Tissues
Definitions
• Tissues are groups of cells that have the
same structure and functions.
• The study of tissues is called HISTOLOGY
– Histos: tissue; ology: field of study
Classification of tissues
•
Epithelial
–
Simple (one layer)
•
•
•
Squamous
Cuboidal
Cilindrical
–
–
•
–
With microvilli or “brush border”.
Cilia
Pseudostratified
Stratified (several layers)
•
•
•
•
Squamous
Cuboidal
Cilindrical
Transition
Classification of Tissues
• Connective
– Proper
• Mesenchyme
• Loose connective
– Areolar
– Reticular
– Adipose
• Dense connective tissue
– Dense regular
– Dense irregular
– Cartilage
• Hyaline
• Elastic
• Fibrocartilage
– Oseous
– Blood
Classification of Tissues
• Muscular
– Skeletal muscle
– Cardiac muscle
– Smooth muscle
• Nervous tissue
Epithelial tissue
• Characteristics
– Polarity: posses apical surface and basal surface.
– Cellularity and special contacts (tight junctions).
– Supported by connective tissue through basement
membrane (basal lamina + reticular lamina).
– Avascular: no blood vessels.
– Regenerative: cells regenerate.
• Function: lining of surfaces (interior or exterior
to the body)
Figure 3.5
Simple Epithelium
•
Simple Squamous epithelium:
– Description: “scale like” flat cells.
– Function: Allows passage of substances
through filtration and diffusion.
– Located in endothelium (lining of blood
vessels), kidney glomeruli, air sacs in the
lung (alveoli).
Simple squamous
Figure 4.1
Figure 4.2
Simple Epithelium
• Simple cuboidal epithelium
– Description: cells are of cubic form.
– Function: secretion and absortion.
– Located in kidney tubules, ovary surface
Figure 4.3
Simple Epithelium
•
Simple Columnar (cilindrical) epithelium
–
–
–
Description: tall cells with round or oval nucleus.
Function: Absorption that can be increase by
cytoplasmatic projections of microvilli, secretion of
mucus. If ciliated, it propels mucus by ciliary action.
Located in digestive track, small intestine, uterus,
lower respiratory system (bronchioles).
Figure 4.4
Figure 4.5
Simple Epithelium
•
Pseudostratified columnar:
– Description: single layer of cells, with
apparent different heghts due to the position
of the nucleus.
– Function: secretion and propulsion of
mucus.
– Located in the trachea.
Figure 4.6
Simple Epithelium
• Pseudostratified columnar
– Description: appears to be stratified
squamous and cylindrical.
– Function: allows stretching and containing
urine (avoiding leakage into adjacent tissues).
– Found in the bladder.
Stratified Epithelium
• Stratified Squamous epithelium
– Description: multilayer squamous cells.
– Function: protection of underlying tissues.
– Location: Non keratinized (thin skin) are found
in the esphagous, mouth,vagina. Keratinized
(thick skin): palm and feet.
Figure 4.7
Stratified Epithelium
• Stratified Cuboidal epithelium
– Description:bilayer of cuboidal cells.
– Function: secretion.
– Found in the ducts of glands such as
mammary, sweat and salivary.
Figure 4.8
Stratified Epithelium
• Stratified Columnar epithelium
– Description: Several layers of cylindrical cells.
– Function: secretion.
– Found in the male urethra.
Figure 4.9
Stratified Epithelium
• Transitional epithelium
– Description: Resembles both stratified
sqamous and stratified cuboidal epithelium;
basal scells are cuboidal or cylindrical;
surface cells are domed or squamous.
– Function: Allows distension and stretching.
– Found in the lining of the urethers, bladder
and par of the urethra.
Figure 4.10
Connective Tissue Proper
• Areolar loose connective tissue
– Description: loose collagen reticular and
elastic fibers, prescence of fibroblasts,
macrophages, mast cells.
– Function: wraps provide nutrients and
cushions organs.
– Found under epithelia, surrounds capillaries
and packages organs, .
Connective Tissue
• Function: Support/connect tissues.
• Description:
– Cells:
•
•
•
•
Fibroblast: most common.
