Chapter 5B - Applied Physiology Flashcards
Filtration – definition
Involves passing body fluids and other dissolved elements through a selectively permeable membrane (like the capillary wall) that allows some things, such as water, sugar and protein to pass, but keeps the red blood cells inside the capillary
requires hydrostatic pressure like perfusion pressure, or blood pressure
Perfusion – definition
To pour through – so it refers to the pumping of blood through blood vessels under pressure (perfusion pressure)
Osmosis – definition
The process by which water is pulled towards a crystalloid (a salt or sugar)
– the water (a solvent) is pulled towards a salt or sugar (a solute)
usually across a semi-permeable membrane
Diffusion- definition
The process by which a gas, or a substance in solution, spreads (because of the moment of its particles) from areas where there are a lot of them to areas where there are less, to evenly fill all the available space
Molecules are in continuous random movement
– he speeds up this movement
– cold slows it down
Ischemia - definition
The lack of perfusion. An area of tissue is not getting supplied with enough blood
Homeostasis- definition
The process by which the body maintains balance and equilibrium between all body parts – maintaining the internal environment
Edema – definition
The buildup of fluid in the tissues usually interstitial
sometimes called third spacing because the interstitial space is the third space, after intravascular and intracellular
List the important electrolytes (7)
- Sodium Na+
- Potassium K+
- Calcium Ca++
- Bicarbonate HCO3-
- Magnesium Mg++
- Chloride Cl-
- Phosphate PO4—
Sodium – describe
Most common electrolyte, is important in the cellular depolarization, nerve conduction, muscle contraction (including the heart and brain) important in control of water balance
– attracts and hold water so it tends to increase BP
most common extracellular ion
Potassium – describe
Important in cellular depolarization, nerve conduction, muscle contraction (including the heart and brain), and the electrical stability of the heart
– intake tends to lower BP
– most common intracellular
– often lost with diuretic use
– vital to normal heart function
– too much or too little will cause cardiac dysrhythmias
Calcium - describe
Important in the mechanical contraction of muscles, and nerve conduction of signals
To little –> tetany
Too much -> muscle weakness
Bicarbonate – describe
Important in maintaining acid – base balance
-it will buffer acids
pH – define
is a unit of measurement of acid/base balance – it is a scale of 1 to 14 where 1 is the strongest acid, and 14 is the strongest alkali (base) and 7 is neutral (the pH of water). The pH of blood is 7.4, so we are slightly alkaline
Acidosis – describe the effects on the body
Causes cells to become permeable, and leak fluids. It causes cells to depolarize and relax, being unable to repolarize.
This will also lead to vasodilation
Alkalosis – describe the effects on the body
Is also bad for cells, causing them to become irritable. This may lead to twitching or cramping.
This will also lead to vasoconstriction
List and describe the three major body fluid compartments
- Intravascular = within the vessels
- Interstitial = between the cells
- Intracellular = within the cells
What is the percentage of water for the 3 major body fluid compartments
Intravascular = 10% of body water (this determines tissue perfusion)
interstitial = 25% of body water (16% of body weight)
intracellular = 65% the body water (40% of body weight)
Describe how fluid moves across the three body fluid compartments
Fluid moves by perfusion (pressure filtration), then by osmosis
Describe “body fluids” and list the components
Body fluids are composed of water and substances dissolved in it: electrolytes (charged ions), and non-electrolytes such as glucose, proteins, urea, etc.
60% of the bodyweight is water
– the loss of 1% will cause a compensation effort to begin
- loss of 10% will cause a risk of collapse and possible death
Water acts a lubricant, assists temperature regulation and the transportation of nutrients, wastes, and hormones.
