•
Basic science
•
Studies and describes the structure of the body at the light microscopic level
•
Aim of course
•
Present histology in relation to the principles of :
Physiology Biochemistry Molecular biology
Histological structure of human organism : Cells, Intercellular Liquids, Intercellular Substances : Ground
Substances and Fibers
Tissues : Concept and Classification
Epithelium
Connective tissue
Muscle tissue Nervous tissue
Epithelial Tissue
Cover ( exterior of the body )
Line ( of body cavities, tubes, or ducts )
Major functions : Selective diffusion,
absorption,
Secretion,
Physical protection
Cell junctions , basement membrane
Epithelial cells are closely bound to one another
Provide physical strength & mediate exchange of information and metabolites.
Basement membrane
separate epithelia from underlying supporting tissues and are never penetrated by blood vessels
Simple squamous epithelia : Flattened simple epithelia
•
Selective diffusion, absorption or secretion.
•
alveoli ,
•
blood vessels ( endothelium ),
•
body cavities ( mesothelium ),
Simple cuboidal epithelia
•
Secretory , excretory or absorptive functions
•
Ducts of the kidney ,
•
Salivary glands and pancreas
Simple columnar epithelia
•
highly absorptive surfaces ( small intestine )
•
highly secretory surfaces ( stomach )
•
Microvilli ( striated or brush border ) – small intestine ( absorptive function )
•
Cilia ( ciliated ) – female reproductive tract ( secretory function )
•
pseudostratified columnar ciliated epithelium
Cilia never present on stratified epithelia
Respiratory system ( mucociliary escalator )
Stratified epithelia
•
consisting of two or more layers of cells
•
protective function
•
degree and nature of the stratification are related to the kinds of physical stresses
•
classification is based on the shape and structure of the surface cells
•
Stratified squamous epithelium
•
Stratified squamous keratinising epithelium
•
Stratified cuboidal epithelium
•
Transitional epithelium
Stratified squamous epithelium
•
consists of a variable number of cells layers :
•
cuboidal basal layer
•
flattened surface layer
is well adapted to withstand abrasion , and is poorly adapted to withstand desiccation lines :
•
oral cavity , pharynx , esophagus , anal canal , uterine , cervix and vagina
Stratified squamous keratinising epithelium
•
specialized form of stratified squamous epithelium ( epithelial surface of the skin ) epidermis
•
is adapted to withstand the constant abrasion , and desiccation
•
accumulate cross-linked cytoskeletal protein keratin K ( keratinisation )
Stratified cuboidal epithelium
•
only two or three layers
•
not involved in significant absorptive or secretory activity but provides a more robust lining than would
be afforded by a simple epithelium
•
lining of the larger secretory ducts of exocrine glands
Transitional epithelium
•
form of stratified epithelium
•
urinary tract in mammals
•
highly specialised : a great degree of stretch and to withstand the toxicity of urine
•
it has some features which are intermediate between stratified cuboidal and stratified squamous
epithelia
•
Membrane specialisation of epithelia
•
Intercellular surfaces
Cell junctions
•
Occluding J.- tight J. - zonula occludens
•
Adehering J. - zonula adherens ,
•
macula adherens - ( desmosomes )
•
Communicating J. gap , nexus J.
Luminal surfaces : Microvilli, Cilia, Stereocilia
Basal surfaces : Basement membrane, hemidesmosomes
•
ZO zonula occludens , ZA zonula adherens , MA macula adherens
•
Macula adherens : strong attachment structure; A. Disc-shaped structure, B. Complex structural
appearance, C. Tonofilaments –
play a role in dissipating physical forces throughout the cell from the attachment site
•
Adhering junctions and communicating junctions are not exclusive to epithelia and are also present in
cardiac and viseral muscle
•
where they appear to serve similar functions
Microvilli
•
short ( 0.5 – 1 µm ) and finger-like projections ,
•
specialised for absorption ,
•
3000 regular microvilli per cell ( highly absorptive sites )
•
striated or brush borders
•
each microvilli contains fine actin filament (F)
Cilia
•
7 to 10 µm in length
•
parallel rows, in the respiratory and female reproductive tracts
•
Up to 300 cilia
•
Each cilium contains :
•
Central core – axoneme ( 20 microtubules )
•
Basal body ( identical to that of a centriole )
Stereocilia
•
Long microvilli
•
are found in small numbers in parts of the male reproductive tract ( epididymis )
•
Do not have the internal structure of cilia
Glandular epithelium , Exocrine glands
•
The morphology of the gland
•
single, unbranched duct
•
secretory portions : tubular or acinar , coiled or branched
•
branched duct system
•
secretory portions have similar morphological forms to
•
those of simple glands
The means of discharge of secretory form the cells
•
Merocrine secretion ( eccrine ) - salivary glands
•
Apocrine secretion - breast , sweat glands
•
Holocrine secretion - sebaceous glands
Endocrine glands
•
ductless
•
secretory products – HORMONES
•
rich network of small blood vessels .
