week 4&5 a&P and lab

common features of epithelial tissue

cellularity, polarity, attachment to a basement membrane

tissues

Groups of cells with a common structure and function.

dense connective tissues

Locations: between skeletal muscles and skeleton, between bones, covering muscles, capsules of internal organs; functions: provides firm attachment, conducts muscle pull, reduces friction, stabilizes bone position

three types of fibers in connective tissue that provide support

collagen - provides high tensile strength elastic fibers - networks of long, thin, elastin fibers that allow for stretch and recoil reticular - short, fine, highly branched collagenous fibers (different chemistry and form than collagen fibers)that provide flexibility.

epithelial secretions

Some epithelial cells are specialized to produce and release secretions. These cells form glands. Glands may be individual cells scattered among other cell types in an epithelium (e.g., goblet cells) or arranged in small, organized clusters within a multicellular gland

ciliated pseudostratified columnar epithelium

Structure Single layer of cells with varying heights; all cells connect to the basement membrane, but not all cells reach the apical surface; has goblet cells and cilia Function Protection; also involved in movement of mucus across surface by ciliary action Location Lining of the larger airways of respiratory tract, including nasal cavity, part of pharynx, larynx, trachea, and bronchi

bone connective tissue

compact bone and spongy bone cells: osteoblasts, osteocytes matrix: Gell like ground substance calcified with inorganic salts. Fibers: collagen features: hard tissue that resists both compression and tension. functions in support

selective permeability of epithelial

an epithelium typically exhibits a range of permeability; it may be relatively non permeable to some substances, while promoting and assisting the passage of other ions and molecules. all substances that enter or leave the body must pass through an epithelium, and this epithelial cells act as "gatekeepers"

Glands

are derived from epithelia, but secretory cells predominate; there are two types: exocrine glands and endocrine glands

epithelia polarity

An epithelium has an apical (āp′i-k ăl) surface (free, or superficial), which is exposed either to the external environment or to some internal body space. The apical surface may have either microvilli or cilia. Also, each epithelium has a basal surface where the epithelium is attached to a basement membrane with underlying connective tissue

characteristics of epithelia

Cellularity (cell junctions) Polarity (apical and basal surfaces) Attachment (basement membrane or basal lamina) Avascularity Regeneration is composed mostly of cell, it exhibits its polarity, and the lateral surfaces of the cells are connected by membrane junctions

epithelia

Cover exposed surfaces and line internal cavities and passageways

individual body cells are specialized

Each type performs specific functions that maintain homeostasis due to similar patterns of gene expression - almost all cells have all your genes, they just express different ones at different times

epithelia cellularity

Epithelial tissue is composed almost entirely of tightly packed cells. There is a minimal amount of extracellular matrix between the cells.

epithelial sensations

Epithelial tissues are innervated by sensory nerve endings to detect or respond to a stimulus. These nerve endings—and those in the underlying connective tissue—continuously relay sensory input to the central nervous system (i.e., brain and spinal cord) concerning touch, pressure, temperature, and pain. Additionally, several organs contain a specialized epithelium, called a neuroepithelium, that houses specific cells responsible for the senses of sight, taste, smell, hearing, and equilibrium

loose connective tissue

areolar, adipose, reticular cells - fibroblasts, fibrocytes, defense cells adipocytes matrix- gel like ground substance. All three fiber types: collagen, reticular, elastic features: six different types; vary in density and types of fibers functions as binding tissue, resists mechanical stress, particularly tension, provides reservoir for water and salts

why does an epithelium need to be highly regenerative

because it is a tissue that is often exposed to the environment and lost by abrasion and damage.

blood connective tissue

blood vessels cells: erythrocytes (RBC), Leukocytes (WBC), platelets matrix: plasma, no fibers features: a fluid tissue, functions to carry O2, CO2, nutrients, wastes, and other substances (hormones, for example)

multicellular exocrine glands

composed of a duct and a secretory unit. usually surrounded by supportive connective tissue, supplies blood and nerve fibers, extends into and divides gland into lobes

stratified epithelium

contains two or more layers of epithelial cells. only the cells in the deepest (basal) layer are in direct contact with the basement membrane. think of bricks

epithelial tissues include

epithelia and glands

epithelial basement membrane

epithelial layer is bound at its basal surface to a thin basement membrane. It may be seen as a single noncellular (or molecular) layer using the light microscope—however, in reality it consists of three molecular layers that can be viewed using an electron microscope: the lamina lucida, the lamina densa, and the reticular lamina

Four types of animal tissue

epithelial, connective, muscle, nervous

three characteristics make connective tissues different from other primary tissues

have mesenchyme (an embryonic tissue) as their common tissue of origin. have varying degrees of vascularity (blood vessels) have nonliving extracellular matrix (ground substance +fibers) between cells

cartilage connective tissue

hyaline, elastic, fibrocartilage cells - chondroblasts found in growing cartilage, chondrocytes Matrix - gel like ground substance, fibers: collagen, elastic fibers in some features: resists compression because of the large amounts of water held in the matrix. functions to cushion and support body structures

-blast (cells of connective tissues)

immature form; mitotically active; secrete ground substance and fibers (called hematopoietic stem cells in bone marrow)

epithelium

is composed of one or more layers of closely packed cells, and it contains little to no extracellular matrix between these cells. Epithelial tissue covers the body surfaces, lines the body cavities and organ cavities, and forms glands.

