Histology Flashcards
1
Q
Where in the cell does protein synthesis occur?
A
Rough endoplasmic reticulum
2
Q
Where in the cell does cholesterol and lipid synthesis/detoxification occur?
A
Smooth endoplasmic reticulum
3
Q
Where are secretions modified and packaged?
A
Golgi apparatus
4
Q
Where is the genetic code of the cell found?
A
Nucleus
5
Q
Where are ribosomes produced?
A
Nucleolus
6
Q
Which protein are microfilaments composed of?
A
Actin
7
Q
Which proteins are microtubules composed of?
A
tubulin
8
Q
What are the features of microfilaments?
A
Composed of fine strands of actin
Dynamic - assemble and dissociate
9
Q
What function do intermediate filaments perform?
A
Binding of intracellular elements together and to the plasmalemma
10
Q
How are intermediate filaments used in pathology?
A
Different classes can be used to identify tumour origins
11
Q
What is the organising centre of microtubules known as?
A
The centrosome
12
Q
How are microtubules organized?
A
Polymerize in central portion of cell and radiate outwards
13
Q
What is the function of microtubules?
A
Transport network
14
Q
Which ATPase moves organelles and vesicles towards the centre?
A
Dynein
15
Q
Which ATPase moves organelles and vesicles towards the periphery?
A
Kinesin
16
Q
What is the structure of the nuclear envelope?
A
Outer nuclear membrane with nuclear pores, studded with ribosomes
Perinuclear cistern
Inner nuclear membrane
17
Q
What structure is the outer nuclear membrane continuous with?
A
Rough Endoplasmic Reticulum
18
Q
Where are mRNA and tRNA transcribed?
A
Nucleus
19
Q
Where is rRNA transcribed?
A
Nucleolus
20
Q
What is the difference between euchromatin and heterochromatin?
A
Euchromatin is DNA that is actively undergoing transcription, heterochromatin is condense
21
Q
What is the structure of ribosomes?
A
Small subunit which binds RNA
Large subunit which catalyses formation of peptide bonds
22
Q
How do ribosomes stain with H&E?
A
Blue (because of negative charges)
23
Q
What makes the Rough Endoplasmic Reticulum rough?
A
It is studded with ribosomes, which are used for protein synthesis
24
Q
What does the amount of RER in a cell tell us about its activity?
A
The more metabolically active a cell, the greater the amount of RER
25
Where are proteins that are destined to remain unpackaged synthesized?
On polysomes, floating free within the cytosol
26
How does protein synthesis occur?
Free ribosome attaches to mRNA
If ER signal is present, growing peptide inserted into pore in the endoplasmic reticulum
Growing peptide forms in the ER, signal sequence is removed
Ribosome detaches
27
Where do proteins go once they are synthesized?
Most of them go to the Smooth Endoplasmic Reticulum
28
What happens to a protein in the Smooth Endoplasmic Reticulum?
Continued processing
29
From where do transport vesicles arrive in the Golgi apparatus?
Smooth Endoplasmic Reticulum
30
What sort of modifications are made in the Golgi apparatus?
Addition of sugars
Cleavage of proteins
31
How is the inner membrane of the mitochondria folded?
Into cristae
32
What are the functions of the mitochondria?
Generation of ATP by oxidative phosphorylation
Synthesis of certain lipids and proteins
33
Give an example of an inclusion.
Lipid droplets - they are not surrounded by a membrane
34
In which type of cells may lipids droplets make up 90% of the cell volume?
Adipose cells
35
Which molecules bind to each other and to actin of the cytoskeleton?
Cadherin molecules
36
What are hemidesmosomes?
Junctions which link intermediate filaments of a cell to the extracellular matrix through transmembrane proteins
37
Which type of protein forms the pores in gap junctions?
Connexon proteins
38
What are the four basic tissue types?
Epithelium
Connective tissue
Muscle
Nervous Tissue
39
Where are epithelia found?
Covering body surfaces
Lining hollow organs
Forming glands
40
What are the roles of connective tissue?
Forming the framework of the body
Dynamic role in development, growth and homeostasis of tissues
Energy storage as fat
41
What are the common features of epithelia?
