Regulation of fluid balance and hormonal control of blood pressure

Question 1

Name the two types of body fluids.

Answer 1

1. Extracellular Fluid (ECF)- compromises about 40% of all body fluids.
2. Intracellular Fluid (ICF)- compromises of 60% of all body fluids and is found within cells.

Question 2

Name the two parts that extracellular can be sub divided into.

Answer 2

1. Interstitial fluid (outside cells and inbetween)

2. Intravascular fluid- blood plasma

Question 3

What does the term ‘insensible’ loss of water from the body mean?

Answer 3

Loss of water through breathing.

Question 4

What is blood volume determined by?

Answer 4

It is determined by the amount of water and sodium ingested,excreted by the kidneys into the urine, and lost through the GI tract,lungs and skin.

Question 5

The greater volume of fluid does what the arterial wall?

Answer 5

It creates greater pressure against the walls which causes a rise in blood pressure. Conversely, a lower arterial blood volume results in lower arterial blood pressure.

Question 6

What hormone is released to control BP in the long term.

Answer 6

ADH

Question 7

Where is ADH secreted and stored.

Answer 7

1. It is secreted in the hypothalamus

2. It is stored in the posterior pituitary

Question 8

What is the role of ADH.

Answer 8

It tells your kidneys how much water to conserve. ADH constantly regulates and balances the amount of water in your blood.

Question 9

Identify the receptors,controller and effectors in the long term regulation of blood pressure by ADH.

Answer 9

1. Receptor- Osmoreceptors and Baroreceptors
2. Controller- Hypothalamus (ADH)
3. Effectors- ADH

Question 10

What is RAAS?

Answer 10

Renin-Angiotensin-Aldosteron System

Question 11

What specialised cell in the kidneys secrete renin?

Answer 11

Juxtaglomerular cells

Question 12

When Renin is secreted what does it help produce and convert?

Answer 12

Renin causes angiotensinogen to be converted to angiotension I

Question 13

Describe what happens to Angiotension I

Answer 13

It travels via the circulation to the small blood vessels in the lungs where it is converted into angiotension II by an enzyme called ACE.

Question 14

State some of the actions of Angiotenin II.

Answer 14

1. Causes vasoconstriction and increases peripheral resistance and aids venous return.
2. Stimulates aldosterone secretion to increase sodium reabsorption and therefore water reabsorption too.
3. Stimulates thirst sensation
4. Stimulates ADH secretion to increase water reabsorption.

Question 15

What are the first line treatment that reduces hypertension.

Answer 15

Diuretics

Question 16

What is the function of diuretics?

Answer 16

Cause excess water to be excreted by the kidneys.

Question 17

What is the function of Loop diuretics.

Answer 17

They act on the loop of Henle by inhibiting the reabsorption of sodium.
Sodium is passed on to the collecting ducts where it attracts large volumes of water and continues on to the bladder from where it is excreted.

Question 18

What are thiazides?

Answer 18

They are the most commonly used diuretics. They inhibit sodium reabsorption at the beginning of the distal convoluted tubule. They are less powerful than the loop diuretics.

Question 19

What affects does ACE inhibitors have on the body?

Answer 19

It treats hypertension.

They decrease blood pressure by producing vasodilation and inhibiting the formation of Angiotensin II.