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Laboratory Two
Histology
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Histology
• Study of structure and function of tissues
– Groups of cells that are structurally and
functionally the same
– A combination of living and non-living
material
• Go over each microscope
– Illustrate and write anatomical details
– Touch only the fine focus knob
– Pointer helps you locate the assigned structures
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Four Primary Tissue Types
1.
2.
3.
4.
Epithelial - lines & covers surfaces
Connective - protects, supports, & binds
Muscular - contracts & produces movement
Nervous – generates & conducts nerve
impulses
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1. Epithelial Tissue (E.T.)
• Lines, covers surfaces both inside & out
• Consists of many cells, tightly packed together
• Usually arranged in layers (except glands)
– Simple (1 layer) or stratified (2 or more layers)
• Secured to deeper tissue by basement membrane
• A free surface is found opposite basement
membrane
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Specific Types of Epithelial
Tissues are Characterized by:
• Number of layers:
– Simple (1 layer) - secretion, absorption, filtration
– Stratified (>2 layers) – wear & tear
• Cell shape
– Squamous – flat from side, like fried egg from top
(yolk: nucleous)
– Cuboidal - as wide as tall as deep, nucleous in center
– Columnar – tall & thin, nucleous elongated
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Simple Squamous Epithelial Tissue
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Tissue: simple squamous E. T.
Cell: squamous epithelial cell
ID: flattened cells, mosaic shape
Location: alveoli of lungs
Function: diffusion
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Simple Cuboidal Epithelial Tissue
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Tissue: simple cuboidal E.T.
Cell: cuboidal epithelial cell
ID: round centrally located nucleous
Location: salivary glands
Function: secretion
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Simple Columnar Epithelial Tissue
Tissue: simple columnar E. T.
Cell: columnar epithelial cell
ID: elongated nuclei, closer to BM,
one layer
Location: small intestine
Function: secretion of digestive
enzymes, absorption of nutrients
Higher magnification
(showing goblet cells)
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Pseudostratified Ciliated Columnar E. T.
Tissue: P. C. C. E.T.
Cell: columnar epithelial cell with
their elongated nuclei appear in multilayer (cells with different dimension are
arranged in one layer)
ID: ciliated
Location: trachea
Function: protection (cilia moves
mucous along with unwanted
substances in air upwards
Higher magnification
(showing cilia and
goblet cell)
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Stratified Squamous Epithelial Tissue
Tissue: S. S. E.T.
Surface cells: Squamous E. C.
ID: multiple layer, squamous
cells at free surface (As cells
mature, they change shape)
Location: esophagus
Function: protection against
wear & tear
Lower magnification
(see abrupt change in tissue
type at BM)
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Transitional Epithelial Tissue
Tissue: T. E.T.
ID: stratified with cuboidal EC
Location: urinary bladder (distended)
Function: accommodates fluctuation
in the volume of fluid, protects
against caustic effect of urine
Relaxed urinary bladder
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E.T. Assignment
• View each assigned E.T. through
microscopes or as micrographs
• Complete your histology worksheet in your
handout
– Illustrate the specific tissue
– Label the assigned structures on your
illustration
– Record & learn one location and one function
for each tissue
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2. Connective Tissue (C.T.)
• Protects, supports, binds
• Consists of relatively few cells scattered in non-living matrix
• Matrix varies
–
–
–
–
Fluid (e.g. plasma of blood C.T.)
Semi-solid matrix of cartilage
Solid (e.g. bone)
May contain various types of protein fibers arranged in various ways and
with a range of densities
• Cells vary too
–
–
–
–
–
RBCs carry oxygen and WBCs & macrophages are protective
Chondrocytes secrete the matrix in cartilage C.T.
Osteocytes secrete bony matrix in osseous C.T.
Fibroblasts secrete fibers
Adipose cells store fat
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Osseous Connective Tissue
Tissue: Osseous C. T.
Cell: Osteocytes
ID: Cells arranged circularly
around central canal, deposit
the matrix in layers call
lamella, nucleous (dark dots)
Location: skeleton
Function: support, protection
Osteocytes inside lacunae
(magnified)
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Hyaline Cartilage Connective Tissue
Tissue: Hyaline cartilage C. T.
Cell: Chondrocytes
ID: Cells with clear periphery
embedded in a semi-fluid
matrix, nucleous (dark dots)
Location: Capping the end of
bones
Function: support, protection,
cushion
Chondrocytes inside lacunae
(magnified)
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Fibrocartilage Connective Tissue
Tissue: Fibrocartilage C. T.
Cell: Chondrocytes
ID: Cells (dark dots)
embedded in a matrix with
blue collagen fibers
Location: Disks between the
vertebrae of spinal column
Function: cushion
Dense Fibrous Connective Tissue
Tissue: Dense fibrous C. T.
Cell: Fibroblasts
ID: Parallel collagen fibers packed
tightly, nuclei of fibroblasts
(dark dots)
Location: tendon (muscle to bone)
and ligament (bone to bone)
Function: attachment
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Areolar Connective Tissue
Tissue: Areolar C. T.
Cell: Fibroblast (most common)
ID: Irregularly & loosely
arranged collagen and elastic
fibers, dots are nuclei of
fibroblasts
Location: Under the skin
Function: Attachment, support
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Adipose Connective Tissue
Tissue: Adipose C. T.
Cell: Adipocyte, signet ring
cells, or fat cells
ID: Large clear cells with
nuclei pushed to the sides by
fat vacuoles
Location: Breasts, hips
Function: Energy storage,
cushioning, insulation
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Reticular Connective Tissue
Tissue: Reticular CT
Cells: Reticular cells,
blood cells
ID: network of reticular
fibers embedded in cells
Location: spleen
Function: framework to
support free blood cells
Blood Connective Tissue
Tissue: Blood C. T.
Cell: RBC & WBC
ID: RBC – look like life saver, no
nucleous, high in number
WBC – different shapes, have
a nucleous, low in number
Location: blood vessels
Function: gas & nutrients
transport, protection against
infection
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C.T. Assignment
• View each assigned C.T.
• Complete illustrations in your worksheet
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3. Muscle Tissue
(Contracts
producing movement)
• Muscles cells are called fibers
• Cells vary in their number of nuclei and shape, and
whether or not they are banded
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Tissue: Smooth Muscle
Cell: smooth muscle cell
ID: many nuclei crammed in, no striation
Location: stomach
Function: movement of substances
Tissue: Cardiac Muscle
Cell: cardiac muscle cell
ID: intercalated disks, striated
uninucleated
Location: heart
Function: heart pump
Tissue: Skeletal Muscle
Cell: Muscle fiber
ID: Striated with multiple nuclei
Location: arm
Function: movement of body
4. Nervous Tissue
Tissue: Nervous tissue
Cell: Multipolar neuron
ID: Cell body with processes
Location: Nervous system
Function: Conduction of
nerve impulses
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Integumentary System
(Skin)
• This organ system consists of 2 layers:
– Epidermis: Stratified squamous E.T.
– Dermis (papillary and reticular layers):
•
•
•
•
Sebaceous & sweat glands
Hair folicle
Arrector pilli muscle
Meissner corpuscles (sense receptors for light touch)
– Hypodermis (not part of skin): Adipose C. T.
• Pacinian corpuscles (sense receptors for pressure)
• Learn locations of all four primary tissue types, and
the assigned layers and structures on the skin model
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