Transcript ANIMAL FORM & FUNCTION

ANIMAL FORM
& FUNCTION
 Campbell, 6th ed., Chapter 40
Nancy G. Morris
Volunteer State Community College
Unifying themes from A & P:
 Correlation between form & function
 Functions are properties that emerge
from the specific shape & order of body
parts
 Living things have the capacity to
respond & adjust to environmental
changes
 1) over the long term by adaptation & natural
selection
 2) over the short term by physiological changes
Levels of Structural Organization
 There is a structure hierarchy of life:
atoms -> molecules -> supramolecules -> cell
 The cell is the smallest unit of life.
 The hierarchy of multicellular organisms is:
cells -> tissues -> organs -> organ systems
Function Correlates with Structure
in the Tissues of Animals
 Tissues are groups of cells with a common
structure and function.
 Cells may be held together by a sticky
coating or woven together in a fabric of
extracellular fibers.
 There are five major groups of tissues:
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Epithelial
Connective
Nervous
Muscle
Blood
Epithelial Tissues
 Simple – one layer of cells
 Stratified or striated – multiple tiers of cells
 Pseudostratified – one layer of cells that appears
to be multiple because cells vary in length.
 Cell shapes are cubodial (like dice), columnar
(bricks on end), squamous (like flat floor tiles).
 Some are specialized for absorption or secretion.
 Some are ciliated.
 The structure fits function: simple squamous
epithelium is leaky & is specialized for exchange
of materials by diffusion. Found lining the blood
vessels and air sacs of the lungs.
Connective Tissues
 Characterized by a sparse cell population
scattered through an extensive extracellular
matrix.
 Functions to bind & support.
 Matrix is web of fibers embedded in a
homologous substance.
 Collagenous fibers – 3 collagen molecules
 Elastic fibers – long threads of elastin; quick
resilience.
 Reticular fibers – branched w/ tightly woven
 Fabric joining connective & adjacent tissues
 Figure 40.3
Nervous Tissues
 Nervous tissue senses stimuli &
transmits signals from one part
of the animals to another.
Muscle Tissue
 Muscle is the most abundant of
vertebrate tissues.
 Consists of long, excitable cells
capable of contraction.
Organ systems are interdependent.
 Tissues are organized into organs in all but
the simplest animals.
 In some organs, the tissues maybe layered
(Figure 40.6).
 Organs are suspended by sheets of mesenteries.
 Heart & lungs are suspended in the thoracic
cavity.
 The thoracic cavity is separated from the
abdominal cavity by the diaphragm.
Organ systems are interdependent.
 Several organs with separate functions
that act in a coordinated way make up an
organ system.
 Systems are interdependent: an
organism is a living whole greater than
the sum of its parts.
Bioenergetics
 Animals are heterotrophs that harvest
chemical energy from the food that they
eat.
 Animals exchange energy with the
environment.
 As heterotrophs, animals require energy
from organic molecules synthesized by
other organisms, (Figure 40.7)
Energy input
(ingestion of food)
Digestion
•(emzymatic hydrolysis of food)
Absorption
•(absorption of small energy-containing
molecules by body cells)
Catabolism
•(cellular respiration & fermentation harvest chemical
energy from food molecules)
Some energy stored
ATP
Some energy lost as
as heat to surroundings
Metabolic rate provides clues
•Bioenergetics: the study of the
balance between energy intake and
energy loss within an organism.
•provides clues as to how an animal
adapts to its environment.
Metabolic Rate
 Total amount of energy an animal uses per
unit time
 Usually measured in calories or kilocalories
 Rate based on:
– Amount of oxygen used for an animal’s
cellular respiration
– Amount of an animal’s heat loss per unit
of time
Metabolic Rate
 Every animal has a range of metabolic
rates:
– Minimal rates support basic life
functions, such as breathing,
– Maximal rates occurs during peak
activities, such as all-out running.
Endo or Ecto?
 Endotherms – animals which generate
their own body heat metabolically
– birds & mammals
 Ectotherms – animals that acquire most
of their body heat form the
environment
– fish, amphibians, reptiles, &
invertebrates
Metabolic Rate vs. Body Size
 There is an inverse relationship between
metabolic rate and size!
 Smaller animals consume more calories per
gram than larger ones.
 Correlated with a higher metabolic rate &
need for faster rate of O2 delivery to the
tissues.
 Smaller animals also have higher breathing
rates, blood volumes, heart rates.
Body Plans & External Environment
 Physical support on land depends on
adaptation of body proportions & posture.
– Greater demand for support comes with
increased body weight.
– Bioenergetics play a big role in loadbearing, since crouched posture is partly
a function of muscle contraction,
powered by chemical energy.
Body size and shape affect interactions
with the environment…
 Animal cells must have enough surface area
in contact with an aqueous medium to allow
adequate environmental exchange of
dissolved oxygen, nutrients, & wastes.
 Cell size is limited by surface area to
volume ratio.
 As cell size increases, volume increases
proportionately more than surface area.
SO…..
Body size and shape affect interactions
with the environment
 Some animals have a body plan that places
all cells in direct contact with their aqueous
environments;
1) two layered sac – both layers of the
body are bathed in water (Hydra).
– 2) Flat-shaped body with maximum
surface area exposed to the aqueous
environment. (tapeworms)
Body size and shape affect interactions
with the environment
 Complex animals have a smaller surface
area to volume ratio & thus lack adequate
exchange area on the outer surface.
 1) They have highly folded, moist, internal
surfaces for exchange (lungs, gills).
 2) Circulatory system that shuttles materials
between specialized exchange surfaces.
Figure 40.10
Mechanisms of Homeostasis
 Interstitial fluid
– Fills spaces between cells
– Exchanges nutrients, wastes, gases
with blood carried in capillaries
 Homeostasis depends on feedback
– 1) receptor – detects internal change
– 2) control center – processes the info
form receptor & informs effector
– 3) effector – provides the response
Mechanisms of Homeostasis
 As a control system operates: the
effector’s response feeds back and
influences the magnitude of the stimulus
by depressing it = negative feedback
(Fig 40.12) OR
 the effector’ response feeds back
and influences the magnitude of
the stimulus by enhancing it =
positive feedback.(blood clotting)