Introduction to Anatomy Connective, Epithelial and Supportive Tissue

8/12/2019 Introduction to Anatomy Connective, Epithelial and Supportive Tissue

1/116


2/116

Anatomical positionsobject stands erect (upright positions)

facing the observer

arms placed at the sides

palms of the hands turned forward


3/116


4/116

Planes and sectionsmidsagittal plane is a vertical plane that divides the body or

an organ into equal left and right side

parasagittal plane is vertical plane parallel to sagittal and itdivides the body or an organ into unequal left and right side

frontal plane divides the body or organ into anterior (front)and posterior (back) parts

transverse (cross-sectional) plane divides the body or organinto superior (top) and inferior (bottom) parts


5/116


6/116

Directional terms

superior (cephalic, cranial):toward the head or the upper part of the structure (theheart is superior to the liver)

inferior (caudal):away from head or toward the lower part of thestructure (the stomach is inferior to the lungs)


7/116


8/116

Directional terms

anterior (ventral):at the front of the body (sternum is anterior to the heart)

posterior (dorsal):at the back of the body (the esophagus is posterior to

trachea)


9/116

Directional terms

medial:nearer or at the midline of the body

lateral:farther from midline


10/116


11/116

Directional terms

proximal:nearer to the attachment of extremity to the trunk

distal:farther to the attachment of extremity to the trunk


12/116


13/116

Directional terms

parietal:pertaining to or forming outer wall of body cavity

visceral:pertaining to the covering of an organ within the body

cavity


14/116

Levels of structural organization of human body

atoms, molecules cells tissues

organs systems

organism


15/116

Types of tissues

epithelial tissue covers body surface, lines organs,body cavities, and ducts, and forms glands

connective tissue protects and support body and

its organs, binds organs together, stores energy andprovides immunology muscle tissue movement and regeneration of force nervous tissue initiates and transmittes nerve

impulses, coordinates whole organism


16/116

EPITHELIAL TISSUE

epithelial tissue is consisting of one or more layers ofcells that form continuous sheets with minimal

extracellular matrix

covers body surface, lines organs, body cavities, andducts, and forms glands


17/116

General features of epithelia

epithelial cells have apical surface (free) exposed to a body

cavity

basal surface is attached to basal membrane

epithelial cells are attached to each other by various cell junctions

epithelia are avascular (diffusion via basal membrane)

epithelia have a nerve supply


18/116


19/116

Main functions of epithelia

protection (vessel, esophagus)

filtration (regulatory barrier)

secretion (thyroid gland)

digestion (pancreas)

absorption (small intestine)

sensory reception


20/116

Basal (basement) membrane

thin extracellular layer formed by two layers, basallamina and reticular lamina

basal lamina is consist of proteins, glycoproteins e.g.collagen IV , laminin

structural support for epithelial cells

main regulatory barrier between epithelium andsurrounding tissue


21/116

Membrane specializations of epithelia:

intercellular junctions tight junctions

seal the intercellular spaces

protection against penetration fromluminal contents (bloodbrain barrier, testicular barrier)

located beneath the apical surface of cells

adhering junctions (zonula adherens, desmosomes, hemidesmosomes)

bind epithelial cells ( not so tight ), anchor epithelium to the cytoskeleton

located beneath tight junctions


22/116

Membrane specializations of epithelia:

intercellular junctions

gap junctions (communicating junctions)

form hexamers with hydrophilic pore

participate in passage of small molecules between cells


23/116


24/116

Luminal surfaces Cilia

long motile structureseasily visible by light microscopee.g. columnar pseudostratified epithelium in trachea

Microvilli short often extremely numerous projections of plasma membrane

visible only in electron microscopelocated in simple columnar epithelium in small intestine

Stereocilia extremely long microvilli

visible in the light microscope not motile located in reproductive tract in epididymis


25/116

Classification of epithelia

number of cell layers simple epithelia

stratified epithelia

shape of epithelial cells (shape of nucleus) squamous

cuboidal

columnar

presence of surface specializations cilia

microvili

stereocilia


26/116

Simple squamous epithelium

composed of flattened irregularly shaped cells forming acontinuous surface which may be referred to as

pavemented epithelium

Function participate in passive and active transport of either fluids orgases

Located in either blood and lymphatic vessels ( endothelium ), lining the cavities (pleural, pericardial)


27/116


28/116

Simple squamous epithelium (endothelium)


29/116

Simple squamous epithelium (endothelium)

nuclei of endothelial cells


30/116

Simple cuboidal epithelium

intermediate form between squamous and columnarepithelium

nucleus is located in the center of the cell

Function : covering , secretion

lining small ducts in pancreas , lining follicles in thyroid

gland , etc.


