Principles Histology Flashcards
Features of eukaryotes
nucleus, membrane bound organelles, cytoplasm + cytoskeleton, inclusions
features of plasmalemma
semi rigid, amphipathic phospholipid bilayer, anchored + laterally moving proteins, cholesterol between tails of lipids, semi permeable
Permeable to?
small uncharged molecules e.g. O2, H20
define exocytosis + endocytosis
Exo = excretion of materials Endo = intake of materials
Role of cytoskeleton
provide structure and support + allow movement
3 filaments involved in cytoskeleton
micro filaments, intermediate filaments, microtubules
features of microfilaments
actin filaments, globular, constantly breaking up + reassembling
features of Intermediate Filaments
more permanent, mechanical strength, specific to cell type
features of microtubules
hollow rods, made of alpha + beta tublin, radiate from centrosome, polar + act as motorway
movement along microtubules + carrier compounds involved
Dynein = moving towards cell centre kinesin = moving away from cell centre
Nucleus membrane
bi layered membrane (inner + outer) with perinucleur cistern between
Feature of perinuclear cistern
continuation of rough ER (proteins are trapped after being constructed)
transcription of m,r+t RNA
m + t RNA transcribed in nucleus, rRNA transcribed in nucleolus
2 forms DNA can be found in + definition
heterochromatin = densely packed Eurochromatin = loosely packed (undergoing transcription)
Structure of ribosome
1 large + 1 small sub unit
Rough Endoplasmic reticulum
Production of proteins, inner channel is continuation of perinuclear cisterna - captures translated proteins
Smooth Endoplasmic reticulum
production of lipids+ fats
Golgi Apparatus
modification of proteins e.g. cleavage + addition of sugar
features of mitochondria
produce ATP, bi membrane, inner membrane invaginates (cristae)
3 types of cell junctions
1) occluding junctions
2) anchoring junctions
3) communicating junctions
occluding junctions
links 2 cells together, creates a diffusion barrier, reduces extracellular space, zonula occlusion
2 types of anchoring junctions
zonula adherns + desmosome
desmosome + zonula adherns
both - transmembrane proteins bind to adjacent cell in extracellular space. desmosome bound to centrosome in cell, zonula adherns bound to cytoskeleton
2 main stains used
haematoxylin = bacic die binds to acids (blue) eosin = acidic die binds to bases (pink)
4 main tissue types
1) epithelium
2) connective tissue
3) Muscle
4) Nervous tissue
Uses of epithelium
Line surfaces + hollow organs + glands
Features of epithelium
strong junctions between cells, form sheets - small intercellular space, basal lamina keeps them attached, non vascular - nutrients diffuse in via basal lamina, polarized - basal and apical ends
3 types of epithelium
squamous - flat
cuboidal - cube
columnar - rectangular
3 arrangements of epithelium
simple - 1 cell thick layer
stratified - multiple layers
pseudostratified - appears as many but all attached to basal lamina
2 types of glands + specifications
endocrine - basal excretion, into blood stream
exocrine - apical excretion into duct
3 types of connective tissue
1) soft CT
2) hard CT
3) blood and lymph
features of CT
greater extracellular matrix, made up of cell type and extra cellular matrix
Extracellular matrix components
1) Fibres - collaged, elastic + reticular fibres
2) ground surface - amorphous space filler, made of glycoproteins (GAG’s + protein cores)
4 cell types in CT
fibroblast = extracellular matrix producer
Adipose cells = fat cells
Osteocytes = bone cells
Chondrocytes = cartilage cells
2 types of soft ct + difference
loose + dense.
Loose = loosely packed elastic fibres
Dense packed
2 forms of soft dense CT
regular - all aligned e.g. tendon
irregular - randomly aligned e.g. dermis
2 types of hard ct
cartilage + bone
3 types of cartilage + how they differ + features
1) Hyaline
2) elastic
3) fibrocartilage
- type depends on matrix + chondrocytes
- avascular, diffuses in through matrix
Bone features
osteocytes + matrix
haversian canal - cannals for neurones + blood vessels
2 layers of bone
cortical (outer)
cancellous (inner)
3 types of muscle
smooth, skeletal + cardiac
features of smooth muscle
non striated, visceral, elongated fibres (cigar shaped)
Skeletal features
striated, multinucleated (in sarcolemma)
Cardiac muscle
striated to lesser extent, tight junctions + communicating junctions, single nucleated
2 types of nervous tissue
neurone + glia
protective layers of CNS + PNS
CNS = meninges PNS = Epineurium
types of neurones
bipolar = 1 axon 1 dendrite, multipolar = many dendrites 1 axon, pseudounipolar = one long axon
3 types of glia in CNS
astrocytes, oligodendrocytes + microglia
role of each CNS glia
astrocytes = blood brain barrier + ion transport + mechanical support oligodendrocytes = myelin producing microglia = immune surveillance
glia in PNS + role
schwann cells - myelin producing
4 components of digestive tract
- mucosa
- sub mucosa
- muscularis propria
- serosa
3 layers of mucosa + function
epithelium - line the lumen/duct
lamina propria - loose connective tissue
muscularis mucosa - smooth muscle shape + size of lumen
sub mucosa
layer of connective tissue
muscularis propria
thick layer of muscle inner layer is circular, outer layer is linear
serosa/ adventitia
outer layer of connective tissue, suspends tract/ attaches to organ
basal lamina
tissue joining epithelium, very thin, non vascular - nutrients diffuse through to epithelium
amphipathic
both polar + non polar regions
structure phospholipids adopt
micells
