Exercise 7 animal tissues

Biology 101 Laboratory September 2009

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EXERCISE VIEXERCISE VIEXERCISE VIEXERCISE VI HISTOLOGYHISTOLOGYHISTOLOGYHISTOLOGY

TissueTissueTissueTissue

• group or aggregation of cells

• display common functional or morphological properties or both

HistologyHistologyHistologyHistology

• study of microstructure of tissues

4 Major Types of Tissues4 Major Types of Tissues4 Major Types of Tissues4 Major Types of Tissues 1. Epithelial Tissues 2. Connective Tissues 3. Muscular Tissues 4. Nervous Tissues

I. I. I. I. EPITHELIAL TISSUESEPITHELIAL TISSUESEPITHELIAL TISSUESEPITHELIAL TISSUES � Covers external surfaces of the body or lines cavities � Lacks vascular supply but are nourished by diffusion from capillary beds in the underlying CT � Derived from the three embryonic layers � For protection; secretion, absorption, lubrication & sensory perception

Basal membrane/Basal laminaBasal membrane/Basal laminaBasal membrane/Basal laminaBasal membrane/Basal lamina – thin membrane that bounds the epithelial tissues to the underlying connective tissues

According to Shape:According to Shape:According to Shape:According to Shape: 1. Squamous 2. Cuboidal 3. Columnar

According to Number of Cell Layers:According to Number of Cell Layers:According to Number of Cell Layers:According to Number of Cell Layers: 1. Simple 2. Stratified 3. Pseudostratified 4. Transitional

Simple Squamous EpitheliSimple Squamous EpitheliSimple Squamous EpitheliSimple Squamous Epitheliumumumum Source: inner lining of cheek

Simple Cuboidal EpitheliSimple Cuboidal EpitheliSimple Cuboidal EpitheliSimple Cuboidal Epitheliumumumum Source: kidney tubules


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Simple Columnar Simple Columnar Simple Columnar Simple Columnar EpitheliumEpitheliumEpitheliumEpithelium Source: stomach or small intestine

• highly absorptive surfaces → small intestine

• secretory surfaces → stomach

• may be specialized for secretion → goblet cells in the small intestine

Stratified Squamous EpitheliumStratified Squamous EpitheliumStratified Squamous EpitheliumStratified Squamous Epithelium Source: skin

• Composed of epithelial tissues with more cell layers • Only cells of the lowest layer touch the basement membrane • Basal layer consists of columnar or cuboidal cells → undergoes continuous mitotic division

• Cells near the surface are flattened, consists of squamous cells

Pseudostratified Ciliated Columnar EpitheliumPseudostratified Ciliated Columnar EpitheliumPseudostratified Ciliated Columnar EpitheliumPseudostratified Ciliated Columnar Epithelium Source: trachea

• ‘pseudo’ → false

• Cells appear to be arranged in more than one layer but all of them are attached to the basal membrane, thus are actually single layer of cells

• Pointed structure: microvilli (hair-like structures)


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Transitional EpitheliumTransitional EpitheliumTransitional EpitheliumTransitional Epithelium Source: urinary bladder

• Transition between stratified squamous & columnar epithelium • Cells change their form • Found in hollow organs subject to contraction & stretching

II. II. II. II. CONNECTIVE TISSUESCONNECTIVE TISSUESCONNECTIVE TISSUESCONNECTIVE TISSUES

� Bind, anchor, and support body parts � Abundant cellular matrix � Originate from the mesenchymemesenchymemesenchymemesenchyme, the embryonic connective tissue that develops from the mesodermmesodermmesodermmesoderm � 2 Types:

1. Connective Tissue ProperConnective Tissue ProperConnective Tissue ProperConnective Tissue Proper – for binding organs 2. Specialized Connective TissuesSpecialized Connective TissuesSpecialized Connective TissuesSpecialized Connective Tissues – binding & other specific functions

� Connective tissue fibers: 1. Collagen fibersCollagen fibersCollagen fibersCollagen fibers – thick, un-branched, appear wavy; show resistance to stretching 2. Elastic FibersElastic FibersElastic FibersElastic Fibers – thin & less wavy than collagen fibers, branched; easily stretched but return to

normal length when tension is released 3. Reticular FibersReticular FibersReticular FibersReticular Fibers – extremely fine & highly branched forming network

