Essentials of Human Anatomy 2

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Transcript Essentials of Human Anatomy 2

Essentials of Human Anatomy
Body Tissues
Dr Fadel Naim
Ass. Prof. Faculty of Medicine
Tissue Level of Organization
• Group of similar cells
– common embryonic origin
– common function
• Histology
– study of tissues
4 Basic Tissues (1)
1. Epithelial Tissue
– covers surfaces because cells are in contact
– lines hollow organs, cavities and ducts
– forms glands when cells sink under the surface
2. Connective Tissue
– supports and binds structures together
– stores energy as fat
– provides immunity to disease
4 Basic Tissues (2)
3. Muscle Tissue
– cells shorten in length producing movement
4. Nerve Tissue
– cells that conduct electrical signals
– detects changes inside and outside the body
– responds with nerve impulses
• Removal of living tissue for microscopic
• Useful for diagnosis, especially cancer
• Tissue preserved, sectioned and stained
before microscopic viewing
• A biopsy is performed after appropriate staging
• Alternatives include
– fine needle aspiration (FNA)
• A simple procedure that can be done using local anesthesia.
• Most helpful in diagnosing soft tissue tumors and bony tumors with
homogenous cell types
• Obtains the least amount of material.
– core needle biopsy
• May be aided by ultrasonography, fluoroscopy, computed
tomography (CT), and magnetic resonance imaging (MRI).
• The surgeon obtains a core of tissue that measures 10 mm by 2 mm.
– open biopsy or incisional biopsy
• A surgical procedure that provides the largest amount and the best
sampling of tissue for pathologic identification.
Epithelial Tissue
• Functions
– Protection
– Sensory functions
– Secretion
– Absorption
– Excretion
Slide 8
General characteristics • cover organs and the body
• line body cavities
• line hollow organs
• have a free ( apical ) surface
• have a basement membrane
• avascular
• cells readily divide
• cells tightly packed
• cells often have desmosomes
• classified according to cell shape and number of cell layers
Types of Epithelium
• Covering and lining epithelium
– epidermis of skin
– lining of blood vessels and ducts
– lining respiratory, reproductive, urinary & GI
• Glandular epithelium
– secreting portion of glands
– thyroid, adrenal, and sweat glands
Cell Shapes
1. Squamous
2. Cuboidal
3. Collumnar
1. Simple
2. Stratified
3. Pseudostratified
Simple Epithelial Tissues
Simple squamous
Simple cuboidal
Simple columnar
Pseudostratified columnar
Epithelial Tissues
Simple squamous –
• single layer of flat cells
• substances pass easily through
• line air sacs
• line blood vessels
• line lymphatic vessels
Simple Squamous
Epithelial Tissues
Simple cuboidal –
• single layer of cube-shaped
• line kidney tubules
• cover ovaries
• line ducts of some glands
Simple Cuboidal
Epithelial Tissues
Simple columnar –
• single layer of elongated cells
• nuclei usually near the basement
membrane at same level
• sometimes possess cilia
• sometimes possess microvilli
• often have goblet cells
• line uterus, stomach, intestines
Simple Columnar Epithelium
Simple Columnar Epithelium
with cilia
Epithelial Tissues
Pseudostratified columnar –
• single layer of elongated cells
• nuclei at two or more levels
• appear striated
• often have cilia
• often have goblet cells
• line respiratory passageways
Pseudostratified Columnar
Stratified Epithelial Tissues
• Stratified squamous
• Stratified cuboidal
• Stratified columnar
Epithelial Tissues
Stratified squamous –
• many cell layers
• top cells are flat
• can accumulate keratin
• outer layer of skin
• line oral cavity, vagina, and
anal canal
Stratified Squamous Epithelium
Epithelial Tissues
Stratified cuboidal –
• 2-3 layers
• cube-shaped cells
• line ducts of mammary glands,
sweat glands, salivary glands,
and the pancreas
Stratified Cuboidal Epithelium
Epithelial Tissues
Stratified columnar –
• top layer of elongated cells
• cube-shaped cells in deeper
• line part of male urethra and
part of pharynx
Stratified Columnar Epithelium
Epithelial Tissues
Transitional –
• many cell layers
• cube-shaped and elongated
• line urinary bladder,
ureters, and part of urethra
Transitional Epithelium
Glandular Epithelium
Composed of cells that are specialized to produce and secrete
Endocrine Glands
• Lack ducts and secrete their products
directly into the interstitial fluid and
• Hormones act as chemical messengers to
influence cell activities elsewhere in the
Exocrine Glands
– Usually maintain their contact with the
epithelial surface by means of a duct.
– Duct secretes materials onto the surface of
the skin or onto an epithelial surface lining an
internal passageway.
