Connective Tissue Flashcards
CT are a diverse group of tissues that share common origin – the _______ of the embryo
mesenchyme
Specialized CT
Cartilage, Bone, Adipose tissues
CT consist of ____, _____, and ________ – relative abundance of these components are variable
cells, extracellular fibers and a ground substance
The CT are classified as:
- Embryonic CT – mesenchyme – mucous CT
- CT Proper – dense regular and irregular
- Specialized CT – adipose, blood, cartilage and bone
Functions of CT (5)
- bind together and support organ parenchyma
- maintain polarity of epithelial cells
- stabilize basal surface of epithelial cells
- organize cytoskeleton of epithelial cells
- help in metabolic functions of epithelial cells
__________ gives rise to other various CT of the body
Embryonic
________, the middle embryonic germ layer, gives rise to almost all kinds of CT in the body
Mesoderm
The primitive CT formed by mesoderm is called _________.
Mesenchyme
The _________ gives rise not only to the various CT of the adult but also to muscle, the vascular and urogenital systems, and the serous membranes of the body cavity hence sometimes called as ________ of all tissues
Mesenchyme; Mother cells
Embryonic CT is found in the _______ and within the _________.
Embryo; Umbilical cord
Embryonic CT is classified into two subtypes:
- Mesenchyme
- Mucous CT or Wharton’s jelly
Mesenchyme
primarily found in embryo and contains small spindle shape cells
Mucous CT or Wharton’s jelly
found in the umbilical cord
______________ consists of cells, fibers and matrix (ground substance) – the most abundant type of CT
The loose CT or Areolar CT or CT proper
The loose CT is primarily located ____________ that cover the body surfaces
Beneath epithelia
The loose CT are also associated with epithelia of _____ and ______________.
Glands and small blood vessels
The loose CT is the initial site where ____________ are challenged and destroyed by the immune system
pathogenic agents
____________ is characterized by randomly and irregularly arranged fibers and is found in _________________.
- Dense Irregular CT
- dermis, capsules of organs, sheath of tendons and nerves
_____________ is characterized by fibers precisely arranged in parallel array and is found in _______________________.
- Dense Regular CT
- tendons, ligaments, fascia, cornea, aponeurosis (a flat tissue connecting a muscle to a muscle or to a bone
CT fibers
- Collagen
- Reticular
- Elastic
__________ are found in all kinds of CT, are __________ (eosinophilic; stain _____ with H&E)
Collagen Fibers; Acidophilic; Pink
_______ are colorless without staining and slightly wavy in structure
Collagen Fibers
Each parallel fibril of collagen is called a ___________.
Collagen or Unit Fibril
The collagen or unit fibrils are polymers of ______________.
Collagen molecules
Each collagen molecule consists of _____________ known as ___________.
3 polypeptide chains; α chains
α chains are rich in ______ and two new unique amino acids, _________ and ________.
Glycine; hyroxyproline and hydroxylysine
Which fibrillar collagen is most ubiquitous (common), found in skin, bone, tendons, cornea
Type I
Which fibrillar collagen is found in hyaline and elastic cartilage
Type II
Which fibrillar collagen is traditionally reticular fibers, found in blood vessel walls, spleen, kidney, uterus]
Type III
Other classes of collagen (5)
- Fibril-associated collagens
- Hexagonal network-forming collagens
- Transmembrane collagens
- Multiplexins
- Basement membrane – forming collagens (Types IV, VI and VII)
Collagen is synthesized as ______ by _______ that are rich in rough endoplasmic reticulum
Procollagen; fibroblasts
_______ is exocytosed to extracellular matrix
Procollagen
Procollagen is converted to ______ by ______________.
Collagen; Procollagen peptidase
Collagen then polymerizes in extracellular space forming __________ by _________.
- collagen fibrils
- fibrillogenesis
Orientation of collagen fibers is either by ____________ of existing fibers or is _________ directed
Mechanical pressure; Fibroblast
Collagen fibers are degraded either by _______ or ________ pathway
proteolytic or phagocytic
Reticular fibers provide a __________ for the cellular constituents of various tissues and organs
supporting framework
Reticular fibers consists of _____ collagen fibrils
Type III
Reticular fibers are named so for their arrangement in a _______ pattern of network
meshlike
Reticular fibers are found surrounding…
adipose tissue, small blood vessels, nerves and muscle cells
Elastic fibers allow tissue to respond to ______ and _______.
stretch and distension
Elastic fibers are _______ than collagen fibers and arranged in a branching pattern
Thinner
Elastic fibers are _________.