Describe the bodies process for maintaining water balance
The hypothalamus helps regulate water balance by containing the body’s thirst center. It also communicates with the pituitary gland which causes the kidneys to save or eliminate water
Thirst cannot be relied upon to maintain fluid balance – you are usually a quart low before thirst kicks in to help you drink
Acute volume loss - causes (4)
- Hemorrhage
- diarrhea
- vomiting
- burns
Occurs in minutes to hours
Acute volume loss – signs and symptoms (7)
- Tachycardia
- pale, cool, diaphoretic skins
– delayed capillary refill
– Thirst
– hypertension
– nausea
– altered level of consciousness
Chronic volume loss (dehydration) – causes (3)
– Poor intake
– fever
– chronic illnesses
Chronic volume loss (dehydration) – signs/symptoms (7)
– Dry mucous membranes – poor skin turgor (tenting) – increased thirst – decreased urine output – hypertension – altered level of consciousness - sunken fontanelles (in infants)
Hypervolemia (overhydration) – causes (4)
- CHF
– liver disease
– kidney failure
– drinking too much water
Hypervolemia (overhydration) – signs/symptoms (6)
– Rapid weight gain – JVD – peripheral Edema – ascites – SOB – crackles
Metabolism – define
The process where the cells of the body take in fuel and oxygen and “burn” it, creating energy for body processes, and releasing heat and other by-products such as carbon dioxide (CO2) H2O and possibly other waste products also
– We use oxygen to oxidize carbohydrates, proteins and fats to produce the energy needed for life processes (in the form of high energy packets called ATPs = that is a triphosphate)
Describe the function of the cell as it applies to metabolism
The Cells take up oxygen from the blood (and interstitial fluid) by diffusion, and sugar and nutrients by active transport (usually using insulin). The mitochondria oxidize the sugar producing energy (in the form of ATP’s) and waste products such as heat and carbon dioxide. ATPs are necessary for all bodily functions, from muscle contractions (think diaphragm and heart) and nerve conduction, etc.
- this is called the critic acid or Krebs cycle
Mitochondria – describe
Are small organelles found inside the cells that operate as small energy factories. The sugar and oxygen go here, and the mitochondria manufacturer Adenosine triphosphates (provides the energy to make the nerves and muscles work).
- we give the patient oxygen so that the mitochondria can make ATP’s
Lysosomes – describe
Are small organelles found inside cells that contain enzymes that will dissolve the cells and completely destroy it if they are released. They are there to erase the cell from existence upon its death. Otherwise we would clog up with a dead cell debris.
- These cause problems in cases of prolonged anoxia, as they burst and release the enzymes, tearing apart surrounding cells
Cell membrane – describe
The outer wrapper on a cell keeps the right things in, and prevents the wrong things from coming in. It has pores or openings like doors through which it’s food enters, or wastes exit. Acidosis makes this membrane very leaky, basically leaving all the doors open
– high levels of oxygen or lowering carbon dioxide levels by hyperventilation of patients helps stabilize of these so membranes
Catabolism - describe
Is the process described where foods are broken down to liberate or produce energy, or is the wasting process of breaking down tissues and muscles
Animalism – describe
Is the process of building up or storing things for later use. So, the making of fat or glycogen (the end storage forms for foods we eat, or the building of muscle, etc. Is an anabolic process) any excess calories eating get stored as fats
- insulin is anabolic
Describe the dietary food sources and their energy amounts
Carbohydrates = 4 kcal/Gram = sugars and starches
= simple = various types of sugars
= complex = starches
Proteins = 4kcal/gram = amino acids
Fats (lipids) = 9 kcal/gram = fatty acids
Alcohol = 7 kcal/gram = ethanol
Aerobic metabolism – defined
Metabolism in the presence of oxygen
Aerobic metabolism – list the end products
End products are ATPs (Energy units), carbon dioxide and water and other cellular wastes depending on the energy substrate (whether carbohydrates were burned or proteins or fats) energy produced per unit of sugar is 38 ATPs
Anaerobic- define
Metabolism without the presence of oxygen
Anaerobic metabolism – list the end products
End products are ATPs (only 2), lactic acid and other cellular waste
– the lactic acid waste cannot be breathed off in the lungs and therefore is very difficult to eliminate
- it takes the kidneys much longer to do it, and therefore is considered a strong acid
– it will need to be buffered (neutralized) by bicarbonate
Describe the unique metabolism of the brain
Because the capillaries of the brain are glued together especially tightly, they create something called the blood brain barrier that prevents most things, including dangerous ones, from getting into the brain.
