Alterations in fluid and electrolytes, patho

Fluid and electrolyte and acid-base balances

• Electrolytes significantly affect all cell functions, and are maintained within a narrow range primarily by the kidneys. Hydrogen concentration is controlled by buffers in an imbalance results and acidosis or alkalosis. Fluids and electrolytes are present and body cells, in the tissue spaces between the cells, and in the blood that fills the vascular compartment. Body fluids, transport, gases, nutrients, and wastes; help generate the electrical activity needed to power body functions; 

• Take part in the transforming of food into energy; and otherwise maintain the overall function of the body.
  
  

• Fluid volume in composition remain relatively constant in the presence of wide range of changes in intake and output, condition such as environmental stresses and disease can impair intake, increase losses, and interfere with mechanisms that regulate fluid volume, composition and distribution.
  
  

• The need for precise regulation of hydrogen ion balance is similar in many ways to that other other ions in the body. Many conditions, pathological, or otherwise, can alter hydrogen, concentration and acid base balance.

Body fluids are distributed between the

intracellular fluid (ICF) and extracellular fluid (ECF) 

What consists of fluid contained within all the billions of cells in the body. It is the larger of the two compartments, with approximately 2/3 of the body water and healthy adults.

ICF compartment

Read the description, then determine if this is, ICF or ECF

• fluid inside the cells

• 2/3 of bodily water (contains majority of body water)

• contains large amounts of potassium; moderate magnesium; small amounts of sodium, chloride, bicarbonate, and phosphorus; and almost no calcium

Intracellular fluid (ICF)

Read the description, then determine if this is, ICF or ECF

• fluid outside the cells incluiding intersitial (spaces between cells and vessels) and intravascular space (inside vessels)

• 1/3 of bodily water

• contains large amounts of Sodium and Chloride; moderate amounts of bicarbonate, but very little postassium, magnesium, calcium, and phosphorus

• serum blood tests measure ECF values

Extracellular fluid (ECF)

Serum blood tests measure what values?

ECF values

The ICF compartment is the larger of the two compartments, with approximately 2/3 of the body water and healthy adults. Where is the remaining body water located?

1/3 of body water is in ECF compartment, which contains all of the fluids outside the cells, including those in the interstitial or tissue spaces a blood vessels

The ECF, including blood plasma and interstitial fluids, contains large amounts of sodium and chloride and moderate amounts of bicarbonate, but only small quantities of…..

potassium, magnesium, calcium, and phosphorus

The ICF contains almost no…..

calcium

What is the most abundant intracellular electrolyte?

potassium

What serves as the the primary barrier to the movement of substances between ECF and ICF compartments.

cell membrane

Body fluid compostition

1. factors that influence fluid status: age, gender, body fat

2. water accounts for 60% of total body weight

3. 2/3rds ICF (40% TBW)

4. 1/3 ECF (20% TBW)

   1. plasma : 5% (fluid in tissues)

   2. Interstitial : 14% (fluid in tissues)

   3. Transcellular : 1% (fluid in unusable spaces (ex: fluid in joint spaces))

Body water in the average adult person assigned male of birth is about is about what percent?

60% of body weight(or about 42 L of water)

Body water is distributed between the ICF and ECF compartments.

The fluid in the ICF compartment constitutes approximately _____% of total body weight

40%

Body water is distributed between the ICF and ECF compartments.

The fluid in the ECF compartment constitutes approximately _____% of total body weight

20%

The fluid in the ECF compartment is further divided into two major subdivisions, what are they?

• The plasma compartment, which constitutes approximately 5% (1/4) of the ECF

• The interstitial fluid compartment, which constitutes approximately 14% (3/4) of the ECF

• A third, usually minor, subdivision of the ECF compartment is the transcellular compartment. Normally, only approximately 1% of ECF is in the transcellular space (ex: fluid in joint spaces)

The ICF volume is regulated by?

proteins and organic compounds within the body cells and by water and that moves into and out the cell

in the ICF, most cell membranes allow what to pass and is semi-permiable to everything else?

water

• water moves between the ECF and the ICF as a result of osmosis

  •  osmotically, active proteins, and other organic compounds cannot pass through the membrane

In the ICF, How does water pass out of the cell?

osmosis

Water entry in the cell is regulated by what?

the amount of osmotically active substances that cannot pass the semiperimiable membtane

The ECF is divided into what compartments?

