Urinary System Flashcards by Athea Ordis

This is the major excretory system of the body. What is this?

Urinary System

Note: Some organs in other systems also eliminate waste but cannot compensate for kidney failure.

Walang makakapantay sa function ng kidney.

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FAMILIARIZE ONLY!

What are the Functions of Urinary System?

Excretion
Regulation of blood volume and blood pressure
Regulation of blood solute concentration
Regulation of extracellular fluid pH
Regulation of red blood cells synthesis
Regulation of Vitamin D synthesis

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What is the normal pH level?

7.35 - 7.45

Acidosis - below 7.35
Alkalosis - higher than 7.45

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What are the Components of the Urinary System?

2 kidneys
2 ureters
1 Urinary Bladder
1 Urethra

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These are organs located behind the peritoneum, the membrane that lines the abdominal cavity.

Being bilateral, they are found on both the right and left sides of the body.

Bilateral retroperitoneal organs

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These are vital bean-shaped organs of the urinary system responsible for filtering blood, removing waste products, and maintaining fluid and electrolyte balance.

It weighs 5 ounces and is like a bar of soap or size of a fist

Located between 12th thoracic and 3rd lumbar vertebra.

Kidney

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It is a thin, tough, fibrous layer that forms the outermost covering of the kidney. It serves as a protective barrier and helps maintain the kidney’s structural integrity.

Renal capsule

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The _____ of the kidney is a concave, slit-like structure on the medial side of each kidney where various structures enter and exit. It serves as the gateway to the kidney, providing access for essential vessels, nerves, and ducts.

Hilum

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This is a cavity within the kidney that contains structures such as blood vessels, lymphatics, nerves, and the collecting system.

Renal sinus

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This is the outermost layer of the kidney that surrounds the renal medulla and lies beneath the renal capsule.

Renal cortex

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This is the inner region of the kidney, located beneath the cortex.

Renal medulla

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This is a cone-shaped structure located within the renal medulla of the kidney.

Renal pyramid

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This is the tip of pyramids and these are structures within the renal sinus that collect urine from the renal pyramids.

Calyx or calyces (plural for calyx)

Note: It has Minor and Major.

Calyx: Collects urine from pyramids (minor calyx) and directs it to the renal pelvis (major calyx).

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This is the funnel-shaped structure in the kidney that collects urine from the major calyces.

Renal pelvis

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This is the structural and functional unit of the kidney, responsible for filtering blood and forming urine.

Nephron

Note: Each kidney contains about 1 to 1.5 million nephrons, which work together to maintain fluid balance, remove waste, and regulate electrolytes.

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There are 2 Types of Nephrons in the kidney. What are these?

Juxtamedullary Nephrons and Cortical Nephrons

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This is the nephrons that extend deep into the renal medulla (inner).

Juxtamedullary

Note: Approximately 15% are juxtamedullary

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This is the nephrons that is located mostly in the renal cortex (outer).

Cortical

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The nephron, the functional unit of the kidney, is composed of two main components, each playing a specific role in filtering blood and forming urine.

Renal corpuscle and the Renal tubule

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This is the starting point of the nephron, where blood filtration occurs.

Renal corpuscle

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The Renal corpuscle is consist of two. What are these?

Glomerulus
Bowman’s Capsule

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It is a tuft of capillaries located within the renal corpuscle of the nephron. It is the primary site for blood filtration.

Glomerulus

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It is a cup-shaped structure that encloses the glomerulus and collects the filtrate from it.

The enlarged end of nephron.
Opens into the proximal tubule.
Contains podocytes (specialized cells).
Around glomerular capillaries.

Bowman’s capsule

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It is a thin barrier in the renal corpuscle that separates blood in the glomerulus from the filtrate in the Bowman’s capsule. It allows certain substances to pass while preventing the movement of larger molecules like proteins and blood cells.

Filtration membrane

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It is the fluid that is filtered from the blood through the filtration membrane into the Bowman’s capsule.

Filtrate

The renal tubule is composed of 4. What are these?

* Proximal Convoluted Tubule (PCT) * Loop of Henle (Descending and Ascending limbs) * Distal Convoluted Tubule (DCT) * Collecting Duct

This is the first segment of the renal tubule that processes filtrate after it leaves the Bowman’s capsule. This is **where filtrate passes first**.

Proximal tubule

This is a **U-shaped** structure that concentrates the filtrate by reabsorbing water and salts. Contains descending and ascending loops.

**Loop of Henle** * Descending Loop of Henle: Permeable to water, reabsorbs water into the surrounding interstitial fluid. * Ascending Loop of Henle: Impermeable to water, reabsorbs sodium and chloride.

This is the last segment of the renal tubule before the filtrate enters the **collecting duct**.

**Distal tubule** Note: This is between the Loop of Henle and collecting duct.

This receives filtrate from multiple nephrons and plays a key role in water balance and urine concentration. * Empties into calyces. * Carry fluid from cortex through medulla.

