IMMS Flashcards

1
Q

What colour do nerve cells stain?

A

Shades of brown

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What cells are in the spinal cord?

A

Within the spinal cord are some motor neurons. These are some of the largest cells in the body (see image below).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What do motor neurones show?

A

Motor neurons in the ventral horn of the spinal cord showing axons or dendrites arising from them. These are described as multipolar cells because when seen whole they have more than two processes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are lymphocytes like?

A
  • among the smallest nucleated cells in the body
  • circulate in the blood and are found in large numbers in organs such as in lymph nodes, the tonsils and the thymus gland
  • Many tissues also have lymph nodules full of lymphocytes within their fabric.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What can the lymph node be stained with?

A

Part of a lymph node stained with H&E showing many small lymphocytes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the nucleus of lymph nodes stain?

A

The nuclei of these cells stain dark blue but their cytoplasm is very scanty

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which dyes are used to stain?

A

two dyes, haematoxylin and eosin. This is often referred to as H&E staining.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What colour does H&E stain?

A

Haematoxylin stains cell nuclei blue and eosin stains cell cytoplasm and many extracellular fibres pink.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does the dark blue stain of a cell nucleus show?

A

The cell nucleus that stains dark blue with haematoxylin can tell you a lot about the metabolic activity of a cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does the size of the cell nucleus show?

A

A large cell nucleus often denotes a highly active cell whereas a thin or small nucleus in which it is difficult to see any of the infrastructure often denotes a relatively dormant cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is thyroid histological image like?

A

Image shows:
• roughly circular structures (in 2D – spheres in 3D)
•Each lined by a single layer of cuboidal/columnar epithelial cells
•Centre of each structure is acellular, filled with a homogenous eosinophilic material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are tissue slices size?

A

Thinner than a cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the most common dye?

A

Haematoxylin and Eosin (H&E).

Many extra cellular fibres e.g. collagen,elastic stain pink

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does not stain?

A

Watery extra-cellular jelly does not stain at all

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the other stain?

A

PAS - sugars
Van Gieson - elastic
Trichromatic - 3 types of cell
Alcian blue - mucins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the size of lymphocytes?

A

Small cells – lymphocytes about 10 micrometres in diameter, with very little cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the size of motor neurones?

A

Large cells – motor neurons 100 micrometres wide with axons up to 1 meter in length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the shapes of cells?

A

Rounded
Polygonal
Fusiform
Squamous (flattened)
Cuboidal
Columnar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How does metabolic activity relate to size of cell?

A

Inactive/dormant cells are smaller
Metabolically active cells often have nucleoli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What cells last days, months, years?

A

Days: lining of the gut

Months: lots of tissues –
blood
skin
connective tissues

Years: bone and tendons

Nearly whole life: (limited regeneration) skeletal muscle

Whole life: nerves and brain
cardiac (heart) muscle
germ cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does the nucleus contain?

A

Euchromatin
Heterochromatin
Nucleolus

Double nuclear membrane
DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What occurs at the nucleolus?

A

1-3 microns in diameter

Site of ribosomal RNA formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the mitochondria like?

A

Powerhouses of the cell

Site of oxidative phosphorylation

Have their own DNA

Double membrane – inner membrane is

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What occurs at the outer and inner membrane of the mitochondria?

