CH. 10 - Muscles and Locomotion

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Introduction

1. Muscles and Locomotion

1. The musculoskeletal forms the basic internal framework for vertebrates body

2. Muscle and bone work together to produce voluntary movement

3. Muscle and bone independently do a lot too

4. Unicellular organisms rely on specialized organelles for locomotion and invertebrates have numerous ways of getting about

5. Functions of muscles and skeleton in vertebrate is support and locomotion

Keywords

1. Unicellular Locomotion

1. Cilia - hair on the cell surface that moves the cells

2. Flagella - long tail that moves protozoans or algae

3. Pseudopodia - extending cell membrane for movement

2. Invertebrate Locomotion

1. Chitin - hard exoskeleton that offers some protection in arthropods

2. Molting - Required for growth in arthropods with chitin exoskeleeton

3. Planaria - two layers of muscle, longitudinal and circular

4. Setae - bristles in lower part of segment that anchors the earthworm as it moves

3. Vertebrate Skeleton

1. Appendicular skeleton - bones of appendages, and the pectoral and pelvic girdles.

2. Axial skeleton - framework of body, show point of attachment, appendicular skeleton

3. Bone - mineralized connective tissue for withstanding stress and support

4. Cartilage - connective tissue that's soft and flexible

5. Compact bone - dense bone that does not have any cavities when seen by naked eye

6. Endochondral ossification - cartilage replaced by bone

7. Endoskeleton - framework of vertebrate organism

8. Extension - straightening of a joint

9. Flexion - bending of a joint

10. Haversian Canal - microscopic channel inside osteons, surrounded by lamellae

11. Insertion - point of attachment of muscle to bone that moves

12. Intramembranous ossification - mesenchymal (undifferentiated) connective tissue is transformed into bone

13. Lamellae - concentric circles of bony matrix surrounding haversian canal

14. Ligaments - bone to bone connector

15. Origin - point of attachment of a muscle to a stationary bone

16. Osteoblasts - synthesize and secrete organic makings of bone matrix

17. Osteoclasts - mass of cells that does bone resorption

18. Osteocytes - two types, osteoblasts and osteoclasts, found in bone tissues

19. Osteons - structural units of bony matrix in compact bone

20. Spicules - interconnecting lattice inside spongy bone

21. Spongy Bones - Loose structure with bone marrow (produces blood)

22. Sutures - immovable joints holding the bone of skull together

4. Muscular System

1. A band - spans entire length of thick filament, even including thin filament

2. Absolute refractory period - right after contraction, muscle fiber unresponsive

3. Actin - makes up the thin filaments in sarcomere

4. Arginine phosphate - high energy compound temporarily stored in muscle of invertebrates

5. Calcium Ion - released by sarcoplasmic reticulum to initiate contraction

6. Cardiac Muscle - composed of skeletal and smooth muscle and have only 1 or 2 nuclei.  Myogenic.

7. Contractile fibers - make up the muscle tissue

8. Creatine Phosphate - temporary storage unit for vertebrates in muscle and some invertebrate

9. H zone - region containing only thick filament

10. I Band - region containing only thin filament

11. M line - center of the sarcomere

12. Myofibrils - filaments in muscle fiber, divided up into sarcomere.  Contains a lot of mitochondria

13. Myogenic - contracting without stimulation from nerve cells

14. Myoglobin - hemoglobin like that supply oxygen to muscles.

15. Myosin - make up the thick filaments in sarcomere

16. Neuromuscular junction - synpatic cleft between nerve terminal and sarcolemma

17. Sarcolemma - cell membrane of muscle fiber, propagates action potential

18. Sarcomeres - contractile units in myofibrils

19. Sarcoplasm - cytoplasm of muscle fiber

20. Sarcoplasmic reticulum - envelops the myofibrils and stores calcium ions

21. Skeletal muscle - voluntary and innervated by somatic nervous system with multinucleated cell.  Contain myofibrils and is striated.

