Lab Quiz 2 Material (02/13/2025) + Ch. 6 (E3) Connective Tissue Flashcards
1
Q
In general, what 2 components make up connective tissue?
A
1) Cells
2) Tissue-specific extracellular matrix
2
Q
What 2 components comprise the extracellular matrix (ECM)?
A
1) Protein fibers
2) Ground substance (specialized molecules)
3
Q
The middle embryonic germ layer that gives rise to almost all of the connective tissues of the body.
A
What is the mesoderm?
4
Q
This “primitive connective tissue” is established in the early embryo through the proliferation and migration of the mesodermal and specific neural crest cells.
A
What is mesenchyme?
5
Q
Mesenchyme in the head region is sometimes referred to as…
A
Ectomesenchyme
6
Q
What are the 3 classifications of connective tissue?
A
1) Embryonic
2) Connective tissue proper
3) Specialized connective tissue
7
Q
List the 2 types of embryonic connective tissue.
A
1) Mesenchyme
2) Mucous connective tissue
8
Q
List the 2 types of connective tissue proper.
A
1) Loose connective
2) Dense connective
9
Q
List the 6 types of specialized connective tissue.
A
1) Cartilage
2) Bone
3) Blood
4) Adipose
5) Lymphatic
6) Hemopoietic
10
Q
This type of embryonic connective tissue is primarily found in the embryo and contains relatively uniform, small, spindle-shaped cells.
A
What is mesenchyme?
11
Q
This type of embryonic connective tissue is present in the umbilical cord and consists of a specialized, almost gelatin-like ECM composed mainly of hyaluronan.
A
What is mucous connective tissue?
12
Q
What is the ground substance of mucous connective tissue’s ECM frequently referred to as?
A
Wharton jelly
13
Q
Loose connective tissue is sometimes called {…} tissue.
A
Areolar
14
Q
What are the 2 subtypes of dense connective tissue?
A
1) Dense regular
2) Dense irregular
15
Q
What 2 things characterize loose connective tissue?
A
1) Loosely arranged fibers
2) Various abundant cell types
16
Q
Where is loose connective tissue primarily located?
A
Beneath the epithelia that cover the body surfaces and line the internal surfaces of the body
17
Q
Most cell types in loose connective tissue are transient wandering cells that migrate from local blood vessels in response to specific stimuli. As such, loose connective tissue is the site of these two bodily reactions.
A
What are inflammatory and immune reactions?
18
Q
The term for the loose connective tissue of the mucous membranes, such as those of the respiratory and alimentary systems, which contain large numbers of immune cells.
A
What is the lamina propria?
19
Q
How is dense irregular connective tissue characterized? List 2 specific details.
A
1) Abundant fibers
2) Few cells
20
Q
The relatively thick layer of dense irregular connective tissue found within the dermis is referred to as this.
A
What is the reticular (deep) layer?
21
Q
Hollow organs (e.g., the intestinal tract) possess a distinct layer of dense irregular connective tissue called the {…} in which the fiber bundles course in varying planes.
A
Submucosa
22
Q
Why is it important for the fiber bundles of the submucosa to run along various planes?
A
To allow organs to resist extensive stretching and distension
23
Q
How is dense regular connective tissue characterized?
A
Orderly and densely packed arrays of fibers and cells
24
Q
In what way is dense regular and irregular connective tissue similar?
A
They both contain little ground substance
25
How are the fibers in dense regular connective tissue arranged? Why are they arranged this way?
The fibers are arranged in a parallel array and are densely packed to provide maximum strength
26
Dense regular connective tissue is the main functional component of these 3 connective structures.
What are tendons, ligaments, and aponeuroses?
27
Cord-like structures that attach muscle to bone.
What are tendons?
28
What is the name of the fibroblasts that are situated between the parallel bundles of collagen fibers within tendons?
Tendinocytes
29
The substance of the tendon surrounded by a thin connective tissue capsule is called this.
What is epitendineum?
30
The connective tissue extension of the epitendineum subdivides the tendon into fascicles.
What is endotendineum?
31
Where will you find small blood vessels and nerves of the tendon? In the epitendineum or the endotendineum?
Endotendineum
32
The dense, regular connective tissue structures that connect bone to bone and whose fibers are less regularly arranged than tendons.
