XII Table of Contents integrative Systems of the Body..268 Humoral Signals: Control and Effects..274 ellular Transmission of Signals from Extracellular Messengers..276 tary System…282 Carbohydrate Metabolism and Pancreatic Hormones.. 284 Biosynthesis of Steroid Hormones..296 Adrenal Cortex and Glucocorticoid Synthesis..298 nesis and the Menstrual Cycle..300 Hormonal Control of the Menstrual Cycle 302 Estrogens, Progesterone .. 304 Hormonal Control of Pregnancy and Birth..306 Androgens and Testicular Function Sexual Response, Intercourse and Fertilization..310 12 Central Nervous System and Senses 312 312 Cerebrospinal Fluid.. 312 tumulus Reception and Processing Proprioception, Stretch Reflex Polysynaptic Reflexes..322 aptic Inhibition…322 Central Conduction of Sensory Input..324 Hypothalamus, Limbic System . 332 Cerebral Cortex, Electroencephalogram(EEG)..334 Circadian Rhythms, Sleep-Wake Cycle. 336 Consciousness, Sleep. 338 44 Sense of smell….346 48 Optical Apparatus of the Eye..352 isual Acuity, Photosensors..35 daptation of the Eye to Different Light Intensities.. 358 Retinal Processing of visual Stimuli Color vision…362 Visual Field, Visual Pathway, Central Processing of Visual Stimuli.. 364 Physical Principles of Sound-Sound Stimulus and Perception-.36 Conduction of Sound, Sound Sensors.. 370
XII 11 Hormones and Reproduction 268 Integrative Systems of the Body · · · 268 Hormones · · · 270 Humoral Signals: Control and Effects · · · 274 Cellular Transmission of Signals from Extracellular Messengers · · · 276 Hypothalamic–Pituitary System · · · 282 Carbohydrate Metabolism and Pancreatic Hormones · · · 284 Thyroid Hormones · · · 288 Calcium and Phosphate Metabolism · · · 292 Biosynthesis of Steroid Hormones · · · 296 Adrenal Cortex and Glucocorticoid Synthesis · · · 298 Oogenesis and the Menstrual Cycle · · · 300 Hormonal Control of the Menstrual Cycle · · · 302 Estrogens, Progesterone · · · 304 Progesterone, Prolactin, Oxytocin · · · 305 Hormonal Control of Pregnancy and Birth · · · 306 Androgens and Testicular Function · · · 308 Sexual Response, Intercourse and Fertilization · · · 310 12 Central Nervous System and Senses 312 Central Nervous System · · · 312 Cerebrospinal Fluid · · · 312 Stimulus Reception and Processing · · · 314 Sensory Functions of the Skin · · · 316 Proprioception, Stretch Reflex · · · 318 Nociception and Pain · · · 320 Polysynaptic Reflexes · · · 322 Synaptic Inhibition · · · 322 Central Conduction of Sensory Input · · · 324 Movement · · · 326 Hypothalamus, Limbic System · · · 332 Cerebral Cortex, Electroencephalogram (EEG) · · · 334 Circadian Rhythms, Sleep–Wake Cycle · · · 336 Consciousness, Sleep · · · 338 Learning, Memory, Language · · · 340 Glia · · · 344 Sense of Taste · · · 344 Sense of Smell · · · 346 Sense of Balance · · · 348 Eye Structure, Tear Fluid, Aqueous Humor · · · 350 Optical Apparatus of the Eye · · · 352 Visual Acuity, Photosensors · · · 354 Adaptation of the Eye to Different Light Intensities · · · 358 Retinal Processing of Visual Stimuli · · · 360 Color Vision · · · 362 Visual Field, Visual Pathway, Central Processing of Visual Stimuli · · · 364 Eye Movements, Stereoscopic Vision, Depth Perception · · · 366 Physical Principles of Sound—Sound Stimulus and Perception · · · 368 Conduction of Sound, Sound Sensors · · · 370 Table of Contents
Table of Contents XIll ral Processing of Acoustic Information . 374 and s 3 Dimensions and Units. 378 esentation of data…38 Important Equations in Physiology..394 Further Reading Index
XIII Central Processing of Acoustic Information · · · 374 Voice and Speech · · · 376 13 Appendix 378 Dimensions and Units · · · 378 Powers and Logarithms · · · 386 Logarithms, Graphic Representation of Data · · · 387 Reference Values in Physiology · · · 390 Important Equations in Physiology · · · 394 Further Reading 397 Index 399 Table of Contents
Color atlas of Physiology 6th edition
III Color Atlas of Physiology 6th edition
2 The body: an Open System with an Internal Environment ". If we break up a living organism by isolating its different parts, it is only analysis and by no means in orderi eive them separately. Indeed, when we wish to ascribe to a physiological quality its value and true significance, we must always refer it to the whole and draw final conclusions only in relation to its effects on the whole. U The existence of unicellular organisms is the flagella, for example. in response to changes in epitome of life in its simplest form. Even th lly conflicting demands in order to survive. multicellular organisms, the transition from r Unicellular organism must, on the one hand, specialized cell groups to organs, the emer- c isolate itself from the seeming disorder of its gence of the two sexes, the coexistence of in- inanimate surroundings, yet, as an"open sy dividuals in social groups, and the transition m"(p.40), it is dependent on its environ- from water to land have tremendously 日 hent for the exchange of heat, oxygen, creased the efficiency, survival, radius of nutrients. waste materials and informatic tion, and independence of living organisms. Isolation"is mainly ensured by the cell This process required the simultaneous devel- frastructure within the which prevent the potentially fatal mixing of m. Nonetheless, the individual cells of watery solutions the body still need a milieu like that of the side and outside the cell protein molecules ea for life and survival. Today, the rithin the cell membrane ensure the xtracellular fluid is responsible for providing bility of the membrane barrier. They may constant environmental conditions (B), bu complex transport proteins known as carriers fact, it is even smaller than the intracellular (p. 26 ff. ) Both types are selective for cer- volume(p. 168). Because of their metabolic n substances, and their activity is usually activity, the cells would quickly deplete the regulated. The cell membrane is relatively well oxygen and nutrient stores within the fluid meable to hydrophobic molecules such as and flood their surroundings with waste prod es. This is useful for the exchange of O, and ucts if organs capable of maintaining a stable CO2 and for the uptake of lipophilic signal sub- internal environment had not