Connective tissue
mesenchyme, mesenchymal cells, mesoderm.
•
Provide a matrix that connects and binds the cells and organs and ultimately support to the body.
•
Medium through which nutrients and metabolic wastes are exchanged between cells and their blood supply.
•
Components of connective tissue:
•
Cells, Fibers, Ground Substance
Cells :
•
fibroblasts,
•
macrophages,
•
mast cells,
•
plasma cells
•
leukocytes.
Fibroblasts
o
Active form
o
Quiescent form
•
Components of matrix
•
Growth factors
 Regeneration
 Myofibroblasts = wound contraction
Macrophages Mononuclear Phagocyte System
o
Monocyte
macrophage
o
Histiocyte
o
Kupffer c., Microglial c., Langerhans c., Osteoclasts
o
Macrophages , Epithelioid c. , Multinuclear giant c.
o
Antigen – presenting cells.
Connective tissue mast cell
•
Mucosal mast cell
o
Specific receptors of IgE
o
Degranulation
o
Histamine,
o
Heparin,
o
Sulfated glycosaminoglycans,
o
Leukotrienes,
o
Slow-Reacting Substances of anaphylaxis.
o
Immediate hypersensitivity reactions
o
Anaphylactic shock
o
allergen
antibodies
plasma cells
•
B lymphocytes
•
Synthesis of antibodies
Fat cells
Leukocytes
•
Diapedesis
•
Inflammation
•
Chemical mediatores
•
Increase of blood flow
•
Vascular permeability
•
Chemotaxis
•
phagocytosis
Classic signs of inflammation = Celsus signs
•
Swelling-edema
•
Redness
•
Heat
•
Pain
•
Disturbed function
Fibers
o
Collagen
o
Reticular fibers
o
Elastic fibers
Collagen synthesis :
( fibro-, chondro-, osteo-, odonto- ) blasts
•
Collagens that form fibrils : I, II, III, XI
•
Fibril-associated collagens : IX, XII, XIV
•
Collagen that form anchoring fibrils : VII
•
Collagens that form networks : IV
•
1000 amino acid
•
3 chains
•
Some molecules tropo
•
Some fine fibrils
fibril
•
Some fibrils
fiber
polypeptide
tropocollagen
fine fibril
I
skin, tendon, bone, dentin
tension
II
cartilage, vitreous body
pressure
III
skin, muscle, blood vessels
structural maintenance
IV
all basement membranes
V
fetal tissues,skin, bone,
participates in type
placenta
I collagen function
support, filtration
reticular
•
Collagen type III
•
Not visible
•
Black – impregnation with silver salts
•
Argyrophilic
•
•
Gr. argyros = silver, philein = love
Periodic acid-Schiff +
•
6 – 12% hexoses ( sugar chains )
Elastic
•
Three types :
•
Oxytalan : Gr oxys = thin, resistant to pulling F.
•
Bundle + glycoproteins =
fibromodulin I & II
fibrillin
•
Elaunin: elastin + microfibrils
•
Elastic : collagen + desmosine, isodesmosine.
•
A: In early stages of formation, developing fibers consist of numerous small glycoprotein microfibrils.
•
B: With further development, amorphous aggregates of elastin are found among the microfibrils.
•
C: The amorphous elastin accumulates, ultimately occupying the center of an elastic fiber delineated by
microfibrils.
•
Ground substance :
•
Glycosaminoglycans, GAGs
•
Proteoglycans,
•
Multiadhesive glycoproteins:
•
Fibronectin
•
Laminin
•
Integrins
•
Huge molecules
•
Hydrophilic
•
Electrostatic ( ionic )
Proteoglycans
•
Fibronectin
•
Laminin
•
Integrins
•
A: Proteoglycans contain a core of protein to which molecules of glycosaminoglycans (GAGs) are covalently
bound. Proteoglycans contain a greater amount of carbohydrate than do glycoproteins.
•
B: Glycoproteins are globular protein molecules to which branched chains of monosaccharides are
covalently attached.
•
Transverse section of tongue. Immunocytochemical staining shows the distribution of laminin basement
membranes in epithelial layer, capillary blood vessels, nerve fibers, and striated muscle.
•
Electron micrograph of a fibrocyte in dense regular connective tissue. The sparse cytoplasm of the fibrocytes
is divided into numerous thin cytoplasmic processes that interdigitate among the collagen fibers. x25,000.
