Chapter 5
Tissues
Tissues
• TISSUES: Organization or communities of
similar cells often embedded in nonliving
intracellular material called matrix.
• Histology - The study of tissues
Types of Tissue
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•
•
•
Epithelial
Connective
Muscle
Nervous
Appear within 2 months of
fetal development.
Epithelial Tissue
• Epithelial - lack blood vessels (avascular),
therefore they receive oxygen through
diffusion.
• Function:
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•
•
•
•
Protection - skin, mouth, stomach, etc.
Sensory - skin, nose, ears
Secretion - hormones, mucus, digestive juices
Absorption - respiration, gut
Excretion - urine from kidneys
Structure of Epithelial Tissue
•
•
•
Cells are tightly packed, little intracellular
material.
Always contains one free surface and one
surface attached to a basement membrane =
connective tissue.
Membranous - thin tissue layer
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–
–
–
–
–
Squamous - flat, platelike: blood vessels, alveoli
Columnar - narrow, cylindrical: uterine lining
Cuboidal - cubed shaped: glands
Simple - one layer of cells
Stratified - multiple layers of cells
Pseudostratified columnar - single layer of cylinders
of different heights
Simple Squamous
• Squamous – flat, platelike: blood vessels, alveoli
Simple Columnar
• Columnar – narrow, cylindrical: uterine
lining
Simple Cuboidal
• Cuboidal – cubed shaped: glands
Stratified Squamous
• Stratified –
multiple layers of
cells
Pseudostratified Columnar
• Pseudostratified Columnar – single layer
of cylinders at different heights
Structure of Epithelial Tissue
Continued
• Glandular
- specialized for secretion
- function singularly or in clusters
- exocrine – discharges secretions into ducts (ex. tearducts)
- Types of exocrine glands:
a. Merocrine – releases fluid by exocytosis
(serous cells and mucus cells)
b. Apocrine – cellular product and partial part of cell
released.
c. Holocrine – entire cell released with fluid.
- endocrine – discharges secretions into blood or
intestinal fluid. ex. Thyroid, pituitary
Structure of Epithelial Tissue Continued
Connective Tissue
– Function
• Attachment
– muscle to muscle
– muscle to bone
• Support - organs and body as a whole.
– produce blood cells
– store fat
– serve as framework
• Defense mechanism - fight against infection and
repair tissue damage.
Connective Tissue
– Structure
• Cells far apart
• Have matrix (intercellular material-fluids, fibers,
etc…) between cells.
– Types
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•
•
•
Adipose
Cartilage
Bone
Blood
Types of Connective Tissue
• Adipose – fat cells
– Protective covering around organs
– Insulation
– Distribution is different in males and females
– Stores energy
Types of Connective Tissue
Continued
• Cartilage – dense fibrous
– shock absorbers
– heals very slowly (no direct blood supply)
– Types
• Hyaline – most common, found on the ends of
bone.
• Elastic – more elastic, found on ears
• Fibrocartilage – tough tissue, pads between disks
in vertebrae.
Types of Connective Tissue Continued
Hyaline
Elastic
Fibrocartilage
Types of Connective Tissue
Continued
• Bone
– Specialized to form
blood
– Allows attachment for
muscle
Types of Connective Tissue
Continued
• Blood – liquid state
– Oxygen movement
– Red (transports gases),
white (fight infection),
and platelet cells (blood
clotting)
– Plasma = fluid portion
– Defense against
bacteria
– Ischemia = decrease
oxygen supply to organs
Muscle Tissue
– Function
• Movement through contraction
– Types
• Skeletal
• Smooth
• Cardiac
Muscle Tissue Continued
• Skeletal
– Striated and voluntary
– Muscles attached to bone
– Controllable
Muscle Tissue Continued
• Smooth
– Involuntary
– Found in the walls of hollow internal organs
Muscle Tissue Continued
• Cardiac
– Striated and involuntary
– Only found in the heart
Nervous
– Function
• Regulate and integrate communication
– Types
• Neurons
• Neuroglia
Nervous Continued
• Neurons – send and receive messages
• Neuroglia – connect and support neurons
Nervous Continued
• Structure
– Soma – body of neuron
– Axon – carries impulses away from neuron
– Dendrite – carries impulses to neuron