What are ligaments?
33
This type of ligament contains more elastic fibers than collagen fibers.
What is an elastic ligament?
34
This sheet of dense regular connective tissue resembles a broad, flattened tendon.
What is an aponeurosis?
35
In an aponeurosis, the collagen fibers in one layer tend to be arranged at a 90-degree angle to those of neighboring layers. What is this type of organization called?
An orthogonal array
36
In what other structure will you find an orthogonal array?
Cornea
37
What does the orthogonal array do for the cornea?
It's responsible for the cornea's transparency
38
What are the 3 types of connective tissue fibers?
1) Collagen
2) Elastic
3) Reticular
39
These fibers are the most abundant structural components of connective tissue.
What are collagen fibers?
40
These are the fine, thread-like subunits that appear as bundles to form collagen fibers.
What are collagen fibrils?
41
An old term for collagen molecule.
What is tropocollagen?
42
What is the length of the collagen fibril banding pattern?
68-nm
43
A single collagen molecule consists of 3 polypeptides known as these.
What are α-chains?
44
Every {...} (numerical position) amino acid in the chain is a {...} molecule, except at the ends of the α-chains. A {...} or {...} frequently precedes each glycine in the chain, and a {...} frequently follows each glycine in the chain.
1) 3rd
2) Glycine
3) Hydroxyproline
4) Hydroxylysine
5) Proline
45
Associated with the helix are sugar groups that are joined to hydroxylysyl residues. Because of these sugar groups, collagen is properly described as a...
NOTE: protein + sugar = ...
Glycoprotein
46
A collagen molecule consisting of three identical α-chains is considered...
Homotrimeric
47
A collagen molecule consisting of 2 or even 3 genetically distinct α-chains is considered...
Heterotrimeric
48
This type of collagen found in loose and dense connective tissue is heterotrimeric.
What is Type I collagen?
49
This type of collagen is homotrimeric and present in hyaline & elastic cartilage, where it occurs as very fine fibrils.
What is Type II collagen?
50
These collagens include types I, II, III, V, and XI collagen molecules. Additionally, they are characterized by uninterrupted glycine–proline–hydroxyproline repeats and aggregate to form 68-nm-banded fibrils.
What are fibrillar collagens?
51
These collagens have interruptions in their triple helices that provide flexibility to the molecule.
What are fibril-associated collagens w/ interrupted triple helices?
52
These collagens are represented by collagen types VIII and X.
What are hexagonal network-forming collagens?
53
These collagens are represented by types XIII (found in focal adhesions), XVII (found within hemidesmosomes), XXIII (found in metastatic cancer cells), and XXV (a brain-specific collagen).
What are transmembrane collagens?
54
These collagens are collagens with with multiple triple-helix domains and interruptions. They comprise collagen types XV and XVIII, which reside in the basement membrane zones.
What are multiplexins?
55
These collagens include type IV collagen, which is responsible for the collagen suprastructure in the basement membrane of epithelial cells; type VI collagen, which forms beaded filaments; type VII collagen, which forms anchoring fibrils that attach the basement membrane to the ECM; and type XXVIII collagen, which, in peripheral nerves, plays a role in the assembly of basement membranes of supporting cells.
What are basement membrane-forming collagens?
56
The production of fibrillar collagen (I, II, III, V, and XI) involves a series of events within the fibroblast that leads to the production of {...}, the precursor of the collagen molecule.
Procollagen
57
Process in which aggregated collagen molecules align to form the final collagen fibrils.
What is fibrillogenesis?
58
The cell simultaneously creates specialized collagen assembly sites called these.
What are coves?
59
True or False: Collagen fibrils often consist of one or more types of collagen.
True
60
List the 2 pathways in which collagen fibers are degraded.
1) Proteolytic
2) Phagocytic
61
In what 2 bone diseases is excessive collagen degradation observed?
Rheumatoid arthritis & osteoporosis
62
This type of collagen degradation occurs outside the cells through the activity of enzymes called matrix metalloproteinases (MMPs).
What is proteolytic degradation?
63
This type of collagen degradation occurs intracellularly and involves macrophages to remove components of the ECM.
What is phagocytic degradation?
