General physiology (powerpoint) - DONE Flashcards
(27 cards)
Homeostasis means?
Homeostasis means capability to regulate parameters of the internal environment.
Proteostasis of the cells:
- role of gene expression
- protein-protein interaction (posttranslatory modification as a shorter method of protein function regulation).
Basic cellular organs:
- nucleus
- endoplasmic reticulum
- golgi apparatus
- ribosomes
- miochondria
- lysosomes
- peroxisomes
- proteasomes
- storage vesicles
Osmotic pressure
The pressure acting on the membrane, related to volume imbalance on both sides of the membrane, is called osmotic pressure.
Osmole
Osmole is a substance solved in water, to which cell membrane is impermeable while being at the same time permeable to water
Osmolality, or “osmotic strength” of a solution:
Osmolality, or “osmotic strength” of a solution is a concentration of all osmoses combined (in moles per 1 kg of water).
Most osmoses may include:
- electrolytes
- glucose
- other carbohydrates
- proteins
Hypoosmotic enviroment
In hypoosmotic enviroment, there is a tendency to entry of water into the cell, which can increase cell volume and - in extreme cases - rupture the cell membrane
Hyperosmotic =
of smaller concentration of water (i.e. greater concentration of osmoles, greater osmolality)
Significance of ion channels:
- for cell excitability
- for resting potential
- many differences in composition between ICF vs ECF.
Cell membrane proteins:
- ion channels
- receptors
- intercellular adhesion molecules
- carrier proteins for facilitated diffusion
- symporter and antiporter proteins
- primary active transporters
- aquaporins
Osmosis
Diffusion of water down its concentration gradient whenever the cell membrane is impermeable for solutes
Solutes
substances dissolved in that water
Simple diffusion
- refers to substances, to which cell membranes are unconditionally permeable (lipid-soluble substances)
- examples of such substances include: oxygen, carbon dioxide, steroid hormones.
Facilitated diffusion =
Carrier-mediated transport
Facilitated diffusion (carrier-mediated transport):
read about it slide #15
Secondary active transport:
- transports substances against their concentration gradient
- does not use ATP directly
- but uses sodium concentration gradient (created by ATPases) as a driving force
- symport or antiport
It is called symport when:
all substances are transported in the same direction (e.g. glucose + sodium into the cell)
It is called antiport (or exchanger):
if not all substances are transported in the same direction (e.g. sodium/calcium exchanger in the heart muscle cells)
Primary active transport
- require energy use (ATP)
- transports substances against their concentration gradient
Example of primary active transport and how it works:
sodium-potassium pump:
- its activity accounts for differences of ion concentration in ICF vs ECF
- its activity contributes to resting potential of cell membranes (because it´s electrogenic)
- its activity allows secondary active transport by generating sodium concentration gradient (through cell membrane) as a driving force for secondary active transport.
ICF=
intracellular fluid
ECF=
extracellular fluid
Read about
slide 1-9
