Cellular Physiology; Mosby's Physiology Monograph Series

by Blaustein, Kao & Matteson

• ISBN13: 9780323013413
• ISBN10: 0323013414
• Edition: 1st
• Format: Paperback
• Copyright: 2004-06-24
• Publisher: Mosby

Summary

This one-of-a-kind text bridges the gap between basic biochemistry, molecular and cell biology, and organ and systems physiologyproviding rich, clinically oriented coverage of the subject. It presents information in an intuitive, user-friendly fashion, continually emphasizing how cell biology concepts apply to physiological processes. Uses discussions of molecular mechanisms to lay a foundation for understanding therapeutic interventions. Provides frequent examples from systems physiology, pharmacology, and pathophysiology to underscore the clinical implications of the material. Includes discussions of recently discovered molecular mechanisms to offer an up-to-date grasp of the field. Offers comprehensive discussions of transport processeswhich are integral to all physiological processes, yet are neglected in many other cell biology texts. Sets mathematical derivations apart in special boxes, so they do not interrupt the flow of the text but are available for reading if desired. Features an extensive appendix that includes multiple-choice review questions with answers, a review of mathematical techniques, and a summary of basic circuit theory.

Table of Contents

Fundamental Physicochemical Concepts
Introduction: Homeostasis and Cellular Physiology	p. 1
Homeostasis enables the body to survive in diverse environments	p. 1
The body is an ensemble of functionally and spatially distinct compartments	p. 2
Transport processes are essential to physiological function	p. 4
Cellular physiology focuses on membrane-mediated processes and on muscle function	p. 5
Summary	p. 5
Key words and concepts	p. 6
Diffusion and Permeability	p. 7
Diffusion is the migration of molecules down a concentration gradient	p. 7
Fick's First Law of Diffusion summarizes our intuitive understanding of diffusion	p. 7
Essential aspects of diffusion are revealed by quantitive examination of random, microscopic movements of molecules	p. 9
Fick's First Law can be used to describe diffusion across a membrane barrier	p. 12
Summary	p. 20
Key words and concepts	p. 20
Study problems	p. 20
Osmotic Pressure and Water Movement	p. 21
Osmosis is the transport of solvent driven by a difference in solute concentration across a membrane that is impermeable to solute	p. 21
Water transport during osmosis leads to changes in volume	p. 22
Osmotic pressure drives the net transport of water during osmosis	p. 22
Osmotic pressure and hydrostatic pressure are functionally equivalent in their ability to drive water movement through a membrane	p. 25
Only impermeant solutes can have permanent osmotic effects	p. 30
Summary	p. 32
Key words and concepts	p. 35
Study problems	p. 35
Electrical Consequences of Ionic Gradients	p. 37
Ions are typically present at different concentrations on opposite sides of a biomembrane	p. 37
Selective ionic permeability through membranes has electrical consequences: the Nernst equation	p. 37
The stable resting membrane potential in a living cell is established by balancing multiple ionic fluxes	p. 42
The cell can change its membrane potential by selectively changing membrane permeability to certain ions	p. 48
The Donnan effect is an osmotic threat to living cells	p. 48
Summary	p. 49
Key words and concepts	p. 52
Study problems	p. 52
Ion Channels and Excitable Membranes
Ion Channels	p. 53
Ion channels are critical determinants of the electrical behavior of membranes	p. 53
Distinct types of ion channels have several common properties	p. 54
Ion channels share structural similarities and can be grouped into gene families	p. 56
Summary	p. 59
Key words and concepts	p. 61
Study problems	p. 61
Passive Electrical Properties of Membranes	p. 63
The time course and spread of membrane potential changes are predicted by the passive electrical properties of the membrane	p. 63
The equivalent circuit of an excitable membrane has a resistor in parallel with a capacitor	p. 64
Passive membrane properties produce linear current-voltage relationships	p. 65
Membrane capacitance affects the time course of voltage changes	p. 65
Membrane and axoplasmic resistances affect the passive spread of subthreshold electrical signals	p. 69
Summary	p. 73
Key words and concepts	p. 73
Study problems	p. 74
Generation and Propagation of the Action Potential	p. 75
The action potential is a rapid and transient depolarization of the membrane potential in electrically excitable cells	p. 75
Ion channel function is studied with a voltage clamp	p. 77
Individual ion channels have two conductance levels	p. 83
Sodium channels inactivate during maintained depolarization	p. 84
The action potential is generated by voltage-gated Na[superscript +] and K[superscript +] channels	p. 86
Action potential propagation occurs as a result of local circuit currents	p. 89
Summary	p. 96
Key words and concepts	p. 96
Study problems	p. 97
Ion Channel Diversity	p. 99
Various types of ion channels help to regulate cellular processes	p. 99
Voltage-gated Ca[superscript 2+] channels contribute to electrical activity and mediate Ca[superscript 2+] entry into cells	p. 99
Potassium-selective channels are the most diverse type of channel	p. 104
Ligand-gated channels are gated by agonist binding	p. 111
