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Chapter 5 - Tissues
Groups of cells that have specialized
structural and functional roles
There are 4 types of tissues in the
human body.
1. Epithelial – covering, lining
2. Muscle – contracts
3. Connective – bone, adipose (fat),
blood, etc.
4. Nerve – sends impulses
Epithelial Tissue
• Anchored to a basement membrane
that is anchored by its underside to
connective tissue. The basement
membrane is NONLIVING.
• Always has a free space exposed to
the outside or open space internally
- lumen
Characteristics of Epithelial
Tissues
•
•
•
•
Usually lack blood vessels
Readily divide
Tightly packed for protection
Secretion, absorption, excretion, sensory
reception
Organized by layering and cell
shape
By layering
• Simple – extends from basement membrane
to lumen – 1 layer
• Stratified – layered from basement
membrane to lumen area
• Pseudostratified – “seemingly-layered”, but
not
• Nuclei at various levels of cells makes the
appearance of layers
By cell shape
• Squamous – flat cells
• Cuboidal – cube-shaped
• Columnar – elongated and thin – like
columns
Usually both designations are
used to distinguish the type of
epithelial tissue!!!
** Denotes that you should know of an example
or where these are located in the human body.
You will be expected to know this.**
**Simple Squamous Epithelium
What would this be used for or
where would we find it?
• Nuclei are broad and thin
• Diffusion occurs here
• Where?
– Alveoli
– Capillary walls
Simple Cuboidal Epithelium
What would this be used for or
where would we find it?
•
•
•
•
Nuclei are spheres
Secretion and absorption
More protection than previous kind
Where?
– Lines kidney tubules
– Ducts of salivary glands and pancreas
Simple Columnar Epithelium
What would this be used for or
where would we find it?
•
•
•
•
Thicker than either previous ones
Nuclei near basement membrane
Have microvilli and goblet cells
Where?
– Lines uterus
– Lines most organs of digestive tract
**Pseudostratified columnar
Epithelium
What would this be used for or
where would we find it?
• Appear layered, but are not (nuclei at
various levels)
• Commonly have cilia and goblet cells
• Where?
– Line respiratory tract
**Stratified Squamous
Epithelium
What would this be used for or
where would we find it?
• Many layers thick
• Division of cells in deep layer push old out
• Where?
–
–
–
–
Epidermis of skin – keratin
Mouth lining
Vagina lining
Anal canal
Stratified Cuboidal Epithelium
What would this be used for or
where would we find it?
• More protection than simple
• 2 or 3 layers of cuboidal cells that form
lining of lumen
• Where?
– Lines mammary glands
– Sweat glands
– pancreas
Stratified Columnar Epitheliem
What would this be used for or
where would we find it?
• Layers
• Where?
– Male urethra and vas deferens
– pharynx
**Transitional Epithelium
What would this be used for or
where would we find it?
• Changes in response to an increase in
tension
• Where?
– Inner lining of urinary bladder
– Lines urethra
**Glandular Epithelium
There are two basic kinds of
glands:
• Exocrine – secrete products into ducts
• Endocrine – secrete products into tissue
fluid or blood
Cells in these glandular tissues
secrete fluids a number of ways:
• Merocrine – release
watery, protein-rich
fluids by exocytosis
• Apocrine – lose small
portions during
secretion
• Holocrine – entire cell
lyses during secretion
• Kinds of fluids:
• Serous cells – watery
fluids released
• Mucous cells – thicker
mucin released
Section 5.3 – Connective Tissues
•Connective tissue serves many
purposes in the body:
binding
supporting
protecting
forming blood
storing fats
filling space
There is a matrix of fibers, cells,
and ground substance
Usually, the cells can divide and have
a good blood supply and
nourishment.
Major Cell Types:
• Fibroblasts – large, star-shaped
• Macrophages – “wandering cells” – are
scavengers and defensive cells – phagocytes
• Mast cells – large and located near blood
vessels – release heparin and histamine
Connective Tissue Fibers
1. Collagenous Fibers – thick threads of the
protein collagen – form dense, connective
tissue – appear white - in ligaments and
tendons
2. Elastic Fibers – composed of thinner
elastin – allow stretching – appear yellow
– in vocal chords
3. Reticular Fibers – thin, collagenous fibers
– branched for delicate support
Collagen Fibers
Elastin Fibers
Types of Connective Tissue
•
•
•
•
•
•
1.
2.
3.
4.
5.
6.
Loose Connective Tissue (areolar)
Adipose Tissue
Dense Connective Tissue
Cartilage
Bone
Blood
1. Loose Connective Tissue –
(Areolar)
• Delicate, thin,
membranes
• Contains many
fibroblasts located
apart that secrete
collagen and elastin
fibers
• Fills spaces
• Binds skin to
underlying organs
• **See transparency
2. Adipose Tissue
• Fat
• Forms when
connective tissue
stores fat in droplets
and they enlarge to
crowd out other cells
3. Dense Connective Tissue
• Closely-packed, thick,
collagenous fibers
• Few cells
• Very strong
• Ligaments and
Tendons
• See transparency
4. Cartilage
•
•
•
•
Rigid
Chondrocytes
Perichondrium
NO direct blood supply to cartilage
Hyaline Cartilage
• Most common
• Ends of bones, soft
part of nose, between
ribs
Elastic Cartilage
• Elastic fibers
• Flexible
• External ears, larynx
Fibrocartilage
• Tough tissue with
many collagenous
fibers
• Shock absorber
• Pads between bones
5. Bone
• Most rigid of
connective tissue
• Mineral salts and
collagen
• Supports, portects,
forms blood cells,
stores Ca and P
• Osteonic canals
• Osteocytes
• canaliculi
6. Blood
• RBC’s, WBC’s,
platelets, plasma
Section 5.4 – Muscle
Tissues – contractile fibers
Skeletal Muscle
•
•
•
•
Attach to bones
Voluntary
Striations
A nerve impulse
stimulates contraction
Smooth Muscle
• No striations
• Involuntary
• On walls of internal
organs
Cardiac Muscle
•
•
•
•
•
Only in heart
Striations
Involutary
Branched fibers
Intercalated discs
Section 5.5 – Nervous Tissues
Neurons
• In brain, spinal cord,
and peripheral nerves
• Sense and respond by
sending impulses to
muscles or glands
• Coordinate, regulate,
and integrate functions
• **Neuroglial cells