Transcript 20. Unifying Concepts of Animal Structure and Function

Chapter 20
Unifying Concepts of Animal
Structure and Function
PowerPoint Lectures for
Biology: Concepts and Connections, Fifth Edition
– Campbell, Reece, Taylor, and Simon
Lectures by Chris Romero
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Climbing the Walls
• Like Spiderman, geckos can walk up a wall
and across ceilings
• The gecko's ability to "stick" to surfaces results
from special structural adaptations of its body
– Setae, hairs made of protein on the gecko's
toes, contain many spatulae
– Molecules on the spatulae are attracted to
molecules on the walking surface
• The correlation between structure and function
is an overarching concept of biology
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
THE HIERARCHY OF STRUCTURAL
ORGANIZATION IN AN ANIMAL
20.1 Structure fits function in the animal body
• Anatomy is the study of structure
• Physiology studies how structures function
• The functions of the various parts of the body
result from their specific structures
– Example: Flight apparatus of birds provides
strength, support, insulation, stability,
minimal weight
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 20-01
Forearm
Wrist
Finger 1
Internal bone structure
Palm
Shaft
Finger 2
Finger 3
Shaft
Feather
structure
Barb
Barbule
Hook
20.2 Animal structure has a hierarchy
•
Structure in the living world is organized in a series of
hierarchical levels
– Cell: smallest independent unit of life
– Tissue: integrated group of cells that perform a
specific function
– Organ: two or more types of tissues that together
perform a specific task
– Organ system: multiple organs that together
perform a vital body function
– Organism: integrated unit made up of a number of
organ systems functioning together
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 20-02
Cellular level
Muscle cell
Tissue level
Muscle tissue
Organ level
Heart
Organ system level
Circulatory system
Organism level
Many organ systems
functioning together
20.3 Tissues are groups of cells with a common
structure and function
• The cells composing a tissue are specialized
to perform a specific function
• In almost all animals, most body cells are
organized into four main categories of tissues
– Epithelial
– Connective
– Muscle
– Nervous
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20.4 Epithelial tissue covers the body and lines
its organs and cavities
• Epithelial tissue occurs as sheets of closely
packed cells anchored to underlying tissues by
a basement membrane
• Categories of epithelial tissues
– Simple: single layer of cells
– Stratified: multiple layers of cells
– Shapes: squamous, cuboidal, or columnar
• Epithelial tissue functions in protection,
secretion, and exchange
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 20-04
Free surface of
epithelium
Basement
membrane
Cell
Underlying
nuclei
tissue
Simple squamous epithelium
(lung)
Simple cuboidal epithelium
(kidney)
Stratified squamous epithelium
(esophagus)
Layers of
dead cells
Rapidly dividing
epithelial cells
Simple columnar epithelium
(intestine)
Stratified squamous
epithelium (skin)
20.5 Connective tissue binds and supports other
tissues
• The various types of connective tissue consist
of sparse cells in an extracellular gel matrix
– Loose connective tissue
– Fibrous connective tissue
– Adipose tissue
– Cartilage
– Bone
– Blood
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 20-05
Fat
droplets
Cartilageforming
cells
Adipose tissue
Cell
nucleus
Matrix
Cartilage
(at the end of a bone)
Collagen
fiber
Fibrous connective
tissue (forming a
tendon)
Cell
Collagen fiber
Elastic fibers
Central
canal
White blood
cells
Matrix
Red blood
cell
Bone
Plasma
Loose connective
tissue (under the skin)
Blood
Boneforming
cells
20.6 Muscle tissue functions in movement
• Muscle tissue consists of bundles of long cells
called muscle fibers
– Skeletal muscle is responsible for voluntary
body movements
– Cardiac muscle forms the contractile tissue
of the heart
– Smooth muscle moves the walls of internal
organs such as the stomach, bladder, and
arteries
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 20-06
Unit of
muscle
contraction
Muscle
fiber
Muscle
fiber
Junction
between
two cells
Nucleus
Nucleus
Muscle fiber
Nucleus
Cardiac muscle
Skeletal muscle
Smooth muscle
20.7 Nervous tissue forms a communication
network
• Nervous tissue senses stimuli and rapidly
transmits information through the body
• The neuron is the structural and functional unit
of nervous tissue
– Specialized to conduct electrical impulses
– Consists of cell body, axon, and dendrites
– Nourished by supporting cells
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 20-07
Cell body
Nucleus
LM 330
Cell extensions
CONNECTION
20.8 Artificial tissues have medical uses
• Many, but not all, body tissues are
self-repairing
• Artificial tissues can assist in the healing of
tissues that cannot recover on their own
– Skin
– Cartilage, teeth (under study)
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
20.9 Organs are made up of tissues
• Each organ is made of several tissues that
collectively perform specific functions
– In some organs, tissues are arranged in
layers
• An organ performs functions that none of its
component tissues could carry out alone
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 20-09
Lumen
Small intestine
(cut open)
Lumen
Epithelial tissue
(columnar epithelium)
Connective tissue
Smooth muscle
tissue (2 layers)