The brain thus relays on sugar and oxygen for metabolism – it is unable to burn protein or fat for energy
Vulnerable to extreme low blood sugar levels
Which neurologic function is the earliest to be adversely affected by a lack of oxygen
Level of consciousness becomes quickly depressed
the brain is very sensitive to hypoxia
Biological death - define
Is irreversible/permanent brain death due to a lack of oxygen
– it occurs 4-6 minutes after clinical death
50% chance of rain damage at four minutes
87% chance of brain damage at six minutes
Clinical death
Occurs the moment the heart and lungs stop functioning
– it may be reversible with CPR
How long can the brain survive without oxygen
4 to 6 minutes
but actually four minutes is a 50-50 chance of permanent brain damage
How long can the heart survive without oxygen
1-2 hours
How long can the kidneys survive without oxygen
One to two hours
How long can the muscles survive without oxygen
1-2 hours
Cold – describe the effects body temperature has on oxygen consumption but the tissues
Cold slows consumption of oxygen as metabolism is turned down
Cold - effects on O2 consumption by the tissues
In hypothermia states, as in drowning and other cold related situations the brain can last much longer than 4 to 6 minutes without oxygen. There have been successful after 40 minute with no oxygen reaching the brain in Cold water drowning
Heat – describe effect temperature has on oxygen consumption by the tissues
Heat increases oxygen consumption
Heat – significance of effect on oxygen consumption by the tissues
Fevers often present with increased pulses and increased respiratory rates due to higher oxygen burn rates
Osmotic pressure – defined
The theoretical amount of pressure it would take to prevent this water movement
Oncotic pressure
The process by which water is pulled towards a colloid (protein and starch)
just like osmosis, except it involves colloids instead of crystalloids
Glycolysis
The breakdown of glucose (sugar) to produce energy
Glycogenesis
The process of creating glycogen for storage in the liver and muscle tissue
Glycogenolysis
The process of breaking down glycogen to release sugar
the pancreatic hormone glucagon does this
Gluconeogenesis
The process by which proteins can be converted to sugar for energy release
Oral intake – described in the fluid intake
60% in the form of fluids
30% in foods (solids)
10% as a result of metabolism
Describe daily fluid elimination
60% in urine
6% in feces
6% in sweat
28% in respiratory losses
Describe
Fluid in jested daily into G.I. tract = 2000 mL
Endogenous secretion into G.I. tract = 7000 mL
-Salivary glands = 1500 mL
-stomach secretions = 2500 mL
-bile = 500 mL
-pancreatic juice = 1500 mL
-intestinal secretions = 1000 mL
Describe daily gastrointestinal elimination
Reabsorbed from Jejunum = 5,500 mL
- from ileum = 2,000 mL
- from colon = 1,300 mL
Fluid lost in stools = 200 mL
What does pH stand for
Power of hydrogen
State the significance of pH
Your body, your nerves, your muscles, your cells will not function properly unless they are in a balanced pH solution
What is the pH of blood
7.35–7.45
Describe a pH balance is maintained or how it can be restored to If altered
Primary control through chemoreceptors and respiratory elimination of carbonic acid
- Respiratory buffering is very rapid - in minutes
secondary control is through a buffering system involving the kidneys in bicarbonate (sponging of hydrogen ions)
- kidney buffering is very slow – in hours or delays
Explain how bicarbonate helps eliminate acidosis
Acidosis in the body is in actuality in excess of free hydrogen ions in solution. Bicarbonate can sponge them up by combining with them to form carbonic acid which is then breathed off
the kidneys can make bicarbonate and use it to buffer acidosis, but that would take all day, excreting the hydrogen (acid) and bicarbonate in the urine. (If the lungs cannot breathe it off)
Magnesium – describe
Important in activating many enzymes also works opposite calcium in electrical conduction and depolarization of nerves and muscles
so magnesium sulfate is sometimes used to stop muscular contractions, as in premature labor
Chloride – describe
Combined with sodium and helps maintain water balance and osmotic pressure in the body
Phosphate – describe
Important in high-energy bonds as in there is interest phosphate, also has some pH buffer ability
Potassium - clinical significance
The magnitude of potassium gradient across cell membranes determines excitability of nerve and muscle cells, including the myocardium. Minor changes in serum potassium concentration can have major effects on cardiac rhythm and function. Of all the electrolytes, rapid changes in potassium concentration can cause the most immediate life threatening consequences
Changes in pH inversely affect serum potassium. Acidosis (low pH) leads to an extra cellular shift of potassium, thus raising serum potassium. Conversely, high pH (alkalosis) shifts potassium back into the cell, lowering serum potassium
Hyperkalemia – physical symptoms
Includes ECG changes, weakness, ascending paralysis, and respiratory failure. ECG changes suggestive of hyperkalemia include Peaked T waves, flattened P waves, prolonged PR interval is (1st° heart blocks), widened QRS complex and others. Tenting of T waves is one of the prominent early ECG changes. If untreated, hyperkalemia causes progressive heart dysfunction, leading eventually to asystole.
