HSC 230: Lecture Exam #3

Muscle 3: Breakdown/Review (Part 1)

(Part 1) Anaerobic: - Glycogen --> Glucose --> (with oxygen) ATP - (No oxygen) Pyruvic acid --> Lactic Acid Creatine Phosphate: - Creatine phosphate uses ADP to make ATP Aerobic: - Glucose --> Pyruvic acid --> Mitochondria --> makes carbon dioxide + water + ATP

Muscle 1: Muscle Attachment (Part 1)

(Part 1) Endomysium, Perimysium & epimysium may extend together past the muscle fibers to form a tendon - Tendon: a cord of dense regular connective tissue w/parallel bundles of collagen fibers that attach muscle to the periosteum of bone Endomysium, Perimysium & epimysium may extend together past the muscle fibers to form a broad flat sheet called an aponeurosis - Aponeurosis: can attach muscle to bone but usually are associated with attaching functional muscle groups - EX: External Obliques & Epicranius Notes: - Tendons are extensive connective tissue. - You get tears in tendons before separations. - External obliques attach to one another functionally. *Superficial on the lateral sides of the abdomen. - Muscle fibers contract (get smaller) which moves something. - Cranius = Skull

Muscle 2: Forearm View

- Cubital fossa - Cephalic vein - Median cubital vein - Brachioradialis - Styloid process of radius - Thenar eminence - Palmar surface of hand - Pollex (thumb) - Flexion lines - Volar surface of fingers - Flexion lines - Hypothenar eminence - Styloid process of ulna - Flexor carpi ulnaris - Palmaris longus - Flexor carpi radialis - Biceps brachii - Medial epicondyle - Triceps brachii - Olecranon - Head of radius - Brachioradialis - Flexor carpi ulnaris - Exensor carpi ulnaris - Extensor digitorum - Tendons of extensor digitorum - Dorsum of hand

Muscle 1: Lateral Compartment of the Leg

- Fibularis Longus - Fibularis Brevis 2 muscles in this compartment Both plantar flex and evert the foot Provides lift and forward thrust

Muscle 2: Male Back & Gluteal Region

- Flexor carpi ulnaris - Brachioradialis - Biceps brachii - Triceps brachii - Deltoid - Deltoid: Anterior part - Deltoid: Middle part - Deltoid: Posterior part - Teres major - Infrapsinatus - Medial border of scapula - Trapezius - Vertebral furrow - Erector spinae - Latissimus dorsi - Iliac crest

Muscle 1: Muscles in Facial Expression (Frontal View)

- Frontalis - Orbicularis Oculi - Levator Labii Superioris - Zygomaticus Minor - Zygomaticus Major - Risorius - Modiolus - Depressor Anguli Oris - Depressor Labii Inferioris - Platysma - Galea Aponeurotica - Corrugator Supercilii - Nasalis - Levator Anguli Oris - Masseter - Buccinator - Orbicularis Oris - Mentalis (Cut) Notes: - Orbicularis = Circular - Levator Labii Superloris —-> Elevated Lip of the Superficial layer - Mentalis muscle —> Muscle of the chin

Muscle 1: Muscles in Facial Expression (Lateral)

- Galea Aponeurotica - Temporalis - Occipitalis - Zygomatic Arch - Masseter - Sternocleidomastoid - Levator Scapulae - Inferior Pharyngeal Constrictor - Thyrohyoid - Sternothyroid - Omohyoid - Frontalis (Cut) - Corrugator Supercilii - Orbicularis Oculi - Nasalis - Levator Labii Superioris - Zygomaticus Minor - Zygomaticus Major - Orbicularis Oris - Modiolus - Risorius (Cut) - Mentalis - Depressor Labii Inferioris - Depressor Anguli Oris - Buccinator

Muscle 1: Posterior Compartment of Leg Superficial Group of Plantar Flexors

- Gastrocnemius - Plantaris - Soleus Gastrocnemius = Flexes knee and plantar flexes ankle Soleus = plantar flexes ankle

Muscle 1: Posterior Muscles Acting on Hip

- Gluteus medius - Gluteus maximus - Iliotibial band Gluteus maximus - Forms mass of the buttock - Prime hip extensor - Provides most of lift when you climb stairs Iliotibial band - Band of fascia lata attached to the tibia.