•
Reticular connective tissue showing only the attached cells and the fibers . Reticular fibers are enveloped by
the cytoplasm of reticular cells; the fibers, however, are extracellular, being separated from the cytoplasm
by the cell membrane. Within the sinuslike spaces, cells and tissue fluids of the organ are freely mobile.
•
Mucous tissue of an embryo showing fibroblasts immersed in a very loose extracellular matrix composed
mainly of molecules of the ground substances.
Membrane structure
Sheet-like arrangements of extracellular matrix protein External lamina ( muscle and nerous tissue )
The role of basement membrane is not well understood .
•
Attachment.
•
Selective filtration barrier.
•
Influence the differentiation and proliferation of the epithelial cells that contact it.
adipose tissue
•
•
•
Adipocytes :
o
Isolated
o
Small groups
o
Adipose tissue
Adipose tissue :
o
15-20% in men, 20-25% in women
o
Triglycerides – higher caloric value
o
Thermal insulation
o
Unilocular – common or yellow
o
Multilocular – brown
Stored fat within adipocytes is derived from
o
Dietary fat circulating
o
Triglycerides synthesized in the liver
o
Triglycerides synthesized from glucose
•
Unilocular – regulation,
•
Cells – spherical, polyhedral with eccentric and flattened nuclei
o
Signet ring
o
Connective tissue – rich vascular bed and network of nerves
o
Storage & mobilization of lipids
o
VLDL very low-density lipoproteins
Capillary endothelium – capillary basal lamina – connective tissue ground substance – adipocyte basal lamina
– adipocyte plasma membrane.
o
Synthesis fatty acids from glucose- insulin
o
Sex hormones, and glucocorticoids, growth hormone, prolactin, corticotropin, insulin, and thyroid
hormone.
o
Obesity
o
Lipoblasts
Multilocular adipose tissue
o
Hibernating animals – hibernating gland.
o
First months of postnatal life.
o
Cells – polygonal smaller, great number of lipid droplets, central nucleus.
o
Function – heat production, thermogenin
o
Develops – epithelium, endocrine gland.
Skeletal Tissues :introduction
Cartilage
Hyaline, Fibrous, Elastic
Bone
Woven, Lamellar, Compact, Cancellous
( Spongy )
Joints
Ligaments
Tendons









Cartilage : Is a semi-rigid form
Extracellular Matrix : Ground substance : Sulphated GAGs ( chondroitin sulphate, keratan sulphate ) +
hyaluronic acid
Fibres : Collagen and Elastic
Cells:
Chondroblasts synthesis of ground substance and fibrous extracellular material . Mitotic divisions to form
a small cluster of mature cells ( known as chondrocytes ).
Perichondrium : At the periphery of mature cartilage is a zone of condensed supporting tissue called
perichondrium containing chondroblasts with cartilage – forming potential .
Growth of cartilage :
Interstitial growth
Appositional growth
Most cartilage is devoid of blood vessels
Hyaline Cartilage
Most common type.
Nasal septum, larynx, tracheal rings, most articular surfaces and the sternal ends of the ribs
Small aggregation of chondrocytes embedded in an amorphous matrix of ground substance reinforced by collagen
fibres ( II )
Elastic Cartilage
External ear and external auditory canal , the epiglottis, part of the laryngeal cartilages and the walls of the
Eustachian tubes.
Numerous bundles of branching elastic fibres, collagen is also a major constituent of the cartilage matrix
Fibrocartilage is a combination of dense supporting tissue and cartilage.
Functions of bone tissue





Muscular insertion
Organism movement
Protection of important organs
Contain haemopoietic bone marrow
Storage of calcium and phosphate salts
Is composed of :
Extracellular calcified material
•
Ground substance
•
Fibres
Cells :
•
•
•
•
Osteoblasts : Synthesize osteoid and mediate its mineralisation Origin Osteoprogenitor cell Site Bone
surface
Osteocytes: Inactive osteoblasts , assist in nutrition of bone
Osteoclasts : Phagocystic cells
Origin Macrophage Site Howship’s lacunae
monocyte cell line
forming ruffled border
Have receptors for calcitonin, and thyroid hormone.
Osteoblasts have receptors for parathyroid hormone and, when activeted by this hormone, produce a
cytokine called OSF Osteoclast Stimulating Factor.
Extracellular matrix
•
Ground substance : organic matrix proteoglycans and a group of non-collagen molecules
osteocalcin, osteonectin, sialoproteins
50% inorganic salts: Calcium and Phosphate ( hydroxyapatite crystals ), Magnesium carbonate, sodium and
potassium ions .
Hydroxyapatite crystals Ca10(PO4)6(OH)2
•
Fibres : Collagen type I ( hole zones ) spaces within this three- dimensional structure, are the initial site of
mineral deposition.
