Cellular Calcium Homeostasis Flashcards
How is whole body calcium regulated?
- Intestinal calcium uptake
- Calcium reabsorption in kidneys
- Bone calcium regulation
Name 2 ways calcium is controlled by endocrine pathways
- Calcium receptors in Parathyroid gland
- Parathyroid hormone
- Vitamin D
- Calcitonin
Where is Calcium most abundant intracellularly?
- Low in cytoplasm
- Most in endoplasmic reticulum
- Large amount extracellularly
Name 3 bodily processes that involve calcium gradients
- Muscle contraction
- Neurotransmission
- Fertilisation
- Cell death
- Metabolism regulation
- Learning and memory
What 3 cell processes regulate calcium concentration gradients?
- Plasma membrane impermeability
- Calcium pumps and transporters
- Calcium buffer proteins
How can calcium levels be increased by the cell?
- Voltage operated calcium channels
- Ligand gated Ion Channels
- Movement out of ER using receptor pathways
Which calcium transporters move calcium into the cell?
VOCC (Voltage Operated Calcium Channel)
CICR (Calcium Induced Calcium Release)
Which 3 transporter mechanisms move calcium out of the cell?
PMCA (Plasma Membrane Ca2+ ATPase)
SERCA (Sarco/Endoplasmic Reticulum Ca2+ ATPase)
NCX (Sodium-Calcium Exchange)
Explain the action of PMCA in moving calcium out of the cell
Uses ATP to move calcium from the cytoplasm to outside of the cell
How does SERCA reduce calcium content in the cytoplasm?
Moves calcium from the cytoplasm to calcium stores in the endoplasmic reticulum
How does NCX move calcium out of the cell and what other pump system is it reliant on?
- Facilitated diffusion moves Na+ into the cell and Ca2+ out of the cell
- Needs energy to move against the gradient
- Dependent on Na+/K+ pump to maintain extracellular Na+ levels