Muscle 2: Leg and Foot, Posterior View

- Hamstring muscles - Biceps femoris tendon - Semitendinosus tendon - Popliteal fossa - Gastrocnemius - Medial head gastrocnemius - Lateral head gastrocnemius - Soleus - Fibularis longus - Tibialis anterior - Calcaneal tendon - Lateral malleolus - Extensor digitorum brevis - Calcaneus

Muscle 1: Anterior Thigh Cadaver Muscles

- Iliac Crest - Iliopsoas (iliacus & Psoas major) - Anterior superior iliac spine - Tensor fasciae latae - Iliotibial band - Adductor magnus - Pectineus - Adductor brevis - Adductor longus - Gracilis - Sartorius - Vastus intermedius - Rectus femoris - Vastus lateralis - Vastus medialis - Quadriceps femoris tendon - Patella - Patellar ligament Notes: - 3 vastus muscles - On the femur (knee extensions)

Muscle 2: Female Back & Gluteal Region

- Infraspinatus - Trapezius - Olecranon - Iliac crest - Gluteus medius - Gluteus maximus - Hamstring muscles - Acromion - Medial border of scapula - Inferior angle of scapula - Latissimus dorsi - Erector spinae - Sacrum - Coccyx - Natal cleft - Greater trochanter of femur - Gluteal fold

Muscle 2: Upper Limb, Lateral View

- Interphalangeal joints - Metacarpophalangeal joints - Styloid process of radius - Extensor digitorum - Trapezius - Acromion - Deltoid - Pectoralis major - Biceps brachii - Triceps brachii - Triceps brachii lateral head - Triceps brachii long head - Brachioradialis - Extensor carpi radialis longus - Lateral epicondyle of humerus - Olecranon

Muscle 2: Axillary Region

- Olecranon - Biceps brachii - Triceps brachii - Anterior axillary fold (pectoralis major) - Posterior axillary fold (latissimus dorsi) - Deltoid - Axilla (armpit) - Pectoralis major - Latissimus dorsi - Serratus anterior - Rectus abdominis - External abdominal oblique

Muscle 1: Adductors of the Hip Joint

- Pectineus - Adductor brevis - Adductor longus - Adductor magnus 5 muscles act as adductors Adductor magnus is hip joint extensor Gracilis is flexor of knee Pectineus, Adductor brevis and Adductor longus adduct femur

Muscle 2: Leg and Foot, Medial Foot

- Semimembranosus - Semimembranous tendon - Vastus medialis - Patella - Semitendinosus tendon - Medial epicondyle of femur - Medial condyle of tibia - Medial head of gastrocnemius - Tibia - Soleus - Medial malleolus - Extensor hallucis longus tendon - Medial longitudinal arch - Abductor hallucis - Head of metatarsal I

Muscle 2: Female Thorax & Abdomen

- Supraclavicular fossa - Clavicle - Acromion - Deltoid m. - Breast - Axillary tail - Nipple - Areola - Corpus (body) - Costal margin - Linea semilunaris - External abdominal oblique m. - Trapezius m. - Suprasternal notch - Manubrium - Angle - Body (gladiolus) - Xiphoid process - Linea alba - Rectus abdominis m. - Umbilicus - Anterior superior spine of ilium

Muscle 2: Male Thorax and Abdomen

- Supraclavicular fossa - Clavicle - Deltoid - Pectoralis major - Nipple - Rectus abdominis - Tendinous insertion of rectus abdominis - Anterior superior spine of ilium - Iliac crest - Inguinal ligament - Sternocleidomastoid - Thyroid cartilage - Trapezius - Suprasternal notch - Acromion - Manubrium - Body - Xiphoid process - Serratus anteiror - Linea semilunaris - Linea alba - Umbilicus - External abdominal oblique

Muscle 1: Superficial Muscles of Back

- Trapezius - Latissimus Dorsi - Semispinalis - Splenius Capitis - Levator scapulae - Rhomboideus - Supraspinatus - Infraspinatus - Teres major - Gluteus maximus - Gluteus medius

Muscle 3: Excitation-Contraction Coupling - Simpler Breakdown

1. Arrival of nerve signal 2. Acetycholine (Ach) release 3. Binding of ACh to receptor 4. Opening of ligand-gated ion channel; creation of end-plate potential 5. Opening of voltage-gated ion channels; creation of action potentials 6. Action potentials propagated down T tubules 7. Calcium released from terminal cisternae 8. Binding of calcium to troponin 9. Shifting of tropomyosin: exposure of active sites on actin 10. Hydrolysis of ATP to ADP + P1: activation and cocking of myosin head 11. Formation of myosin-actin cross bridge 12. Power stoke; sliding of thin filament over thick filament 13. Binding of new ATP; breaking of cross-bridge 14. Cessation of nervous stimulations and ACh release 15. ACh breakdown by acetycholinesterase (AChE) 16. Reabsorption of calcium ions by sarcoplasmic reticulum 17. Loss of calcium ions from troponin 18. Return of tropomyosin to position blocking active sites of actin

