BIOL125 Lecture Notes - Lecture 6: Synovial Fluid, Ground Substance, Fibrocartilage
8 Jun 2018
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Tissues
• 2.7. What is a tissue?
o Groups of cells work co-operatively together to form tissues
o Tissues perform specific functions as a group
o Cell structure and function is related to tissue function
o 2.7.1. The four basic tissue types in the body
• Muscle
• Neural (nervous)
• Epithelial
• Connective
o 2.7.2.Their locations and functions
• One tissue often works with the assistance of other tissues
▪ Blood (connective tissue) transports nutrients, wastes and gases to and
from all other cells and tissues
▪ Fibrous connective tissues surround skeletal muscles to protect them
• Muscle tissue
▪ Primary function is to contract or shorten
▪ Controlled contraction allows movement in the body
▪ Three types
• Cardiac
• Striated but not as obvious as in skeletal tissue
• Involuntary muscle found in the heart
• Typically has one centrally located nucleus per cell
• Cells have branched ends
• Intercalated discs are on the ends of the cardiac muscle
cells
• Tightly hold cardiac muscles together
• Contains lots of pores which allows for depolarisation
• Allow communication between cells for the
conduction of impulses during the cardiac cycle
• Skeletal
• Only found in a skeletal muscles
• Striated and the fusion of cells produces longer, mature
cells that are multinucleate
• Nuclei found on the edge of the cells
• voluntary
• Typically found near joints
• Cells are long cylinders
• Contractile proteins allow for muscles to shorten
• Smooth
• Not striated and involuntary
• Cells are slender and have one nucleus located in the centre
of the cell
• Found in the middle layer of all of the hollow organs in the
body apart from the heart
• Little tapered cells
• Contract as a whole around the hollow tube
• Twisting type of contraction compared to cardiac and
skeletal where its linear
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• Neural/nervous tissue
▪ Primary function is to conduct electrical impulses throughout the body
▪ Information contained in pattern and frequency of impulses
▪ Neurons transmit impulses - neuroglia support neutrons
▪ Dendrites - point of contact between sensory receptors or other
neurons
▪ Cell body - nucleus is
▪ Axon - sends the message to the axon terminals to forward the message
through neurotransmitters to the next cell
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find more resources at oneclass.com
• Epithelial tissue
▪ Lines and covers internal and external body surfaces
• Cells tightly interconnected
• Avascular - no blood vessels so it sits on basement membrane of
connective tissue
▪ Functions
• Physical protection from abrasion and chemicals
• Protection from dehydration
• Allows sensation
• Forms gland which produce secretions
• Connective tissue
▪ All connective tissues apart from blood and lymph (no fibres) have the
same basic construction
• Background matrix
• Cells
• Protein fibres
▪ e.g. areolar (loos) CT has gel matrix, collagen and elastin fibres,
fibroblasts and macrophages
▪ Classified according to physical properties
• CT proper - loose CT, dense regular CT, dense irregular CT, elastic CT,
adipose and reticular tissues
• Fluid CT - blood and lymph
• Supporting CT - bone and cartilage
▪ Functions
• Connects epithelium to rest of body
• Provides structure
• Store energy reserves
• Transport materials throughout the body (blood and lymph fluids)
• 2.8. The different types of epithelial tissue
o Squamous epithelia
• Thin, flat and irregular in shape
• Simple - most delicate type
▪ Located in protected regions where absorption or diffusion takes place,
or where a slick, slippery surface reduces friction
▪ Single nuclei in the centre
▪ e.g. surface of alveoli in the lungs
• Stratified
▪ Generally located where mechanical stresses are severe
▪ Cells form a series of layers
▪ e.g. surface of the skin and lining of the mouth
o Cuboidal epithelia
• Resemble hexagonal boxes from their apical surfaces
• The spherical nuclei are near the centre of each cell, and the distance
between adjacent nuclei is roughly equal to the height of the epithelium
• Simple
▪ Provides limited protection and occurs where secretion or absorption
takes place
▪ e.g. kidney tubules
• Stratified
▪ Relatively rare
▪ e.g. ducts of sweat glands and in larger ducts of the mammary glands
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