31/116


32/116

Simple cuboidal epithelium (thyroid gland)


33/116

Simple columnar epithelium

cells are taller , nuclei are elongated and located towardbasement membrane

Function : protective , secretion , absorption

Located in stomach , small intestine


34/116


35/116

Simple columnar epithelium (small intestine)


36/116

Pseudostratified columnar epithelium

cells are in one layer (all cells rest on basement membrane),different heights of cell and thus positions of nuclei creatingillusion of stratification

Function : protection , secretion ,

Located in respiratory system with cilia (trachea, bronchus) etc. or reproductive

system (epididymis)


37/116

Mi i ti


38/116

Microscopic preparationPseudostratified columnar epithelium (trachea)

cilia

Basalmembrane


39/116

Transitional epithelium

special form of stratified epithelium , columnar or cuboidal

cells near the basement membrane, large surface cells often with two nuclei

Function protection against mechanical stretch and toxic wastes in urinary

tract

Location urinary tract (urinary bladder)


40/116

Transitional epithelium

Microscopic preparation


41/116

Microscopic preparation Transitional epithelium (urinary bladder)

Microscopic preparation


42/116

Microscopic preparation Transitional epithelium (urinary bladder)


43/116

Stratified squamous epithelium

consist of variable number of cells layers , columnar orcuboidal cells near the basement membrane ( basal layers )and flattened cells in surface regions

Function : mechanical protection , preserve leakage of water from tissue ( dehydration )

Location :

stratified squamous epithelium in digestive system (liningoral cavity, esophagus)stratified squamous epithelium with keratin

(accumulation of keratin in cells during maturation) constituteepithelial surface of skin


44/116


45/116

Stratified squamous epithelium (esophagus)


46/116

Stratified squamous epithelium with keratin (skin)


47/116

Glandular epithelium

consist of specialized type of epithelial cells that are

capable to form secretions

exocrine glands:

secrete proteins (pancreas), lipids (sebaceous gland), carbohydrates (salivary gland), wax, either directly or via ducts onto free tissuesurface

endocrine glands :secrete hormones (chemical messengers) directly into extracellular

fluid and than into the systemic circulation

ductless glands

f


48/116

Morphology of glands

simple glands: single unbranched duct

compound glands: branched duct system

tubular glands: tubular secretory portions

acinar glands: acinar secretory portions


49/116

E i l d


50/116

Exocrine glands

Merocrine secretion (eccrine):

secretory product is formed and then discharge by exocytosis (generally proteins)

no changes in cell shape

most common form of secretion in exocrine glands

Location: salivary gland, pancreas

M i ti ( )


51/116

Merocrine secretion (pancreas)

E i gl d


52/116

Exocrine glands

apocrine secretion:

secretory product is accumulated at apical (free) surface of cells

enlargement of the cells

pinch off the portion of cell discharge of secretory product(generally lipids) in the vesicle diminishing of the cells

myoepithelial cells participate on discharging of secretory product

Location: sweat glands, mammary glands

Apocrine secretion (sweat gland)


53/116

Apocrine secretion (sweat gland)

Myoepithelial cells

Exocrine glands


54/116

Exocrine glands

Holocrine secretion:

involves discharge of whole secretory cells with subsequentdisintegration of the cell to release the secretory product

location: sebaceous gland

Holocrine secretion (sebaceous gland)


55/116




56/116




57/116




58/116


Endocrine glands


59/116

Endocrine glands

secrete hormones (chemical messengers) directly into

extracellular fluid and than into the systemic circulation no ducts

Endocrine gland (Langerhans islet in pancreas)


60/116

Endocrine gland (Langerhans islet in pancreas)


61/116


62/116

CONNECTIVE (SUPPORTING) AND MUSCLE TISSUE

Main characteristics of the connective tissue


63/116

Composed of cells and extracellular matrix (ground substance and fibers)

Provides structural and metabolic support for other tissues and organs

Strenghten other body tissues

Protects and insulate body organs

Participate in the immunity reactions in human body

Highly vascular and nervous tissue

the exchange of metabolities,

nutrients and waste between the tissues and the circulatory system

C ti ti ll


64/116

Connective tissue cellsFibroblasts ( osteoblasts, chondroblasts, odontoblasts )

Large, flat, spindle-shaped cells

They secrete connective fibers and ground substance

Fibroblasts participate in the wound healing (the retraction of

damaged tissue)Macrophages

Derived from the monocytesParticipate on phagocytosis and thus provide vital defense for

the body ( immunity )

Connective tissue cells


65/116

Mast cells

Abundant alongside blood vessels

Produce histamine and other chemicals that participate on the inflammatory

reactions (dilatation of blood vessels, increasing of permeability of vessels)Produce heparin anticoagulant activity

