anp exam 2

histology and integumentary system

epithelial tissue function

covers body surfaces; lines hollow organs; body cavities and ducts; forms glands

connective tissue function

protects and supports the body and its organs

muscle tissue function

generates forces needed to make body structures move; generates body heat

nervous tissue function

detects and responds to changes in the body’s internal and external environments

primary germ layers

first tissues formed in human embryo; ectoderm, endoderm, and mesoderm

where does the epithelial tissue develop from

develops from all 3 layers: ectoderm, endoderm, and mesoderm

where does connective and (most) muscle tissue develop from

develops from the mesoderm

where does nervous tissue develop from

develops from the ectoderm

structure of epithelial tissue

cells arranged in continuous sheets in single or multiple layers; attached to a basement membrane

how closely are cells arranged in epithelial tissue

cells are closely packed with little intercellular space

characteristics of epithelial tissue

avascular, high rate of cell division, extensive innervation

how is epithelial tissue avascular

lacks its own blood supply, blood vessels are only located in the connective tissue adjacent to the epidermis.

why does epithelial tissue have extensive innervation

contains rich nerve supply that detects environmental stimulus

apical (free) surface

surface of epithelial tissue that faces the body surface, body cavity, the lumen of an organ or tubular duct; may have cilia or microvilli

lateral surfaces

surface of epithelial cells that face adjacent cells on both sides

basal surfaces

surface of epithelial cells that is the deepest layer of cells which adhere to the extracellular materials

basement membrane

thin extracellular layer that serves as a point of attachment and support for overlying epithelial tissue

what are the general functions of epithelial tissue?

contains a selective barrier; releases products produced by the cell; protects against abrasive forces; detects sensations from environmental stimulus; plays a role in protection, filtration, absorption, secretion, and excretion.

2 primary types of epithelial tissue

1) covering and lining epithelium: forms outer covering of the skin and some internal organs

2) glandular epithelium: makes up the “secreting” portion of glands such as adrenal, sweat, and thyroid glands

squamous

flattened irregularly shaped cells; allow rapid passage of substances

cuboidal

cube-shaped cells; function in secretion or absorption

columnar

elongated cells; protect underlying tissues, may have cilia or microvilli

transitional

cells that change shape from flat to cuboidal and back; ex. urinary bladder

simple

single layer of cells

stratified

2 or more layers of cells; protects underlying tissues where abrasive forces exist

pseudostratified

appears to have multiple layers but is truly a simple epithelium; all cells attach to basement membrane, but not all cells reach the apical surface

simple squamous

single layer of flat cells; line heart, blood and lymph vessels and air sacs of lungs to allow for filtration, secretion, diffusion, osmosis

simple cuboidal

single layer of cube-shaped cells; surface of ovary, capsule of lens of eye, lines kidney tubules, and ducts of many glands to allow for secretion and absorption

simple columnar

single layer of elongated cells

nonciliated simple columnar location

line GI tract, ducts, glands, and gallbladder

nonciliated simple columnar function

functions for secretion and absorption

ciliated simple columnar location

lines bronchioles of resp tract, uterine tubes, and uterus;

ciliated simple columnar function

functions to move substances/mucus by ciliary action

pseudostratified columnar location

single layer of cells; but appears to be multiple players; located in airways of resp tract, lines of ducts of glands; can be ciliated or nonciliated

pseudostratified columnar function

functions for secretion and movement of mucus and PROTECTION

stratified squamous

flattened/squamous cells on apical surface and may have cuboidal or columnar cells in deeper layers

nonkeratinized stratified squamous

when apical cells are alive; location: lines oral cavity, esophagus and vaginal cavity

keratinized stratified squamous

apical cells are dead and filled with protein and keratin (STRENGTH); located on epidermis to protect

stratified cuboidal

apical cells are cuboidal over squamous cells; part of ducts of sweat glands and part of male urethra; protect and secrete

stratified columnar

several layers of irregularly shaped cells; only apical layer has elongated cells; protection and secretion; found in parts of urethra and excretory ducts of glands

transitional

vary from flat to cuboidal; lines urinary bladder and portions of ureters and urethra; allows distention and relaxation

what is the structure/location of glandular epithelium cells

lie in clusters deep to the “covering and lining” epithelium

gland

single or group of cells that secrete substances into ducts onto a surface or into the blood

endocrine glands

secrete hormones directly into the interstitial fluid and blood; regulates metabolic and physiological activities to maintain homeostasis

what do endocrine glands lack

they lack ducts (tubes)

exocrine glands

secrete substances into ducts that empty onto the surface of “covering and lining” epithelium (skin surface, lumen of a hollow organ)

secretions include mucus, oil, sweat, earwax, saliva, digestive enzymes

connective tissue consists of 3 basic elements

cells, protein fibers, and ground substance (fibers + ground substance) —> extracellular matrix

what are the 4 types of resident cells (stationary CT cells)