Connective Tissues
General characteristics • most abundant tissue type
• many functions
• bind structures
• provide support and protection
• serve as frameworks
• fill spaces
• store fat
• produce blood cells
• protect against infections
• help repair tissue damage
• have a extra-cellular matrix
• have varying degrees of vascularity
• have cells that usually divide
Extra-Cellular Matrix
• Cells rarely touch due to extracellular
• Matrix(fibers & ground substance secreted
by cells
• Consistency varies from liquid, gel to solid
Connective Tissue
Major Cell Types
• fixed cell
• most common cell
• large, star-shaped
• produce fibers
Mast cells
• fixed cell
• release heparin
• release histamine
• wandering cell
• phagocytic
• important in injury
or infection
Connective Tissue Fibers
Collagenous fibers
• thick
• composed of collagen
• great tensile strength
• abundant in dense CT
• hold structures together
• tendons, ligaments
Reticular fibers
• very thin collagenous fibers
• highly branched
• form supportive networks
Elastic fibers
• bundles of
microfibrils embedded
in elastin
• fibers branch
• elastic
• vocal cords, air
Connective Tissues
Connective tissue proper
• loose connective tissue
• adipose tissue
• reticular connective tissue
• dense connective tissue
• elastic connective tissue
Specialized connective tissue
• cartilage
• bone
• blood
Connective Tissues
Loose connective tissue
• mainly fibroblasts
• fluid to gel-like matrix
• collagenous fibers
• elastic fibers
• bind skin to structures
• beneath most epithelia
• blood vessels nourish
nearby epithelial cells
• between muscles
Adipose tissue
• adipocytes
• cushions
• insulates
• store fats
• beneath skin
• behind eyeballs
• around kidneys and heart
Connective Tissues
Reticular connective tissue
• composed of reticular fibers
• supports internal organ
• walls of liver, spleen,
lymphatic organs
Dense connective tissue
• packed collagenous fibers
• elastic fibers
• few fibroblasts
• bind body parts together
• tendons, ligaments, dermis
• poor blood supply
Connective Tissues
Elastic connective tissue
• abundant in elastic fibers
• some collagenous fibers
• fibroblasts
• attachments between bones
• walls of large arteries, airways, heart
Bone (Osseous Tissue)
• solid matrix
• supports
• protects
• forms blood cells
• attachment for muscles
• skeleton
• osteocytes in lacunae
Cartilage Connective Tissue
– Weaker than bone
– More flexible than bone
• Cells in an abundant matrix.
• Cell Types
– Chondroblasts
– Chondrocytes in lacunae
• Avascular
3 Major Functions of Cartilage
• Supporting soft tissues.
• Providing a gliding surface at articulations
• Providing a model for the formation of
most of the bones in the body.
Types of Cartilage
• Three types of cartilage:
– Hyaline cartilage
Most abundant kind
Has a perichondrium (membrane)
Associated with synovial joints
Most bones first modeled in hyaline cartilage
– Fibrocartilage
• Has collagen fibers
• Intervertebral discs, pubic symphysis
– Elastic cartilage
• Has elastic fibers
• Ear, respiratory tubing
Types of Epithelial
• line body cavities
that do not open to
the outside
• reduce friction
• inner lining of
thorax and abdomen
• cover organs of
thorax and abdomen
• secrete serous fluid
• line tubes and organs
that open to outside world
• lining of mouth, nose,
throat, etc.
• secrete mucus
•covers body
• skin
• composed entirely of
connective tissue
• lines joints
Muscle Tissues
Skeletal muscle
General characteristics
• muscle cells called
muscle fibers
• contractile
• three types
• skeletal
• smooth
• cardiac
• attached to bones
• striated
• voluntary
Smooth muscle
• walls of organs
• skin
• walls of blood vessels
• involuntary
• not striated
Cardiac muscle
• heart wall
• involuntary
• striated
• intercalated discs
Muscle Tissues
Skeletal Muscle
Smooth Muscle
Cardiac Muscle
Nervous Tissue
• Sometimes termed neural tissue.
• Found in brain, spinal cord, and peripheral
• Consists of neurons, or nerve cells, and
glial cells that support, protect, and
provide a framework for neurons.
• Detect stimuli, process information quickly, and
rapidly transmit electrical impulses from one
region of the body to another.
• Prominent cell body functions in control;
information processing, storage, and retrieval;
internal communication.
• Processes extend from the nerve cell
– Dendrite
– Axon
Wound Healing: Mechanisms
• Contraction - amputation
• Epithelialization - ulcer
• Connective tissue deposition laceration
Tissue Repair: Restoring
• Worn-out, damaged tissue must be replaced
• Fibrosis = replacement with stromal connective
tissue cells (scar formation)
• Regeneration = replacement with original cell
types (parenchymal cells)
– some cell types can divide (liver & endothelium)
– some tissues contain stem cells that can divide
• bone marrow, epithelium of gut & skin
– some cell types can not divide & are not replaced
• muscle and nervous tissue