Tissue Types Overview
 Tissue Definitions
 Epithelial Tissue
• Simple and Stratified
 Connective Tissue
• Characteristics
• Bone, Cartilage, Loose Conn.
• Dense Connective
 Blood
 Muscle Tissue
• Skeletal, Cardiac, and Smooth
 Nervous Tissue
 Tissue Repair
 Tissue Development and Aging
Table 4.1
Connective Tissue: Cartilage
 Three types of cartilage:
• Hyaline cartilage
• Elastic cartilage
• Fibrocartilage
Connective Tissue Types: Cartilage
 Hyaline cartilage
Found in larynx, joints, connecting ribs, tip of nose
Connective Tissue Types: Cartilage
 Elastic cartilage
Found in the external ear, auditory tube, larynx
Connective Tissue Types: Cartilage
 Fibrocartilage
Found between vertebrae in the spine
Figure 3.19c
Connective Tissue Types: Dense
 Dense connective tissue
Found in tendons, ligaments, lower layers of skin
(d) Connective tissue proper: dense connective tissue, dense regular
Description: Primarily parallel
collagen fibers; a few elastic fibers;
major cell type is the fibroblast.
Collagen
fibers
Function: Attaches muscles to
bones or to muscles; attaches bones
to bones; withstands great tensile
stress when pulling force is applied
in one direction.
Location: Tendons, most
ligaments, aponeuroses.
Nuclei of
fibroblasts
Shoulder
joint
Ligament
Photomicrograph: Dense regular connective
tissue from a tendon (500x).
Tendon
Figure 4.8d
(e) Connective tissue proper: dense connective tissue, dense irregular
Description: Primarily
irregularly arranged collagen
fibers; some elastic fibers;
major cell type is the fibroblast.
Nuclei of
fibroblasts
Function: Able to withstand
tension exerted in many
directions; provides structural
strength.
Location: Fibrous capsules of
organs and of joints; dermis of
the skin; submucosa of
digestive tract.
Fibrous
joint
capsule
Collagen
fibers
Photomicrograph: Dense irregular
connective tissue from the dermis of the
skin (400x).
Figure 4.8e
(f) Connective tissue proper: dense connective tissue, elastic
Description: Dense regular
connective tissue containing a high
proportion of elastic fibers.
Function: Allows recoil of tissue
following stretching; maintains
pulsatile flow of blood through
arteries; aids passive recoil of lungs
following inspiration.
Elastic fibers
Location: Walls of large arteries;
within certain ligaments associated
with the vertebral column; within the
walls of the bronchial tubes.
Aorta
Heart
Photomicrograph: Elastic connective tissue in
the wall of the aorta (250x).
Figure 4.8f
Connective Tissue Types: Adipose
 Adipose tissue
Found around organs (e.g.
kidneys), eyballs, hips, and
breast
A signet ring
Figure 3.19f
Connective Tissue Types: Reticular
 Reticular connective tissue
Found in spleen, bone marrow, and lymph nodes
Connective Tissue Types: Blood
 Blood
Tissue Types Overview
 Tissue Definitions
 Epithelial Tissue
•
Simple and Stratified
 Connective Tissue
•
Characteristics
•
Bone, Cartilage, Dense
•
Connective, Loose Connective
 Blood
 Muscle Tissue
•
Skeletal, Cardiac, and Smooth
 Nervous Tissue
 Tissue Repair
 Tissue Development and Aging
Muscle Tissue
 Function is to produce movement
 Three types
• Skeletal muscle
• Cardiac muscle
• Smooth muscle
Muscle Tissue Types: Skeletal
 Skeletal muscle
Found in all muscle connected to bones
Figure 3.20a
Muscle Tissue Types: Cardiac
 Cardiac muscle
Found exclusively in the heart
Figure 3.20b
Muscle Tissue Types: Smooth
 Smooth muscle
Found in walls of hollow organs like stomach, bladder,
uterus, blood vessels, intestines
Tissue Types Overview
 Tissue Definitions
 Epithelial Tissue
•
Simple and Stratified
 Connective Tissue
•
Characteristics
•
Bone, Cartilage, Dense
•
Connective, Loose Connective
 Blood
 Muscle Tissue
•
Skeletal, Cardiac, and Smooth
 Nervous Tissue
 Tissue Repair
 Tissue Development and Aging
Nervous Tissue
Found in brain, spinal cord, and extensions all over the body
Tissue Repair
 Types of Repair
• Regeneration
 Replacement of destroyed tissue by the same kind of cells
• Fibrosis
 Repair by dense fibrous connective tissue (scar tissue)
 Determination of method
• Type of tissue damaged
• Severity of the injury
Events in Tissue Repair
1. Inflammatory Reaction sets the stage
•
Mast cells release histamines
•
Release of histamines cause vasodilation
•
 temperature,  swelling
•
Clotting proteins
•
Walling-off of injured area, scab
•
Leukocytes: neutrophils, macrophages
2. Organization restores blood supply
•
Formation of granulation tissue
•
Fibroblasts bind with collagen
•
Phagocytosis by macrophages
3. Regeneration of surface epithelium
•
Fibrosed area matures, contracts
•
Scar tissue forms
Regeneration of Tissues
 Tissues that regenerate easily
• Epithelial tissue
• Fibrous connective tissue and bone
 Tissues that regenerate poorly
• Skeletal muscle
 Tissues that are replaced largely with scar tissue
• Cardiac muscle
• Nervous tissue within the brain and spinal cord
Development of Tissues
Regenerative
Non-regenerative (amitotic)
3 Primitive Germ Layers:
• Endoderm: Forms gut tube, digestive system
• Mesoderm: Forms muscle, mesenchyme (embryonic connective tissue) -> osteoblasts,
fibroblasts, chondrocytes -> bone, blood, other connective tissue
• Ectoderm: Forms nervous tissue, skin
Aging of Tissues
Normal tissue changes
• Hyperplasia (enlargement)
• Atrophy (reduction)
Abnormal tissue changes
• Neoplasms
Some Tissue Changes in Aging
• Skin loses elasticity, epithelia membranes thin
• Exocrine glands less active; skin dries
• Decreased endocrine function and slowing of
metabolism
• Bones become porous
• Muscles atrophy
Summary
 Tissue Definitions
 Epithelial Tissue
•
Simple and Stratified
 Connective Tissue
•
Characteristics
•
Bone, Cartilage, Dense
•
Connective, Loose Connective
 Blood
 Muscle Tissue
•
Skeletal, Cardiac, and Smooth
 Nervous Tissue
 Tissue Repair
 Tissue Development and Aging