Connective Connective Connective Connective Tissue ProperTissue ProperTissue ProperTissue Proper Loose or Areolar Connective TissueLoose or Areolar Connective TissueLoose or Areolar Connective TissueLoose or Areolar Connective Tissue

• Large amount of tissue fluid, many cells, few fibers

Dense Connective Tissue (Tendon)Dense Connective Tissue (Tendon)Dense Connective Tissue (Tendon)Dense Connective Tissue (Tendon)

• More fibers, less ground substance & cells


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Specialized ConSpecialized ConSpecialized ConSpecialized Connective Tissuenective Tissuenective Tissuenective Tissue:::: Adipose TissueAdipose TissueAdipose TissueAdipose Tissue

• Store fats in the form of triglyceridestriglyceridestriglyceridestriglycerides

• Stores nutrients, provides insulation, & acts as cushion; fills crevices in organs

• AdipocytesAdipocytesAdipocytesAdipocytes → fat cells

CartilageCartilageCartilageCartilage

• Soft & pliable • ChondrocytesChondrocytesChondrocytesChondrocytes → cartilage cells

• Lacuna → cartilage matrix

• The lacuna houses the chondrocytes

3 Types of Cartilage based on Matrices: 3 Types of Cartilage based on Matrices: 3 Types of Cartilage based on Matrices: 3 Types of Cartilage based on Matrices:

1. Hyaline Cartilage 2. Elastic Cartilage 3. Fibrocartilage

Hyaline Cartilage:Hyaline Cartilage:Hyaline Cartilage:Hyaline Cartilage: Source: trachea

• Clear homogenous matrix • PerichondriumPerichondriumPerichondriumPerichondrium → dense connective tissue at the periphery of the cartilage

• Spindle-shaped lacunae

Elastic CartilageElastic CartilageElastic CartilageElastic Cartilage Source: epiglottis & external ear

• Contains collagen fibers, & a network of elastic fibers

FibrocartilageFibrocartilageFibrocartilageFibrocartilage

• Resembles connective tissue proper • Consists of a network of collagen fibers • Lacunae → round or oval


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Specialized Connective TissueSpecialized Connective TissueSpecialized Connective TissueSpecialized Connective Tissue (continuation) BoneBoneBoneBone

� For support, protection, movement, forming blood cells; reservoir of calcium

� Lamellae → matrix � Haversian canal � OsteocytesOsteocytesOsteocytesOsteocytes → bone cells � Lacunae � Canaliculi → minute canals radiating from the lacunae � Haversian SystemHaversian SystemHaversian SystemHaversian System or OsteoneOsteoneOsteoneOsteone – composed of haversian canal, lamellae, osteocytes, lacunae, & canaliculi

� Volkman’s canalVolkman’s canalVolkman’s canalVolkman’s canal – canals that runs diagonally/right angles to the Haversian canal

BloodBloodBloodBlood � Transport medium � Consists of cells, matrix, & intercellular fibers � Cellular elements: erythrocytes, leucocytes, & thrombocytes � Matrix: liquid called plasmaplasmaplasmaplasma � Function: transporting gases & substances to and from the different parts of the body

1.1.1.1. Erythrocytes or Red Blood CellsErythrocytes or Red Blood CellsErythrocytes or Red Blood CellsErythrocytes or Red Blood Cells � Oxygen carrier � carries hemoglobin

2.2.2.2. Leucocytes or White Blood CellsLeucocytes or White Blood CellsLeucocytes or White Blood CellsLeucocytes or White Blood Cells � For body defense against microorganisms by their phagocytic action & antibody production

a.a.a.a. Granular WBCGranular WBCGranular WBCGranular WBC ♦ have a granulated cytoplasm & multi-lobulated nucleus connected by chromatin strands ♦ function as phagocytesphagocytesphagocytesphagocytes

b.b.b.b. Agranular WBCAgranular WBCAgranular WBCAgranular WBC ♦ cells without granules in the cytoplasm ♦ are transformed into large phagocytic cells called macrophagesmacrophagesmacrophagesmacrophages

3.3.3.3. PlateletsPlateletsPlateletsPlatelets � also, thrombocytesthrombocytesthrombocytesthrombocytes � small, non-nucleated, colorless, round or oval, non-motile corpuscles functionally related to blood clotting

