4.1 Human Body Systems

Urinalysis

A test that determines the contents of urine

What can a urinalysis be used to detect?

Some types of disease, particularly in the case of metabolic disorders and kidney disease

What are the main roles of the kidney?

• Removing waste products from the blood

• Leaving nutrients such as proteins and glucose in the blood

• Maintaining the acid base balance

• Regulating water and electrolyte balance

What are the components of a urinalysis?

• Macroscopic examination

• Chemical analysis

• Microscopic examination

What physical properties are you looking for during a urinalysis?

Color & clarity

What is being looked for in terms of color during a urinalysis?

• Normal urine is a straw to amber color

• Abnormal urine can be colorless, dark yellow, orange, pink, red, green, brown, or black

What is being looked for in terms of clarity during a urinalysis?

• Normal urine is clear

• Abnormal urine can be hazy, cloudy, or turbid

What are the chemical properties of urine?

Specific gravity, pH, protein content, glucose content, and ketone content

What are urine strips used to detect?

The chemical properties of urine

Parts of a chemical analysis: pH

• Measures if urine is acidic, basic, or neutral

• Normal urine ranges from 4.6-8

Parts of a chemical analysis: specific gravity

• Measures the concentration of particles in the urine & evaluates the body’s water balance

• The more concentrated the urine, the higher the urine specific gravity

• The most common increase in urine specific gravity is the result of dehydration

• Normal urine ranges from 1.002 to 1.028

Parts of a chemical analysis: ketones

• Measures the presence of or absence of ketones in urine

• Normal urine does not contain ketones

What are ketones?

The endpoint of rapid or excessive fat breakdown

Parts of a chemical analysis: proteins

• Normal urine levels of proteins are very small, about 0 to 8 mg/dl

Parts of a chemical analysis: glucose

• Measures the amount of sugar in a urine sample

• Normal urine does not contain glucose

What elements may be seen in a microscopic examination of urine?

• Red blood cells (not found in normal urine)

• White blood cells (not found in normal urine)

• Epithelial cells (found in normal urine)

• Crystals (small amounts found in normal urine)

• Bacteria

What is the role of epithelial cells in the urinary system?

They line the urinary tract

What are examples of common crystals?

Calcium oxalate, triple phosphate, and amorphous phosphate

What does a large number of crystals indicate?

Either kidney stones are present or there is a problem with how the body is using food

What structures are permeable to water?

The collecting duct and descending loop (the ascending loop is permeable to sodium, but not water)

What structures primarily assist in filtration?

The glomerulus and Bowman’s capsule

What structures primarily assist in reabsorption?

Primarily the proximal convoluted tubules (many others assist)

What structures primarily assist in secretion?

The distal convoluted tubules and the collecting ducts

What does the urinary system control?

The production of urine, getting rid of waste, and water levels

What is the correlation between water in the body and blood pressure?

As water levels rise, pressure rises

What do the kidneys do concerning blood pressure?

They maintain osmolarity and get rid of excess solutes to lower your blood pressure

What substances can’t come out of capillaries?

Red blood cells and proteins

What is ADH?

A hormone secreted in the pituitary gland and created in the hypothalamus that recognizes high solutes, regulating blood pressure and solute concentration

What kind of feedback loop is the urinary system?

A negative feedback loop

What does ADH direct the kidneys to do?

To retain water, reducing thirst and the volume of urine produced

Where is urine formed?

In the nephrons

Gestational Diabetes

• Pregnancy hormones cause high blood sugar and insulin resistance

• Symptoms include thirst, lethargy, and weight loss

Proteinurea

• Protein is present in the urine

• There are oftentimes no symptoms

Urinary Tract Infection (UTI)

• Infection/inflammation causing white blood cells and crystals in the urine

• Symptoms include peeing frequently, burning sensation when peeing, lower back pain, and a low-grade fever

Anorexia Nervosa

• Ketoacidosis is developed (fat is broken down for fuel, creating ketones)

• Symptoms include low energy, losing hair, and losing period

Central Diabetes Insipidus

• Deficiency of ADH, making the kidneys unable to conserve water

• Symptoms include constant thirst, trouble sleeping, and family history of pituitary problems

Kidney Disease/Failure

• Blood is not properly filtered and ends up being found in the urine

• Symptoms include lethargy, dizziness, trouble sleeping, swollen feet, ankles, and face, back pain, and dark urine

What type of tissue is the bladder?

Transition epithelium, allowing for a change in shape of the bladder

What shape is the bladder when it is empty?

Cubodial

What shape is the bladder when it is full?

Squamous

What are the processes where food and drinks are converted to waste products?

Digestion and filtration

Filtrate

A liquid which has passed through a filter

Glomerulus

• Cluster of capillaries inside of the Bowman’s capsule where blood filtration begins

• Pressure is extremely high when first entering from the artery, causing water and other products to be diffused out

Proximal Convoluted Tubule

Reabsorbs nutrients from the filtrate

Loop of Henle

Helps with urine concentration

Distal Convoluted Tubule

Connects the Loop of Henle to the collecting duct, helping with final adjustments to the filtrate

Collecting Duct

Runs vertically through the medulla of the kidney, receiving fluid from many nephrons and directing it toward the renal pelvis

Label the image

1. Efferent arteriole

2. Afferent arteriole

3. Glomerulus

4. Bowman’s capsule

Efferent Vessel

• Exits

• Carried filtered blood away from the nephron

Afferent Vessel

• Arrives

• Brings unfiltered blood to the nephron

Bowman’s Capsule

Collects the fluid filtered out of the blood and is continued towards the proximal convoluted tubules

Tubular Reabsorption

As the filtrate moves towards the tubules, necessary substances are reabsorbed from the tubules into the surrounding capillaries

Explain the whole process of the nephron

1. The renal artery dumps large volumes of blood into capillaries of the glomerulus, and the high pressure forces water and solutes out of the blood and into the Bowman’s capsule

2. Filtration occurs where water, ions, glucose, and waste pass while blood cells and proteins are retained in the blood

3. Reabsorption occurs where the filtrate moves through tubules and necessary things like water, glucose, and ions are reabsorbed from the tubules into the surrounding capillaries

4. Capillaries excrete any other waste to the kidney tubules to be excreted as urine

5. The remaining liquid called urine passes into the collecting duct to then be secreted by the body

Tubular Secretion

Waste products that were not initially filtered are secreted from the capillaries into the tubules to be excreted via urine

Glomerular Filtration Rate

Represents how rapidly the body is cleansed of metabolic waste, and the amount of fluid and dissolved substances the kidneys are capable for filtering per minute