Homeostasis

Question 0

What are glomeruli?

Answer 0

The capillaries derived from the branching, afferent arterioles. Once blood passes through a glomerulus, it is then transported via efferent arterioles away from it to the vasa recta

Question 1

What is the functional unit of the kidneys?

Answer 1

The nephron

Question 2

What is the anatomy of a nephron, in order?

Answer 2

The glomerulus is surrounded by the Bowman’s capsule, which leads into the proximal convoluted tubule, which leads us to the descending and ascending loops of henle, which brings us to the distal convoluted tubule, which then leads to the collecting duct.

Question 3

Filtration is…

Answer 3

The first step of osmoregulation and occurs as blood moves from the glomerulus into Bowman’s space. Proteins and cells bigger than the glomerular pores will NOT BE FILTERED. It will stay in the blood, which is then transported to the efferent arterioles into the vasa recta.

Question 4

Is the filtrate iso/hypo/hypertonic to blood?

Answer 4

Isotonic-so that neither the capillaries or the capsule swells.

Question 5

Secretion is…

Answer 5

The process used by the kidneys to get rid of ions or other substances (salts, acids, bases, urea) that are present in excess in the blood. Also a mechanism for excreting wastes that are too big to be filtered through the glomerulus.

Question 6

Reabsorption is…

Answer 6

The process by which compounds that are filtered and/or secreted are taken back up for use (ie: glucose and amino acids.

Question 7

Excretion occurs when…

Answer 7

The filtrate fails to leave the tubule and be reabsorbed.

Question 8

Where does reabsorption occur?

Answer 8

In the proximal and distal tubules. The ascending and descending loops of henle and the collecting duct can, but are more selective!

Question 9

The descending loop of henle is permeable to:

Answer 9

Water

Question 10

The ascending loop of henle is permeable to…

Answer 10

Salt

Question 11

The collecting duct variably reabsorbs…

Answer 11

Water!

Question 12

How does the permeability of the collecting duct change according to hydration?

Answer 12

1) if you are plenty hydrated, permeability to both salt and water decreases, and we will see increased excretion and more diluted urine.
2) if you are dehydrated, permeability to salt and water increases, allowing for increased water reabsorption and a more concentrated urine output.

Question 13

ADH/Aldosterone act to…

Answer 13

Increase the permeability of the collecting duct➡️increased water reabsorption

Question 14

What is reabsorbed in the proximal convoluted tubule?

Answer 14

Glucose, AA, soluble vitamins, water, and most salts

Question 15

The descending loop of henle is Iso/hypo/hypertonic to the surrounding interstitium?

Answer 15

Hypertonic-there is more water in the filtrate than in the tissue, driving water out of the tubule to the tissues.

Question 16

The ascending loop of henle is Iso/hypo/hypertonic to the surrounding interstitium?

Answer 16

Hypotonic-salts are actively pumped out of the filtrate into the tissues to make the gradient isotonic.

Question 17

Aldosterone is…

Answer 17

A steroid hormone released by the adrenal cortex in response to low blood volume (and thus, low blood pressure). Works to make the collecting duct more permeable to sodium (and therefore, water too), which ultimately increases blood volume and blood pressure, and increase potassium excretion.

*USE A DRUG THAT BLOCKS ALDOSTERONE ACTIVITY IN PEOPLE WITH HYPERTENSION (HIGH BP), because less aldosterone means less sodium and water, which means less blood volume and a lower BP!

Question 18

ADH (vasopressin) is…

Answer 18

A peptide hormone that increases the collecting ducts permeability to water by making the cell junctions leaky. It is made in the hypothalamus, stored in the posterior pituitary, and secreted in response to high blood osmolarity (which means there is more solute than water in the blood). This causes increased water reabsorption, resulting in more concentrated urine and a lower blood osmolarity.

Question 19

A diuretic functions so that..

Answer 19

It decreases water reabsorption, making the body excrete more dilute urine, thereby “dehydrating” the interstitium. So a diuretic (like coffee and alcohol) will make you pee more but also leave your body dehydrated, as it INHIBITS the activity of ADH.

Question 20

What are the 3 compounds that should always be absent from healthy urine?

Answer 20

Blood, protein, and glucose. (Blood is too large to filter, and the other 2 should be fully reabsorbed).

Question 21

The hepatic portal vein…

Answer 21

Delivers nutrients absorbed during digestion to the liver.

Question 22

The liver produces…

Answer 22

Bile, which solubilizes fats and aids in their absorption.

Question 23

The liver assists with blood glucose regulation by:

Answer 23

In times of plenty, glucose is conveyed to glycogen (a polymerized stored form) and in times of famine, glycogen is converted back to glucose and released into the blood stream. Can also create glucose via gluconeogenisis.

Question 24

How does the liver prevent ammonia build up?

Answer 24

Regulating the nitrogenous waste products. The liver combines amino groups with CO2 to create urea which is to be excreted.

Question 25

What are all the functions of the liver?

Answer 25

1. Produce bile
2. Glucose regulation
3. Nitrogenous waste regulation
4. Detoxification
5. Stores vitamins and cofactors
6. Destroys old RBCs
7. Synthesis of blood proteins
8. Defense against antigens
9. Beta-OX of fatty acids to ketones
10. Intercom version if carbs, fats, and AA