Ion channel activity can be regulated by second-messenger pathways	p. 113
Summary	p. 115
Key words and concepts	p. 115
Study problems	p. 116
Solute Transport
Electrochemical Potential Energy and Transport Processes	p. 117
Electrochemical potential energy drives all transport processes	p. 117
Summary	p. 126
Key words and concepts	p. 126
Study problems	p. 126
Passive Solute Transport	p. 127
Diffusion across biological membranes is limited by lipid solubility	p. 127
Channel, carrier, and pump proteins mediate transport across biological membranes	p. 128
Carriers are integral membrane proteins that open to only one side of the membrane at a time	p. 130
Coupling the transport of one solute to the "downhill" transport of another solute enables carriers to move the cotransported or countertransported solute "uphill" against an electrochemical gradient	p. 134
Sodium is cotransported with a variety of solutes such as glucose and amino acids	p. 136
Net transport of some solutes across epithelia is effected by coupling two transport processes in series	p. 139
Sodium is exchanged for solutes such as calcium and protons by countertransport mechanisms	p. 141
Multiple transport systems can be functionally coupled	p. 144
Summary	p. 146
Key words and concepts	p. 147
Study problems	p. 147
Active Transport	p. 149
Primary active transport converts the chemical energy from ATP into electrochemical potential energy stored in solute gradients	p. 149
The plasma membrane Na[superscript +] pump (Na, K-ATPase) maintains the low Na[superscript +] and high K[superscript +] concentrations in the cytosol	p. 150
Intracellular Ca[superscript 2+] signaling is universal and is closely tied to Ca[superscript 2+] homeostasis	p. 154
Ca[superscript 2+] storage in the sarcoplasmic/endoplasmic reticulum is mediated by a Ca[superscript 2+]-ATPase	p. 157
The plasma membrane of most cells also has an ATP-driven Ca[superscript 2+] pump	p. 158
Transport systems may be functionally coupled in parallel or in series	p. 160
Several other plasma membrane transport ATPases also play important physiological roles	p. 160
Net transport across epithelial cells depends on the coupling of apical and basolateral membrane transport systems	p. 165
Summary	p. 174
Key words and concepts	p. 175
Study problems	p. 175
Molecular Motors and Muscle Contraction
Molecular Motors and the Mechanisms of Muscle Contraction	p. 177
Molecular motors produce motility by converting chemical energy into kinetic energy	p. 177
Single skeletal muscle fibers are composed of many myofibrils	p. 178
The sarcomere is the basic unit of contraction in skeletal muscle	p. 178
According to the "sliding filament" mechanism, muscle contraction results from thin and thick filaments sliding past each other	p. 182
The cross-bridge cycle powers muscle contraction	p. 184
In skeletal and cardiac muscles, Ca[superscript 2+] activates contraction by binding to the regulatory protein troponin C	p. 188
The structure and function of cardiac muscle and smooth muscle-are distinctly different from those of skeletal muscle	p. 188
Summary	p. 196
Key words and concepts	p. 196
Study problems	p. 197
Excitation-Contraction Coupling in Muscle	p. 199
Skeletal muscle contraction is initiated by a depolarization of the surface membrane	p. 199
Direct mechanical interaction between sarcolemmal and sarcoplasmic reticulum membrane proteins may mediate excitation-contraction coupling in skeletal muscle	p. 202
Ca[superscript 2+]-induced Ca[superscript 2+] release is central to excitation-contraction coupling in cardiac muscle	p. 208
Activation of smooth muscle differs in fundamental ways from excitation-contraction coupling in skeletal and cardiac muscles	p. 211
Summary	p. 221
Key words and concepts	p. 222
Study problems	p. 222
Mechanics of Muscle Contraction	p. 225
The total force generated by a skeletal muscle can be varied by several mechanisms	p. 225
Skeletal muscle mechanics is characterized by two fundamental relationships	p. 229
There are three main types of phasic skeletal muscle motor units	p. 232
The force generated by cardiac muscle is regulated by various mechanisms that control [Ca superscript 2+ subscript i]	p. 234
The mechanical properties of cardiac and skeletal muscle are similar, but there are significant quantitative differences	p. 235
The dynamic properties of smooth muscle contraction differ markedly from those of skeletal and cardiac muscle	p. 238
Some properties of specific types of smooth muscles can be resolved by a study of individual myosin motors	p. 241
The relationship among [Ca superscript 2+ subscript i] concentration, myosin phosphorylation, and mechanical force in smooth muscles is complex	p. 242
Summary	p. 246
Key words and concepts	p. 249
Study problems	p. 249
Epilogue	p. 251
Appendixes
A Mathematical Refresher	p. 255
Exponents	p. 255
Logarithms	p. 257
Solving quadratic equations	p. 258
Differentiation and derivatives	p. 258
Integration: the antiderivative and the definite integral	p. 263
Differential equations	p. 264
Root-Mean-Squared Displacement of Diffusing Molecules	p. 267
Summary of Elementary Circuit Theory	p. 271
Cell membranes are modeled with electrical circuits	p. 271
Definitions of electrical parameters	p. 271
Current flow in simple circuits	p. 273
Answers to Study Problems	p. 281
Review Examination	p. 295
Answers to review examination	p. 309
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