)

Urine colors Red:

blood, beets, red blood cell breakdown

Urine colors Brown:

Bilirubin, blood

Urine Colors Bright Orange

medication pyridium (AZO), cant do UA with this color

Urine Colors Green

supplements, vitamins,

Urine Colors Pink:

porphyrins- rbc metabolism

Urine Colors Black:

melanin- skin pigment, cancer

Urine Colors Blue:

methylene blue,

Character or Clarity

Report as clear, slightly cloudy, cloudy, or turbid

Nonpathogenic causes for cloudy urine:

refrigeration, improper storage, menstruation

Pathogenic causes for cloudy urine:

dehydration, UTI, casts, cells, infection

Microscopic examination of urine has been performed since

1926.

Microscopic examination of urine is still performed because:

It is an excellent diagnostic tool (cheap, easy, fast)

Automation-Commercial Systems

These systems are often faster, more accurate and as cheap (per test) as manual urinalyses. can examine urine and count WBCs, RBCs, Epis etc.

Why would lab not use an automatic UA machine?

expensive

Generally 10-12ml of sample are spun at a relative centrifugal force of

450 g for 5 minutes.

Why is urine centrfuged at 450 g for 5 minutes?

dont want to damage cells

After Centrifugation-bottom of urine "the stuff"

sediment (formed elements)

After Centrifugation-Liquid portion

supernatent

After Centrifugation-Still contains:

chemicals

urine stain

1. (most common-sedi stain) Supravital stain 2. Gram stain (pos or neg)

Hansel Stain

eosinophil (allergies, inflammation, parasites)

Fat stains: Sudan III

Confirmation for fat in urine

Fat stains: Oil Red O

confirmation for fat in urine

When stuff is hard to see...

1. Clean the objectives and oculars 2. Change your microscope

To report urine elements:

10-15 fields, 10x (40x to idenitify)

Red Blood Cells Appearance:

could be crenated, circles with indent, small, smooth