Urinary System

What is the most important organ of the urinary system?

The Kidneys

What two organs receive 25 percent of the cardiac output in your body?

The kidneys

Major excretory organs of the urinary system?

Kidneys

What does the urinary system do?

Produce Urine (fluid containing water, ions, and small soluble substances.

The kidneys are closely next to which organ but only separated by the renal artieres?

The Aorta

Receives a quarter of your blood at such high pressure that capillaries are extremely distended and have a unique design

Kidneys

Rest of the organs belong to the urinary tract except the

kidneys, which filter blood and produce urine.

Urinary tract

Transport or Store newly made urine from the kidneys (the factory) to the outside

How many ureters do you have?

Two

Ureters

receive urine from the kidneys

How do ureters receive urine from the kidneys?

Conduct urine to the urinary bladder by gravity and peristalsis

Urinary bladder

receives and stores urine

Which part of the urinary tract contracts its muscle walls to allow the elimination of urine to the urethra?

The urinary bladder

Urethra

Organ in charge of conducting urine outside of the body

Proper order of the urinary tract

Ureters —> Urinary bladder —> Urethra

Functions of the urinary system

Adjusting the blood volume and blood pressure, stabilize pH, remove toxins and drugs in blood stream, conserve nutrients by preventing their loss in urine, and regulating blood plasms concentration of sodium, potassium, chloride, and other ions

element or chemical that contributes to blood volume and blood pressure of the urinary bladder for the kidneys?

RAAS

Renin, Angiotensin, and aldosterone system - increases sodium and water retention to regulate blood volume and pressure.

Organ and hormone that helps conserve water by acting on our kidneys?

Posterior Pituitary gland - releases ADH (Antidiuretic hormone) targets the kidneys to promote water reabsorption in the kidneys, reducing urine output.

What hormones help conserve sodium and water while eliminating potassium?

Angiotensin and aldosteron

What hormone helps us conserve water to elevate blood volume and pressure?

ADH (Antidiuretic hormone)

One of the biggest functions of the kidneys are

Blood volume and blood pressure

Blood pressure and volume

Used as a target for the actions of several hormones regulating blood, plasma concentrations of sodium, potassium chloride, and other ions like calcium (Ca2+)

PTH

Stimulates the kidneys to conserve calcium and synthesize calcitriol

Calcitriol

Increases absorption of calcium in the intestinal mucosa

What is the number one regulator of calcium in the body?

PTH (parathyroid hormone)

Intercalated cells

specialized cells of the kidneys that are responsible for regulating the pH composition of our blood and body fluids

What are the intercalated cells called

Type A and Type B

How do intercalated cells regulate the pH composition of our blood and body fluids?

By eliminating hydrogen ions when suffering from an acidosis and reserve bicarbonate OR having alkalosis by eliminating bicarbonate and observing hydrogen

Glucose and proteins

The number one thing that must be reabsorbed by the kidneys during the filtration process, ensuring they are not lost in urine.

What should we find ZERO in our urine?

glucose and proteins

Hyperglycemia or a diabetic patient

may have high concentrations of glucose in the blood

If you are not using glucose as an energy source and instead of fatty acids this could cause

Hyperglycemia to get rid of excess glucose OR cause excess ketone bodies leading to diabetic ketoacidosis.

Fibrous capsule

Very thin line (outer layer) surrounding the kidneys that provides protection and structural support.

Renal cortex

The outer layer of the kidney after corpuscle, containing the renal corpuscles and renal tubules. It plays a crucial role in filtering blood and producing urine. Where the majority of the urine making structures called nephrons

Where do nephrons reside in?

The renal cortex of the kidneys

Renal medulla

has triangularly shaped pyramids with columns between them

Renal columns

Used for blood vessels that come in from the renal artery to make their way into the surface of the kidney.

Renal pyramid

A cone-shaped structure in the renal medulla that contains nephrons, which are essential for urine formation.

Tubules —> collecting duct bring urine

Renal papilla

Tip of the renal pyramid that make contact with the papillary ducts from the collecting duct where urine drains into the minor calyx.

Calyx(s)

Empty space or open structures of the kidney that receive urine from the renal papilla and funnel it into the renal pelvis.

Minor Calyx

Small cup-like structure in the kidney that collects urine from the renal papilla in a single kidney lobe and channels it to the major calyx.

Major Calyx

Larger cup-like structure that collects urine from multiple minor calyces and funnels it into the renal pelvis.

Renal Pelvis

Large funnel-shaped structure that collects urine from the major calyx and passes it to the ureter.

Where are kidney stones most commonly formed in?

spaces within the minor and major calyxes

What is the flow of urine from the collecting duct to the ureter

collecting duct, to the renal pelvis, passes through the minor calyx, major calyx, and flows into the ureter.

How many types of nephrons are there?

Two

85% of cortical nephrons are mostly located where?

in the renal cortex

Cortical nephrons

Important for the formation of regular urine

15% of juxtamedullary nephrons are located where?

between the renal cortex and the renal medulla (next to)

Juxtamedullary nephrons

Contain a long nephron loop that plays a crucial role of concentrated urine

What nephrons work together with ADH to form a concentrated urine when we are dehydrated?

Juxtamedullary nephrons

What lets us form dark concentrated urine when we cannot afford to lose a lot of water?

The long nephron loop and collecting ducts of juxtamedullary nephrons, which are influenced by antidiuretic hormone (ADH).

How many nephrons in each of our kidneys?

1.2 million

Two main areas of the nephrons?

The renal corpuscle and renal tubule.

Renal Corpuscle

glomerular capillaries and glomerular (Bowman) capsule

Renal tubule

Continuation of the nephron with many turns called convoluted tubules

How many convoluted tubules are there in the renal tubule?

Two, Proximal and Distal convoluted tubule

Proper order of a nephron

Afferent and efferent arteriole —> renal corpuscle (glomerular capsule & the glomerulus) —> proximal convoluted tubule —> loop of Henle (Ascending & Descending limb) —> distal convoluted tubule —> collecting duct —> Papillary duct

Glomerular capsule

Also known as Bowman’s capsule and part of the renal corpuscle that surrounds the glomerulus, cup shaped chamber.

Proximal convoluted tubule (PCT)

The first segment of the renal tubule responsible for most of reabsorbing (highest concentration) nutrients, electrolytes, glucose, sodium water filtered from the blood. contains microvilli

What is considered the jejunum of the nephron?

The proximal convoluted tubule (PCT) as it is primarily responsible for nutrient reabsorption.

Nephron loop

Contains a thick and a thin limb, each limb contains a thin and thick segment

In the descending limb you can only

reabsorb water

In the ascending limb you can only

reabsorb sodium and chloride (aka salt)

Distal convoluted tubule

Where PTH, aldosterone, ADH start acting to regulate or adjusts tubular fluid composition by reabsorption and secretion

Function of aldosterone?

reabsorbs sodium into the body in exchange for potassium secretion

How does the flow of the blood work in the beginning of the nephron?

Blood goes into the afferent arteriole first, filters blood, then most will leave through the efferent arterioles, the rest after will go through the proximal convoluted tubule

Collecting system

Pathway of tubes carrying tubular fluid collecting from different nephrons

Collecting duct has two main types of cells called

Intercalated cells and Principal cells

Principal cells

Target for aldosterone which conserves water and sodium and secrete potassium, responsive to ADH and intercalated cells