Download Tissues

Tissues
Introduction
• Cells are arranged in organized groups
called tissues
• Each type of tissue has its own special
function
Types of Tissue
• There are four basic types of tissue
(1) Epithelium
(2) Connective
(3) Muscular
(4) Nervous
1
Epithelial Tissue
• There are two basic types of epithelium
(1) Covering and lining epithelium
(2) Glandular epithelium
Covering and lining epithelium
• Forms the outer covering of:
- external body surfaces (like the skin)
- some internal organs (like the stomach)
Lines body cavities
Lines the interiors of:
- respiratory and gastrointestinal tract
- blood vessels, ducts
- Hollow reproductive organs (like the uterus)
Glandular Epithelium
• Makes up the secreting portion of glands
2
The Basement membrane
• All epithelium adheres to a connective
tissue membrane layer referred to as the
basement membrane
• The basement membrane attaches the
epithelium to the underlying connective
tissue
The flow chart below illustrates the
different types of epithelial tissue
3
Simple Squamous Epithelium
• Consists of a single layer of flat cells
Description: Looks like a platter of fried eggs
“sunny-side up”
Location: Air sacs (alveoli) of lungs, lines the
inside of heart and blood vessels
Function: Filtration, diffusion, osmosis
Drawing of Simple Squamous
Epithelium
Light Micrograph of Simple
Squamous Epithelium (Superior
aspect)
4
Light micrograph of Simple
Squamous Epithelium (Lateral
aspect)
Simple Cuboidal Epithelium
Description: Consists of a single layer of
cube-shaped cells
Location: Lines kidney tubules and the small
ducts of many glands
Function: Secretion and absorption
Drawing of Simple Cuboidal
Epithelium
5
Light micrograph of Simple
Cuboidal Epithelium
Simple Columnar Epithelium
Description: A single layer of tall rectangular
cells
Location: Lines the gall-bladder and most of
the gastrointestinal tract
Function: Absorption and secretion
Photomicrograph of Simple
Columnar Epithelium
6
Stratified Squamous Epithelium
Description: Many layers of cells with
squamous shaped cells located next to the
lumen (light)
Location: Keratinized variety on palms of
hands and soles of feet
Nonkeratinized variety lines the
mouth, vagina, and esophagus
Function: Protection
Drawing of Stratified Squamous
Epithelium
Photomicrograph of Stratified
Squamous Epithelium (Nonkeratinized)
7
Photomicrograph of Stratified
Squamous Epithelium (Keratinized)
Pseudostratified Ciliated Columnar
Epithelium
Description: Looks like a stratified tissue but
is not. Each cell extends from the
basement membrane to the lumen
Location: Lines the upper respiratory tract
Function: Secretion and movement of
mucous by ciliary action
Photomicrograph of
Pseudostratified Ciliated Columnar
Epithelium
8
Transitional Epithelium
Description: The appearance can vary
greatly, that is why it is called transitional
Location: Lines the urinary bladder and
ureter
Function: Permits distention (stretching)
Drawing of Transitional Epithelium
Photomicrograph of Transitional
Epithelium
9
Connective Tissue
• The most abundant tissue type in the body
• Most types have a rich blood supply
(except Hyaline Cartilage)
The flow chart below illustrates the
different types of connective tissue
The composition of connective
tissue
•
There are three basic elements found in
connective tissue
(1) Fibers (such as collagen, reticular, and
elastic)
(2) Cells (such as fibroblasts, macrophages,
and adipose)
(3) A ground substance (matrix) that
surrounds the fibers and cells
10
The matrix (ground substance) of
connective tissue
(1) Fluid – as in blood
(2) Semifluid – as in loose connective tissue
(3) Gelatinous – as in mucous connective
tissue
(4) Fibrous – as in dense regular connective
tissue
(5) Calcified – as osseous connective tissue
(bone)
Loose (areolar) Connective Tissue
Description: consists of collagen, elastic,
and reticular fibers; together with several
cell types
Location: Hypodermis, around most body
organs
Function: Loosely binds organs together
Photomicrograph of Loose
Connective Tissue
11
Vascular Connective Tissue
(Blood)
•
Blood is a connective tissue with a fluid
matrix called plasma
• Three basic types of cells are found
