1. 4
Tissue: The Living Fabric: Part B

2. Cells in Tissues can be spaced differently
Epithelial tissue cells are packed close together, with only a small amount of fluid between them.
Many connective tissue cells are spaced further apart, with a gooey substance between them
Other connective tissue cells also have fibers within the gooey substance.

3. CONNECTIVE TISSUES CELLS secrete gel and fibers
protein fiber
INTRAcellular fluid
Ground substance:
A name for all extra
fluid, gel,or minerals
between cells
*Matrix = Ground Substance PLUS fibers

4. Many types of cell are found in CT
Each CT has its own cell types with a particular function:
Adipose CT has adipocytes store fat
Blood CT has erythrocytes which carry oxygen
Areolar CT has fibroblasts which make fibers
Cartilage CT has chondroblasts which make fibers,
NOTE:
Cyte = mature cell
Blast= cell that can still develop into a cyte, and usually make fibers

5. Around the cells are:
Ground substance: a sugary complex (hyaluronic acid and proteoglycan) that traps water and nutrients near the cells to keep them hydrated.

6. Around the cells are: 2. Protein fibers such as
-Collagen fibers (made of collagen)
Strongest and most common fiber
-Elastic fibers (made of elastin)
allow for stretch
-Reticular fibers (made of collagen)
Short, fine, highly branched fibers

7. Let’s learn the specific connective tissues!
AREOLAR CT
ADIPOSE CT
BLOOD CT
DENSE REGULAR CT
DENSE IRREGULAR CT
ELASTIC CT
HYALINE CARTILAGE CT
ELASTIC CARTILAGE CT
FIBROCARTILAGE CT
OSSEOUS CT
COMPACT
SPONGY
RETICULAR CT

8. AREOLAR CONNECTIVE TISSUE
(a) Connective tissue proper: loose connective tissue, areolar
Description: Gel-like matrix with all
three fiber types; cells: fibroblasts,
macrophages, mast cells, and some
white blood cells.
Elastic
fibers
Function: Wraps and cushions
organs; its macrophages phagocytize
bacteria; plays important role in
inflammation; holds and conveys
tissue fluid.
Collagen
fibers
Location: Widely distributed under
epithelia of body, e.g., forms lamina
propria of mucous membranes;
packages organs; surrounds
capillaries.
Fibroblast
nuclei
Epithelium
Photomicrograph: Areolar connective tissue, a
soft packaging tissue of the body (300x).
Lamina
propria
Figure 4.8a

9. Areolar CT cartoon Cell types Extracellular matrix Ground substance
Macrophage
Fibers
• Collagen fiber
• Elastic fiber
• Reticular fiber
Fibroblast
Lymphocyte
Fat cell
Capillary
Mast cell
Neutrophil
Figure 4.7

10. Areolar Connective Tissue
Location: surrounds blood vessels, nerves, and muscles.
Functions: cushions organs, and provides an immune defense
Cells: fibroblasts, macrophages, leukocytes, plasma cells, mast cells, and adipocytes
Matrix elastic fibers, collagen fibers, reticular fibers, and gel

11. ADIPOSE CONNECTIVE TISSUE
(b) Connective tissue proper: loose connective tissue, adipose
Description: Matrix as in areolar,
but very sparse; closely packed
adipocytes, or fat cells, have
nucleus pushed to the side by large
fat droplet.
Function: Provides reserve food
fuel; insulates against heat loss;
supports and protects organs.
Nucleus of
fat cell
Location: Under skin in the
hypodermis; around kidneys and
eyeballs; within abdomen; in breasts.
Adipose
tissue
Vacuole
containing
fat droplet
Photomicrograph: Adipose tissue from the
subcutaneous layer under the skin (350x).
Mammary
glands
Figure 4.8b

12. Adipose Connective Tissue
Location here: Hypodermis (below skin)
Function: energy storage, insulation and protective cushioning
Cells: adipocytes
No matrix.

13. BLOOD CONNECTIVE TISSUE
(k) Others: blood
Description: Red and white
blood cells in a fluid matrix
(plasma).
Plasma
Function: Transport of
respiratory gases, nutrients,
wastes, and other substances.
Type of
leukocyte
Location: Contained within
blood vessels.
Erythrocytes
Type of
leukocyte
Photomicrograph: Smear of human blood (1860x); two
white blood cells (neutrophil in upper left and lymphocyte
in lower right) are seen surrounded by red blood cells.
Figure 4.8k

14. Blood Connective Tissue
Location: inside blood vessels
Cells: erythrocytes, leukocytes
Function: carries fluid, gas, nutrients, wastes and hormones
Matrix: plasma and fibrin (does not form fibers unless exposed to air)

15. Bloody Case Study
Daryl is a 2 year old male who recently moved with his family from Florida to Wisconsin. Playing in the snow for his first time he becomes increasingly cranky and will not stop crying. He seems to have pain, fever, and rapid heart rate. His parents tell the ER nurse they think he may be developing the flu.
Your job: compare his blood work (below) with normal blood work (above). Write down BOTH similarities and difference in what you see.

