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)