Biology 20: Excretory System: Hormones & Regulation, Filtration & Urine Formation, The Nephron Structure & Function, The Urinary Tract & Anatomy and More

What is ADH and what is its role?

Antidiuretic Hormone (ADH) regulates water reabsorption in the nephron by making the tubule more absorptive to water (manages water balance)

What is Aldosterone?

Regulates salt reabsorption in the nephron by making the tubule more absorptive to salt (manages blood pressure)

How is urine formed? (2 Main Stages)

Filtration: Movement of fluid from the blood into the Bowman's capsule.

Reabsorption: Transfer of essential solutes and water from the nephron back into the blood.

What is filtered OUT (filtrate) at the glomerulus (enters the nephron)?

Water, salts, glucose, amino acids, hydrogen ions, and urea.

What stays in the blood (filtered blood) (NOT filtered at the glomerulus)?

Blood plasma proteins, red blood cells, and platelets.

What makes up the filtrate at each section?

Bowman's Capsule: Water, sodium, chlorine, glucose, urea, uric acid.

Proximal Tubule: Water, sodium, chlorine, glucose, urea, uric acid.

Descending LoH: Water

Ascending LoH: Sodium

Distal Tubule: Water, sodium

What is a Nephron

The functional unit of the kidney, remove waste products and solutes from the blood while reabsorbing water

Role of the Glomerulus

A group of capillaries that acts as a filter, allowing only certain substances to pass into the Bowman's capsule

Role of the Bowman's Capsule

A structure that surrounds the glomerulus and collects the filtered fluid (filtrate)

Role of the Afferent vs Efferent Arterioles

Afferent: Supplies the nephron with blood from the renal artery

Efferent: Carries blood away from the glomerulus after it has been filtered

Role of the Proximal Tubule

The thin tubule directly following the Bowman's capsule where the first stages of reabsorption occur

Role of the Loop of Henle

A section of the tubule that descends (H2O) and ascends (NaCl) for further processing of the filtrate

Role of the Collecting Duct

Gathers urine from many nephrons and merges in the renal pelvis

Role of the Distal Tubule

H2O and NaCl are reabsorbed with the help of ADH and Aldosterone.

Role of the Peritubular Capillaries

A network of vessels where reabsorbed water and essential solutes from the nephron are transferred back into the blood

What are the main components of the urinary tract

The bladder, kidneys, ureters, and urethra

What is the role of the Kidneys

They filter wastes and excess water from the blood, eliminate toxins, and help maintain pH and water balance in the bloodstream

What is the role of the Ureters

They conduct wastes and excess water (filtrate) from the kidneys to the urinary bladder

What is the role of the Urinary Bladder

It stores urine until it is ready to exit the body; receptors in the brain are activated as it fills

What is the role of the Urethra

It is the tube through which urine eventually exits the body

What helps veins move blood back to the heart?

One-way valves and muscles squeezing your body.

Where is the AV node?

In the lower part of the right atrium.

How does oxygen get from lungs to cells?

It passes from air sacs into blood, sticking to red blood cells.

How does carbon dioxide get from cells to lungs?

It travels through blood from cells to lungs, then is exhaled.

What is the function of smooth muscle?

Found inside organs like intestines.

What is the function of cardiac muscle?

Makes up the heart.

What is the function of skeletal muscle?

Muscles you move, like arms and legs.

How do vaccines work?

They show the immune system a harmless germ version to build immunity.

How are the immune and digestive systems connected?

Stomach acid and gut help kill germs in food.

What happens if enzymes get too hot?

They stop working because heat changes their shape (Denature).

How does the circulatory system help other systems?

It carries oxygen, nutrients, and wastes around the body.