anatomy exam

histology

branch of anatomy that deals with the microscopic study of tissues in plants and animals which intertwines many other disciplines like pathology, biology and physiology

microscopy

magnification up to 500x, suitable only id the tissue is transparent and if its not slice it thinner, use a stronger light source and use filters and slides are 2d either transversal or longitudinal

staining components

basic cell components like cytoplasm, proteins, filaments in muscle cells, intracellular membranes and collagen/elastin are stained with acidic dyes
acidic cell components like DNA, RNA/ribosomes and carbohydrates in cartilage are stained with basic dyes

giemsa stain

basic dye is methylene and acidic dye is eosin and azure, stains the nuclei dark purpose, cytoplasm pale blue and erythrocytes pink which is excellent for identifying blood cells

haematoxylin and eosin stain

basic dye is haematoxylin and acidic dye is eosin, stains the nuclei purple/blue and the cytoplasm and extracellular matrix pink which is excellent for identifying inflammation, pathology and structures

tissues

groups of specialised cells with a common function

muscle tissues

used for movement

muscle tissue - functions

enable contraction by shortening in response to a stimulation

muscle tissue - features

highly cellular: composed of long cylindrical or spindle shaped cells
highly vascular: requires large blood supply for high metabolic demands

muscle tissue - classifications

smooth, cardiac and skeletal tissue

muscle tissue - skeletal

striations: alternating light and dark bands
multinucleated: multiple nuclei per fiber for efficient protein synthesis
peripheral nuclei: located just beneath the cell membrane
volutnary control: consciously controlled by the nervous system

muscle tissue - cardiac

striations: alternating light and dark bands
uni/bi nucleated: 1 to 2 central nuclei per fiber
intercalated disc: specialised connections for synchronised contraction
branched cells: creates a network for coordinated contraction
involuntary control: contracts automatically to pump blood

muscle tissue - smooth

no striations
uninucleated: 1 central nuclei per fiber
spindle shaped cells: tapered at both ends
two layers: inner circular wraps around the lumen and outer longitudinal runs along the length of the organ
involuntary control: found in walls of hollow organs

connective tissue

used for support

connective tissue - functions

support, protection, insulation, transport and energy storage

connective tissue - features

highly variable: vascular or avascular
ground substances: gel like matrix filling the space between cells composed of water glycoproteins and proteoglycans allowing for hydration, nutrients diffusion and tissue support
fibers: embedded in ground substances with collagen fibers providing strength, reticular fibers forming supportive mesh and elastic fibers allowing for stretch and recoil
cells: contains fibroblasts which produce ground substances and fibers

connective tissue - classifications

connective tissue: loose and dense (regular and irregular)
fluid connective tissue: blood and lymph
supportive connective tissue: bone (compact and spongy) and cartilage (hyaline, elastic and fibro)

connective tissue - loose

loosely arranged fibers, highly vascularised, flexible, binds and supports other tissues providing protection, contains fibroblasts and immune cells and sub types include areolar, adipose and reticular

connective tissue - dense regular

collagen fibers align and run parallel and highly unidirectional forming resistance to stress like tendons and ligaments

connective tissue - dense irregular

collagen fibers are randomly interwoven and resistant to distension in all directions like dermis of the skin and organs

connective tissue - blood

lacks structural fibers, transportation, regulation and protection, extracellular matrix is composed of water, proteins, hormones, nutrients and waste and contains thrombocytes for blood clotting, leukocytes for immune defence and erythrocytes for oxygen and carbo dioxide transport

connective tissue - bone

support, protection, muscle attachment, blood cell production and mineral storage and contains osteoblasts which build the matrix, osteoclasts which breakdown the matrix, osteocytes which maintain mature bone and osteoprogenitor/stem cells which become osteoblasts

connective tissue - compact bone

cortical bone, dense outer layer and structural units are osteons

connective tissue - spongy bone

cancellous bone, porous inner network/trabeculae and contains red bone marrow

connective tissue - cartilage

composed of chondrocytes in a gel like matrix, high avascular and all surrounded by perichondrium except fibro which supplies nutrients

connective tissue - hyaline

fine collagen fibers providing flexible structures and reduces friction like nose and trachea

connective tissue - elastic

fine collagen and elastin fibers maintaining shape while allowing flexibility like epiglottis and external ear

connective tissue - fibro

thick bundles of collagen fibers which are resistant to compression and tension like intervertebral discs and knee menisci

epithelial tissue

used for protection and coverage

epithelial tissue - functions

highly cellular and avascular
secretion, barrier, protection, absorption, sensation and transcellular transport
innervated
cell to cell contact
polarity: apical surface faces lumen and basal surface attaches to the basement membrane

epithelial tissue - features

basal lamina: sits on a bed of loose connective tissue and anchors epithelium to it forming a scaffold for support and contains glycoproteins and collagen
keratin: fibrous structural protein with the keratinised dead squamous cell layer being the epidermis of the skin
cilia: transports mucus and debris along surfaces
microvilli: increase surface area for absorption

epithelial tissue - classification

simple squamous, simple cuboidal, simple columnar, stratified squamous (keratinised and non-keratinised) and pseudostratified cuboidal

epithelial tissue - simple squamous

single layer of thin flat cells allowing rapid absorption, facilities diffusion and thin membranes like alveoli in lungs and bowmans capsule in kidneys

epithelial tissue - simple cuboidal

single layer of cubed cells allowing absorption and secretion, may be ciliated and nucleus is spherical and central like kidneys and pancreas

epithelial tissue - simple columnar

single layer of tall column cells allowing absorption and secretion, may be ciliated and nucleus is oval near the basal lamina like respiratory and digestive tract

epithelial tissue - stratified squamous keratinised

multiple stacked layers of cells composed of a superficial layer of dead squamous cells with no nuclei and filled with keratin which helps protect from stress, evaporation and damage

epithelial tissue - stratified squamous non-keratinised

multiple stacked layers of cells which has nuclei and white spaces like cornea and vaginal canal

epithelial tissue - pseudostratified cuboidal

appears multilayered but all cells sit on the basement membrane with nuclei at varying heights giving the illusion of multiple layers and may be ciliated eg. trachea and male reproductive tract

neural tissue

used for communication

neural tissue - functions

specialised for electrochemical communication

neural tissue - features

highly cellular
neurons: send and receive signals with cell bodies, axons and dendrites
glia: small supporting cells maintaining homeostasis, forms myelin and nourishes and defends neurons
nuclei: clusters of neuron cell bodies in the CNS
ganglia: clusters of neuron cell bodies in the PNS
lamina: layers of neurons organised in sheets in the CNS