Muscle 3: Overview of Skeletal Muscle

1. Attach/cover bones 2. Longest fibers—cells up to 12 inches long 3. Multinucleated—100's of nuclei in each fiber - Every mature muscle cell developed from 100's myoblasts that fuse together in the fetus. (multinucleated) 4. 4. Striations - Alternating Thick & Thin Filaments 5. Voluntary 6. Contract rapidly 7. Tires easily—need rest after short period of activity (Quickly uses up ATP resources) - Slow vs Fast Twitch 8. Adaptable—pick up a pin, pick up a book - Mature muscle cells cannot divide - Muscle growth is a result of cellular enlargement by hormones & not cell division (hGH and testosterone) *Hypertrophy - increase in cell size - Satellite cells (myoblasts that stay in skeletal muscle) retain the ability to regenerate new cells. *Repair & Hyperplasia (Jury is still out- IGF-1, hGH) 9. Wind up toy—runs down Notes: - Skeletal muscle has connective tissue - Multinucleated (start as myoblasts) *Myoblasts = muscle fibers - Striations = alternations of thick and thin muscle filaments that are lined up. - Z discs migrate toward the Titin filaments - Cardiac muscles only stop when we can't/don't live. - The consistent practicing or doing of a muscle, the muscles will grow because of it to accommodate it. - Hormones are responsible for the muscle growth. - Skeletal muscles have satelite cells that regenerate cells. In Class Notes: 3. Multinucleated - Myoblasts build muscle cells. - Satellite cells are myoblasts that remain themselves. *They form around other muscle cells. - When you tear muscles (feeling sore after), satellite cells fill in the torn regions, repairing. *Satellite cells fuse with the myoblasts, then healing the muscle. 4.Striations - Alternation of Thick and Thin Filament *Actin = Thin Filament *Myosin = Thick Filament *Not directly attached to the z disc. - 1 muscle cell is shaped like a cylinder. - The contractile unit of a muscle cell is a sarcomere. *Contraction is the shortening of a muscle fiber. - Each cell has hundreds of sarcomeres. *Each shortens. - Heads of the myosin have the job of extending out to connect to other actin, pulling them in. *Actin slides past. 5.Voluntary - Cardiac muscle doesn't tire. 8.Adaptable - Skeletal muscle is adaptable; it grows. 9.Wind up toy - runs down - Grow in cellular size ---> hypertrophy *How most adults grow. - Grow in cellular number ---> hyperplasia *How babies grow into adults

Muscle 3: Unique Properties of Muscle

1. Excitability - Receive and respond to stimulus - Stimulus can be chemical *Neurotransmitter *Hormone *pH change - Respond *Make and transmit electrical current (A.P.) along sarcolemma to contract—cause movements 2. Contract - Shorten when stimulated, different from all other tissue types 3. Extensibility - Stretched and extended 3X (shorten when contract), stretch when relaxed 4. Elastic - Resume to resting length after stretched, recoil—return to the original length 5. Conductivity - More than local effect, wave of excitation Notes: - Exercising outside can lead to cramping due to environment and action. - Muscles can stretch during relaxation. In Class Notes: 1.Excitability - Receive and respond to stimulus *Stimulus can be chemical (neurotransmitter, hormone, pH change) - Respond *Make and transmit electrical current along sarcolemma to contract (cause movement) 3.Extensibility - They are extensible - can be stretched, but they like to return to their regular size.

Muscle 3: Overview of Smooth Muscle

1. Walls of hollow organs - Stomach, bladder, bronchioles 2. No striations - Still have Thick & Thin Filaments 3. Involuntary - ANS & Pacemaker Cells 4. Slow contractions 5. Last long time 6. Steady engine going along tirelessly In Class Notes: 2.No Striations - Different arrangement of myosin and actin cause the lack of striations

Muscle 3: Heat Production

20-25% of energy released during muscle contraction is work The rest is given off as heat for homeostasis Basal Metabolic Rate (BMR) Exercise—hot, liberated with heat from ATP use, sweat - 42% of ATP for work - 58% for heat 85% of heat for thermoregulation comes from skeletal muscle contractions

Muscle 3: Muscle Types

3 types: - smooth - cardiac - skeletal Differ by: - Structure of cells - Body location - Function - How activated to contract Similar by: - Elongated muscle cells called muscle fibers - Contraction dependent on 2 types of myofilaments (actin and myosin) - Prefix "myo", "mys" "sarco" = muscle - Sacrolemma = plasma membrane of muscle fiber - Sarcoplasm = muscle fiber cytoplasm Notes: - Striated = cardiac and skeletal - Nonstriated = smooth - Cardiac —-> involuntary - Muscle cells = Muscle fibers In Class Notes: - Striations are caused by the alternation of thick and thin filaments. - Skeletal Muscle: Voluntary, Striated - Reflexes can be overridden. *Ex: when you're at the doctors and they tap your knee, but you override the reflex so it doesn't happen. - Striations *Myo, Mys, Sarco = Muscle *Sacrolemma is the plasma membrane of the muscle fiber. *Sarcoplasm is the cytoplasm of the plasma membrane.