A

Outer:Lipid synthesis
FA metabolism

Inner: Respiratory chain
ATP production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What occurs in the matrix and intramembranous space of the mitochondria?
Matrix - TCA (Krebs') cycle Intermembranous space - Nucleotide phosphorylation (ADP to ATP)
26
What occurs in the matrix and intramembranous space of the mitochondria?
Matrix - TCA (Krebs') cycle Intermembranous space - Nucleotide phosphorylation (ADP to ATP)
27
What occurs at the RER?
Site of protein synthesis Highly folded flattened membrane sheets
28
What occurs at the SER?
Site of membrane lipid synthesis Processes synthesised proteins Highly folded flattened membrane sheets
29
What occurs at the Golgi apparatus?
Parallel stacks of membrane Processes macromolecules synthesised in the ER Particularly prominent in Plasma cells – seen as a perinuclear ‘hoff’
30
What are the faces of the Golgi apparatus?
Cis face - nuclear-facing receives transport vesicles from SER phosphorylates some proteins Trans Golgi network Proteolysis Sorts macromolecules into vesicles which bud from the surface Medial Golgi Central part Forms complex oligosaccharides by adding sugars to lipid and peptides
31
What are vesicles?
Very small spherical membrane-bound organelles used for transport, storage and exchanging cell membrane between compartments
32
What are the types of vesicles?
Several types: Cell-surface derived pinocytotic and phagocytotic vesicles Golgi-derived transport vesicles ER-derived transport vesicles Lysosomes Peroxisomes
33
What are lysosomes like?
Derived from Golgi apparatus H+-ATPase on membrane creates low internal pH (pH 5) Contain acid hydrolases that degrade proteins Initial hydrolase vesicles fuse with endosomes with the correct membrane proteins to produce endolysosomes
34
What are perioxosomes like?
Small (0.5-1.0 microns) membrane-bound organelles containing enzymes which oxidise long-chain fatty acids
35
What is the cytoskeleton composed of?
Plasma membrane Microfilaments Mitochondrion Intermediate filaments Endoplasmic reticulum Microtubule Vesicle
36
What are the microfilaments like in the cytoskeleton?
Microfilaments - 5nm diameter ACTIN Globular G-actin polymerises into filamentous F-actin Forms a bracing mesh (cell cortex) on the inner surface of the cell membrane
37
What are the micro tubules in the cytoskeleton like?
Microtubules - 25nm diameter TUBULIN proteins All cells except erythrocytes Made of α- and β-tubulin which arrange in groups of 13 to form hollow tubes
38
What are the micro tubules in the cytoskeleton like?
Microtubules - 25nm diameter TUBULIN proteins All cells except erythrocytes Made of α- and β-tubulin which arrange in groups of 13 to form hollow tubes
39
What is the intermediate filaments in the cytoskeleton like?
Intermediate filaments - 10nm diameter - 6 types of protein - Anchored to transmembrane proteins - Spread tensile forces through tissues - Specific functions generally not known - Useful to tell one cell type from another
40
What are the localisation of intermediate filaments in the cytoskeleton?
Cytokeratins - Epithelial cells Desmin - Myocytes Glial fibrillary acidic protein - Astrocytic glial cells Neurofilament protein - Neurons Nuclear laminin - Nuclei of all cells Vimentin - Mesodermal cells
41
What are the localisation of intermediate filaments in the cytoskeleton?
Cytokeratins - Epithelial cells Desmin - Myocytes Glial fibrillary acidic protein - Astrocytic glial cells Neurofilament protein - Neurons Nuclear laminin - Nuclei of all cells Vimentin - Mesodermal cells
42
What are lipofuscin?
Lipofuscin Membrane-bound orange-brown pigment Peroxidation of lipids in older cells Common in heart and liver
43
What are lipids and glycogen like?
Lipid Non-membrane-bound vacuoles Appear as empty space as dissolve in processing Adipocytes and liver Glycogen CHO polymer in cytoplasm Normally only seen on electron microscopy Accumulates in some cells & diseases
44
What is the composition of tissues?
Cells Interstitial fluid water salts in solution peptides and proteins (e.g. plasma proteins, hormones, etc.) Extracellular material Fibrillary proteins – e.g. tendons Glycosaminoglycan jelly inorganic salts as solids
45
What are the types of tissue?
Epithelia - protection, absorption, secretion Muscle - smooth, skeletal, heart Supporting tissues - cartilage, bone, tendons, blood Nerves - brain, peripheral, visceral Germ cells - ova, sperm
46
What are epithelia?
Epithelia comprise a cohesive sheet of cells, with one or more layers, resting on a basement membrane.
47
What are epithelia found?
Form barriers for: Protection – e.g. skin Absorption – e.g. gut Secretion – e.g. pancreas
48
How are epithelia categorised?
Categorised according to the shape of the cells and the number of layers of cells.
49
What is simple epithelia and stratified (compound) epithelia?
Simple epithelia Single layer of cells on a basement membrane Stratified (compound) epithelia Two or more layers of cells on a basement membrane
50
What is simple squamous epithelium?
- Single layer of flattened plate-like cells on a basement membrane - Parallel oval nuclei (1 per cell)
51
Where is simple squamous epithelium found?
Lines inside of blood vessels (endothelium), outside of lungs (mesothelium) and abdominal organs (peritoneum) E.g. lung alveoli
52
What is simple cuboidal epithelium?
