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simple squamous epithelium
description- single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm, simplest of epithelia
simple squamous epithelium
function- allows passage of materials by diffusion and filtration in sites where protection is not important, secretes lubricating substances in serosae (tissue lining of a body cavity or outer lining of an organ)
simple squamous epithelium
location- kidney glomeruli, air sacs of lungs, lining of heart, blood vessels and lymphatic vessels, lining of ventral body cavity
two types of simple squamous epithelium
endothelium, mesothelium
endothelium
provides a slick, friction-reducing lining in hollow organs that transmit bodily fluids (lymph, blood)
mesothelium
is the epithelium found in the serous membranes lining the ventral body cavity and covering its organs
simple cuboidal epithelium
description- single layer of cube like cells with large spherical central nuclei
simple cuboidal epithelium
function- secretion and absorption
simple cuboidal epithelium
location- kidney tubules, ducts and secretory portions of small glands, ovary surface
simple columnar epithelium
description-single layer of tall cells with round to oval nuclei, some cells bear cilia, layer may contain mucus-secreting unicellular glands (goblet cells)
simple columnar epithelium
function- absorption, secretion of mucus, enzymes and other substances, ciliated type propels mucus (or reproductive cells) by ciliary action
simple columnar location
location- nonciliated type lines most of the digestive tract (stomach to anal canal) gallbladder and excretory ducts of some glands, ciliated variety lines small bronchi, uterine tubes and some regions of the uterus
stratified squamous epithelium
description- thick membrane composed of several layers, basal cells are squamous, in the keratinized type, the surface cells are full of keratin and dead, basal cells are active in mitosis and produce the cells of the more superficial layers
stratified squamous epithelium
function- protects underlying tissues in areas subjected to abrasion
stratified squamous epithelium
location- nonkeratinized type forms the moist linings of the esophagus, mouth, and vagina; keratinized variety forms the epidermis the skin, a dry membrane
psuedostratified ciliated columnar epithelium
description- single layer of cells of differing heights, some not reaching the free surface, nuclei seen at different levels, may contain mucus-secreting cells and bear cilia
psuedostratified ciliated columnar epithelium
function- secretion, particularly of mucus, propulsion of mucus by ciliary action
psuedostratified ciliated columnar epithelium
location- nonciliated type in male’s sperm-carrying glands, ciliated variety lines the trachea, most of upper respiratory tract
transitiional epithelium
description- resembles both stratified squamous and statified cuboidal, basal cells cuboidal or columnar, surface cells dome shaped or squamous-like, depending on degree of organ stretch
transitiional epithelium
funciton- stretches readily and permits distention of certain hollow organs (bladder)
transitional epithelium
location- lines the ureters, urinary bladder, and part of the urethra
mesenchyme
an embryonic tissue, gives rise to all connective tissues
what makes up the extracellular matrix?
protein fibers and ground substance
what makes up ground substance?
collagen fibers, elastic fibers, and reticular fibers
fibroblasts
stationary cells that secrete proteins that join other molecules in the matrix to form fibers
mast cells
detect foreign microorganisms and initiate immune responses against them
adipocytes
fat cells and contain vacuoles for the storage of lipids
loose connective tissue
has an open network of protein fibers in a thick, syrupy ground substance and is divided into three groups
dense connective tissue
is made up of two types of fibers: protein fibers assembled into thick bundles of collagen and elastic fibers with widely scattered cells
what are the two types of dense connective tissue?
dense regular and dense irregular
dense regular connective tissue
protein fibers in the matrix are arranged in parallel bands
dense irregular connective tissues
fibers are interwoven, fibers that run in many directions and is found where tension is exerted from many different directions such as in the capsules of some organs and joints, the dermis of the skin and the submucosa of the digestive tract
two types of fluid connective tissue
blood and lymph
two types of supporting connective tissue
bone and cartilage
perichondrium
membrane that surrounds all supporting connective tissue and produces chondroblasts
lacunae
small spaces in the matrix where chondroblasts become trapped
chondrocytes
chondroblasts become chondrocytes after becoming trapped in the lacunae
three types of cartilage
hyaline, elastic, and fibrocartilage
areolar tissue
description- gel-like matrix with all three fiber types, cells: fibroblasts, macrophages, mast cells, and some white blood cells
areolar tissue
function- wraps and cushions organs, its macrophages phagocytize bacteria, plays important role in inflamation, holds and conveys tissue fluid
areolar tissue
widely distributed under the skin
adipose tissue
description-matrix as in areolar, but very sparse, closely packed adiposcytes (fat cells) have nucleus pushed to the side by large fat droplet
areolar tissue
function- provides reserve food fuel, insulates against heat loss, supports and protects organs
areolar tissue
location- under skin subcutaneous tissue around kidneys and eyeballs, within abdomen, in breasts
reticular tissue
description- network of reticular fibers in a typical loose ground substance, reticular cells lue on the network
areolar tissue
function- fibers form a soft internal skeleton (stroma) that supports other cell types including white blood cells, mast cells, and macrophages
reticular tissue
location- lymphoid organs (lymph nodes, bone marrow, and spleen)
dense regular connective tissue