Eosinophilic
Elastic property of elastin molecule is due to its ______________ that causes random coiling
unusual polypetide backbone
Elastic fibers are found in…
- loose CT
- walls of large arteries
- smooth muscles
- sarcolemma
- endoneurium
- glandular stroma
Elastic fibers appear _____ in color without staining
Yellow
Structural components of elastic fibers
Elastin and microfibrillin microfibrils
Elasin consists of _________ and is rich in ________ and two unique amino acids ______ and ______.
Nonpolar amino acids; Alanine; Desmosine and isodesmosine
Desmosine and isodesmosine are implicated in the development of a disease called ______.
lathyrism
In lathyrism the enzyme __________ is inhibited by substances such as ________________ resulting in an incomplete cross linking of collagen and elastic fibers
- Lysyl oxidase
- β – aminopropionitrile
Microfibrillin microfibrils made of _______ and ______.
Fibrillin-1 and Elastin
Fibrillin-1 is a glycoprotein with _________, less _____.
Polar amino acids; Glycine
Fibrillin -1 is deficient in patients with __________ , a heritable disorder, characterized by _____________ and a progressive ____________.
- Marfan Syndrome
- Excessively long arms and legs
- Dilatation of aorta
________ is a disease of poor communities in Central India, whose habitual staple food is the legume (pulse), Lathyrus sativus (kesari dal)
Lathyrism
The victims of the Lathyrism, usually young men, suffer irreversible __________ of their legs which incapacitate them for life
crippling paralysis
Lathyrism took its toll among poor _________ of Madhya Pradesh for nearly two centuries
agricultural laborers
The toxic factor which causes Lathyrism is _________.
BOAA (boxalyl amino alanine)
Collagen fiber components
Collagen with 3 polypeptide alpha chains
Collagen fiber amino acids
Rich in glycine and unique amino acids hydroxyproline and hydroxylysine
Collagen fiber disorders
Lathyrism
Collagen fiber types
I -VII important
Fibrillin fiber components
glycoprotein fibrillin
Fibrillin fiber disorders
Marfan Syndrome
Elastic fiber components
- Microfibrillar fibrillin
- Elastin
Elastic fiber amino acids
- Polar aa, less glycine
- Non-polar aa, rich in alanine and unique aa desmosine and isodesmosine
Elastic fiber disorders
Lathyrism
The ___________ is a complex structural network surrounding cells within the CT
extracellular matrix (ECM)
In addition to fibers the ECM contains a variety of…
- proteoglycans
- multiadhesive glycoproteins
- glycosaminglyccans (GAG)
GAG constitutes the __________.
Ground substance
ECM provides ____________ and also influences extracellular communications.
mechanical support
Cells are embedded in an ______________.
amorphous ground substance
The ground substance is a viscous, homogeneous, transparent and _____ gel.
PAS+
The ground substance is a _______ and consists of _________ units.
proteoglycan; glycosaminglycans (GAG) units
Common GAG include… (4)
- Chondroitin sulfate
- Keratan sulfate
- Heparan sulfate
- Hyaluronic acid – most abundant and is also found in joint fluid and vitreous humor of the eye
The Adhesions Glycoproteins called fibronectin, are involved in ___________, also found in ________, and synthesized by ______ and _________.
- Fibroblast adhesion
- Plasma
- Liver and Endothelium
The Adhesions Glycoproteins called laminin are found in ___________.
Basal lamina
The Adhesions Glycoproteins called Thrombospondin are synthesized by __________ and most abundant in __________.
- CT, endothelium, smooth muscle cells
- Granules of platelets
Adhesions Glycoproteins are involved in the interaction between ____ and ____.