suspended in plasma
(1) Erythrocytes
(2) Leukocytes
(3) Thrombocytes
Erythrocytes (Red Blood Cells)
Description: Biconcave cells that are stained
pink. The inner center of the cell is lighter
than the rim
Location: Suspended in blood plasma
Function: Transports respiratory gases
(oxygen and carbon dioxide)
Leukocytes (White Blood Cells)
Description: Stained cells with an obvious
nucleus
Location: Suspended in blood plasma, also
found in lymphatic tissues
Function: Involved in immunity
12
Thrombocytes (Platelets)
Description: Small darkly stained structures
Location: Suspended in blood plasma
Function: Involved in blood clotting
Adipose Connective Tissue
Description: Resembles a chicken-wire
fence. The individual adipocytes have a
large central storage area where fats and
oils are stored
Location: Subcutaneous layer of skin; fatty
capsule of kidney, yellow bone marrow;
around the heart
Function: Energy storage, insulation,
protection
13
Photomicrograph of Adipose
Connective Tissue
Dense Fibrous Connective Tissue
(Regular)
• Contains numerous collagen fibers
oriented in the same direction. This
produces great strength in the direction
that the fibers run
Description: Many collagen fibers running in
the same direction. Appears to be “wavy”
Location: Tendons and ligaments
Function: Attaches muscles to bone
(tendons), and bone to bone (ligaments)
Further notes on Dense Connective
Tissue (Regular)
• Is less flexible than Areolar Connective
Tissue but is more resistant to stress. The
collagen fibers are densely packed and
run in on direction.
• There is great strength in the direction of
the fibers, but relatively weak in a direction
at right angles to the direction of the fibers.
• The wavy configuration allows some
stretching.
14
Photomicrograph of Dense Regular
Connective Tissue (Regular)
Hyaline Cartilage Connective
Tissue
• Has a matrix firm enough to bear great
pressure without permanent distortion
Description: Chondrocytes (cartilage cells)
Located in spaces called lacuna, surrounded
by a bluish matrix with collagen fibers
Location: Ends of long bones, between ribs
and sternum, tracheal rings, larynx
Function: Reduces fiction in joints, support
with flexibility
Photomicrograph of Hyaline
Cartilage Connective Tissue
15
Osseous Connective Tissue
(Bone)
• Bone tissue has a hard matrix containing
ions such as calcium and phosphorus
• The matrix is laid around a dense network
of collagen fibers in a layer called lamella
• Canals called Haversian are filled with
nerves, arteries, veins, and lymphatics
Osseous Connective Tissue
(Continued)
Description: A network of Haversian
systems (osteons)
Location: Make up the bones of the body
Function: Protection, support, mineral and
storage. Together with skeletal muscle is
responsible for movement
Photomicrograph of Bone
16
Muscle Tissue
•
Muscle tissue is composed of fibers that
function to contract and shorten the
muscle for contraction
• There are three type of muscle based on
location, structure and function
(1) Skeletal muscle tissue
(2) Cardiac muscle tissue
(3) Smooth muscle tissue
Skeletal Muscle
• So-called because it attaches to bones
and moves bones. Also called voluntary
or striated muscle
• Description: Long striated fibers with the
nuclei located at the edge of the fibers
• Location: Attached to bones by tendons
• Function: Moves bone, posture, heat
production
Photomicrograph of Skeletal
Muscle Tissue
17
Smooth Muscle Tissue
• Composed of elongated cells that are not
striated
Description: Long tapered fibers with a
centrally located nucleus
Location: The walls of hollow organs (such
as the stomach and urinary bladder)
Function: Movement of substance inside the
hollow organ
Photomicrograph of Smooth
Muscle Tissue
Cardiac Muscle Tissue
Description: Branched striated fibers with a
centrally located nucleus
Location: Wall of the heart
Function: Pumps blood to all parts of the
body
18
Photomicrograph of Cardiac
Muscle Tissue
Nervous Tissue
Description: Large cell bodies with obvious
processes extending from them. Many
small nuclei of neuroglia cells
Location: Nervous system
Function: Conducts nerve impulses (Action
potentials)
19