Fluid Balance Flashcards
Body’s fluid compartments
Intracellular (IFC)
Extracellular (EFC)
Intracellular (IFC);
Body’s fluid compartments
⅔ of the fluid in our bodies is in our cells
Water is what makes up the cytosol in the cytoplasm
Extracellular (EFC)
;Body’s fluid compartments
⅓ of the fluid in our body is in the EFC
This is fluid located outside of cells
Extracellular fluid compartments can be divided into two portions
- Plasma
- Fluid within blood vessels
- 20% of EFC - Interstitial fluid
- Fluid in between cells and blood vessels
- 80% of the EFC
Composition of body fluids
water
non-electrolytes
electrolytes
Water;
Composition of body fluids, osmotic power
Up to 60% of the body is made of water
Water is the universal solvent
-Things must be dissolved in solution to be biologically active
Nonelectrolytes;
Composition of body fluids, osmotic power
Organic compounds like lipids and carbohydrates
These molecules don’t dissociate when they get into water, but they do dissolved
The concentration of things dissolved in water creates a concentration gradient
- Makes water move
- Does not create as strong of an osmotic gradient/potential in comparison to electrolytes
Electrolytes;
Composition of body fluids, osmotic power?
Do dissociate in water
Inorganic salts, acids, bases, and some proteins
Since electrolytes dissociate, they contribute even more to the osmotic gradient than nonelectrolytes
Sodium (Na+) is mostly found extracellularly
Potassium (K+) is mostly found intracellularly
The composition of electrolytes in the fluid of our cells varies depending on where in the body one is observing
-Intracellular versus extracellular composition
CHEMISTRY;
composition of body fluids, and explain the osmotic power of each.
One molecule of glucose = one molecule in water
One molecule of salt (NaCl) dissociates into one Na+ and one Cl- ion.
-Creates a bigger osmotic pressure/gradient/potential
Factors that control fluid exchange
Hydrostatic pressure and osmotic gradients are the two factors that regulate fluid movement in our body
Fluid exchange between plasma and interstitial fluid
Fluid exchange between interstitial fluid and intracellular fluid
Hydrostatic pressure and osmotic gradients are the two factors that regulate fluid movement in our body;
Factors that control fluid exchange
Hydrostatic pressure
-The pressure created from fluid pushing against something
Osmotic potential
-Concentration of ions creates a gradient that causes the movement of water
Can work together, or in opposition
Fluid exchange between plasma and interstitial fluid;
What is Fluid exchange between plasma and interstitial fluid regulated by?
Regulated by hydrostatic pressure
Fluid exchange between interstitial fluid and intracellular fluid;
regulated by what?
(List the factors that control fluid exchange.)
Regulated by osmotic gradient pressure
List the routes by which water enters and leaves the body
WATER BALNCE
ELECTROLYTE BALANCE
ACID-BASED BALANCE
Water Balance; water intake
List the routes by which water enters and leaves the body
- Ingestion
- —Drinking water or getting water from other drinks
- —-Obtain water from the food we eat
- Metabolic water
- —-Oxidation generates water
- —–Anabolic reactions create water
- ———Dehydration synthesis reaction
Water Balance; water output
List the routes by which water enters and leaves the body
types?
Vaporization Perspiration Elimination Urination Vomiting -Not a normal way to lose water
Water intake = water output (typically)
Electrolyte Balance types;
routes by which water enters and leaves the body
Electrolyte intake
Electrolyte output
Electrolyte Balance:
ELECTROLYTE INTAKE
IN WHAT WAYS?
routes by which water enters and leaves the body
Ingestion
Metabolic production
Electrolyte Balance:
ELECTROLYTE OUTPUT
WHAT ARE THEY?
routes by which water enters and leaves the body
Perspiration
Elimination
Urination
Vomiting
Electrolyte Balance:
What are we talking about?
How are electrolytes not lost?
What happens when you breath out?
routes by which water enters and leaves the body
When talking about electrolyte balance, we are talking about salt balance (not only NaCl, which is table salt)
You do not lose electrolytes from vaporization
-When you breathe out, you do not lose electrolytes but you do lose water
Acid-Base Balance; Closely regulated to what? pH of blood? pH of intracellular? Source of what? ****routes by which water enters and leaves the body***
The acid-base balance of the blood is closely regulated to maintain biochemical reactions in the body
Blood pH is 7.35-7.45
Intracellular pH is a little closer to neutral (7)
Sources of H+ ions
Acid-Base Balance;
The acid-base balance of the blood is closely regulated to maintain biochemical reactions in the body
routes by which water enters and leaves the body
Every enzyme has an optimal pH range to work in
-When out of that range, the enzyme will denature and not function
Acid-Base Balance;
Blood pH is 7.35-7.45
WHY? DESPITE WHAT?
