The document summarizes the four major types of tissues in the body: epithelial, connective, muscular, and nervous tissue. It provides detailed information on the structure and function of each type of tissue. Epithelial tissue forms protective layers and linings. Connective tissue includes bone, cartilage, blood, and adipose tissue that support and bind other tissues. Muscular tissue, including cardiac, smooth and skeletal muscle, allows movement. Nervous tissue is specialized for conducting electrical signals and is found in the brain, spinal cord and nerves.

1. TISSUES
Mohammed Hasan Alhakari

2. Tissue
- is a group of similar cells specialized
for the performance of a common
function.
- The study of tissues is called Histology
- the cells in multicellular animal maybe
divided into 2. Somatic cells or body
cells and Germ cells, having to do only
with reproduction and continuance of species.

4. There are 4 major groups of somatic
tissues, and these are:
1. Epithelial Tissues
2. Connective Tissues
3. Muscular Tissues
4. Nervous Tissues

5. Epithelial Tissues
- form the covering or lining of all free body
surfaces, both external and internal.
- consists of renewable sheets of cells
- supported by basement membrane which
separates epithelial tissues from underlying,
adjacent tissues.

6. Functions of Epithelial Tissue:
1. Absorb (the lining of the small intestine)
2. Transport ( kidney tubules)
3. Excrete ( sweat glands)
4. Protect ( skin )
5. Contain nerve cells for sensory reception
(taste buds in the tongue)

7. Structures of Epithelial Tissues:
Layers:
1. Simple – consisting of only one layer of cells.
2. Stratified – consisting multiple slacked layers
3. Pseudostratified ciliated columnar epithilium
- possess cilia and appears layered but not.
- appears layered because of their nuclei are at two
or more levels within the cell of the tissue.

8. Shapes:
1. Squamous Epithelium or flat
2. Cuboidal Epithelium or cube shaped
3. Columnar Epithelium or column like

9. Squamous Epithelium

10. Simple Cuboidal Epithelium Lining

11. Columnar Epithelium Cells

12. Connective Tissue
- binds together and supports other
structures
- divided throughout an extracellular matrix
- derived from the Mesenchyme, a
generalized embryonic tissue that can
differentiate also into vascular and smooth
muscle. (also considered the most primitive
connective tissue)

13. Two General Types of Connecticve
Tissues
1. Loose Connective Tissue
- strong, flexible fibers of protein collagen are interwoven
with fine elastic, and reticular fibers giving it its elastic
consistency and making it an exellent binding tissue.
2. Fibrous Connective Tissue
- the collagen fibers are densly packed and may lie parallel to
one another, creating very strong cords, such as tendons and
ligaments.

14. Kinds of Connective Tissues
1. Adipose Tissue
- is a type of loose connective that consists of large cells that
store lipids.
- consists scattered, rounded or branched in form, with
intercellular spaces occupied by delicate fibers.
- also known as fat tissues
- cells accumulate in large numbers to form what is commonly
known as fat.
- Two minor cell types are present; fibroblasts, which produce
fibers, and macrophages, which are phagocytes.

15. Adipose Tissue

16. 2. Cartilage
-is a firm yet elastic matrix (chondrin) secreted by small
groups of rounded cartilage cells or Chondrocytes
embedded within it and covered by a thin, fibrous
Perichondrium.
- Is a hard yet flexible tissue that supports such structures
as the outer ear and forms the entire skeleton of such
animals as sharks and rays.
- Cells called Chondrocytes lie within spaces called
Lacunae that are sorrounded by a rubbery matrix that
chomdroblasts secrete.
- the matrix gives the cartilage its strength and elasticity.

17. Cartilage

18. 3. Bone or Osseous Tissue
- Like other connective tissues, bone consists of cells,
fibers and ground substance but differs because the extracellular
matrix is calcified.
- the rigid extracellular matrix has several functions
* Provides an internal support for the body and
attachment for muscles and tendons.
* Protects vital organs of the cranial and thoracic
cavity, and encloses the blood forming elements of the bone
marrow.
* Provides a reservvoir of ionic calcium essential
for many cellular processes of the body.

