Transcript chapter28_Animal Tissues and Organ Systems(1

Cecie Starr
Christine Evers
Lisa Starr
www.cengage.com/biology/starr
Chapter 28
Animal Tissues and
Organ Systems
(Sections 28.1 - 28.3)
Albia Dugger • Miami Dade College
28.1 Stem Cells
• Researchers are testing ways to use stem cells to make
tissues that normally do not regenerate
• stem cell
• Cell that can divide to produce more stem cells or
differentiate into specialized cell types
• Embryonic stem cells can produce any cell type in the
body
• After birth, stem cells are less versatile; they produce
fewer cell types
Stem Cell Division and Differentiation
Stem Cell
Division and
Differentiation
cell
type 1
stem
cell
or
stem
cell
cell
type 2
stem
cell
1
2
or
stem
cell
cell
type 3
stem
cell
mitosis
differentiation
Fig. 28.1, p. 449
Stem Cell
Division and
Differentiation
cell
type 1
stem
cell
or
stem
cell
cell
type 2
stem
cell
1
2
or
stem
cell
cell
type 3
stem
cell
mitosis
differentiation
Stepped Art
Fig. 28.1, p. 449
ABC Video: Can Stem Cells Heal Hearts?
ABC Video: Stem Cell Breakthrough
BBC Video: Stem Cells and Magnets Working
Together to Grow Livers
BBC Video: Using Stem Cells to Cure
Deafness
BBC Video: Repairing Damaged Hearts with
Patients’ Own Stem Cells
28.2 Organization of Animal Bodies
• Most animals have four types of tissues organized as organs
and organ systems
• Extracellular fluid serves as the body’s internal environment
• Animal structure is influenced by physical constraints and
evolutionary history
Levels of Organization
• Animal development produces cells of many types
• Cells of different types, with extracellular matrix, form tissues
• Cell junctions connect the cells of a tissue, hold cells in place,
and allow them to cooperate in specific tasks
Tissue Types
• There are four types of tissue in vertebrate bodies:
1. Epithelial tissue covers body surfaces and lines internal
cavities such as the gut
2. Connective tissue holds body parts together and provides
structural support
3. Muscle tissue moves the body or its parts
4. Nervous tissue detects stimuli and relays information
Levels of Organization (cont.)
• Animal tissues are organized into organs: structures with two
or more tissues that carryout specific tasks
• Example: The heart, which contains all four tissue types
• Two or more organs form organ systems that interact
physically and chemically to carry out a common task
• Example: The circulatory system
• Multiple organ systems make up an organism
Levels of Organization
Levels of Organization
A Cell
(muscle
cells)
B Tissue
(cardiac muscle)
C Organ
(heart)
D Organ System
(circulatory system)
E Organism
(human)
Fig. 28.2, p. 450
Levels of
Organization
A Cell
(muscle cells)
Fig. 28.2a, p. 450
Levels of Organization
B Tissue
(cardiac muscle)
Fig. 28.2b, p. 450
Levels of Organization
C Organ
(heart)
Fig. 28.2c, p. 450
Levels of
Organization
D Organ System
(circulatory system)
Fig. 28.2d, p. 450
Levels of
Organization
E Organism
(human)
Fig. 28.2e, p. 450
The Internal Environment
• An animal body consists mainly of water with dissolved salts,
proteins, and other solutes
• Most body fluid resides in cells; the rest is extracellular fluid
• extracellular fluid (ECF)
• Of a multicelled organism, body fluid outside of cells
• Serves as the body’s internal environment
• Provides cells with nutrients and removes wastes
The Internal Environment (cont.)
