Chapter 40: Animal Bodies and Homeostasis
Organization of Animal Bodies
All animal cells share similarities in the ways in which they
o
Exchange materials with their surroundings
o
Obtain energy from organic nutrients
o
Synthesize complex molecules
o
Reproduce themselves
o
Directly respond to signals in their immediate environment
Cells
with similar properties group to form
tissues
Tissues combine together to form
organs
o
Has to have 2 or more types of tissue to be classified an organ
Organs are linked to form
organ systems
Cells
Tissues
Organ
Organ System
A cell will commit to a specific type of function or job –
differentiation
Vertebrate Tissues
4 types of cells that form tissue
o
Muscle Tissue
= most abundant tissue / unique to animals (allows animals to
move)
Skeletal
Muscle
– Attached to bone or exoskeleton, voluntary control,
striated, multinucleated
Striation – molecules in muscle are organized in stripes
Under voluntary control – you decide if you move it or not
Smooth
Muscle –
Surrounds tubes and cavities for propulsion of
contents, involuntary control, not striated
Lines most of your organs
[Just know it exists and is different from skeletal and cardiac]
Cardiac
Muscle –
Only in the heart, involuntary control, striated
One nucleus per cell.
Intercalated disks – have holes in them so that one cell can
communicate to the neighboring cell; communicate with electrical
signal
o
Nervous Tissue
Conduct electrical signals from one part of the animal’s body to another
Allows organisms to interact with their environment – required for
animals to move … cant move without nervous system
Single nerve cell called a
neuron
(functional unit of nervous system)
–
neurons have many different shapes; can be the length of your leg or
giraffes neck [thin but long]
Electrical signals produced in a nerve cell may stimulate or inhibit other
cells to
Initiate new
action potentials
in other neurons
Stimulate muscle
to contract
Stimulate glands
to release chemicals
o
Epithelial Tissue
Will protect surfaces and secrete/make chemicals
Organized by shape or stratification (or layers)
Pseudostratified – false stratification
Sheets of
densely-packed cells
that cover the body or enclose organs &
line the walls of body cavities
All are
asymmetrical
or polarized
Rest on basal lamina or basement membrane
Can function as
selective barriers
Come in 3 forms: squamous (squashed), columnar (column), and cuboidal
forms
o
Connective Tissue = most diverse tissue
Connect, anchor, and support
Includes
blood,
adipose,
bone
,
cartilage,
loose
and
dense
connective tissue (ligaments and tendons)
Forms a lot of
extracellular matrix
around cells to make it connective
tissue
Provides scaffold for attachment
Protects and cushions
Mechanical strength
Transmit information
Like all animal cells, they have a cell membrane, nucleus, mitochondria,
ER, GA, cytoskeleton
But connective tissue cells have lots of extracellular
matrix