Chondrocytes, ostoecytes: secrete respective extracellular matrix.
Myofibroblasts
Adipocytes
– Fibres
• Collagen
• Estastin
• Reticulin
– Ground substance: amorphous transparent material.
• Glucosaminoclycans (GAGs): Hyaluronic acid
• Glycoproteins: fribrillin, fibronectin, integrin.
Figure 4.11
Connective Tissue Proper
• Reticular loose connective tissue
– Description: predominant reticular fibers in a
network.
– Function: Provides structure to lymph organs.
– Located: Found in lymph organs (thymus,
lymph nodes).
Figure 4.13
Connective Tissue Proper
• Regular Dense connective tissue
– Parallel arranged collagen fibers with
fibroblasts.
– Function: Attaches muscles to bones or bones
to bones. Posses great tensile strength in one
direction.
– Forms tendons, ligaments, aponeurosis.
Figure 4.15
Connective Tissue Proper
• Irregular Dense connective tissue
– Description: Irregular arranged fibers with
fibroblasts. Forms the articulation capsules of
organs and joints.
– Function: Posses great tensile strength in
several directions.
– Location: reticular layer of the dermis, fibrous
capsues of organs and joints.
Figure 4.14
Connective Tissue Proper
• Elastic Connective tissue
– Description: Irregular arranged elastic fibers
with fibroblasts. Makes the tunica media in
blood vessels.
– Function: Provides elasticity to the blood
vessels.
– Location: Tunica media of arteries and veins.
Figure 4.16
Connective Tissue Proper
• Adipose loose connective tissue
– Description: adipocytes embeded in scarce
areolar tissue.
– Function: Energetic reserve, cushioning,
thermal insulation.
– Location: Hypodermis, kidneys, abdomen,
breasts.
Figure 4.12
Cartilage
• Hyaline Cartilage:
– Description: firm amorphous matrix
synthesized by chondroblasts. Mature matrix
holds chondrocytes in lacunae.
– Function: Allows resilience, flexibility and
compressibility to forces.
– Located: embryonic skeleton, joints, nose,
trachea, ribs.
Figure 4.17
Cartilage
• Elastic cartilage:
– Description: similar to hyaline, but a grater
ratio of elastic fibers.
– Function: maintain structure while possesing
great flexibility.
– Location: outer ear, epiglotis.
Figure 4.18
Cartilage
• Fibrocartilage:
– Description:similar to hyaline but a greater
ratio of collagen fibers.
– Function: posses high tensile strength but
maintaining compressibility.
– Located: intervertebral discs, knee joint, pubic
symphisis.
Figure 4.19
Bone
• Compact bone
– Description: Hard, calcified matrix.
Impereameable. Vascularized. Osteocytes in
lacunae.
– Function: hematopoiesis (reb blood cell
formation), storage of calcium and minerals.
Composes the skeleton.
– Location: bones
Figure 4.20
Figure 4.21
Blood
• Description: red, white cells and fibrous
proteins (firbinogen) in a fluid matrix
(plasma)
• Function: transport of nutrients, wates,
gases throughout the body.
• Located: within blood vessels.
Figure 4.22
Muscle
• Skeletal muscle
– Description: long, cylindrical, multinucleated,
and striated.
– Function: Voluntary movement; locomotion.
– Located: skeleton
Figure 4.28
Figure 4.30
Muscle
• Cardiac Muscle
– Description: branched, striated, uninucleated
cells, connected by cell juntions (intercalated
discs)
– Function: propulsion of blood from the heart.
– Location: heart.
Figure 4.31
Muscle
• Smooth muscle
– Description: spindle shaped, uninucleated, no
striations.
– Function: creates peristaltic movement in
digestive system and involuntary contraction
of arrestor pili.
– Lacted: hollow organs, dermis
Figure 4.32
Nervous tissue
• Description: Composed mainly by neurons
and support cells (glial cells).
• Function: transmit electrochemical signals
to sense and control the body.
• Location. Brain, spinal cord, nerves.
Figure 4.33
Figure 4.35
Figure 4.37
Figure 4.38
• Note: to extra practice, you find an atlas in
the lab book as well as a tutorial in the
PhysioEx CD.