16. DENSE REGULAR CONNECTIVE TISSUE
(d) Connective tissue proper: dense connective tissue, dense regular
Description: Primarily parallel
collagen fibers; a few elastic fibers;
major cell type is the fibroblast.
Collagen
fibers
Function: Attaches muscles to
bones or to muscles; attaches bones
to bones; withstands great tensile
stress when pulling force is applied
in one direction.
Location: Tendons, most
ligaments, aponeuroses.
Nuclei of
fibroblasts
Shoulder
joint
Ligament
Photomicrograph: Dense regular connective
tissue from a tendon (500x).
Tendon
Figure 4.8d

17. Dense Regular Connective Tissue
Location: tendons and ligaments
Function: strong rope connects muscle to bone, or bone to bone
Cells: Fibroblasts
Matrix: collagen fibers and gel

18. DENSE IRREGULAR CONNECTIVE TISSUE
(e) Connective tissue proper: dense connective tissue, dense irregular
Description: Primarily
irregularly arranged collagen
fibers; some elastic fibers;
major cell type is the fibroblast.
Nuclei of
fibroblasts
Function: Able to withstand
tension exerted in many
directions; provides structural
strength.
Location: Fibrous capsules of
organs and of joints; dermis of
the skin; submucosa of
digestive tract.
Collagen
fibers
Fibrous
joint
capsule
Photomicrograph: Dense irregular
connective tissue from the dermis of the
skin (400x).
Figure 4.8e

19. Dense Irregular Connective Tissue
Location: dermis of skin, around organs.
Function: Strong net “covering” for organs
Cells: Fibroblasts
Matrix: collagen fibers and gel

20. The major difference between Dense Regular and Dense Irregular CT is:
The type of protein fibers in each
The cell types in each
The orientation of the fibers
The color it stains

21. (f) Connective tissue proper: dense connective tissue, elastic
Description: Dense regular
connective tissue containing a high
proportion of elastic fibers.
Function: Allows recoil of tissue
following stretching; maintains
pulsatile flow of blood through
arteries; aids passive recoil of lungs
following inspiration.
Elastic fibers
Location: Walls of large arteries;
within certain ligaments associated
with the vertebral column; within the
walls of the bronchial tubes.
Aorta
Photomicrograph: Elastic connective tissue in
the wall of the aorta (250x).
Heart
Figure 4.8f

22. Elastic Connective Tissue
Location: Within artery walls
Function: provides elasticity within arteries
Cells: Fibroblasts
Matrix: elastic fibers and gel

23. This is elastic tissue in the aorta
This is elastic tissue in the aorta. What is happening in Marfan syndrome?

24. Fibrotic tumors Aortic aneurisms Auto immune disease Dwarfism
Which of the following is a possibly fatal complication for patients with Marfan’s Syndrome?
Fibrotic tumors
Aortic aneurisms
Auto immune disease
Dwarfism

25. (g) Cartilage: hyaline
Description: Amorphous but firm
matrix; collagen fibers form an
imperceptible network; chondroblasts
produce the matrix and when mature
(chondrocytes) lie in lacunae.
Function: Supports and reinforces;
has resilient cushioning properties;
resists compressive stress.
Location: Forms most of the
embryonic skeleton; covers the ends
of long bones in joint cavities; forms
costal cartilages of the ribs; cartilages
of the nose, trachea, and larynx.
Chondrocyte
in lacuna
Matrix
Costal
cartilages
Photomicrograph: Hyaline cartilage from the
trachea (750x).
Figure 4.8g

26. Hyaline Connective Tissue
Location: ends of some bones, trachea, ribs, and nose
Function: protects bone ends and airway
Cells: chondroblasts, and chondrocytes
Matrix: Collagen fibers and gel

27. ELASTIC CARTILAGE CONNECTIVE TISSUE
(h) Cartilage: elastic
Description: Similar to hyaline
cartilage, but more elastic fibers
in matrix.
Function: Maintains the shape
of a structure while allowing
great flexibility.
Chondrocyte
in lacuna
Location: Supports the external
ear (pinna); epiglottis.
Matrix
Photomicrograph: Elastic cartilage from
the human ear pinna; forms the flexible
skeleton of the ear (800x).
Figure 4.8h

