1. The Body Tissues
Chapter 3
Page 74
Human Anatomy and Physiology

2. I. Body Tissues
 The human body starts out as a single cell when
the sperm fertilizes the egg.
 These cells divide into millions of cells that are
specialized for particular functions.
 Some become muscle cells, others transparent
lens of the eye, still others into skin cells, etc.
 This is called division of labor – where certain
groups of specialized cells perform functions
that benefit the entire organism.

3. I. Body Tissues
 The disadvantage of cell specialization is
that if certain groups of cells are disabled or
damaged it could damage the entire
organism.
 Ex – The contractions of the heard depend
on a small group of specialized cells. If
these are damaged, the heart will either stop
or function poorly.

4. I. Body Tissues
 Groups of cells that are similar in structure
and function are called tissues.
 There are 4 primary tissues types LEARN
THEM!
– Epithelium - covering
– Connective - support
– Nervous - control
– Muscle - movement

5. II. Epithelial Tissue
 Makes up the lining, covering, and
glandular tissue of the body.
 Functions of epithelium include:
– Protection
– Absorption
– Filtration
– Secretion

6. II. Epithelial Tissue
 General Characteristics
– Fit closely together to form continuous sheets.
– The membranes always have one free
(unattached) surface called the apical surface
the other side it attached to a basement
membrane.
– They have no blood supply of their own. They
depend on diffusion from capillaries.
– Can regenerate easily.

7. III. Classification of
Epithelium
 Epithelium can be classified in general
terms as either:
– Simple (one layer of cells) or
– Stratified (more than one cell layer.

8. I. Classification of
Epithelium
 Types of Simple Epithelia – Since they are
thin, they usually are not involved with
protection, but rather absorption, secretion,
and filtration.

9. III. Classification of Epithelium
 Simple Squamous
Epithelium
– Single layer of thin
squamous cells resting on a
basement membrane.
– Fit together like floor tiles.
– Located in air sacs of
lungs, capillary walls, and
covers organs in ventral
cavity

10. III. Classification of Epithelium
 Simple Cuboidal
Epithelium
– One layer of cuboidal
cells resting on a
basement membrane
– Common in glands and
ducts
– Walls of kidney
tubules and covers the
surface of the ovaries

11. III. Classification of Epithelium
 Simple Columnar
Epithelium
– Single layer of tall
cells that fit closely
together.
– Goblet cells, which
produce lubricating
muscus.
– Entire length of
digestive tract from
stomach to anus.
– Mucous membranes

12. III. Classification of Epithelium
 Pseudostratified Columnar Epithelium
– All cells rest on basement membrane
– Some are shorter than others giving the false
impression that it is stratified (made up of more
than one layer)
– Lines respiratory tract

13. III. Classification of Epithelium
 Stratified Epithelia consists of 2 or more
cell layers. These are primarily made for
protection.

14. III. Classification of Epithelium
 Stratified squamous – most common in body
– Several layers of cells.
– Free edge is squamous. Cells close to basement membrane is
either cuboidal or columnar.
– Esophagus, mouth, outer part of skin. High use areas.

15. III. Classification of Epithelium
 Stratified cuboidal and
Stratified Columnar
– 2 cell layers with surface
being cuboidal in shape
– Surface cells of Stratified
columnar are columnar
cells, but basal cells vary in
size and shape.
– Both are rare in body and
only found in the ducts of
large glands.

16. III. Classification of Epithelium
 Transitional
Epithelium
– Highly modified
stratified sqamous
epithelium
– Forms lining of
urinary bladder,
ureters, and part
of the urethra.
– Aids in stretching

17. III. Classification of Epithelium
 Glandular Epithelium
– Gland consists of one or more cells that make and
secrete a particular product.
– Product is called a secretion.
– Two types of glands
 Endocrine glands – (ductless glands) – Diffuse into the
blood to be used in the body – include thyroid,
adrenals, and pituitary
 Exocrine glands – (retain their ducts) – Empty through
ducts to the epithelial surface – include sweat and oil
glands, liver, and pancrease.

18. I. Connective Tissue
 Connects body parts.
 Found everywhere in the body.
 Most abundant and widely distributed of all
body tissue types.

19. IV. Connective Tissue
 Common characteristics
– Most are well vascularized (good blood supply)
except for tendons and ligaments with poor
blood supply and cartilages which are avascular.
These heal poorer than the well vascularized
tissue.
– Extracellular Matrix – made up of different
types of cells plus varying amounts of a
nonliving substance outside the cells called
extracellular maxtrix.

20. IV. Connective Tissue
 Extracellular matrix is what makes
connective tissue different from all other
tissue types.
 Produced by connective tissue cells and
secreted to their exterior.
 Matrix may be liquid, semisolid, gel-like or
very hard.
 Can bear weight, can stretch, can take abuse.

21. IV. Connective Tissue
 Different degrees of strength
– Fat tissue is mostly cells with a soft matrix
– Bone and cartilage have few cells and large amounts
of hard matrix which makes them extremely strong.
– Fibers that make up the matrix are
 Collagen fibers (white)
 Elastic fibers (yellow)
 Reticular fibers (fine collagen)
 Protecting, support, binding together

22. V. Types of Connective Tissue
 Most important thing to remember about the
different tissue types is
– Fiber type
– Number of fibers
 From most rigid to the softest are =
– Bone, cartilage, dense connective tissue, loose
connective tissue, and blood.

