Tissues Chapter 4

What Are Tissues? Groups of cells with the same structure and general function. Four types of tissues: 1. Epithelial 2. Connective 3. Muscle 4. Nervous All are surrounded by non-living, intercellular material: MATRIX

Tissue Types TypeDescriptionLocation NervousExcitable cells specialized for rapid communication with other cells Brain, spinal cord, nerves MuscularElongated, excitable cells specialized for contraction Skeletal, cardiac, and smooth ConnectiveLots of matrix, supports, protects and binds together Tendons, ligaments, blood, cartilage, bone and lymph EpithelialLittle matrix, closely packed, covers surfaces or lines cavities Epidermis, lining digestive tract, liver and all glands

Epithelial Tissue Functions: Covers and protects body surfaces internal and external; secretion, absorption, and excretion. Physical Characteristics: - tightly packed, readily divide - anchored by a non-living Basement Membrane to the adjoining tissue layer. Lacks blood vessels so nutrients diffuse from adjacent connective tissue

Locations where found: - skin (epidermis) - Lining of digestive, urinary, reproductive, respiratory tracts. - Lining body cavities - Lining fluid filled cavities in brain - Lining of blood vessels and heart - Covering organs “Apical region” “Basal region”

Classification of Epithelial Tissues Number of cell layers: 1. simple means a single layer of cells. 2. stratified means several cell layers. Shape of the cells: 1. squamous – flat, tile-like 2. cuboidal – cube shape 3. columnar – tall and cylindrical 4. transitional – change shape when under tension

Filtration, osmosis, diffusion Lung alveoli, capillary walls, lines body cavities Nuclei are central and round Secretion and absorption Kidney tubules, thyroid, and smaller exocrine glands

Absorption, secretion, protection, Lines digestive tract and uterus Protection, secretion, mucus movement, Lines respiratory passages Can be ciliated or have microvilli! Ciliated!

Protection, secretion, excretion Skin, oral cavity, throat, anal canal, and vagina. Lines larger exocrine glands: mammary, sweat, salivary Protection, secretion, excretion

Distensibility, protection, lines bladder and urethra Urethra, vas deferens, pharynx Protection and secretion

Glandular Epithelium Most glands are exocrine Secrete to internal or external surface Exocrine glands have ducts and are lined with simple cuboidal cells. Endocrine are ductless and they secrete directly into lymph fluid or bloodstream.

Comparing Endocrine and Exocrine

Type of Exocrine Glands

Connective Tissues Section 5.3

General Characteristics Most abundant tissue in body Rich blood supply (except for cartilage) Nerve supply (except for cartilage) Never exposed to the environment! 2 Basic Components: 1. Specialized cells 2. Matrix (intercellular material) a. Ground substance (liquid to solid) b. Fibers

General Functions 1.Support and protection 2.Binds tissues/organ 3.Transport of materials 4.Store energy 5.Insulation 6.Defense 7.Damage repair

Specialized Cells Fibroblasts – most common, secrete fibers and G.S. into matrix. Fiber types: 1. Collagenous (parallel bundles, strength) 2. Elastic (elastin, stretchy, branching) 3. Reticular (thin, branching, Basement Mem.) Macrophages – wandering monocytes, phagocytes Plasma cells – produces antibodies, B-lymphocytes Adipocytes – cells that store triglycerides (fat molecules) Mast cells – large, release Heparin and Histamine substances. Melanocytes – production of melanin pigment

Group #1: Connective Tissue Proper

Areolar (Loose) Locations: multiple locations including under epithelial tissue of skin, mesentaries Functions: provides nutrients and support to other tissue types; immune functions; protection Key Features: loose, scattered fiber appearance, multiple fiber and cell types

Adipose Locations: subcutaneous region, bone marrow, around viscera and joints, behind eyeball in socket Functions: lipid storage; thermoregulation; protection (padding) Key Features: cells with nuclei "pushed to the side"; minimal matrix; white and brown types

Dense or Collagenous Locations: tendons, ligaments, aponeuroses, sclera (white of eye) Function: strong support Key Features: matrix is shiny and white, one fiber type in parallel arrangement; thin fibroblasts; minimal ground substance

Dense (Irregular) Locations: dermis of skin; periosteum, fascia, pericardium, perichondrium and organ capsules. Function: strong support, resists pulling from all directions Key Features: thick bundles of fibers with no pattern, minimal ground substance

Group #2: Specialized Connective Tissues

Cartilage – Chondrocytes; collagenous fibers, lacunae, and avascular Types: 1. Hyaline – fine fibers, most common 2. Elastic – thicker with most flexiblity 3. Fibrocartilage – thick collagen fibers Bone – osteocytes; mineral deposits and collagen fibers Blood – plasma (clear matrix) with formed elements (RBC, WBC, platelets)

Hyaline Cartilage Locations: fetal skeleton; covering of bones at joints; ends of ribs, nose, tracheal rings, part of larynx Function: flexible support, smooth movements at joints Key Features: bluish/white, glassy appearance; chondrocytes in lacunae

Elastic Cartilage Locations: outer ear; epiglottis; eustachian tube, part of larynx Function: flexible support, strength, maintains shape Key Features: single chondrocytes in lacunae; random elastic fibers look hairy

Fibrocartilage Locations: intervertebral discs, pubis symphysis, meniscus Function: very firm support, shock absorption Key Features: collagen fiber bundles, small chondrocytes, no perichondrium

Bone Locations: all bones, spongy and compact Function: support, blood cell production, energy storage, protection, levers for muscles Key Features: rings of bone (Osteons), solid G.S. with minerals, collagen for flexibility

Blood Locations: within blood vessels (arteries, veins, and capillaries), bone marrow, and heart chambers Functions: transportation of O 2 and CO 2, immunity, clotting Key Features: liquid G.S., RBC’s with doughnut appearance, WBC’s have nuclei, platelets tiny fragments