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Tejidos animales y sistemas de
órganos
Homeostasis en animales
 Las partes del cuerpo interaccionan para:
• Coordinar y controlar las partes individuales
• Adquirir y distribuir materiales a las celulas y
disponer de los desperdicios
• Proteger a los tejidos contra heridas y ataques
• Reproducir, alimentar y proteger la progenie en
su desarrollo temprano
• Mantener el ambiente interno (homeostasis)
Organización del cuerpo animal
 Tejido
• Conjunto de celulas que interaccionan y las
sustancias extracelulares que conducen alguna
tarea
 Organo
• Unidad estructural de 2 o mas tejidos
organizados para conducir alguna tarea
 Sistemas de órganos
• 2 o mas organos que interactuan para una tarea
comun
Las células animales se unen mediante varios
tipos de unión celular
 Uniones adherentes
• Mantienen a las celulas unidas en lugares
especificos.
 Uniones estrechas
• Cierran el paso de fluidos entre celula y celula;
esos fluidos son forzados a pasar por el interior
de las celulas.
 Uniones de hendiduras
• Permiten el paso de iones y moleculas pequenas
del citoplasma de una celula al citoplasma de
otra celula adyacente.
Cuatro tipos de tejidos principales en animales
 Tejido epitelial
 Tejido conectivo
 Tejido muscular
 Tejido nervioso
Tejido epitelial
 Epitelio
• Una capa de celulas que cubre la superficie
exterior y recubre los ductos y cavidades internas
del animal.
 Membrana basal
• Una matriz extracelular que adhiere el epitelio al
tejido subyacente.
 Microvellos
• Proyecciones de epitelio absorbente parecidas a
dedos
Superficie del
epitelio simple
Membrana basal
Tejido conectivo subyacente
Fig. 32-3, p. 541
Varios tipos de tejido epitelial
 Varian segun:
• Numero de capas de celulas:
• Simple: una sola capa
• Estratificado: mas de una capa
• Forma de las celulas
• Escamosas o achatadas
• Cuboidal
• Columnar
Epitelio escamoso simple
• A lo largo de vasos
sanguineos, corazón y
pulmones
• Permite el paso de
sustancias por difusión
Fig. 32-4a, p. 541
Epitelio cuboidal simple
• Recubre ductos de algunas
glándulas y oviductos
• Sirve en absorción, secreción y
movimiento de materiales
Fig. 32-4b, p. 541
Epitelio columnar simple
Glándula secretora
• Recubre algunos ductos de
aire y partes del tracto
digestivo
• Sirve en absorción,
secreción, y protección
Fig. 32-4c, p. 541
Glandular Epithelium
 Glands
• Organs that release substances onto the skin, or
into a body cavity or interstitial fluid
 Exocrine glands (glands with ducts)
• Deliver secretions to an external or internal
surface (saliva, milk, earwax, digestive enzymes)
 Endocrine glands (no ducts)
• Secrete hormones which are carried in blood
32.3 Connective Tissues
 Connective tissues consist of cells and the
extracellular matrix they secrete
 Connective tissues connect body parts and
provide structural and functional support to other
body tissues
Soft Connective Tissues
 Loose connective tissue
• Fibroblasts secrete a matrix of complex
carbohydrates with fibers dispersed widely
through the matrix
 Dense connective tissue (dense collagen fibers)
• Dense irregular: Supports skin, internal organs
• Dense regular: Ligaments and tendons
Specialized Connective Tissues
 Cartilage: Rubbery extracellular matrix,
supports and cushions bones
 Adipose tissue: Fat filled cells, stores energy,
cushions and protect organs
 Bone: Rigid support, muscle attachment,
protection, mineral storage, blood production
Connective Tissues
Connective Tissues
Fig. 32-5a, p. 542
Fig. 32-5b, p. 542
Fig. 32-5c, p. 542
Fig. 32-5d, p. 542
Fig. 32-5e, p. 543
Fig. 32-5f, p. 543
Cartilage and Bone Tissue
cartilage at the
end of long bone
compact bone
tissue
spongy bone
tissue
Fig. 32-6, p. 543
A Fluid Connective Tissue
 Blood: Plasma, blood cells and platelets
white
blood
cell
red
blood
cell
platelet
Fig. 32-7, p. 543
32.4 Muscle Tissues
 Muscle tissue is made up of cells that contract
when stimulated, requires ATP energy
Three Types of Muscle Tissues
 Skeletal muscle tissue
• Moves the skeleton (voluntary)
• Long, striated cells with many nuclei
 Cardiac muscle tissue
• Heart muscle (involuntary)
• Striated cells with single nuclei
 Smooth muscle tissue
• In walls of hollow organs (involuntary)
• No striations, single nuclei
32.5 Nervous Tissue
 Nervous tissue
• Consists of specialized signaling cells (neurons)
and cells that support them (neuroglial cells)
 Nervous tissue detects internal and external
stimuli, and coordinates responses to stimuli
Neurons
 Neurons
• Excitable cells with long cytoplasmic extensions
• Send and receive electrochemical signals
 Three types of neurons
• Sensory neurons are excited by specific stimuli
• Interneurons integrate sensory information
• Motor neurons relay commands from brain and
spinal cord to muscles and glands
A Motor Neuron
Coordination of Nervous Tissue
and Skeletal Muscle
32.2-32.5 Key Concepts
Types of Animal Tissues
 Epithelial tissue covers the body’s surface and
lines its internal tubes
 Connective tissue provides support and
connects body parts
 Muscle tissue moves the body and its parts
 Nervous tissue detects internal and external
stimuli and coordinates responses
32.6 Overview of Major Organ Systems
 In vertebrates, organs arise from three
embryonic germ layers
• Ectoderm (outermost layer) forms nervous tissue
and epithelium of skin
• Mesoderm (middle layer) forms muscle,
connective tissue, and lining of body cavities
• Endoderm (innermost layer) forms epithelium of
gut and lungs
Body Cavities and Directional Terms
Body Cavities and Directional Terms
Body Cavities and Directional Terms
cranial cavity
spinal cavity
thoracic cavity
diaphragm
abdominal cavity
pelvic cavity
Fig. 32-11a, p. 546
Dorsal Surface
transverse
midsagittal
ANTERIOR
POSTERIOR
frontal
Ventral Surface
Fig. 32-11b, p. 546
SUPERIOR
(of two body parts,
the one closer to head)
frontal
plane
(aqua)
midsagittal
plane
(green)
ANTERIOR
(at or near
front of
body)
distal (farthest from
trunk or from origin
of a body part)
proximal (closest
to trunk or to
point of origin of
a body part)
POSTERIOR
(at or near
back of body)
INFERIOR
(of two body parts,
the one farthest from head)
transverse
plane
(yellow)
Fig. 32-11c, p. 546
Animation: Human body cavities
Animation: Directional terms and planes
of symmetry
Eleven Vertebrate Organ Systems
Eleven Vertebrate Organ Systems
Integumentary
System
Protects body
from injury,
dehydration, and
some pathogens;
controls its
temperature;
excretes certain
wastes; receives
some external
stimuli.
