Alterations in Intracellular Functions, Fluid and Solute Balance, Acid / Base Balance (RRD #1 & 2)

What are four cellular-level disruptions that lead to a decrease in ATP?

hypoxia, nutritional problems, changes in the balance of electrolytes, other solutes, and acid / base balance, and changes in fluid distribution.

What are two main sequela from hypoxia?

When you are hypoxic, you are using only anerobic glycolysis for energy. This causes: 1.) deficiency of ATP for cellular functions (only 2 ATP are created) and 2. acidosis - an altered acid / base balance due to the accumulation of pyruvic acic.

What is the normal

pH range of the blood?

7.35 - 7.45. The byproducts of the body's normal metabolic activities are slightly more acidic than alkaline. To counteract that tendency, the body likes to keep a very narrow and slightly alkaline pH range in the blood. Know this fact "now and forever".

Two key nutritional needs of cells

glucose (begins the cellular metabolic pathway that leads to ATP formation) and vitamins and other substances (which form the support staff for the metabolic pathway).

What are the two functions of insulin?

1.) to bring glucose from the blood to the cells where it is used to create energy.

2.) to store excess glucose in the liver and skeletal muscles as glycogen.

What is glycogen?

Excess glucose that you eat, but don't need for immediate energy, is created and stored as glycogen in the liver and skeletal muscles for later use.

What is glycogenesis?

The process of changing un-needed glucose into glycogen.

What is hypoglycemia?

A state of low blood sugar. It typically exists when you don't eat and the availability of glucose in your blood is less than what your cells' energy needs are.

What counterregulatory hormones are released or triggered when you are hypoglycemic?

epinephrine, cortisol, growth hormone, glucagon. All of these have certain functions...which in the end prompt you to eat.

What is glycogenolysis?

The conversion of glycogen to glucose for use in the cells of the body. AKA...back-up plan #1

What is gluconeogenesis?

If glucose is unavailable or can't get into the cell and glycogenolysis has already used up the individual's available store of glycogen, the body breaks down fats and protein for energy.

What are ketones?

A breakdown product of fat and protein which can offer the body some energy. They will accumulate in the blood in sustained gluconeogenesis. The downside:

1.) ketones are acids, which creates a risk for acidosis.

2.) they can't be used by brain cells, which must have glucose for energy.

What is McArdles' disease?

an example of a glycogen storage disease

What is Type I Diabetes?

an example of gluconeogenesis taken to extreme because people with type I diabetes do not make insulin.

What is hyperketonemia?

high levels of ketones in the blood and usually also...

low blood pH / ketoacidosis, ketonuria,and acetone breath.

What type of patient might a nurse see in the USA that is at risk for vitamin deficiencies?

An alcoholic. Their diet may contain minimal iron and b vitamins which are important to cellular metabolism.

What are the symptoms of thiamine deficiency (beriberi)?

neurological symptoms / problems including Wernicke-Korsakoff syndrome (memory loss, ataxia, parasthesias)

What is diffusion?

The movement of solutes from an area of higher concentration to an area of lower concentration.

What is hypopolarization?

a situation in which the membrane of a cell has been reset to a more positive number than normal, shortening the polar gap status and making them more sensitive.

Example: a normal RMP is -90mV. Now the patient is hyperkalemic and their RMP is -60mV

Examples of states in which cells have become hypopolarized:

hyperkalemia, hypernatremia, hypocalcemia

What is hyperpolarization?

a situation in which the membrane of a cell has been reset to a less positive number than normal, lengthening the polar gap status and making them less sensitive.

Example: a normal RMP is -90mV. Now the patient is hypokalemic and their RMP is -120mV

Examples of states in which cells have become hyperpolarized:

hypokalemia, hyponatremia, hypercalcemia

If a patient's muscle cell is _________ then it will be twitchy, irritable, quick to spasm, and hyperactive.

hypopolarized

If a patient's muscle cell is _________ then it will be moving slower than normal or experiencing fatigue.

hyperpolarized

What is tetany?

severe, unrelenting muscle spasms

What is bradycardia?

a slower than normal heart rate (less than 60 beats per minute)

Hypocalcemia causes what special effect to the cell membrane with respect to sodium?

Low levels of calcium triggers an increase in the permeability of cell membranes to sodium, allowing more sodium into the cell than normal.

Low Ca levels = high Na levels in the cell = increased positivity inside the cell = hypopolarization.

What are the two main types of acidosis?

metabolic acidosis and respiratory acidosis

What are some typical causes of metabolic acidosis?

hypoxia, kidney failure, diabetic ketoacidosis, poison ingestion, drug overdose, excessive alcohol use.

