Download Tissues

Tissue: The Living Fabric
Human Anatomy & Physiology, Sixth Edition
4
Tissues
 Groups of cells similar in structure and function
 Four major types
 Epithelial
 Lining & secretory functions
 Connective
 Structural and dispersal functions
 Muscle
 movement
 Nerve
 Rapid coordination of muscles, cognitive and homeostatic
functions
Epithelial Tissue
 Tightly connected by cell-cell adhesions – desomosomes, tight
junctions & adherins junctions
 Form continuous sheets
 Adherent to and supported by underlying basal laminae
 Cells are polarized – apical and basal surfaces
 Avascular but innervated
 Regenerative
Classification of Epithelia
 Layering
 Shape
Epithelia: Tissues composed of epithelial cells
 Lining
 Skin
 Digestive tract
 Exocrine glands
 Epithelial organs
 Lung
 kidney
Epithelia: Simple Squamous
Figure 4.2a
Epithelia: Stratified Squamous
 Thick membrane composed of several layers of cells
 Function in protection of underlying areas subjected to abrasion
 Forms the external part of the skin’s epidermis (keratinized cells),
and linings of the esophagus, mouth, and vagina (nonkeratinized
cells)
Figure 4.2e
Epithelia: Simple Cuboidal
 Single layer of cubelike cells with large, spherical central nuclei
 Function in secretion and absorption
 Present in kidney tubules, ducts and secretory portions of small
glands, and ovary surface
Figure 4.2b
Epithelia: Transitional
 Several cell layers, basal cells are cuboidal, surface cells are dome
shaped
 Stretches to permit the distension of the urinary bladder
 Lines the urinary bladder, ureters, and part of the urethra
Figure 4.2f
Epithelia: Simple Columnar
Figure 4.2c
Epithelia: Pseudostratified Columnar
 Single layer of cells with different heights; some do not reach the
free surface
 Nuclei are seen at different layers
 Function in secretion and propulsion of mucus
 Present in the male sperm-carrying ducts (nonciliated) and trachea
(ciliated)
Figure 4.2d
Glands
 1 or more cells that makes and secretes an aqueous fluid
 Endocrine
 Release material into blood stream
 Secretions include amino acids, proteins, glycoproteins, and
steroids (hormones)
 Exocrine
 Secrete products into a duct of epithelial cells or directly into
target organ (stomach, intestine etc…)
 mucous, sweat, oil, and salivary glands
Exocrine Glands
 Unicellular gland
 goblet cells in stomach
 Multicellular
 composed of a duct and secretory unit
 Classified according to:
 Simple or compound duct type
 Structure of their secretory units
Multicellular Exocrine Glands
Figure 4.3a-d
Modes of Secretion
Merocrine - exocytosis
Holocrine – fragmentation of cells
(e.g., pancreas, sweat, and salivary
glands)
(e.g., sebaceous glands)
Connective Tissue
 4 subcategories
 Fibrous
 Cartilagenous
 Osseous
 Hematopoietic
 Extracellular matrix
 Proteins secreted by connective tissue cells
 Fluid
Connective Tissue Types & Derivation
Fibrous
Figure 4.5
Extracellular Matrices
 Ground substance – unstructured material
between cells
 Proteins
 proteoglycans – protein core with
glycosaminoglycans (GAGs) attached
 GAGs – chondroitin sulfate, keratin
sulfate, heparin, hyaluronic acid
 fibronectin, laminin – attachement
network for cells
 Fluid
 Structural protein fibers – collagen, elastin
Connective Tissue: Loose
Figure 4.8b
Connective Tissue: Loose
Figure 4.8c
Connective Tissue: Loose
Figure 4.8d
Connective Tissue: Dense Regular
Figure 4.8e
Connective Tissue: Dense Irregular
Figure 4.8f
Connective Tissue: Hyaline Cartilage
Figure 4.8g
Connective Tissue: Fibrocartilage
 Matrix similar to hyaline cartilage but less firm with thick
collagen fibers
 Provides tensile strength and absorbs compression shock
 Found in intervertebral discs, the pubic symphysis, and in discs of
the knee joint
Figure 4.8i
Connective Tissue: Elastic Cartilage
 Similar to hyaline cartilage but with more elastic fibers
 Maintains shape and structure while allowing flexibility
 Supports external ear (pinna) and the epiglottis
Figure 4.8h
Connective Tissue: Bone (Osseous Tissue)
Figure 4.8j
Connective Tissue: Blood
Figure 4.8k
Blood Extracellular Matrix Components
 H2O
 Proteins
 Serum albumin
 Apolipoproteins, HDL, & LDL
 Complement proteins
 Immunoglobulins (antibodies)
 Clotting factors
Neural Tissue
 Neurons
 Conductive cells
 Soma, Axon, Dentrites
 Schwann cells
 Insulating cells
 Glia
 Supporting cells
Nervous (Neural) Tissue
glial cells
Figure 4.10
Muscle Tissue
 Striated (skeletal)
 Long, cylindrical, multinucleate cells
 Striations due to alignment of contractile proteins
 Cardiac
 Branching, striated, uninucleate cells that interlock
 Smooth
 Sheets of spindle-shaped, uninucleate cells without visible
striations
Muscle Tissue: Skeletal
 Long, cylindrical, multinucleate cells with obvious striations
 Initiates and controls voluntary movement
 Found in skeletal muscles that attach to bones or skin
Figure 4.11a
Muscle Tissue: Cardiac
 Branching, striated, uninucleate cells interdigitating at
intercalated discs
 Propels blood into the circulation
 Found in the walls of the heart
Figure 4.11b
Muscle Tissue: Smooth
Figure 4.11c
Developmental Aspects
 Cellular differentiation
 Primary germ layers
 ectoderm
 mesoderm
 endoderm
 Primary cell types interact - induction
 1st Ectoderm + Endoderm  mesoderm
 2nd Mesoderm + Ectoderm  neural tissue
 Subsequent inductions give rise to all other tissue types
Developmental Aspects
Ectoderm
Mesoderm
Endoderm
& Endothelium
Figure 4.13