22. Smooth muscle - one centrally located nucleus, innervated by autonomic nervous system.  Are myogenic

23. Summation -contractions continuous and so frequenet that muscle cannot relax

24. Tetanus - prolonged contraction, muscle will fatigue and contraction weaken

25. Tonus - state of partial contraction

26. Z lines - boundary of the sarcomere, anchors the thin filaments

Unicellular Locomotion

1. Structure

1. Cilia

1. Contains a cylindrical stalk of eleven microtubules

2. Nine paired microtubules arranged in circle with two single microtubules in the center

3. Moves by beating all the cilia in an unison

2. Flagella

1. Contains a cylindrical stalk of eleven microtubules

2. Nine paired microtubules arranged in circle with two single microtubules in the center

3. Moves by power stroke

3. Pseudopodia

1. Amoeboid movement where cell membrane extends forward and rest of the body follows

Invertebrate Locomotion

1. Hydrostatic Skeletons

1. Flatworms

1. Arranged in two antagonistic layers

1. Longitudinal

1. Contraction here shortens the animal

2. Circular

1. Contraction here causes the incompressible fluid to flow longitudinally

2. The muscles contract against the resistance of the incompressible fluid within the tissue

1. The fluid is the hydrostatic skeleton

3. The same type of locomotion persists in annelids

4. Planaria is the best example, flat worm

2. Segmented Worms (Annelids)

1. Earthworms advance by muscles on the hydrostatic skeleton

2. Bristle called setae, anchors the earthworm temporarily which muscles inches it ahead

2. Exoskeleton

1. Hard skeleton that covers all muscles and organs of some invertebrates

2. Found principally in arthropods

1. Composed usually of chitin

1. Noncellular material secreted by the epidermis

2. Imposes limitation on growth

1. Thus periodic molting is required for body growth

3. Offers protection

Vertebrate Skeleton

1. General

1. Endoskeleton

1. Framework of the organism

2. Provides protection by surrounding delicate organs in bone

1. Rib protects heart and lungs

2. Skull protects brain

3. Vertebral column protects spinal cord

2. Muscles attached to bone, permitting movement

3. Two major components are bone and cartilage

2. Structure of the Skeleton

1. Cartilage

1. Type of connective tissue

1. Softer and more flexible than bone

2. Retained in adults where firmness and flexibility required

3. Examples

1. External ear, nose, walls of larynx and trachea

2. Skeletal joints

2. Bone

1. Mineralized connective tissue

1. Ability to withstand physical stress

2. Ideally designed for body support

1. Tissue is hard and strong

2. Somewhat elastic and lightweight

3. Two types, compact bone and spongy bone

4. Compact Bone

1. Dense bone without any cavities when observed by naked eye

2. Bony matrix deposited in structural units called osteons

3. Osteons consists of a central microscopic channel called Haversian canal

4. Haversian canal is surronded by concentric circles of bony matrix called lamellae

5. Spongy Bone

1. Less dense and consists of interconnecting lattice of bony spicules

2. Cavities in between spicules are filled with yellow or red bone marrow

3. Yellow marrow - inactive and infiltrated by adipose tissue

4. Red Marrow - blood cell formation

3. Osteocytes

1. Osteoblasts

1. Synthesize and secrete organic constituents of bone matrix

2. Osteoclasts

1. Large cells that reabsorbs bone

4. Bone Formation

1. Endochondral ossification

1. Existing cartilage is replaced by bone

1. Usually how long bones came about

2. Intramembranous ossification

1. Mesenchymal (embryonic and undifferentiated) connective tissue is transformed into bone

3. Organization of Vertebrate Skeleton

1. Axial Skeleton

1. Basic framework of the body

1. Skull, vetebral column, rib cage

2. Point of attachment of appendicular skeleton

2. Appendicular Skeleton

1. Bones of appendages, pectoral, and pelvic girdles

3. Holding bones together

1. Sutures

1. Immovable joints holding bones of skull together

2. Movable Joints

1. Bones that move relative to one another

2. Supported and strengthened by ligaments

3. Ligaments

1. Serve as bone to bone connections

4. Tendons

1. Attach skeletal muscle to bones and bend the skeleton at moveable joints

4. Point of attachment

1. muscle to stationary bone is called the "origin"