routes by which water enters and leaves the body
The body must maintain this blood pH range despite eating acidic foods
Acid-Base Balance;
Intracellular pH is a little closer to neutral (7)
WHY?
routes by which water enters and leaves the body
This is because the carbon dioxide produced in metabolic pathways creates a slightly more acidic environment
Acid-Base Balance;
Sources of H+ ions
routes by which water enters and leaves the body
Dietary
-Most of the foods that we take into the body are acidic yet we maintain a pH that is neutral or slightly on the basic side of neutral
Metabolic processes
-Breakdown of macromolecules can produce hydrogen ions
Mechanisms that regulate water input and output?
An increase in plasma osmolarity or decrease in blood volume promotes thirst
A decrease in extracellular fluid osmolarity decreases ADH production
Large decreases in blood pressure increases ADH production
Mechanisms that regulate water input and output?
An increase in plasma osmolarity or decrease in blood volume promotes thirst
A decrease in extracellular fluid osmolarity decreases ADH production
Large decreases in blood pressure increases ADH production
An increase in plasma osmolarity or decrease in blood volume promotes thirst
(mechanisms that regulate water input and output)
As the blood plasma becomes more concentrated, the body becomes thirsty in an effort to get us to drink, thereby bringing us back to a homeostatic concentration
Ions are not the only thing that can cause blood plasma to become too concentrated
—-One symptom that is indicative of diabetes is the inability to satiate thirst due to the high blood sugar causing an increase in the osmolarity of the blood plasma
A decrease in extracellular fluid osmolarity decreases ADH production
(mechanisms that regulate water input and output)
When extracellular fluid is dilute, ADH is shut off and urine production increases
—Blood plasma is the extracellular fluid
The opposite holds true
—When extracellular fluid is concentrated (high extracellular fluid osmolarity), ADH secretion increases to dilute the extracellular fluid
Large decreases in blood pressure increases ADH production
mechanisms that regulate water input and output
Blood pressure is linked to blood volume
When BP/BV significantly decrease, ADH production increases
—-This increases the amount of water being reabsorbed back into the bloodstream; therefore increasing BP/BV
Importance of ionic sodium in fluid and electrolyte balance in the body?
What is sodium a major regulator of?
Mostly exists where?
Important in what?
Sodium is the major regulator ion of fluid balance in the body
Sodium mostly exists in the extracellular fraction
—-Outside of the cells
Incredibly important in creating osmotic gradients
—–Water follows sodium
Mechanisms involved in regulating sodium (and therefore water) balance
6
- Aldosterone
- Cardiovascular baroreceptors
- Atrial natriuretic peptide (ANP)
- Estrogen
- Progesterone
- Glucocorticoids
Aldosterone;
Mechanisms involved in regulating sodium (and therefore water) balance
Corticosteroid hormone released by the cortex of the adrenal gland
Causes an increases of sodium reabsorption in the kidneys
- –Sodium moves out of the renal tubule and back into interstitial space
- ——–The sodium ultimately moves into circulation
Cardiovascular baroreceptors;
Mechanisms involved in regulating sodium (and therefore water) balance
Pressure sensors in the walls of blood vessels near the heart sense changes in blood pressure
—–These sensors respond by sending signals to the brain to modify activity of the kidneys
Cardiovascular baroreceptors
EXAMPLES? HR
Mechanisms involved in regulating sodium (and therefore water) balance
High blood pressure:
Causes a decrease in sympathetic nervous activity to the kidneys
—–Results in the dilation of the afferent arteriole
Increases filtration rate, increases the amount of Na+ and water that leaves
Blood volume and blood pressure decreases
Cardiovascular baroreceptors
EXAMPLES? LOW bp
Mechanisms involved in regulating sodium (and therefore water) balance
Low blood pressure:
Causes an increase in sympathetic stimulation of the kidneys
Results in the constriction of the afferent arteriole
Decreases filtration rate, decreases the amount of Na+ and water that leaves
Blood volume and blood pressure increases
Atrial natriuretic peptide (ANP) overview
Mechanisms involved in regulating sodium (and therefore water) balance
A hormone released by the atria of the heart in response to an increase in the stretch of the wall of the heart
ANP has multiple effects
ANP reduces renin secretion
ANP leads to a reduction in blood volume and blood pressure
A hormone released by the atria of the heart in response to an increase in the stretch of the wall of the heart
WHEN DOES THIS OCCUR?