Human RBC Human RBC Human RBC Human RBC Frog’s RBCFrog’s RBCFrog’s RBCFrog’s RBC

Granulated WBC Granulated WBC Granulated WBC Granulated WBC Agranulated WBCAgranulated WBCAgranulated WBCAgranulated WBC


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III. MUSCLE TISSUESIII. MUSCLE TISSUESIII. MUSCLE TISSUESIII. MUSCLE TISSUES

• specialized for contraction

• contains contractile proteins – allows them to shorten their lengths

• muscle cells → muscle fibers

• 3 Types of Muscle Tissues:3 Types of Muscle Tissues:3 Types of Muscle Tissues:3 Types of Muscle Tissues: 1. Skeletal muscle 2. Smooth muscle 3. Cardiac muscle

Skeletal MuscleSkeletal MuscleSkeletal MuscleSkeletal Muscle

• connected to the skeleton • concerned with body movement • striated; voluntary in action • skeletal muscle cells: cylindrical, striated & multinucleated; oval nuclei are at the periphery of the cell • FasciculiFasciculiFasciculiFasciculi – muscle fibers grouped into bundles

• EndomysiumEndomysiumEndomysiumEndomysium – connective tissue meshwork enveloping the muscle fiber

• PerimysiumPerimysiumPerimysiumPerimysium – connective tissue sheath joining the fasciculi

• EpimysiumEpimysiumEpimysiumEpimysium – holds together the whole muscle mass

Smooth MuscleSmooth MuscleSmooth MuscleSmooth Muscle

• found as part of the walls of the viscera (internal organs) • non-striated; involuntary in action • smooth muscle cell: spindle-shaped cells in side view with a single centrally located nucleus at the widest part of the cell

• cytoplasm is homogenous


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Cardiac MuscleCardiac MuscleCardiac MuscleCardiac Muscle

• comprises the contractile wall of the heart; also found in the roots of large blood vessels arising from the heart

• specialized to contract automatically & rhythmically • striated, branched; involuntary in action • presence of intercalated discs → dark bands

IV. NERVOUS TISSUESIV. NERVOUS TISSUESIV. NERVOUS TISSUESIV. NERVOUS TISSUES

• specialized to receive stimuli from the environment or from the various organs of the body

• transmit impulses to the nerve centers in the brain & spinal cord

• composed of 2 Types of Cells: Neurons & Neurologia

NeuronNeuronNeuronNeuron

• consist of nerve cell body → somasomasomasoma or perikperikperikperikaryonaryonaryonaryon; 2 processes (nerve fibers): 1 axon & 1 dendrite 1.1.1.1. axonaxonaxonaxon

� thinner & longer compared to the dendrite, branches extensively � gradually decreases in diameter as it furthers the cell body � conveys impulses away from the cell body

2.2.2.2. dendritedendritedendritedendrite � short & confined near the cell body � may be more than one process in a neuron � have thorny appearance � conveys impulses towards the cell body


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• Types of Neurons (based on Processes) a. Multipolar NeuronMultipolar NeuronMultipolar NeuronMultipolar Neuron – 1 axon & several dendrites b. Bipolar Neuron Bipolar Neuron Bipolar Neuron Bipolar Neuron – 1 axon & 1 dendrite; least numerous c. Unipolar NeuronUnipolar NeuronUnipolar NeuronUnipolar Neuron – 1 process that separate into an axon & a dendrite

Teased Nerve:

� Myelin SheathMyelin SheathMyelin SheathMyelin Sheath – appears as a tube surrounding the axis cylinder

(cytoplasm of the axon); produced by Schwann cellsSchwann cellsSchwann cellsSchwann cells � Nodes of RanvierNodes of RanvierNodes of RanvierNodes of Ranvier – regions in the myelin sheath that appears

interrupted

NeurologiaNeurologiaNeurologiaNeurologia

• supporting cells of the neurons • possess several branching processes Cross Section of Nerve:Cross Section of Nerve:Cross Section of Nerve:Cross Section of Nerve: � FascicleFascicleFascicleFascicle → single discrete bundle of nerve fibers & connective tissue

� EpineuriumEpineuriumEpineuriumEpineurium → connective tissue that binds several fascicles in nerve trunks

� PerineuriumPerineuriumPerineuriumPerineurium → dense connective tissue covering each fascicle

� EndoneuriumEndoneuriumEndoneuriumEndoneurium → covers individual nerve fibers

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Exercise 7 animal tissues