28. Elastic Cartilage Connective Tissue
Location: outer ear, epiglottis, auditory canal
Function: flexible strong mesh
Cells: chondroblasts, chondrocytes
Matrix: elastic fibers and gel

29. FIBROCARTILAGE CONNECTIVE TISSUE
(i) Cartilage: fibrocartilage
Description: Matrix similar to
but less firm than that in hyaline
cartilage; thick collagen fibers
predominate.
Function: Tensile strength
with the ability to absorb
compressive shock.
Location: Intervertebral discs;
pubic symphysis; discs of knee
joint.
Chondrocytes
in lacunae
Intervertebral
discs
Collagen
fiber
Photomicrograph: Fibrocartilage of an
intervertebral disc (125x). Special staining
produced the blue color seen.
Figure 4.8i

30. Fibrocartilage Connective Tissue
Location: intervetebral discs, pubic symphysis, meniscus pad in knee joint
Function: cushions shock to bones
Cells: chondroblasts, chondrocytes
Matrix: collagen fibers and gel

31. Which of the following is NOT true concerning cartilage connective tissue
Hyaline cartilage contains collagen fibers
Elastic cartilage contains elastic fibers
Fibrocartilage contains collagen fibers
All of the above are true

32. COMPACT OSSEOUS CONNECTIVE TISSUE
(j) Others: bone (osseous tissue)
Description: Hard, calcified
matrix containing many collagen
fibers; osteocytes lie in lacunae.
Very well vascularized.
Central
canal
Function: Bone supports and
protects (by enclosing);
provides levers for the muscles
to act on; stores calcium and
other minerals and fat; marrow
inside bones is the site for blood
cell formation (hematopoiesis).
Lacunae
Lamella
Location: Bones
Photomicrograph: Cross-sectional view
of bone (125x).
Figure 4.8j

33. Compact Osseous Connective Tissue
Location: outer hard portion of bones.
Cells: osteoblasts, osteocytes, osteoclasts,
Function: Strong structures
Matrix: collagen fibers, calcium and phosphate mineral

34. SPONGY OSSEOUS CONNECTIVE TISSUE
osteocyte
Blood cells
osteoblasts

35. Spongy Osseous Connective Tissue
Location: softer bony structure inside the heads of the long bones
Function: ability to compress, lightweight
Cells: osteoblasts, osteocytes, osteoclasts
Matrix: collagen fibers, calcium and phosphate minerals

36. Which of the following is true about osseous connective tissue?
Osteoblasts reside in lacunae
Osteocytes make the bone tissue
Osteoclasts destroy bone tissue
All of the above are true
None of the above are true

37. RETICULAR CONNECTIVE TISSUE
(c) Connective tissue proper: loose connective tissue, reticular
Description: Network of reticular
fibers in a typical loose ground
substance; reticular cells lie on the
network.
Function: Fibers form a soft internal
skeleton (stroma) that supports other
cell types including white blood cells,
mast cells, and macrophages.
White blood
cell
(lymphocyte)
Location: Lymphoid organs (lymph
nodes, bone marrow, and spleen).
Reticular
fibers
Spleen
Photomicrograph: Dark-staining network of reticular
connective tissue fibers forming the internal skeleton
of the spleen (350x).
Figure 4.8c

38. Reticular Connective Tissue
Location: lymph nodes and spleen
Cells: fibroblasts, leukocytes
Function: forms weak structure of lymph nodes, spleen, bone marrow
Matrix: reticular fibers and gel

39. Let’s look at the list of connective tissues again.
Why are they arranged in this order?
AREOLAR CT
ADIPOSE CT
BLOOD CT
DENSE REGULAR CT
DENSE IRREGULAR CT
ELASTIC CT
HYALINE CARTILAGE CT
ELASTIC CARTILAGE CT
FIBROCARTILAGE CT
OSSEOUS CT
COMPACT
SPONGY
RETICULAR CT

40. It is a chocolate chip sea cucumber!
Now that you know all the connective tissues… Can you identify this structure?
Trick question!
It is a chocolate chip sea cucumber!

