生理学第二章 细胞
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Gate mechanism: voltage, ligand and mechanic Cation: K+,Na+,Ca2+ Negion: ClAquaporin: water
Carriers
Specific
Competive inhibition
Saturable
3. Active transport
Patch clamp recording
Suction
Glass microelectrode
1 µm
"Giga-seal"
P
Threshold stimulus
P0 T0 Intensity-duration curve T
2.Measurement of cell bioelectricity:
Extracellular record; Microelectrode and Intracellular record;
Part 2. Trans-membrane signal transduction
Part 3. Cellular bioelectricity
Part 4. Contraction of muscle cell
Part Ⅰ: Transport across cell membrane
Essential role of cell membrane:
Secondary active transport
co-transport (symport) counter-transport (antiport) out Na+ in
out
Na+
in
glucose
Co-transporters will move one moiety, e.g. glucose, in the same direction as the Na+.
Exocytosis
Vesicle containing the secretory protein fuses with plasma membrane, to remove contents from cell.
Endocytosis
Material enters the cell through the plasma membrane within vesicles.
H+
Counter-transporters will move one moiety, e.g. H+, in the opposite direction to the Na+.
Out side higher sodium and lower glucose
Inside lower sodium and higher glucose
Signal across membrane transduction based on the receptor-G protein-effect enzyme system and induction of the second messages.
Part 3. Cellular Bioelectricity
The Nobel Prize in Physiology or Medicine (1991)
Erwin Neher
Bert Sakmann
"for their discoveries concerning the function of single ion channels in cells"
2. Facilitated diffusion
Definition: the substances which are insoluble in lipids pass
through the cell membrane down it’s gradient by the help of
membrane proteins. Character: ①down gradient either chemical or electrical ; ②specific ; ③adjustable .
生理学 第2章
细胞
cells
秦晓群 qinxiaoqun@ 中南大学湘雅医学院生理学系
General Functions Cells
Cellular Basic of Physiologic Function
Xiaoqun Qin, PhD.,MD.
Outline
Part 1. Transport across cell membrane
Directional transport Coupling process ATP is directly required Electrogenic process
Importance of the
+ + Na -K
Pump
Maintain high intracellular K+ concentration gradients across the membrane. Control cell volume and phase Maintain normal pH inside cell Develop and Maintain Na+ and K+ concentration gradients across the membrane Electrogenic action influences membrane potential Provides energy for secondary active transport
Secondary Active Transport
Coupled transport. Energy needed for ―uphill‖ movement obtained from ―downhill‖ transport of Na+. Hydrolysis of ATP by Na+/K+ pump required indirectly to maintain [Na+] gradient.
Voltage clamp and patch clamp
The Nobel Prize in Physiology or Medicine (1963)
Alan Lloyd Hodgkin
Andrew Fielding Huxley
“for their discoveries concerning the ionic mechanisms involved in excitation and inhibition in the peripheral and central portions of the nerve cell membrane”
• • • • • Action of outpost Exchange of material Accept signal Distinguish mark Programming reactions
1. Simple diffusion
D
D = k×△C
C
Model of simple diffusion
The voltage clamp
Cole and colleagues developed a method for maintaining Vm at any desired voltage level (FBA, Feedback Amplifier) Required monitoring voltage changes, feeding it through an amplifier to drive current into or out of the cell to dynamically maintain the voltage while recording the current required to do so
Types of Endocytosis
Phagocytosis - (―cellular eating‖) cell engulfs a particle and packages it with a food vacuole. Pinocytosis – (―cellular drinking‖) cell gulps droplets of fluid by forming tiny vesicles. (unspecific) Receptor-Mediated – binding of external molecules to specific receptor proteins in the plasma membrane. (specific)
Character: using ATP; against gradient.
Significance: reserving potential; protect cell from swollen.
3 Na+ 2 K+ ATP ADP+Pi
Characteristics of the Transport + by Na pump
4.Bulk Transport (Endocytosis and Excytosis)
Movement of many large molecules, that cannot be transported by carriers. Exocytosis: A process in which some large particles move from inside to outside of the cell by a specialized function of the cell membrane Endocytosis: Exocytosis in reverse. Specific molecules can be taken into the cell because of the interaction of the molecule and protein receptor.
1.Conception about stimulus and excitability
• Excitation: an action potential occurs after a effective stimulus acting on cell. • Excitability: cell’s ability to genesis action potential after being stimulated. • Excitable cells: cells which are easy to genesis action potential under stimulus. • Essential element of stimulus: intensity ,duration,changing rate.
Types:
(1)channel mediated diffusion (2)carrier mediated diffusion.
Ion channels
Across membrane aqueous pore formed in the inner of a trans-membrane proteins, which permits ions or water molecules pass through.