23. V. Types of Connective Tissue
 Bone
– AKA osseous tissue composed of bone cells
sitting in cavities called lacunae and surrounded
by layers of a very hard matrix that contains
calcium slats and large numbers of collagen
fibers.
– Exceptional protection and support

24. V. Types of Connective Tissue
 Cartilage
– Less hard and more flexible than bone.
– Few places in the body.
– The most common type is hyaline cartilage.
 Abundant collagen fibers hidden by a rubbery matrix with
a glassy blue-white appearance.
 Attaches ribs to breastbone, covers ends of bone, fetus
skeleton
– Elastic cartilage – external ear
– Fibrocartilage – vertebral disks

25. V. Types of Connective Tissue
 Dense Connective Tissue
– AKA dense fibrous tissue
– Collagen fibers as main matrix
– Crowded between collagen fibers are rows of
fibroblasts (fiber-forming cells) that make fibers.
– Make up tendons (attach muscles to bones) and
ligaments (connect bones to bones)
– Ligaments are more stretchy and contain more
elastic fibers that tendons.
– Makes up lower layers of skin

26. V. Types of Connective Tissue
 Loose Connective Tissue
– Softer, have more cells and fewer fibers than
the other types

27. V. Types of Connective Tissue
 Types of Loose Connective Tissue
– Areolar Tissue – soft tissue that cushions and
protects body organs.
 Universal packing and glue to hold the internal organs
together.
 When viewed under the microscope it appears to be
mostly open space.
– Adipose Tissue – commonly called fat tissue
 Oil occupies most of the cell compressing nucleus. Cell
looks empty.
 Subcutaneous tissue beneath skin, insulates body, protects
organs, stored for energy in hips, stomach, and breasts.

28. V. Types of Connective Tissue
 Reticular Connective Tissue
– Delicate network of interwoven reticular fibers
associate with reticular cells which resemble
fibrobasts.
– Located in lymphoid organs such as lymph
nodes, spleen, and bone marrow.

29. V. Types of Connective Tissue
 Blood
– AKA vascular tissue
– Blood cells surrounded by a non-living matrix
called blood plasma.
– The fibers of blood are soluble protein
molecules that become visible only during
blood clotting
– Carries nutrients, waste, respiratory gases and
other substances throughout the body.

30. VI. Types of Muscle Tissue
 There are three types of muscle tissue.
– Skeletal muscle is packaged by connective tissue
into sheets which are attached to the bones.
 These are voluntary muscles (you control
them).
 Usually called meat or flesh
 When they contract they pull on bones or skin
causing body movements and facial
expressions.
 They are striated.

31. VI. Types of Muscle Tissue
– Cardiac Muscle
 Only found in the heart.
 Acts as a pump and propels blood through
the blood vessels.
 It has striations, but cells are uninucleate,
branching cells that fit tightly together.
(intercalated disks)
 Involuntary muscle – we cannot consciously
control the activity.

32. VI. Types of Muscle Tissue
– Smooth Muscle
 AKA visceral muscle
 No striations are visible.
 Single nucleus and spindle-shaped (pointed at each
end)
 Found in the walls of hollow organs (stomach,
bladder, uterus, blood vessels)
 Muscle contraction forces movement through the
organ.
 Much slower than other types of muscles.
 Involuntary
 Peristalsis – wavelike motion that keeps food
moving through the small intestine.

33. VII. Nervous Tissue
 Composed of cells called
neurons
– Highly specialized to
receive and transmit nerve
impulses and supporting
cells.
– Neurons are important in
controlling body
processes
– Found in brain, spinal
cord, and nerves.

34. VIII. Tissue Repair
 Two ways of tissue repair:
– Regeneration – Tissue is replaced
with the same kind of cells
– Fibrosis – Repair by dense (fibrous)
connective tissue (scar tissue)

35. VIII. Tissue Repair
 Which type of repair occurs depends
on
– The type of tissue damaged
– The severity of the injury
 Clean cuts (incisions) heal much more
successfully than ragged tears
(lacerations)

36. VIII. Tissue Repair
 Steps to Tissue Repair
– Clotting proteins create a clot which stops the
loss of blood, holds the edges of the wound
together and prevents bacteria and other
harmful substances from spreading to
surrounding tissues
– Clot dries and forms a scab.

37. VIII. Tissue Repair (con’t)
– Granulation tissue forms next
 Pink tissue composed largely of capillaries that
grow into the damaged area from undamaged blood
vessels nearby.
 Fragile and bleed freely when scab is scraped away.
 Contains phagocytes and get rid of the blood clot
and connective tissue cells that make collagen fibers
that permanently bridge the gap.
– While all this is going on, epithelium grows
back together covering the scar tissue.

38. VIII. Tissue Repair
 The scar is either invisible or visible
depending on the severity of the wound
 Epithelial tissues such as skin and mucous
membranes regenerate beautifully as do
most of the fibrous connective tissue and
bone.
 Skeletal muscles regenerate poorly, if at all,
and cardiac muscle and nervous tissue are
replaced only by scar tissue.

39. VIII. Tissue Repair
 Scar tissue is strong, but lacks flexibility.
 It cannot perform the normal functions of
the tissue it replaces.
 If scar tissue forms in the wall of the
bladder, heart, or other muscular organ, it
may SEVERELY hamper the functioning
of that organ.

40. IX. Developmental Aspects of
Tissues
 Know some stages of aging (pg 86)
 Neoplasm – Then cells multiply wildly an
an abnormal mass of proliferating cells
results. Can be either benign or malignant.
 Hyperplasia – Normal increase in certain
body tissues or organs
 Atrophy – decrease in the size of an organ
due to non-use.