developed. This ances, yet exposes the cell to poisonous gases is achieved through homeostasis, a process which physiologic self-regulatory mecha- oxae such as organic solvents. The cell m nisms(se maintain steady states in brane also contains other proteins-namely, the body through coordinated physiologic tivity. Specialized organs ensure the con- nals from the external environment and con- tinuous absorption of nutrients, electrolyte (signal transduction), and enzymes enable the via the urine and feces. The circulating blood cell to metabolize extracellular substrates. connects the organs to every inch of the body Let us imagine the primordial sea as the ex and the exchange of materials between th ternal environment of the unicellular or- blood and the intercellular spaces(interstices nism(A). This milieu remains more or less creates a stable environment for the cells. Or utrients from it and excretes waste into it. In sorb nutrients and make them available by te of its simple structure, the unicellular or- processing, metabolizing and distributing nism is capable of eliciting motor responses them throughout the body. The lung is re o signals from the environment. This is sponsible for the exchange of gases(O2 intake, hieved by moving its pseudopodia or CO2 elimination), the liver and kidney for the p
2 1 Fundamentals and Cell Physiology “. . . If we break up a living organism by isolating its different parts, it is only for the sake of ease in analysis and by no means in order to conceive them separately. Indeed, when we wish to ascribe to a physiological quality its value and true significance, we must always refer it to the whole and draw our final conclusions only in relation to its effects on the whole.” Claude Bernard (1865) The existence of unicellular organisms is the epitome of life in its simplest form. Even simple protists must meet two basic but essentially conflicting demands in order to survive. A unicellular organism must, on the one hand, isolate itself from the seeming disorder of its inanimate surroundings, yet, as an “open system” ( p. 40), it is dependent on its environment for the exchange of heat, oxygen, nutrients, waste materials, and information. “Isolation” is mainly ensured by the cell membrane, the hydrophobic properties of which prevent the potentially fatal mixing of hydrophilic components in watery solutions inside and outside the cell. Protein molecules within the cell membrane ensure the permeability of the membrane barrier. They may exist in the form of pores (channels) or as more complex transport proteins known as carriers ( p. 26 ff.). Both types are selective for certain substances, and their activity is usually regulated. The cell membrane is relatively well permeable to hydrophobic molecules such as gases. This is useful for the exchange of O2 and CO2 and for the uptake of lipophilic signal substances, yet exposes the cell to poisonous gases such as carbon monoxide (CO) and lipophilic noxae such as organic solvents. The cell membrane also contains other proteins—namely, receptors and enzymes. Receptors receive signals from the external environment and convey the information to the interior of the cell (signal transduction), and enzymes enable the cell to metabolize extracellular substrates. Let us imagine the primordial sea as the external environment of the unicellular organism ( A). This milieu remains more or less constant, although the organism absorbs nutrients from it and excretes waste into it. In spite of its simple structure, the unicellular organism is capable of eliciting motor responses to signals from the environment. This is achieved by moving its pseudopodia or flagella, for example, in response to changes in the food concentration. The evolution from unicellular organisms to multicellular organisms, the transition from specialized cell groups to organs, the emergence of the two sexes, the coexistence of individuals in social groups, and the transition from water to land have tremendously increased the efficiency, survival, radius of action, and independence of living organisms. This process required the simultaneous development of a complex infrastructure within the organism. Nonetheless, the individual cells of the body still need a milieu like that of the primordial sea for life and survival. Today, the extracellular fluid is responsible for providing constant environmental conditions ( B), but the volume of the fluid is no longer infinite. In fact, it is even smaller than the intracellular volume ( p. 168). Because of their metabolic activity, the cells would quickly deplete the oxygen and nutrient stores within the fluids and flood their surroundings with waste products if organs capable of maintaining a stable internal environment had not developed. This is achieved through homeostasis, a process by which physiologic self-regulatory mechanisms (see below) maintain steady states in the body through coordinated physiological activity. Specialized organs ensure the continuous absorption of nutrients, electrolytes and water and the excretion of waste products via the urine and feces. The circulating blood connects the organs to every inch of the body, and the exchange of materials between the blood and the intercellular spaces (interstices) creates a stable environment for the cells. Organs such as the digestive tract and liver absorb nutrients and make them available by processing, metabolizing and distributing them throughout the body. The lung is responsible for the exchange of gases (O2 intake, CO2 elimination), the liver and kidney for the The Body: an Open System with an Internal Environment 1 Fundamentals and Cell Physiology Cardiovascular, renal, and respiratory failure
Plate 1.1 Internal and External Environment A. Unicellular organism in the constant external environment of the primordial sea Primordial Signal Substance absorption Heat Water 3号225 Motility Excretion B. Maintenance of a stable internal environment in humans Integration through External signal and hormone Emission off Exchang of gase: (water, salt) Behavior cellular Intersticespace nutrients Distribution
31 Fundamentals and Cell Physiology Plate 1.1 Internal and External Environment ! " # # # ! !