Chapter 41
Physiology, Homeostasis, and Temperature Regulation
1. Define tissue and explain where it falls in the
hierarchy of structural organization.
---groups of cells with common structure and function
---celltissuesorgansorgan systemsorganism
2. From micrographs or diagrams, correctly identify the
following animal tissues, explain how their structure
relates to function, and give examples of each:
Epithelial tissue: cuboidal, columnar, squamous
Connective tissue: adipose, cartilage, bone
Muscle tissue: skeletal (striated), cardiac, smooth,
nervous
---Epithelial tissue formed from sheets of tightly packed
cells, covers outside of body/lines organs and body
systems
--cells closely joined & riveted by tight junctions
--functions as barrier against mechanical injury,
invading organisms, and fluid loss
--free surface exposed to air or fluid
--cells at base attached to basement membrane (dense
layer of extracellular material)
--characterized by number of layers and shape of free
surface cells
-simple epithelium = one layer of cells
-stratified = multiple tiers (layers) of cells
-pseudostratified = one layer that appears to be
multiple because they vary in length
-cell shapes are cuboidal (like dice), columnar
(bricks on end), or squamous (like flat floor
tiles)
-cuboidal epithelium = epithelia of kidney tubules
-columnar epithelium = lining of intestines
-squamous = line air sacs of lungs
---Connective tissue characterized by sparse cell
population through an extensive extracellular matrix
--functions to bind and support other tissues
--matrix is web of fibers embedded in homogenous
ground substance
--consists of loose weave of 3 types proteinaceous
fibers: collagenous, elastic, & reticular
--collagenous fibers are bundles of fibers containing
3 collagen molecules each; have great tensile strength
and resist stretching
--elastic fibers are long threads of protein (elastin),
lend tissue the resilence to quickly return to
original shape
--reticular fibers are branched, form tightly woven
fabric joining connective tissue to adjacent tissues
--major types: loose connective, adipose, fibrous
connective, cartilage, bone, & blood
--Adipose tissue is loose connective tissue specialized
to store fat in adipose cells distributed throughout
its matrix
-insulates body and stores fuel molecules
-each adipose cell has one large fat droplet
-adipose tissue covers some internal organs
--Cartilage is composed of collagenous fibers embedded
in chondroitin sulfate (protein-carbohydrate ground
substance)
-chondrocytes secrete both collagen & chondroitin
sulfate
-makes cartilage both strong and flexible
-chondrocytes confined to lucunae (scattered spaces
within ground substance
-comprises skeleton of all vertebrate embryos
-retained in some areas: nose, ears, trachea,
intervertebral discs, & ends of some bones
--Bone is mineralized connective tissue
-osteoblasts are bone forming cells-deposit matrix of
coì¥Á M
ð ¿
£!
bjbjâ=â=
ÿÿ
ÿÿ
l
¨
¨
¨
¨
¨
¨
¨
$
2
2
2
2
F
<
$
2
Ž
Ž
Ž
Ž
Ž
Ž
Ž
Ž
$
É
é
p
<
¨
Ž
Ž
Ž
Ž
Ž
¨
<
¢
Ž
¢
Ž
¨
Q
¢
Ž
¨
Ž
¨
Ž
¢
Ž
¢
¢
t
¢
¨
Ž
2
‚
¨
@m²3˜Â$
˜
g
0
Y
¢
Y
¢
<
ø
,
¨
¨
¨
¨
Ù
Chapter 40 An Introduction
to Animal Structure and Function
1. Define tissue an
explain where it falls in t
e hierarchy of
structural organi
ation.---groups of cells with common structure and
unction---cell(tissues
organs(organ systems(organism2. From micrographs
r diagrams, correctly identify the following anima
tissues, explain how their structure relates to fun
tion, and
ive examples of each:Epithelial tissue: cuboidal, column
r, squamousConnective tissue: a
ipose, cartilage, boneMuscle tissue: skeletal (striated),
ardiac, smooth,
nervo
s---Epithelial tissue formed from sheets of tightly
acked
cells, covers outside of body/lines organs and bod
¼
systems
--cells closely joined & rive
ed by tight junctions
--functions as barrier against mechanical injury,
invading organisms, and fluid loss
--free surface exposed to air or fluid
--cells at base attached to
basement membrane (dense
layer of extracellular material
--characterized by number of layers and shapeange of
of dissolved oxygen, nutrients, & wastes
--this imposes constraints to animal size and shape
---most complex animals have a smaller surface area to
volume ratio and thus lack adequate exchange area on
the outer surface
---instead, highly folded, moist, internal surfaces
exchange materials with environment
---circulatory system shuttles materials between these
specialized exchange surfaces
---environmental exchange surfaces are internal & protected
from desiccation, so animal can live on land
---cells are bathed with internal body fluid, so the animal
can control the quality of the cells’ immediate environment
4. Describe several body shapes that maximize external
surface area in contact with the environment.
---single-celled organisms have entire surface area
in contact with environment
---two-layered sac, utilized by some multicellular animals,
has body wall only 2 cell layers thick (body cavity of
Hydra)
---flat-shaped body with maximum surface area exposed to
aqueous environment (tapeworm thin and flat so most
cells bathed in intestinal fluid of the worm’s
vertebrate host
---highly folded, moist, internal surfaces (most complex
animals)
5. Repeat of question 3.
6. Describe the location and function of interstitial
fluid.
---interstitial fluid is the fluid between the cells
that comprise the internal environment of vertebrates
--fills spaces between the cells
--exchanges nutrients and wastes with blood carried
in capillaries
7. Define homeostasis.
---homeostasis is dynamic state of equilibrium in which
internal conditions remain relatively stable, “steady
state”
--allows organism to maintain (fairly) constant
conditions in internal environment even when external
environment changes
8. Distinguish between negative and positive feedback.
---negative feedback is homeostatic mechanism that stops
or reduces the intensity of the original stimulus and
consequently causes a change in the variable that is
opposite in direction to the initial change
--most common homeostatic mechanism in animals
--lag time between sensation and response so variable
drifts slightly above and below set point
thermostatic control of room temperature
---positive feedback is homeostatic mechanism that
enhances the initial change in a variable
--rarer than negative feedback/controls episodic events
--examples are blood clotting and childbirth