Connective tissues are the most diverse and abundant tissues in the body. They include connective tissue proper, blood, cartilage, and bone. Connective tissues are composed of cells embedded in an extracellular matrix containing fibers and ground substance. They serve important functions such as binding and supporting other tissues, holding body fluids, defending the body, and storing nutrients. The main classes of connective tissue proper are loose connective tissues like areolar and adipose tissue, and dense regular and irregular connective tissues.

1. Connective Tissues

2. Connective Tissue
 Most diverse and abundant tissue
 Main classes
 Connective tissue proper
 Blood – Fluid connective tissue
 Cartilage
 Bone tissue
 Components of connective tissue:
 Cells (varies according to tissue)
 Matrix
 Protein fibers (varies according to tissue)
 Ground substance (varies according to tissue)
 Common embryonic origin – mesenchyme
Supporting connective tissues

3. Connective Tissues

5. Classes of Connective Tissue

6. Connective Tissue
 Originate from embryonic tissue called
mesenchyme
 Most diverse and abundant type of tissue
 Many subclasses (see previous slide)
 Function: to protect, support and bind together
other tissues
 Bones, ligaments, tendons
 Areolar cushions; adipose insulates and is food
source
 Blood cells replenished; body tissues repaired
 Cells separated from one another by large
amount of nonliving extracellular matrix

8. Extracellular Matrix explained
 Nonliving material between cells
 Produced by the cells and then extruded
 Responsible for the strength
 Two components
1. Ground substance
 Of fluid, adhesion proteins, proteoglycans
 Liquid, semisolid, gel-like or very hard
2. Fibers: collagen, elastic or reticular

9. Basic functions of connective tissue
reviewed
 Support and binding of other tissues
 Holding body fluids
 Defending the body against infection
macrophages, plasma cells, mast cells, WBCs
 Storing nutrients as fat

10. Mast cells: partial list of important molecules
released from these granules includes
 Heparin, a sulfated
glycosaminoglycan that
acts locally as an
anticoagulant
 Histamine, which
promotes increased
vascular permeability and
smooth muscle
contraction
 Serine proteases, which
activate various mediators of
inflammation
 Eosinophil&neutrophil chemotactic
factors which attract those leukocytes
 Leukotrienes C4, D4,
and E4 (or the slow-reacting
substance of anaphylaxis, SRS-A)
which also trigger smooth muscle
contraction.

11. Classes of Connective Tissue
*

14. Two general classes of connective tissue proper:
loose dense

15. Dense Connective tissue
Irregular Regular

22. *
Classes of Connective Tissue

24. Hyaline cartilage and perichondrium.

28. Classes of Connective Tissue
*

30. BONE CELLS

32. TYPES OF
BONE

35. Cells and matrices of a primary
ossification center

36. Main features of bone fracture repair.

37. Joints

38. Classes of Connective Tissue
*

39. Blood and its component

40. Blood smear preparation

41. Red blood cell: Erythrocytes

43. White Blood cell: Leukocytes

44. Membranes that combine epithelial
sheets plus underlying connective tissue
proper (see next slide)
 Cutaneous membranes
 Skin: epidermis and dermis
 Mucous membranes, or mucosa
 Lines every hollow internal organ that opens to the
outside of the body
 Serous membranes, or serosa
 Slippery membranes lining the pleural, pericardial and
peritoneal cavities
 The fluid formed on the surfaces is called a transudate
 Synovial membranes
 Line joints

45. (a) Cutaneous membrane
(b) Mucous membrane
(c) Serous membrane

46. Connective Tissue Proper - Structures
 Variety of cells, fibers & grounds substances
 Types of depend on use
 Cells found in connective tissue proper
 Fibroblasts
 Macrophages, lymphocytes (antibody producing cells)
 Adipocytes (fat cells)
 Mast cells
 Stem cells
 Fibers:
 Collagen – very strong & abundant, long & straight
 Elastic – branching fibers with a wavy appearance (when
relaxed)
 Reticular – form a network of fibers that form a supportive
framwork in soft organs (i.e. Spleen & liver)
 Ground substance:
 Along with fibers, fills the extracellular space
 Ground substance helps determine functionality of tissue

