Matrix
complex extracellular material
Histology
the biology of tissues
Epithelial tissue
-covers and protects the body surface, lines body cavities, specializes in moving substances in and out of body or particular organs
-has very little ECM
-divided into 2 group membranous and glandular epithelium
Connective tissue
-support body and connect and hold them together, transport substances through the body, and protect from foreign invaders
-separated by large quantities of matrix
Muscle tissue
-produces movement
-cells adapted for contractility and produce movement by shortening or lengthening the contractile units
-3 types skeletal, smooth, and cardiac
Nervous tissue
specializes in communication b/w various parts of the body and in integration of activities
-generation of complex messages for coordination of body functions
Primary Germ Layers
-endoderm
-mesoderm
-ectoderm
Histogenesis
-cells in each germ layer become increasing more differentiated to from specific tissues
ECM
-made up of mostly proteins and proteoglycans
-have structural protein fibers like collagen and elastin
-has glycoproteins
Proteoglycans
-hybrid molecules made up mostly of carbohydrates attached to a protein backbone
Membranous epithelium
-covers the body and some of its parts and lines the serous cavities, blood and lymphatic vessels, and respiratory, digestive, and genitourinary tracts
Glandular epithelium
-grouped in solid cords or hollow follicles that form secretory units of endocrine and exocrine glands
Functions of Epithelial
-Protection
-sensory functions
-secretion
-absorption
-excretion
basement Membrane
-epithelial tissue attaches to an underlying layer of connective tissue by means of thin noncellular layer of adhesive, permeable layer
-highly complex structure made up partly of glycoprotein material secreted by the epithelial components and fine mesh o
Avascular
-epithelial tissues contain no blood vessels
desmosomes
plasma membranes are modified to hold cells together
Squamous cells
-cells flat and plate-like
cuboidal cells
-cube-shaped and have more cytoplasm than squamous cells
columnar epithelial
-higher than they are wide and appear narrow and cylindrical
pseudostratified columnar epithelium
-has only one layer of oddly shaped columnar cells
-each cell touches the basement membrane
-some nuclei are near top and some near bottom
-only single layer
simple epithelium
-epithelial cells in a single layer
stratified epithelium
-epithelial cells are layered one on another
transitional epithelium
-unique arrangement of differing cell shapes in a stratified, or layered, epithelial sheet
simple squamous epithelium
-consists of one layer of flat, scalelike cells
-substances can readily diffuse or filter through this type of tissue
-ex alveoli of the lungs
Endothelium
-blood and lymphatic vessel linings
mesothelium
-surfaces of pleura, pericardium and peritoneum
Simple Cuboidal Epithelium
-composed of one layer of cuboidal cells resting on a basement membrane
-seen in many glands and ducts like kidneys
Simple Columnar Epithelium
-composes the surface of mucous membrane that lines the stomach, intestine, uterus, uterine tubes and parts of respiratory tract
-is single layer of cells which have modified structure
-ex Goblet cells, cilia, and microvilli
Goblet cells
-large, secretory vesicles that give them the appearance of a goblet
-contain mucus
Mucus
-a solution of water, electrolytes and proteoglycans
-mixture of mucins which are proteoglycans
Microvilli
-plasma membranes of many columnar cells extend out in hundreds and hundreds of microscopic fingerlike projections
Pseudostratified Columnar Epithelium
-found in lining air passages of respiratory system and certain segments of male reproductive system
-only a single layer of irregularly shaped columnar cells touches the basement membrane
-cells are of differing heights
-goblet cells and cilia are presen
Stratified squamous epithelium
-characterized by multiple layers of cells with typical flattened squamous cells
-has keratin in these cells contributes to protective qualities of skin
Nonkeratinized stratified squamous epithelium
-found lining vagina, mouth, and esophagus
-surface is moist, and outer epithelial cells do not contain keratin
-serves as protection function
stratified cuboidal epithelium
-serves a protective function
-2 or more rows of low cuboidal cells are arranged randomly over a basement membrane
-can be located in sweat gland ducts, in pharynx, and over parts of epiglottis
-only most superficial cells are truly columnar in appearance
Transitional epithelium
-found in body areas subjected to stress and tension changes
-ex Wall of urinary bladder
-as tensions increases, epithelial sheet is expanded, number observable cell layers decreases and it cell shape changes from cuboidal to squamous
Unicellular glands