41. NERVOUS TISSUE Nervous tissue Description: Neurons are
branching cells; cell processes
that may be quite long extend from
the nucleus-containing cell body;
also contributing to nervous tissue
are nonirritable supporting cells
(not illustrated).
Nuclei of
supporting
cells
Neuron processes
Cell body
Axon
Dendrites
Cell body
of a neuron
Function: Transmit electrical
signals from sensory receptors
and to effectors (muscles and
glands) which control their activity.
Neuron
processes
Location: Brain, spinal
cord, and nerves.
Photomicrograph: Neurons (350x)
Figure 4.9

42. Nervous Tissue
Location: spinal cord, brain, organs, skin
Function: sensation, receive info and send out info
Cells: neurons, glial cells

43. The Discovery of Alzheimer’s disease
In 1901, Alois Alzheimer met a confused and anxious patient whose memory was failing. It was not until she died 5 years later that he examined her brain tissue, discovering that the neurons had unusual fibrils inside them, and there were unusual substances, or plaques, between the cells.

44. SKELETAL MUSCLE TISSUE
(a) Skeletal muscle
Description: Long, cylindrical,
multinucleate cells; obvious
striations.
Striations
Function: Voluntary movement;
locomotion; manipulation of the
environment; facial expression;
voluntary control.
Nuclei
Location: In skeletal muscles
attached to bones or
occasionally to skin.
Part of
muscle
fiber (cell)
Photomicrograph: Skeletal muscle (approx. 460x).
Notice the obvious banding pattern and the
fact that these large cells are multinucleate.
Figure 4.10a

45. Skeletal Muscle Tissue
Location: connecting to bones, or in sphincters
Function: voluntary contraction, to pull on bones and close sphincters (contract anus, squint eyes)
Cells: skeletal muscle cells
Nuclei: hundreds in a single cell
Striations (stripes): yes
Shape: cylindrical

46. CARDIAC MUSCLE TISSUE (b) Cardiac muscle Description: Branching,
striated, generally uninucleate
cells that interdigitate at
specialized junctions
(intercalated discs).
Striations
Intercalated
discs
Function: As it contracts, it
propels blood into the
circulation; involuntary control.
Location: The walls of the
heart.
Nucleus
Photomicrograph: Cardiac muscle (500X);
notice the striations, branching of cells, and
the intercalated discs.
Figure 4.10b

47. Function: mainly involuntary contraction, to pump blood
Cardiac Muscle Tissue
Location: heart
Function: mainly involuntary contraction, to pump blood
Cells: cardiac muscle cells
Nuclei: one centrally located nucleus in each cell
Striations: yes
Shape: branched cells shape (like a “Y”)
Special junctions: intercalated discs

48. Chagas disease
Trypanosomiasis is an often fatal disease is caused the protozoan T. cruzi, infecting heart cells.
transmitted through the bite of a “kissing bug”.

49. SMOOTH MUSCLE TISSUE (c) Smooth muscle Description: Spindle-shaped
cells with central nuclei; no
striations; cells arranged
closely to form sheets.
Smooth
muscle
cell
Function: Propels substances
or objects (foodstuffs, urine,
a baby) along internal passage-
ways; involuntary control.
Location: Mostly in the walls
of hollow organs.
Nuclei
Photomicrograph: Sheet of smooth muscle (200x).
Figure 4.10c

50. Smooth Muscle Tissue
Location: around hollow organs (intestine,bladder)
Function: involuntary contraction, to move food, fluid through tubes
Cells: smooth muscle cells
Special characteristics
Nuclei: one centrally located nucleus per cell
Striations: no
Shape: cylindrical, squashed on both ends

51. Muscle cell characteristics
Location
Function
Voluntary?
Cell shape?
One or many
nuclei?
Striated?
Inter-calated
discs?
Smooth
Muscle
cells
Cardiac
Skeletal

52. Membranes
A membrane is one or more thin layers of tissue, (like putting down three flat sheets on a bed.)

53. CUTANEOUS MEMBRANES (the skin) structure: ET, CT, MT layers
! Function: protects your organs
Figure 4.11a

54. Structure: ET and CT layers
Mucosa of
nasal cavity
Mucosa of
mouth
Esophagus
lining
Mucosa of
lung bronchi
(b) MUCOUS MEMBRANES
Structure: ET and CT layers
Function: line body cavities that open to the outside of the body
MAY secrete mucous (as in nose and trachea)
or may NOT (mouth/lungs)
Figure 4.11b

55. Structure: ET and CT, secrete slippery serous fluid
(c) SEROUS MEMEBRANES
Structure: ET and CT, secrete slippery serous fluid
Function: line body cavities closed to the exterior (lungs)
Parietal
peritoneum
Parietal
pleura
Visceral
pleura
Visceral
peritoneum
Parietal
pericardium
Visceral
pericardium
Figure 4.11c

56. Why don’t we call these be membranes?