Collecting duct

What is the **flow of filtrate through nephron**?

**Renal Corpuscle** → **Proximal Tubule** → **Descending Loop of Henle** → **Ascending Loop of Henle** → **Distal Tubule** → **Collecting Duct** → **Papillary Duct** Note: This pathway allows for efficient filtration, reabsorption, and secretion, leading to the production of urine that maintains the body’s fluid and electrolyte balance.

Urine formation involves **three main processes**. These processes occur sequentially in the nephron to maintain the body's fluid, electrolyte, and acid-base balance. What are these?

* Filtration * Reabsorption * Secretion

This is where blood is filtered in the **renal corpuscle**, forming a filtrate containing water, ions, glucose, and waste products.

Filtration

It involves **removing substances** from the filtrate and placing back into the blood. This is where nutrients, water, and essential ions are reabsorbed from the filtrate back into the bloodstream.

Reabsorption

It involves **taking substances from the blood** at a nephron area other than the renal corpuscle and putting back into the nephron tubule. Additional waste products and ions are actively secreted from the blood into the filtrate.

Secretion

How many percent of plasma becomes filtrate in Urine Formation - Filtration?

19%

How many Liters of filtrate are produced by the nephrons each day?

180 Liters

1% of filtrate (1.8 Liters) become urine rest is ________.

**reabsorbed** Note: 99% is reabsorbed

What kind of transport does **Proximal tubule** uses for reabsorption of the filtrate?

Active transport

What kind of transport does **Loop of Henle** uses for reabsorption of the filtrate?

Passive transport

What kind of transport does **Distal tubule** uses for reabsorption of the filtrate?

Active transport

What kind of transport does **Collecting duct** uses for reabsorption of the filtrate?

Active transport

This is the active process by which the nephron transfers additional substances from the blood into the filtrate, helping fine-tune the composition of urine and maintain homeostasis.

Secretion

Ammonia comes from ______.

**Nitrogen** Note: Nitrogen comes from protein

Ammonia secretion is ______.

passive

The secretion of Hydrogen (H+), Potassium (K+), creatinine, histamine, and penicillin is by ________.

**Active transport** Note: These substances are actively transported into the nephron.

The secretion of Hydrogen (H+) plays an important role in regulating the body fluid _______.

Ammonia (NH₃) is produced as a toxic byproduct of protein metabolism, specifically during the breakdown of amino acids in the liver. Ammonia is converted to ______ as it is less toxic and more water-soluble than ammonia, making it safer for transport in the blood.

**Urea** Note: Ammonia → Urea → Urine

Creatine is synthesized in the liver and kidneys and **stored in muscles**, where it is used as a quick energy source during high-intensity activities (via creatine phosphate). As muscles use creatine for energy, it spontaneously degrades into ________, a waste product.

**Creatinine** Note: Creatine → Creatinine → Urine

In Assessing Kidney Function in a Person with Kidney Problems, we have **2 Methods**. What are these?

A. Blood Urea Nitrogen (BUN) B. Creatinine (More Sensitive Test)

What is the difference between **BUN** and **Creatinine**?

* **BUN** is a general indicator of kidney function but **less specific** due to potential influences from diet, hydration, or liver function. * **Creatinine** provides a **more accurate and sensitive** measure of kidney health and is commonly used to assess chronic kidney disease (CKD) or acute kidney injury (AKI).

What are the **Three major hormonal mechanisms** that are involved in regulating urine concentration and volume?

* Renin-angiotensin-aldosterone * Anti-diuretic hormone (ADH) * Atrial natriuretic hormone

This is a mechanism for **vasoconstriction**, **increases blood pressure** and conserves sodium and water.

**Renin-angiotensin-aldosterone**

This is a mechanism to **conserve water** to maintain hydration and increase blood pressure. Concentration also of urine.

Antidiuretic hormone (ADH)

Secreted by the **atria of the heart (Right Atrium)** in response to high blood pressure or increased blood volume (stretching of the atrial walls). Increases the excretion of sodium (natriuresis) and water by the kidneys, decreasing blood volume.

Atrial Natriuretic Hormone (ANH)

To Summarize the mechanisms, What will happen if the ff are high? * Aldosterone = _____ * ADH = _______ * ANH = __________

* Aldosterone = concentrated urine * ADH = concentrated urine * ANH = diluted urine

Two narrow, muscular tubes (25–30 cm long) that **connect the kidneys to the urinary bladder**.

Ureters

This is located in the **hypogastric region** which stores urine and can hold a few ml to a maximum of 1000 milliliters.

**Urinary bladder** Note: This is the common site of **UTI** caused by bacteria. It is more common to women because of short urethra and poor cleaning practice.

Remember to specify bladder because we have 2 of it. What are these?

* **Urinary bladder** - hold urine * **Gallbladder** - hold bile

This is the **exit point of urine** as it carries urine from urinary bladder to outside of the body.

