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CHAPTER 40BASIC PRINCIPLES OF
ANIMAL FORM AND FUNCTION
By Charith Samarasena
Vocabulary
Acclimatization: physiological adjustment to a change in an environmental factor
Stressed-induced proteins: proteins that are activated by the factors of stress
Heat shock proteins: proteins that help protect other proteins under heat stress
Torpor: a physiological state in which activity is low and metabolism decreases
Hibernation: a physiological state in which metabolism decreases, the heart and respiratory system slow down, and body temperature is maintained at a lower level than normal
Estivation: a physiological state that allows animals to survive in warmer temperatures and very low water supply
Hierarchical Organization of Body Plans (Ascending) Tissues: groups of cells of similar
appearance and common function Organs: functional units of tissue Organ System: groups of organs that
work together providing an additional level of organization and coordination
Tissue
There are 4 types of tissues:-Epithelial-Connective-Muscle-Nervous
Epithelial Tissue
Covers outside of the body and lines the organs and cavities within body
Epithelium have four shapes:-cuboidal (like dice)-columnar (bricks standing on end)-squamous (like floor tiles)
Epithelial Tissue cont’d
Epithelium cells can be arranged as:-simple epithelium (single cell layer)-stratified epithelium (multiple tiers of
cells)-pseudostratified epithelium (single
cell layer varying in height)
Connective Tissue
Bind and support other tissues in the body
Connective tissue cells are scattered throughout extracellular matrix
Types of connective tissue:-cartilage-adipose tissue-fibrous connective tissue (tendons and
ligaments)-loose connective tissue
Muscle Tissue
Responsible for nearly all types of body movement
Consist of filaments containing actin & myosin
Types of muscle tissue:-skeletal muscle-cardiac muscle-smooth muscle
Nervous Tissue
Sense stimuli and transmit signals in the form of nerve impulses from one part of the body to another
Contains neurons and glial cells
Cell Signaling
Can be done via the nervous system Can also be done via the endocrine
system in the form of hormones
4 Ways To Gain, or Lose, Heat From or To Environment Radiation
Evaporation Convection Conduction
Radiation
The emission of electromagnetic waves by all objects warmer than absolute zero
Transfers heat between objects indirectly
Evaporation
Removal of heat from the surface of a liquid that is losing some of its molecules as gas
Convection
Transfer of heat by movement of air or liquid past a surface
Conduction
The direct transfer of heat between molecules of objects by direct contact
Endotherm
Aka regulator; maintains a separate body temperature from that of external environment; uses principle of homeostasis
Homeostasis is not maintained the animal dies
Ectotherm
Aka conformers; change body temperature to match external environment
Heat is gained from external sources If there is not enough heat for the
animal to absorb it dies
5 Methods of Thermoregulation
Insulation Circulatory Adaptations Cooling by Evaporative Heat Loss Behavioral Responses Adjusting Metabolic Heat Production
Insulation
Reduces heat flow between animal and its environment
Sources of insulation include hair, feathers, and layers of fat formed by adipose tissue (all are important for mammals and birds)
Circulatory Adaptations
Vasodilation: relaxing of muscles of vessel walls to increase blood flow; increases body temperature
Vasoconstriction: contraction of muscles of vessel walls to decrease blood flow; decreases body temperature
Circulatory Adaptations cont’d
Countercurrent exchange: the flow of adjacent fluids in opposing directions that maximizes transfer of rates of heat or solutes (especially important in birds and mammals)
Heat transfer involves antiparallel arrangement of blood vessels
Cooling by Evaporative Heat Loss
When body begins to overheat, animals begin to lose water which absorbs a lot of heat
Then, the water evaporates across the skin and into the atmosphere releasing heat (ex. sweating)
Behavioral Responses
Some animals, such as amphibians and reptiles, will simply move to different locations when they feel to hot or cold
Other animals, like invertebrates, move bodies to control heat gain
Some animals may huddle to conserve heat
Adjusting Metabolic Heat Production
Shivering and nonshivering thermogenesis (in cold weather) can increase metabolic heat production
Switching types of thermoregulation can help in heat gain, like switching from ectothermy to endothermy (large reptiles like snakes may do this to keep eggs warm)
Hypothalamus
A component of the brain that contains nerve cells that detect change in temperature throughout body
Crucial to homeostasis because hypothalamus tells blood vessels to constrict or dilate to increase or decrease body temperature
Thermoregulation by Hypothalamus (“-”
feedback)