description- primary parallel collagen fibers, a few elastic fibers, major cell type of the fibroblast
dense regular connective tissue
function- attaches muscles to bones or to muscles, attaches bone to bone, withstands great tensile stress when pulling force is applied in one direction
dense regular connective tissue
location- tendons, most ligaments, aponeuroses
dense regular elastic tissue
description- dense regular elastic tissue containing a high proportion of elastic fibers
dense regular connective tissue
allows recoil of tissue following stretching, maintains pulsatile flow of blood through arteries, aids passive recoil of lungs following respiration
dense regular connective tissue
location- walls of large arteries, within certain ligaments associated with the vertebral column, within the walls of the bronchial tubes
blood
description- red and white blood cells in a fluid matrix
blood
function- transport of respiratory gases, nutrients, wastes, and other substances
hyaline cartilage
description- amorphous but firm matrix, collagen fibers form an imperceptible network, chondroblasts produce the matrix and when mature
hyaline cartilage
function- supports and reinforces, has resilient cushioning properties, resists compressive stress
hyaline cartilage
location- forms most of the embryonic skeleton, covers the ends of long bones in joint cavities, forms costal cartilages of the ribs, cartilages of the nose, trachea, and larynx
elastic cartilage
description- similar to hyaline cartilage, but more elastic fibers in matrix
elastic cartilage
maintains the shape of a structure while allowing great flexibility
elastic cartilage
location- supports the external ear (pinna), epiglottis
fibrocartilage
description- matrix similar to but less firm than that in hyaline cartilage, thick collagen fibers predominate
fibrocartilage
function- tensile strength with the ability to absorb compressive shock
fibrocartilage
location- intervertebral discs, pubis symphysis, discs of knee joint
skeletal muscle
description- long cylindrical, multinucleate cells, obvious striations
skeletal muscle
function- voluntary movement, locomotion, manipulation in the environment, facial expression
skeletal muscle
location- in skeletal muscles attached to bones or occasionally to skin
muscle fibers
long cells that make up skeletal muscle
myoblasts
embryonic cells that fuse into one large cell to form the muscle fiber
myofilaments
intercontractile proteins that create a distinct band pattern (actin and myosin)
cardiac muscle
description- branching, striated, generally uninucleate cells that interdigitate at specialized junctions (intercalated discs)
cardiac muscle
function- as it contracts, it propels blood into circulation, involuntary control
cardiac muscle
location- the walls of the heart
what makes up skeletal muscle?
connective tissue layers generated by fibroblasts and contain endomysium between individual cells; cardiocytes are connected to one another via intercalated discs, which coalesce at ends of the cells in dense desmosome rich patches
smooth muscle
description- spinde-shapped cells with central nuclei; no striations, cells arranged closely to form sheets
smooth muscle
function- propels substances or objects (food, urine, or a baby) along interal passageways; involuntary control
smooth muscle
location- mostly in the walls of hollow organs
how are smooth muscles contracted?
induced and influenced by intracellular communication through gap junctions, hormones, mechanical stress, and different neurotransmitter
nervous tissue
description- neurons are branching cells, cell processes that may be quite long extend from the nucleus-containing cell body; also contributing to nervous tissue are the non-irritable supporting cells
nervous tissue
function- transmit electrical signals from sensory receptors and to effectors (muscles and glands)
nervous tissue
location- brain, spinal cord, nerves
what cells make up the nervous system?
neurons and glial cells
what is nerve tissue also known as?
neural tissue
effectors
a tissue/organ/structure in the body that processes information from sensory organs and responds with motor instructions to muscles and glands
neurons
cells responsible for receiving, interpreting, and sending the signals of the nervous system
cell body or soma
the central nucleus of a neuron
dendrites
fine extensions radiating out from the soma/cell body; receive signals from other cells and send this information to the soma
“trigger zone” of neuron
region where axon fuses to soma, where signals from dendrites are integrated’ determines if an action potential will be initated or not
periosteum
membrane that surrounds bone supporting tissue, contains osteoblasts
osteoblasts
in the periosteum, cells for bone growth and repair; secrete organic components of the matrix, become trapped in the lacunae and mature into osteocytes
osteocytes
matured osteoblasts
osteon (haversian system)
repeating structural units made of rings of concentric lamellae surrounding a central (haversian) canal that contains blood vessels and nerves
haversian canal
central canal of osteons
canaliculi
small channels in the lamellae that provide passageways through the solid matrix for diffusion of nutrients and wastes
osteoclast
bone destroying cells
in what two ways does bone ossify?
intramembranous bone (cranial bones and clavicle) develop from fibrous membranes and endochondral bone
perforating canal (Volkman’s canal)
runs perpendicular to the osteon; nerves, blood vessels, lymphatic vessels all pierce the periosteum and enter the bone in this canal; interconnects with the central canal
what comprises the integumentary system?
skin, sweat glands, oil glands, hair, nails
what is the purpose of the integumentary system?
give the body a protective barrier (flexible and resistant to everyday abrasions and water loss resistant), regulate body temp, house sensory receptors, ensure water homeostasis, protect body, manufacture vitamin D
what are the two main tissue layers of the skin?
epidermis (superficial and avascular), dermis (deep and vascularized)