Nervous
System
Detects external
and internal
stimuli; controls
and coordinates
responses to
stimuli;
integrates all
organ system
activities.
Muscular
System
Moves body
and its internal
parts;
maintains
posture;
generates heat
by increases
in metabolic
activity.
Skeletal
System
Circulatory
System
Endocrine
System
Supports and
protects body
parts; provides
muscle
attachment
sites; produces
red blood cells;
stores calcium,
phosphorus.
Rapidly
transports
many materials
to and from
interstitial fluid
and cells; helps
stabilize
internal pH and
temperature.
Hormonally
controls body
functioning;
with nervous
system
integrates shortand long-term
activities. (Male
testes added.)
Fig. 32-12a, p. 547
Lymphatic System
Respiratory System Digestive System
Collects and
returns some
tissue fluid to
the bloodstream;
defends the body
against infection
and tissue
damage.
Rapidly delivers
oxygen to the
tissue fluid that
bathes all living
cells; removes
carbon dioxide
wastes of cells;
helps regulate
pH.
Ingests food and
water;
mechanically,
chemically breaks
down food and
absorbs small
molecules into
internal
environment;
eliminates food
residues.
Urinary System
Maintains the
volume and
composition
of internal
environment;
excretes excess
fluid and
bloodborne
wastes.
Reproductive System
Female: Produces eggs;
after fertilization, affords
a protected, nutritive
environment for the
development of new
individuals. Male:
Produces and transfers
sperm to the female.
Hormones of both
systems also influence
other organ systems.
Fig. 32-12b, p. 547
Animation: Human organ systems
32.6 Key Concepts
Organ Systems
 Vertebrate organ systems compartmentalize the
tasks of survival and reproduction for the body
as a whole
 Different systems arise from ectoderm,
mesoderm, and endoderm, the primary tissue
layers that form in the early embryo
32.7 Vertebrate Skin—
Example of an Organ System
 Skin is the body’s interface with the environment
• Sensory receptors, barrier against pathogens,
internal temperature control, water conservation
 Vertebrate skin is made up of all four tissue
types arranged in two layers:
• Outer epidermis contain keratinocytes
• Deeper dermis contains nerves, blood and lymph
vessels, hair follicles and glands
Skin Structure
Skin Structure
Skin Structure
hair
epidermis
dermis
hypodermis
oil gland
hair follicle
blood vessels
sensory
neuron
sweat gland
smooth muscle
Fig. 32-13a, p. 548
outer
flattened
epidermal
cells
cells
being
flattened
dividing
cells
dermis
Fig. 32-13b, p. 548
hair’s
cuticle
one hair cell
keratin
macrofibril
keratin
polypeptide
chain
Fig. 32-13c, p. 548
Animation: Structure of human skin
Animation: Hair fine structure
Frog Skin
 Amphibians may have glands that secrete
mucus, distasteful chemicals, or poisons
• Pigmented cells in dermis warn predators
Fig. 32-14b, p. 549
mucous gland
poison gland
pigmented cell
Fig. 32-14b, p. 549
Sunlight and Human Skin
 Melanocytes in skin make a brown pigment
(melanin) which affects skin color and tanning
 Melanin protects against UV radiation
• A little UV promotes vitamin D production
• A lot of UV damages DNA and promotes cancer
32.8 Farming Skin
 Commercially grown skin substitutes are already
in use for treatment of chronic wounds
 Skin may be a source of stem cells that could be
used to grow other organs
32.7-32.8 Key Concepts
A Closer Look at Skin
 Skin is an example of an organ system
 It includes epithelial layers, connective tissue,
adipose tissue, glands, blood vessels, and
sensory receptors
 It helps protect the body, conserve water, control
temperature, excrete wastes, and detect
external stimuli
Animation: Altering hair structure
Animation: Cell junctions
Animation: Functional zones of a motor
neuron
Animation: Muscle tissues
Animation: Organization of animal cells
Animation: Soft connective tissues
Animation: Specialized connective
tissues
Animation: Structure of an epithelium
Animation: Types of simple epithelium
ABC video: A Saving Graft
ABC video: New Hands
Video: Stem Cells