• In vertebrates, extracellular fluid consists mainly of interstitial
fluid and plasma
• interstitial fluid
• Of a multicelled organism, body fluid in spaces between
cells
• plasma
• Fluid portion of blood
Homeostasis
• Cells can only survive if solute concentrations and
temperature of the internal environment remain within a
narrow range
• Maintaining conditions of the internal environment within this
range is an important part of homeostasis
Evolution of Animal Structure
• An animal’s structure (anatomy) helps determine its functional
traits (physiology)
• An organism’s structural and physiological trait are
determined genetically, and influenced by the environment
• In each generation, traits that best help individuals survive
and reproduce in their environment are preferentially passed
on
Anatomical Solutions
to Physiological Challenges
• Example: Diffusion of
dissolved substances
through extracellular
fluid is limited
• Vertebrates developed
a circulatory system to
transport substances
Anatomical Solutions
to Physiological Challenges
• Example: Gases enter
or leave an animal’s
body by diffusing across
a moist surface
• Lungs provide a moist
surface for gas
exchange inside the
bodies of land animals
Key Concepts
• Organization of Animal Bodies
• In most animal bodies, cells are organized as tissues,
organs, and organ systems
• The structure of animal bodies has been shaped by
natural selection, but because evolution modifies existing
structures, body plans are often less than optimal
ANIMATION: Cell Junctions
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ANIMATION: Organization of Animal Cells
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28.3 Epithelial Tissue
• Most body parts you can see (skin, hair, nails) are epithelial
tissue, or structures derived from it
• Epithelium also lines internal tubes and cavities, such as
blood vessels and gut
• epithelial tissue
• Sheetlike animal tissue that covers outer body surfaces
and lines internal tubes and cavities
General Characteristics
• Epithelium has one free surface that faces either the outside
environment or some internal body fluid
• The other surface secretes a noncellular basement
membrane
• basement membrane
• Secreted layer that attaches an epithelium to an
underlying tissue layer, most often connective tissue
Epithelium and Basement Membrane
Epithelium and Basement Membrane
free surface of a
simple epithelium
basement membrane
(material secreted by
epithelial cells)
underlying connective tissue
Fig. 28.4, p. 452
ANIMATION: Structure of an epithelium
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Epithelial Tissues (cont.)
• Only epithelial tissues have tight junctions, which prevent
fluids from seeping between cells
• Epithelial tissues subject to mechanical stress (e.g. skin) have
adhering junctions, which connect plasma membranes of cells
at distinct points but do not form a tight seal
Three Types of Epithelium
Three Types of Epithelium
Simple squamous epithelium
• Lines blood vessels, the heart,
and air sacs of lungs
• Allows substances to cross
by diffusion
Fig. 28.5a, p. 452
Three Types of Epithelium
Three Types of Epithelium
Simple cuboidal epithelium
• Lines kidney tubules, ducts of
some glands, reproductive tract
• Functions in absorption and
secretion, movement of
materials
Fig. 28.5b, p. 452
Three Types of Epithelium
Three Types of Epithelium
Simple columnar epithelium
• Lines some airways, parts
of the gut
• Functions in absorption and
secretion, protection
mucus-secreting gland cell
Fig. 28.5c, p. 452
Cilia and Microvilli
• Some epithelial cells have projections (cilia or microvilli) at
their free surface
• Cilia in airways move mucus away from the lungs; cilia in
oviducts propel eggs toward the uterus
• Microvilli lining kidneys and small intestine increase
absorption
• microvilli
• Thin projections from the plasma membrane
• Increase the surface area of some epithelial cells
Glands
• Only epithelial tissue contains gland cells, which secrete a
specific substance that functions outside the cell
• Multicellular glands release substances onto the skin, or into
a body cavity or fluid
• exocrine gland
• Gland that secretes milk, sweat, saliva, or some other
substance through a duct
• endocrine gland
• Ductless gland that secretes hormones into a body fluid
Glandular Epithelium
• Milk-producing
mammary glands of a
lactating woman
• Glands and milk ducts
that deliver milk to the
body surface are
epithelial tissue
milk-producing
mammary gland
A
Glandular
Epithelium
milk duct
Fig. 28.6a, p. 453
Example: Poison Glands
• Glandular epithelium of a tropical frog (Dendrobates azureus)
secretes a paralyzing poison
• Pigment-rich skin of all poisonous frogs has vivid colors and
patterns that evolved as a warning signal
• It’s coloration says to predators, “Don’t even think about it”
Poison Glands
Poison Glands
Pore at
the skin
surface
where
mucus is
released
B
mucous gland
poison gland pigmented cell
Fig. 28.6b, p. 453
Epithelial Structures
• Claws, nails, hooves,
fur, hair, beaks, and
feathers are all derived
from specialized
epithelial cells that
produce large amounts
of the protein keratin
Carcinomas: Epithelial Cell Cancers
• Because it divides frequently, epithelium is the animal tissue
most likely to become cancerous
• An epithelial cell cancer is called a carcinoma
• About 95% of skin cancers are carcinomas
• Breast cancers are usually carcinomas of epithelial cells
that line milk ducts, or of breast glandular epithelium
• Most lung cancers arise in the lung’s epithelial lining
ANIMATION: Types of simple epithelium
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