Strong adhesion between cells forming sheets
Basal lamina - extracellular matrix
Non-vascular - nutrients diffuse across basal lamina
Polarised - apical and basal ends of cell differ
42
Give an example of a solid gland formed from epithelia.
The liver.
43
What are the functions of epithelia?
Mechanical barrier
Chemical barrier
Absorption
Secretion
Containment
Locomotion (by cilia)
44
What are the three shapes of epithelial cells?
Squamous (flattened)
Cuboidal
Columnar
45
How is the layering of epithelia described?
Simple - one layer
Stratified - two or more layers
Pseudostratified - appears to have multiple layers but all cells are in contact with the basal lamina
46
What sort of surface specializations may be found in epithelia?
Prominent microvilli (brush border)
Cilia
Keratin protein
47
What sort of specialized cells might be found in epithelia?
Goblet cells - single cell mucus glands
48
What is the function of glandular epithelia? Give some examples.
Producing secretory products.
e.g. sweat, milk, hormones, oil, mucus, enzymes
49
How are glands classified?
Endocrine - product secreted towards basal end of the cell and distributed through vascular system
Exocrine - produce secreted towards apical end of the cell either into lumen, duct or onto body surface
50
What features are characteristic of endocrine glands?
No ducts
Lots of capillaries
51
How is connective tissue subdivided into types?
Soft connective tissue - tendons, ligaments, mesentery, stroma of organs, dermis
Hard connective tissue - bone, cartilage
52
What does connective tissue consist of?
Cells
Extracellular matrix
53
What does the extracellular matrix consist of?
Collagen, reticular and elastic fibres
Ground substance - glycoproteins
Tissue fluid
54
What sort of cells might be found in connective tissue?
Fibroblasts
Adipose cells
Osteocytes/chondrocytes
55
What type of connective tissue is mesentery?
Loose connective tissue
Loosely packed fibres, abundant ground substance
56
Give examples of regular and irregular dense soft connective tissue.
Regular - tendon
Irregular - dermis
57
What is special about cartilage?
It is avascular and receives nutrients by diffusion through its matrix
58
What are the three types of cartilage?
Hyaline
Elastic
Fibrocartilage
59
Where is hyaline cartilage found?
Articular surfaces
Tracheal rings
Costal cartilage
Epiphyseal growth plates
60
What is the name given to the cell membrane of skeletal muscle?
Sarcolemma
61
What are the features of cardiac muscle?
Striated
Branching
Intercalated discs
62
What are glia?
Support cells of nervous tissue
63
How are neurons classified?
Bipolar
Unipolar
Multipolar
64
What are the functions of astrocytes?
Support
Ion transport
65
What is the function of oligodendrocytes?
Production of myelin
66
What is the function of microglia?
Immune surveillance
67
What do Schwann cells do?
Produce myelin and support axons
68
How can you tell the difference between serous secreting cells and mucus secreting cells histologically?
serous secreting cells stain intensely (purple)
mucus secreting cells stain very little (pink)
69
What type of glands are striated ducts a feature of?
Salivary glands
(the striated ducts modify the saliva by pumping salt out of the fluid)
70
What is the architecture of the digestive tract?
Mucosa - epithelium, lamina propria, muscularis mucosae
Submucosa
Muscularis externa
Serosa / Adventitia
71
Describe the muscularis externa of the digestive tract.
Two thick layers of smooth muscle:
Inner circular layer
Outer longitudinal layer
72
What is the function of the GI serosa/adventitia?
Suspends the GI tract, or attaches it to other organs
73
What type of epithelium lines the oral cavity, pharynx, oesophagus and anal canal?
What is its main function?
Non-keratinized stratified squamous epithelium
Protective
74
What type of epithelium lines the stomach?
What is its function?
Simple columnar epithelium with extensive tubular glands.
Secretory
75
What sort of epithelium lines the small intestine?
What is its function?
Simple columnar epithelium with tubular glands.
Absorptive
76
What type of epithelium lines the large intestine?
What is its function?
Simple columnar epithelium with tubular glands.
Protective and absorptive
77
What type of secreting cells do the gastric glands contain?
Chief cells - digestive enzymes
Parietal cells - hydrochloric acid
78
What is special about the outer, longitudinal muscle of the large intestine?