Periosteum and Endosteum
•
Outer or inner surfaces
•
Condensed fibrous tissue
•
Osteoprogenitor cells
•
Periosteum is not present on the articular surfaces of bone , the sites of insertion of tendons and
ligaments
•
Repair of bone fractures
•
Failure of healing of subcapsular fractures of the femoral neck
Types of bone
•
compact bone
•
cancellous bone – spongy
•
Primary, immature, woven bone
•
Secondary, mature, lamellar bone
Compact bone is made up of parallel bony columns , which , in long bones, are disposed parallel to the long axis .
•
Lamellae ( 4-20 lamellae, each 3-7 μm )
•
Canals of Havers or Haversian canals – Haversian systems
•
Volkmann’s canals
•
Cell lacunae – canaliculi
•
Interstitial systems, outer and inner circumferential lamellae.
Cancellous ( spongy ) bone is composed of a network of bony trabeculae .
•
Irregular lamellae ( 100 – 200 µm )
•
Does not contain Haversian systems
•
Canaliculi and sinusoids in the marrow
•
Endosteum & osteoprogenitor cells
•
Intramembranous ossification
•
Endochondral ossification
Bone development is controlled by :
•
growth hormone, thyroid hormone & the sex hormones
Synovial joints
•
Fibrous capsule
•
Ligaments
•
Synovial fluid
Knee joint,
diarthroses
Shoulder joint,
Ball and Socket joint
Lower limb and the foot
Non-synovial joints : Limited movement
No free articular surfaces:
•
Dense fibrous tissue ( bones of the skull )
syndesmoses
•
Hyaline cartilage
synchondrosis
•
Fibrocartilage
symphysis
Fibrous joint – Sutures,
peg suture ( Gomphosis ),
Cartilaginous joints - synchondrosis ( hyaline ),
Fibrocartilaginous joints - Symphysis
Osseous joints - Synostosis
Nervous tissue
•
Most complex system for communication
o
100 milion neurons
o
1000 interconnection
 circuits
•
Principal function is to receive stimuli from the internal & external environments
Receive,
Analyze,
Integrate
Intercommunicating network of neurons
Synapses: Sites of intercommunication
Neurotransmitters: mediate neurone-to-neurone transmission, act as chemical intermediates between the
nervous system and effector organs : skeletal muscle, smooth muscle, cardiac muscle, myoepithelial cells and
exocrine glands
Impulse ( presynaptic cell ) electrical signal
( postsynaptic cell ) chemical signal
Neurotransmitteres ( acetylcholine , norepinephrine ): Amines, amino acids, small peptides
Pain, pleasure, hunger, thirst, and sex
Neuromodulators
Axosomatic ( axon + cell body )
Axodendritic ( axon + dendrite )
Axoaxonic ( axon + axon )
Central Nervous System ( CNS ):





Spinal cord
Medulla oblongata
Cerebellum
Pons
Brain ,Cerebral cortex
Peripheral Nervous System ( PNS )





Nerves
Ganglions
Spinal g.
Sympathetic g.
Parasympathetic g.
Somatic nervous system
•
Neurons
•
Glial cells
Autonomic nervous system
Stimuli altering electrical potentials
Neurons, muscle cells, some gland cells
Excitable or Irritable
Propagation ‫انتشار‬
nerve impulse
Two great classes of functions :
•
Stabilization of the intrinsic conditions
•
Stabilization of the organism within normal ranges and behavioral patterns
Development of nerve tissue
•
Ectoderm
•
Notochord
•
Neural plate, neural groove, neural tube ( CNS )
•
Neural crest ( PNS ) : Adrenal medulla, melanocytes, odontoblasts, cells of the pia mater, and the
arachnoid, sensory neurons ( cranial and spinal sensory ganglia ), postganglionic neurons of sympathetic
and parasympathetic ganglia, Schwann cell of peripheral axons, Satellite cell of peripheral ganglia
Neurons
•
Large cell body - nucleus + perikaryon
•
Single process = axon
•
One or more processes = dendrites
Axon is a single cylindrical process up to 1 meter terminating on other neurones or effector organs ( terminal
boutons ) , axon hillock – cone-shaped portion of the cell body
Axon
axolemma ,
axoplasm
Dendrites are highly branched processes, specialized sensory receptors, major sites of information input into the
neurone
Dendrites - afferent
Cell bodies: 4 - 150 μ m
•
Spherical
•
Ovoid
Axons - efferent
•
Angular
Motor efferent, Sensory afferent
Multipolar neurone
Bipolar neurone
Pseudo-unipolar neurone
•
Cell body
•
Euchromatic nucleus with nucleolus
•
Rough endoplasmic reticulum + numerous polyribosomes
•
Rough endoplasmic reticulum + free ribosomes ( Nissl bodies )
•
Golgi complex, mitochondria, neurofilament, lipofuscin ( pigments )
-- perikaryon
Stain methods: 1- H&E huge nuclei, 2- Heavy metal impregnation technique Gold method , Tiny terminal boutons
3- The Nissl method stains RNA
Central Nervous System ( CNS )
Spinal cord
Medulla oblongata
Cerebellum
Pons
Brain ,Cerebral cortex
to describe arrangements of neurones and their connections
Spinal cord
Central
GRAY MATTER
anterior horns ( motor neurons ) ventral roots
roots
Peripheral
Cervical ns.