2. loose connective tissue

locations: beneath dermis of skin, digestive tract, respiratory and urinary tracts; between muscles; around blood vessels, nerves, and around joints functions: cushions organs; provides support but permits independent movement; phagocytic cells provide defense against pathogens

connective tissue proper

loose connective tissue and dense connective tissue

-"Cyte" (cells of connective tissue)

mature form; maintain matrix

cilia

numerous, slightly longer, membranous projections that move fluid, mucus, and materials past the cell surface. Hairlike

simple epithelium types

one layer of cells simple squamous - 1 layer flattened cells simple cuboidal - 1 layer tall aas wide simple columnar - 1 layer of tall, narrow cells pseudostratified columnar - 1 layer tall cells that appears stratified

simple epithelium

one layer of cells and all of the epithelial cells are in direct contact with the basement membrane. found where stress is minimal and filtration, absorption, or secretion is the primary function

gland

one or more cells that make and secrete a particular product classified by: site of product release -endocrine or exocrine relative number of cells forming the gland - (eg noble cells) or multicellular

functions of epithelial tissue

physical protection, selective permeability, secretions, sensations

physical protection of epithelia

protect exposed and internal surfaces from abrasion, dehydration, & destruction by chemical or biological agents

functions of connective tissues

provide protection, bind body tissues together, support the body form most rigid to most flexible: bone-cartilage-dense connective tissue-loose connective tissue - blood

dense connective tissue

regular, irregular, elastic cells - fibroblasts, fibrocytes, defense cells adipocytes matrix- gel like ground substance. All three fiber types: collagen, reticular, elastic features: six different types; vary in density and types of fibers functions as binding tissue, resists mechanical stress, particularly tension, provides reservoir for water and salts

endocrine glands

secrete hormones or precursors into the interstitial fluid, usually for distribution by the bloodstream. ductless glands secrete (by exocytosis) hormones that travel through lymph or blood to their specific target organs -> target organs respond in some characteristic way.

exocrine glands

secrete onto external surfaces or into internal passageways (ducts) that connect to the exterior. exocrine glands: secretions released into ducts; distributed on Body surfaces or into body cavities multicellular examples include sweat, oil and salivary glands unicellular examples are mucous and goblet cells (found in epithelial linings of intestinal and respiratory tracts) all produce mucin (dissolves in water to form mucus)

microvilli

small, membranous projections on the apical surface of the cell that increase its surface area for secretion and absorption

epithelia classification of shape

squamous cells, cuboidal cells, columnar cells and ***transitional

nonciaiated simple columnar epithelium

structure - single layer of cells taller than they are wide; oval shaped nucleus function - absorption and secretion; secretion of mucin location - inner lining of most of digestive tract (stomach, small intestine, and large intestine)

ciliated simple columnar epithelium

structure: single layer of ciliated column like cells with oval nuclei near base of cells; goblet cells location: small tubes of respiratory tract, uterus, paranasal sinuses, central canal of spinal cord, ventricles of brain function: beat in unison moving mucus and foreign particles to be sent out of the body

histology

study of tissues (specimen is fixed, cut, and stained)

epithelia are classified by

the number of cell layers the cell shape at the surface

stratified epithelium types

*stratified squamous - multiple layers upper layer of flattened cells *stratified cuboidal -2 or more layers; cells about as tall as wide stratified columnar - 2 or more layers of tall narrow cells Transitional - multiple layers of cells that change shape when stretched

simple cuboidal epithelium

*structure - single layer of cells about as tall as they are wide; spherical and centrally located nucleus *function- absorption and secretion; forms secretory tissue of most glands and small ducts *location - kidney tubules, thyroid gland follicles; surface of ovary; secretory regions and ducts of most glands

simple squamous epithelium

*structure - single layer of thin, flat cells resembling irregular floor tiles; the single nucleus *function - thinnest barrier allow for rapid diffusion and filtration; secretion in serous membranes *location - air sacs in lungs (alveoli); lining of the lumen of blood vessels, lymph vessels (endothelium); serous membranes of body cavities (mesothelium)

pseudostratified

aka false layer. appears layered (stratified) because the cells nuclei are distributed at different levels between the apical and basal surface. (type of simple epithelium because all the cells are attached to the basement membrane

adipose tissue

deep to the skin, especially at sides, buttocks, breasts; padding round eyes and kidneys functions: provides padding and cushions shocks; insulates (reduces heat loss); stores energy reserves

Classification of epithelia

each epithelium is given two names the first indicates (1) how many cell layers and the second (2)describes the shape of the cell they are either simple or stratified. but also pseudostratified

connective tissues

tissue that connects, supports, binds, or separates other tissues or organs, typically having relatively few cells embedded in an amorphous matrix, often with collagen or other fibers, and including cartilaginous, fatty, and elastic tissues. loose connective tissue - acts as padding under skin bone and cartilage - bone and cartilage are connective tissues made up of cells in a hard or stiff extracellular matrix blood - is a connective tissue made up of cells in a liquid matrix

ground substance of connective tissue

unstructured nonliving material that fills space between cells. it is a medium through which solutes diffuse between blood capillaries and cells components: interstitial fluid, cell adhesion proteins (glue for attachment), proteoglycans (affect viscosity)