foundation histology Flashcards
1
Q
what is the resolving power of light and electron microscopy
A
light = 0.2microns electron = 0.2nanometers
2
Q
what is the that you have to do to be able to look at something on a slide
A
fixation embedding sectioning rehydration put of slide with coverslip
3
Q
how do you fixate a specimen
A
put it in formalin –> chemically cross links molecules together to lock in place = toughens
4
Q
why do you fixate specimens
A
to prevent autolysis and bacterial colonization of cells
5
Q
what is the process of embedding
A
gradually dehydrate the specimen in alcohol and then xylene then molten paraffin = stiffens tissue
6
Q
how do you section a specimen
A
using a microtome
7
Q
haematoxylin binds to… and what colour
A
binds to phosphate groups of nucleic acid
blue
8
Q
eosin binds to… and what colour
A
binds to ionized amino groups of proteins
pink
9
Q
what defines a CT
A
few cells to a large mass of ECM which consists of fibres embedded in ground substance containing tissue fluid: ECF
10
Q
what is the component of CT that determines the CT “type”
A
the ECM
11
Q
what are the 4 basic tissue types
A
CT
epithelia
muscle
neural tissue
12
Q
what is the difference between parenchyma and stroma
A
parenchyma = functional cells stroma = support tissue
13
Q
CT comes from which developmental layer
A
mesenchymal stem cells of the mesoderm
14
Q
what are the 3 main groups of proteins in plasma
A
- those involved in coagulation
- albumin
- globulins
15
Q
what is the function of plasma proteins
A
exert colloid osmotic pressure
16
Q
where are plasma proteins synthesised
A
in the liver
17
Q
normal haematocrit
A
45%
18
Q
diameter of RBC
A
7.2microns
19
Q
what are reticulocytes are explain their structure
A
immature RBCs
- no nucleus but still have some organelles
20
Q
what is the normal level of reticulocytes in the blood
A
<1%
21
Q
in what situations would you see an increased level of reticulocytes
A
haemorrhage
haemolysis
22
Q
what is a normoblast
A
immature nucleated RBC
23
Q
life span of RBCs and platelets
A
RBC - 120 days
platelets - 8-10 days
24
Q
lifespan of neutrophils
A
hours
25
what does a eosinophil look like
pink with multiple granules
| - with bilobed nucleus
26
what does a basophil look like
blue with large granules
| - with bilobed nucleus
27
where is red marrow found in adults
axial skeleton and proximal femurs
28
where does fetal haemopoiesis mainly occur
in the liver
29
haemopoietic stem cells give rise to blood cells and...
osteoclasts
30
what does it mean if you see increased numbers of the following in the blood
- neutrophils
- eosinophils
- lymphocytes
```
neutrophils = acute inflammation, especially in bacterial infection
eosinophils = allergy or parasitic infection
lymphocytes = viral infection
```
31
what is a "left shift"
when immature WBCs are released into the circulation
32
main cell of CT
fibroblasts
33
3 types of fibres that make up CT
elastic
collagen
reticular
34
explain the structure of collagen
3 polypeptide alpha chains that form a triple helix
35
what are the main roles of collagen 1,2,3,4,7
```
1 = bone, tendon, ligament
2 = cartilage, IV disc
3 = reticular fibres
4 = BM
7 = anchoring fibrils that link to basement membranes
```
36
what is the function of reticulin fibres
they provide a framework for cells in certain tissues
37
explain the structure of elastin fibres
central core of elastin and surrounding network of fibrillin microfibrils
38
where is elastic fibres particularly prevalent in the body
aorta, lung, skin
39
how does Marfans syndrome affect elastin
inherited disease of fibrillin 1 needed for the assembly of elastin
40
what is ground substance
the viscous clear substance that is between the fibres of CT
| - high water content
41
explain the distribution of fluid in the body
- 2/3 IC
| - 1/3 EC (1/5 - plasma, 4/5 - interstitial)
42
what are the components of ground substance
Glycosaminoglycans
| glycoproteins
43
what is the predominant GAG of ground substance
hyaluronic acid - negatively charged - attracts Na - water follows
44
what are the glycoproteins of the ground substance
fibronectin
fibrillin
laminin
45
what is the role of the glycoproteins of the ground substance of CT
- involved in the regulation of deposition and orientation of fibres
- involved in links between cells and matrox
46
what is ECM
fibres+ground substance
47