2. Muscle to bone that moves is called the "insertion"

3. Straightening a joint is called "extension"

4. Flexion refers to bending of a joint.

Muscular System

1. General

1. Muscles consist of bundles of specialized contractile fibers held together by tissues

2. Three types: skeletal muscle, smooth muscle, and cardiac muscle

2. Skeletal Muscle

1. Structure

1. Innervated by somatic nervous system

2. Fiber cells

1. are multinucleated

2. created by fusion of several mononucleated embryonic cell

3. Embedded in fibers are filaments called myofibrils

4. Cytoplasm is called sarcoplasm

5. Cell membrane is called sarcolemma

1. Capable of propagating action potential

2. Connected to system of transverse tubules oriented perpendicularly to the myofibrils

1. Provides channel for ion flow throughout the muscle fiber

2. Able to propagate an action potential

3. Myofibrils

1. Further divided into contractile units called sarcomeres

2. Enveloped by modified endoplasmic reticulum that stores calcium

3. Also called sarcoplasmic reticulum

4. Mitochondria are very abundant in muscle cells, distributed throughout myofibrils

4. Has striations of light and dark bands

1. Also referred to as striated muscle

2. Function

1. Responsible for voluntary movement

3. Sacromere

1. Structure

1. Composed of thick and thin filaments

1. Thin filaments are chains of actin molecules

2. Thick filaments are organized bundles of myosin molecules

2. Organized as following

1. Z line

1. Define the boundaries of single sarcomere

2. anchor the thin filament

2. M line

1. Runs down the center of the sarcomere

3. I band

1. Region containing thin filaments only

4. H Zone

1. Region containing thick filaments only

5. A band

1. Spans the entire length of thick filaments and overlapping portions of the thin filament

2. Contraction

1. Stimulated by message from somatic nervous system sent via motor neuron

2. Link between nerve terminal and sarcolemma of the muscle fiber is called neuromuscular junction

1. Space between the two part is called "synapse"

2. Release of neurotransmitter happen when motor neuron depolarize

3. If enough neurotransmitter binds to the sarcolemma's receptor site, action potential is generated

3. The action potential is passed along the sarcolemma and the T system into the interior of muscle fiber.

1. This causes sarcoplasmic reticuluculm to release calcium ions into the sarcoplasm.

2. The calcium ion initiate the contraction of the sarcomere.

1. Actin and myosin slides past each other as the contraction occur

3. Stimulus and Muscle Response

1. Individual muscle fibers exhibit all-or-none response

1. Only with enough calcium ion, above the threshold can elicit contraction

2. Strength of contraction cannot be increased

2. Strength of the entire muscle can be increased by adding more muscle fibers

3. Simple Twitch

1. Response of a single muscle fiber to brief stimulus above threshold

2. Latent Period

1. Time between stimulation and onset of a contraction

2. Action potential spread along the sarcolemma and calcium ion released

3. Contraction period

1. When the H-Zone and I-band disappears and only A-band exist

4. Relaxation period

1. Muscle is unresponsive to stimulus

2. Absolute refractory period is another name for this

4. Summation and Tetaus

1. Temporal Summation

1. When fibers of muscles are constantly stimulated, it cannot fully relax

2. Contractions combine and becomes stronger and prolonged

2. Tetanus

1. When contractions become continuous that the muscle cannot relax

2. If maintained, muscle will fatigue and contractions will weaken

5. Tonus

1. State of partial contraction

1. Never fully completely relaxed

4. Smooth Muscle

1. Responsible for involuntary actions

2. Innervate by autonomic nervous system

3. Found in digestive tract, bladder, uterus, blood vessel walls, etc

4. Posses one centrally located nucleus

5. Lack striation of skeletal muscle

6. Myogenic - capable of contracting without stimulation from nerve cells

5. Cardiac Muscle

1. Tissue of the heart

2. Possess characteristics of both skeletal and smooth muscle

3. Actin and myosin are arranged in sarcomeres, giving the striated appearance

4. Only have one or two centrally located nuclei

5. Myogenic - capable of contracting without stimulation from nerve cells

Energy Reserves

1. General

1. ATP is primary source of energy

2. Very little ATP stored in muscle

3. Other form of energy must be stored and rapidly converted to ATP

2. Creatine Phosphate and Arginine Phosphate

1. Creatine phosphate - energy temporarily stored in high energy compound

1. Found in vertebrates and some invertebrates

2. Arginine phosphate

1. Similar compound found in invertebrate

3. Myoglobin

1. Hemoglobin like protein found in muscle tissue

Has high oxygen affinity and maintains oxygen supply in muscles by binding to oxygen tightly until needeeed