WHITE MATTER
8 pairs
‫رقبي‬
Thoracic ns. 12 pairs
‫صدري‬
Lumbar ns.
5 pairs
posterior horns ( sensory neurons ) dorsal
‫قطني‬
Sacral ns.
5 pairs
‫عجزي‬
Coccygeal n. 1 pair
‫عصعصي‬
Cerebellar cortex
three layers
GRAY MATTER
outer – molecular L.
central – Purkinje cells
inner – granule L.
Central regions
WHITE MATTER
Purkinje cell
•
conspicuous cell body
•
dendrites – highly developed ( molecular L. )
•
sparseness of nuclei
Cerebral cortex
•
GRAY MATTER
six layers of cells
•
afferent ( sensory ) impulses\
•
efferent ( motor ) impulses ( voluntary movements )
•
Central regions
Neurone types
Pyramidal cells ( Betz cells )
Stellate cells
Cells of Martinotti
fusiform cells
Horizontal cells of Cajal
WHITE MATTER
Layers of the neocortex
1. Plexiform l.
2. Outer granular l.
3. Pyramidal cell l.
4. Inner granular l.
5. Ganglionic l.
6. Multiform cell l.
Myelinated & unmyelinated nerve fibers
Schwann cells provide structural & metabolic support
Fibres are enveloped :
•
by the cytoplasm of Schwann cells
•
concentric layers of myelin sheath
•
Peripheral nerves
•
Contain any combination of afferent or efferent
•
nerve fibres of either the somatic or autonomic nervous systems.
Endoneurium : loose vascular supporting tissue
Perineurium : condensed layer of robust collagenous
tissue invested by a layer of flat epithelial cells
Epineurium : dense connective collagenous tissue
Ganglions – ganglia
Sensory :
Cranial
Spinal
Small glial cells : satellite cells
Autonomic ganglia:
Intramural ganglia, digestive tract, multipolar neurons.
Spinal g. :
On the posterior nerve roots of the spinal cord
Sympathetic g.:
cells are multipolar , numerous axons & dendrites
eccentrically nuclei , lipofuscin granules
Parasympathetic g. :
located within or near the effector organs
Autonomic nervous system
•
Control of smooth muscle
•
Secretion of some glands
•
Modulation of cardiac rhythm
•
Homeostasis
All the preganglionic fibers ( cholinergic )
Postganglionic parasympathetic .
Smooth muscles , heart, exocrine glands.
Muscle Tissue
Specialised contractile cells - Motile forces
( contractile proteins -actin and myosin )
Contractile units
Single-cell
Multicellular
•
Myoepithelial cells
•
Pericytes
Smooth muscle
•
Myofibroblasts
Cardiac muscle
Skeletal muscle
muscle cell organelles
Plasma membrane or plasmalemma = sarcolemma
Cytoplasm = sarcoplasm
Endoplasmic reticulum = sarcoplasmic reticulum
Skeletal muscle : Voluntary M., Striated M.
Very long, cylindrical, multinucleated cells, cross-striations, Contraction is quick, forceful.
Cardiac muscle : Involuntary M.
Elongated, branched individual cells, Intercalated dicks, Continuous , vigorous , rhythmic contractility of the heart
Smooth muscle : Involuntary M., Visceral M.
Collections of fusiform cells, no cross-striations
Skeletal muscle
•
Wide variety of morphological forms & modes of action
•
Muscle fibres –elongated, multinucleate contractile cells, bound together by collagenous supporting
tissue.
•
Contraction is controlled by large :
•
Motor nerves – motor unit ( vitality of skeletal muscle fibers )
•
Is specialized for relatively forceful contractions of short duration and under fine voluntary control
•
Dark band ( A band )
Light band ( I band )
‫متباين الخواص‬
Isotropic ‫متساوي الخواص‬
•
Anisotropic
•
Myosin
Actin
•
Hanzen’s band
Z band or Amici b.