Adipocytes (fat cells)

Form the adipose tissue

Responsible for the storage and metabolism of fat (energy)

Good insulator prevent against the heat loss

Important for prductions of cytokines and inflammation

Connective tissue matrix fibers


66/116

Connective tissue matrix - fibers

Collagen

Main fibre and the most abundant in the humanbody

Collagen is polymerized from the tropocollagen and

forms collagen bundles

Participate on the tensile strength of tissues

Atherosclerotic lesion collagen


67/116

g

Connective tissue matrix fibers


68/116


Elastin

Structural protein that forms fibres and sheets

Abundant in the skin , lungs, and blood vessels

Provides elastic properties of the tissues ( stretch xretract )

Atherosclerotic aorta elastin


69/116



70/116

Reticular fibres

Form lattice or reticulum

They are common in the lymphatic glands,

hematopoietic organs and form meshlike center

called the stroma

Kidney reticular fibres


71/116

Connective tissue matrix ground


72/116

substance

Amorphous (no shape) transparent material formedpredominantly by polysaccharides (glycosaminglycans,proteoglycans)

These polysaccharides molecules form flexible gel through which metabolites may diffuse

Classification of connective tissue


73/116


Loose connective tissue

characterized by the small amount of fibers, the maincomponents are cells and ground substance Packing and binding tissue that surrounds muscles ,nerves and vessels

Areolar connective tissue Strengthen epithelial tissueSurrounds vessels and muscles (fascia)Form subcutaneous layer (attach the skin to surrounding tissue)



74/116

Loose connective tissue

Adipose tissue Responsible for the storage and metabolism of fat (energy)Good insulator prevent against the heat loss

It is present wherever areolar tissue is presented White adipose tissue comprises up to 20-25% of total body weight in adults

Brown adipose tissue is found in newborn mammals andhibernating animals

where is important in the temperature regulationprotect against obesity (burning off excess of energy)



75/116

Loose connective tissue Reticular connective tissue

It forms the fibre skeleton (network) of haemapoieticorgans (bone marrow, liver, spleen, lymphatic glands)



76/116

Dense connective tissue is formed predominantly by numerous and thick fibres with afew cells

Dense regular or irregular connective tissue (accordingto the orientation of collagen bundles)

Provides great strength of the tissues e.g. tendon (ligament) which bind muscles to bonesLocated in the skin, GI tract

Elastic connective tissue Provides elastic (stretch and retract) properties of tissue e.g.aorta , portions of the larynx , epiglotis ..

Hyaline cartilage (gristle)


77/116

y g (g )

Most abundant cartilage in the human body, e.g. trachea(tracheal rings)

Participate in the forming of the embryonal skeleton

Amorphous glass-like ground substance that overlappingcollagen bundles (thus not visible)

Small aggregations of chondrocytes embedded in thelacunae

Hyaline cartilage (gristle)


78/116

y g (g )

Hyaline cartilage -trachea


79/116

perichondrium

Hyaline cartilage -trachea


80/116

chondrocytes

perichondrium

Elastic cartilage


81/116

Occurs in the external ear and epiglottis

The presence of the visible numerous and branching elastic fibres rounded the chondrocytes


82/116

Fibrocartilage


83/116

Intermediate between dense connective (fibrous)tissue and cartilage

Occurs in intervertebral disc

The bone tissue


84/116

The bone is composed of the cells and extracellular matrix

(predominantly collagen) called osteoid, which becomes

mineralized by the depositions of calcium

hydroxyapatite rigidity and strength

Bone tissue functions


85/116

The support and the protection of soft tissues and

organs (brain)

Participate on the movement

Bone marrow the hematopoiesis

The source and the storage of calcium and phosphor

The cells of bone


86/116

Osteoblasts synthesize osteoid and participate in the mineralization They line osteoid

Osteocytes derived from the osteoblastsEntrapped inside the osteoid participate on the nutrition

Osteoclasts Capable of phagocytosis, cells that participate in the eroding of thebone and thus together with osteoblasts necessary for the constantturnover and remodeling of the bone and the formation of medullary cavity during ossification

The structure of the bone


87/116

Diaphysis the main portion of the bone Epiphysis the ends of the bone

Periosteum

surface fibrous membrane that covers the bonecomposed of two layers that contains fibres (Sharpeysfibers)

contains blood vessels and nerves that penetrate throughthe Volkmanns canal into the bone tissue ( nutrition )

Bone tissue

Structure of bone


88/116

Endosteum Inner fibrous layer that is between bone tissue and marrowcavity

Marrow cavity Contains bone marrow

Red bone marrow Occurs in the whole bone (epiphysis, diaphysis) in prenatal

period - hematopoiesis Occurs only in the epiphysis in adults

Yellow bone marrow Occurs in diaphysis in adults Hematopoietic tissue is replaced by fat tissue


