Complex multicellular organisms, groups of cells have differentiated in special ways to form tissues, organs and systems.
Tissue
Groups of similar cells w/ similar function-epithelial (covering), connective (support/transport), muscle, nervous (control)
Tissues are generated by which embryonic tissues?
Ectoderm, Mesoderm, Endoderm
Muscle types
smooth - involuntary, cardiac-uni/binucleate, branched, striated, involuntary, only in heartskeletal-multinucleate, unbranched, striated
How are muscles different?
distribution in the body, striated, number of nuclei in the cell, whether cells are branched or unbranched, voluntary or involuntary
Skeletal
striated, voluntary. multinucleate, unbranched,
cardiac
striated, involuntary, only in heart. uni/binucleate, branched,
Smooth Muscle
Viceral, non striated and involuntary . Can also occurs at body periphery in eyes and skin. Cells are uninucleate, unbranched, and smooth (not striated). Involuntary
Connective Tissue (general)
Provides body with structural building blocks, defense/immune cells, spaced apart, embedded in a matrix
Nerve Tissue (General)
Neurons transmit signals. supporting cells support neuronal function in a few ways: physical, chemical, nutritional support, some supporting cells increase the speed of nerve signal transmission, some act as immune cells defending the brain and spine ag.
Functions of Connective Tissue
Bind and support, protect (defensive cells of the immune system), insulation, transport and store substances
Characteristics of Connective tissue
all derived from mesenchime, varying degrees of vascularity, extracellular matrix (there may be a lot of space bet cells)
Connective tissue composition
Ground Substance, Fibers, Cells. Cells=living portion. GS and fibers occur between cells = extracellular matrix
Ground substance
Unstructured material that fills the space bet. the cells and contains the fibers. Contains GAGs
GAGs
Contain many acid sugar molecules, get entangled in each other and trap water, varying fluidity, fx like sponges. Examples: Chondroitan sulfate, Keratan sulfate and HA
Fibers
Provide support. Collagen (strong and provide consistency and support for the tissues - they bind cells together) and Elastic (resiliant and stretchable found where additional elasticity is required i.e. in skin, blood vessels and lungs)
Gel like structure with 3 fiber types, widely distributed under epithelia, packages organs/capilaries, GS is semi fluid/gelatinous (HA), fluid resovior
Apipose Connective Tissue
Gel like matrix w/ 3 fiber types. Many closely packed adipocytes (fat cells). Focuses on storing energy for future use
Adipocytes
fat cells
Dense Connective tissue
contains closely packed bundles of collagen, have few cells other than fibroblasts, poorly vascularized
Dense Regular Connective tissue
collagen fibers are arranged in dense, parallel ways, few elastin fibers are present, i.e. tendons and ligaments
Dense Irregular Connective tissue
major fiber is collagen, fibers randomly arranged, some elastin is present (resiliency), i.e. dermis of the skin and fiberous capules of organs and joints
Cartilage (General)
Avascular, GS = collagen fibers and sometimes elastin. Developed by chondroblasts > maintained by chondrocytes. GS contains proteoglycans (large protein carb molecules and GAGs
Glycosaminoglycans = GAGs.
protiens containing sugar molecules - charged polysaccharides. stick out from the protein core like bristles on bottlebrush. They intertwine, - charges attract and hold water, forming a fluid matrix w/ varied consistency. Sponge. ie. HA
Cartilage Qualities
contains up to 80% water (due to GAGs i.e. HA and chondroitin), enables cartilage to rebound, most structures are covered by perichondrium & matrix is heavily invested with collagen fibers for strength and sometimes elastic fibers of resiliency
Perichondrium
a dense irrecular connective tissue capsule, that surrounds most cartilage structures (i.e. like the bone is surrounded by a periosteum). Nutrients diffuse via perichondrium
Fibroblasts
the immature form of a cell that is responsible for secreting the particular extracellular matrix > connective tissue proper
Chrondoblasts
the immature form of a cell that is responsible for secreting the particular extracellular matrix > cartilage
Osteoblasts
the immature form of a cell that is responsible for secreting the particular extracellular matrix > bone
Hemocytoblasts
the immature form of a cell that is responsible for secreting the particular extracellular matrix > blood
Beef Production
