Tissue
Chapter 4
Link
Tissues
• Tissue:
• 4 Primary Tissue Types
1.
2.
3.
4.
Epithelial
Connective
Muscle
Nervous
http://www.stegen.k12.mo.us/tchrpges/sghs/ksulkowski/images/2
0_Simple_Columnar_Epithelial_Tissue.jpg
Match Tissue Type to Function
1. Epithelial
A. Supports, protects, binds other
tissues together
2. Connective
B. Internal communication
3. Nervous
C. Contracts to cause movement
4. Muscle
D. Forms boundaries between
different environments, protects,
secretes, absorbs, filters
Epithelial Tissue (Epithelium)
•
Two main types (by location):
1. Covering and lining epithelium
2. Glandular epithelium
Forms boundaries
b/w different
environments
http://www.bio.davidson.edu/people/kabernd/BerndCV/Lab/EpithelialInfoWeb/g
oblet%20cells%20.jpg
Functions of Epithelial Tissue
•
•
•
•
•
•
Protection
Absorption
Filtration
Excretion
Secretion
Sensory reception
Characteristics of Epithelial Tissue
1. Cells have polarity
2. Are composed of closely packed cells
3. Supported by a connective tissue reticular
lamina (under the basal lamina)
4. Avascular but innervated
5. High rate of regeneration
Classification of Epithelia
•
Ask two questions:
1. How many layers?
1 = simple epithelium
>1 = stratified epithelium
Classification of Epithelia
2. What type of cell?
•
•
•
Squamous
Cuboidal
Columnar
Note: if stratified,
name according to
apical layer of cells!
Overview of Epithelial Tissues
• For each of the following types of epithelia,
note:
– Description
– Function
– Location
Simple Epithelia
• Single cell layer (usually very thin)
• Concerned with:
– Absorption
– Secretion
– Filtration
• NOT concerned with: protection
• Simple squamous, simple cuboidal, simple
columnar, pseudo stratified columnar
Simple Squamous Epithelium
• Description
• Function
• Location
Note: ENDOTHELIUM AND MESOTHELIUM
Photomicrograph: Simple squamous epithelium
forming part of the alveolar (air sac) walls (125x).
Simple Cuboidal Epithelium
(b) Simple cuboidal epithelium
• Description
• Function
• Location
Photomicrograph: Simple cuboidal
epithelium in kidney tubules (430x).
Simple Columnar Epithelium
(c) Simple columnar epithelium
• Description
• Function
• Location
Photomicrograph: Simple columnar epithelium
of the stomach mucosa (860X).
Pseudostratified Columnar Epithelium
(c) Simple columnar epithelium
• Description
• Function
• Location
Photomicrograph: Pseudostratified ciliated
columnar epithelium lining the human trachea (570x).
Stratified Epithelium
•
•
•
•
2+ cell layers
Regenerate from below
More durable than simple epithelia
Major role: Protection
Stratified Squamous Epithelium
• Description
• Function
• Location
Photomicrograph: Stratified squamous epithelium
lining the esophagus (285x).
Stratified Cuboidal Epithelium
• Description
• Function
• Location
Stratified Columnar Epithelium
• Description
• Function
• Location
http://www.sciencephoto.com/image/115414/large/C0051252Stratified_columnar_epithelium,_urethra-SPL.jpg
Transitional Epithelium
• Description
• Function
• Location
Photomicrograph: Transitional epithelium lining the urinary
bladder, relaxed state (360X); note the bulbous, or rounded,
appearance of the cells at the surface; these cells flatten and
become elongated when the bladder is filled with urine.
Glandular Epithelia
• Gland: one or more cells that secretes and
aqueous fluid
• Classified by:
– Site of product release
• Endocrine
• Exocrine
– Relative number of cells forming the gland
• Unicellular
• Multicellular
Glands
Endocrine
• Ductless glands
• Secrete hormones that
travel through lymph or
blood to target organs
• Examples: Thyroid
Gland, Pituitary Gland
• Covered in Ch. 16
More
numerous!