89/116


90/116

1. Endosteum


91/116

2. Periosteum

3. Vessel in Haversian canalcoming from periostthrough the Volkmannscanal

4. Sharpeys fibers

5. Vessel from periosteum

Spongy (cancellous) bone


92/116

Occurs in the epiphysis and in the inner portion ofthe bone

Irregular arrangement of lamellae forms thin

plates called trabeculae

Does not contain true osteons like in

Compact (dense) bone

O i di h i d i th t ti f th b


93/116

Occurs in diaphysis and in the outer portion of the bone

Typical structure Haversian system (osteon)

Composed of the Haversian canal located in the center (vessels andnerves inside)

Concentric, hard, calcified lamellae surrounding the canal

Osteocytes located in small spaces between lamellae called lacunae

(lacuna=little lake)

Radiating in all directions from the lacunae the elongation of osteocytes

in the canals (called canaliculi - nutrition, metabolites, waste)

Interstitial lamellae - areas between osteons


94/116

Microscopic preparation Bone


95/116

Haversian system

Haversian canal

Concentric lamellae

Osteocytes in lacunae



96/116



97/116

osteocyte

Osteocytesprocesses

Ossification Bone formation

Th i i h f i f b d i


98/116

The process comprising the formation of bone e.g. duringembryonal period, during reparation of bone in adults.

Intramembranous ossification Formation of bone on or in fibrous connective tissue

Typical for some skull bones

The principle:

Osteoblast secrete organic matrix

the calcification

theformation of trabeculea the formation of periosteum spongy bone

Endochondral ossificationFormation of the bone directly from the hyaline cartilage

Typical for some long bones

The principle:


99/116

The principle: Hyaline cartilage is replaced by the bone tissue

Formation of the periosteal bone collar ( calcification of periosteum )

formation of the primary ossification center longitudinal ossification(delivery of nutritions, precursors of osteoblasts into cartilage through the

vessel)

Hypertrophy of chondrocytes calcification of cartilage matrix + break

down of chondrocytes the formation of spongy bone by osteoblasts

calcification of spongy bone ossification center enlarges toward the ends

of the bone osteoclasts break down newly formed spongy bone

formation of marrow cavity

Secondary ossification center ossification in radial directions


100/116

Muscle tissue

1) Sk l t l l ti


101/116

1) Skeletal muscle tissue Attached primarily to the bones and responsible for

the movement

Also called striated because of alternating dark andlight band (striations)

Voluntary muscle tissue because it is controlled byyour own consciousness

Skeletal muscle composition characterization

Basic unit muscle fibers (composed of myofibrils thatt i t til fil t ti d i )


102/116

Basic unit muscle fibers (composed of myofibrils thatcontains contractile myofilaments actin and myosin ) aregrouped together into the fascicles with delicate supporting

tissue called endomysium that occupying spaces betweenindividual muscle fibers

Each fascicle (bundle) is surrounded by loose connectivetissue called perimysium

Each muscle is composed by many fascicules (bundles) that are surrounded by dense collagenous sheath calledepimysium


103/116


104/116


105/116

Microscopic preparation skeletal muscle


106/116

Skeletal muscle fibers with numerous nuclei located atthe periphery Cross-striation of the fibers (alternating of light anddark bands)



107/116



108/116

Smooth muscleSpecialized for the long term contractions


109/116

Contraction and relaxation is independent on theconsciousness

Contraction and relaxation is often rhythmic of wave-like fashion (distal movement of the food in the intestine)

Smooth muscles are under the control of autonomicnervous system

Structure of smooth muscles differs from an organ to organaccording to the functional requirements.


110/116

Microscopic preparation smooth muscle


111/116

Smooth muscle cell

Cardiac muscle

Many structural similarities between skeletal and smoothmuscles


112/116

muscles

Presence of the striation similar to the skeletal muscles

Under control of autonomic nervous system (similar to

the smooth muscle) thus, cannot be controlled voluntarily

Cardiac muscle cells has shape like letter Y

One or two nuclei are located centrally

The presence of intercalated disks that occurs betweentwo adjacent cells and participate on rapid spread of

contractile stimuli


113/116

Microscopic preparation cardiac muscle

d l ll h h l k l


114/116

Cardiac muscle cells has shape like letter Y Centrally located nucleus or nuclei

The presence of intercalated disks



115/116

Intercalated disc



116/116

Cigar-like nucleus of cardiomyocyte

Documents

Introduction to Anatomy Connective, Epithelial and Supportive Tissue