47. Connective Tissue Proper -
Classifications
 Loose Connective Tissue
 Areolar
 Reticular
 Adipose
 Dense Connective Tissue
 Regular
 Irregular
 Elastic

48. Areolar Connective Tissue
 Description
 Gel-like matrix with:
 all three fiber types (collagen, reticular, elastic) for support
 Ground substance is made up by glycoproteins also made
and secreted by the fibroblasts.
 Cells – fibroblasts, macrophages, mast cells, white
blood cells, adipocytes
 Highly vascular tissue
 Function
 Wraps and cushions organs
 Holds and conveys tissue fluid
 Important role in inflammation
 Main battlefield in fight against infection

49. Areolar Connective Tissue
 Location
Widely distributed under epithelia
Packages organs
Surrounds capillaries

50. Adipose Tissue
 Description
 Closely packed adipocytes
 Have nucleus pushed to one
side by fat droplet Function
 Provides reserve food fuel
 Insulates against heat loss
 Supports and protects organs
 Location
 Under skin
 Around kidneys
 Behind eyeballs, within
abdomen and in breasts

51. Reticular Connective Tissue
 Description – network of
reticular fibers in loose
ground substance
 Function – form a
soft, internal skeleton
(stroma) – supports other
cell types
 Location – lymphoid
organs
 Lymph nodes, bone
marrow, and spleen

52. Dense Irregular Connective Tissue
 Description
 Primarily irregularly arranged
collagen fibers
 Some elastic fibers and
fibroblasts
 Function
 Withstands tension
 Provides structural strength
 Location
 Dermis of skin
 Submucosa of digestive tract
 Fibrous capsules of joints
and organs

53. Dense Regular Connective Tissue
 Description
 Primarily parallel collagen fibers
 Fibroblasts and some elastic fibers
 Poorly vascularized
 Function
 Attaches muscle to bone
 Attaches bone to bone
 Withstands great stress in
one direction
 Location
 Tendons and ligaments
 Aponeuroses
 Fascia around muscles

54. Cartilage
 Characteristics:
 Firm, flexible tissue
 Contains no blood vessels or
nerves
 Matrix contains up to 80%
water
 Cell type – chondrocyte
 Types:
 Hyaline
 Elastic
 Fibrocartilage

55. Hyaline Cartilage
 Description
 Imperceptible collagen fibers (hyaline = glassy)
 Chodroblasts produce matrix
 Chondrocytes lie in lacunae
 Function
 Supports and reinforces
 Resilient cushion
 Resists repetitive stress
 Location
 Ends of long bones
 Costal cartilage of ribs
 Cartilages of nose,
trachea, and larynx Location

56. Elastic Cartilage
 Description
 Similar to hyaline cartilage
 More elastic fibers in matrix
 Function
 Maintains shape of structure
 Allows great flexibility
 Location
 Supports external ear
 Epiglottis

57. Fibrocartilage
 Description
 Matrix similar, but less firm
than hyaline cartilage
 Thick collagen fibers
predominate
 Function
 Tensile strength and ability
to absorb compressive
shock
 Location
 Intervertebral discs
 Pubic symphysis
 Discs of knee joint

58. Bone Tissue
 Function
 Supports and protects
organs
 Provides levers and
attachment site for
muscles
 Stores calcium and
other minerals
 Stores fat
 Marrow is site for blood
cell formation
 Location
 Bones

59. Blood Tissue
 Description
 red and white blood cells
in a fluid matrix
 Function
 transport of respiratory
gases, nutrients, and wastes
 Location
 within blood vessels
 Characteristics
 An atypical connective tissue
 Consists of cells surrounded by fluid matrix

60. Covering and Lining Membranes
 Combine epithelial tissues and connective
tissues
 Cover broad areas within body
 Consist of epithelial sheet plus underlying
connective tissue

61. Types of Membranes
 Cutaneous membrane – skin
 Mucous membrane
 Lines hollow organs that open to surface of body
 An epithelial sheet underlain with layer of lamina propria
 Serous membrane – slippery membranes
 Simple squamous epithelium lying on areolar connective tissue
 Line closed cavities
 Pleural, peritoneal, and pericardial cavities
 Synovial membranes – lining joint cavities
 Loose connective (areolar) + simple squamous epithelium
 Secretes fluid (synovial fluid) which lubricates, protects &
cushions joint structures