Muscle 1: Muscles of Mastication

4 Major muscles - Temporalis - Masseter - Lateral Pterygoid - Media Pterygoid Arise from skull and insert on mandible Temporalis and Masseter elevate the mandible Medial and Lateral Pterygoids help elevate, but produce lateral swinging of jaw

Muscle 1: Muscles of the Abdomen

4 Pairs of sheetlike muscles - External oblique - Internal oblique - Transverse abdominis - Rectus abdominis Functions - Support the viscera - Stabilize the vertebral column - Help in respiration, urination, defecation and childbirth

Muscle 1: Organization of Muscles

600 Human skeletal muscles General structural and functional topics - Muscle shape and function - Connective tissues of muscle - Coordinated actions of muscle groups - Muscle innervation

Muscle 3: Motor Units

A motor neuron and the muscle fibers it innervates - Dispersed throughout the muscle - When contract together causes weak contraction over wide area - Provides ability to sustain long-term contraction as motor units take turns resting (postural control) Fine control - Small motor units contain as few as 20 muscle fibers per nerve fiber - Eye muscles Strength control - Gastrocnemius muscle has 1000 fibers per nerve fiber Notes: - Motor units help with fatigue; when one fiber gets tired, another takes over.

Muscle 3: Muscle Metabolism

ATP used in muscle contraction - Na/K pump - Bind actin/myosin - Calcium flow back into SR - ACH re-uptake back into the axon terminal - Glucose production for future ATP use Not stored very much (only 4-6 sec. worth) - Reserves exhausted fast *Each myosin head exhibits 5 power strokes/second, each requires 1 ATP, so ATP is used quickly ATP only energy source that can be used directly in contraction ATP regenerated 3 ways: - ADP + creatine phosphate - Anaerobic pathway—glycolysis - Aerobic respiration

Muscle 1: Muscles of Respiration

Breathing requires the use of muscles - Diaphragm and external intercostal muscles - Internal intercostal muscles Contraction of first 2 produces inspiration Contraction of last produces forced expiration Normal expiration requires little muscular activity - Elastic recoil and gravity collapses the chest - Inspiratory muscles active in braking action, so exhalation is smooth Notes: - The diaphragm either expands or flattens as a result of breathing in and out.

Muscle 1: Deep Fascia

Coarser dense irregular connective tissue Holds muscles with similar function together Separates adjacent muscles Fills spaces between muscle Notes: - Coarse

Muscle 1: Skeletal Muscle

Contains: - Connective Tissue - Nervous Tissue - Blood Vessels Notes: - All skeletal muscle have neurons that stimulate contractions - A muscle cell is a muscle fiber

Muscle 1: Muscles Acting on Humerus

Crossing shoulder joint to humerus - 2 arise from axial skeleton (prime movers in flexion and extension) - Arise from sternum and clavicle or T7-L5 and ilium - Pectoralis Major - Lastissimus Dorsi

Muscle 3: Striations = Organization of Filaments

Dark A bands (regions) alternating with lighter I bands (regions) - Anisotrophic (A) and isotropic (I) stand for the way these regions affect polarized light A band is thick filament region - Lighter, central H band area contains no thin filaments I band is thin filament region - Bisected by Z disc protein called connectin, anchoring elastic and thin filaments - From one Z disc (Z line) to the next is a sarcomere

Muscle 1 Location of Fascia

Deep fascia - Found between adjacent muscles Superficial fascia (hypodermis) - Adipose between skin and muscles

Muscle 1: Connective Tissue of Muscle

Deep to Superficial (strong to delicate): 1. Epimysium - Wraps a group of fascicles (the entire muscle) and forms the functional muscle 2. Perimysium - Wraps a group of muscle fibers into a bundle called a fascicle 3. Endomysium - Wraps each muscle fiber (cell) 4. Deep Fascia - Sheet of connective tissue separating adjacent muscles 5. Superficial Fascia (a.k.a. - hypodermis) - Sheet of connective tissue separating muscle from skin - All help to protect and strengthen muscle Notes: - To form muscles, lots of muscle fibers make it with various muscle covers. - Fascial is held together by perimysium. Can be seen by naked eye (fat white parts of meat) - Muscles are next to muscles; muscles are on top and under muscle. (Many layers)

Muscle 1: Suprahyoid Muscles and Swallowing

Digastric and Mylohyoid = open mouth Geniohyoid = widens pharynx during swallowing Stylohyoid = elevates hyoid Thyrohyoid = elevates larynx, closing glottis

Muscle 1: Muscle Attachments (Part 2)

