ToB Flashcards
0
Q
Define histology
A
Study of the structure of tissues by means of special staining techniques combined with light and electron microscopy
1
Q
Define tissue
A
Collection of cells specialised to perform a particular function
Aggregations of tissues constitute organs
2
Q
Value of histology
A
Biopsy and histology is the final proof of most diseases
For diagnoses purposes
E.g. Lung and breast cancer
3
Q
Angstrom in meters
A
10^-10 m
4
Q
Size of most cells
A
10-20micrometers
5
Q
Define biopsy
A
Removal of a small piece of tissue from an organ or part of the body for microscopic examination
6
Q
Define smear test
A
Collect cells by spontaneous/mechanical exfoliation
7
Q
What is a smear test used for?
A
Cervix and buccal cavity
8
Q
Define curettage
A
Remove tissue by scooping and scraping
9
Q
Define needle
A
Put needle into tissue to gather cells
10
Q
Define direct incision
A
Cut directly into tissue of interest and remove tissue
11
Q
Define endoscopic
A
Removal of tissue via instruments through an endoscope
12
Q
Uses of curettage
A
Endometrial lining of uterus
13
Q
Uses of needle biopsy
A
Brain Breast Liver Kidney Muscle
14
Q
Uses of direct incision
A
Skin
Mouth
Larynx
15
Q
Uses of endoscopy
A
Lung
Bladder
Intestine
16
Q
Uses of trans vascular biopsy
A
Heart
Liver
17
Q
Fresh biopsy examples
A
Needle biopsy
Wet and bloody
18
Q
Define fixed biopsy
A
Macromolecules cross-linked
Cellular structure preserved
No autokysis or putrefaction
19
Q
Commonly used fixatives
A
Glutaraldehyde
Formaldehyde
20
Q
What causes shrinkage artefacts
A
Tissue is dehydrated and rehydrated in
Slide preparation process
21
Q
What is a shrinkage artefact?
A
Abnormalities in final slide
22
Q
What does haematoxylin stain?
A
Acidic components of cells
Nucleolus (RNA)
Chromatin (DNA)
Purple/Blue
23
Q
What does eosin stain?
A
Basic components of cells
Most cytoplasmic proteins
Extracellular fibres
Pink
24
What does Periodic Acid-Schiff stain?
Carbohydrates
Glycoproteins
Magenta
25
What is phase contrast?
Uses interference effects of two combining light waves
26
Advantages of phase contrast
Enhancing the image of unstained cells
27
Define dark field
Exclude unscattered beam (light/electron) from the image
28
Advantages of dark field
Live an unstained sample
29
Define fluorescence
Target molecule of interest with fluorescent Ab
30
Define confocal
Tissue labelled with one or more fluorescent probes
31
Advantaged of fluorescence
Uses multiple fluorescent stains on one specimen
32
Advantages of confocal
Eliminates 'out of focus flare'
3D from a series of 2D images
Imaging of living specimens
33
Define epithelia
Sheets of contiguous cells of varied embryonic origin that cover external surface of the body and line internal surfaces
34
Embryonic origin of epidermis and corneal epithelium
Ectoderm
35
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Embryonic origin of
epithelium of urogenital tract
Blood and lymphatic vessel lining
Pericardial and pleural sac lining
Peritoneal lining
```
Mesoderm
36
Embryonic origin of
| Epithelia of resp and GI tract, of liver and many glands
Endoderm
37
Define simple
One cell layer thick
38
Define endothelium
Lining of blood vessels
39
Define mesothelium
Lining of body cavities
| Pericardium, pleura, peritoneum
40
Epithelia of blood vessels
Simple squamous
41
Epithelia of mesothelium
Simple squamous
42
Basement membrane position
Thin, flexible, acellular layer which lies between epithelial cells and subtending connective tissue
43
Basement membrane structure
Basal lamina laid down by epithelial cells, lies closest to them
Thickness can inc by variably thick layer of reticular fibrils (type3collagen) elaborated by the subtending connective tissue
44
Basement membrane function
Strong flexible layer to which epithelial cells adhere
Cellular and molecular filter
Degree of penetration of basement membrane by malignant cells highly relevant to prognosis
45
Where are micro villi occludin?
Simple columnar epithelia
46
What does microvilli occludin do?
Binds adjacent plasma membranes tightly together in apical portions of some epithelia
Form zona occludens
Membrane proteins cannot pass
47
Renewal rate for epithelia
| Describe
Constant rate for each epithelia
| Differs depending on location and fUnction
48
When is turnover rate of epithelia not constant?
