UnitD - Nephrons and formation of urine

What is the part of the kidney that filters the blood?

The nephrons, about a million in each kidney

What is the nephron composed of(6)?

1. Glomerulus

2. Bowman’s capsule

3. Proximal tubule

4. Loop of Henle

5. Distal tubule

6. Collecting duct

What is the efferent arteriole?

The arteriole that’ll become the capillary wrapping around the nephron

What are the 4 process of the formation of pee?

1. Filtration

2. Reabsorption

3. Secretion

4. Excretion

Where does filtration occur in nephron?

The glomerulus into the bowman’s capsule

Is the glomerulus under high or low pressure?

High pressure

What is forced/filtered into the glomerulus and into the bowman’s capsule?

Water and dissolved solutions, ex)NaCl, glucose, amino acids, vitamins, urea, uric acid, etc

What cannot cross the glomerulus → bowman’s capsule and why?

Blood cells, platelets, and proteins because they’re too big

Where is reabsorption happening and what is the process?

From the nephron tubules → blood through the process of passive transport in the proximal tubule

What happens to the majority of the filtrate?

It is selectively reabsorbed

What filtrates get reabsorbed(5)?

1. Water

2. glucose(100% reabsorbed)

3. amino acids(100% reabsorbed)

4. NaCL

5. K, H, HCO3 to balance pH

What helps maintain H2O balance?

Loop of Henle “dipping” into the “salty” medulla

What are the 2 hormones that increase the reabsorption of H2O back into your blood?

1. Antidiuretic hormone(ADH)

2. Aldosterone

What does ADH respond to and how does it respond?

Responds to dehydration, then tells the distal tubules and collecting ducts to reabsorb more water

Where is ADH made?

In the Hypothalamus

Why is diuretics bad for ADH?

Diuretics like caffeine block the action of ADH

What does aldosterone respond to and how does it respond?

Responds to low blood pressure and tells the distal tubules to actively transport Na+ back into the blood, then H2O follows by osmosis

Where is aldosterone made?

In the adrenal glands, “hats” on the kidneys

What happened to the urine when your excretory systems repsponds to ADH or aldosterone?

Urine becomes more concentrated making it darker

Where does secretion occur?

From the blood → tubules

What happens in secretion and how is it transported?

More movement of waste from the blood back into the nephron, through active transportation

What makes up your urine(3)?

1. ~95% urea

2. ~2.5% uric acid

3. Remaining as uric acid, excess minerals, etc