•  Vascular

  •  contains blood, which is essential to the transport of substances, such as electrolytes, gases, nutrients, and waste products through the body

• Interstitial

  • The fluid in the interstitial spaces acts as the transport for gases, nutrients, wastes, and other materials that move between the vascular compartment and the body cells

  • Interstitial fluid also provides a reservoir from which the vascular volume can be maintained during periods of hemorrhage or loss of vascular fluid

• Transcellular spaces

The vascular compartment of the ECF contains what?

contains blood, which is essential to the transport of substances, such as electrolytes, gases, nutrients, and waste products through the body

What is the movement of particles along a concentation gradient from an area of higher concentration to lower concentration.

diffusion

How does diffusion work?

• All molecules and ions, including water and dissolved molecules, are in constant random motion.

  • It is the motion of these particles, each colliding with one another, that supplies, the energy for diffusion. Because there are more molecules and constant motion in a concentrated solution, the particles move from an area of higher concentration to one of lower concentration.

what is the movement of water across a semipermeable membrane down a concentration gradient from an area with less particles to the side with more particles

osmosis

How does osmosis work?

• As with particles, water diffuses down its concentration gradient, moving from the side of the membrane with lesser number of particles and greater concentration of water to decide with a greater number of particles and lesser concentration of water.

  • As water moves across the semipermeable membrane, it generates a pressure called the osmotic pressure.

  • The magnitude of the osmotic pressure represents the hydrostatic pressure (measured in milliliters of mercury [mm Hg]) needed to oppose the movement of water across the membrane 

What is the pressure generated as water moves across the semipermeable membrane?

osmotic pressure

What is osmolality?

• osmolar concentration in 1 kg of water

• normal values : 275-295 mOsm/ kg

• determined by concentration of particles: Na+, Cl-, HCO3, glucose, urea, proteins, etc

•  is used to describe fluids inside the body

• Because 1 L of water weighs 1 kg, the terms osmolarity and osmolality are often use interchangeably.

What is the tension that the effective osmotic pressure of a solution with impermeable solutes exerts on a cell size becasue of movement of water across the cell membrane?

tonicity

If you give a solution (IV) it will be in the vessels. What will happen to the cell?

• isotonic: ECF has same osmolality as ICF; cells neither shrink nor swell

• Hypertonic: ECF has higher osmolality than ICF; water leaves ICF to ECF and cells shrink

• Hypotonic: ECF has lower osmolality than ICF, water moves from ECF to ICF and cells swell

ECF has same osmolality as ICF; cells neither shrink nor swell

isotonic

• ECF has higher osmolality than ICF; water leaves ICF to ECF and cells shrink

hypertonic

ECF has lower osmolality than ICF, water moves from ECF to ICF and cells swell

hypotonic

Hypotonic solution (dilute), what happens to cell?

swollen red blood cell

Isotonic solution (normal), what happens to cell?

normal red blood cell

Hypertonic solution (concentrated), what happens to blood cell

shrunken (crenated) red blood cell

What is the movement of fluids, gasses and waste between blood and body tissues?

capillary fluid exchange

Identify the type of pressure:

• controlled by pressure within the capillary walls

hydrostatic presure (pushing pressure)

What is the pressure that pushes water out of capillary into interstital spaces

capillary filtration pressure

what is the pressure from the tissue that opposes movement of water out of the capillary

intersistial hydrostatic pressure

What pressure is controlled by substances (plasma proteins and salts) in the blood

osmotic pressure (pulling pressure)

What pressure pulls water back into capillary; generated by plasma proteins too large to pass through capillary wall

Capillary colloidal osmotic pressure

what is the pressure that pulls water out of capillary into the intersistial spaces

Tissue colloidal osmotic pressure

What system removes excess fluids in interstitium and returns it to circulation?

lymphatic system

What is edema?

• can be localized (at specific anatomic site) or generalize(fluid accumulation over the whole body)

  • allergic or inflammatory conditions cause release of histamine or inflammatroy mediators causing dilation and swelling

  • thrombophlebitis obstructs venous flow producing increased venous pressure and edema of affected part

• can be generalized (anasarca): result of increased vascular volume

• 1 L of water = 1 kg of weight

What is being described?