Injury leads to acceleration
49
Turnover rate of skin
28 days
50
Turnover rate of small intestine epithelia
4-6 days
51
Are all epithelia renewed?
No
| But proliferation can be triggered to replace damaged/lost cells
52
Define microvilli
Apical extensions that greatly increase the surface area for selective absorption of intestinal contents
53
Define stereocilia
Very long microvilli
Extend from the surface of the ductus deferens and the epididymis
May have absorptive function
54
Define cilia
Extensions form cells that beat in coordinated waves
| 9+2 configuration
55
Where are cilia found ?
In lining of trachea - sweep mucus n dirt out of lungs
| In Fallopian tubes - move ovum from ovary to uterus
56
Classifying glands
Destination of secretion
Structure of gland
Nature of secretion
Method of discharge
57
Define exocrine
Gland with ducts
58
Define endocrine
Ductless gland that secretes directly into the blood
59
Simple multicellular glands
Ducts don't branch
60
Complex/compound multicellular gland
Ducts branch
61
Define mucous gland
Secretions containing mucus rich mucins
highly glycosylated polypeptide
Such cells stain poorly in H&E sections
62
Define serous glands
Secretions often enzymes are watery and free of mucus
| Eosinophilic pink H and E section
63
Methods of secretion
Merocrine
Apocrine
Holocrine
64
Describe Merocrine secretion
Membrane bound vesicle approaches cell-surface
Vesicle fuses with plasma membrane
Contents of vesicle are in continuity with the extracellular space
Plasma membrane is very slightly larger
Membrane retrieved stabilising cell-surface area
65
Examples of merocrine secretion locations
Salivary glands
| Pancreas
66
Examples of apocrine secretion locations
Mammary glands
| myoepithelial cells assist secretion
67
Describe Apocrine secretion
Non-membrane-bound structures e.g. Lipid approaches cell-surface
Make contact and pushes up apical membrane
Thin layer of apical cytoplasm drapes around droplet
Menbrane surrounding droplet pinches off from cell
Plasma membrane is very slightly smaller
Membrane added to regain original surface area
68
Location of Holocene secretion
Sebaceous gland
69
Describe Holocene secretion
Disintegration of the entire cell
Release of contents
Discharge of whole cell
70
Define endocytosis
Process of engulfing material initially outside the cell
| Opposite to exocytosis (merocrine secretion)
71
What is coupled in trans epithelial transport?
Endocytosis and exocytosis
72
When is trans epithelial transport used?
When molecules are too large to penetrate membranes
73
Describe trans epithelial transport
Material endocytosis at one surface of the cell
Transport vesicle shuttles it across the cytoplasm
Material/vesicle then exocytosis at the opposite surface
74
Golgi apparatus structure
Stack of disc-shaped cisternae
One side of the disc flattened, other side concave
Discs have swelling at their edges (vesicles that bud off)
Distal swellings pinch off as migratory Golgi vacuoles
75
Golgi apparatus function
Sorting into different compartments
Packaging through condensation of contents
Adding sugars to proteins and lipids (glycosylation)
Transport
76
Golgi apparatus product destination
Majority extruded in secretory vesicles
Some retained for use in cells (e.g. Lysosomes)
Some enter the plasma membrane (Glycocalyx)
77
Golgi apparatus - glycosylation and specificity
Branching sugars offer complex shapes for specific interaction in the Glycocalyx
Enzymatic destruction of this layer alters specificity based properties of cells
78
Specificity based properties of cells determined by Glycocalyx
Adhesion to substrates and neighbouring cells
Communication with neighbouring cells
Contact inhibition of movement and division
Mobility of cells
79
What makes cells more specific?
Sugars
80
Simple mechanisms that control secretion
Nervous control
Endocrine control
Neuro-endocrine control
Negative feedback chemical mechanism
81
Example of nervous control of secretion
Sympathetic nervous stimulation of adrenal medullary cells
| Leads to release of adrenaline
82
Example of endocrine control of secretion
Adrenocorticotrophic hormone ACTH stimulate the cortex of the adrenal gland to secrete hormones
E.g. Cortisol
83
Example of neuro-endocrine control of secretion
Nervous cells of the hypothalamus control ACTH secretion from the anterior pituitary gland
84
Example of negative feedback chemical mechanism of secretion
Inhibitory effect of high thyroxine (T3&T4) levels on TSH synthesis by the anterior pituitary gland
85
Recognising exocrine gland
Unicellular glands (goblet cells) in jejunum and colon
Parotid glands
Submandibular glands
86
Recognise endocrine glands
Pancreas
Thyroid gland
Parathyroid gland
Adrenal (suprarenal) glands
87
Secretion by parotid glands
Exocrine
88
Secretion by submandibular glands
Exocrine
89
Secretion by pancreas
Endocrine
90
Secretion by thyroid glands
Endocrine
91
Secretion by parathyroid glands
Endocrine
92
Secretion by adrenal (suprarenal) glands
Endocrine
93
What do mucous membranes line?
