HISTOLOGY
A&P 1
TISSUES
• Tissues - collections of similar cells working together
to perform a function
• Tissue classification based on structure of cells,
composition of noncellular extracellular matrix, and
cell function
• Major types of adult tissues
– Epithelial
– Connective
– Muscle
– Nervous
EPITHELIAL TISSUE
• Cellularity - Consists almost entirely of cells
• Covers body surfaces, lines hollow organs, and forms
glands
–
–
–
–
•
•
•
•
•
Outside surface of the body
Lining of digestive, respiratory and urogenital systems
Heart and blood vessels
Linings of many body cavities
Has apical and basal surfaces
Rests on a basement membrane
Specialized cell contacts bind adjacent cells together
Avascular - no blood vessels
Regenerative -Replaces lost cells by cell division
What is this????
• What is the name of these types of
SIMPLE CUBOIDAL
cells?
• Where would I find it?
KIDNEYS
• What might be its function? SECRETION and ABSORPTION
Name this tissue type…
• What is the name?
• Where is it located?
• What is its function?
Transitional
Bladder, ureters, urethra
Provides stretch
Name this tissue type…
What is this an
image of?
Glomerulus
Bowman’s
capsule
(glomerulus of
kidneys)
Simple
cuboidal
tissue layer
Simple
squamous
tissue layer
• What is the name?
• Where is it located?
• What is its function?
Simple squamous
Alveoli of lungs, kidney glomeruli, lining of
vessels
Filtration (kidneys), diffusion (air
sacs of lungs)
Name this tissue type…
• What is the name?
• Where is it located?
• What is its function?
Simple columnar
Intestinal tract
Absorption, secretion of mucus,
enzymes, and other substances
Name this tissue type…
These
structures
are…
cilia
This is a
goblet
_______
Cell?
• What is the name?
• Where is it located?
• What is its function?
Pseudostratified Ciliated Columnar
Trachea and bronchial tubes
Secretion of mucus, propulsion of
mucus by cilia
Name this tissue type…
• What is the name?
• Where is it located?
• What is its function?
Stratified squamous
Lines mouth, vagina, esophagus, skin
protection
STRATIFIED SQUAMOUS
• Specific types
– Keratinized – contain the protective protein keratin
• Surface cells are dead and full of keratin
– Non-keratinized – forms moist lining of body
openings
CONNECTIVE TISSUE
• Most diverse and abundant tissue
• Main classes
–
–
–
–
Connective tissue proper
Cartilage
Bone tissue
Blood
• Characteristics
– Varying degrees of vascularity
– Nonliving extracellular matrix, consisting of ground
substance and fibers
– Cells are not as abundant nor as tightly packed together as
in epithelium
FUNCTIONS OF CONNECTIVE TISSUE
• Enclose organs as a capsule and
separate organs into layers. Areolar
• Connect tissues to one another.
Tendons and ligaments.
• Support and movement. Bones.
• Storage. Fat.
• Insulation. Fat.
• Transport. Blood.
• Protection. Bone, cells of the immune
system
CELLS OF CONNECTIVE TISSUE
• Fibroblasts - secrete the proteins needed for fiber synthesis
and components of the extracellular matrix
• Adipose or fat cells (adipocytes). Common in some tissues
(dermis of skin); rare in some (cartilage)
• Mast cells. Common beneath membranes; along small blood
vessels. Can release heparin, histamine, and proteolytic
enzymes in response to injury.
• Leukocytes (WBC’s). Respond to injury or infection
• Macrophages. Derived from monocytes (a WBC). Phagocytic;
provide protection
• Chondroblasts - form cartilage
• Osteoblasts - form bone
• Hematopoietic stem cells - form blood cells
• Undifferentiated mesenchyme (stem cells). Have potential to
differentiate into adult cell types.
Extracellular Matrix
• ECM has 3 major components
1. Protein fibers
2. Ground substance
3. Fluid
• Protein fibers
– Collagen fibers. Composed of the protein
collagen. Strong, flexible, inelastic; great tensile
strength (i.e. resist stretch). Perfect for tendons,
ligaments
– Elastic fibers. Contain molecules of protein
elastin that resemble coiled springs. Returns to
its original shape after stretching or
compression. Perfect for lungs, large blood
vessels
– Reticular fibers. Formed from fine collagenous
fibers; form branching networks (stroma). Fill
spaces between tissues and organs.
Name this tissue type…
Adipose
• What is the name?
• Where is it located? Under the skin, around the eyes, kidneys, heart.
• What is its function? Protection, storage
Name this tissue type…
Fibers?
Reticular
Cells?
lymphocytes
• What is the name? Reticular (Loose) Connective Tissue
• Where is it located? Internal skeleton: lymph nodes, spleen
• What is its function? Soft internal skeleton, supports other cell types
Name this tissue type…
What are
these cells
called?
chondrocytes
• What is the name? Hyaline.
• Where is it located? Embryonic skeleton, cover end of bones,
• What is its function? trachea, nose, larynx
Support, reinforce, resist compressive stress.
Name this tissue type…
Fiber?
Collagen
Fiber?
Elastic
Cell?
• What is the name? Aerolar Loose connective .
Fibroblast
• Where is it located? Widely distributed under epithelia
• What is its function? Wraps and cushions organs; inflammation.
Name this tissue type…
??
Fibroblasts
??
Collagen
• What is the name? Dense Connective Tissue.
• Where is it located? Tendons, ligaments, aponeurosis
• What is its function? Attaches muscles to bones, bones to bones.
Name this tissue type…
1. Haversian
Canal
2. Canaliculi
3. Lamella
• What is the name? Osseous tissue.
• Where is it located? Bones
• What is its function? Storage, support
4. Osteocytes
in the Lacuna
??
??
??
What important process
takes place here?
hematopoiesis
• What tissue is this? •
• Where is it found? •
• What is its function? •
Spongy bone or cancellous bone
In the center of flat bones and in the ends of long bones
Support
P
p
MUSCLE TISSUE
• Characteristics
– Cells are referred to as fibers
– Contracts or shortens with force when stimulated
– Moves entire body and pumps blood
• Types
– Skeletal:attached to bones
– Cardiac: muscle of the heart.
– Smooth: muscle associated with tubular
structures and with the skin. Nonstriated and
involuntary.
P
p
SKELETAL
P
p
CARDIAC
P
p
SMOOTH MUSCLE
P
p
NERVOUS
Layers of skin