Direct (fleshy) attachment to bone - Epimysium is continuous with periosteum - Intercostal muscles Indirect attachment to bone (Vast Majority of Muscles) - Epimysium continues as tendon or aponeurosis that merges into periosteum as perforating fibers - Biceps brachii or abdominal muscle Stress will tear the tendon before pulling the tendon loose from either muscle or bone Notes: - Tendons are the primary way that muscles attach. - Direct Attached Muscles *Fleshy attachments *Ex: costal cartilage in ribs open slightly allowing lungs to expand when breathing

Muscle 3: Anaerobic ATP Formation

Does not use oxygen - Happens in oxygen and no oxygen environment Glycolysis (glucose 2 pyruvic acid + 2 ATP) - Pyruvic Acid = Lactic Acid Some enters oxygen pathway in mitochondria to make 36 ATP - 2 minutes worth usually However, when muscle contract vigorously— - Muscles compress BV - No oxygen and glucose present - Thus, pyruvic acid turns into lactic acid pathway called anaerobic glycolysis - Lactic acid is end product - Liver turns LA back to PA No oxygen pathway—only 5 % as much ATP as with oxygen, but 2.5x faster than oxygen pathway Lactic acid leads to muscle fatigue and soreness The burning sensation is caused by a build up of lactic acid

Muscle 3: ADP + CP (Phosphagen System)

Exercise—use ATP fast, depleted source ATP reserves used up in 2 seconds so need to then use CP Creatine phosphate: - High energy molecule - Stored in muscles - Regenerates ATP - CP + ADP = ATP CP reserves exhausted quickly ATP + CP—maximum muscle power - 15-20 seconds

Muscle 1: Rotator Cuff Muscles - SITS

Extending from posterior scapula to humerus - Supraspinatus - Infraspinatus - Teres minor Extending from anterior scapular to humerus - Subscapularis All 4 help to reinforce joint capsule

Muscle 1: Anterior Compartment of Leg

Extensor digitorum longus = extension of toes and ankle Extensor hallucis longus = extension of big toe and ankle Fibularis longus/brevis = dorsiflexes and everts foot Tibialis anterior = dorsiflexes and inverts foot

Muscle 1: Muscles of Respiration: Intercostals

External intercostals - Extend downward and anteriorly from rib to rib - Pull ribcage up and outward during inspiration Internal intercostals - Extend upward and anteriorly from rib to rib - Pull ribcage downward during forced expiration

Muscle 1: Epimysium

Fibrous dense irregular connective tissue sheath Surrounds entire muscle (Biceps brachii) Outer part Blends into the deep fascia Notes: - Epi = on or above - Mys = muscles - More robust

Muscle 3: Muscle Contraction and Relaxation

Four actions involved in this process - Excitation = nerve action potentials lead to action potentials in muscle fiber - Excitation-contraction coupling = action potentials on the sarcolemma activate myofilaments - Contraction = shortening of muscle fiber - Relaxation = return to resting length Images will be used to demonstrate the steps of each of these actions

Muscle 3: Neuromuscular Junctions (Synapse)

Functional connection between nerve fiber and muscle cell Neurotransmitter (acetylcholine/ACh) released from nerve fiber stimulates muscle cell Components of synapse (NMJ) - Synaptic knob is swollen end of nerve fiber (contains ACh) - Junctional folds region of sarcolemma *Increases surface area for ACh receptors *Contains acetylcholinesterase that breaks down ACh and causes relaxation - Synaptic cleft = tiny gap between nerve and muscle cells Basal lamina = thin layer of collagen and glycoprotein over all of muscle fiber In Class Notes: - AcH is stored in the synaptic knob. *There has to be receptors to receive what is releases. - Synaptic cleft = gap - Action potential = electrical charge *This causes ion channels to open and release its contents.

Muscle 1: Muscle Shapes

Fusiform - Thick in the middle and taper at both ends (biceps brachii) Parallel - Uniform width of parallel fascicles (Sartorius) relatively weak but can span long distances Convergent - Fan shaped muscle with wide origin and narrow insertion (Pectoralis Major) Pennate - Feather shaped, have muscle fibers attached obliquely to a tendon = more muscle fibers/length of muscle (Rectus Femoris) - Most Powerful Circular - Rings around body openings (anal sphincter) Notes: - Parallel muscles don't have a thick middle. - Convergent muscles are very strong since fibers are crossing in different directions

Muscle 2: Atlas B (Surface Anatomy)

Importance of External Anatomy Trunk - Thorax & abdomen, back & gluteal region, pelvic & axillary region, Upper Limb - Lateral aspect, antebrachium (forearm), wrist & hand Lower Limb - Thigh & knee, leg, foot Muscle Test