How does the body compensate for metabolic acidosis?

The lungs will try to decrease the amount of acid /acid gang that is in the body by increasing the amount of CO2 that is exhaled. This is done by increasing rate and / or depth of breathing.

What are some typical causes of respiratory acidosis?

diminished effectiveness of breathing or a decreased respiratory rate (more on this in the pulmonary lecture)

How does the body compensate for respiratory acidosis?

Compensation is by the kidneys. HCO3 will be increased to buffer the situation / counteract the acid (CO2) that has accumulated from poor ventilation.

What are the two main types of alkalosis?

metabolic alkalosis and respiratory alkalosis

What are some typical causes of metabolic alkalosis?

a large amount of vomiting or an over-ingestion of bicarbonate

How does the body compensate for metabolic alkalosis?

Compensation is via the lungs, by decreasing the rate and depth of respirations.

What are some typical causes of respiratory alkalosis?

anxiety, fear, hyperventilation

How does the body compensate for respiratory alkalosis?

Compensation is by the kidneys, by decreasing the amount of HCO3 made or increasing its excretion.

What is osmosis?

The shifting of water from one fluid compartment to another via a semi-permeable membrane. Water will always want to move from an area with a lesser concentration of solutes to an area with a greater concentration of solutes. "Concentration calls!"

What is osmolality?

A measurement of how concentrated a compartment is (the proportion of solutes-to-water that is in a compartment's fluid).

Clinically we can measure the solute concentration of the blood by doing a serum osmolality and have an idea about what fluid shifts to anticipate since osmolality (concentration) rules osmosis.

What is tonicity?

the "saltiness" of a fluid or how much of it is made of salt. This is interchangeable with the term salinity. The normal tonicity (salinity) of the blood is 0.9%

Normal saline or NS or 0.9%NaCl

An IV fluid that has the same tonicity / salinity as blood.

0.45% NaCl or 0.45NS

An IV fluid that is hypotonic, or has a lower tonicity / salinity than blood.

3% NaCl or 3%NS

An IV fluid that is hypertonic when compared to the tonicity / salinity of blood. It is rarely used.

What is osmotic pressure?

The pressure exerted by all of the solutes in a compartment. It correlates with osmolality. Remember, concentration calls!

What is oncotic pressure?

The pressure exerted specifically by protein molecules in a compartment. It correlates with osmolality, and is also known as colloidal osmotic pressure. Remember, concentration calls!

What are some common causes for pathologic water loss?

inadequate intake (patient too sick to drink)

increased output (vomiting, diarrhea, increased urination)

end result: dehydration or fluid volume deficit

What are common symptoms of dehydration or fluid volume deficit?

dry mucuous membranes, poor skin turgor, sunken eyes, sunken fontanels in babies, oliguria, increased urine concentration, low BP, acute CNS changes, high serum osmolality.

Which body systems compensate for fluid volume deficit?

RAAS and ADH secretion

How does the RAAS work in patients with fluid volume deficit?

Kidneys secrete renin which stimulates the secretion of angiotensin I. Angiotension I is converted into angiotension II with the help of angiotension converting enzyme (ACE). Angiotension II causes peripherial vasoconstriction (to help with perfusion of central organs) and the release of aldosterone (which causes kidney tubules to hold onto Na and water).

How does ADH work in patients with fluid volume deficit?

Antidiuretic hormone is secreted by the pituitary gland and works on the tubules encouraging them to retain NA and water, decreasing urinary output.

What are some common causes for decreased blood concentration?

Any situation where pathologic water gain or solute / protein loss can occur.

End result: excess water or fluid volume overload (edema)

Describe some examples of pathologic water gain:

excess intake such as water intoxication

too much IV fluid

low output like kidney failure

hormonal problems like SIADH

Identify three causes of hypoproteinemia

diminished protein production such as found in certain types of liver diseases.

diminished protein intake / malnutrition

plasma protein loss such as is found in certain types of kidney diseases.

A patient with hypoproteinemia will look dehydrated or edematous?

edematous

A B to T fluid shift will make the patient appear to be in fluid volume _____________.

overload

Edema can be found in what parts of the body?

under the skin (skin appears tight and puffy), in the lung tissue (cough, crackles, SOB), in the brain cells (restlessness, confusion, unconsciousness, convulsions), and in the abdominal cavity (abdominal distension).

What compensatory mechanism corrects fluid overload?

The naturetic peptide system (NPS).

How does the NPS work?

The right atrium and left ventricle can detect when there is too much circulating volume. They secrete ANP and BNP into circulation which travels to the kidneys and stimulate them to increase urination. When fluid volume drops, this system is suppressed.