-glandular epithelial cells that functions singly
Multicellular glands
-glandular cells that function in clusters, solid cords, or hollow follicles
Glands
-classified as either endocrine or exocrine
Exocrine glands
-discharge secretion products into ducts
-ex Salivary glands
Endocrine glands
-ductless glands
-discharge secretion products directly into blood or interstitial fluid
-ex Pituitary, thyroid, and adrenal glands
Tubular Exocrine glands
-shaped like a tube
Alveolar Exocrine glands
-saclike
simple exocrine glands
-have only one duct leading to surface
compound exocrine glands
-have 2 or more ducts leading to surface
Apocrine glands
-collect secretory products near apex or tip of cell and the release them into a duct by pinching off distended end
-Ex mammary glands
Holocrine glands
-collect their secretory product inside the cell and then rupture completely to release it
-Ex sebaceous glands
Merocrine glands
-discharge secretion product directly through the cell or plasma membrane
-ex Salivary gland
Functions of Connective Tissue
-connects
-supports
-transports
-defends
ECM of Connective Tissue
-made up of varying numbers and kinds of fibers, fluid, and ground substance
-qualities of its fibers determine structural characteristics of connective tissue
-has either collagenous, reticular, or elastic fiber
Collagenous Fibers
-made up of collagen
-occurs in bundles, which provide great strength
-sometimes called white fibers
-most abundant protein compounds
Reticular fibers
-occurs in networks
-delicate
-support small structures like capillaries and nerve fibers
-made out of reticulin
Elastic Fibers
-made up of protein called elastin
-returns to original length after being stretches
Fibrous Tissue
-have many fibers in the ECM
Loose Connective Tissue
-called areolar tissue also
-stretchable and most widely distributed of all tissues
-its matrix is soft, thick gel
-fibroblasts are the greatest numbers in this tissue
-macrophages are second
-mast cells also present
Fibroblast
-synthesize gel-like ground substance and fibers present in
Macrophages
-carry on phagocytosis
Mast cells
-capable of releasing a variety of molecules
-released in response to exposure to substances from outside the body and produce an inflammation response
Adipose Tissue
-contains fat cells called adipocytes
-fewer fibroblasts, macrophages, and mast cells
-found in kidneys for support and protection
-constitutes a storage depot for excess food
-acts as insulating material to conserve body heat
Reticular tissue
-3D web
-forms framework of spleen, lymph nodes, and bone marrow
-functions in defense against microorganisms and injurious substances
-filters these harmful substances out of blood and lymph
Dense fibrous tissue
-fibers packed densely in the matrix
-has few fibroblast cells
-2 types regular and irregular
Dense Irregular FIbrous Tissue
-bundles of collagenous fibers intertwine in irregular, swirling arrangements
-forms thick mat of strong connective tissue that can withstand stresses applied from any direction
-found in Kidney and spleen
Dense Regular FIbrous Tissue
-arranged in regular, parallel rows
2 forms of this tissue, collagenous regular fibrous tissue and elastic dense regular fibrous tissue
Collagenous dense regular fibrous tissue
-flexible but possesses great tensile strength when pulled from either or both end
-found in structures that anchor muscle to bone
Elastic dense regular fibrous tissue
-contains mostly elastic fibers
-are in parallel arrangement
-found in walls of arteries
Osseous Tissue
-unique form of hard connective tissue
Osteocytes
-embedded in matrix material containing both collagen fibers and mineral salt crystals
-has calcified matrix
-located in lacunae
-trapped in hard bone matrix
Membrane bones
-formed with membranous tissue
-ex flat bones of skull
Endochondral ossification
-other bones formed indirectly in this replacement of cartilage process
Compact Bone Tissue
-bone tissue that forms hard shell of a bone
Osteon
-basic organizational structural unit of compact bone
-also called Haversian System
Lacunae
-small spaces
-arranged in lamellae
Lamellae
-concentric layers of bone matrix
Canaliculi
-connect each lacuna and osteocyte with nutrient blood vessels
osteoblasts
-bone-forming cells
osteoclast
-bone-destroying cell
-dissolve bone away from mature osteocyte and release it again to become osteoblast
Cancellous bone Tissue
-lattice of thin
-also called spongy bone tissue
-also called trabecular bone
Trabeculae
-thin beams
-form framework that supports the red bone marrow
-give internal support to the bone
Red Bone Marrow
-also called myeloid tissue
-type of reticular tissue that contains the stem cells responsible for producing various types of blood cells
Cartilage Tissue
-has one cell type, chondrocyte
-avascular so nutrients reach cell by diffusion
