diversity of cells and their functions Flashcards
how would you see tissue under the light of a microscope?
would need to add dyes to actually see anything (stains)
what is H&E?
haematoxylin and eosin
H = dyes the nucleus purple and has an affinity for acidic molecules E = dyes basic cells ie cytoplasm pink/red and has an affinity for basic cells
what are the 4 basic tissue types?
epithelium
connective tissue
muscle
nervous tissue
what are characteristics of epithelia
> adhesions between these cells are strong ie have very little intercellular space
all have a basal lamina
they are non-vascular ie nutrients must travel from underlying tissue via diffusion through basal lamina
usually polarised
how would you classify covering epithelia?
> by cell shape ie squamous, cuboidal, columnar
by the no. of layers ie simple, stratified and pseudostratified
(less important):
>if they have a brush border ie microvilli
>cilia
>if they are keratinised ie layers of keratin proteins present on the tissue surface
>if they have goblet cells
what are the 2 forms of glandular epithelium?
endocrine and exocrine
what is the difference between endocrine glands and exocrine glands?
endocrine glands secrete their produce toward the basal end of the cell ie to try and get it into the blood stream - and so does not have a tube ‘ductless gland’, whereas
exocrine glands secrete their product toward the apical end of their cell ie into the lumen of an internal space and so has a tube - ‘ducted gland’
what are the three types of connective tissue?
> soft connective tissue ie tendons, dermis
**(can get dense regular soft connective tissue and dense irregular soft connective tissue and is to do with the way in which the fibres are organised)
hard connective tissue ie bone and cartilage
> > *blood and lymph
what does connective tissue consist of
> extracellular matrix (this is stuff like: fibres like collagen and ‘ground substance’)
cells
(“: fibroblasts, adipose cells, osteocytes and chondrocytes)
what are the characteristics of cartilage?
> semi-rigid tissue
is avascular ie receives nutrients from adjacent tissues via diffusion
there are three types: hyaline elastic and fibrocartilage
what are the characteristics of bone?
> an outer shell of cortical bone makes up the diaphysis
>cancellous/trabecular bone occupies the epiphyses - looks like a meshwork
what are the canals called in bone that allow for blood vessels and nerves?
haversian canals
what are the living cells called in bone?
osteocytes
what are the three main types of muscle tissue?
smooth
skeletal
cardiac
what are characteristic of smooth muscle?
> visceral
smooth ie has no visible striations
involuntary ie not under conscious control
what are characteristics of skeletal muscle?
`>constitutes the muscles of the body that respond to conscious control ie voluntary
>striated
**however not all striated muscles are skeletal ie the heart
what is significant about skeletal muscle fibre?
it is a giant multinucleate cylindrical cells - very long and wide
>each fibre has nuclei that are elongated and located at the periphery of the cell (the sarcolemma)
what are characteristics of cardiac muscle?
> has striations
forms major part of heart walls, chambers and origins of the great vessels
fibres are much shorter than striated muscle and branch (forming a complex network)
what is significant about cardiac muscle cells?
> have a single nucleus located near the centre of the fibre
there are intercalated discs, that pass across the fibres at irregular intervals ie end to end attachments between adjacent cells
what are characteristics of nervous tissue?
> consists of two main cell types: neurons and glia (support cells)
**neurons are far outnumbered by glia, like 10:1
nervous tissue is surrounded by a ‘coat’ of connective tissue
** ie for the CNS there is the meninges and for the PNS there is the epineurium
what are the three types (essentially) of neuron?
multipolar
bipolar
pseudo-unipolar
what are the three principal types of support cell (glia) in the CNS?
*and their purpose
> astrocytes: support, induce blood brain barrier
oligodendrocytes: produce myelin
microglia: immune surveillance
what is the principal glia of the PNS?
> Schwann cells: produce myelin and support axons
ECTMNT
think oesophagus slide
