Lecture 4

Question 1

What is the plasma volume of a 70kG man?

Answer 1

0.6 x 70 = 42L (equation is 0.6 x weight in Kg)

Question 2

What is 2/3 of the plasma?

Answer 2

It is intracellular

Question 3

What is 1/3 of the plasma?

Answer 3

It is extracellular

Question 4

What does the intravascular component contain?

Answer 4

It contains blood which consists of cells and plasma

Question 5

What do the doctors do if you have been vomiting and had diarrhoea for a few days?

Answer 5

Isotonic solution is the best type to rehydrate you

Question 6

What is a hypotonic IV solution able to treat?

Answer 6

Diabetic ketoacidosis or cellular dehydration

Question 7

What is a hypertonic IV solution able to treat?

Answer 7

Someone in critical care, to increase intravascular fluid volume - Brain injuries to reduce intracranial pressure

Question 8

How would you make an isotonic IV?

Answer 8

Add glucose to water to make it isotonic

Question 9

What is dextrose?

Answer 9

It is chemically identical to blood sugar and glucose.

Question 10

is dextrose a good IV fluid for someone that has an diarrhoea?

Answer 10

Yes as the water will diffuse across all compartments, only 80ml stays in the blood vessels so its a very good replacement fluid

Question 11

What is the best fluid for someone that has diarrhoea?

Answer 11

Saline - it only ends up in the interstitial and in the blood vessels.

Question 12

How much saline will end up in the vascular space and in the interstium?

Answer 12

250ml in the vascular space and 750mls in the interstitum

Question 13

What is the circulating volume?

Answer 13

Plasma volume and how much pressure there to be able to be pumped around the body

Question 14

Why would there be a decrease in circulating volume?

Answer 14

If the blood pressure failing or if the blood vessels are empty

Question 15

What does the kidney do if it wants to expand and increase blood pressure?

Answer 15

It will reabsorb Na+/Cl- which will = an increase in plasma volume - the kidney prefers to absorb Na+

Question 16

What do the kidneys release in response to a drop in blood pressure?

Answer 16

It will release renin

Question 17

What is the reabsorption rate for the PCT?

Answer 17

50-60%

Question 18

What can work for kidney expansion?

Answer 18

Salty water

Question 19

What happens if the kidney decide to absorb salt?

Answer 19

There will be a much bigger expansion of the intracellular compartments whereas if it was to absorb water the water would be distributed around the body.

Question 20

What is the equation for BP?

Answer 20

CO x peripheral resistance

Question 21

What are the three steps of volume regulation?

Answer 21

Monitoring, signalling and action at targets

Question 22

What is renin produced by?

Answer 22

By the kidneys when your blood pressure decreases

Question 23

What does renin allow the conversion of?

Answer 23

It allows the conversion of angiotensin which tells the body to absorb salt, vessels to constrict and tells the adrenal glands to make aldosterone

Question 24

What does aldosterone do?

Answer 24

It helps control the balance of water and salt in the kidneys by keeping Na+ and releasing K+.

Question 25

What is the neuronal control that activates the fight or flight simulation?

Answer 25

The sympathetic system

Question 26

What does ADH do?

Answer 26

It is an anti-dietetic hormone, and can constrict the blood vessels to help the kidney control how much water is in the body.

Question 27

What does the juxtaglomerular apparatus do?

Answer 27

It regulated the glomerular filtration rate, if the pressure is low then renin will be made.

Question 28

What does renin allow the conversion of?

Answer 28

Angiotensinogen or angiotensin 1

Question 29

What is the activating enzyme that helps with the conversion of angiotensin 1 to 2?

Answer 29

ACE inhibitor

Question 30

What is a symptom from taking an ACE inhibitor?

Answer 30

A cough

Question 31

What does angiotensin 2 do?

Answer 31

Regulates Na+ reabsorption in the proximal tubule, acts directly on the blood vessels to increase the blood pressure

Question 32

What is ANP?

Answer 32

It is a atrial natriuretic peptide - it is the only hormone that decreases plasma volume

Question 33

When is ANP made?

Answer 33

When there is heart failure and the body is full of fluid - it is a mechanism used for the body to waste salt

Question 34

What detects osmolarity?

Answer 34

The hypothalamus

Question 35

What controls thirst?

Answer 35

The hypothalamus, it is the primary reflex

Question 36

What happens if you become hyperosmolar?

Answer 36

You could have fits or seizures

Question 37

How could the body adjust its osmolarity?

Answer 37

By changing the amount of water in the body, or can lose water and concentrate it

Question 38

What happens if you are hypotonic?

Answer 38

You lose thirst, kidney gets rid of free water

Question 39

What is diabetes inspidius?

Answer 39

When the kidney doesn’t respond to ADH - it causes fluids in the body to become unbalanced

Question 40

What is a cranial version of Diabetes - also called central diabetes inspidius

Answer 40

When the body has a lower amount of normal ADH, can occur from brain trauma, and can cause bed wetting. Inability of the brain to release ADH

Question 41

What is Nephrogenic diabetes?

Answer 41

It is caused by the inability for the kidney to recognise ADH, as a result too much fluid will be flushed out in the urine.
Symptoms are chronic excessive urine production and excessive thirst