Human Anatomy Chapter 4

Front 1

Tissues

Back 1

Groups of cells similar in structure and function

Front 2

The four types of tissues

Back 2

 Epithelial
 Connective
 Muscle
 Nerve

Front 3

Epithelial Tissue

Back 3

 Cellularity – composed almost entirely of cells
 Special contacts – form continuous sheets held together by tight junctions and desmosomes
 Polarity – apical and basal surfaces
 Supported by connective tissue – reticular and basal laminae
 Avascular but innervated – contains no blood vessels but supplied by nerve fibers
 Regenerative – rapidly replaces lost cells by cell division

Front 4

Classification of Epithelia

Back 4

 Simple or stratified – number of layers
 Squamous, cuboidal, or columnar – shape of cell

Front 5

Epithelia: Simple Squamous

Back 5

 Single layer of flattened cells with disc-shaped nuclei and sparse cytoplasm
 Functions
 Diffusion and filtration
 Provide a slick, friction-reducing lining in lymphatic and cardiovascular systems
 Present in the kidney glomeruli, lining of heart, blood vessels, lymphatic vessels, and serosae

Front 6

Epithelia: Simple Cuboidal

Back 6

 Single layer of cube-like 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

Front 7

Epithelia: Simple Columnar

Back 7

 Single layer of tall cells with oval nuclei; many contain cilia
 Goblet cells are often found in this layer
 Function in absorption and secretion
 Nonciliated type line digestive tract and gallbladder
 Ciliated type line small bronchi, uterine tubes, and some regions of the uterus
 Cilia help move substances through internal passageways

Front 8

Epithelia: Pseudostratified Columnar

Back 8

 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)

Front 9

Epithelia: Stratified Squamous

Back 9

 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)

Front 10

Epithelia: Stratified Cuboidal and Columnar
 Stratified cuboidal

Back 10

 Quite rare in the body
 Found in some sweat and mammary glands
 Typically two cell layers thick

Front 11

Epithelia: Stratified Cuboidal and Columnar
 Stratified columnar

Back 11

 Limited distribution in the body
 Found in the pharynx, male urethra, and lining some glandular ducts
 Also occurs at transition areas between two other types of epithelia

Front 12

Epithelia: Transitional

Back 12

 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

Front 13

Epithelia: Glandular

Back 13

 A gland is one or more cells that makes and secretes an aqueous fluid
 Classified by:
 Site of product release – endocrine or exocrine
 Relative number of cells forming the gland – unicellular or multicellular

Front 14

Endocrine Glands

Back 14

 Ductless glands that produce hormones
 Secretions include amino acids, proteins, glycoproteins, and steroids

Front 15

Exocrine Glands

Back 15

 More numerous than endocrine glands
 Secrete their products onto body surfaces (skin) or into body cavities
 Examples include mucous, sweat, oil, and salivary glands
 The only important unicellular gland is the goblet cell
 Multicellular exocrine glands are composed of a duct and secretory unit

Front 16

Multicellular Exocrine Glands

Back 16

 Classified according to:
--- Simple or compound duct type
--- Structure of their secretory units

Front 17

Modes of Secretion

Back 17

 Merocrine – products are secreted by exocytosis (e.g., pancreas, sweat, and salivary glands)
 Holocrine – products are secreted by the rupture of gland cells (e.g., sebaceous glands)
 Apocrine – products are secreted by release of the tip (apex) of the cell

Front 18

Connective Tissue

Back 18

Found throughout the body; most abundant and widely distributed in primary tissues
 Connective tissue proper
 Cartilage
 Bone
 Blood

Front 19

Functions of Connective Tissue

Back 19

 Binding and support
 Protection
 Insulation
 Transportation

Front 20

Characteristics of Connective Tissue

Back 20

Connective tissues have:
 Mesenchyme as their common tissue of origin
 Varying degrees of vascularity
 Nonliving extracellular matrix, consisting of ground substance and fibers

Front 21

Structural Elements of Connective Tissue

Back 21

 Ground substance – unstructured material that fills the space between cells
 Fibers – collagen, elastic, or reticular
 Cells – fibroblasts, chondroblasts, osteoblasts, and hematopoietic stem cells

Front 22

Ground Substance

Back 22

 Interstitial (tissue) fluid
 Adhesion proteins – fibronectin and laminin
 Proteoglycans – glycosaminoglycans (GAGs)
Functions as a molecular sieve through which nutrients diffuse between blood capillaries and cells

Front 23

Fibers

Back 23

 Collagen – tough; provides high tensile strength
 Elastic – long, thin fibers that allow for stretch
 Reticular – branched collagenous fibers that form delicate networks

Front 24

Cells
(connective tissue)

