Tejidos animales y sistemas de rganos Homeostasis en

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 -4 a, p. 541

Epitelio cuboidal simple • Recubre ductos de algunas glándulas y oviductos • Sirve en absorción, secreción y movimiento de materiales Fig. 32 -4 b, 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 -4 c, 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 -5 a, p. 542

Fig. 32 -5 b, p. 542

Fig. 32 -5 c, p. 542

Fig. 32 -5 d, p. 542

Fig. 32 -5 e, p. 543

Fig. 32 -5 f, 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 -11 a, p. 546

Dorsal Surface transverse midsagittal ANTERIOR POSTERIOR frontal Ventral Surface Fig. 32 -11 b, 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 -11 c, 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 p. H and temperature. Hormonally controls body functioning; with nervous system integrates shortand long-term activities. (Male testes added. ) Fig. 32 -12 a, 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 p. H. 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 -12 b, 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 hypodermis oil gland hair follicle blood vessels sensory neuron sweat gland smooth muscle Fig. 32 -13 a, p. 548

outer flattened epidermal cells being flattened dividing cells dermis Fig. 32 -13 b, p. 548

hair’s cuticle one hair cell keratin macrofibril keratin polypeptide chain Fig. 32 -13 c, 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 -14 b, p. 549

mucous gland poison gland pigmented cell Fig. 32 -14 b, 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