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Why is physiology important?
-important for understanding health and disease of both nonhuman animals and humans
-allows us to understanding the inner workings of animals
Why do modern day animals possess the mechanisms they do?
because of evolution
T/F- Natural Selection is a key process of evolutionary origin
true
T/F- Most cells of an animal are exposed to the external environment
FALSE- most are exposed to the INTERNAL environment
What structural property of an animal persists throughout time?
its organization
T/F- The internal environment alwasy changes when the external environment does
FALSE- It may be permitted to change BUT it may be kept constant
T/F- Body size is one of an animals most important traits
True
How do mammals and birds demands of homeothermy?
by hibernations, torpor, or related processes
What is the ultimte line of defense against overheating?
Active evaporation cooling
T/F- Homeothermy is metabolically inexpensive
FALSE- it is metabolically expensive
What is the primary importance of studying physiology, according to the text?
Understanding the inner workings of animals
Which of the following best describes the two central questions in physiology?
Mechanism and origin
According to the text, what is the study of mechanism in physiology concerned with?
How modern-day animals carry out their functions
What does the study of origin in physiology seek to answer?
Why modern-day animals possess certain mechanisms
True or False: Natural selection is a key process of evolutionary origin.
lection is a key process of evolutionary origin.
Correct Answer: True
Mechanism and adaptive significance always imply each other.
False
What is the primary structural component of cell membranes?
Phospholipids
How do phospholipids in cell membranes behave?
They move freely by diffusion within each membrane leaflet.
Which of the following is NOT a functional category of proteins found in cell and intracellular membranes?
A) Channels B) Enzymes C) Ribosomes D) Receptors
ribosomes
What do tight or septate junctions do in a simple epithelium?
They seal the spaces between adjacent cells.
What type of junction divides the cell membrane into chemically and functionally distinct apical and basolateral regions in an epithelium?
Tight junctions
What is the purpose of a basement membrane in an epithelium?
It provides a permeable boundary between the cells and underlying tissue
How do materials pass through epithelia?
Both through paracellular paths and transcellular paths.
What is the primary role of enzymes in cellular reactions?
They accelerate reactions by lowering activation energy.
How do enzymes bind to their substrates?
Through weak, noncovalent bonds.
What is cooperativity in enzymes, and how is it achieved?
It is the phenomenon where one substrate affects the binding of others. It measures the enzyme–substrate affinity.
How do most hydrophilic extracellular signaling molecules interact with cells?
They bind to cell-membrane receptor proteins.
What is the primary function of ligand-gated channels when activated by their ligands?
They change ion fluxes across cell membranes.
What is the role of second messengers in cell signaling?
They amplify the effects of extracellular signals
What gives rise to the most elementary form of simple solute diffusion?
Concentration gradients
What often influences the diffusion of charged solutes at membranes?
Electrical gradients
How is the diffusion of ions across cell membranes determined?
By simultaneous concentration and electrical effects
What can concentration gradients create that may alter concentration gradients themselves?
Electrical gradients
What is facilitated diffusion?
The movement of solutes through channels or carriers without energy input
What are active transport and facilitated diffusion examples of?
Active-transport mechanisms
What are the basic properties of active-transport mechanisms?
They require energy input to move solutes against their concentration gradient.
What is the primary difference between primary and secondary active transport?
Primary active transport directly uses ATP as an energy source, while secondary active transport uses energy stored in electrochemical gradients.
How do two epithelial ion-pumping mechanisms help freshwater fish maintain their blood composition?
By actively transporting ions against their concentration gradients
Which form of energy is considered totipotent for animals?
Chemical-bond energy
What are the three major functions for which animals use their absorbed chemical energy?
Biosynthesis, maintenance, and generation of external work
What happens to some energy when high-grade energy is transformed into another form within animals?
It is degraded to heat (low-grade energy).
Why is an animal's metabolic rate important?
It provides a measure of the total activity of all its physiological mechanisms.
What is an animal's metabolic rate?
The rate at which it converts chemical energy into heat and external work
Which measure is the most common method of determining an animal's metabolic rate?
Rate of O2 consumption
What does metabolic rate help determine regarding an animal's relationship with its ecosystem?
The amount of food an animal needs and the energy it removes from its ecosystem
What is the typical allometric exponent (b) that relates metabolic rate to body weight within phylogenetically related groups of animals?
0.7
How does the weight-specific BMR of small-bodied species compare to that of large-bodied species within related groups?
It is 20 times higher.
What are some effects of the allometric relation between metabolic rate and body weight on ecosystems?
t influences population biomasses and community organization
What is Rubner's surface "law" based on?
The relationship between heat loss and metabolic rate.
What are the four major sets of reactions involved in aerobic catabolism?
Glycolysis, Krebs cycle, electron transport, oxidative phosphorylation
What is the maximum net yield of ATP molecules per glucose molecule in carbohydrate oxidation?
29 ATP molecules
Which process releases lactic acid as an energy-rich compound?
Anaerobic glycolysis
Which process releases lactic acid as an energy-rich compound?
Submaximal exercise
What metabolic transition occurs at the start of even light submaximal exercise?
Oxygen deficit
Why does the pace of all-out exertion decline as the duration of exercise increases?
Due to a decrease in oxygen availability
What happens to many animals adapted to living without oxygen when deprived of O2?
They enter a state of metabolic depression
What is the key part of the strategy for survival in turtles capable of total-body anoxia?
Metabolic depression of the CNS
Which aquatic animals have the ability to convert lactic acid to ethanol during total-body anoxia?
Fish
Which mechanism allows heat transfer between objects at the speed of light?
hermal radiation
What type of heat transfer occurs due to the flow of a material substance, such as wind?
Convection
Why is evaporation considered a potent mechanism for heat transfer?
It absorbs a great deal of heat per gram of water.
What is the term for animals in which body temperature is determined by equilibration with external thermal conditions?
Poikilotherms
What is the most common response of poikilotherms to cold or low-temperature environments in terms of metabolic rate?
Compensation
How do different species of poikilotherms adapt to different body temperatures over evolutionary timescales?
By synthesizing different molecular forms of protein molecules
Which mechanism is primarily responsible for modulating insulation in mammals and birds to regulate body temperature?
Changes in posture
What is the principal mechanism of increasing heat production in mammals and birds below thermoneutrality?
Nonshivering thermogenesis
What is the primary line of defense against overheating in mammals and birds in hot environments?
Evaporative cooling
What is the primary source of heat for endothermy in tunas, lamnid sharks, and billfish?
Chemical reactions
Which mechanism do many solitary insects use to warm their thorax during flight or activity?
Shivering
How do social bees and wasps in colonies maintain stable hive temperatures?
By group efforts to regulate thoracic insulation
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