Swelling, an increase in interstitial fluid volume, is evident when interstitial volume exceeds 2-3 L

edema

Edema in only one location, usually related to allergic reaction or inflammation

localized edema

What is generalized edema throughout the body, usually related to excess/increased vascular volume

anasarca

Causes of edema

• Increased capillary pressure

  • increased vascular volume

    • heart failure

    • kidney disease

    • premenstural sodium retention

  • venous obstruction

    • thrombophlebitis

  • decreased arteriol resistance

• Decrease coloidal osmotic pressure

  • increased loss of plasma proteins

  • decreased production of plasma proteins

    • liver disease

    • starvation, malnutrition

• increased capillary permiability

  • inflammation

  • allergic reactions (ex: hives)

  • malignancy (ascites, pleural effusion)

• obstuction of lymphatic flow

  • malignant obstruction of lymph structes

  • surgical removal of lymph nodes

Causes of edema:

Increased capillary filtration pressure (increased pressure within capillary walls fluid out of capillary)

• increased pressure: arterial or venous

• capillary distention(stretching) due to increased vascular volume

• because of gravity, fluid tends to accumulate in dependent parts of the body (dependent edema)

  • for ex: edema of the ankles and feet become more pronouced during prolonged periods of standing

Causes of Edema,

decreased capillary colloidal osmotic pressure:

• inadequate production or abnormal loss of protein

• liver damage: plasma protein are synthesized in the liver

• most common site of plasma of plasma protein loss is in the kidneys, proteins are not supposed to be lost

• plasma protein is also lost with large areas of skin damage

• plasma proteins are evenly distibuted throughout the body, so edema due to decreased capillary colloidal osmotic pressure affects tissues in nondependent body parts (ex. face )

Causes of edema,

Damage to capillary wall

• increaes capillary permeability allowing plasma proteins to leak into interstitial spaces, increasing tissue collodial osmotic pressure

  • lymphedema: lymph system cannot remove & return excess fluid volumes

    • infection

    • trauma

    • removal of lymph structures due to cancer surgery

    • malignant involvment of lymph structure

What is lymphedma ?

• lymph system cannot remove & return excess fluid volumes

  • infection

  • trauma

  • removal of lymph structures due to cancer surgery

  • malignant involvment of lymph structure

causes of edema:

increased capillary permeability

• When the capillary pores become enlarged or the integrity of the capillary wall is damaged, capillary permeabilty is increased.

  • When this occurs, plasma proteins and other osmotically active particles leak into the interstital spaces, increasing the tissue colloidal osmotic pressure and therby contributiong to the accumulations of intersistal fluid

    • conditions that increase capillary permeability: burn injury, capillary congestion, inflammation, and immune respsonses

Manefestations of edema:

• determined largely by amount of fluid and location

• edema of brainm larynx or lungs may be life threating

• edema in joints may not be life threatining but may limit mobility and quality of life

• may indicate disease, (ex: congestive heart failure (CHF))

• increases to distance of diffusion for O2, nutrients and waste

• may compress blood vessels (compartment syndrome)

• visible

  • swelling

  • pitting (if pushed down and leaves indent in skin)

    • occurs when accumulation of interstitial fluid exceeds absorptive capacity of tissue gel

  • possible disfiguration

• non-visible:

  • impared O2 delivery to affected area : hypoxia

  • increased risk of tissue damage

  • compressed blood flow : deceeased perfusion

Manefestations of visble edema

• swelling

• pitting (if pushed down and leaves indent in skin)

  • occurs when accumulation of interstitial fluid exceeds absorptive capacity of tissue gel

• possible disfiguration

Manefestations of non-visible edema:

• impared O2 delivery to affected area : hypoxia

• increased risk of tissue damage

• compressed blood flow : deceeased perfusion

manefestations of edema, Third space accumulation

• loss or trapping of ECF in the transcellular space (not vascular or intersitstial)

• fluids are not avaible for metabolic processes

• examples:

  • Pericardial effusion: pericardial sac

  • ascites: abdominal cavity

  • pleural effusion: pleural cavity

What is third space fluid accumulation in the peritoneal cavity (abdomen)

ascites

What is accumulation of fluid in the pleural cavity

pleural effusion

What is the accumulation of fluid in the pericardial sac?

pericardial effusion

What is perfusion?

Delivery of oxygen to tissues via arteries; dependent on vessel diameter, volume, and resistance

total body water varies with …

sex and weight

• men : 60% TBW

• women 50% TBW

Fat has much _______ water than skeletal muscle

less

Total body water _____ with age

decreases

All healthy people requre approx. how much water to metabolize what?

• 1 mL of water to metabolize 1 calorie

Main source of water is by?

oral intake of liquids and solid foods

the largest loss of water occurs through the …

• kidneys

  • even when oral intake is witheld kidneys continue to produce urine to eliminate metabolic waste

• skin

• lungs

• GI tract

Blood pressure is needed pressure to do what…

perfuse organs and cells

• we need pressure in our system to perfuse(deliver blood to ) our organs and cells