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Lecture 1

BIOLOGY 225 Lecture Notes - Lecture 1: Comparative Physiology, Homeostasis, Peripheral Nervous System

Course Code
Xu Haoxing

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Wednesday, September 7, 2016
Biology 225!
Introduction to Animal Physiology and Physiological Regulation
-Animal Physiology: the study of how animals work!
What is an animal?!
-multicellular eukaryotes!
-capable of locomotion (moving from one place to another)!
-Physiological sub disciplines: biological level of organization !
Cell and molecular physiology—genetics, metabolism, organelles!
Systems physiology—functions of organs!
Organismal physiology—whole animal!
Ecological physiological—animal and its environment!
Integrative physiology—multiple levels of organization!
-The most basic unit of physiology is the atom—> atoms make molecules—>
molecules make cells—>cells make tissues—> tissues make organs—> organs
together make organ systems !
-Four major cell types !
Neurons—correspond with nerve tissues!
Muscle cells—three types: skeletal, smooth and cardiac muscle cells!
Epithelial cells—correspond with epithelial tissue!
connective tissue cells—blood cells, bone cells and fibroblasts (in skin and other
-Organ systems!
the nervous system—consists of the brain and spinal cord (central nervous system)
and peripheral nerves (peripheral nervous system)!
-provide communication between cells of the body through electrical signals and
the release of neurotransmitters into small gaps between certain cells!
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Wednesday, September 7, 2016
the cardiovascular system—consists of the heart, blood vessels, and blood!
-transports molecules throughout body in bloodstream!
-Sense of “size”!
atoms are roughly 0.1 nanometer!
nanometer—>micrometer—>millimeter—>centimeter !
-Biological level of organization!
reductionism—understand a system by studying the function of its parts!
emergence—the whole is more than the sum of its parts!
-Processes that cause physiological variation!
developmental physiology—change as animal grows!
environment physiology—change in response to environment!
evolutionary physiology—change due to natural selection!
-Ultimate goals of research!
pure physiology—no specific goal other than knowledge!
applied physiology—medical physiology, comparative physiology!
-Unifying themes in physiology!
physiological process obey physical and chemical laws!
physiological process are usually regulated!
-Homeostasis—maintenance of internal constancy (body temp, blood pressure,
physiological phenotype is a product of genotype and environment!
-genotype—genetic makeup!
-phenotype—morphology, physiology, and behavior!
-Physiological regulation (homeostasis)!
conformers—allow internal conditions to change with external regulations!
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regulators—(i.e. humans) maintain relatively constant internal conditions regardless
of external conditions!
-controlled by feedback loops or reflex control pathways: negative feedback loops
(essential for humans), positive feedback loops, and negative + positive !
-negative feedback in the control of body temperature, if the temperature is too
high then the body brings the internal temperature down
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