Tonicity, Calcium Homeostasis Flashcards
Homeostasis
The normal conditions under which the body systems operate. Must be maintained for survival
What is the blood pH
7.35-7.45, A drop in this pH range can be life threatening.
Fluids comportments
Blood, Plasma, Intracellular, Extracellular, interstitial(tissue). All have different concentrations of ions and proteins within them.
What happens to the pH when the H ion concentration increases or decrease
As H ions increase, the pH decreases and becomes acidic.
As H ions decrease, the pH increases and becomes basic.
What is a buffer?
A buffer has the ability to bind or release H ions in solution to maintain the pH range.
Compare and Contrast Acidosis & Alkalosis
They are both disorders that happen with the excess of acid or base which leads to the failure to remove CO2 and intake O2.
Respiratory Acidosis & Alkalosis
They are issues with excess acid or base due to respiratory failure or ventilation failure in the case of acidosis. Respiratory alkalosis is due to alveolar hyperventilation.
Metabolic acidosis or alkalosis
Can be caused by anything that disrupts the body’s metabolism. Electrolytic disturbances, severe vomiting or diarrhea.
What is the Bicarb Equation
CO2 + H20 EQ H2CO3 EQ H + HCO3
As CO2 leaves, H rushes towards the left and H will decrease and make the solution less acidic.
Failure to remove CO2 makes the solution more acidic due to the H ion still being present.
Treatment for acidosis
Using bicarb is an effective treatment because as you release CO2 you can shift the H concentration to the left which decreases the excess acid concentration and it also helps the lungs release more CO2.
Sodium Potassium Pump
Sodium rushes in ( high outside, low inside)
Potassium wants to stay in (high inside, low outside)
Osmosis & Osmotic pressure
Osmosis is the movement of water across the membrane to restore eq.
Water moves towards the more concentrated area because it has less water.
Osmotic pressure is the force needed to stop water from performing osmosis.
Osmolarity
Osmolarity is the measure of the number of particles per liter of solution. It has to be relative to something else. A to B or B to A.
Make sure to check the units!
Iso-osmotic vs Hyposomotic vs Hyperosmotic
Iso-osmotic when concentrations are equal.
Hyposomotic when the concentration is lower than what is being compared to.
Hyperosmotic when the concentration is higher than what is being compared to.
Osmolarity of NaCl
NaCl will dissociate meaning that for 1 osmole we have 2 molecules ( 1 Na and 1 Cl)
If given molarity, must be converted to osmoles.
Tonicity & Non-penetration solutes
Concentration of non-penetrating solutes.
NaCl is non-penetrating
3 solutes to know
NaCl- Non-penetrating Ions
Urea- Freely penetrates the membrane
Glucose- crosses the membrane but then is consumed for glycolysis.
Rules for osmolarity & tonicity
1- Intracellular solutes are non-penetrating.
2- Determine osmolarity.
3-Recalculate the new volume concentrations.
4-Determine tonicity.
5-Hyposmotic solutions are always hypotonic.
Channel Proteins vs Carrier Proteins
Channel proteins open or close; once open molecules diffuse through with no restrictions.
Carrier proteins have a transport limit when letting molecules in. There is a set amount of particles that can enter at one time.
Primary Active transport vs Secondary Active transport
Primary active transport moves things against their concentration gradient and therefore requires ATP, Sodium being pushed out of the cell.
Secondary Active transport moves things using the potential energy of the gradient. No ATP is required because it follows the regular concentration gradient. As sodium rushes into the cell, glucose also enters the cell.
Membrane equilibrium
It is determined by both the electrical and chemical gradients, the membrane resting potential is -70 mV and the concentration of intracellular potassium determines that.
Potassium Efflux vs Influx
Potassium Efflux makes it want to flow out of the cell by following its concentration gradient.
Potassium influx into the cell because of the electrical gradient pulling the K + into the cell.
They are both in equilibrium with each other.
Calcium Homeostasis
Requires both connective and epithelial tissues like the bones and glands.
What is calcitonin’s relationship to Blood calcium and Bones
Calcitonin takes calcium out of the blood and pushes it into the bones with the help of osteoblasts ( build bones and store calcium).
What is PTH relationship to Blood calcium, Bones and the kidney
Parathyroid hormone (PTH) takes calcium out of the bones with the help of osteoclasts ( release acid to break down bones and release calcium) through bone resorption. It increases calcium in the kidney. Also help with vitamin D synthesis. Targets the gut and release calcium in blood.
Vitamin D synthesis and skin color
Skin color is due to variation of MC1R which produces eumelanin and pheomelanin.
Eumelanin vs Pheomelanin
Eumelanin produces dark and brown skin color, it also helps protect the nucleus from UV light by acting as a barrier.
Pheomelanin produces pales skin colors.
Skin color and vitamin D synthesis
Vitamin D production is proportional to light penetration. Pheomelanin lets light into the body and vitamin D however eumelanin acts as a barrier and therefore requires a high light intensity to penetrate the cell.
Vitamin D synthesis and Calcitriol
Calcitriol is vitamin D modified by the kidney and liver, which means that people with pheomelanin are better at producing calcitriol due to better light penetration but people with eumelanin have a harder time producing calcitriol as the eumelanin acts as a barrier to protect the nucleus.
Folate Breakdown and UV light
Folate which is vitamin B starts to break down when exposed to a high level of UV exposure. When people with high levels of pheomelanin at low latitudes are exposed to UV light, their folates break down. People with high levels of eumelanin can preserve their folate as the eumelanin protects them from UV exposure.
Folate insufficiency
It can lead to neural defects during child development such as spina bifida (unclosed vertebrae).
Chloasma
an increase in melanin production during pregnancy and it’s most likely to protect folate.
Vitamin D deficiency
High levels of eumelanin at high latitudes can cause vitamin D deficiencies like rickets which is the deformation of long bones when babies start to walk.