- Single layer of cells with similar height and width on a basement membrane - Central spherical nuclei (1 per cell)
53
Where is simple cuboidal epithelium found?
- Line kidney tubules, small ducts E.g. salivary glands and kidney
54
What are simple columnar epithelium?
Single layer of cells taller than they are wide, on a basement membrane Line the stomach, intestines and uterus May or may not have cilia or microvilli
55
Where is simple columnar epithelium found?
Stomach and small intestine
56
What are mivrovilli?
Microscopic projections on luminal surface of absorptive cells - Increase surface area - Intestinal brush border E.g. small intestine
57
What are cilia?
Microscopic motile projections on luminal surface of cells Respiratory tract Reproductive tract e.g. trachea, fallopian tube
58
What are stratified epithelia? Where are they?
Features Protective function Many layers of cells Continually being worn down, worn-away cells replaced from below Locations Found at sites subject to abrasive forces e.g. pigmented skin
59
What is stratified squamous non-keratinising epithelium?
Multiple layer of cells on a basement membrane Mature surface layers are plate-like squames - Lines the mouth, oropharynx, oesophagus, vagina
60
What is stratified squamous keratinising epithelium?
Multiple layer of cells on a basement membrane Mature surface layers are plate-like squames Waterproof layer of keratin Skin
61
What is pseudostratified epithelium?
Single layer of cells of variable height, mimicking multiple layers on a basement membrane All cells in contact with basement membrane Lines the conducting airways
62
What is urothelium?
Specialises stratified epithelium Breaks the rules – looks stratified, probably is stratified, but: Surface layer of umbrella cells Cells between …
63
What is the basement membrane?
Always present – usually cannot see it Infer presence – difference between epithelium and underlying connective tissue
64
What is the basement membrane composed of?
Composed of several extra-cellular proteins including Collagen IV and Fibronectin Essential for the proper functioning and survival of the epithelium Can be seen if stained with PAS
65
What are the types epithelial junctions?
Occluding (tight) junctions Desmosomes (Anchoring/Adherent junctions) Gap (aka communicating) junctions
66
What are tight/occluding junctions like?
Band-like fusions between cells that are impervious to most molecules Prevent diffusion between cells
67
What are desmosomes (anchoring/adherent) junctions?
Plaques that form physical joins between cells and connect the cytoskeletons of adjacent cells Spread forces across several cells
68
What are gap/communicating jucntions?
Electrical junctions that permit the transfer of small molecules Electrically couple adjacent cells
69
What do epithelia comprise?
Epithelia comprise one or more layers of cells resting on a basement membrane
70
When aren’t basement membranes not visible?
Basement membrane not usually visible in H+E stained sections
71
What do specialised junctions do?
Specialised junctions connect the epithelial cells together.
72
What is the origin of connective tissue cells?
Mainly derived from undifferentiated mesenchymal cells fibroblast fat cells most cartilage and bone cells But also from the haematopoetic stem cell line
73
What can mesenchymal cells become?
Mesenchymal cell - adipocyte (white adipose tissue) - adipocyte (brown adipose tissue) - osteoblast -> osteocyte - mast cell - fibroblast -> fibrocyte - chondroblast -> chondrocyte
74
What are the constituents of connective tissues?
Cells: fibroblasts/cytes adipose cells Visible fibres: collagen elastic reticulin Ground substance (hydrophilic jelly) Proteoglycans Glycosaminoglycans (GAGS) Laminin, fibronectin etc (invisible fibres)
75
What are the types of connective tissue?
Fibrous - loose, dense Hard - cartilage, bone Fatty - white, brown
76
What is collagen like?
Tropocollagen - triple helix of peptides Fibroblasts - secrete tropocollagen subunits Fibres - assembled extra-cellularly Triple helix of peptides -> overlapping tropocollagen units -> collagen fibril
77
What are the types of collagen?
More than 20 types : Type 1 skin 2 cartilage 3 liver bone marrow spleen (reticulin) 4 basement membranes 5 placenta
78
What are collagen fibres like?
Extracellular Fibres that stain pink with H&E Variable thickness and length, often run in bundles Sometime confused for muscle fibres that also stain pink (but are intra-cellular)
79
What are collagen fibres like?
Extracellular Fibres that stain pink with H&E Variable thickness and length, often run in bundles Sometime confused for muscle fibres that also stain pink (but are intra-cellular)
80
What comprises loose connective tissue?
Comprises: Widely spaced thin collagen fibres Fibroblasts/fibrocytes Unstained ground substance
81
What comprises dense connective tissue?
Comprises: Closely spaced thick collagen fibres Fibroblasts/fibrocytes Unstained ground substance May be irregular (top) or regular (bottom)
82
What is reticulin?
Type III collagen Fibrillar collagen Forms a supporting scaffold in many organs Bone marrow Liver, Kidney Lymph node Spleen Not visible on H+E – need a silver stain
83
What is elastin like?
Elastic tissue contains fine fibres and sheets of elastin Elastin fibres may be branched Produced by fibroblasts Stain pink on H+E Easily confused with smooth muscle cells
84
What is white adipose (fatty) tissue like?