•
M band
The conducting system for contractile stimuli
•
Synchronous contraction
•
Tubular extensions into the muscle cell , around each myofibril
•
T system with the extracellular space
•
Between the T tubules – sarcoplasmic reticulum forms terminal cisternae
•
Triad = terminal cisterna + T tubule + terminal cisterna
•
Calcium ions activate the sliding filament mechanism
Mechanism of contraction
•
increase in the amount of overlap between the filaments.
System of energy production
•
Fatty acids + glucose
•
Glycogen 0.5 -1%
•
Classification of muscle fibers:
•
Type I – myoglobin , continuous contraction, fatty a.
•
Type II – rapid discontinuous contraction, less myoglobin
•
Type II, IIA, IIB, and IIC .
Cardiac muscle
Involuntary M. rhythmic contractility of the heart
Contractions are:
•
strong & utilize a great deal of energy
•
continuous
•
modulated by external autonomic & hormonal stimuli
Cardiac muscle fibres are cylindrical cells with one or two nuclei
Intercalated discs ( syncytium )
There are three junctional specializations :
1. Fasciae adherentes ‫ – صفاق الصق‬anchoring sites for actin
2. Maculae adherentes ( desmosomes )
3. Gap junctions- ionic continuity
Between the muscle fibers collagenous tissue analogous to the endomsyium
Contractile proteins similar to that of skeletal muscle
T system
Diads – one T tubule and one sarcoplasmic reticulum cisterna
The T tubules are mor numerous and larger in ventricular muscle.
Mitochondria – 40% of cytoplasmic volume
2% of skeletal muscle fibers
Fatty acids – triglycerides
Glycogen – energy production during periods of stress
Differences between atrial and ventricular muscle
Fewer T tubules
Cells are smaller
Membrane-limited granules- most abundant in Right Atrium ( atrial natriuretic factor ) , acts on the kidneys to
cause sodium and water loss. ( natriuresis, and diuresis ) ‫ غزارة البول إدرار‬opposes aldosterone & antidiuretic
hormone , sodium and water conservation.
Smooth muscle : Involuntary M., Visceral M.
•
Is specialised for continuous contractions of relatively low force .
•
Influences of the autonomic nervous system, hormones & local metabolites .
•
Elongated spindle-shaped ( fusiform )cells with one central elonga-ted nucleus.
•
The contractile proteins of smooth muscle are not arranged in myofibrils ( not striated ).
•
The contractile proteins are arranged in a crisscross.
•
Smooth muscle is able to maintain a high force of contraction for very little ATP usage.
•
Desmin & vimentin.
•
smooth muscle receives both adrenergic and cholinergic nerve endings.
•
Smooth muscle cells synthesize collagen, elastin & proteoglycans.
regeneration
•
Cardiac muscle no regenerative capacity
•
Skeletal muscle – limited regeneration , satellite cells.
•
Smooth muscle - active regenerative response.
Blood
Different cells ,
red
erythrocytes
white leukocytes
platelets
thrombocytes
Fluid medium – Plasma
Plasma proteins + inorganic salts
Hematocrit –
40-50% men
35-45% women
volume of packed erythrocytes per unit volume of blood.
Lower layer – 42-47% erythrocytes
Buffy coat –
1%
leukocytes
Buffy coat – White or grayish.
Blood - functions
Transport of : 1 gases, O2, CO2
2 nutrients,
3 metabolic waste products,
Red blood cells - ERYTHROCYTES
White blood cells - LEUKOCYTES
•
ERYTHROCYTES – transport of oxygen and carbon dioxide
•
LEUKOCYTES – defense and immune systems
•
PLATELETS – control of bleeding ( haemostasis )
4 cells and hormones
Platelets - THROMBOCYTES
Blood Plasma: Translucent, yellowish, somewhat viscous supernatant.
Roles: regulation of body temperature
acid-base and osmotic balance
•
90% water , 7% proteins, 3% lipids + carbohydrates + inorganic salts 0.9%, amino acids, vitamins,
hormones.
Staining of blood cells:
Smear
Mixtures of red ( acidic ) and blue ( basic ) dyes.
Azures – azurophilics
Giemsa
Wright’s
Leishman’s
Erythrocytes
are highly adapted for its function of Oxygen and Carbon dioxide transport
•
anucleate , without cytoplasmic organelles , Biconcave disks, quite flexible – adapt to the small
diameters of capillaries.
•
Cuplike shape, ( HbA – normal adult , easily deformed).
•
diameter 7.5 μm ( smallest capillaries 3 - 4 μm )
•
2.6 μm thick ( rim ) – 0.8 μm thick ( center )
•
number ♂ 4.1 – 6 million /mm3 ♀ 3.9 – 5.5 million /mm3
lifespan 120 days
Decreased number
anemia
Increased number
erythrocytosis, polycythemia
physiological adaptation – high altitudes
increases blood viscosity
•
Diameters
greater than 9 μm
macrocytes,
less than 6 μm microcytes
Anisocytosis : great variations in size of erythrocytes
Reticulocytes – younger erythrocytes, 1% of the total number.
