Transcript Chapter 3-2

Chapter 4 - 2
Histology
Tissues and Membranes
Adipose Connective Tissue
Mature cells are specialized for storage of
triglycerides and largest cells in body.
 Adipocytes are derived from fibroblast cells.
 Cells fill up with triglycerides which push cell
nuclei to the periphery of the cell.
 Most adipose in adults is white adipose tissue.
 Brown adipose tissue gets its coloration from
rich vascular supply and is less common.
 Functions as insulation, energy storage,
protects and supports organs.
 Usually found with or close to areolar tissue.

Adipose Connective Tissue
Reticular Connective Tissue

Composed of interlacing reticular fibers with
various types of cells interspersed among the
fibers.

Forms the stroma of the liver, spleen and
lymph nodes and helps to bind smooth muscle
cells.
Reticular Connective Tissue
Dense Regular Connective Tissue
Composed of bundles of collagen fibers
regularly arranged in parallel patterns.
 Fibroblasts are interspersed between the
collagen fibers.
 Main component in ligaments, tendons,
aponeuroses and fascia.
 Has a wavy appearance on slides.
 Forms tendons to attach muscles to bone and
ligaments to attach bones to bones.

Dense Regular Connective Tissue
Dense Irregular Connective Tissue
Similar to areolar connective tissue but collagen
fibers are much thicker.
 Fibers run in different planes making this a very
strong tissue and resistant to strong tensions
from all directions.
 Found in dermis; fibrous capsules surrounding
kidneys, bones and lymph nodes; and in the
submucosa of the GI tract.

Dense Irregular Connective Tissue
Dense Irregular Connective Tissue
Elastic Connective Tissue

High content of branching elastic fibers.

Very distensible, allows for stretching and
returning to original shapes.

Found in lung tissue, large elastic arteries, and
suspensory ligaments .
Elastic Connective Tissue
Cartilage

1.
2.
3.
Three types:
Hyaline cartilage
Fibrocartilage
Elastic cartilage
Hyaline Cartilage
Consists of a dense network of collagen fibers
embedded in a gel-like ground substance
containing chondroitin sulfate with
chondrocytes situated in lacunae.
 Matrix appears homogeneous and clear of
fibers.
 The predominant cartilage found in the
trachea, bronchi, articular cartilages, nose and
ribs.

Hyaline Cartilage
Elastic Cartilage

Consists of chondrocytes located in lacunae
surrounded by a network of elastic fibers.

Found in epiglottis, pinna of the ear and the
internal auditory canal (Eustachian tube)
Elastic Cartilage
Fibrocartilage

Consists of chondrocytes in lacunae scattered
among bundles of collagen fibers.

Most predominant in intervertebral discs, pubic
symphysis, and menisci of knee joints.
Fibro cartilage
Bone
Two types: Compact and Spongy

Compact bone consists of osteons (Haversian
systems) osteocytes in lacunae and lamellae.

Spongy bone is characterized by trabeculae
surrounded by spaces filled with red bone
marrow
Bone

Two types: a) Compact b) Spongy
Compact Bone
Blood
Consists of liquid portion (plasma)
 Erythrocytes (RBC)
 Leukocytes (WBC’s = 5 types)
 Platelets (Thrombocytes)


Functions to carry nutrients and waste products
to and from tissues as well as protect body
against foreign invaders and infection. Also
active against bleeding maladies and
hemorrhage.
Blood
Erythrocytes



Small anucleated cells in blood
Donut shaped
Most numerous cells in a blood smear
Leukocytes
Includes Agranulocytes and Granulocytes.
 Agranulocytes: lymphocytes and monocytes
 Granulocytes: neutrophils, eosinophils and
basophils
 Never Let Monkeys Eat Bananas (Most
abundant to least abundant)
 neutrophils>lymphocytes>monocytes>eosinophils>basophils

Leukocytes
Neutrophils
Medium-sized leukocytes (10-12 um)
 Most numerous white blood cells (60-70%)
 Granular cytoplasm but granules not easily
discernable
 Nucleus is multi-lobed and variable shaped

Lymphocytes
Nucleus is spherical and dark purple inside
pale blue cytoplasm (5-17 um)
Second most prominent wbc (20-25%)
Monocytes
Largest of the wbc’s (14-24 um)
 Third most abundant wbc’s (3-8%)
 Nucleus is “U” or kidney shaped
 Cytoplasm is bluish in color

Eosinophils
•Nucleus is bi-lobed
•Reddish cytoplasmic granules
•Similar size to neutrophils (10-14 um)
•Fourth most abundant wbc’s (2-4%)
Basophils
Nucleus is bilobed; (8-10 um)
 Large blue-purple cytoplasmic granules
 Least common wbc (0.5-1%)

Leukocytes summary
Body membranes
Cutaneous membranes = skin (more later)
 Mucous membranes = line body cavities that
open directly to the exterior (digestive,
respiratory, reproductive and urinary tracts).
 Serous membranes = line body cavities not
directly open to exterior
 Synovial membranes = line joint cavities

Mucous membranes

Vary considerably throughout the body where they
exist.

Are an important barrier to foreign microbes and
agents that could invade the body.

Composed of epithelial tissues with underlying
connective tissue support.

Contain numerous mucus and goblet cells that keep
the membranes moist.
Serous Membranes (SM)
Composed of areolar (loose) connective tissue
and covered by simple squamous epithelium
 Serous membranes line body cavities that are
not exposed to the outside and also cover the
organs within the cavities. There are 2 layers
with a space between them.
 Parietal layer = attached to body wall
 Visceral layer = covers and attaches to organs
 Serous fluid = clear fluid between two layers
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Specialized Serous Membranes

Pericardium =
serous membrane
surrounding the
heart as a sac and
covering the heart.

Pleura = serous
membranes lining
the thoracic cavity
and covering the
lungs.
Specialized Serous Membranes

Peritoneum = serous
membrane lining the
abdominal cavity and
covering most
abdominal organs,
except the kidneys,
duodenum, and parts
of the colon.
Synovial membranes
Line joint cavities
 Consist of fibrous
connective tissue and
enclose the joint
cavities.
 This will be covered in
greater detail in the
next unit when we
talked about joints and
articulations.
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Muscle
Three types
1.
2.
3.
Skeletal muscle
Smooth muscle
Cardiac muscle
Skeletal Muscle

Most prominent characteristic is parallel large
cylindrical cells with multiple nuclei.

Cross-striations are present.

Voluntary muscle; under willful control.

Attached to bones and tendons and skin.
Skeletal Muscle
Cardiac muscle
Branching cells that interdigitate as a
syncytium.
 Intercalated discs present at cell junctions.
 Generally uni-nucleate
 Found in walls of heart only (myocardium)
 Characterized by auto-rhythmicity
 Involuntary muscle
 Cross striations are present.

Cardiac muscle
Smooth Muscle
Cells are spindle shaped
 Single nucleus


DOES NOT HAVE cross striations

Involuntary muscle

Found in walls of most hollow organs (vessel
walls, intestinal tract walls, reproductive tract,
urinary tract, respiratory tract, etc.).
Smooth Muscle
Nervous tissue

Two cell type: Neurons and neuroglial cells

Neurons are branching elongated cells, highly
specialized for generating nerve impulses.

Neuroglial cells are of multiple shapes and
functions and are considered as supporting
cells.
Nervous tissue

Neurons and neuroglial cells