1.03 - Connective Tissue Flashcards Preview

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Flashcards in 1.03 - Connective Tissue Deck (35):
1

Define: Tissue

A group of similar cells specialised in a particular way for the performance of a common function

2

Define: Connective Tissue

Supports the various organs and fills the spaces between different tissue types. Binds tissue systems together.

3

What does connective tissue do?

Structural (binds together, protects and support other tissues)
Mediate exchange of nutrients, metabolites and waste products between cells and the circulatory system
Repair
Defence

4

What two components form connective tissue?

Extracellular matrix (made up of ground substance & fibres)
Cells: Indigenous (fibroblasts, adipocytes & reticulocytes) & Migratory (cells of the immune system)

5

What are the two different types of connective tissue in the body and their respective subtypes?

Connective tissue proper
Special: vascular connective tissue, cartilage, bone

6

What are the types of indigenous cells that form part of connective tissue?

Fibroblasts
Reticulocytes
Adipocytes

7

Describe Fibroblasts

The active form of the cell
Responsible for maintenance and synthesis of extracellular matrix
Contain large amounts of organelles
Easily found in healing wounds

8

What is a Fibrocyte and how is it different to a Fibroblast?

Fibrocytes are the mature inactive form of fibroblasts. They are larger than fibroblasts and their nuclei typically stains lighter
They also have irregular cytoplasms

9

Describe Adipocytes

Adapted for storage of fat
Immature form in known as lipoblast
Very long lived cells
Large in size due to fat accumulation
Nucleus pushed to periphery

10

Describe the differences between White Adipose and Brown Adipose Tissue

White: 20-25% of total body weight in humans. Important for energy storage. Thermal insulator. Cushion against mechanical shock for deep organs.
Brown: Typically found in newborns. Temperature regulation

11

Name the Migratory cells of the immune system

Macrophages
Mast Cells
Plasma Cells
Eosinophils
Lymphocytes

12

Describe Macrophages

Precursor: monocytes
Originate in bone marrow and enter blood stream. Enter tissue and differentiate into macrophages
Life span: months to years
Main function is defence: act as tissue scavengers as they phagocytose foreign materials
Antigen presenting cell to lymphocytes and other cells

13

Describe Mast Cells

Derived from basophils in the bone marrow
Migrate to peripheral tissues such as the skin and GIT and develop and differentiate.
Cytoplasm filled with numerous large vesicles
Present in healthy connective tissue - they stand guard and monitor local situation
Function: defence against protein containing foreign material like bacterium or allergens
Discharge contents of vesicles (heparin and histamine) on contact which causes capillaries to leak, vasodilation and improve blood flow to the area

14

Describe plasma cells

main function: defence
Produce antibodies. cytoplasm increases when producing antibodies

15

Describe Eosinophils

Originate in bone marrow
Rounded or oval cells with a bilobed nucleus
Contain large amounts of bright red granules in the cytoplasm.
Found in healthy connective tissue
8-12 day life span
Main Function: Defence against parasites and in some allergic disorders - either phagocytose or release their granule content

16

Describe Lymphocytes

Derived from the bone marrow
Circulate in blood between various lymphoid tissues in various amounts
Their nuclei are round and stain very dark. The cytoplasm forms a narrow rim around the nucleus and may be difficult to see.

17

What are the three subtypes of fibre that make up the extracellular matrix?

Collagen
Elastin
Reticular

18

Describe Collagen Fibres

Dominant type seen on most connective tissues
Main function: Strength & Support
Elongated and arranged in a regular manner
Forms capsules of several organs (liver, spleen, kidney)
Wavy, pink appearance in H&E stain
Composed of thinner collagen fibrils which is composed of microfibrils.

19

What are the types of collagen fibres?

Type I
Type II
Type III
Type IV
Type V

20

Describe the location and cells of origin of Type 1 Collagen

Found in Loose & Dense ordinary connective tissue as well as bone.
Produced by fibroblasts and osteoblasts

21

Describe Reticular Fibres

Collagen Type III
Tiny collagen fibres
Form delicate networks instead of thick bundles
Main function: supporting framework for cells in organs like the liver, lymph node and adrenals

22

Describe Elastic Fibres

Elastin molecules are cross-linked to each other and form a random coil
Can be stretched to 150% of their original length
Can resist severe chemical conditions (extreme of alkalinity, acidity and heat that destroys collage)
Main Function: Confer elasticity
Found in the skin, blood vessels, lung, urinary bladder, ligaments and cartilage
Consists of individual microfibrils, which are embedded in an amorphous matrix
Produced by fibroblasts and smooth muscle cells

23

Describe Ground Substance

Semi-fluid gel-like material composed of: glycoaminoglycan, proteoglycans, glycoproteins
Main Function: act as a medium for passage of molecules and exchange of metabolites.
Functions: contributes to physical consistency, an adhesive substance for collagen fibres, transport and regulation of water and electrolytes, barrier to spread of bacteria, absorb compressive loads

24

Describe the basement membrane

Sheet of extracellular matrix proteins between epithelial cells and the parenchyma
Functions:
Provides structural support
Involved in control of growth of epithelial cells
Permits the passage of nutrients and metabolites
May regulate permeability (kidney)

25

What are the types of connective tissue?

Dense
Loose (Mucoid, Reticular, Adipose)

26

Describe Dense Connective Tissue

Lots more fibres, less cells, less ground substance
Divided into two subcategories based on the spatial arrangement of the fibres: Regular and Irregular

27

Describe Irregular Dense Connective Tissue

Densely woven 3D network that resists deformation. Moderately packed thick fibre bundles arranged in a meshwork. Fibrocytes scattered amongst fibres.
Examples: Dermis layer of the skin, capsule sheaths around organs

28

Describe Regular Dense Connective Tissue

Tightly packed bundle fibres run parallel to each other - stress only in one direction so fibres are arranged to resist deformation in that direction
Fibrocytes squeezed in-between fibre bundles
Examples: tendons, ligaments, cornea of the eye

29

Describe Loose Connective Tissue

Permits mobility between structures.
Present in all parts of the body
Also called areolar connective tissue
Special Variants: Mucoid, Reticular, Adipose

30

Describe Mucoid Connective Tissue

More space between the cells
Large amount of ground substance leading to decreased cohesiveness
Examples: umbilical cord, dental pulp

31

Descrive Reticular Connective Tissue

Consists of reticular cells and the network of fibres formed by them.
Forms the structural framework in which the cells of the organ are suspended
Useful in tissues and organs in which diffusion and or cell movements are functionally important
Examples: liver, lymph nodes, spleen

32

Describe Adipose Tissue

Connective tissue containing large number of adipocytes
Two types: Brown & White

33

Describe White Adipose Tissue

Unilocular adipose tissue containing one large lipid droplet
Functions: storage of lipids, structural, cushioning (palms of hand, soles of feet, gluteal region

34

Describe Brown Adipose Tissue

Multilocular Adipose Tissue containing many lipid droplets
Functions: fetal development, cells generate heat by decoupling of oxidation of fatty acids.
Most brown differentiates into white fat in adults
Contain large number of mitochondria
Located in axilla, between shoulder blades, neck region and around large blood vessels

35

1. The constituent of extracellular matrix largely responsible for providing strength and support to connective tissues is:
a. Brown fat
b. Collagen
c. Elastin
d. Ground substance
e. White fat

Collagen