Download Animal Form and Function are Correlated at all levels of organization

Animal Form and Function are Correlated at all
levels of organization
-Tissue are groups of cells that have a common
structure and function
-Tissues are further organized into functional
units called organs
-Groups of organs that work together make up
organ systems
Ex.: The digestive, circulatory, and excretory
-For animal survival, tissues, organs, and organ
systems must act in a coordinated manner
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 supportive surface called th
basement membrane
-The outside surface is facing either air or fluid
environment
Connective Tissue
-Mainly supports and binds other tissues
-It consists of scattered cells within an
extracellular matrix
-Some connective tissues are cartilage, tendons,
ligaments, bone, and blood
Muscle Tissue
-Is responsible for nearly all types of body
movement
-Muscle filaments are made of the proteins actin
and myosin
-Muscle fibers contract when they are stimulated
by a nerve impulse
-Muscle tissue is the most abundant tissue in
most animals
-There are three types of muscle:
Skeletal, cardiac, and smooth
Nerve Tissue
-The functional unit of nervous tissue is the
nerve cell or neuron
-This tissue senses stimuli and transmits signals
from one part of the body to another part of the
body, including to other neurons, glands,
muscles, and the brain
Two major systems specialize in control and
coordination: Endocrine system and Nervous
system
-In the endocrine system, chemical signals called
hormones are released into the blood stream
and are broadcast throughout the body
-Different hormones cause specific effects, but
only in cells with specific receptors for the
release hormone
-In the nervous system, neurons transmit
information between specific locations
-Only three types of cells receive nerve impulses:
neurons, muscle cells, or endocrine cells
Feedback Control Loops maintain the Internal
Environment in many Animals
-In homeostasis animals maintain a relatively
constant internal environment, even when the
external environment changes significantly
-Homeostatic control systems function by having
a set point (like a body temperature to
maintain), sensors to detect any stimulus above
or below the set point and a physiological
response that helps return the body to its set
point
Negative feedback
-The animal responds to the stimulus in a way
that reduces the stimulus
Ex.: Temperature
Positive Feedback
-A change in some variable triggers mechanisms
that amplify rather than reverse the change
Homeostasis Gone Wrong
-If regulatory feedback mechanisms are altered
or breakdown, homeostasis cannot be achieved
and this malfunction can cause serious disease in
an organism
Ex.: Diabetes Mellitus as a result of the nonregulation of insulin in the bloodstream
-Homeostatic processes for thermoregulation
reflect common ancestry but also show
divergence due to adaptation to different
environments
Thermoregulation
-Refers to how animals maintain their internal
temperature within a tolerable range
-Although all animals use negative feedback
mechanisms to regulate thermoregulation
(which shows common ancestry) they use a
variety of methods to do so based on how they
have adapted to their environment (which shows
divergence)
Endotherms
-Animals and birds
-Are warmed mostly by heat generated by
metabolism
Ectotherms
-Most invertebrates, fishes, amphibians, and
reptiles
-Generate relatively little metabolic heat, gaining
most of their heat from external sources
Concurrent Exchange
-In many birds and mammals, reduction of heat
loss relies on concurrent exchange
-Heat transfer involves ant-parallel arrangement
of blood vessels such as warm blood from the
core of the animal, and route to the extremities
-Heat that would have been lost to the
environment is conserved in the blood returning
to the core of the animal