Tejidos animales y sistemas de órganos
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Transcript of 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
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
Fig. 32-4a, p. 541
Epitelio escamoso simple
• A lo largo de vasos sanguineos, corazón y pulmones
• Permite el paso de sustancias por difusión
Fig. 32-4b, p. 541
Epitelio cuboidal simple
• Recubre ductos de algunas glándulas y oviductos
• Sirve en absorción, secreción y movimiento de materiales
Fig. 32-4c, p. 541
Epitelio columnar simple Glándula secretora
• Recubre algunos ductos de aire y partes del tracto digestivo
• Sirve en absorción, secreción, y protección
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
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
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
Fig. 32-11a, p. 546
cranial cavity
spinal cavity
thoracic cavity
diaphragm
abdominal cavity
pelvic cavity
Fig. 32-11b, p. 546
Dorsal Surface
transverse
midsagittal
ANTERIOR POSTERIOR
frontal
Ventral Surface
Fig. 32-11c, p. 546
SUPERIOR (of two body parts,
the one closer to head)distal (farthest from trunk or from origin of a body part)
frontal plane (aqua)
midsagittal plane (green)
proximal (closest to trunk or to point of origin of a body part)
ANTERIOR (at or near front of body) POSTERIOR
(at or near back of body)
transverse plane (yellow)INFERIOR
(of two body parts, the one farthest from head)
Fig. 32-12a, p. 547
Integumentary System
Nervous System
Muscular System
Skeletal System
Circulatory System
Endocrine System
Protects body from injury, dehydration, and some pathogens; controls its temperature; excretes certain wastes; receives some external stimuli.
Detects external and internal stimuli; controls and coordinates responses to stimuli; integrates all organ system activities.
Moves body and its internal parts; maintains posture; generates heat by increases in metabolic activity.
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 short- and long-term activities. (Male testes added.)
Fig. 32-12b, p. 547
Lymphatic System Respiratory System Digestive System Urinary System Reproductive 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.
Maintains the volume and composition of internal environment; excretes excess fluid and bloodborne wastes.
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.
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
Fig. 32-13a, p. 548
hair
epidermis
dermis
hypodermis
sensory neuronoil gland
hair follicle sweat gland
blood vessels smooth muscle
Frog Skin
Amphibians may have glands that secrete mucus, distasteful chemicals, or poisons• Pigmented cells in dermis warn predators
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