Back 24

 Fibroblasts – connective tissue proper
 Chondroblasts – cartilage
 Osteoblasts – bone
 Hematopoietic stem cells – blood
 White blood cells, plasma cells, macrophages, and mast cells

Front 25

Connective Tissue: Embryonic

Back 25

 Mesenchyme – embryonic connective tissue
 Gel-like ground substance with fibers and star-shaped mesenchyme cells
 Gives rise to all other connective tissues
 Found in the embryo

Front 26

Connective Tissue Proper: Loose

Back 26

 Areolar connective tissue
 Adipose connective tissue
 Reticular connective tissue

Front 27

Areolar connective tissue

Back 27

 Gel-like matrix with all three connective tissue fibers
 Fibroblasts, macrophages, mast cells, and some white blood cells
 Wraps and cushions organs
 Widely distributed throughout the body

Front 28

Adipose connective tissue

Back 28

 Matrix similar to areolar connective tissue with closely packed adipocytes
 Reserves food stores, insulates against heat loss, and supports and protects
 Found under skin, around kidneys, within abdomen, and in breasts
 Local fat deposits serve nutrient needs of highly active organs

Front 29

Reticular connective tissue

Back 29

 Loose ground substance with reticular fibers
 Reticular cells lie in a fiber network
 Forms a soft internal skeleton, or stroma, that supports other cell types
 Found in lymph nodes, bone marrow, and the spleen

Front 30

Connective Tissue Proper: Dense Regular

Back 30

 Parallel collagen fibers with a few elastic fibers
 Major cell type is fibroblasts
 Attaches muscles to bone or to other muscles, and bone to bone
 Found in tendons, ligaments, and aponeuroses

Front 31

Connective Tissue Proper: Dense Irregular

Back 31

 Irregularly arranged collagen fibers with some elastic fibers
 Major cell type is fibroblasts
 Withstands tension in many directions providing structural strength
 Found in the dermis, submucosa of the digestive tract, and fibrous organ capsules

Front 32

Connective Tissue: Hyaline Cartilage

Back 32

 Amorphous, firm matrix with imperceptible network of collagen fibers
 Chondrocytes lie in lacunae
 Supports, reinforces, cushions, and resists compression
 Forms the costal cartilage
 Found in embryonic skeleton, the end of long bones, nose, trachea, and larynx

Front 33

Connective Tissue: Elastic Cartilage

Back 33

 Similar to hyaline cartilage but with more elastic fibers
 Maintains shape and structure while allowing flexibility
 Supports external ear (pinna) and the epiglottis

Front 34

Connective Tissue: Fibrocartilage Cartilage

Back 34

 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

Front 35

Connective Tissue: Bone (Osseous Tissue)

Back 35

 Hard, calcified matrix with collagen fibers found in bone
 Osteocytes are found in lacunae and are well vascularized
 Supports, protects, and provides levers for muscular action
 Stores calcium, minerals, and fat
 Marrow inside bones is the site of hematopoiesis

Front 36

Connective Tissue: Blood

Back 36

 Red and white cells in a fluid matrix (plasma)
 Contained within blood vessels
 Functions in the transport of respiratory gases, nutrients, and wastes

Front 37

Nervous Tissue

Back 37

 Branched neurons with long cellular processes and support cells
 Transmits electrical signals from sensory receptors to effectors
 Found in the brain, spinal cord, and peripheral nerves

Front 38

Muscle Tissue: Skeletal

Back 38

 Long, cylindrical, multinucleate cells with obvious striations
 Initiates and controls voluntary movement
 Found in skeletal muscles that attach to bones or skin

Front 39

Muscle Tissue: Cardiac

Back 39

 Branching, striated, uninucleated cells interlocking at intercalated discs
 Propels blood into the circulation
 Found in the walls of the heart

Front 40

Muscle Tissue: Smooth

Back 40

 Sheets of spindle-shaped cells with central nuclei that have no striations
 Propels substances along internal passageways (i.e., peristalsis)
 Found in the walls of hollow organs

Front 41

Tissue Trauma

Back 41

Causes inflammation, characterized by:
 Dilation of blood vessels
 Increase in vessel permeability
 Redness, heat, swelling, and pain

Front 42

Epithelial Membranes:Cutaneous Membrane

Back 42

 Cutaneous – skin

Front 43

Epithelial Membranes: Mucous Membrane

Back 43

 Mucous – lines body cavities open to the exterior
(e.g., digestive and respiratory tracts)
 Serous – moist membranes found in closed ventral body cavity

Front 44

Tissue Repair

Back 44

 Organization and restored blood supply
 The blood clot is replaced with granulation tissue
 Regeneration and fibrosis
 Surface epithelium regenerates and the scab detaches
 Fibrous tissue matures and begins to resemble the adjacent tissue
 Results in a fully regenerated epithelium with underlying scar tissue