Download chapter 40 basic principles of animal form and function

CHAPTER 40
BASIC PRINCIPLES OF
ANIMAL FORM AND
FUNCTION
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REVIEW:
1. anatomy—study of an organism’s structure
2. physiology—study of biological function
You Must Know:
1. Four types of tissues and their general functions
2. The importance of homeostasis and examples
3. How feedback systems control homeostasis, and
one example of positive feedback and one
example of negative feedback
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I. Concept 40.1
A. Tissues
1. Are defined as groups of cell that have a common structure
and function
2. Can be organized into functional units called organs
3. Groups of organs that work together make up organ systems
(Ex: digestive, circulatory, and excretory systems)
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B. Four types of tissue:
1. Epithelial Tissue
•Occurs in sheets of tightly packed cells
•Covers the body, lines the organs and acts as a
protective barrier
•One side of the epithelium is always bound to an
underlying surface called the basement membrane (basal
surface)
•Always has one free surface facing either air or a fluid
environment
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2. Connective Tissue
• Mainly supports and binds other tissues
• Consists of scattered cells within an extracellular matrix
• Ex: cartilage, tendons, ligaments, bone, adipose tissue,
and blood
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3. Muscle Tissue
•Responsible for nearly all types of body movement
•Muscle filaments are made of the proteins actin (thin) and
myosin (thick)
•Muscle fibers contract when stimulated by a nerve impulse
•Most abundant tissue in most animals
•Three types of muscle: skeletal (voluntary), cardiac
(involuntary—makes up heart), smooth (involuntary)
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4. Nervous Tissue
•Functional unit is the neuron (nerve cell)
•Senses stimuli and transmits signals from one part of the
body to another part
•Includes other neurons, glands, muscles and the brain
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C. For animal survival tissue, organs, and organ systems
must act in a coordinated manner
1. The Endocrine System
•Involves glands that produce chemicals called hormones that
are released into the bloodstream and carried to specific
glands
2. The Nervous System
•Neurons transmit information between specific locations
•Only three type of cells receive nerve impulses: neuron,
muscle cells, and endocrine cells
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II. Concept 40.2
A. Homeostasis
• Process by which animals maintain a relatively constant
internal environment, even when the external environment
changes significantly
• “steady state”
B. Homeostatic control systems function by having a set point
(body temperature), sensors to detect any stimulus above
or below the set point, and a physiological response that
helps return the body to its set point
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C. Negative Feedback
•Animal response to the stimulus in a way that reduces the
stimulus
•Ex: in response to exercise, the body temperature rises,
which initiates sweating to cool the body
D. Positive Feedback
•Involves a change in some variable that triggers
mechanisms that amplify rather than reverse the change
•Very unstable
•Ex: uterine contractions
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III. Concept 40.3
A. Thermoregulation—refers to how animals maintain their
internal temperature within a tolerable range
B. Endotherms (warm blooded)
• Ex: mammals and birds
• Are warmed mostly by heat generated by metabolism
C. Ectotherms (cold blooded)
• Ex: most invertebrates, fishes, amphibians, reptiles
• Generate relatively little metabolic heat, gaining most of
their heat from external sources
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D. Countercurrent Exchange
•This is the method by which many birds and mammals
reduce heat loss
•Heat transfer involves antiparallel arrangement of blood
vessels such that warm blood from the core of the animal,
en route to the extremities, transfers heart to colder blood
returning form the extremities.
•Heat that would have been lost to the environment is
conserved in the blood returning to the core of the
animals
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Countercurrent Exchange
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