Atrial natriuretic peptide (ANP);
Mechanisms involved in regulating sodium (and therefore water) balance
This occurs when there is more blood volume and a higher blood pressure
EFFECTS of ANP
WHAT is it?
WHAT does it decrease?
Atrial natriuretic peptide (ANP) a mechanism involved in regulating sodium (and therefore water) balance
ANP is a vasodilator
—–Increases filtration
ANP decreases ADH secretion
——This decreases the reabsorption of water
ANP reduces renin secretion
What does this cause to be reduced?
Atrial natriuretic peptide (ANP) a mechanism involved in regulating sodium (and therefore water) balance
This reduces aldosterone production
—–Decreases sodium reabsorption
What does ANP LEAD TO?
Atrial natriuretic peptide (ANP) a mechanism involved in regulating sodium (and therefore water) balance
to a reduction in blood volume and blood pressure
ESTROGEN;
mechanism involved in regulating sodium (and therefore water) balance
Causes an increase in sodium reabsorption
—–Water follows sodium
Estrogen is cyclic in women
—–Why bloating occurs during menstrual cycles
PROGESTERONE;
mechanism involved in regulating sodium (and therefore water) balance
Decreases sodium reabsorption
GLUCOCORTICOIDS
mechanism involved in regulating sodium (and therefore water) balance
Also produced in the adrenal cortex
Increases sodium reabsorption
—–Leads to an increase in blood volume and blood pressure
Acidosis
Abnormally low body pH
Respiratory acidosis
Caused by what?
What increases in the blood stream?
Caused by reduced ventilation (breathing rate)
Carbon dioxide levels increase in the bloodstream and the blood becomes acidic
——-pH decreases
Metabolic acidosis
A buildup of any other acid other than carbon dioxide in the bloodstream
Alkalosis
Abnormally high body pH
Respiratory alkalosis
Caused by rapid ventilation
Carbon dioxide levels decrease in the bloodstream and the blood becomes alkaline
—-pH increases
Metabolic alkalosis
Having too little of an acid other than carbon dioxide in the bloodstream
Three major chemical buffer systems
Bicarbonate
Phosphate
Protein
Chemical Buffer Systems
act AS WHAT?
Act as proton donors/acceptors
—-Temporarily helps to resist changes in blood pH
Bicarbonate; What reacts with what? creates what? In... in blood Can be a what? MAJOR CHEMICAL BUFFER SYSTEMS and describe how they resist pH change.
Carbon dioxide and water react to create carbonic acid
—–Carbonic acid dissociates into bicarbonate
In extracellular compartment
——-Most active in the blood
Can act as a hydrogen acceptor
PHOSPHATE;
MAJOR CHEMICAL BUFFER SYSTEMS
and describe how they resist pH change.
Buffer that operates intracellularly
PROTEIN;
MAJOR CHEMICAL BUFFER SYSTEMS
and describe how they resist pH change.
Proteins act as amphoteric molecules
- –Amphoteric molecules can act as acids or bases
- ——Most important chemical buffer for this reason
Can act in intracellular or extracellular compartment
PROTEIN;
MAJOR CHEMICAL BUFFER SYSTEMS
and describe how they resist pH change.
examples???
Myoglobin and hemoglobin is an intracellular protein that can act amphoterically
Albumin is an extracellular protein that can act amphoterically
Physiological Buffer Systems (Respiratory System)
Describe the influence of the respiratory system on acid-base balance
Slower than the chemical buffer systems, but much more powerful
——–Have 2x the power that all chemical buffer systems combined
Respiratory mechanisms;
- -If blood pH goes up (becomes more alkaline), our breathing slows down
- ——-Builds CO2 levels back up, blood becomes more acidic
How kidneys regulate bicarbonate ion concentration of the blood?
Renal Mechanisms
Types of renal mechanisms;
How kidneys regulate bicarbonate ion concentration of the blood
Reabsorption of bicarbonate
Bicarbonate synthesis
Bicarbonate excretion
Reabsorption of bicarbonate;
TYPES of renal mechanisms;
How kidneys regulate bicarbonate ion concentration of the blood
Bicarbonate leaves the filtrate and goes back into the bloodstream
Bicarbonate synthesis;
TYPES of renal mechanisms;
How kidneys regulate bicarbonate ion concentration of the blood
Kidneys can make carbonic acid
——–This carbonic acid dissociates into bicarbonate and the bicarbonate is reabsorbed back into the bloodstream
Bicarbonate excretion;
TYPES of renal mechanisms;
How kidneys regulate bicarbonate ion concentration of the blood
Kidneys can get rid of bicarbonate through secretion of bicarbonate into the tubules
- *Can substitute bicarbonate with phosphate
- *
