Histology
Histology
The study of different types of tissues
 Tissue: Cells working together in
functionally related groups

Histology

Separated into four major categories based on
their function and the embryonic tissue of
origin
Tissue
Function
Epithelial
Cover & Protection
Connective
Support
Muscle
Movement & contraction
Nervous
Signaling & communication
Tissue Engineering: How to Build a Heart

ANSWER THESE QUESTIONS IN
COMPELTE SENTENCES INTO YOUR
NOTEBOOK! TITLE THE SECTION: HOW
TO BUILD A HEART
1. Explain why blood supplies pose such a
challenge to tissue engineers?
2. Describe what a scaffold is. Does it have to be
human?
3. What is decellurization?
4. What is recellurization?
5. What are iPS cells?
6. What are some organs that have been
transplanted successfully?
Epithelial Tissue

Location:
◦ Lines nearly every cavity and surface of the human
body
◦ Form glands

Function:
◦ Protect the tissues they cover
◦ Regulate gas and nutrient exchange
◦ Secrete substances such as sweat, hormones,
mucus, and enzymes
◦ Provide sensation with the environment
Epithelial

Classification
◦ Last name of tissue
describes the SHAPE of
cells
◦ Squamous: cells wider
than tall
◦ Cubodial: cells are as
wide as tall, as in “cubes”
◦ Columnar: cells are
taller than they are wide,
like columns
Epithelial

Classification:
◦ First name of tissue
indicates the number of
layers
◦ Simple: One layer of
cells
◦ Stratified: More than
one layer
of cells
Epithelial

Special characteristics:
◦ Cells are packed tightly together, forming a
protective layer around organs
◦ High capacity for regeneration
◦ Produce fluids for lubricating tissues and
organs
◦ Avascular: No capillaries that directly nourish
the cells
 Cells get what they need through diffusion of
nutrients through the basement membrane
Simple Squamous Epithelium
Single layer of flat cells with disc-shaped
nuclei
 Function:

◦ Passage of materials by passive diffusion and
filtration
◦ Secrete lubricating substances in serosae
Simple Squamous Epithelium

Location
◦
◦
◦
◦
Renal corpuscles
Alveoli of lungs
Lining of heart, blood, and lymphatic vessels
Lining of ventral body cavity
Simple Cuboidal Epithelium
Single layer of cube-like cells with large,
spherical nuclei
 Function:

◦ Secretion and absorption
Simple Cuboidal Epithelium

Location:
◦ Kidney tubules
◦ Secretory portions of small glands
◦ Ovary and Thyroid follicles
Simple Columnar Epithelium

Single layer of column-shaped cells with
oval nuclei
◦ Some may have cilia

Function:
◦ Absorption
◦ Secretion of mucus, enzymes, and other
substances
◦ Ciliated type propels mucus or reproductive
cells by ciliary action
Simple Columnar

Location:
◦ Non-ciliated: lines digestive tract, gallbladder,
ducts of some glands
◦ Ciliated form: lines small bronchi, uterine
tubes, uterus
Connective Tissues

Most abundant tissue type in the body
◦ Ex: blood, bone, cartilage, tendons, ligaments…
Made up of fibers and extracellular
components in the embedded in fluid
 Types of Connective Tissues

◦
◦
◦
◦
Loose Connective Tissue
Dense Connective Tissue
Cartilage
Other Tissues
Connective Tissue

Function:
◦
◦
◦
◦
◦
Protect
Store energy
Transport
Insulate
Connect all body
tissues
Cartilage

Hyaline:
◦ Provides support while still being pliable, most abundant
form
◦ Found in the ends of long bones, nose, trachea, and
larnyx

Elastic
◦ Provides support while still able to stretch
◦ Supports external ear, epiglottis
Cartilage

Fibrocartilage:
◦ Provides strong support and handles heavy
pressure
◦ Found in intervertebral discs, pubic symphysis,
discs of knee joints
Muscle Tissue
Cells are extremely long and contain
protein fibers capable of contracting
 Separated into 3 main types:

◦ Skeletal muscle tissue
◦ Smooth muscle tissue
◦ Cardiac muscle tissue

TedEd Types of Muscle Tissue
Skeletal Muscle Tissue

Voluntary muscle
◦ Can be contracted voluntarily
◦ Function in movement and maintenance of
posture
◦ Visible striations

Makes up the muscles that are attached to
our skeleton
Smooth Muscle Tissue

Involuntary muscle
◦ Muscle does not contract voluntarily
◦ Lines most of the organs of the body
◦ No visible striations

Found in:
◦
◦
◦
◦
◦
GI Tract
Respiratory Tract
Blood vessels
Bladder
Uterus
Cardiac Muscle
Heart, extremely dense, strong tissue
 Involuntary
 Large number of mitochondria to provide energy
for the continuous contracting of the heart
 Striated like muscle tissue

Nervous Tissue
Found in the brain, spinal cord, and nerves
 Consists of 2 main cells

◦ Neurons
◦ Neuroglia cells

Responsible for communication