Connective tissue
Epithelial tissue
20.10 Organ systems work together to perform
life functions
• There are twelve major organ systems in
vertebrate animals
– Digestive system
– Respiratory system
– Circulatory system
– Immune system
– Lymphatic system
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– Excretory system
– Endocrine system
– Nervous system
– Integumentary system
– Skeletal system
– Muscular system
– Reproductive systems
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LE 20-10a
Digestive system
Mouth
Esophagus
Liver
Stomach
Small
intestine
Large
intestine
Anus
LE 20-10b
Respiratory system
Nasal cavity
Larynx
Trachea
Bronchus
Lung
LE 20-10c
Circulatory system
Heart
Blood
vessels
LE 20-10d-e
Immune system
Lymphatic system
Bone marrow
Thymus
Spleen
Lymph nodes
Lymph vessels
LE 20-10f
Excretory system
Kidney
Ureter
Urinary
bladder
Urethra
LE 20-10g
Endocrine system
Pituitary
gland
Thyroid
gland
Thymus
Adrenal
gland
Pancreas
Testis
(male)
Ovary
(female)
LE 20-10h
Nervous system
Brain
Sense
organ
Spinal
cord
Nerves
LE 20-10i
Integumentary system
Hair
Skin
Nails
LE 20-10j
Skeletal
system
Cartilage
Bones
LE 20-10k
Muscular
system
Skeletal
muscles
LE 20-10l
Reproductive system
Male
Female
Prostate
gland
Vas
deferens
Urethra
Penis
Testis
Oviduct
Ovary
Uterus
Vagina
CONNECTION
20.11 New imaging technology reveals the inner
body
• X-Rays
– High-energy radiation passes through soft
tissue
– Hard structures (teeth, bones, tumors) show
up most clearly on film
– Problems: don't show soft tissue, are only 2D, can cause cancer in large doses
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• Computed tomography (CT)
– Computer-assisted X-ray technique
– Produces images of a series of thin cross
sections through the body
– Images can be studied individually or
combined into 3-D views
– Excellent diagnostic tool, especially for
abdomen and brain
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• Magnetic resonance imaging (MRI)
– Uses powerful magnets to align hydrogen
atoms in water
– Allows visualization of soft tissues; dense
structures nearly invisible
• Particularly good for detecting problems in
nervous tissue surrounded by bone
• Magnetic resonance microscopy (MRM)
– Provides three-dimensional images of very
small structures
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• Positron-emission tomography (PET)
– Scanner detects radiation taken up during
metabolism
– Yields information about metabolic
processes at specific locations in the body
– Most valuable for measuring brain activity
• Alzheimer's disease, epilepsy, stroke
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 20-11d
MAX
HEARING
WORDS
SEEING
WORDS
MIN
SPEAKING
WORDS
GENERATING
WORDS
EXCHANGES WITH THE EXTERNAL ENVIRONMENT
20.12 Structural adaptations enhance exchange
between animals and their environment
• An animal must exchange materials with its
environment
– Oxygen and nutrients enter
– CO2 and metabolic wastes exit
– Only molecules dissolved in water can
move across the plasma membrane
• In small, simple animals, each cell has enough
surface area to meet its needs by direct
diffusion and active transport
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 20-12a
Mouth
Diffusion
Diffusion
Gastrovascular
cavity
Two
cell
layers
• Larger, complex animals have less surface
area relative to volume
– Rely on specialized surfaces for exchanging
materials with the environment
• Interstitial fluid provides for indirect
exchange between blood and body cells
• Branching and folding increase surface
area of the lungs, intestines, and kidneys
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 20-12b
Mouth
External environment
CO2 O
2
Food
Animal
Respiratory
system
Digestive
system
Interstitial
fluid
Heart
Nutrients
Circulatory
system
Body
cells
Excretory
system
Intestine
Anus
Unabsorbed
matter (feces)
Metabolic waste
products (urine)
20.13 Animals regulate their internal environment
• The internal environment of a vertebrate is the
interstitial fluid surrounding the cells
• In response to changes in external conditions,
animals regulate their internal environment to
achieve homeostasis, an internal steady state
– Homeostasis is a dynamic state with
constant small fluctuations
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 20-13b
External
environment
Internal
environment
Homeostatic
mechanisms
Small
fluctuations
Large
fluctuations
20.14 Homeostasis depends on negative
feedback
• In negative feedback, a change in a variable
triggers mechanisms that reverse the change
• Negative feedback mechanisms keep internal
variables fairly constant, with small fluctuations
around set points
• In animals, most control centers that maintain
homeostasis are located in the brain
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 20-14
Sweat glands secrete sweat
that evaporates, cooling body
Thermostat in brain
activates cooling
mechanisms
Blood vessels in
skin dilate and
heat escapes
Temperature rises
above normal
Thermostat shuts off
cooling mechanisms
Temperature
decreases
Homeostasis:
Internal body temperature
of approximately 3638C
Temperature
increases
Thermostat shuts off
warming mechanisms
Temperature falls
below normal
Blood vessels in skin
constrict, minimizing
heat loss
Skeletal muscles rapidly
contract, causing shivering,
which generates heat
Thermostat in
brain activates
warming
mechanisms
Animation: Negative Feedback
Animation: Positive Feedback
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings