histology Flashcards
what does the plasmalemma do ?
separates the cytosol from the outer environments
describe the plasmalemma
bimolecular layer of amphiphatic molecules with hydrophilic heads and hydrophobic fatty acid chains.
for the plasmalemma what is on the outer and inner surfaces ?
hydrophilic head
what does amphiphatic mean ?
contains both hydrophilic and hydrophobic parts
what does the plasmalemma contain (6) ?
integral proteins
transporter proteins
channel proteins
receptors
enzymes
cell attachment proteins
what permeability is the plasmalemma?
selectively permeable
what does the plamalemma allow through (3) ?
water
oxygen
small hydrophobic molecules
what are organelles ?
small intracellular ‘organs’ with specific function and structural organisation
what are examples of organelles (6) ?
mitochondria
RER
SER
Golgi apparatus
lysosomes
nucleus
what does the cytoskeleton provide ?
structural integrity to the cell
what is the cytoskeleton composed of (3) ?
actin protein
intermediate filaments
microtubules
how many main intermediate filaments are there ?
6 main proteins
what are microtubules composed of ?
2 microtubule proteins
why are microfilaments very dynamic ?
actin molecules can assemble into filaments and then disassociate
why can intermediate filaments be used in pathology to identify tumour origins ?
as different cells express different intermediate proteins
describe microtubules including the 2 things it is composed of
hallow tube
composed of two altering alpha and beta subunits of tubulin
where do microtubules originate from ?
centromere
what is MAP ?
microtubule associated protein
a stabilising protein
what drags organelles and vesicles along microtubules and what way ?
kinesin - towards periphery
dynein - towards the centre (dot)
what is continuous with the cistern of the ER ?
the perinucleur cistern
what is meant by euchromatin ?
DNA that is more dispersed and is actively undergoing transcription
what is meant by heterochromatin ?
DNA that is highly condensed and not undergoing transcription
what plays a vital role in protein synthesis ?
RER
will the RER have more ribosomes if a cell is more metabolically active ?
yes
how does the RER appear different from the SER?
RER is studded with ribosomes
what is the role of the SER ?
continues the process of proteins produced in RER
vital role in synthesising proteins
give an example of a cell that has lots of SER
steroid hormone synthasing cell
how does the Golgi apparatus appear ?
series of flattened, membrane bound cisternae
what is the role of the Golgi cisternae apparatus ?
function in the modification and packaging of macromolecules
how does Golgi cisternae fulfil its role ?
adds sugars, cleaves proteins and sorts macromolecules into vesicles
what increases surface area in the mitochondria and what is it formed by ?
cristae - formed be inner membrane
where does mitochondrial DNA come from ?
yo mama
what prevents diffusion ?
occluding junctions
how do cells connect with each other ?
intercellular junctions
what provides mechanical stability in skin ?
desmosomes
what junction is important in cardiac muscle and why ?
communicating junction - important for spread of electrical excitation
what allows selective diffusion of molecules between adjacent cell ?
communicating junction
what are the types of epithelium (7) ?
simple squamous
simple cuboidal
simple columnar
stratified squamous
stratified cuboidal
pseudostrtified columnar
transitional
what are the types of connective tissue (give examples ) ?
soft - tendons, ligaments, dermis of skin
hard - cartilage and bone
what is included in extracellular matrix ?
fibres
tissue fluis
adipose cell
osteocytes
chondrocytes
what are fibroblasts ?
active cells that produce and maintain cellular matrix.
what can soft tissue be divided into ?
loose
dense regular
dense irregular
what are spindle shaped cells with cigar shaped nucleus ?
smooth muscle
what muscle is voluntary and responsible for conscious control ?
smooth muscle
what muscle has more striations ?
skeletal muscle
what does nervous tissue consist of and what is the ratio between them ?
neurones and glia (their supporting cells)
1:10 glia outnumber neurons
what do astrocytes do ?
support ion transport
induce blood brain barrier
what do oligodendrocytes do ?
produce myelin in the brain and spinal cord
what do microglia do ?
provide immune survellence
what do Schwann cells do ?
produce myelin and support axons in the PNS
what are the three layer of blood vessels ?
tunia intima (inner layer)
tunica media (middle layer)
tunica adventitia (outer layer)
what is the tunica intima consist ?
simple squamous epithelium
supported by basal lamina and thin layer of connective tissue
what is the tunica media made of ?
mostly smooth muscle
