Chapter 2- Tissues Flashcards
Connective Tissue Characteristics
Variations in blood supply
- some are well vascularized
- some are avascular (poor blood supply)
- nonliving cells that surround living cells
Connective tissue
Found everywhere in the body
Includes the most abundant and widespread tissues
Functions - binds body tissues together, supports the body, provides protection
Extracellular Matrix
2 main elements
Ground substance: mostly water along with adhesion proteins and polysaccharide molecules
-fibers
–produced by the cells
–3 types
—collagen (white), elastic (yellow), reticular
Connective tissue types
Bone, hyaline cartilage, elastic cartilage, fibrocartilage, dense connective tissue, loose connective tissue (adipose, areolar, reticular)
Bone
Osseous tissue Composed of - bone cells in lacunae (cavities) - hard matrix of calcium salts - large numbers of calcium fibers Protect and support the body
Hyaline cartilage
Most common Composed of - abundant collagen fibers -rubbery matrix Locations -larynx -entire fetal skeleton before birth
Fibrocartilage
Highly compressible
Location
-cushion like discs between vertebrae
Elastic Cartilage
Provides elasticity
Location
-supports the external ear
Dense connective tissue
Dense fibrous tissue Main matrix element is collagen fibers Fibroblasts are cells that make fibers Locations Tendons:attach skeletal muscle to bone Ligaments: attach bone to bone at joints Dermis: lower layers of skin
Loose Connective Tissue types
Areolar, adipose, reticular connective tissue, blood
Areolar Tissue
most widely spread soft, pliable, like cobwebs packing tissue contains all fiber types can soak up excess fluid (causes edema)
Adipose Tissue
Matrix is an areolar tissue in which fat globules predominate many cells contain large lipid deposits funtions -insluates -protects organs -site of fuel storage
Reticular Connective Tissue
Delicate network of interwoven fibers locations -forms stroma (Internal supporting network) of lymphoid organs -- lymph nodes --spleen --bone marrow
Blood (vascular tissue)
Blood cells surrounded by fluid matrix called blood plasma
fibers are visible during clotting
functions as the transport vehicle for transport
Muscle Tissue Types
skeletal, cardiac, smooth
produce movement
Muscle Tissue Types
Skeletal, cardiac, smooth, nervous
Skeletal Muscle
voluntary control contracts to pull on bones or skin produces gross body movements or facial expressions characteristics -striated -multinucleate -long, cylindrical cells
Cardiac Muscle
involuntary control found only in heart pump blood characteristics -striated -one nucleus per cell -cells are attached to other cardiac muscle cells at intercalated disks
Smooth Muscle
involuntary found in walls of hallow organs such as stomach, uterus, & blood vessels characteristics -no striations -one nucleus per cell -spindle shaped cells
Nervous Tissue
composed of neurons and nerve support cells
send impulses to other areas of the body
-irritability
-conductivity
support cells called neuroglia insulate, protect, and support neurons
Tissue Repair (Wound Healing)
Regeneration
Fibrosis
Regeneration
replacement of destroyed tissue by the same kind of cells
Fibrosis
repair by dense (fibrous) connective tissue
scar tissue
Whether regeneration or fibrosis occurs depends on
types of tissue damaged
severity of the injury
Events in Tissue Repair
Inflammation
Granulation Tissue Forms
Regeneration of surface epithelium
Inflammation
Capillaries become very permeable
clotting proteins migrate to the area from the blood stream
clot walls off the injury
Granulation Tissue Forms
growth of new capillaries
rebuild collagen fibers
Regeneration of surface epithelium
scab detaches
Tissues that Regenerate Easily
Epithelial tissue (skin and mucous membranes) Fibrous connective tissues and bones
Tissues that regenerate Poorly
skeletal muscle
Tissues that are replaced largely with scar tissue
cardiac muscle
nervous tissue within the brain and spinal cord
Developmental Aspects of Tissue
Epithelial Tissue arises from all 3 primary germ layers
Muscle and Connective Tissue arise from the mesoderm
nervous tissue arises from the ectoderm
with old age, there is a decrease in mass and viability in most tissues
concepts of cell theory
basic structural and functional unit of living things
activity of an organism is based on collective activity of its cells
principle of complementarity states the biochemical activities of cells are dictated by the relative number of their specific sub-cellular structures
continuity of life has a cellular basis
chemical components of cells
carbon
hydrogen
oxygen
nitrogen
Cells and tissues
carry out all chemical activities needed to sustain life
cells are building blocks of all living things
tissues are groups of cells that are similar in structure and function
Body Tissues
4 primary types -epithelial tissue (epithelium) -connective tissue -muscle tissue -nervous tissue -epithelial tissue locations -body covering -body linings -glandular tissue functions -protection -absorption -filtration -secretion
Epithelium Characteristics
fit close together form sheets apical surface: free surface of the tissue lower surface: basement membrane avascular regenerate easily if well nourished
Classification of Epithelia
Number of cell layers -simple: one layer -stratified: multiple layers Shape of Cells -squamous (flattened) -cuboidal (cube-shaped) -columnar (column-like)
Simple Squamous
single layer forms membranes -lines body cavities -lines lungs and capillaries functions -diffusion -filtration -secretion of membranes
Simple Cuboidal
single layer locations -common in glands and their ducts -forms walls of kidney tubules -covers the ovaries functions -secretion -absorption simple epithelia
Simple Columnar
single layer mucus-producing goblet cells location -lines digestive tract functions -secretion -absorption
Pseudostratified Columnar
Single layer, but some cells are shorter than others
often looks like double layer, but all cells rest on the basement membrane
location
-respiratory tract
functions
-absorption
-secretion
Stratified squamous
cells at the apical surface are flattened function -protection where friction is common locations -lining of the skin, mouth, esophagus
Stratified Cuboidal
2 layer cuboidal cells
protection
Stratified Columnar
surface cells are columnar
cells underneath vary in size and shape
protection
Stratified Cuboidal and Columnar
RARE in human body
found mainly in ducts or large glands
Transitional Epithelium
composed of modified stratified squamous epithelium
shape of cells depends upon the amount of stretching
functions
-stretching and being able to return to normal shape
location
-lines organs of the urinary system
Glandular Epithelium
1 or more cells responsible for secreting a particular product
secretions contain protein molecules in aqueous (water-based) fluid
2 major gland types
-endocrine
-exocrine
Endocrine gland
DUCTLESS since secretions diffuse into blood vessels
all secretions are hormones
Exocrine gland
secretions empty through DUCTS to the epithelial surface
include sweat and oil glands