fibroblasts, adipocytes, mesenchymal cells, macrophages

fibroblasts

large, flat, branching cells; usually the most numerous cells in connective tissue; secrete fibers and part of the ground substances of extracellular matrix

adipocytes

fat cells or adipose cells; store triglycerides, found deep to the skin and around organs

mesenchymal cells

embryonic cell; will divide if tissue is damaged

macrophages

derived from white blood cell; phagocytize damaged cells or pathogens

what are the 4 types of wandering connective tissues

mast cells, plasma cells, free macrophages, other leukocytes, (neutrophils and lymphocytes) ALL OF THESE ARE TYPES OF LEUKOCYTES

mast cells

involved in the inflammatory response

plasma cells

produce antibodies: proteins that immobilize foreign material

free macrophages

phagocytic cells that move throughout the tissue

neutrophils

phagocytize bacteria

lymphocytes

attacks and kills foreign materials

extracellular matrix

substance between the cells

what does the extracellular matrix consist of?

ground substance - between cells and fibers

protein fibers - strengthen and support tissue

ground substance

nonliving material produced by CT cells

can be fluid, semifluid, gelatinous, or calcified (contains water and others such as polysaccharides and glycoproteins

functions to support and bind cells together

what are the 3 different types of protein fibers

collagen, elastic, reticular fibers

collagen fibers

found in parallel bundles, very strong and flexible

where are collagen fibers found

found in most CT, especially bones, cartilage, tendons, and ligaments

elastic fibers

contain the protein, elastin; provide strength, stability and elasticity

where are elastic fibers found?

found in skin, blood vessel walls, and lungs

reticular fibers

similar to collagen, but thinner; provide support and strength to certain tissues

stroma

supporting framework of soft organs of spleen and lymph nodes; also in basement membrane; contains reticular fibers

what are embryonic connective tissue

mesenchyme, mucous connective tissue

what are mature connective tissue

loose connective tissue, dense connective tissue, cartilage, bone, blood

mesenchyme CT

first to develop in embryo, gives rise to all other connective tissues

mucous CT

gelatinous substance within the umbilical cord and is a rich source of stem cells

loose connective tissue

supports and surrounds structures and organs, contains few cells, sparse, and irregularly arranged protein fibers and abundant ground substance

3 types of loose connective tissue

areolar, reticular, adipose

adipose connective tissue

most widely distributed CT in body; protects and binds; located in subcutaneous layer of tissue deep to skin, dermis of skin, surrounds organs and nerves

what exactly do adipose CT contain

contains fibroblasts, macrophages, plasma cells, mast cells and adipocytes; contains the 3 types of fibers: collagen, elastic & reticular

reticular connective tissue

contain interlacing reticular fibers, fibroblasts and leukocytes

reticular connective tissue location and function

forms the stroma of liver, spleen, lymph nodes, and bind together smooth muscle cells

adipose connective tissue

functions to support and protect various organs, insulate, major reserve for energy; located in subcutaneous layer, surrounds some organs

adipocytes

specialized cells that store triglycerides…which fills cell and pushes nucleus and cytoplasm to periphery of cell; produced by fibroblasts

dense connective tissue

composed primarily of protein fibers; less ground substance than loose CT

what are the 3 types of dense connective tissue

dense regular, dense irregular, elastic

dense regular connective tissue

consists of collagen fibers in bundles with fibroblasts in rows between bundles

dense regular connective tissue function and location

functions to provide strong attachment between structures; forms tendons, most ligaments, and aponeuroses

dense irregular connective tissue

collagen fibers with FEW fibroblasts

dense irregular connective tissue function and location

provides strength in many directions; located in fascia (tissue that surrounds muscles, organs), join capsules, dermis of skin

elastic connective tissue

consists of elastic fibers, fibroblasts between fibers

elastic connective tissue function and location

allows for stretching of lung tissue, walls of arteries, trachea, bronchial tubes, and vocal cords

what does elastic connective tissue consist of?

consists of elastic fibers, fibroblasts between fibers

cartilage

dense network of collagen or elastic fibers embedded in firm ground substance; collagen fibers strength and resilience

chondrocytes

mature cells for cartilage; located in spaces called lacunae

characteristics of cartilage

avascular; growth and repair occur slowly; no nerve supply

3 types of cartilage

hyaline, fibrocartilage, elastic

perichondrium

dense irregular CT that covers cartilage and does contain nerve supply

hyaline cartilage

contains fine collagen fibers and many chondrocytes; covered by perichondrium; most abundant type of cartilage

hyaline cartilage function and location

provides smooth surfaces for movement; flexibility and support; located at end of long bones, nose, larynx, bronchi

fibrocartilage

thick bundles of collagen with scattered chondrocytes; no perichondrium

fibrocartilage function and location

support, fusion, shock absorber; located in intervertebral discs, menisci of knee, pubic symphysis

elastic cartilage

threadlike elastic fibers with chondrocytes; covered in a perichondrium

elastic cartilage function and location

maintains shape and permits flexibility; located at top of larynx, external ear, and auditory tubes