Large cells with single fat globule in each cell Usually appear empty (white) in conventional slides as fat is extracted during processing Don’t confuse it with lung!
85
What is brown adipose (fatty) tissue like?
Cells with many globules of fat. Found across shoulders and down back of newborn. Important in neonatal thermo-regulation (generate heat on breakdown)
86
What are the constituents of cartilage?
Cells –Chondroblasts –Chondrocytes •Extracellular matrix –Glycosaminoglycans •Hyaluronic acid –Proteoglycans •Condroitin sulphate •Keratan glycan Extracellular fibres - collagen - elastin Cartilage is avascular
87
What is hyaline cartilage like?
Found in synovial joints •Chondrocytes in lacunae surrounded by a glassy amorphous matrix •No visible fibres •Perichondrium – fibroblasts and collagen
88
What is in elastic cartilage?
Found in the pinna, epiglottis •Visible elastic fibres in matrix •Perichondrium – fibroblasts and collagen
89
What is fibrocartilage like?
Found in the annulus fibrosus, pubic symphysis •Visible collagen fibres in matrix •Perichondrium – fibroblasts and collagen
90
What is synovium?
Lines the inside of the joint capsule •1-4 layers of synovial cells •Type A – phagocytes •Type B – rich in rER •Variable shapes – squamous to cuboidal •Richly vascular, highly innervated
91
What are muscle types?
Visceral (smooth) muscle arterial wall, wall of intestine airways of lungs Voluntary (skeletal) muscle skeletal muscles, larynx diaphragm Cardiac muscle heart base of great vessels Other contractile cells pericytes, myo-fibroblasts myo-epithelial cells
92
What is smooth muscle like?
Involuntary muscle Fusiform cells Central nucleus No striations Non-branching
93
Where do connective tissues arise from?
Connective tissue cells arise from mesenchymal cells and haematopoetic cells
94
What do fibroblasts produce?
Fibroblasts produce collagens (many types, with different functions), elastins and other proteins
95
What are the histology of adipocytes?
96
What is cartilage made up of?
•Cartilage comprises chondrocytes and extracellular matrix
97
What are chondrocytes from?
Chondrocyres derived from chondroblasts derived from mesenchymalme. Fibre content in matrix varies between cartilage types?
98
What are the three types of muscle?
Three types of muscle: smooth, skeletal, cardiac with distinct histological appearances
99
What is the structure of arteries?
Inside: - Lumen - Endothelium - basement membrane - intima - internal elastic laminate - media - external elastic lamina - adventitia Outside
100
What are the elastic arteries?
Arteries near the heart e.g. aorta, pulmonary arteries Media contains abundant concentric sheets of elastin (seen here as thin red lines)
101
What are muscular arteries like?
Most arteries are muscular arteries Media comprises layers of smooth muscle Little elastin in the media e.g. radial artery, splenic artery
102
What are muscular arteries like?
Most arteries are muscular arteries Media comprises layers of smooth muscle Little elastin in the media e.g. radial artery, splenic artery
103
What is the general structure of capillaries?
Inside: - Lumen - endothelium (inside b.m) - basement membrane Outside: - Pericytes Fenestrated capillaries - endothelium incomplete
104
What are capillaries like?
Composed entirely of thin-walled endothelial cells with no surrounding muscle or connective tissue. Most tissues have closed capillaries but some tissues (e.g. kidney & liver) have more “leaky” fenestrated ones
105
What is the general structure of veins?
Inside: Lumen Endothelium Intima Basement membrane Internal elastic lamina Media Adventitia? Outside: Check
106
What are venules like?
Associated with arterioles Thin walled Contractile pericytes wrap around outside of endothelial cells and form a complete layer as venules get larger. Pericytes replaced by smooth muscle as venules become veins
107
What are venules like?
Associated with arterioles Thin walled Contractile pericytes wrap around outside of endothelial cells and form a complete layer as venules get larger. Pericytes replaced by smooth muscle as venules become veins
108
What are veins like?
Large veins are thick walled (compared to venules) Thin walled compared to corresponding artery Smooth muscle in wall may be circular or longitudinal
109
What are lymphatics like?
Thin walled, similar to capillaries and veins Have valves Do not contain blood Contains eosinophilic lymph and may contain lymphocytes
110
What are the peripheral nerves like?
Composed of axons Supported by Schwann cells Most are myelinated – insulating sheath Myelin produced by Schwann cells
111
What is the structure of a peripheral nerve?
?
112
What is in a myelinated peripheral nerve?
Endoneurium Present between individual axons Perineurium Surrounds the groups of axons to form fascicles Epineurium Binds fascicles together to form nerve fibres
113
What are small peripheral nerve fibres?
Bundle of axons interspersed with endoneurium and surrounded by perineurium and epineurium Myelinated axons Endoneurium Perineurium Epineurium
114
How is an artery diff to a vein?
Arteries have Thicker walls and smaller lumen than veins
115
What is myelin formed by?
Schwann cell wrapping around axon One myelinated axon per Schwann cell, multiple Schwann cells per myelinated axon Multiple unmyelinated axons per Schwann cell, multiple Schwann cells per unmyelinated axon