the ECM is continuously being remodelled by
MMP and phagocytosis
48
function of fibroblasts
synthesis of ECM (fibres and ground substance)
49
what makes brown adipose tissue
multiple lipid containing vesicles in a cell
50
collagen of cartilage
2
51
what are the main components of the ECM of the basement membrane
- collagen IV
- heparan sulphate
- structural glycoproteins (laminins and fibronectin)
52
what is the function of the structural glycoproteins of the BM
involved in linking integrins of epithelial cells to ECM
53
which collagen is involved in the attachment of the BM to underlying CT
7
54
what are the functions of BM
- structural support
- control of epithelial growth
- links epithelium to underlying tissue
- selective barrier to nutrients
55
what are the 3 structural properties of CT
- tensile
- elasticity
- volume
56
which three things are connective tissue proper
bone
cartilage
BM
57
functions of surface epithelial tissue
- protection
- barrier, selective diffusion
- absorption
- secretion
58
where is simple squamous epithelium found
mesothelium
endothelium
lining of alveoli
glomeruli
59
where is simple cuboidal epithelium found
- thyroid follicles
| - renal tubules
60
where is simple columnar ciliated epithelium found
fallopian tubes
| bronchioles
61
where is simple columnar non-ciliated epithelium found
stomach, small and large intestines, gall bladder and bile ducts, endometrium, endocervix
62
where is non-keratinizing stratified squamous epithelium found
oral cavity, oesophagus, anus, vagina, ectocervix
63
where is stratified cuboidal epithelium found
some ducts
64
where is a surface columnar layer overlying myoepithelial layer found
breast
| sweat glands
65
where is a surface columnar layer overlying basal layer found
prostate
66
where is transitional/urothelium found
renal pelvis
ureters
bladder
67
cilia have a core of
microtubules
68
where are tight junctions found and what are their function
found as a continuous circumferential band around the apex of cells
- seal intercellular spaces to block the passage of substances between cells
69
where are adhering junctions and desmosomes found and what are their function
on the lateral sides of epithelial cells
| - strongly attachment between cells by linking cytoskeletons (cadherins)
70
where are hemidesmosomes and what are their function
- found on the basal side of the epithelial cell
| - link the cell to the BM
71
function of gap junctions
allow passage of small molecules, communication
72
what are the 4 main transmembrane proteins
- cadherins
- integrins
- selectins
- immunoglobulin superfamily
73
explain the connection made by adherins junctions
cytoplasmic tails of cadherins link to anchor proteins (catenins) which link to actin filaments in the cytoplasm
- cadherins link to cadherins on adjacent cell
74
explain the connection made by desmosomes
cadherins linke to anchoring proteins which bind to cytokeratin intermediate filaments in the cell
- cadherins link to cadherins on adjacent cell
75
what is the difference between an erosion and an ulcer
erosion - a local defect in a surface mucosa
| ulcer - a local defect in a mucosa
76
two types of secretion by exocrine glands
serous secretion - protein in aqueous medium
| mucous secretion - glycoprotein in aqueous medium
77
3 types of cytoskeleton
actin
intermediate filaments
microtubules
78
what is the histological appearance of skeletal muscle on cross section and longitudinal section
CS - peripheral nuclei
| LS - peripheral nuclei, striations, length
79
what is the histological appearance of cardiac muscle on cross section and longitudinal section
CS - central nuclei, thick
| LS - central nuclei, striations, branching, many capillaries, intercalated discs
80
what is the histological appearance of smooth muscle on cross section and longitudinal section
CS - central nuclei, thin
| LS - central elongated nuclei, no striations, not branched
81
what is a myofibril
contractile component of a myofibre made up of repeating units of sarcomeres
82
myosin and actin
- which is thick and which is thin
- what is their arrangement in a sarcomere
myosin - thick
actin - thin
--> actin anchored to Z disc, myosin in the middle
83
What is the function of the SR in a myofibre
- release IC Ca into cytoplasm for contraction
| - pump Ca2+ back into the lumen of the SR (rich in Ca ATPases)
84
T tubules surround...
