Chapter 32: Homeostasis and Endocrine Signaling

anatomy

study of the biological form of an organism

physiology

study of the biological functions an organism performs

interstitial fluid

immediate environment of most cells; control systems regulate this to allow animals to maintain a stable internal environment

tissues

groups of cells with similar appearance and common function

organs

different types of tissues organized into functional units

organ systems

groups of organs that work together

4 types of animal tissues

epithelial, connective, muscle, nervous

epithelial tissue

coverings/linings

connective tissue

support

muscle tissue

movement

nervous tissues

control

regulating, conforming

animals are faced with changing environments; manage internal environment by ___________ or ______________.

regulator

use internal mechanisms to maintain the internal despite external change

conformer

allows its internal condition to change in accordance with external changes

true

T/F: animals may regulate some internal conditions and not others

homeostasis

maintain a steady internal state despite changing external environment; can be for a range of factors (for humans: body temp, blood pH, glucose concentration)

true

T/F: regulation of room temperature by a thermostat is analogous to homeostasis

set point

achieve homeostasis by maintaining a variable at or near a ____________.

stimulus, sensor, response

Fluctuations above or below the set point serve as a _______; these are detected by a _______ and trigger a _______.

negative feedback

a control mechanism that reduces the stimulus; homeostasis relies largely on this; dampens a stimulus

moderates

homeostasis ___________, but does not eliminate, changes in the internal environment

false

T/F: set points and normal ranges usually change

thermoregulation

how animals maintain an internal temperature within a tolerable range

endothermic

generate heat by metabolism (i.e. birds and mammals); maintain a stable body temp in the face of large fluctuations in environmental temperature

ectothermic

gain heat from external sources (i.e. most invertebrates, fishes, amphibians, and non-avian reptiles); consume less food b/c their heat source is environmental

organisms exchange heat by

radiation, evaporation, convection, conduction

radiation

emission of electromagnetic waves

evaporation

removal of heat from the surface of a liquid that is losing some molecules as gas

convection

transfer of heat by movement of air or liquid past its surface

conduction

direct transfer of heat between molecules of objects

true

T/F: heat is transferred from an object of higher temperature to one of lower temperature

vasodilation

widening of the diameter of blood vessels near the surface = heat loss

vasoconstriction

narrowing of diameter of blood vessels reduces heat loss

countercurrent exchange

transfer of heat or solutes between fluids that are flowing in opposite directions; arteries and veins are adjacent (i.e. birds & mammals)

acclimatization

physiological adjustment to environmental changes

hypothalamus

triggers heat loss or heat generating mechanisms in mammals

endocrine system

signaling molecules (hormones) released into the bloodstream by endocrine cells reach all locations in the body; slow and long lasting; signal is hormones

nervous system

neurons transmit signals along dedicated routes, connecting specific locations in the body; information is conveyed by the pathway taken (i.e. certain receptors are activated); fast and specific

endocrine system and nervous system

two major systems for controlling and coordinating responses to stimuli

feedback loop

links the response back to the original stimulus in an endocrine pathway

positive feedback

reinforces a stimulus to increase the response

hormone cascade

anterior pituitary hormones that target endocrine tissues often form part of a _______________ ____________.