Muscle 3: Isometric and Isotonic Contractions

Isometric muscle contraction - Develops tension without changing length - Important in postural muscle function and antagonistic muscle joint stabilization Isotonic muscle contraction - Tension while shortening = concentric - Tension while lengthening = eccentric

Muscle 3 Thick Filaments

Made of 200 to 500 myosin molecules - 2 entwined polypeptides (golf clubs) Arranged in a bundle with heads directed outward in a spiral array around the bundled tails - Central area is a bare zone with no heads

Muscle 3: Aerobic Respiration (with oxygen)

Mitochondria Need oxygen Bonds broken to release energy to make ATP Glucose + oxygen = carbon dioxide + water+ ATP One glucose makes 36 ATP - Have about 40 minutes worth of glucose to use aerobically—then go to fat and other energy stores Slow, many steps, need much oxygen and many nutrients 95% of ATP made this way

Muscle 1: The Functions of Muscles

Movement of body parts and organ contents Maintain posture and prevent movement Communication - speech, expression and writing Control of openings and passageways Heat production - Metabolic process of muscles

Muscle 3: Muscle Fibers

Multiple flattened nuclei inside cell membrane - Fusion of multiple myoblasts during development - Unfused satellite cells nearby can multiply to produce a small number of new myofibers Sarcolemma has tunnel-like infoldings or transverse (T) tubules that penetrate the cell - Carry electric current to cell interior Sarcoplasm is filled with - Myofibrils (bundles of myofilaments) - Glycogen for stored energy and myoglobin for binding oxygen Sarcoplasmic reticulum = smooth ER - Network around each myofibril - Dilated end-sacs (terminal cisternea) store calcium - Triad = T tubule and 2 terminal cisternea Notes: - Muscles store sugars to help with movement and overall function. - Electricity opens channels which releases the ions. In Class Notes: - Transverse tubules go across the sarcolemma. - Terminal cisternae has calcium. *When the electrical charge goes through the transverse tubules, it opens up the terminal cisternae which then releases calcium. - Skeletal muscles store glycogen (glucose). - Sarcoplasmic reticulum *Holds the terminal cisternae (stores calcium) and T tubule *Smooth ER + T Tubule + 2 Terminal Cisternae = Triad

Muscle 3: Relaxed and Contracted Sarcomeres

Muscle cells shorten because their individual sarcomeres shorten - Pulling Z discs closer together - Pulls on sarcolemma Notice neither thick nor thin filaments change length during shortening Their overlap changes as sarcomeres shorten In Class Notes: - Sliding filament theory: the actin and myosin slide past each other; they do not shorten.

Muscle 3: Regulatory and Contractile Proteins

Myosin and actin are contractile proteins Tropomyosin and troponin = regulatory proteins - Switch that starts and stops shortening of muscle cell - Contraction activated by release of calcium into sarcoplasm and its binding to troponin, - Troponin moves tropomyosin off the actin active sites In Class Notes: - Myosin and Actin = contractile protein *Slide past each other - Tropomyosin and Troponin = regulatory proteins *Don't slide past each other

Muscle 3: Breakdown/Review (Part 2)

NO OXYGEN: + (no need oxygen) - (low amount of ATP made, end product toxic - lactic acid, high level fatigue) OXYGEN: + (high amount of ATP made, no toxic) - (need oxygen) Each ATP pathway depends on needs: - Immediate energy: CP (100 dash) - Short term: *Glycogen-lactic acid system (no oxygen) Glucose from blood and stored glycogen *30-40 seconds of activity—maximum of 2 minutes *Run around baseball diamond - Long term: Respiratory & Cardiovascular systems catch up (oxygen)

Muscle 2: Importance of External Anatomy

Necessary for physical examination & many medical procedures - Physical therapy - CPR - X rays - Injections - Pulse - Pressure points - Electrocardiograms

Muscle 3: Lance Armstrong Case Study

Needs long term muscle contraction - He rides 100+ miles Most people only have enough reserves for 40min. of aerobic respiration - After 40min. other sources are used; fatty acids, fats & finally muscle Lactic Acid builds up in an anaerobic environment Needs long term muscle contraction - He rides 100+ miles Lance Carb-loads night before Eats during his ride Keep target heart rate low - Around 120 beats/min body uses fat more readily than carbohydrates (Even athletes have enough fat reserves to push them through a race) - Extends glucose reserves for the hills 7 Time Winner Tour de France: How? - Average Joe's maximum oxygen uptake (VO2max) is 35ml/min/kg - Elite athletes can have VO2max of 70ml/min/kg - Lance's VO2max is 83.8ml/min/kg (One of the highest in the world! - Why do we care? *More oxygen = more ATP = less fatigue = more muscle contraction 7 Time Winner Tour de France: How? - He trains at high altitudes & with high altitude tent - Body adjust by producing more erythrocytes in low oxygen environment = more oxygen transfer to muscles = more ATP = less fatigue = more muscle contraction 7 Time Winner Tour de France: How? - Through his training he has acquired the ability to stay in aerobic respiration longer than his competitors, reducing lactic acid build up and muscle fatigue

