histology Flashcards
what is an organelle
a small organ essential for life eg mitochondria, nucleus
what is an inclusion
dispensable eg glycogen store
what is the cytoskeleton made up of
microfilaments, intermediate filaments and microtubules
what are microfilaments
made by actin, dynamic
what are intermediate filaments
bind intracellular elements together
what are microtubules
hollow tubes made from tubulin subunits a + B, origonate from centrosome
what do dyein and kinesin do
attach to microtubules and drag things with them
what is the nuclear envelope
space between 2 membranes, called perinuclear cistern filled with water
what is the outer membrane of the nucleus like
studded with ribosomes
what is euchromatin and where is it
DNA that is dispersed and undergoing transcription
what is heterochromatin and where is it
DNA that is highly condensed and not undergoing transcription
what is endoplasmic reticulum
inside cytoplasm membrane, connects organelles, flattened fluid membrane
what is rough ER
studded with ribosomes, synthesis of proteins and initiation of glycoprotein formation
what is smooth ER
continues making proteins from rough ER and rough lipids
what is the golgi complex
composed of flat, membrane bound cisternae, packages and modifies stuff
what does the inner membrane of the mitochondria fold to form
cristae, to increase SA
what is the only other part of the cell that has DNA apart from nucleus
mitochondrion
what do occluding junctions do
prevent diffusion from touching cells (AKA tight or zonula occludens)
what do anchoring junctions do
link membrane actin filament to adjacent celss,
what do desomosomes do
link cells
what do communicating junctions do
allow selective diffusion of molecules between adjacent cells, creating pores/ channels. AKA gap junctions
describe the stages of microscopy
1) tissue preserved (eg formalin) 2) cut v thin slices 3) support materials - dehydrate, solvent and hot wax 4) cut onto microtone and rehydrate 5) changes called artefacts 6) use stains to identify (H&E)
what do epithelial cells cover
body surfaces (in and out)
what shape can epithelial cells be
squamous, cuboidal, columnar. single layered, stratified or pseudostratisfied
in endocrine glands, which end does stuff diffuse from
near basal end and diffuse into capillaries
in exocrine glands what happens
secrete towards apical ends and leave via ducts
name some soft connective tissues
tendons, ligaments (dense), dermis of skin (soft)
name some hard connective tissue
cartilage, bone
what are the 3 types of cartilage
hyalnie, elastic and fibrocartilage
is cartilage or bone avascular
cartilage, bone has Haversian channels
in connective tissue there is a large amount of extracellular space and cells, what is in there?
fibre, fluid, fibroblasts, adipose, osteocytes and chondrocytes
what fibres do muscle cells have lots of
contractile
what is smooth muscle
involuntary, smooth and no striations,
what is skeletal muscle
voluntary and striated, long and multinucleated
what do cardiac muscles look like
striated, one nucleus, intercalated discs
what do nerve tissue look like
neurones and support cells (glia), surrounded by connective tissue
what do neurones look like and what types are there
think bodies (dendrites) with a main body (soma). astrocytes oligodendrocytes and microglia
what are the 4 basic types of cells
epithelial, muscle, connective and nervous
what is the tunica intima
inner layer of blood vessel , single layer of epithelial cells supported by basal lamina and connective tissue
what is the tunica media
middle layer, smooth muscle
what is the tunica adventitia
outer layer, made by supporting connective tissue
where is the inner and outer elastic membrane
inner between intima and media, outer between intima and adventitia
in large arteries what is the tunica media replaced with and why
elastic fibres, to stop pressure building up
what are capillaries and the 3 types
endothelial and basal lamina, continous, fenestrated and discontinous
where to capillary networks drained too
post-capillary benules
describe the structure of veins
tunica intima, think media and thick adventitia. have valves
what is the lymphatic system
train excess fluid to blood, no central pump but valves
how is blood separated
centrifuge: plasma on top serum on bottom
how big are erythrocutes
7 microm, no nucleus
how long to erythrocytes live for
4 months
name the types of white blood cells
neutrophils (most common), eosinophils, basophils (rare). monocytes, lymphocytes
what are platelets
cell fragments involved in haemostasis, no nucleus
what are megakartyocytes
large cells of bone marrow that produce platelets