64
What is the role of matrix metalloproteinases (MMPs) in cancer metastasis? What inhibitors can be used to halt metastasis?
Invasive (migrating/metastasizing) cancer cells secrete MMPs, which are linked to the pervasiveness of metastasis; tissue inhibitors of metalloproteinases (TIMPs) could control metastasis
65
Unlike collagen fibers, reticular fibers are composed mainly of this type of collagen.
What is Type III?
66
Reticular fibers are readily displayed by means of the {...} (PAS) reaction. They are also revealed with special silver-staining procedures, such as the Gomori and Wilder methods. After silver treatment, the fibers appear black; thus, they are said to be {...}.
1) Periodic acid-Schiff
2) Argyrophilic
67
These diseases are caused by a deficit or abnormality in the production of specific collagens.
What are collagenopathies?
68
Mutations in these genes are responsible for osteogenesis imperfecta.
What are COL1A1 & COL1A2?
69
Osteogenesis imperfecta results from a mutation in this type of collagen.
What is Type I?
70
Hypermobile Ehler-Danlos and the vascular variant are caused by mutations of these collagen types specifically.
What are Types III & IV?
71
Classic Ehlers-Danlos syndrome is caused by a mutation in this type of collagen.
What is Type V?
72
What are reticular fibers named for?
Their arrangement in a mesh-like pattern/network
73
These fibers are typically thinner than collagen fibers and are arranged in a branching pattern to form a three-dimensional network.
What are elastic fibers?
74
For what purpose do elastic fibers serve tissues?
To allow tissue to respond to stretch and distension
75
How much more flexible is elastin than collagen?
1000x
76
What cells produce the reticular fibers in lymphatic and hemopoietic tissues? How is this different than the cells that produce reticular fibers in other cells?
Lymphatic & hemopoietic tissues - specialized reticular cells
Fibroblasts produce reticular fibers in most other tissues
77
Where in the body will you find a lot of elastic material? List 3 places.
1) Vertebral ligaments (e.g., ligamenta flava & ligamentum nuchae)
2) Larynx (e.g., vocal folds)
3) Elastic arteries
78
This is one of the most hydrophobic proteins in the body.
What is elastin?
79
What is responsible for the random coiling of elastin?
The unusual polypeptide backbone, which consists of many nonpolar amino acids
80
Elastin also contains {...} and {...}, two large amino acids unique to elastin, which are also responsible for the covalent bonding of elastin molecules to one another.
1) Desmosine
2) Isodesmosine
81
This is one of the largest genes in the human genome; it encodes elastin.
What is the elastin (ELN) gene?
82
In {...} (SVAS), mutated elastin forms thinner elastic fibers and disorganized elastic lamellae in the wall of the ascending aorta. This triggers a compensation reaction in which increased production and deposition of smooth muscle in the aortic wall thickens the artery wall and progressively narrows the lumen.
Supravascular aortic stenosis
83
A mutation in the ELN gene is an inherited or acquired disease characterized by wrinkled, redundant, sagging, and inelastic skin caused by defective dermal elastic fibers synthesis.
What is cutis laxa?
84
Fibrillin-1 (350 kDa) is a glycoprotein that polymerizes in the extracellular space in a head-to-tail arrangement to form these fine, cable-like structures measuring 10-12 nm in diameter.
What are fibrillin microfibrils?
85
These fibers are produced by fibroblasts, chondrocytes, endothelial cells, and smooth muscle cells. They allow for stretching and distension.
What are elastic fibers?
86
Elastic fibers are composed of cross-linked {...} molecules associated with a network of {...} microfibrils, which are made of fibrillin and fibrillin-associated proteins (e.g., EMILINs & MAGPs).
1) Elastin
2) Fibrillin
87
Prolonged exposure to UV radiation that causes chronological aging of the skin is referred to as this.
What is photoaging?
88
How does photoaged skin differ from normally chronologically aged skin in terms of the overall number of elastic fibers?
Normally aged skin loses elastic fibers over time, but photoaged skin shows an increase in abnormally thick, non-functional elastic fibers (as well as a noticeable decrease in the fibrillin microfibrils that allow for elasticity). As such, photoaged skin is rather stiff
89
What 3 groups of molecules constitute the ground substance in connective tissue? Of these 3 groups, which group is responsible for the physical properties of ground substance?
