General Histology and Histotechnique (1st semester 2012-2013)MUSCLE TISSUES                                              S...
General Histology and Histotechnique (1st semester 2012-2013)-      Striations are present                                ...
General Histology and Histotechnique (1st semester 2012-2013)    Individual muscle fibersTissue sheaths – extend to from ...
General Histology and Histotechnique (1st semester 2012-2013)                                                            -...
General Histology and Histotechnique (1st semester 2012-2013)2.   I-band – isotropic-    Lighter dense area-    Where thin...
General Histology and Histotechnique (1st semester 2012-2013)Histological parts:                                         -...
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GHH Muscle Tissues


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General Histology and Histotechnique 2012 - 2013
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GHH Muscle Tissues

  1. 1. General Histology and Histotechnique (1st semester 2012-2013)MUSCLE TISSUES Similarities of Muscle Tissues - Cells of muscles: fibersMyology Muscle contractionFunctions of muscle movements: - Depends on two types of myofilaments (contractile proteins)1. Produce body movements  ActinEx. Skeletal muscle – Pull bones- Muscle movements; walking, running  Myosin- With the help of joints - Sarcolemma – plasma membrane2. Stabilize body positions - Sarcoplasm- To sit, stand, balance position3. Regulate organ volume- Due to smooth muscleSmooth muscleLocation:Stomach – for temporary storageUterine – Store temporarily the urine4. Move substances within the bodyEx.Cardiac muscle - blood will be pumpedSmooth muscle – enzymes, food GITSkeletal muscle – substances within the body; producesLactic acid.5. Produce heat- Body movement – Increases temperaturePropertiesContractility- To generate the pulling force- Ability of muscle to contract forcefullyExcitability- Ability to respond to a certain stimuli to produce electrical signals SKELETAL MUSCLEExtensibility - To move the bones of skeleton- Ability to stretch without being destroyed - It does not consists of single muscle fiber - It form multinucleated used muscle fiberElasticity - Form by diffusion of myoblast- Able to go back to its original shape/length  Embryonic cells of skeletal muscle
  2. 2. General Histology and Histotechnique (1st semester 2012-2013)- Striations are present  Dense irregular connective- Nucleus is found at the Peripheral – at the sides tissue- Attached to the bones c. EndomysiumI. Connective Tissue components of skeletal muscle - 1 bundle of muscle - Covers the individual muscle fiber1. Fascia – (Bandage) - Areolar tissue- Fibrous connective tissue that is deep to the skin - Separate muscle fibers from each others- Surrounds muscles and other organs of the body. 2 types:a. Superficial fascia or the subcutaneous layer- separate muscles from skinMade up of:- Areolar connective tissue- Adipose tissueFunctions: 1. It provides a pathway for nerves and Blood vessels to enter and exits muscles. 2. Stores most of the triglycerides 3. Serves as good insulating layer; reducing heat loss – due to Connective tissue 4. Protects muscles from physical traumab. Deep fascia- A dense irregular connective tissueFunctions:- Lines the body wall and limbs- Holds muscles together- Allows free movement of muscles- Carries Blood vessels, nerves, Lymphatic vessels- Fills the spaces between muscles2. Three layers of connective tissue- Extend from the deep fascia to further protect and strengthen skeletal muscle a. Epimysium- Encircles the whole muscle/covers the muscle Basic features of skeletal muscle- Dense irregular connective tissue Nerves and blood vessels b. Perimysium - Each skeletal muscle is supplied by branches of one- Encircles bundles of muscles nerve, one artery, one or more veins  Wrapped by Fascicle - Nerves and vessels branch repeatedly  10-100 or more muscle; - Smallest nerve branches serve Individual muscle fibers
  3. 3. General Histology and Histotechnique (1st semester 2012-2013)  Individual muscle fibersTissue sheaths – extend to from the tendon - attachesmuscles to bone.  Neuromuscular junction- A place in the body where nerves meet a muscle.- A synapse the motor neuron and the muscle fiber.Muscle attachments- Most skeletal muscles run from one bone to another b. The sarcolemma of the fiber encloses sarcoplasm- One bone will move – other bone remains fixed and myofibrils which are striated  Origin – less movable part of the bone  Insertion – more movable attachment c. A sac of sarcoplasm is reticulum wraps around each myofibril - Composed of a triad: is a two terminal cisterns and a T (transverse tubule). Histological featuresMicroscopic organization and developmenta. Embryonic development- Fusion of myoblasts into muscle fibersMyoblast – fused to form the muscle fibers- After fusion, still with satellite cell, immature muscle fiber will lose their potential to divide hence, satellite cell retains it.- It cannot have any cell divisionSatellite cell – forms the muscleFunctions:- Acts as a reserved population of cells- Whenever skeletal muscle is in its normal state it is inactive or quiescent; if it is injured it becomes active.- It continues to divide in order to repair and grow more muscle fibers.- Repair and maintenance of skeletal muscle