( few granules, or a netlike structure )
increased number – hemorrhage, recent ascent to high altitude ...
Plasmalemma
Hemoglobin + O2
Hemoglobin + CO2
Oxyhemoglobin
Carbaminohemoglobin
reversible
Hemoglobin + CO
Carboxyhemoglobin
irreversible
Glucose / anaerobically degrade – source of energy
Do not synthesize hemoglobin
Removed by macrophages – spleen, bone marrow
Haemoglobin - ♂ 15 – 18 g\100 ml
♀ 14,5 g\100 ml
Haemoglobin
•
anemia
aggregation O, A, B, AB
globular sedimentation
White blood cells - LEUKOCYTES
Migrate to the tissues. Most die by appotosis
Five types in the circulation . These are divided into two main groups :
Granulocytes
Polymorphonuclear
Agranulocytes
Mononuclear
•
Neutrophils
Monocytes
•
Eosinophils
Lymphocytes
•
Basophils
•
Granulocytes
•
Specific granules, neutral – basic – acidic
•
Azurophilic granules ( lysosomes )
•
Nuclei – 2 and more lobes
•
Lifespan – few days (billions of neutrophils die )
•
•
removed by macrophages without inflammatory response
Do not synthesize much protein
•
Golgi c., RER – poorly developed.
•
Few mitochondria ( low energy metabolism )
•
Contain glycogen, Golgi complex, rough endoplasmic reticulum
Agranulocytes
•
Do not have specific granules.
•
Azurophilic granules ( lysosomes )
•
Nuclei – round or indented
•
Leukocytes leave the venules and capillaries by diapedesis
•
Lymphocytes recirculate
•
Chemotaxis – attraction of specific cells by chemical mediators
•
Number of leukocytes varies according to age, sex, physiologic conditions
Neutrophils
•
Most common type , 60-70%
•
( 2 - 5 ) 3 – lobes, with fine threads of chromatin, Barr body 3% drum-stick like appendage ( inactive X
chromosome )
•
Short-lived cells , half-life 6-7 hours ( blood )
1-4 days ( connective T. )
•
Principal function in acute inflammation
•
Highly motile & phagocytic, active ameboid movement.
Phagocytes of bacteria and other small particles.
Eosinophils
•
2- 4% , diurnal variation
•
Bilobed nucleus
•
Majority enter the skin, pulmonary or gastrointestinal mucosae , May migrate into local secretions
•
Lifespan ?
•
Eosinophilia – helminthic ( parasitic ) infections, allergic reactions
•
Diameter 12-17 μm
•
Phagocytose antigen-antibody complexes.
Effect of corticosteroids.
Basophils
•
Less 1%
•
Similarities with tissue mast cells, but they originate from different stem cells in the bone Marrow.
•
irregular lobes nucleus
•
Diameter 12-15 μm
•
Granules are highly soluble in water
•
Heparin, & histamine ,
•
Slow Reacting Substance of Anaphylaxis ( SAS-A )
•
Metachromasia-
Immediate hypersensitivity reactions
Monocytes
•
largest
•
2 – 10 %
•
bone marrow derived
•
highly motile and phagocytic
•
eccentrically placed oval, horseshoe, kidney shaped nucleus , 2 or more nucleoli
•
Monocytes-macrophage system
MACROPHAGES
Lymphocytes
•
smallest
•
20 – 50 %
•
central role in all immunological defence mechanisms
•
round dense nucleus , non-granular cytoplasm
•
Lifespan ? Few days – many years
•
Diameter 6- 9 μm , 9-15 μm , 18 μm
•
Natural killer cells
Platelets - THROMBOCYTES
•
Small, non-nucleated cells, disklike cell
•
2 to 4 μm
•
200,000 to 400,000 /ml.
•
Central granular cytoplasm , peripheral poorly stained cytoplasm
•
Lifespan 10 days
•
Megakaryocytes
•
Hyalomere – peripheral light blue,
•
Granulomere – central zone ( purple granules )
•
Marginal bundles of microtubules
Actin + myosin ( hyalomere )
•
Functions :1- form plugs to occlude sites of damage
2- promote clot formation
3- secrete factors ( vascular repair )
•
Primary aggregation- platelets plug
•
Secondary aggregation- adhesive glycoprotein
•
Blood coagulation- clot retraction
•
Clot removal ( plasmin- plasminogen, plasminogen activators – endothelial cells )
Circulatory system
Blood Vascular S.