19. Macroscopic Structure of the Bone
A. Diaphysis: shaft of the bone
B. Epiphysis: end of a long bone
C. Metaphysis: area between the diaphysis and the epiphysis
D. Epiphyseal plate (growth plate)
E. Medullary Cavity: central cavity of bone occupied by bone
marrow
F. Trabeculae: irregular lattice of thin columns of bone
sorrounded by bone marrow
G. Articular Cartilage: Hyaline cartilage covering joint surfaces
H. Periosteum: external covering of bone
I. Endosteum: internal covering of bone

20. Bone Cells
A. Osteoprogenitor Cell
1. A mesenchymeal sterm cell that can undergo mitotic
division and differentiate into an osteoblast.
2. Osteoprogenitor calls are located on the immer cellular
layer of the periosteum, the endosteum and lining osteonic
canals.
3. These calls are most active during bone growth, but large
numbers are reactivated in adult life in repair of fractures.
4. They also differentiate into osteoblasts during the
continous process of bone remodeling

21. B. Osteoblasts
1. Cells that are derived from osteoprogenitor cellas and
are responsible for the synthesis of the organic components of
bonw matrix, which is called osteoid.
2. They are located on the surface of bone tissue and
resemble epithelium. When the cells are active they have a
cuboidal appearance; and when their activity declines, they
flatten
3. They have the structure expected of cells that are
actively engaged on protein synthesis, such as extensive rough
ER, well developed Golgi complex and numerous secretory
vesicles.
4. The cells have cytoplasmic processes that bring them in
contact with neighboring cells.

22. D. Osteocytes
1. When osteoblast has completely sorrounded itself and
its cytoplasmic processes with matrix, the cell is now termed an
osteocyte.
2. The space on which the cell resides os termed lacuna.
The thin cylindrical spaces that house cytoplasmic processes are
called canaliculi. Canaliculi also contain extracellular fluid
carrying nutrients to nourish osteocytes.
3. Processes of adjacent cells make contact via gap
junctions, which allow ions and small molecules to travel from
cell to cell.

23. D. Osteoclasts
1. Large, motile, multinucleated, bone-resorbing cells
derived from blood monocytes that occupy depressions in the
bone matrix undergoing active resorption.
2. Adhere tightly to established bone matrix and acidify
the surface by the use of a proton pump that actively transports H
ionsonto the surface of the bone. Lysosomal enzymes are
released by exocytosis and degrade the organic components of
bone.
3. The degraded minerals on organic components are
endocytosed by the osteoclast and delivered to nearby capillaries
to enter the circulation.

24. Bone Coverings
A. Periosteum:
1. The external covering of bone, except in areas where
tendons and ligaments insert into bone and on the surfaces
covered by articular cartilage.
2. Consists of 2 layers
a. Outer fibrous layer – collagenous connective tissue that
contains many blood vessels.
b. Inner Cellular Layer – layer that contains
osteoprogenitor cells that have osteogenic potential
3. Sharpey’s Fibers: Bundles of periostal collgen fibers that
penetrate the bone matrix and strongly adheres the periosteum to
bone.

25. B. Endosteum
-Thin layer of osteoprogenitor cells, osteoblasts and a
small amount of connective tissue that lines all internal surfaces
of cavities within bone including the osteonic canals and marrow
spaces.

26. One or Osseous Tissue (Haversian Canal)

27. 4. Blood
- is a connectie tissue in which a fluid called plasma
suspends specialized re and white blood cells plus platelets.
- a viscous fluid pumped all throughout the body
- mesoderm in origin
- transports various substances throughout the bodies of
animals.
- Erythrocytes (Red Blood Cells)
- composed of cells, fibers and amorphous ground
substance.

28. Functions:
1. Carry oxygen and nutrients to the cell and carry waste
materials – CO2 away from the cells to kidneys and lungs.
2. Immune System
3. Homeostasis in the body.
Ground Substance/Matrix:
- fluid and protein in the plasma
Albumin = are to maintain the osmotic
pressure of the blood.