```
each myofibril (two for each sarcomere)
- at the overlap of thick and thin filaments
```
85
function of t tubules
conduct muscle action potential into muscle cell to SR
86
what are T tubules
extensions of the cytoplasmic membrane
87
what are the 3 types of junctions in an intercalated disc of cardiac muscle
- fascia adherins
- desmosomes
- gap
88
what specific thing does SM contain that you can see on electron microscopy
dense bodies (like Z discs) - anchor actin filaments
89
which type of muscle fibre has the highest glycogen
type 2
90
how can skeletal muscle regenerate
through satellite cells
91
where are myoepithelial cells found and what is their function
surround some exocrine glands - contract via actin/myosin to squeeze out content of gland
92
function of myofibroblasts
pull wound closed
93
where are pericytes found
extend around capillaries to contract and regulate capillary blood flow
94
epineurium surrounds
perineurium surrounds
endoneurium surround
```
epi = whole nerve
per = fascicles (bundles of axons)
endo = axons
```
95
what are the types of necrosis
```
fibrinoid
coagulative
caseous
liquefactive
fat
```
96
necrosis is the type of cell death associated with
loss of plasma membrane integrity and leakage of enzymes resulting in degredation of the cell
97
histology of necrosis
- increased cytoplasmic eosinophilia
- nuclear changes
- -> karyolysis - reduced basophilia
- -> pyknosis - nuclear shrinkage and increased basophilia
- -> karyorrhexis - nuclear fragmentation
98
can necrosis by physiological
no - only pathological
99
hallmark feature of coagulative necrosis on histological section
ghost cells - cellular and tissue architecture is preserved for several days
100
coagulative necrosis is typical where
in solid organs (except the brain)
101
when is caseous necrosis found
due to necrotising granulomatous inflammation due to TB
102
histological feature of caseous necrosis
amorphous granular debris without distinct cell corders
103
macroscopic feature of caseous necrosis
looks like cheese
104
what is liquefactive necrosis
when the dead cells are digested and transformed into a viscous liquid mass or cavity
105
liquefactive necrosis is typical of what
cerebral infarction
106
when do you get fat necrosis
typical of a release of lipases due to acute pancreatitis
107
how does fat necrosis lead to saponifcation
lipases cause digestion of cell membranes --> releases TG esters --> converted to FA --> FA combine with Ca --> saponification
108
what do you see histologically with fat necrosis
- no nuclei
- granular pink eosinophilic material
- foamy macrophages (later)
109
when is fibrinoid necrosis typically seen
in association with immune reactions involving blood vessels --> leakage of fibrin --> necrosis
110
what are the 4 intracellular pigments
carbon
lipofuschin
melanin
haemosiderin
111
what is haemosiderin
large aggregates of ferritin micelles (ABNORMAL)
112
what does haemosiderin look like in H&E
large brown granules
113
what is lipofuschin
complexes of lipid and proteins associated with lysosomes that result from oxidative injury by free radicals --> accumulate with age
114
what does lipofuschin look like in H&E
insoluble yellow-brown
115
what happens to the cell size during apoptosis and necrosis
apoptosis - reduced (shrinkage)
| necrosis - enlarged (swelling)
116
what happens to the nucleus during apoptosis and necrosis
apoptosis - fragmentation into nucleosome-size fragments
| necrosis - karyolysis --> pyknosis --> karyorrhexis
117
what happens to the plasma membrane during apoptosis and necrosis
apoptosis - intact, may be released in apoptotic bodies
| necrosis - disrupted
118
is there inflammation associated with apoptosis or necrosis
apoptosis - no
| necrosis - frequently
119
principle targets of cell injury
mitochondria
calcium homeostasis
cell membranes
DNA and proteins
120
what are the 4 mechanisms of IC accumulation
- reduced removal of a normal substance (fatty liver)
- accumulation of an abnormal substance due to genetic defects effecting cellular handling (alpha1AT)
- failure to degrade a metabolite due to an inherited deficiency of an enzyme (glycogen storage disease)
- deposition of an exogenous substance which cannot be degraded by the cell (carbon)
121
what is the difference between dystrophic and metastatic calcification
dystrophic - where there has been tissue damage in some way, and occurs in these tissues that are degenerate or necrotic that are not completely removed
metastatic - can occur in normal tissue, and results due to a high blood calcium level
122
explain the death receptor (extrinsic) pathway for apoptosis