Example of Receptor-Mediated Endocytosis in human cells
Part 2. Trans-membrane signal transduction
• Receptor-gated channel • Receptor-GTP binding protein-effecter enzyme system: CA→cAMP; CG →cGMP; PLC →IP3,DG • Tyrosine protein kinase (TPK) receptor
Carriers
Specific
Competive inhibition
Saturable
3. Active transport
Patch clamp recording
Suction
Glass microelectrode
1 µm
"Giga-seal"
P
Threshold stimulus
P0 T0 Intensity-duration curve T
2.Measurement of cell bioelectricity:
Extracellular record; Microelectrode and Intracellular record;
Part 2. Trans-membrane signal transduction
Part 3. Cellular bioelectricity
Part 4. Contraction of muscle cell
Part Ⅰ: Transport across cell membrane
Essential role of cell membrane:
Secondary active transport
co-transport (symport) counter-transport (antiport) out Na+ in
out
Na+
in
glucose
Co-transporters will move one moiety, e.g. glucose, in the same direction as the Na+.
Exocytosis
Vesicle containing the secretory protein fuses with plasma membrane, to remove contents from cell.
Endocytosis
Material enters the cell through the plasma membrane within vesicles.
H+
Counter-transporters will move one moiety, e.g. H+, in the opposite direction to the Na+.
Out side higher sodium and lower glucose
Inside lower sodium and higher glucose
Signal across membrane transduction based on the receptor-G protein-effect enzyme system and induction of the second messages.
Part 3. Cellular Bioelectricity
The Nobel Prize in Physiology or Medicine (1991)
Erwin Neher
Bert Sakmann
"for their discoveries concerning the function of single ion channels in cells"
2. Facilitated diffusion
Definition: the substances which are insoluble in lipids pass
through the cell membrane down it’s gradient by the help of
membrane proteins. Character: ①down gradient either chemical or electrical ; ②specific ; ③adjustable .
生理学 第2章
细胞
cells
秦晓群 qinxiaoqun@ 中南大学湘雅医学院生理学系
General Functions Cells
Cellular Basic of Physiologic Function
Xiaoqun Qin, PhD.,MD.
Outline
Part 1. Transport across cell membrane
Directional transport Coupling process ATP is directly required Electrogenic process
Importance of the
+ + Na -K
Pump
Maintain high intracellular K+ concentration gradients across the membrane. Control cell volume and phase Maintain normal pH inside cell Develop and Maintain Na+ and K+ concentration gradients across the membrane Electrogenic action influences membrane potential Provides energy for secondary active transport
Secondary Active Transport
Coupled transport. Energy needed for ―uphill‖ movement obtained from ―downhill‖ transport of Na+. Hydrolysis of ATP by Na+/K+ pump required indirectly to maintain [Na+] gradient.
Voltage clamp and patch clamp
The Nobel Prize in Physiology or Medicine (1963)
Alan Lloyd Hodgkin
Andrew Fielding Huxley
“for their discoveries concerning the ionic mechanisms involved in excitation and inhibition in the peripheral and central portions of the nerve cell membrane”
• • • • • Action of outpost Exchange of material Accept signal Distinguish mark Programming reactions
1. Simple diffusion
D
D = k×△C
C
Model of simple diffusion
The voltage clamp
Cole and colleagues developed a method for maintaining Vm at any desired voltage level (FBA, Feedback Amplifier) Required monitoring voltage changes, feeding it through an amplifier to drive current into or out of the cell to dynamically maintain the voltage while recording the current required to do so
Types of Endocytosis
Phagocytosis - (―cellular eating‖) cell engulfs a particle and packages it with a food vacuole. Pinocytosis – (―cellular drinking‖) cell gulps droplets of fluid by forming tiny vesicles. (unspecific) Receptor-Mediated – binding of external molecules to specific receptor proteins in the plasma membrane. (specific)
Character: using ATP; against gradient.
Significance: reserving potential; protect cell from swollen.
3 Na+ 2 K+ ATP ADP+Pi
Characteristics of the Transport + by Na pump
4.Bulk Transport (Endocytosis and Excytosis)
Movement of many large molecules, that cannot be transported by carriers. Exocytosis: A process in which some large particles move from inside to outside of the cell by a specialized function of the cell membrane Endocytosis: Exocytosis in reverse. Specific molecules can be taken into the cell because of the interaction of the molecule and protein receptor.
1.Conception about stimulus and excitability
• Excitation: an action potential occurs after a effective stimulus acting on cell. • Excitability: cell’s ability to genesis action potential after being stimulated. • Excitable cells: cells which are easy to genesis action potential under stimulus. • Essential element of stimulus: intensity ,duration,changing rate.
Types:
(1)channel mediated diffusion (2)carrier mediated diffusion.
Ion channels
Across membrane aqueous pore formed in the inner of a trans-membrane proteins, which permits ions or water molecules pass through.
Example of Receptor-Mediated Endocytosis in human cells
Part 2. Trans-membrane signal transduction
• Receptor-gated channel • Receptor-GTP binding protein-effecter enzyme system: CA→cAMP; CG →cGMP; PLC →IP3,DG • Tyrosine protein kinase (TPK) receptor