Lymph Vascular S.
Mediates the continuous movement of all body fluids
Transport of O2 ,
nutrients
CO2 , metabolic waste products
to
the tissues
from
the tissues
Temperature regulation , Distribution of hormones & cells
Basic structure
Endothelium
smooth muscles
vasa vasorum
Endothelium
Smooth muscles
Vasa vasorum
Endocardium
Myocardium
Epicardium
HEART
Cardiac muscle, Striated Involuntary M.
Visceral pericardium
Parietal pericardium
Specialised conducting system
•
Sinoatrial node
•
Atrioventricular node
•
Atrioventricular bundle or bundle of His
Purkinje fibres
The arterial system
Elastic arteries
Muscular arteries
The microcirculation
Capillaries
•
Diameter 3 – 4, 30 – 40 μm sinusoids
•
Capillary endothelium :
•
Continuous C.
•
Fenestrated C.
•
Discontinuous E.
•
Arteriovenous shunts ‫تحويلة أو وصلة‬
•
Abundance of the capillary network
The venous system
Arterioles
Gastrointestinal tract
Ingestion ,
Fragmentation ,
Digestion ,
Absorption and elimination of waste products
Oesophagus , stomach , small intestine ( duodenum , jejunum, ileum ), large intestine (caecum - appendix,
ascending, transverse, descending and sigmoid colons ), rectum and anal canal
Basic structure
Mucosa
Epithelium, lamina propria
Muscularis mucosae
Thin smooth muscle layer
Submucosa
Loose collagenous T., blood vessels, lymphatics and nerves
Muscularis propria
Smooth muscles : inner circular, outer longitudinal layers ( inner oblique layer )
Adventitia
Loose supporting tissue , major vessels & nerves
Epithelium
Protective,
Secretory,
Absorptive,
Absorptive / protective
Stomach: Cardia,
Corpus or body of stomach
Pylorus
Fundus
Hydrochloric acid
pH 0.9 – 1.5 + pepsin
Gastric glands
Surface mucous cells – Microvilli , secrete protective bicarbonate ions
Parietal or oxyntic cells
( isthmus ) secrete gastric acid + intrinsic factor ( absorption B12 )
Neck mucous cells
Chief, peptic or zymogenic cells Pepsin
Neuroendocrine cells – serotonin
Stem cells – in the neck.
Gastrin
D cells – somatostatine
A cells – glucagon
Lymphoid follicles are not found in normal gastric mucosa
Small intestine
Duodenum ‫العفج‬
Jejunum
‫الصائم‬
Ileum
‫الدقاق‬
Mucous Membrane:
•
Simple columnar cells
•
Goblet cells ( few )
•
Secretory cells :
1. Secretin – duodenum, jejunum
2. Glucagon - ileum
3. Serotonin
4. Peptide anti-gastrin - duodenum
 Enterocytes
 Goblet cells
 Paneth cells
 Neuroendocrine cells
 Stem cells
 Intraepithelial lymphocytes

Large intestine
1. Colons
2. Don’t have villi
3. Numerous of Lieberkühn glands
4. Muscularis mucosae
5. Muscularis propria is thick

Appendix
1. Small blind-ended tubular sac extending from the caecum
2. Digestion of cellulose
3. Lieberkühn glands are short
4. Lymphatic follicles are big

Rectum & recto-anal junction
1. Columns of Morgagni
2. Voluntary muscle – anal sphincter
Liver
Biggest gland : 1.5 kg, 4 lobules,
Specific capsule
Bile ducts , Portal vein , Hepatic artery,
Central vein , Sinusoids
Liver functions
•
Detoxification of metabolic waste products
•
Destruction of spent red cells
•
Synthesis and secret of bile
•
Synthesis of the plasma proteins
•
Synthesis of plasma lipoproteins
•
Metabolic functions, storage of glycogen and Fe
•
Detoxification of drugs and toxins
•
Secret of urea
‫‪Synthesis of antibodies‬‬
‫•‬
‫المعثكلة‬
‫•‬
‫القسم داخلي اإلفراز ‪ :‬جزيرات النغرهانس‬
‫•‬
‫مجموعات خلوية موزعة في الغدة ‪ :‬خاليا صغيرة مضلعة غير واضحة الحدود نواها مركزية ‪:‬‬
‫‪Pancreas‬‬
‫•‬
‫خاليا ألفا‬
‫•‬
‫خاليا بيتا مفرزة لألنسولين‬
‫•‬
‫خاليا ‪ C‬احتياطية‬
‫•‬
‫خاليا ‪D‬‬
‫مفرزة للغلوكاغون‬
‫مفرزة للسوماتوستاتين‬
‫‪Islets of Langerhans‬‬
‫•‬