29. Cells:
1. Erythrocytes (RBC)
2. Leukocytes (WBC)
3. Thrombocytes/ blood platelets
Fibers:
- these are the potential fibers of fibrinogen which are
converted to fibrils fiber during blood clotting.
- Clotted solid. Which rapidly stops blood flow from the
wound.
Note - blood clots occur when platelets interact with and
respond to collagen fibers that they encounter when they leave
the circulaing system in response to a wound.

30. Human Red Blood Cells
Platelets and T-lymphocyte
(Erythocytes = red; platelets = yellow; T-lymphocyte = light green)

31. Red Blood Cells

32. Muscle Tissue
- is the driving force, the power behind movement in most
vertebrates and invertebrates.
- specialized for contractility
- most common tissue in the body of most animals.
- made of elongated cells made for contraction.
- allows movement.
3 Important Properties of Muscle Tissue
1. Excitability (or irritability)- the capacity to receive and
respond stimulus.
2. Extensibility –the ability to be stretched
3. Elasticity –the ability to return to its original shape
after being stretche or contracted.

33. 3 kinds of muscle Tissue
1. Smooth Muscle (or unstriated involuntary)
2. Skeletal Muscle (or striated voluntary)
3. Cardiac Muscle (or striated involuntary)

34. Smooth Muscle
- is formed of spindle –shaped cells, each containing a
single nucleus
- cells are arranged closely to form sheets
- not striated
- mostly found in the walls of hollow organs
- are organized into sheets of muscle circling the wall of
the alimentary canal, blood vessels, respiratiry passages,
and urinary and genital ducts.
- moves substances or objects( foodstuffs, urine, baby)
along internal passageways
- also called involuntary muscle because higher brain
centers do not control its contractions.

35. Smooth Muscle Tissue

36. Skeletal Muscle
-is composed of striated muscle fibers (cells) containing
many peripheral nuclei.
- are those attached to the skeleton and are typically
organized into sturdy, compact bundles or bands.
- extremely long, cylindrical, multinucleate cells that may
reach from one end of the muscle to the other.
- the characteristic light and dark bands(striations)
represents the fine structure of the myofibrils that make up the
fibers.
- a.k.a. voluntary muscle because nercous system
consciously controls its contractions.
- for voluntary movement or locomotion

37. Skeletal Muscle

38. Cardiac Muscle
- is the muscle of the vertebrate heart
- consists of closely opposed, but separate, uninucleate cell
fibers that appear branching and interconnected.
- contains specialized cell junctions called Interlaced
Disks that allow ions to (action potential) to move quikly
from cell to cell.
- can be found in the walls of the heart
- as the walls of the heart contract, cardiac muscle tissue
propels blood onto the circulation; involuntary control.

39. Striated Muscle Fibers
Heart Muscle Cell
(nucleus, mitochondria, actin-myosin)

40. Heart Muscle Tissue

41. Nervous Tissue
- is composed of several different types of cells:
- is highly specialized for the property of irritability and
conductivity.
- can be found in the brain, spinal cord, and nerves.
- transmits electrical signals from sensory receptors to the
spinal cord or brain, and from the spinal cord or brain to
effectors(muscles and glands)
Nerve – group of fibers or process bound together by a
connective tissue.

42. Neurons
- Impulse conducting cells
- Structural and functional unit of the nervous system.
- arranged in chains
Synapse – point of contact between neurons
Dendrite – the process that transmits stimuli to the cell
body
Axon – carries impulses away from the cell body
Bipolar cells – one dendrite and one axon
Multipolar Cells – multiple dendrites and single axon
Ganglion – a group of nerve cell bodies, with their
conspicuous nuclei when outside the central nervous system.

43. Neuroglia
- cells involved with protection and, support, and
nourishment
- serve as delicate packing to hold neurons apart and may
also aid in nutrition of neurons.
*Nerve fibers are sheathed by special cells called Schwann Cells.
*Nodes of Ranvier- marks the end of the Schwann call and the
beginning of another.
Peripheral Glial Cells
- cells that form sheaths and help protect, nourish,
and maintain the peripheral nervous system.

44. Organization of a Neuron

45. Large Multi-polar Neuron

46. Pyramidal Neurons