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Tissues Hierarchy of organization

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Presentation on theme: "Tissues Hierarchy of organization"— Presentation transcript:

1 Tissues Hierarchy of organization
Atoms  molecules  cells  TISSUES  organs  Organ systems  organisms  populations  communities  ecosystems  biosphere Study of tissues = Histology

2 Tissue types * Epithelial tissue Cover exposed surfaces (linings)
both external and internal * Connective tissue Fills internal spaces Connects, supports, transports * Muscle tissue movement Transmission of information * Neural tissue

3 Epithelial tissue Covering of all exposed surfaces Characteristics
Polarity (apical and basal surfaces) Attachment (basement membrane) Tightly bound cells Avascular (nutrients via diffusion) Regeneration (actively in 24° cell cycle)

4 Epithelial tissue Functions Physical protection Control permeability
Sensation Secretion (glands) Exocrine = secretions onto epithelial surface Endocrine = secretions released to surrounding fluids Cilia and microvilli

5 Epithelial connections
Special proteins connect cells to each other at Tight junctions Desmosomes Gap junctions Apical In-between epi cells Keeps fluids from leaking between cells Interlock cells Provide channels Between cells Connect cell to cell Attach to cytoskeleton Basement membrane Holds epithelium to rest of body Proteins and glycoproteins from basal lamina and reticular lamina Epithelium continuously replaced by stem cells near basement layer

6 Epithelium classification
Simple epithelial tissue = single layer of cells Stratified epithelial tissue = stacked cells Cell shapes Squamous cuboidal columnar Box shaped Ducts glands Long and narrow (simple only) Secretion absorption Cilia and microvilli Small intestine Nasal cavity Flat Irregular shape Lining ventral body cavity Mouth Kidney tubules Blood vessels Where thin/permeable required

7 Epithelium and glands Endocrine glands = to follow
Exocrine glands = secrete into ducts Merocrine = secretion via exocytosis mucous Apocrine = secretion with loss of cytoplasm milk Holocrine = secretion with loss of cell sebum

8 Epithelial secretions
Serous secretion = watery with enzymes parotid salivary glands Mucous secretions = watery with glycoproteins for lubrication sublingual salivary glands Mixed secretion = both submandibular salivary glands

9 Connective tissue Connect, support, transport Bone, fat, blood
Characteristics With specialized cells With extracellular proteins With ground substance Proteins + ground substance = extracellular matrix

10 Connective tissue Functions Structural framework Transport (fluids)
Protection (cushion) Support/connect tissues Store energy Defense

11 Connective tissue classification
Connective tissue proper Fluid connective tissue Supporting connective tissue Cellular and matrix content varied Adipose, tendons May be loose or dense Distinct cells in watery matrix Blood, lymph Cartilage, bone

12 Connective tissue PROPER
The CELLS Fibroblasts Macrophages Adipocytes Mesenchymal cells Melanocytes Mast cells Lymphocytes Microphages Always present, secrete hyaluronan to make ground substance, viscous WBCs that engulf pathogens Fat cells Stem cells that produce macrophages, fibroblasts and other connective tissue cells Synthesize/store pigment Release histamine and heparin in response to injury WBCs involved in immune response WBCs involved in protection from pathogens

13 Connective tissue PROPER
The GROUND SUBSTANCE The FIBERS Clear, colorless, viscous Collagen Reticular fibers Elastin fibers Long, straight, unbranched tendons, ligaments Loose connective tissue Adipose, reticular Like collagen but branched Stabilize position of cells Dense connective tissue Tendons, ligaments, surrounding organs Thin, branched Return to original shape

14 FLUID connective tissue
Blood Lymph Erythrocytes (RBCs) Leukocytes (WBCs) Platelets Plasma Lymphocytes Interstitial fluid Hemoglobin ~45% blood volume Immune system Immune system Watery matrix collected from surrounding cells Blood clotting Watery matrix

15 SUPPORTING connective tissue
Cartilage Chondrocytes produce matrix Avascular Perichondrium separates cartliage from other tissue Types of cartilage Hyaline Elastic Fibrocartilage Common Tightly packed collagen Ribs, sternum Nasal, end bones Elastic fibers Epiglottis, Middle ear, Pinna, larynx Interwoven collagen Durable Spinal vertabrae Pelvic bones

16 SUPPORTING connective tissue
Bone Osseous tissue Osteocytes in matrix with calcium salts Covered by periosteum More to follow with skeletal system

17 Connective tissue Membranes Mucous membranes
Line cavities that communicate with exterior Respiratory, digestive, urinary, reproductive Serous membranes Line divisions in ventral body cavity Pleural = pleural cavity Peritoneum = peritoneal cavity Pericardium = pericardial cavity Transudate = fluid on surface of serous membranes

18 Connective tissue Membranes Cutaneous membrane
= skin = covers surface of body Synovial membranes Capsule at articulations (joints) Loose collagen, proteoglycans, glycoproteins Full of synovial fluid

19 Connective tissue layers
Superficial fascia Deep fascia Subserous fascia Subcutaneous/hypodermis Skin/underlying organs Deep connective tissue Organs/muscle Between serous membrane and deep fascia

20 Muscle tissue For MOVEMENT via contraction 3 types of muscle tissue
Skeletal muscle Cardiac muscle Smooth muscle Striated, multi nucleated voluntary movement Heart connected at intercalated discs Nonstriated Involuntary movement MORE TO FOLLOW Muscular system

21 Neural tissue Conduct electrical impulses
Neurons = conduct nerve impulses Glial cells = support neurons MORE TO FOLLOW Nervous system

22 Embryology Zygote undergoes cleavage  morula 
BLASTULA (blastocyst) = hollow ball Gastrulation forms 3 germ layers Ectoderm, mesoderm, endoderm Become different tissues  organ systems (page )

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