Cells; ECM
Fixed cells
- Mensenchymal cells
- Fibroblasts and fibrocytes
- Adipose or fat cells
Mesenchymal cells
Embryonic tissue cells
Fibroblasts and fibrocytes
- Principal cells, most common
- Fusiform with several processes, eosinophilic cytoplasm, elliptical nucleus and rich in mitochondria
- Produce ECM
Adipose or fat cells
Store lipids, very little cytoplasm filled with fat droplets
Categories of macropages and where they originate from
- Fixed & Free
- Monocytes
Macrophages are identified and classified using _______ and _______.
Surface markers and secretory products
______ macrophages are within tissues, _______ are migratory from blood, and _______ are enhanced phagocytic activity.
- Resident
- Elicited
- Activated
In some pathological conditions macrophages assume a polygonal shape and are called ______ cells
Epithelioid
Some time macrophges make make ________ or ___________.
multinucleate masses or foreign body giant cells
Free Cells
- Mononuclear Phagocyte System or Reticulo-endothelial Cells
- Neutrophilic Leukocytes
- Eosinophilic Leukocytes
- Lymphocytes
- Mast Cells
- Plasma Cells
Mononuclear Phagocyte System or Reticulo-endothelial Cells include all ______ in tissues and are named as ______ in CT, Kupffer cells in liver, alveolar macrophages in lungs, and macrophages in brain
- Monocytes
- Histiocytes
Neutrophilic Leukocytes usually in ________ but gather in ______ during inflammation
- Circulation
- Tissues
Eosinophilic Leukocytes increase during _________, release ________, and in _________ infection 90% of leukocytes are eosinophils.
- Parasitic infections
- Antihistimines
- Schistosomiasis
Lymphocytes are the ______ of all free cells and increase during ___________.
- Smallest
- Inflammation
Mast cell and basophils arise from _________.
Same stem cells
Mast cells contain ________ nuclei and ______ cytoplasmic granules.
- Round or Oval
- Coarse
Mast cells have numerous ______ and are rich in _____ and ____.
- Villi
- ER and GC
Mast cells secrete
- Heparin (an anticoagulant)
- Histamine (a vasodilator)
- Proteases (tryptase and chymase)
- Eosinophil chemotactic factor
Plasma cells are _____ with _____ cytoplasm.
Ovoid; basophilic
Plasma cells have an ______ and ______ nucleus and are rich in _____ and _____.
- Eccentric and spherical
- RER and GC
Plasma cells principal production is ________ or ________ for humoral immunity.
antibodies or immunoglobulins (Ig)
Plasma cells are modified forms of ______.
B cell
Some plasma cells have glycoprotein inclusions called ________, which are accumulations of unused Ig chains
Russell Bodies
Serous membranes, a form of LCT, include _____, ______, and ______.
peritoneum, plurae and pericardium
Serous membranes are covered by layers of ________.
Mesothelium
In ________ (SM covering stomach) and _________ (SM covering intestines) mesothelium covers both surfaces.
- Omentum
- Mesentery
Spaces lined by serous membrane contain _______.
Fluids (peritoneal, plural or pericardial)
Free cells of SM include…
- Macrophages
- Mesothelial cells
- Small lymphocytes
- Eosinophils
- Mast cells
- Neutrophils
The ________ is a membrane that covers and protects most of the internal organs of the body. It is composed of two layers of cells, _____ and _____.
- Mesothelium
- Pleural and Parietal
_________ (cancer of the mesothelium) is a disease in which cells of the mesothelium become abnormal and divide without control or order.
Mesothelioma
Working with _______ is the major risk factor for mesothelioma.
Asbestos
Asbestos is the name of a group of _____ that occur naturally as masses of strong, flexible fibers that can be separated into thin threads and woven.
minerals
Normal functions of CT
- Mechanical support
- Exchange of metabolites
- Storage of energy in fat cells
- Protection against infection by leukocytes
- Repair after injury – called fibrogenesis
Role of CT in Inflammation
All blood cells in tissues involved
Glucocorticoids (hormone) _______ protein synthesis resulting in decreased _____.
Decreased; GAG
Sex hormones have dramatic effect in monkeys (less in humans) as they cause _______ protein synthesis resulting in increased ______.
