1. 생리학 ( 生理學, Physiology) General Physiology Organ Physiology Integrative Physiology Physics (Physical Chemistry, Biophysics)

2. Claude Bernard: 내환경의 항상성 (Homeostasis) ----- 온도, 삼투압, pH, 세포외액의 조성을 일정하게 유지하는 기능을 중요시.

3. 세포

4. Common molecular mechanisms in all forms of life Store genetic information in nucleic acids Employ proteins to catalyze chemical reactions Synthesize proteins on ribosomes Drive energy by breaking down simple sugars Use ATP as energy currency Separate cytoplasm from their environment by means of phospholipid membranes containing pumps, carriers, and channels

5. 세포막 Davson-Danielli 모델 : 두겹의 지방층 안팎으로 연속 적인 단백질층. Singer-Nicolson 모델 : 구형단백질이 인지질에 끼어 있는 lipid-globular protein mosaic model. 2003 년 : 세포막 단백질들의 다양한 기능과 구조가 밝혀져 가고 있음.

6. Membrane proteins Receptors Enzymes Transporters: pump, carrier, ion channels

7. 세포막을 통한 물질이동 Homeostasis 유지 Electrical signalling (membrane potential)

8. Membrane Lipid 기능 framework of biological membrane cell signalling: hormone, second messenger 전기적 특성 : 높은 절연성, 축전능 (1  F/cm 2 ) – 막전압 발생 가능 종류 Phosphoglycerides Sphingolipids Cholesterol Glycolipids

9. Phosphoglycerides (phospholipids) 구성 3-carbon backbone of glycerol 2 long-chain fatty acids esterified to C1 and C2 phosphoric acid esterified to C3 분류 : Alcohol head group 에 따라. Phosphatidylethanolamine Phosphatidylcholine Phosphatidylserine phosphatidylinositol

10. Lipid asymmetry

11. Intercellular Junctions 4 types, each composed of a different transmembrane protein, connect the plasma membrane of adjacent cells

12. Molecular components of cell-cell and cell-matrix junctions

13. Adherens junctions and desmosomes Adherens junctions (zonula adherens) : cadherins anchored to actin filaments. Desmosomes (macular adherens) : cadherins anchored to intermediate filaments.

14. Tight junctions (zonula occludens) Occlude the extracellular space between epithelial cells, forming a tight, belt-like seal that limits diffusion of water, ions, and solutes (larger than 1.8 nm).

15. Tight junctions Tightness of the seal, reflected in electrial resistance, varies depending on cell type (extremely tight in frog skin; leaky in blood vessel); regulated by hormones (ADH, cytokines). Define the boundary between apical and basolateral membranes: two surfaces differ in lipid and protein compositions and functions.

16. Gap junctions Two ways of intercellular communications: 1) by secreting chemical messengers; 2) direct communication by gap jucntion (electrical synapse). Connexins: proteins with 4 transmembrane  helices Connexon: half channel in each membrane, made by lateral association of 6 connexins Each connexon pairs with a connexon from the adjacent cell, forming a gap junction

17. Gap junction channels 10 nm long/1,2 nm diameter; size filter up to 1kD pass ions to establish electrochemical continuity (electrical synapse); second messengers to establish common network of information; and metabolites to allow sharing of resources Conductance: 30 to 300 pS Open/close is regulated by transjunctional potential, cytoplasmic Ca 2+, pH, cAMP- protein kinase. Gap junction closing -- terminates communication with neighboring cells that are damaged or metabolically compromised.

18. Body Fluid Compartment 모세혈관을 통한 물질이동 세포막을 통한 물질이동