Download The Tissue Level of Organization

CHAPTER 4
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Study of different tissues
Abnormal cells and tissues can be compared
to normal tissues to identify disease, such as
cancer
Being able to know and recognize normal
tissues under the microscope is the first step
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PRACTICE
 There are thousands of images, virtual labs and
practice quizzes online
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DON’T MEMORIZE
 Tissues from the same organ will look vastly different
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RECOGNIZE PATTERNS
 Don’t get lost in the big picture, look for patterns in
how cells are organized
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FORM = FUNCTION
 Keep in mind the function of the tissue and the organ
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Tissues are collections of cells and cell
products that perform specific, limited
functions
Histology = study of tissues
There are 4 types of tissues
1. Epithelial – cover and protection
2. Connective - support
3. Muscle - movement
4. Neural – signaling and communication
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ONLY!!!
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Covers body surfaces and lines cavities
Forms most glands
Characteristics
 Cells are tightly packed together
 Free surface exposed to environment = APICAL SURFACE
 Attached to underlying connective tissue (basement membrane)
 Avascular (no blood supply) – nutrients must diffuse
 Continually replaced at exposed surface
1.
2.
3.
4.
Protection from abrasion, dehydration, destruction
Regulate gas and nutrient exchange
Provide sensation
Secrete substances such as sweat, hormones, mucus and
enzymes
First name indicates number of layers
1.
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Simple: one layer of cells
Stratified: more than one layer of cells
Pseudostratified: appears to be stratified but is not
Second name describes the shape of the cells
2.
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Squamous: thin and flat
Cuboidal: cube shaped
Columnar: tall, slender rectangles
1. Simple Squamous
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Description: single layer of flat cells
Functions: passage of material by simple diffusion and filtration;
secretes lubricating substances
Location: alveoli of lungs
1. Simple Squamous
Simple squamous
lining the walls of
the capillary
2. Simple Cuboidal
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Description: single layer of cube-shaped cells
Functions: absorption and secretion
Locations: Sweat glands, ducts, kidney tubules, thyroid gland
3. Simple columnar
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Description: single layer, tall cells
Function: protection, absorption, secretion
Locations: Lining of the nasal passages, stomach and
intestines
Other: : Cells are very long and often have cilia
4. Stratified Squamous
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Description: many layers of flat cells (look at the shape of the
cells at the apical surface)
Functions: Protection from abrasion, pathogens, and chemicals
Locations: surface of skin, lining of mouth, throat, esophagus,
rectum, anus and vagina
5. Pseudostratified ciliated columnar
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Description: single layer of columnar cells but the position of
the nuclei make it appear as there are many layers; often ciliated
Functions: Protection and secretion
Locations: lining of nasal cavity, trachea and bronchi and
portions of male reproductive tract
6. Transitional
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Description: transitions from one shape
to the next; often has a scalloped apical
edge
Functions: permits expansion and recoil
after stretching
Locations: bladder, renal pelvis, ureters
Pseudostratified
Practice Identifying
epithelial tissues
Practice Identifying
epithelial tissues
Simple
Squamous
Simple Cuboidal
Practice Identifying
epithelial tissues
Practice Identifying
epithelial tissues
Stratified
Squamous
TRANSITIONAL
Practice Identifying
epithelial tissues
Practice Identifying
epithelial tissues
Simple
Columnar
1. Connective Tissue Proper
a) Loose Connective
b) Adipose
c) Dense Connective
2. Cartilage
a) Hyaline
b) Elastic
c) Fibrocartilage
3. Other Tissues
a) Bone
b) blood
1. Loose Connective Tissue (Areolar Tissue)
 Structure: More ground substance, less fibers
 Functions: cushion, support, movement, defense
against pathogens
 Locations: between other tissues and organs, beneath
skin, digestive, respiratory and urinary tracts, between
muscles, around blood vessels, nerves and joints
1. Loose Connective Tissue (Areolar Tissue)
2. Adipose (FAT)
 Structure: Fibroblasts enlarge and store fat, very little
matrix
 Functions: stores energy, insulates and protects organs
 Locations: beneath the skin and around organs
especially at sides, buttocks, breasts, around eyes and
kidneys
2. Adipose Tissue
3. Dense Regular (Fibrous)
 Structure: tightly organized bundles of collagen
 Functions: Tendons (connect muscles to bone) and
Ligaments (connect bones to bones)
3. Dense Regular
Gel-type ground substance
For shock absorption and protection
No blood vessels
Types of cartilage include
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Hyaline cartilage
Elastic cartilage
Fibrous cartilage
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Hyaline Cartilage
Most common
Very fine, white collagenous fibers
Covers ends of bones and joints and respiratory
passages
Elastic Cartilage
2.
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Elastic fibers in addition to collagen
More flexible and elastic
External ear
Fibrous Cartilage (fibrocartilage)
3.
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Very tough, large numerous collagen fibers
Provides strong support and handles heavy pressure
Intervertebral discs
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Most rigid connective tissue
Rigid due to mineral salts
Bone cells called osteocytes
Periosteum (Covers bone surfaces)
HOMEWORK
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Physical barriers
Line internal spaces of organs and tubes that
open to the outside
Line body cavities
Different types of membranes\
 Mucous
 Serous
 Cutaneous
 Synovial
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Mucous = protection
Line passages that have external connections
 Lining of digestive, respiratory, urinary and
reproductive tracts
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Epithelial surfaces are moist to reduce friction
and help absorption and excretion
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Line cavities not open to outside
Are thin but strong
Have fluid to reduce friction
Three serous membranes
 Pleura – lungs
 Peritoneum – abdomen
 Pericardium - heart
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Outer covering of body
Skin
Thick, waterproof and dry
Stratified keratinized squamous epithelium
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Line freely movable joint cavities
Secrete synovial fluid into joint cavity –
provides lubrication
Protects the end of bones
Lacks a true epithelium
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Specialized for contraction
Produces all body movement
Three types
1. Skeletal
2. Cardiac
3. Smooth
1.
Skeletal Muscle
 Voluntary
 Cells are long, cylindrical, striated and multinucleate
 Specialized for contraction
2.
Cardiac Muscle
 Involuntary
 Cells are short, branched and
striated usually with a single
nucleus
 Found only in the heart
3.
Smooth muscle
 Involuntary
 Cells are short, spindle-shaped and non-striated with a
single central nucleus
 Walls of hollow, contracting organs (blood vessels
digestive, respiratory, urinary and reproductive tracts)
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Specialized for conducting electrical impulses
Rapidly senses internal or external environment
Processes information and controls responses
Concentrated in the central nervous system
 Brain and spinal cord
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Two kinds of neural cells
 Neurons = neurons
 Neuroglia = supporting cells
Tissues respond to injury to maintain homeostasis
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Inflammatory response
The tissue’s first response to injury
Signs and symptoms of the inflammatory response
 Swelling, redness, heat, pain
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Can be triggered by
 Trauma (physical injury) or infection
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Fibroblasts produce dense network of
collagen fibers (scar tissue)
Most successful in…
 epithelia, connective tissues and smooth muscle
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Least successful in…
 Neural tissue, cardiac muscle
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Speed and efficiency of tissue repair decrease
with age due to
 Slower rate of energy consumption (metabolism)
 Hormonal alterations
 Reduced physical activity
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Osteoporosis – age related reduction in bone
strength of women
Tissue
ID
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