It is not continuous but found in 3 muscular strips
## Footnote
**teniae coli**
79
What is the enteric nervous system?
Nervous system belonging to the GI tract with about the same number of neurons as the spinal cord.
It receives input from the ANS, but is capable of coordinating gut motility locally
80
Where are the neurons of the enteric nervous sytem to be found?
In ganglia between the two layers of the muscularis externa
81
What is the architecture of the trachea?
Airway
Respiratory epithelium
Lamina propria
Submucosa with seromucous glands
Hyaline cartilage
82
Where does the production of urine begin?
Renal corpuscle - tuft of capillaries surrounded by epithelium
83
Which cells are the granulocytes?
Neutrophils
Basophils
Eosinophils
84
What are the three layers of muscular artery?
**Tunica intima**
internal elastic membrane
**Tunica media**
external elastic membrane
**Tunica adventitia**
85
What is the simple squamous epithelium of blood vessels referred to as?
Endothelium
86
What is the architecture of arterioles?
Only one or two layers of smooth muscles in the tunica media
Almost no adventitia
87
What is the architecture of capillaries?
Endothelial cells
Basal lamina
88
What is the vasa vasorum?
Vascular supply to large arteries
Needed because only the inner half of the wall can obtain nutrients from the lumen therefore they have their own blood supply
89
What are pericytes?
Cells found at intervals just outside the basal lamina of capillaries.
They are connective tissue cells with contractile properties
90
What are the three types of capillary?
**Continuous**
muscle, nerve, lung, skin
**Fenestrated**
gut mucosa, endocrine glands, kidney
**Sinusoidal**
liver, spleen, bone marrow
91
How is a venule differentiated from a capillary?
Once it begins to acquire intermittent smooth muscle cells in a tunica media
92
What is the architecture of veins?
Tunica intima
Thin but continuous tunica media
Obvious tunica adventitia
93
How are the valves of small and medium sized veins formed?
Inward extensions of the tunica intima
94
Why are mature red blood cells not true cells?
Because they have neither nucleus nor organelles
95
What is special about the shape of red blood cells?
They are deformable, allowing them to slip through small spaces.
96
What is the lifespan of a red blood cell?
About 4 months
97
Which is the most common type of leukocyte?
Neutrophils
98
What is the role of neutrophils?
Mobile phagocytes
99
How can eosinophils be recognised histologically?
Where do they tend to live?
They have an affinity for the red dye eosin.
They typically have a bilobed nucleus.
---
Tissue, particularly the spleen, lymph nodes and GI tract
100
How can basophils be recognised histologically?
They have an affinity for basic dye such as methylene blue
Their bilobed nucleus is often obscured by their granules
101
How can monocytes be recognised histologically?
Largest cells circulating in blood
Non-lobulated nucleus, often appears to have a kidney bean shape
102
Give three examples of resident macrophages.
Kupffer cells - liver
Microglia - brain
Langerhan's cells - skin
103
How can lymphocytes be distinguished histologically?
Round nucleus surrounded by moderate rim of cytoplasm with no visible granules
104
How can platelets be distinguished histologically?
They are much smaller than the other formed elements of blood
105
What are features of platelets?
Well developed cytoskeleton
Some organelles, but no nucleus
Conspicuous granules
106
What are the principle sites of blood formation in the embryo/foetus?
Yolk sac - around 3 weeks
Liver (spleen) - foetus
107
What is the main site of blood formation after birth?
Bone marrow
All bones participate at first
As they enlarge, limited to vertebra, ribs, skull, pelvis and proximal femurs
108
What is the main constituent of bone marrow in non-haemopoetic bones?
Adipose tissue
109
What is the architecture of bone?
Compact bone
Endosteum
Hemopoietic cells
Blood sinusoids
110
What does the term reticulocyte refer to?
The stage of development of a red blood before it loses its granules of RNA
111
What are megakaryocytes?
Giant cells found in bone marrow.
They undergo multiple duplications of nuclear material without undergoing nuclear or cell division.
Platelets are formed at the extensions of the outer margin.
After producing thousands of platelets, the megakaryocyte undergoes cell death by apoptosis.