-movement is through matrix from blood vessels located in perichondrium
-3 types, Hyaline, Fibrocartilage, and elastic
Chondrocyte
-produce fibers and tough rubbery ground substance of cartilage
-found in lacunae
Perichondrium
-connective tissue membrane
-surrounds cartilage mass
Hyaline Cartilage tissue
-low amount of collagen
-has shiny and translucent appearance
-most abundant type of cartilage
-found in respiratory tubes and at ends of bones
Fibrocartilage
-strongest and most durable type of cartilage
-matrix is rigid and filled with dense strong white collagen fibers
-serves as shock absorbers b/w adjacent vertebrae and in knee joint
Elastic Cartilage
-contains few collagen fibers but large number of elastic fibers
-has great flexibility
-Ex external ear, and in larynx
Blood Tissue
-exists in a liquid state
-contains neither ground substance nor fibers
-matrix divided into plasma and formed elements aka the name of the first word of this term cells
-many transport functions
-maintain constant body temperature and regulating pH of bo
Blood cells
-divided into 3 classes, erythrocytes, RBC, leukocytes, WBC, and thrombocytes, platelets
White Blood Cells
-destroy harmful microorganisms
Hematopoietic Tissue
-circulating blood tissue formed here
Skeletal Muscle Tissue
-most of muscle that is attached to bones
-striated voluntary muscle
-have length of more than 3.75 cm
Smooth Muscle Tissue
-also called visceral muscle tissue
-found in stomach, intestines and blood vessels
-non-striated involuntary
Cardiac Muscle Tissue
-makes up wall of heart
-striated involuntary
-have cross striations and unique dark bands
Striated
-cross striations visible on microscopic slides
Voluntary
-willed control of muscle contractions
Nervous tissue
-does rapid communication
-has more developed excitability and conductivity characteristics
-organs of system is brain, spinal cord, and nerves
-2 basic cells neurons and neurologia
Neurons
-nerve cells
-conducting units of system
-characterized by a cell body called soma, axon, and dendrites
Neurologia
-special connecting, protective, and supporting cells
-different types astrocytes, microglia, schwann cells, and oligodendrocytes
-important coordinating roles in nervous system
Axon
-transmits nerve impulses away from cell body
dendrites
-carry nerve signals toward axon
Astrocytes
-form a blood-brain barrier that protects brain tissue from potentially harmful substances in blood
Microglia
-help destroy pathogens and damaged tissue cells in brain
Schwann cells
-electrically insulate axons to increase their speed of conduction
Oligodendrocytes
-electrically insulate axons to increase their speed of conduction
Regeneration
-tissue repair themselves by allowing phagocytic cells to remove dead or injured cells and filling gaps that are left
-in epithelial membrane when cut occurs, cells quickly divide to form daughter cells to fill the wound
-in connective tissue, cells that
Scar
-if in connective tissue, the mass is deep or large or cell damage extensive
Keloid
-unusually thick scar that develops in lower layer of skin
Muscle regeneration
-limited capacity to regenerate itself
-sometimes replaced with fibrous connective tissue instead of this tissue
Nervous tissue regeneration
-limited capacity to regenerate
-neurons can sometimes regenerate but very slowly if certain neuroglia are present
membrane
-sheetlikes structure that has many important functions in the body
-cover and protect body surface, line body cavities, and cover inner surfaces of hollow organs
-some anchor organs to each other or to bones and other cover internal organs
-sometimes sec
Epithelial membranes
-composed of epithelial tissue and underlying layer of connective tissue
-3 types, cutaneous membrane, serous membrane, and mucous membranes
Connective tissue membranes
-composed of types of connective tissue only
Cutaneous membrane
-covers body surfaces that are exposed to external environment
-most largest and visible in body
-16% of body weight
Serous membrane
-lines cavities that are not open to external environment and covers many organs inside cavities
-has 2 layers os tissue, simple squamous epithelium, and other thin connective tissue layer
-secrete thing, watery fluid that lubricates as they rub against o
Mucous membranes
-epithelial membranes that line body surfaces opening directly to exterior
-ex respiratory, digestive, urinary, and reproductive tracts
-epithelial component of membrane varies depending on location
-connective tissue component is lamina propria
-produce
Lamina Propria
-fibrous connective tissue underlying the epithelium in mucous membranes
Synovial Membrane
-lines spaces b/w bones and joints that move
-smooth and slick and secrete a thick colorless lubricating fluid called synovial fluid
-reduce friction b/w opposing surfaces of bones in moveable joints