Increase; GAG
Role of CT in Tissue Repair
Play important role in remodeling of bones
Disturbances of collagen metabolism are affected by _____ and _______.
age and nutrition
CT Diseases: Scurvy
vitamin C deficiency – inability to synthesize collagen
CT Diseases: Lathyrism
No cross-linking of fibers
______ is a form of CT specialized for fat storage.
Fat or Adipose Tissue
Fat or adipose tissue comprises ____ of body weight in males and _____ of body weight in females.
- 12-14%
- 25%+
Adipose tissue was long considered an _____ tissue, but it is in face a very _____ tissue.
Inert; Active
Fat cells or adipocytes actively synthesize _______ from ________ in diet.
Lipids from Carbohydrates
Fat cells are highly responsive to _______ and _____ stimulation.
- Hormonal
- Nervous
Two distinct types of adipose tissue
- White: widespread, bulk of body fat
- Brown: less abundant, limited to specific areas in humans, most common in hibernating animals
White (unilocular) AT makes up the _____ of body fat and is _____ to ________ (due to diet, carotinoids).
- Bulk
- White to Deep yellow
White (unilocular) AT cells are large _____ or ______ and a single droplet of _____.
- Polyhedral or spherical
- Oil
White (unilocular) AT appear ______ or _____ with Sudan Black stain.
Blank or black
Brown (multilocular) AT is present in ___________ and is ____ to _______ (due to cytochromes).
- Hibernating animals
- Tan to rich brown
Brown (multilocular) AT cells are relatively _____ and _____ and contain _____________.
- Small and Polygonal
- Multiple lipid droplets
Brown (multilocular) AT appear ______ or _____ with Sudan Black stain.
Blank or Black
Same as white AT
White (unilocular) AT has a ______ nucleus, _____ cytoplasm, and ______ number of mitochondria.
- Displaced
- Little ring of cytoplasm
- Average
Brown (multilocular) AT has a ______ nucleus, _____ cytoplasm, and ______ number of mitochondria.
- Central
- Abundant
- Extraordinary abundant
White (unilocular) AT Distribution
- Subcutaneous (Panniculus adiposus)
- Retroperitoneal areas
- Eye orbits
- Major joints
- Palms and soles
Brown (multilocular) AT Distribution
- Not in adults of all species
- Prominent in new born
- Abundant in hibernating animals
- In humans it decreases gradually and may reappear in elderly at the same location
Histogenesis: Prevailing view
Mesenchymal cells branch 3 ways
- Fibroblasts –> CT
- Fusiform lipoblasts –> UAT
- Round or oval lipoblasts –> MAT
In primary fat formation, _______ gather in gland like fashion, accumulate fat and form MAT.
Lipoblasts
Secondary fat formation is _______ AT formation. There is no _________ and _____ is formed.
- Postnatal
- No glandular fashion
- UAT
________ occurs in adults, increased lipid accumulation in same UAT, no increase in # of cells
Hypertrophic obesity
In ________ cells other than AT become AT, involves overfeeding during infancy
Hypercellular obesity
AT is metabolically _____; lipids are actively _______ and _______; half life in rate is 8 days & not known in humans.
- Active
- Mobilized
- Renewed
Fatty acids synthesized from glucose in diet and triacylglycerols synthesized from carbohydrates
Lipid Deposits
Enzyme hydrolysis – lipolysis through hormones and neurotransmitters
Lipid Withdrawals
Which hormones cause lipolysis through cAMP system?
Epinephrine, adrenocorticotropic, thyroid stimulating and luteinizing hormones
Which hormone causes lipogenesis by driving sugar into cells?
Insulin
Norepinephrine from nerve endings of the Autonomic Nervous System has an influence in that it increases _________.
Lipolysis
MAT is more abundant in ______.
hibernating animals
_________ organisms maintain temperature by vasodilation or vasoconstriction.
Homeothermic
In cold environment organisms exhibit _________.
shivering thermogenesis
Many organisms and human infants generate heat by _____________.
non-shivering thermogenesis
MAT is the site of _______________ (production of energy without muscle activity)
non-shivering thermogenesis
When hibernating animals begin to arouse ________ released from nervous system initiates ______________.
- norepinephrine
- lipolysis in MAT
MAT is the source of energy in _____ as shown by thermography
Bats