1) Proteoglycans
2) Glycosaminoglycans - PHYSICAL PROPERTIES
3) Multiadhesive glycoproteins
90
This glycosaminoglycan (GAG) is always present in the ECM as a free carbohydrate chain. It is also the largest and longest GAG.
What is hyaluronan (hyaluronic acid)?
91
Where will you find ground substance?
In the ECM
92
How does the chemical structure of hyaluronan differ from other GAGs?
Hyaluronan does not contain sulfate groups
93
Why is hyaluronan always present in the form of a free carb chain?
It isn't covalently bound to protein, so it cannot form proteoglycans
94
How can proteglycans indirectly bind to hyaluronan to form proteoglycan aggregates?
Via special linker proteins
95
What are 2 key functions of hyaluronan?
1) Resist compression w/o sacrificing flexibility (i.e., shock absorption)
2) Immobilizing certain molecules in the desired location of the ECM
96
The majority of GAGs in the connective tissue are linked to core proteins, forming {...}.
Proteoglycans
97
These proteins play an important role in stabilizing the ECM and linking it to cell surfaces. Additionally, they represent a small but important group of proteins residing in the ECM.
What are multiadhesive glycoproteins?
98
The most abundant multiadhesive glycoprotein.
What is fibronectin?
99
This multiadhesive glycoprotein appears during embryogenesis, but its synthesis is switched off in mature tissues.
What is tenascin?
100
This multiadhesive glycoprotein is present in basal and external laminae.
What is laminin?
101
This multiadhesive glycoprotein is present in the ECM of bone.
What is osteopontin?
102
The cells that make up the {...} cell population are relatively stable; they typically exhibit little movement and can be regarded as permanent residents of the tissue.
Resident
103
Fibroblasts, myofibroblasts, macrophages, adipocytes, mast cells, & adult stem cells make up this connective tissue cell population.
What is resident?
104
The {...} cell population consists primarily of cells that have migrated into the tissue from the blood in response to specific stimuli.
Wandering/transient
105
Lymphocytes, plasma cells, neutrophils, eosinophils, basophils, & monocytes make up this connective tissue cell population.
What is wander/transient?
106
This is the principle cell of connective tissue and is responsible for the synthesis of collagen, elastic, and reticular fibers and the complex carbohydrates of the ground substance.
What is the fibroblast?
107
An elongated, spindly connective tissue cell not readily identifiable in routine H&E preparations. It is characterized by the presence of bundles of actin filaments with associated actin motor proteins such as non-muscle myosin.
What is the myofibroblast?
108
The myofibroblast displays properties of both {...} and {...} muscle cells.
1) Fibroblasts
2) Smooth
109
The arrangement of actin bundles and their attachment sites form a {...} system, in which forces generated by the contraction of intracellular actin bundles are transmitted to the ECM.
Mechano-transduction
110
In what way are myofibroblasts characteristically similar to smooth muscle cells?
NOTE: Actin filaments & density
They contain bundles of longitudinally disposed actin filaments and dense bodies
111
Connective tissue macrophages, also known as tissue {...}, are derived from blood cells called {...}.
1) Histiocytes
2) Monocytes
112
What organelle would you expect to be particularly abundant in a macrophage based on the macrophage's function?
Lysosomes
113
Regulated secretion can be activated by phagocytosis, immune complexes, complement, and signals from lymphocytes (including the release of {...}, biologically active molecules that influence the activity of other cells).
Lymphokines
114
Macrophages are {...} cells and play an important role in {...} response reactions.
1) Antigen-presenting
2) Immune
115
Macrophages have specific proteins on their surface known as {...} (MHC II) molecules that allow them to interact with helper CD4+ T lymphocytes.
Major histocompatibility complex II
116
Why are macrophages known as antigen-presenting cells (APCs)?
They present antigens to helper CD4+ T lymphocytes
117
When and where do macrophages arrive?
After neutrophils and at the site of tissue injury
118
Interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), or by bacterial lipopolysaccharide (LPS) create this type of macrophage.
What is the classically-activated (M1) macrophage?
119
What 2 reactions do M1 macrophages elicit?
