Renal System

Question 1

What are two sphincters involved in holding and releasing urine?

Answer 1

internal vs external sphincter.

- Internal urinary sphincter is made up of smooth muscle and is involuntary.

Question 2

What are the components or parts of the urinary system?

Answer 2

Kidney - ureter - bladder – interior smooth muscle sphincter – exterior sphincter

Question 3

describe the anatomy of the kidney

Answer 3

ureter – renal pelvis – medulla (nephrons, renal pyramid) – the cortex

Question 4

What are the three processes that produce urine?

Answer 4

• extraction/ filtration: cell plasma are extracted from the bloodstream, but if all of this is released in the urine then we lost all nutrients & we would probably die as well because of the drop in blood pressure.
• -> reabsorption: sugar, amino acids & water.

but what do we do then when we have an excess of stuff in our blood. For example, you take too much vitamin C in the morning, what happened to the excess?

–> Secretion

Question 5

What gets reabsorbed after filtration? hint: what do you need to survive?

Answer 5

• glucose
• Amino acid
  and water

Question 6

What is secreted into urine?

• What are some waste products that just need to get the hell out of your system?
• What are things that are toxic?

Answer 6

• muscle byproduct – creatine
• drugs
• toxins

Question 7

How does the loop of Henle generate the concentration gradient in the medulla?

Answer 7

• Active ion transport in the upper part of the ascending limp
• Aquaporins and passive ions transports.

Question 8

wherein the nephron can you find specialized reabsorption?

Answer 8

Distal Convoluted Tubule

Question 9

What part of the nephron regulates how much water to retain or to pee out?

Answer 9

Collecting duct

Question 10

how is water permeability at the collecting duct regulated?

Answer 10

Different hormones
ADH - (+) –> permeability of water

there are three important components to this system: 1) renin, 2) angiotensin, and 3) aldosterone. Renin, which is released primarily by the kidneys, stimulates the formation of angiotensin in blood and tissues, which in turn stimulates the release of aldosterone from the adrenal cortex.

Constricts resistance vessels (via AII [AT1] receptors) thereby increasing systemic vascular resistance and arterial pressure
Stimulates sodium transport (reabsorption) at several renal tubular sites, thereby increasing sodium and water retention by the body
Acts on the adrenal cortex to release aldosterone, which in turn acts on the kidneys to increase sodium and fluid retention
Stimulates the release of vasopressin (antidiuretic hormone, ADH) from the posterior pituitary, which increases fluid retention by the kidneys

Question 11

why do alcohol and caffeine make you dehydrated (pee more) ? does it make your collecting duct less permeable to water and so more water leaves your system? can they do that? or what do they do?

Answer 11

Ethanol and caffeine reduce vasopressin (ADH) secretion. The resulting decrease in water reabsorption by the kidneys leads to a higher urine output.

Question 12

what allows for the reabsorption of water into the collecting duct? what drives this movement of water?

Answer 12

• Aquaporin.
• ## The concentration gradient of the medulla

Question 13

What is ADH? and how does it actually change the permeability of the collecting duct to water?

Answer 13

• ADH stands for antidiuretic hormone (ADH), another name for Vasopressin.
• It’s a hormone that increases the expression of aquaporin on the surface of the collecting duct – activating aquaporin. Aquaporin is in its inactivated state in the absence of ADH.

Question 14

Where can you find the hormone Aldosterone and what does it do?

Answer 14

• distal tubule – reabsorption of ions.

Aldosterone stimulates Na+ and water reabsorption from the gut, salivary and sweat glands in exchange for K+. Aldosterone stimulates secretion of H+

Question 15

How does the kidney respond when blood pressure drops?

Answer 15

It releases renin –> systemic vasoconstriction and increase aldosterone release which is founded at the DCT but is also present at the collecting duct.

Question 16

What does aldosterone do? how is this important in regulating blood pressure?

Answer 16

• It increases Na+ reabsorption which makes the blood more concentrated, which in turn triggers the release of ADH (vasopresin) to balance out solute concentration.
• increase blood volume –> increase blood pressure.

Question 17

why how low blood pressure affect perfusion and filtration rate? how is this get fixed and what is a potential side effect of such a response?

Answer 17

• We won’t be able to perfuse our organs that well and the filtration is also low.
• systemic vasoconstriction to increase blood pressure but that would also decrease the hydraulic pressure required for filtration since we won’t have enough blood volume to go through the glomerulus. Less blood, less blood out. We haven’t really increased the hydraulic pressure for filtration.

Question 18

what is the name of the hormone that is released by the kidney in the case of low blood pressure? what does it do?

Answer 18

Renin

• systemic vasoconstriction
• release of adosterone (reabsorption of Na+)

Question 19

What is being released by the kidney in case of high blood pressure? and what does it do?

Answer 19

• oxygenated blood is pumped out from the right side of the heart into the aorta.
• high blood pressure is sensed by the stretch of the atria.
• ANP is then released. It does the complete opposite things that renin do. It will in fact inhibit renin release.

Atrial natriuretic peptide (ANP) or atrial natriuretic factor (ANF)

Question 20

what are the two systems in the body that can control the pH level? which one responds faster?

what are the systems in our body anyway?
- Cardiovascular. 
- Nervous system 
- Respiratory system 
- Renal system 
- Skeletal muscle 
- Digestive muscle 
- Endocrine system 
and more

Answer 20

• The respiratory and the renal system that can control the pH level, but it’s a very slow response for the renal system. It takes days for it to kick in, whereas the respiratory system only takes mins or seconds.

Question 21

talking about pH regulation,

can CO2 dissolve in the blood plasma? what is the primary way for blood to carry carbon dioxide?

Answer 21

It reacts with water to yield carbonic acid, which then disassociatess into hydrogen atoms and bicarbonates.

This is why when you hypoventilate, the abundance of CO2 shifts the reaction to the right resulting in an accumulation of H+ making your blood acidic.

Question 22

what is the enzyme that increases the rate of carbonic acid formation?

Answer 22

carbonic anhydrase

An anhydrase is defined as an enzyme that catalyzes the removal of a water molecule from a compound,

Question 23

Besides secreting H+ ions into the urine, what else can the renal system reduce or increase the pH level? what are the other products on the right-hand side of the equation?

Answer 23

• Bicarbonates.

- reabsorption of bicarbonate will reduce H+ level.