Hypokalemia – physical symptoms
Include weakness, fatigue, paralysis, and respiratory difficulty. ECG changes suggestive of hypokalemia include the presence of U waves, T wave flattening, and other dysrhythmias including PEA or asystole
Sodium – clinical significance
Is the major positively charged ion in the extracellular space and the major intravascular ion that influences serum osmolality. Acute changes in serum sodium will produce acute free water shifts into and out of the vascular space until osmolality equilibrates in these compartments. An acute fall in the serum sodium and an acute fluid shift into the interstitial space may cause cerebral edema
Magnesium – clinical significance
Is the fourth most common mineral in the human body. It is required for the action of many important enzymes and hormones. It is necessary for the movement of sodium, potassium, and calcium into and out of the cells. It is also important in stabilizing excitable membranes and useful for atrial and ventricular of arrhythmias
Calcium – clinical significance
Is the most abundant mineral in the body. It is essential for bone strength and neuromuscular functions and plays a major role in myocardial contractions. Half of all calcium in the ECF is bounded to albumin; the other half is in the biologically active, Ionized form
Serum ionized calcium is pH depended. Alkalosis reduces serum calcium levels. Conversely, the development of acidosis will produce an increase in serum calcium.
Calcium antagonizes the effects of both potassium and magnesium at the cell membrane. Therefore, it is extremely useful for treating the effects of hyperkalemia and hypermagnesemia
Tonicity – describe
The osmolality of a solution in relation to plasma
Hypotonic solutions - examples
0.45% NS (half normal saline)
D5W
Hypotonic solutions – use
As a lifeline for later drug administration, the Florida will not remain in the vascular compartment and will therefore not predispose to fluid overload
if very hypotonic, may cause hemolysis
Has fewer particles than plasma
Isotonic solutions – example
Normal saline
Lactated Rangers solution
Isotonic solution – use
For fluid volume replacement and hypovolemia,the fluid will tend to remain in the vascular compartment at least for an hour
equal particles to plasma
at a TKO rate, this adds a tiny amount of fluid volume – so it is not a problem in CHF
Hypertonic solutions – examples
D50W D5 in the 0.45% normal saline Mannitol Sorbitol 7.5% saline with the dextran
Hypertonic solution - use
osmotically or oncotically pulls fluid across membranes D50W to replace sugar in hyperglycemia – but may cause necrosis if it extravasates
More particles than plasma
Can cause crenation of RBCs
Mannitol
Is used in cerebral edema to pull water out of the brain for elimination
Sorbitol
Is used as a cathartic with activated charcoal as it holds water in the bottle, increasing bowl elimination of the charcoal and therefore the toxin
7.5% saline with Dextran
Is highly hypertonic and provides osmotic and oncotic pull of physiologic body fluids into the vascular space for volume expansion
Alpha cells
Of the islets of langerhans secrete a hormone called the glucagon which, when released from the pancreas flows to the liver and causes the liver to convert glycogen, storage form polysaccharide to simple glucose, a monosaccharide – raising blood sugar levels.
This function is dependent upon there being adequate amounts of glycogen stored. If the patient has not eaten in sometime, such as following prolonged vomiting, they will have depleted their glycogen stores, and glucagon won’t work
Beta cells
Of the islet of langerhans secrete a hormone called insulin which, when released from the pancreas flow throughout the body and causes cells to take up sugar from the bloodstream
Delta cells
Of the islet of langerhans secrete hormones called somatostatin which, when released inhibit pancreatic function – that is, it inhibits the secretion of insulin, Glucagon, and pancreatic polypeptide (use indigestion)
hypersecretion of somatostatin from a pancreatic tumor can create hyperglycemia – and look like diabetes