Muscle 1: How Muscles are Named

Nomina Anatomica - System of Latin names developed in 1895 - Updated since then English names for muscles are slight modifications of the Latin names. Examples of terms used to name muscles - levator = elevates a body part - profundus = deepest - quadriceps = having 4 heads Notes: - Levator Scapula Muscle —> Elevates the scapula - Muscles of the forearms are named the same but differentiated as superficial or deep.

Muscle 1: Parts of a Skeletal Muscle

Origin - attachment to stationary end of muscle Belly - Thicker, middle region of muscle Insertion - attachment to mobile end of muscle Notes: - 3 muscles of the brachial region - Muscles are thicker in the middle *Tapors at the ends (attachment sites) - Origin of the brachii is at the top, attachment at the bottom, belly in the middle

Muscle 3: Neuromuscular Toxins

Pesticides (cholinesterase inhibitors) - Bind to acetylcholinesterase and prevent it from degrading ACh - Spastic paralysis and possible suffocation Tetanus or lockjaw is spastic paralysis caused by toxin of Clostridium bacteria - Blocks glycine release in the spinal cord and causes overstimulation of the muscles Flaccid paralysis (limp muscles) due to curare that competes with ACh - Respiratory arrest

Muscle 3: Electrically Excitable Cells

Plasma membrane is polarized or charged - Resting membrane potential due to Na+ outside of cell and K+ and other anions inside of cell - Difference in charge across the membrane = resting membrane potential (-90 mV cell) Stimulation opens - Ion gates in membrane ion gates open (Na+ rushes into cell and K+ rushes out of cell) *Quick up-and-down voltage shift = action potential - Spreads over cell surface as nerve signal Notes: - Kicks out sodium, Brings in potassium

Muscle 1 Muscle Actions during Elbow Flexion

Prime mover (agonist) = brachialis Synergist = biceps brachii Antagonist = triceps brachii Fixator = muscle that holds scapula firmly in place - Rhomboideus m. Notes: - Scapula are freely moveable. - Fixators hold the scapula in their place.

Muscle 1: Coordinated Muscle Actions

Prime mover or agonist - Produces most of force Synergist - Aids the prime mover - Stabilizes the nearby joint - Modifies the direction of movement Antagonist - Opposes the prime mover - Preventing excessive movement and injury Synergist - Aids the prime mover by reducing undesirable movement Fixator - (Specialized synergist) prevents movement of bone Notes: - Muscles are categorized based on their flexions/movements. - Agonists and Antagonist oppose each other. - Fixators "fix" something into place.

Muscle 1: Muscles Acting on Elbow

Principal flexors - Biceps brachii (inserts on radius) - Brachialis (inserts on ulna) - Synergistic flexor (brachioradialis) - Prime extensor (triceps brachii inserts onto ulna)

Muscle 1: Hernias

Protrusion of viscera through muscular wall of abdominopelvic cavity Inguinal hernia - Most common type of hernia (rare in women) - Viscera enter inguinal canal or even the scrotum Hiatal hernia - Stomach protrudes through diaphragm into thorax - Overweight people over 40 Umbilical hernia - Viscera protrude through the navel Notes: - Hernia is a weakness/tear in the body wall that pokes out. - Umbilical hernia —> middle muscle of the abdomen.

Muscle 1: Rectus Abdominis and External Oblique

Rectus Abdominis: - Vertical, straplike - Tendinous intersections - Rectus sheath - Linea alba External Oblique: - Superficial - Downward - Anteriorly - Inguinal Ligament Notes: - Oblique = on an angle

Muscle 1: Posterior Scapular Muscles

Rhomboideus mm. - Medial border of scapula to C7-T1 Levator Scapulae - From superior angle of scapular to C1-C4

Muscle 3: Nerve-Muscle Relationships

Skeletal muscle must be stimulated by a nerve or it will not contract Cell bodies of somatic motor neurons in brainstem or spinal cord Axons of somatic motor neurons = somatic motor fibers - terminal branches supply one muscle fiber Each motor neuron and all the muscle fibers it innervates = motor unit Notes: - Calf = large motor unit - Hand = small motor unit Class Notes: - Motor = leading to movement (things leavings and going to the effector) *The neuron and all the nervous fibers. - Neurotransmitter binds to a receptor on the sarcolemma.

