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60 terms

Histology - Lab Practical

Info on all histology slides for Tony Huntley's bio lab practical II
the study of tissues
Four Major Types of Vertebrate Tissue
epithelial, connective, muscle, and nervous
Organization of an Organism
atoms-->molecules --> cells--> tissue--> organ --> organ system--> organism
Epithelial Tissue
- form sheet like layer of cells with very close cell to cell contact
- fxns: protection, absorption, and excretion of materials for an organism
Epithelial Classification
based on:
1.) the number of layers
2.) the shape of the cells on the free surface
Simple Epithelia
- surface lining consisteing of a single layer of cells
- found at places where selective diffusion, absorption, or secretion occurs
- ranges from squamous, cuboidal, and columnar
- a dense layer of extracellular material that acts as a "glue" to hold cells together
Simple Squamous Epithelium
single layer of flattened cells, containing a flattened nucleus
- line lumens of the of blood vascular system (aka endothelim), the renal corpuscles, and lumenal surfaces of the pleural and peritoneal membranes, and mesothelium
-fxn: diffusion of materials
- cells are hexogonal in shape
Simple Cuboidal
- single layer of cube-shaped cells with centrally located nucleus
- found in exocrine glands (salivary & mucous), ducts, and tubules (ex: kidney tubules) & in ovaries and pancreatic duct
- fxn: secretion and some diffusion
Simple Columnar
- height is greater that its width
- touch the basement membrane and the nuclei are aligned in the center, towards the bottom of the cell
- some are ciliated
-fxn: secretion and some absorption
- location for non-ciliated: lines stomach & intestines, salivary glands, and gall bladder
- location for ciliated: uterine tubes, fallopian tubes, upper respiratory tract
Goblet Cells
- associated with columnar cells
- secrete mucus
Psuedostratified columnar epithelium
- the cells begin at a basement membrane but some do not reach the free surface
- nuclei appear to be in 2 rows
-locations: eustachian tubes, upper respiratory tract, vas deferens
Stratified squamous
-composed of cell with many layers
- cells are flattened at the free surface, but look cuboidal or columnar at the basement layer
-fxn: protection, coverings in areas of lots of abuse
- locations: skin & lining wet surfaces: mouth, esophagus, vagina
2 types of Connective Tissue
Loose & Dense
Connective Tissue
- composed of cells and extracellular fibers imbedded in a ground substance (matrix)
- has 3 types of fibers: elastic fibers, collagen fibers, and reticular fibers
Ground Substance (matrix)
- can be jelly-like, liquid, or solid non-living cement of glue secreted by the cells
Elastic fibers
- composed of elastin (protein) with a stretchy and flexible characteristic
- form thin wavy lines that can be stained purple, red or brown
Collagen fibers
- composed of collagen protein and found only animals
- thick and resist stretching
- when stained, appear as thick wavy lines that are pink/ red
Reticular fibers
- inelastic
- branching forming a network
Blast cells
- responsible for the production of a particular substance
ex: fibroblasts produce fibers
Clast cells
- responsible for re-absorbing substance
- fibroclasts- breakdown fibers
"Cyte" cells
- resting or mature cells that are not producing or reabsorbing substances
ex: fibrocytes- mature fiber cells
Types of Loose Connective Tissue
- areolar connective and adipose tissues
Areolar Connective Tissue
-least specialized connective tissue in adult organisms
- "packing material" of the body
-location: anchors blood vessels, nerves, and body organs
Adipose Tissue
- have large vacuoles for lipid storage
- have fibroblasts, elastic and collagenous fibers
- the fibers are laid down randomly in all directions
- location: nearly everywhere, especially around heart, kidneys, & subcutaneous connective tissue
Types of Dense Connective Tissue
- White (dense) fibrous connective, bone, hyaline cartilage, elastic cartilage, & vascular tissue
White (Dense) fibrous connective Tissue
- composed of collagenous fibers in a wavy, parallel lines
- locations: tendons, cornea, most ligaments & periosteum
- cell type in the this tissue ( fibroblasts)
-composed of collagen and mineralized calcium & phosphate salts
- composed of Haversian systems
- fxn: mechanical support, locomotion, protection, and mineral salt resorvoir
Haversian (osten) canals
-located in Haverian systems
- has an arteriole, venule, and nerve supply
- bone-forming cells that wall themselves within lacunae
- tiny branching channels that interconnect cells in the lacunae
Volkmann's canal
- allows the passage of nourishment from osteon canal to the other
- the arrangment of osteoblasts/osteoclasts in concentric layers
Hyaline Cartilage
- aka gristle
- most common type of cartilage
- contains both elastic and collagen fibers
-locations: articular surface of the bones, end of nose, fetal skeleton, trachea, costal cartilage
- found within the lacunae of hyaline cartilage
- produce ground substance, cartilage
mature cells in the outer portion of the cartilage
Elastic cartilage
- contains numerous elastic fibers
- lacunae are more densely clustered containing chondrocytes
- locations: external ear, auditory tube epiglottis
Vascular Tissue
RBC's, WBC's
- derived from loose connective tissue with various cells called corpuscles which are suspended in a fluid matrix called the plasma
-fxn: transports nutrients, O2 & CO2, hormones, and waste products
- biconcave, enucleated
Birds and reptile have nucleated RBC's
- contain hemoglobin for O2 and CO2 transport
- part of the immune response
- classification is based on granulation
- do not have granules in the cytoplasm
ex: lymphocytes and monocytes
- 20-25% of WBC's
- small with large dark blue nucleus with thin crescent shaped rim of light blue cytoplasm
- responsible for production of T and B cells
3-8% of WBC's
- large, U-shaped nucleus
- larger than lymphocytes
- phagocytic- eat foreign bodies
- called macrophages when they are actively phagocytizing foreign bodies
- have granules that stain in the cytoplasm
-65-75% of WBC's
- nucleus with 3-5 interconnected lobes
-granules stain light pink-purple
- phagocytic in connective tissue
2-5% of WBC's
- bilobed nucleus
- granules stain red-orange
- increase in #'s during parasitic infections & allergic rxns
1% of WBC's
- S-shaped nucleus obscured by dark purple granules
- no cytoplasm can be seen
- involved in non-specific inflammatory response--> release histamine
3 Muscle Types
Skeletal, Smooth, & Cardiac
Skeletal Muscle
-long cells with striations
- multiple peripheral nuclei
-thin ones are capable of rapid activity
- thick ones- contract more slowly, with greater force
- voluntary muscles of the body
Smooth Muscle
- non-striated
- spindle shaped
-muscles are involuntary
- found in organs of the body and vessels
Cardiac Muscle
- striated and branched with a single central nucleus
- have intercalated disks between the cells
- found only in the heart
Nervous Tissue
- composed of neurons
Anatomy of a Neuron
- cell body called a soma with a nucleus
- extensions called dendrites
- longer axon
- fxn: receive electrical impulses from various stimuli and transmit the info to the soma
carries impulses away from the soma to a particular organ
- may or may not be myelinated
Myelinated axons
- enclosed by concentric rings of lipid layer that insulates the axon
Schwann cells
- produce the myelin sheath (made of lipids)
nodes of Ranvier
gaps in the myelin sheath where the axon is exposed
- increases the rate of conduction
Axon termini
- located at the end of the axon
- innervate various structures
terminal bouton
- at the end of the axon termini
- the foot
- small gap between the terminal bouton and the innervated structure
- this is where neurotransmitters are released