Exocrine
• Secrete products into
ducts
• Secretions released
onto body surfaces
(skin) or into body
cavities
• Examples: mucous,
sweat, oil, and salivary
glands
Unicellular Exocrine Glands
• Goblet cell and Mucous cell
– Mucin -> mucous
Multicellular Exocrine Glands
• Composed of a duct and a secretory unit
• Classified according to:
1. Duct type
• Simple
• Compound
2. Structure of secretory units
• tubular
• alveolar
• tubuloalveolar
Tubular
secretory
structure
Simple duct structure
Compound duct structure
(duct does not branch)
(duct branches)
Simple tubular
Simple branched
tubular
Example
Example
Compound tubular
Intestinal glands
Stomach (gastric)
glands
Duodenal glands of small intestine
Example
Alveolar
secretory
structure
Simple
alveolar
Simple branched
alveolar
Compound alveolar
Example
Example
Example
No important
example in humans
Sebaceous (oil)
glands
Mammary glands
Surface epithelium
Duct
Compound
tubuloalveolar
Example
Salivary glands
Secretory epithelium
Figure 4.5
Modes of Secretion
Merocrine
• Products are secreted
by exocytosis
• pancreas, sweat and
salivary glands
Holocrine
• Products are secreted
by rupture of gland cells
• sebaceous (oil) glands
Connective Tissue
• Most abundant and widely distributed tissue
type
• Four main classes
1)
2)
3)
4)
Connective Tissue Proper
Cartilage
Bone Tissue
Blood
See Table 4.1
Major Functions of Connective Tissue
1)
2)
3)
4)
5)
Binding and Support
Protection
Insulation
Stores reserve fuel
Transports
Characteristics of Connective Tissue
• Connective tissues have:
– Mesenchyme as their common tissue of origin
– Varying degrees of vascularity
– Cells separated by nonliving extracellular matrix
(ground substance and fibers)
• 3 Structural Elements
– Ground substance
– Fibers
– Cells
Structural Elements of Connective
Tissue
• Ground substance
– Medium through which solutes diffuse between
blood capillaries and cells
– Components:
• Interstitial fluid
• Adhesion proteins (“glue”)
• Proteoglycans
–Protein core + large polysaccharides
–Trap water -> viscosity
Structural Elements of Connective
Tissue
• Connective Tissue Fibers
– Collagen (white fibers)
• Strongest and most abundant type
• Provides high tensile strength
– Elastic (yellow fibers)
• Networks of long, thin, elastin fibers that allow
for stretch/recoil
– Reticular
• Short, fine, highly branched collagenous fibers
Structural Elements of Connective
Tissue
• Cells (see table 4.1)
– Mitotically active and secretory cells = “blasts”
• Fibroblasts, chondroblasts, osteoblasts,
hematopoietic stem cells
– Mature cells = “cytes”
• Chondrocytes, osteocytes
– Other cell types
• Fat cells, white blood cells, mast cells, and
macrophages
Cell types
Macrophage
Extracellular
matrix
Ground substance
Fibers
• Collagen fiber
• Elastic fiber
• Reticular fiber
Fibroblast
Lymphocyte
Fat cell
Capillary
Mast cell
Neutrophil
Figure 4.7
Connective Tissue: Embryonic
• Mesenchyme—embryonic connective tissue
– Gives rise to all other connective tissues
– Gel-like ground substance with fibers and starshaped mesenchymal cells
Connective Tissue Proper
• Types:
– Loose connective
tissue
• Areolar
• Adipose
• Reticular
– Dense connective
tissue
• Dense regular
• Dense irregular
• Elastic
CONNECTIVE TISSUE PROPER
Loose Connective: Areolar
• Description
• Function
• Location
Photomicrograph: Areolar connective tissue, a
soft packaging tissue of the body (300x).
CONNECTIVE TISSUE PROPER
Loose Connective: Adipose
• Description
• Function
• Location
Photomicrograph: Adipose tissue from the
subcutaneous layer under the skin (350x).
CONNECTIVE TISSUE PROPER
Loose Connective: Reticular
• Description
• Function
• Location
Photomicrograph: Dark-staining network of reticular
connective tissue fibers forming the internal skeleton
of the spleen (350x).
CONNECTIVE TISSUE PROPER
Dense Connective: Dense Regular
• Description
• Function
• Location
Photomicrograph: Dense regular connective
tissue from a tendon (500x).
CONNECTIVE TISSUE PROPER
Dense Connective: Dense Irregular
• Description
• Function
• Location
Photomicrograph: Dense irregular
connective tissue from the dermis of the
skin (400x).
CONNECTIVE TISSUE PROPER
Dense Connective: Elastic
• Description
• Function
• Location
Photomicrograph: Elastic connective tissue in
the wall of the aorta (250x).
