Epithelial Tissue

1

• Epithelial Tissue
• Simple Squamous
• Epithelial Tissue
• One layer of flattened cells
• Little intercellular space
• Avascular
• Note purple, round nucleus with dark nucleolus
  and light staining cytoplasm. Cell membrane is
  pink.

2

• Epithelial Tissue
• Simple Squamous
• Epithelial Tissue
• (buccal smear)
• Simple squamous epithelial cells from the human
  mouth
• Lines blood vessels, body cavities, comprises the
  pericardium and pleura, and forms part of the
  mesentery

3

• Epithelial Tissue Simple Squamous (buccal smear)

Note the round, pink nucleus, light staining
cytoplasm, and flattened shape.
4

• Epithelial Tissue
• Simple Cuboidal
• Epithelium
• (kidney epithelium)
• Red arrows indicate simple cuboidal epithelium.
• Green arrows indicate simple squamous epithelium.
• Covers ovary and thyroid in addition to forming
  kidney tubules

5

• Epithelial Tissue
• Simple Cuboidal
• Epithelium
• (kidney epithelium)
• Simple cuboidal epithelium (red arrows) comprises
  the single-celled-thick walls of the tubules.
  These cells are square shaped with centrally
  located, round nuclei.
• Simple squamous epithelium (green arrows) forms
  the outer layer of Bowmans capsules

6

• Epithelial Tissue
• Simple Columnar
• Epithelium
• amphibian intestine (cs)
• The villi serve to greatly increase the surface
  area.
• Functions in protection, lubrication, digestion,
  absorption, and secretion
• One cell layer of epithelium
• Lines the intestines and gall bladder

Epithelial layer
7

• Epithelial Tissue
• Simple Columnar
• Epithelium
• amphibian intestine (cs)
• Note that cells are taller than they are wide,
  have oval shaped nuclei at the basal portion of
  the cell
• Blue arrow indicates the lumen of intestine
• Red arrow indicates the brush border (microvilli)
• Green arrow indicates a goblet cell

8

• Epithelial Tissue
• Pseudostratified Columnar Epithelium
• trachea (cs)
• Green arrow indicates Pseudostratified Columnar
  Epithelium
• Found on the surface of the trachea, brochi, and
  nasal cavity

9

• Epithelial Tissue
• Pseudostratified Columnar Epithelium
• Note There are 2 rows of nuclei (bracket).
  However, all cells contact the basement membrane
  (hence pseudostratified)
• Tall cells reach the lumen, short cells do not.
• Green arrow indicates goblet cell
• Blue arrow indicates cilia

10

• Epithelial Tissue
• Stratified Squamous Epithelium
• Outer layer of skin (keratinized or dry)
• Mouth, esophagus, vagina, and anal canal
  (non-keratinized)
• Epithelial layer indicated by line (also called
  epidermis)
• Many layers of cells, but only the bottom cell
  layer contacts the basement membrane
• Red arrow indicates glandular epithelium

11

• Epithelial Tissue
• Transitional Epithelium
• (indicated by line/arrow)
• Transitional epithelium is a stratified type
  that can be confused with stratified squamous.
   The name transitional comes from the ability of
  this epithelium to accommodate stretching in the
  urinary tract as fluid pressures vary.  It is
  only found as a lining of the ureters, urethra,
  and bladder.  

12

• Epithelial Tissue
• Transitional Epithelium
• Mixture of squamous, cubodial, and columnar
  epithelial layers
• The identifying feature is the domed appearance
  of the surface cells when the tissue is relaxed.
• Cell types are distinguished by the shapes of the
  nuclei
• Green arrow squamous
• Red arrow cuboidal
• Blue arrow columnar

13

• Connective Tissue
• Connective Tissue Proper
• Loose Connective Tissue
• Note presence of fibers creating web-like mesh,
  numerous cells (fibroblast nuclei) separated by
  space
• Avascular-no direct vascular supply. However
  blood vessels pass through the tissue (red arrow)
• Green arrow Elastic fiber
• Thick, faint lines represent poorly staining
  collagen fibers

14
Loose connective tissue proper
15

• Connective Tissue
• Connective Tissue Proper
• Loose Connective Tissue
• Outer layer of most organs
• Supports the epithelium of glands and wet
  membranes
• Green arrow indicates elastic fiber
• Blue arrow indicates fibroblast nucleus (large
  light staining)
• Red arrow indicates macrophage nucleus (small
  darker staining)

16

• Connective Tissue
• Connective Tissue Proper
• Dense Irregular
• Connective Tissue
• (single line)
• Darker staining than loose CT (more collagen
  fibers, irregularly arranged)
• Dermis of skin and outer capsule surrounding most
  organs
• Loose connective tissue indicated by double line
• Epidermis (triple line) is composed of stratified
  squamous epithelium

epidermis
dermis
mammalian esophagus
17

• Connective Tissue
• Connective Tissue Proper
• Dense Regular
• Connective Tissue
• Note regularly arranged lines of collagen fibers
  (pink)
• Fibroblast nuclei (purple stain) are always
  flattened
• Tendons and ligaments

