physiology + histology summary Flashcards
(46 cards)
membrane components
phospholipid bilayer
cholesterol
proteins
carbohydrates
Cholesterol –
for fluidity, stability, stiffness
Proteins –
transport proteins, enzymes, receptors, cell adhesion molecules
Carbohydrates –
exterior – self-identity markers enabling cells to interact
Desmosomes –
adhering junctions that anchor cells together [anchoring junctions]
Tight junctions –
join lateral edges of epithelial cells [occluding junctions]
Gap junctions –
movement of molecules between cells [communicating j…]
Cation =
positively charged ion
Anion =
negatively charged ion Fick’s law
Electrochemical gradient –
electrical and chemical forces act on ion at same time to form gradient
Isotonic =
conc of solute equal in / out cell
Hypertonic =
conc solute outside cell > conc inside cell [hypotonic opposite]
Hypertonic solution –
cell shrinks
Facillated diffusion –
no energy, carrier mediated, high > low conc
Primary active transport –
energy directly required
Secondary active transport –
energy stored in form of ion concentration gradient
Symport –
co-transport [same direction]
Antiport –
exchange / counter-transport [opposite directions]
Na+/K+-ATPase:
primary active transport, 2 K+ in / 3 Na+ out [both against conc gradient]
- Establishes Na+ and K+conc gradient
- Used as energy source for secondary active transport
Endocytosis –
membrane pinches off and engulfs substances inside cell [phagocytosis]
Exocytosis –
cell transports molecules out of cell
Nerve cell resting membrane potential =
-70mV
Ek =
-90mV
ENa =
+60mV