Muscle 3: Elastic Filaments

Springy proteins called titin Anchor each thick filament to Z disc Prevents overstretching of sarcomere In Class Notes: - Titin is a protein that keeps the myosin attached to the Z disc

Muscle 3: Excitations Steps

Steps 1 and 2: Nerve signal opens voltage-gated calcium channels. Calcium stimulates exocytosis of synaptic vesicles containing ACh = ACh release into synaptic cleft. Steps 3 and 4: Binding of ACh to receptor proteins opens Na+ and K+ channels resulting in jump in RMP from -90mV to +75mV forming an end-plate potential (EPP). Step 5: Voltage change in end-plate region (EPP) opens nearby voltage-gated channels producing an action potential Steps 6 and 7: Action potential spreading over sarcolemma enters T tubules -- voltage-gated channels open in T tubules causing calcium gates to open in SR Steps 8 and 9: Calcium released by SR binds to troponin Troponin-tropomyosin complex changes shape and exposes active sites on actin Steps 10 and 11: Myosin ATPase in myosin head hydrolyzes an ATP molecule, activating the head and "cocking" it in an extended position Steps 12 and 13: - Power stroke = myosin head releasesADP and phosphate as it flexes pulling the thin filament past the thick - With the binding of more ATP, the myosin head extends to attach to a new active site *Half of the heads are bound to a *Thin filament at one time preventing slippage thin and thick filaments do not become shorter, just slide past each other (sliding filament theory) Steps 14 and 15: Nerve stimulation ceases and acetylcholinesterase removes ACh from receptors. Stimulation of the muscle cell ceases. Step 16: Active transport needed to pump calcium back into SR to bind to calsequestrin ATP is needed for muscle relaxation as well as muscle contraction Steps 17 and 18: - Loss of calcium from sarcoplasm moves troponin-tropomyosin complex over active sites *Stops the production or maintenance of tension - Muscle fiber returns to its resting length due to recoil of series-elastic components and contraction of antagonistic muscles

Muslce 3: Rigor Mortis

Stiffening of the body beginning 3 to 4 hours after death Deteriorating sarcoplasmic reticulum releases calcium Calcium activates myosin-actin cross-bridging and muscle contracts, but can not relax. Muscle relaxation requires ATP and ATP production is no longer produced after death Fibers remain contracted until myofilaments decay

Muscle 1: Supination and Pronation

Supination - Supinator muscle - Palm facing anteriorly Pronation - Pronator teres and Pronatior quadratus mm. - Palm faces posteriorly

Muscle 1: Intrinsic Hand Muscles

Thenar group = fleshy base of thumb muscles Hypothenar group = base of little finger muscles Midpalmar group = Interosseus mm. and Lumbrical mm.

Muscle 1: Perimysium

Thicker sheath of dense irregular connective tissue Wraps 10-100 muscle fibers into fascicles (visible to the naked eye) Carries larger nerves/vessels and special stretch receptors called muscle spindle fibers Notes: - Surrounds fascicles - Holds nerves and vessels in place - Carries large muscles and nerves

Muscle 1: Endomysium

Thin sheath of loose areolar connective tissue Creates room for capillaries & nerve fibers - Ensures each muscle fiber is nourished Provides extracellular chemical environment for the excitation of the muscle fiber by the nerve - Excitation is based on the exchange of ions between endomysial fluid, the nerve & muscle fiber Notes: - Tendon is a continuation of connective tissues. - Endomysium = beginning/small layer. - Endomysium surrounds the muscles, insulates it, helps hold capillaries and neurons, keeps close contact to muscle fibers, provides extracellular chemical environment for muscle stimulation, and more.

Muscle 3: Thin Filaments

Two intertwined strands fibrous (F) actin - Globular (G) actin with an active site Groove holds tropomyosin molecules - Each blocking 6 or 7 active sites of G actins One small, calcium-binding troponin molecule on each tropomyosin molecule In Class Notes: - Actin has the compliment of the "golf ball heads" (aka myosin head). *Myosin heads stretch out and bind to the actin and pull. - Tropomyosin hides the binding site. *Calcium will meet troponin complex, moving it and the tropomyosin to rotate out of the way, which allows myosin to leave and bind to the actin. - Easier Version of Contraction *Actin with Binding Sites *Myosin Needs to Bind *Actin Binding Sites Covered (not contracting) *Myosin Binds when Tropomyosin Moves - 1 Neuron stimulates 1 Muscle Cell.

Muscle 1: Athletic injuries

Vulnerable to sudden and intense stress Proper conditioning and warm-up needed Common injuries - Shinsplints - Pulled hamstrings - Tennis elbow Treat with rest, ice, compression and elevation (RICE) "No pain, no gain" is a dangerous misconception Notes: - Shinsplints is inflammation that makes you feel like you broke a bone, but you actually didn't. - Tennis elbow is because of overuse.