receptor ligand interactions (Fas and TNF R) --> activation of caspase -8 --> cleavage and activation of Bid --> activation of pro-apoptotic proteins Bak and Bax --> dimerisation --> insertion into mitochondrial membrane (pore) --> leakage of cytochrome c and other mitochondrial proteins into cytoplasm --> activation of caspase 9 --> caspase cascade --> breakdown of cytoskeleton and endonuclease activation --> DNA fragmentation --> apoptotic body
123
explain the mitochondrial (intrinsic pathway for apoptosis)
cell injury activates Bcl-2 family and inhibits anti-pro-apoptotic proteins --> activation of pro-apoptotic proteins Bak and Bax --> dimerisation --> insertion into mitochondrial membrane (pore) --> leakage of cytochrome c and other mitochondrial proteins into cytoplasm --> activation of caspase 9 --> caspase cascade --> breakdown of cytoskeleton and endonuclease activation --> DNA fragmentation --> apoptotic body
124
what are the main features of the necrotic pathway
- ROS
- loss of mitochondrial membrane potential
- decreased ATP
- nuclear chromatin damage
- increased cytosolic Ca
- ER and cellular swelling
- decreased protein synthesis
- Membrane damage --> leakage of enzymes
125
potential systemic signs and symptoms of inflammation
```
tachycardia
malaise, anorexia
fever, rigors, chills
weight loss
anaemia (if chronic)
```
126
blood investigations when looking for inflammation
FBE
CRP
ESR
127
what is inflammation
the protective response of living vascularised tissue to injury
128
features of acute inflammation
- neutrophils
- fluid and protein exudate
- vasodilatation
- macrophages
129
features of chronic inflammation
- macrophages
- lymphocytes
- plasma cells
- fibrosis/scarring
130
describe the vascular response to acute inflammation
- transient arteriolar constriction
- arteriolar, then capillary and venular dilation
- increased vascular permeability --> leakage of plasma proteins
- vasocongestion --> neutrophil migration
131
what causes the retraction of endothelial cells to allow migration of neutrophils
histamine, NO
132
which vessel is particularly involved in diapedesis
venules
133
dead neutrophils die by
apoptosis
134
which cytokines released by macrophages promote endothelial activation
IL-1
| TNF
135
which cytokines released by macrophages promote acute phase response
IL1, 6 and TNF
136
cardinal features of acute inflammation
```
redness
swelling
heat
pain
loss of function
```
137
3 types of acute inflammatory exudate
- purulent/suppurative - usually due to bacterial infection
- fibrinous - tend to occur on serosal surfaces
serous
138
what are the types of oedema
- transudate - occurs with normal vascular permeability (much less protein)
- exudate - occurs due to increased vascular permeability (rich in protein)
139
what is the difference between hyperemia and vasocongestion
hyperemia - active process of vasodilation
| vasocongestion - passive, due to reduced outflow of blood from a tissue
140
what cytokines mediate fever
Il-1, 6, and TNF, and PGE2
141
what mediates pain
prostaglandins and bradykinin
142
what mediates tissue damage during acute inflammation
neutrphil granule contents
ROS
NO
143
what mediates endothelial activation during acute inflammation
TNF
| IL-1
144
What mediates an increased vascular permeability during acute inflammation
histamine
serotonin
bradykinin
leukotrienes
145
what mediates vasodilatation during acute inflammation
histamine
PGE
NO
146
what are the 3 outcomes of acute inflammation
resolution
healing by repair
chronic inflammation
147
the outcome of acute inflammation depends on...
- tissue type
| - whether the cell damaged has the capacity to regenerate/replicate
148
explain resolution of acute inflammation
the damage is minimal --> dead cells regrow via cell proliferation and differentiation
149
explain in general terms healing by repair of acute inflammation
some damage to tissue --> organisation of tissue through phagocytosis, and granulation tissue formation
150
what are the 4 components of granulation tissue
- inflammatory cells (macrophages, lymphocytes)
- angiogenesis
- fibroblast migration and proliferation
- deposition of ECM (in time, more and more collagen laid down --> scar)
151
which cytokine is important for angiogenesis in granulation tissue
VEGF
152
which cytokines are important for fibroblast migration and proliferation in granulation tissue
PDGF, TGF-beta, FGF
153
what local factors can influence healing
```
movement
size, location of wound
foreign material
infection
blood flow
extensive necrosis
```
154
what are the 2 types of granulomatous inflammation
foreign body granuloma
| immune granuloma
155
granulomatous inflammation is characterized by
epitheliod macrophages and multinucleate macrophages
156
which cytokine is important in granulomatous inflammation
IFN-gamma released by T cells --> activates macrophages