**Urethra** Note: Causes UTI in women because it is shorter that makes them more prone to it.

Remember that **Urine is _____**. It is a waste product but it is free from microorganisms..

**Sterile** Note: When it is outside the body then that's when it will be contaminated by microorganisms.

What type of epithelium is the urinary bladder? This is the reason why it holds a maximum of urine and it causes the bladder to expand and change shape.

Transitional epithelium

This is a process that controls the emptying of the bladder. It is activated by stretch of urinary bladder wall that stimulates sensory neurons to inform the person's brain that they need to urinate. Basically a **voiding reflex (urge to urinate)**.

**Micturition reflex** Note: Parasympathetic action potentials cause bladder to contract.

* 50 - 60% Water in the body * 40 - 50% Solid By this, we know that our body is made up of ________.

Fuids

We have **2 body fluid compartments**. What are these?

* Intracellular fluid compartments * Extracellular fluid compartments

This is the body fluids found **inside** the cell. This is approximately **2/3** of all the water in the body (majority).

Intracellular fluid (ICF)

This is the fluids found **outside** the cell.

Extracellular fluid (ECF)

The Extracellular Fluid (ECF) has **3 subdivisions** and it corresponds where they are found in the body. What are these?

**Intravascular Fluid (Plasma)** * The liquid portion of blood. **Lymph fluid** * lymph **Interstitial fluid** * Found between cells (in the tissue spaces). * In between that causes edema or pamamaga

Intracellular fluid are composed of **ions or electrolytes**. What are these?

* Potassium * Magnesium * Phosphate * Sulfate

Positively charged ions are called ______.

Cations

Negatively charged ions are called ________.

Anions

What components or electrolytes can be found **outside the cell**?

* Sodium (Na) * Calcium (Ca) * Chloride (Cl) * Bicarbonate (HCO3)

**No change** in cell shape.

Isotonic

This is when more water is outside the cell and causes **cell swelling**.

Hypotonic

This is the shrinking or crenation of cells.

Hypertonic

This is **controlled by the thirst center** located in the hypothalamus. This is about the concentration of ions, particularly, If Sodium is high then you will be dehydrated and the urge to drink will happen.

Thirst regulation

What is the **thirst-center** of our body?

Hypothalamus

These are the **dominant or most abundant ions** in the Extracellular Fluid. This is about the action potention or nerve stimulation. This is secreted through sweat but majority is excreted in urine.

**Sodium Ions** Note: Wherever there is sodium, water follows. Kaya pag kumain tayo ng maalat, nauuhaw tayo after.

This is the **most important to monitor**. It is for muscle contraction, specifically, for cardiac muscle contraction. The concentration of this ion needs to be maintained within a narrow range as increase or decrease of it can lead to heart problems (CARDIAC ARREST!).

**Potassium Ions** Note: 90% excreted in urine and 10% excreted with feces

This is ions for **bones, muscle contraction, and cardiac muscle**. It is increased with Parathyroid hormone and decreased with Calcitonin.

Calcium Ions

This is **second next abundant to sodium**. Hydrogen + Chloride = Hydrochloric Acid. So this is acid.

Chloride

These are **minor substances only**. Not much important but it is about Acids being removed in kidneys through urination.

Phosphate and Sulfate Ions

The body maintains a normal blood pH of 7.35–7.45 to support enzymatic activity and metabolic processes. This balance is achieved through three main mechanisms. what are these?

* Buffers * Respiratory System * Kidney

What is the normal pH range of the blood?

7.35 - 7.45

This is the **weakest and slowest** in correcting base balance. It can neutralize **weak acids or bases** only. Chemical systems that resist changes in pH by binding or releasing **hydrogen** ions (H⁺).

Buffers

There are **3 classes of buffers**. What are these?

* Proteins * Phosphate buffer * Bicarbonate buffer

This is the **fastest (minutes)** as it regulates blood pH by controlling the level of **carbon dioxide** (CO₂), which is in equilibrium with carbonic acid (H₂CO₃).

**Respiratory System** Removing H2CO3 (Carbonic Acid) → (CO2 + H2O) → Release in breath

This is the **second fastest**. Maintain pH by excreting **H⁺** and reabsorbing **bicarbonate** (HCO₃⁻). It takes hours to days for it to correct base balance.

Kidney

This is when the pH level of blood is **below 7.35**. When the blood has too much acid or too little base, causing a decrease in blood pH.

Acidosis

This is when pH level of blood is **above 7.45**. When the blood has too much base or too little acid, causing an increase in blood pH.

Alkalosis

There are two types of alkalosis based upon the cause. What are these?

**Respiratory** (lung problem) and **Metabolic** (kidney problem) Note: This is the origin of problem in pH level of blood like **Respiratory Acidosis and Respiratory Alkalosis** & **Metabolic Acidosis and Metabolic Alkalosis**