introduction to human tissues #3
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Introduction to Human Tissues #3. Laura Fraser Cotlin, Ph.D. Fundamentals 2 – Dental/Optometry November 2, 2011. Classification of Connective Tissues. Embryonic connective tissues 1. Mesenchymal 2. Mucous Connective tissue proper 1. Loose (areolar) 2. Dense - PowerPoint PPT PresentationTRANSCRIPT
Introduction to Human Tissues #3
Laura Fraser Cotlin, Ph.D.
Fundamentals 2 – Dental/Optometry
November 2, 2011
Classification of Connective Tissues
Embryonic connective tissues1. Mesenchymal
2. Mucous
Connective tissue proper1. Loose (areolar)2. Dense
a. Dense irregularb. Dense regular
-collagenous-elastic
Specialized connective tissue1. Cartilage2. Bone3. Blood4. Adipose
Adipose Tissue
Adipocytes-involved in energy storage, insulation, cushioning of organs and secretion of hormones- Large cells, can be up to ~100um- Lipid mass is not membrane bound- White (unilocular) or brown (multilocular)
Hormones involved in short-term weight controlghrelin – stimulates appetitePeptide YY – induces sense of fullness
Hormones involved in long-term weight controlleptin – produced exclusively by adipocytes.
-generally thought to reduce appetite (obese people have high levels and are thought to be resistant to leptin action)insulin – enhances conversion of glucose into triglycerides
Fat absorption and release
White Adipose Tissue
Blood
The hematocrit of human blood
-volume of cells and plasma is ~45 and 55% respectively
-Hematocrit - volume of packed erythrocytes in a sample of blood
Normal hematocrit~39-50% in males~35-45% in females
Leukocytes and platelets constitute only ~1% of blood volume
Composition of Whole Blood
Fluid is called PLASMA occupies ~55% of the total blood volume liquid extracellular material
Plasma that lacks coagulation (clotting factors) is called SERUM.
Cartilage
CARTILAGE Specialized connective tissue, part of skeletal
systemFunctions: provide flexible support (bone rigid
template for bone formationLocations: limited sites – respiratory system,
joints, external ear
Composition: cells + matrix (properties from matrix) 1. Matrix: a. Fibers: collagen II, elastic fibers b. Ground substance: proteoglycans
and glycosaminoglycans (GAGs) 2. Cells: chondroblasts, chondrocytes,
c
b
dc
a
FEATURES OF CARTILAGE
• CARTILAGE IS A SHOCK ABSORBER• Add pressure: water forced out of tissue, absorbs
pressure• Release pressure: water rebinds PG aggregate and tissue
returns to original size
• Avascular• No nerves• No lymphatics
Perichondrium
Isogenous group Chondrocyte in lacuna
Territorial matrix around chondrocytes
Interterritorial matrix between isogenous groups or single cells.
Chondrocytes in association with
Matrix
TYPES OF CARTILAGE
1. Hyaline: most common – nasal septum, joint surface, ribs
2. Elastic: enriched with elastic fibers – ear, larynx-Looks like hyaline cartilage with the addition of elastic fibers
between cells
3. Fibrocartilage: found in interverterbral disks, tendon/ligament attachment.
-See rows of chondrocytes with increased fibrous matrix between between them
Hyaline Cartilage
Elastic Cartilage
Fibrocartilage
Bone Tissue
FUNCTIONS OF BONE1. Support2. Protection (skull)3. Locomotion4. Calcium store (also Mg and Na)5. Hematopoiesis (marrow)
TYPES OF MATURE BONECancellous (spongy): fine irregular plates – trabeculae
inside long bones (marrow) gives strength without
weight
Compact: highly orderedTypes: outer and inner circumferential lamellae-contains Haversian systems (osteons)
COMPOSITION OF BONE: cells + matrixMatrix1. Organic a) fibers: type I collagen, highly organized b) ground substance: little, some PG as
cartilage 2. Inorganic: Calcium phosphate complexes forms 50%
of the matrix, giving the material its rigidity
***Bone looks solid but is alive, dynamic and continually remodeling.
***Is highly vascularized (compared to cartilage)
PRIMARY CELLS IN BONE1. Osteoblasts: immature, synthesize and secrete
osteoid, which becomes mineralized to give bone; do not divide.