1) Chronic inflammation
2) Tissue injury
120
When macrophages encounter large foreign bodies, they may fuse to form a large cell with as many as 100 nuclei that engulfs the foreign body. These multinucleated cells are called...
Foreign-body giant (Langhan) cells
121
These macrophages assist in the resolution of inflammation and promote rebuilding of ECM, cell proliferation, and angiogenesis.
What are alternatively activated (M2) macrophages?
122
In addition to their beneficial activities, M2 macrophages are involved in pathogenesis of {...} and {...}.
1) Allergy
2) Asthma
123
These cells develop in the bone marrow and differentiate into connective tissue. They have a spherical nucleus and cytoplasm filled with large, intensely basophilic granules.
What are mast cells?
124
These progenitor cells initially circulate in the peripheral blood as agranular cells of monocytic appearance. After migrating into the connective tissue, these immature cells differentiate and produce their characteristic granules.
What are mast cell progenitors (MCPs)?
125
These progenitor cells differentiate and remain within the circulatory system.
What are basophil progenitors (BaPs)?
126
Although the {...} (sheets of connective tissue that surround the brain and spinal cord) contain mast cells, the connective tissue around the small blood vessels within the brain and spinal cord is {...} of mast cells.
1) Meninges
2) Devoid
127
Mast cells contain intensely basophilic granules that store chemical substances known as these mediators.
What are mediators of inflammation?
128
This class of inflammation mediator produced by mast cells is stored in secretory granules and released upon cell activation.
What is a preformed mediator?
129
This class of inflammation mediator produced by mast cells is often absent in the resting cells, although they are produced and secreted by activated mast cells.
What are newly synthesized mediators?
130
List the 4 main preformed mediators.
1) Histamine
2) Heparin
3) Serine proteases
4) Esosinophil & neutrophil chemotactic factor
131
List the 3 main newly synthesized mediators.
1) Leukotriene C, D, E
2) TNF-alpha
3) Many interleukins
132
The leukotriene receptor antagonists are among the most prescribed drugs for the management of this respiratory disorder.
What is asthma?
133
These are granulocytes that circulate in the bloodstream and comprise less than 1% of peripheral white blood cells (leukocytes).
What are basophils?
134
Why do basophils share many features in common with mast cells?
They share a common precursor cell in the bone marrow
135
These cells differentiate from mesenchymal stem cells and gradually accumulate fat in their cytoplasm. They are located throughout loose connective tissue as individual cells and groups of cells.
What are adipocytes?
136
What 2 things to adipocytes store?
1) Neutral fat
2) Hormones
137
The stem cells found in many tissues of mature individuals.
What are adult stem cells?
138
Adult stem cells are found in many tissues and organs, residing in specific sites referred to as...
Niches
139
Cells residing within niches in various tissues and organs (excluding the bone marrow) are called {...} stem cells.
Tissue
140
Niches of adult stem cells, called {...} stem cells, are found in the loose connective tissue of adults. These cells give rise to differentiated cells that function in the repair and formation of new tissue, such as in wound healing and the development of new blood vessels (neovascularization).
Mesenchymal
141
These cells are typically wrapped, at least partially, around capillaries & venules and have a role as mesenchymal stem cells.
What are pericytes (adventitial/perivascular cells)?
142
These are the smallest wandering cells in the connective tissue.
What are lymphocytes?
143
These lymphocytes have a long lifespan and are effectors in cell-mediated immunity. Additionally, they migrate from the bone marrow to the thymus to mature.
What are T lymphocytes?
144
These lymphocytes recognize antigens, have a variable lifespan, and are effectors in antibody-mediated (humoral) immunity. Additionally, they mature in the bone marrow.
What are B lymphocytes?
145
These lymphocytes are non-T, non-B lymphocytes that are not antigen specific. Similar in action to T lymphocytes, however, they destroy virus-infected cells and some tumor cells by a cytotoxic mechanism.
What are natural-killer (NK) lymphocytes?
146
These are antibody-producing cells derived from B lymphocytes.
What are plasma cells?
147
What is the lifespan of plasma cells, and what is their function?
10-30 days; they have limited migratory ability
148
Are plasma cells antigen-specific? Why?
Yes b/c they produce large amounts of only 1 protein
149
What are the 2 functions of the eosinophil?
1) Allergic reaction
2) Responding to parasitic infections
