Transcript Unit III Organs and Organ Systems

Unit V
Anatomy and Physiology of
Plants and Animals
Learning Goal 2
Explain the function of structures
involved in protection, support, and
movement of plants, animals and
humans.
Plants
• Protection
Dermal tissue in plants is the
outermost protective layer.
It consists of epidermal cells
that are generally
unspecialized except for those
that form guard cells
surrounding the stoma, and
trichomes.
Trichomes are tiny outgrowths
of epidermal cells that may
give leaves a hairy
appearance. They may exude
sugars, toxins. Trichomes from
root epidermal cells are known
as root hairs, and help plants
absorb water.
• Support
Ground Tissue – Makes
up most of the plant body
and functions in
metabolism, storage and
support.
There are 3 types:
Parenchyma – makes up
the bulk of soft tissues in
plants. Surrounded by air
spaces especially in
leaves to facilitate
movement of gases.
• Collenchyma
This tissue provides
flexible support to
help strengthen plant
parts that are still
growing.
Cells are typically
elongated and
collenchyma tissue
appears “stringy”.
• Sclerenchyma
This tissue provides rigid
support and protection to
plants.
Cells have thick
secondary walls
containing lignin and
perforations through
which water can pass.
Mature cells die as they
are encased in lignin, but
continue to provide
support for the plant.
• Movement
Plants don’t move
independently from place to
place but can bend in
response to environmental
stimuli such as light
(phototropism) or touch
(thigmotropism)
This occurs due to the
presence of hormones called
auxins which stimulate cell
elongation on the shaded side
of the stem.
Animals
• Protection
Epithelial tissues cover
body surfaces and the
surfaces of internal
organs, as well as line
cavities and ducts within
the animal body.
They provide protection
from invasion by bacteria
and viruses and secrete
and absorb substances.
• Classifications of
Epithelial Tissue:
Simple or stratified,
meaning single or multilayered.
Squamous – flattened
cells
Cuboidal – roughly
shaped like cubes
Columnar - elongated
• Support
Skeletal Systems:
Hydrostatic Skeletonsconsist of muscles and
fluid that provide support
for the animal with no
rigid support from tissue
like bone.
Found in many
invertebrates like worms,
and cnidarians.
• Exoskeletons
A rigid external body
covering that provides
support and
protection.
May be made of hard
calcium carbonate
such as in mollusks or
chitin as in
arthropods.
• Endoskeletons
Consist of internal
body structures made
of bone or cartilage
and protection in
some invertebrates
and all vertebrates.
Movement
• Muscle tissue provides
all animals with the ability
to move around
independently.
• Muscle cells can
contract or shorten due to
the interaction of two
proteins, actin and
myosin.
• There are three types of
muscle tissue, skeletal,
cardiac, and smooth
which produce movement
in vertebrates.
• Skeletal Muscle
Also called muscle
fibers, are attached
by tendons to the
skeleton.
They contain many
nuclei and are packed
with actin and
myosin molecules.
• Cardiac Muscle
This is the contractile tissue of
the heart.
It has a striated appearance
because it contains actin and
myosin molecules arranged in
a similar manner to skeletal
muscle.
They form an interlinked
network that makes heart
muscle contract in all
directions, producing a
squeezing or pumping action.
• Smooth Muscle
Found in the walls and
tubes of cavities in the
body.
Contractions of smooth
muscle move and mix the
stomach and intestinal
contents, constrict blood
vessels, and push the
infant out of the uterus
during childbirth.
Patterns of Movement in
Vertebrates
• Fishes and snakes
have muscle blocks
located on either side
of backbone that give
them a side-to-side
movement for forward
motion.
• Amphibians and
reptiles have limbs
on sides in a “push-up
position” causing
them to walk in a
side-to-side motion.
• Mammals have limbs
straight under them
giving them more of
an up and down
motion when they
walk.