2. Osteocytes: surrounded by matrix, maintain matrix; do not divide.
3. Osteoclasts: large multinucleate cells, resemble macrophage in function, remodel bone by resorbing bone matrix.
Main cells include:-Osteoblast-Osteocyte-Osteoclast
Bone Cells
EPIPHYSIS
DIAPHYSIS
EPIPHYSIS
Articular cartilageCancellous bone Compact bonePeriosteumMarrow cavity
Compact (Ground) Bone
Spongy Bone
(intermembrane
ous)
Muscle Tissue
Types of Muscle Tissue
Common Features of ALL MUSCLE TISSUE
Derived from mesoderm layer Cell membrane = sarcolemma Cytoplasm = sarcoplasm ER = sarcoplasmic reticulum (SR)
Contraction of all muscle depends on the interaction of actin and myosin
Contraction of all muscle is regulated by cellular calcium
Skeletal Muscle Tissue
bundles of very long, cylindrical multinucleated cells showing cross striations.
contraction is quick, forceful --> caused by interactions of thin actin filaments and thick myosin filaments.
Cell size: length can be up to ~3cm
diameter ranges 10-100um
Associated Connective Tissue Epimysium - dense connective tissue surrounding the entire
muscle. Perimysium - connective tissue surrounding the bundles of
fibers within a muscle. Endomysium – basement membrane and delicate connective tissue
surrounding each muscle fiber
Structure of Skeletal Muscle Tissue
Long. section of Skeletal Muscle
EM of Striated Muscle
The Sarcomere –extends from Z-line to Z-line-the smallest repetitive subunit of the contractile unit
Arrangement of Thick and Thin Filaments
Sarcomeres at different functional
stages
Neuromuscular Junction
Cardiac Muscle Tissue
Cardiac Muscle Tissue heart muscle consists of tightly knit bundles of cells which provide
for a characteristic wave of contraction that leads to a wringing out of the heart ventricles.
exhibit a cross-striated banding pattern identical to that of skeletal muscle.
structure and function of the contractile proteins are almost the same as in skeletal muscle.
distinguishing characteristic is the presence of intercalated disks - dark-staining transverse lines that cross the chains of cardiac cells at irregular intervals.
EM of cardiac muscle tissue
Structure of the Intercalated Disk
Long. section of Cardiac Muscle
Smooth Muscle Tissue
Smooth Muscle Tissue composed of elongated, nonstriated cells
Cells are enclosed by a basal lamina and network of reticular fibers these 2 components serve to combine the forces generated by each
smooth muscle fiber into a concerted action.
cells are fusiform (largest at midpoint and tapered at the ends) with a single centrally-located nucleus
tight packaging of tissue is achieved by lining up cells with the narrow parts of some cells against the broad parts of neighboring cells.
the cell boarders become scalloped when contracted, and the nucleus becomes folded or has a cork-screw appearance.
Smooth Muscle Tissue composed of elongated,
nonstriated, fusiform cells(largest at midpoint and tapered at the ends)
tight packaging of tissue is achieved by lining up cells with the narrow parts of some cells against the broad parts of neighboring cells.
Contain dense bodies for attachment of filaments and propagation of contraction.
Nerve Tissue
ORGANIZATION OF NERVOUS
SYSTEM
Can be divided into:-the somatic nervous system-the autonomic nervous system
-sympathetic division-parasympatheic division-enteric division
Components include:-cranial nerves-spinal nerves-peripheral nerves-ganglia
-somatic or sensory - dorsal root ganglia-autonomic sympathetic, parasympathetic, enteric
-specialized nerve endings
Peripheral Nervous System
Types of Neurons
Can be classified based on:
-morphology-function-neurotransmitters
Organization of a
Typical Neuron
From Junqueira and Carneiro. McGraw-Hill Publishing, 2005
Nerve Organization
From Junqueira and Carneiro. McGraw-Hill Publishing, 2005