Tendon
18

• Connective Tissue
• CT with Special Properties
• Blood (frog)
• Pink cells are erythrocytes (red blood cells)
• RBCs contain nuclei in amphibians
• Note the lack of visible fibers

19

• Connective Tissue
• CT with Special Properties
• Blood (mammalian)
• Pink cells are erythrocytes (mammalian RBC lack
  nuclei)
• Green arrows indicate leukocytes
• Note lack of visible fibers

20

• Connective Tissue
• CT with Special Properties
• Blood (mammalian)
• Erythrocytes are biconcave disks
• Green arrows indicate leukocytes
• Red arrows indicate platelets (small cell
  fragments). Function in clot formation

21

• Connective Tissue
• CT with Special Properties
• Adipose Tissue
• Cells look empty (fat has been extracted from
  cell during processing)
• Cytoplasm and nuclei pushed to periphery of cell
  by lipid
• Green arrow vein
• Red arrow artery

22
Trachea

• Connective Tissue
• Supporting
• Connective Tissue
• Cartilage
• Hyaline cartilage indicated by line
• Green arrows indicate perichondrium (dense
  irregular connective tissue)
• Red arrow indicates pseudostratified columnar
  epithelium
• Blue arrow indicates loose connective tissue
• Purple arrow indicates glandular epithelium

23
(No Transcript)
24

• Connective Tissue
• Supporting Connective Tissue
• Bone
• Compact bone (outer portion of long bones)
• Spongy bone (inner regions and at end of long
  bones)
• Hard matrix of hydroxyapatite and collagen fibers

Compact bone
25

• Connective Tissue
• Supporting Connective Tissue
• Compact Bone
• Compact bone
• Green arrow and circle indicates circular array
  of osteocytes in lacunae (Haversian System or
  Osteon)
• Red arrow indicates lacunae (oval, black dots)

26
(No Transcript)
27

• Muscle Tissue
• Smooth Muscle
• 2 layers of smooth muscle denoted by line
• Gastrointestinal tract, respiratory tract, blood
  vessels, uterus, bladder, and skin
• Inner layer of circular
• Outer layer of longitudinal
• Green arrow simple columnar epithelium
• Red arrow adipose
• Black arrow thin ring of smooth muscle tissue
  (both circular and longitudinal)
• Blue arrow loose connective tissue

Monkey colon (cs)
L
C
28

• Muscle Tissue
• Striated
• Skeletal Muscle
• Line indicates individual muscle cell called a
  muscle fiber
• Cells are syncytial
• Note striations due to arangement of thick and
  thin flaments
• Note multiple, oval nuclei at periphery per cell
  (arrows)

29

• Muscle Tissue
• Striated Skeletal Muscle
• Line indicates individual muscle cell muscle
  fiber
• Note striations and bands
• Note multiple, oval nuclei at the periphery of
  each cell
• voluntary

30

• Muscle Tissue
• Striated Cardiac Muscle
• Note striations/bands
• Cells are branched and shorter than striated
  skeletal muscle cells
• Multinucleate but centrally located and far fewer
  in number
• Syncytial
• Intercalated disks with gap junctions permit
  rapid intercellular communication
• Involuntary

31

• Muscle Tissue
• Striated Cardiac Muscle
• Note a few centrally located nuclei
• Intercalated discs (green arrows)
• Cells are syncytial and branched

32

• Nervous Tissue
• Peripheral nerves
• Neuron functional unit of nervous tissue
  (perikaryon is denoted by the green arrow)
• Glial cells supporting insulating cells of
  nervous tissue (small purple dots are glial cell
  nuclei)

33

• Nervous Tissue
• Neuron-functional unit of nervous tissue
• Perikaryon-cell body (green arrow) contains the
  nucleus and most of the organelles
• Axon conducts impulses away from the cell body
• Dendrites transmit impulses to the perikaryon
• Glial cells-supporting cells of the nervous
  tissue wrap around the axons hundreds of times to
  provide insulation
• Small purple dots (red arrows) are the glial cell
  nuclei

34
Nervous Tissue Another image of a neuron. Name
the sundry components
35
Nervous Tissue Peripheral nerves Two bundles
(fascicles) of nerve fibers are visible in this
transverse section. The perineurium (green
arrow) is a shealth of connective tissue which
merges with interfasicular connective
tissue Clearly visible are cross sectional and
longitudinal views of myelinated axons. Glial
cells (myelin sheaths) are unstained and axons
are the central pink dots in the cross sections.
36
An enlarged view of the previous slide.
37
Nervous Tissue Peripheral nerves Magnified
longitudinal view of a fascicle. Glial cell
(green arrow) forming the myelin sheath Axon (red
arrow) Internode (blue bracket) Node of Ranvier
(black arrow)
38
Nervous Tissue Central Nervous System (mammal
spinal cord) The central nervous system is
composed of white matter and gray matter. White
matter is so named because the preponderance of
myelinated axons gives the tissue a white
appearance. Gray matter contains perikaryons
(less lipid) and appears darker. Gray matter
lies in the interior of the spinal
cord.
39
Nervous Tissue Central Nervous System (mammal
spinal cord)
40
Nervous Tissue Central Nervous System
(monkey cerebellum)
In the brain, the gray matter lies on the outside