  4. 4. General Histology and Histotechnique (1st semester 2012-2013) - The cytoplasm of muscle fibers - Contains a substantial amount of glycogen and myoglobin  Oxygen binding protein which is red colored globins and found only in muscle fibers. 3. Myofibrils - Contractile element of muscles - Contains overlapping thick and thin filaments - With prominent striations Alternating line and dark bands 4. Sarcoplasmic Reticulum - Fluid-filled system of membranous sacs thatStructure of a skeletal muscle fiber encircles each myofibrils Function: - Releases Calcium ions to trigger muscle contraction 5. Sarcomere - Basic functional unit of myofibril - Compartment of filaments inside the myofibrils 6. Filaments - Within the myofibrils of two types: a. Thin filaments - 8 nm in diameter - Protein: Myosin b. Thick filamentsSarcoplasmic reticulo  Triad - 16 nm in diameter - Protein: Actin1. Sarcolemma- Muscle fibers plasma membrane which is 7. Mitochondria perforated with thousands of tiny invagination - Small and less numerous skeletal muscle fiber called triad. - For cell respirationTwo terminal sisters: - Powerhouse of the cella. Terminal cisterns - For the synthesis of ATP- Structure madeup of two strands on either strands of T tubule. Zones and bands of sarcomere:b. T tubules- These are tunnels from the surface towards the 1. A-band – anisotropic center of each muscle fiber. - Darker middle portionFunction of Triad: - Where thick filaments (myosin) are locatedTo ensure that all parts of the muscle fiber become - Toward the end of the A band is a zone of overlap:excited by an action potential virtually simultaneously. where thick and thin filaments lie side by side2. Sarcoplasm
  5. 5. General Histology and Histotechnique (1st semester 2012-2013)2. I-band – isotropic- Lighter dense area- Where thin filaments (actin) extend- No thick filaments3. Z-line- Distinct dark line running down the middle of the I- band- Where thin filaments are attached end to end- Zone of apposition (increase in diameter) of actin filaments belonging to two neighboring sarcomeres4. M-line- So named because it is at the middle of sarcomere- Where thick filaments are attached end-to-end in the center of the A-band- Band of connections between myosin filaments- Supporting proteins that hold thick filaments together at the center of H-zone.5. H-band- Appears along the middle of A-band, between the free ends of the thin filaments when muscles are stretched.- Zone of myosin filaments only (no overlap with actin filaments) within the A-band CARDIAC MUSCLE II. Cardiac muscle tissue - Principal muscular tissue in the heart wall - Shorter in length and larger in diameter - Exhibit branching which gives an individual fiber and y-shaped appearance - Nucleus centrally located
  6. 6. General Histology and Histotechnique (1st semester 2012-2013)Histological parts: - Found in wrap around sheets that form part of the1. Sarcolemma walls of smaller arteries and veins and hollow- Plasma membrane surrounding the cardiac muscle viscera such as the stomach, intestines, uterus, and urinary bladder.2. Sarcoplasm- The cytoplasm 2. Multiunit smooth muscle tissue - Consists of individual fibers, each with its own3. Mitochondria motor neuron terminals and with few gap junctions- Larger and more numerous between neighboring fibers - Found in the walls of large arteries, in airways to4. T-tubules the lungs, in arrector pili muscle that attaches to- Wider and less abundant and there is only one T- hair follicles and muscles of iris that adjust pupil tubule per sarcomere located at the Z-disc. diameter5. Sarcoplasmic reticulum Histological features:- Few, has limited intracellular reserved of Calcium ions. 1. Endomysium - Surrounds the smooth muscle fiber6. Myofibril- Contractile unit 2. Have a single centrally located oval nucleus7. Sarcomeres 3. Sarcoplasm- Functional unit, same zones, bands and lines as the - Contains both thick and thin filaments skeletal muscle. 4. There is no sarcomereSMOOTH MUSCLE 5. Contains intermediate filaments 6. Have a sarcoplasmic reticulum which is scanty 7. Do not have T-tubules 8. Gap junction in visceral smooth muscles is present but not in multiunit smooth muscle.III. Smooth muscle tissueTwo types:1. Visceral smooth muscle tissue- Also known as the single unit smooth muscle tissue