Internal tubes that open to the exterior
Alimentary tract
Respiratory tract
Urinary tract
94
Mucous membranes consist of:
Epithelium (type depending on site) lining the lumen of a tube
Adjacent layer of connective tissue often referred to as the lamina propria
In the alimentary tract, 3rd layer consisting of smooth muscle= muscular is mucosae
95
Muscularis mucosae
What is the smooth muscle in alimentary tract also known as?
96
What is the adjacent layer if connective tissue in mucous membrane also known as?
Lamina propria
97
What are serous membranes?
Thin, two part membrane that line certain closed body cavities (spaces which do not open to the exterior)
98
What do serous membranes envelop?
The viscera
99
Examples of serous membranes
Peritoneum
Pleural sacs
Pericardial sac
100
What does the pericardial sac envelop?
The heart
101
What does the peritoneum envelop?
Many abdominal organs
102
What do the pleural sacs envelop?
The lungs
103
What do the serous membranes secrete?
Lubricating fluid
| Promotes relatively friction free movement of structures they surround
104
Serous membrane consists of:
Simple squamous epithelium (mesothelium)- secretes watery lubricating fluid
Thin layer of connective tissue - attaches to epithelium to adjacent tissues (also carries blood vessels and nerves)
105
Define the term limit of resolution
Minimum distance that two objects can be distinguished at
106
Limit of resolution is proportional to
Wavelength
107
Theoretical limit of resolution for light microscope
0.2 micrometers
108
Theoretical limit of resolution for an electron microscope
0.002nm
109
Structure of bilipid membrane
```
Phospholipid bilayer (membrane) forms a relatively impermeable barrier to most water-soluble molecules
Phospholipid molecules which make up cell membrane are amphipathic
```
110
Function of bilipid membrane
Protein molecules dissolved in the lipid bilayer mediate most of the other functions of the membrane
111
Structure of Glycocalyx
Cell 'coat' made up of oligosaccharide and polysaccharide side chain on the outside of the plasma membrane
112
Function of Glycocalyx
Side chains are a way of giving the cell specificity
113
Functions of plasma membrane
```
Selective permeability
Transport of materials along the cell surface
Exocytosis
Endocytosis
Intercellular recognition
Signal transduction
Intercellular adhesion
```
114
Functions of nucleus
Stores cell's DNA
Coordinates cell's activities
metabolism, growth, protein synthesis, mitosis
115
Structure of nuclear envelope
Double layered membrane that separates the contents of the nucleus from the cellular cytoplasm
Has lots of nuclear pores
116
Function of nuclear envelope
Nuclear pores allow specific types and sizes of molecules to pass back and forth between the nuclear and cytoplasm
Attached to a network of tubules called the endoplasmic reticulum
117
Describe nucleolus
Inside nucleus
| Synthesises protein-producing macromolecular structures called ribosomes
118
Describe ribosome
Site of translation
| Used for protein synthesis
119
Structure of rough endoplasmic reticulum with ribosomes
Membrane of RER continuous with outer layer of nuclear envelope
Ribosome only binds when it begins to synthesise a protein destined for the secretory pathway
120
Functions of RER
Lysosomal enzymes with mannose-6-phosphate marker added in cis-Golgi network
Secreted proteins constitutively or regulated
Initial glycosylation N-linked (O- linked in Golgi)
121
Where is smooth ER found
Liver and mammary gland (lipid synthesis)
| Ovaries, testis, adrenal glands (steroidogenesis)
122
Golgi apparatus structure
Saucer shaped stacks of cisternae
123
Vesicle transport in Golgi
Vesicles bud off from the RER and fuse with the convex cis face of the Golgi body
Golgi bodies have polarity such that proteins migrate from the convex to the concave trans face of the stack
124
Functions of the Golgi apparatus
Modify, sort, concentrate and package proteins synthesised on the RER
125
Vesicles leaving Golgi
Destined for lysosomes assembly or
| Secretion - secretory vesicles are condensed to granules then contents released at cell surface by exocytosis