Connective Tissue: Cartilage
•
•
•
•
•
Stands up to both compression and tension
No nerve fibers, avascular
80% water
Chondroblasts – produce new matrix
Chondrocytes – mature cartilage cells
– Found in small groups in lacunae
CARTILAGE
Hyaline Cartilage
• Description
• Function
• Location
Photomicrograph: Hyaline
cartilage from the trachea (750x).
CARTILAGE
Elastic Cartilage
• Description
• Function
• Location
Photomicrograph: Elastic cartilage
from the human ear pinna; forms the
flexible skeleton of the ear (800x).
CARTILAGE
Fibrocartilage
• Description
• Function
• Location
Photomicrograph: Fibrocartilage of an
intervertebral disc (125x). Special staining
produced the blue color seen.
Connective Tissue: Bone
• Description
• Function
• Location
Photomicrograph: Cross-
sectional view of bone (125x).
Connective Tissue: Blood
• Description
• Function
• Location
Photomicrograph: Smear of human blood
(1860x); two white blood cells (neutrophil in
upper left and lymphocyte in lower right) are
seen surrounded by red blood cells.
Nervous Tissue
• Description
• Function
• Location
Photomicrograph: Neurons (350x)
Muscle Tissue
• Highly cellular, well vascularized
• Movement
• Types
1. Skeletal
2. Cardiac
3. Smooth
MUSCLE TISSUE
Skeletal Muscle
• Description
• Function
• Location
Photomicrograph: Skeletal muscle
(approx. 460x).
Notice the obvious banding pattern and the
fact that these large cells are multinucleate.
MUSCLE TISSUE
Cardiac Muscle
• Description
• Function
• Location
Photomicrograph: Cardiac muscle
(500X); notice the striations, branching
of cells, and the intercalated discs.
MUSCLE TISSUE
Smooth Muscle
• Description
• Function
• Location
Photomicrograph: Sheet of
smooth muscle (200x).
Epithelial Membranes
• Cutaneous membrane (skin)
• Mucous membranes
– Mucosae
• Line body cavities open to the exterior (e.g., digestive
and respiratory tracts)
• Serous Membranes
– Serosae—membranes (mesothelium + areolar
tissue) in a closed ventral body cavity
• Parietal serosae line internal body walls
• Visceral serosae cover internal organs
Mucosa of
nasal cavity
Mucosa of
mouth
Esophagus
lining
Mucosa of
lung bronchi
(b) Mucous membranes line body cavities
open to the exterior.
Figure 4.11b
Parietal
peritoneum
Parietal
pleura
Visceral
pleura
Visceral
peritoneum
Parietal
pericardium
Visceral
pericardium
(c) Serous membranes line body cavities
closed to the exterior.
Figure 4.11c
Steps in Tissue Repair
• Inflammation
• Organization and Restored Blood Supply
• Regeneration and Fibrosis
Scab
Epidermis
Blood clot in
incised wound
Inflammatory
chemicals
Vein
Migrating white
blood cell
Artery
1 Inflammation sets the stage:
• Severed blood vessels bleed and inflammatory chemicals are
released.
• Local blood vessels become more permeable, allowing white
blood cells, fluid, clotting proteins and other plasma proteins
to seep into the injured area.
• Clotting occurs; surface dries and forms a scab.
Figure 4.12, step 1
Regenerating
epithelium
Area of
granulation
tissue
ingrowth
Fibroblast
Macrophage
2 Organization restores the blood supply:
• The clot is replaced by granulation tissue, which restores
the vascular supply.
• Fibroblasts produce collagen fibers that bridge the gap.
• Macrophages phagocytize cell debris.
• Surface epithelial cells multiply and migrate over the
granulation tissue.
Figure 4.12, step 2
Regenerated
epithelium
Fibrosed
area
3
Regeneration and fibrosis effect permanent repair:
• The fibrosed area matures and contracts; the epithelium
thickens.
• A fully regenerated epithelium with an underlying area of
scar tissue results.
Figure 4.12, step 3
Developmental Aspects
• Primary germ layers: ectoderm, mesoderm,
and endoderm
– Formed early in embryonic development
– Specialize to form the four primary tissues
• Nerve tissue arises from ectoderm
• Muscle and connective tissues arise from mesoderm
• Epithelial tissues arise from all three germ layers