anatomy test 3

important enzymes

LPL(lipoprotein lipase) and HSL(hormone sensitive lipase)

LPL (lipoprotein lipase)

found on the cell membrane, helps bring fatty acids (FA) into the cells. It stores carbs as glycogen in liver and muscles

HSL(hormone sensitive lipase)

found inside fat cells. breaks down stored fat (triglycerides), into FA so they can escape into circulation and be available for muscle cells to burn for fuel.

High insulin levels can cause LPL on fat cells to become

more active

High insulin levels can cause LPL on muscle cells to become

less active

High insulin levels can cause HSL to become

less active.

What causes high insulin levels

anything with a sweet taste

Skeletal Muscle is made up of

multinucleated muscle cells aka fibers nundles in fasciles

Thick and thin filaments make up

myofibril

myofibrils make up

muscle cell/fiber

muscle cells/fibers make up

a fascicle

fasicles make up

a muscle

muscle cells (fibers) are covered by

endomysium

Groups of muscle fibers are called a fascile and are covered by

perimysium

Group of fascicles are called muscles and are covered by

epimysium

the epimysium is covered by

fascia

the function of muscle coverings

provides pathways for blood and lymph vessels, gives multiple attachments to bones; creating strength, makes a slippery sleeve to prevent friction

tendon

CT cord; made of all CT coverings attaching muscle to bone

Aponeurosis

broad flat sheet of CT connecting muscle to bone (pectoralis major)

tendon sheaths (coverings/retinaculum)

tube like sturcture enclosing tendons; notably wrists and ankles(carpaltunnel and tarsal tunnel)

strain

injury of muscle or tendon by overstretching or overexertion

sprain

injury of ligaments

endomysium covers

Sarcolemma

origin

point or points of attachment that do NOT move

Insertion

points of attachment that DO move

Insertion

always move TOWARD origin

Prime Mover/Agonist

contracts and directly performs a specific action or movement. (biceps brachii)

Antagonist

performs an opposite action to PM. it relaxes when PM contracts. (triceps brachii)

Synergist/helper

Contracts at the same time as PM and helps with the action. (brachioradialis)

Fixator

joint stabilizer; fixator muscles of neighboring joint act to maintain posture or balance. shortening of muscle is too slight to notice. Theyre type of synergists, contraction w/ no visible movement-maintaing posture/balance. (shoulder muscles)

Lever(bone in human body)

any rigid bar thats free to turn around a fixed point,fulcrum or pivot to move a load

pivot is a

joint

Components of lever that sometimes change position

• (F)ulcrum or pivot point

• (L)oad or weight

• (P)ushing or pulling force

Class 1 lever

like a sesaw or tilting the head back

class 2 lever

like lifting and pulling a wheelbarrow or standing on toes

class 3 lever

flexing the forearm at the elbow as in lifting weight or lifting load with a shovel

how muscle are named by shape

• trapezius/table/4footed

• deltoid/triangle

how muscles are named by

location/region

how muscles are named by size:

gluteus maximus

• medius

• minimus

muscles can be named by

• action,

• point of attachment

• number of divisons

• direction of muscle fibers

Buccinator

located in the cheeks; smiling,blowing,sucking

masseter

located in the cheeks; jaw closure

sternocleidomastoid

located in the neck; head flexion/rotation

rectus abdominis

located in the abdomen; trunk flexion/bending

trapezius

located in the shoulder/upper back; extends head/shrugs shoulders

pectoralis major

located in the chest;hug muscle/anterior arm adduction

latissimus dorsi

located in the back; posterior arm adduction

deltoid

located in the shoulder;arm abduction/lifting

biceps brachii

located in the upper arm; flexes forearm

triceps brachii

located in the upperarm; extends forearm

iliopsoas

• psoas minor

• iliacus

• psoas major

located in thigh/deep; lift leg/trunk flexion

gluteus maximus

located in the buttocks; thigh extension/rotation

adductor group:

• adductor brevis

• adductor longus

• adductor magnus

located in inner thigh; adduct,rotate,flex thigh

quadriceps:

• rectus femoris

• vastus lateralis

• vastus medialis

• vastus intermedius

located in the thigh; leg extension/kicking motion

sartorius

located in the thigh; leg flexion,crossing; LONGEST MUSCLE

hamstrings:

1. bicep femoris

2. semitendinosus

3. semimembranosus

1. lateral

2. superficial

3. deep

loacted in thigh;leg flexion/bending

tibialis anterior

located in anterior lower leg ; dorsiflexion/pull foot up

gastrocnemius

located in posterior lower leg; plantar flexion/pointed toe

soleus

located depp to gastroc

functions of muscles

• movement

• heat production

• posture

charcterestics of muscle fibers

• excitable

• contractible

• extensible/stretchable

muscle fiber/muscle cell components

• sarcolemma

• T-tubules

• sarcoplasmic reticulum

• myofibrils

• sarcomere

• myofilaments

sarco means ____ and myo means _____

flesh and muscle

sarcolemma

cell membrane

T-tubules

transverse tubules; transport nerve impulse deep into muscle fiber

sarcoplasmic reticulum/SR

smooth ER of the muscle, stores calcium

Myofibrils

smaller units of muscle fiber that contains Sarcomeres

Sarcomere

segement of Myofibril between Z-lines; Functional contractile unit

Myofilaments

smaller unit of Myofibril or Sarcomere; made up of proteins that create striations

thick filaments

myosin(cross-bridges)

thin filaments

mostly actin,also troponin and tropomyosin

sliding filament theory(1st step)

nerve impulse travels down the axon of a motor neuron

sliding filament theory (2nd step)

impulse reaches the neuromuscular junction (synapse)

sliding filament theory (3rd step)

Nerve impulse triggers the release of Acetylcholine/ neurotransmitter from motor neuron

sliding filament theory (4th step)

Acetylcholine travels across the synapse and binds to receptors on the motor end-plate of the muscle fiber

sliding filament theory (5th step)

Impulse travels along the Sarcolemma into T-tubule to SR. (this impulse changes membrane permeability to NA+ and K+ ions which generate AP of muscle excitation)

sliding filament theory (6th step)

Calcium is released into the SR

sliding filament theory (7th step)

Calcium binds to Troponin on thin filament

sliding filament theory (8th step)

Tropomyosin molecules in thin filament shift their position exposing Actins binding site to Myosin

sliding filament theory (9th step)

Myosin cross-bridges bind to Actin and pull thin filaments toward center of Sarcomere

sliding filament theory (10th step)

thin filaments slide past thick filaments = muscle fiber shortens

rigor mortis

stiffness of death

how rigor mortis happens

• muscles begin to stiffen 3-4 hours after death

• Calcium floods muscle cell

• enough stored ATP causes binding of Myosin & Actin

muscle atrophy

muscle shrinks and weakens from non-use

muscle tone

partial muscle contraction even when muscle is at rest. important for maintaining posture

muscle flaccidity

muscle isnt contracted (soft), lack of nerve supply

myalgia

muscle pain without myopathy

myopathy

any or all pain, stiffness, weakness or wasting

acetylcholine

exictatory or inhibitory neurotransmitter, depending on the receptors at the location. Exicatory: starts an action. Inhibiatory stops an action

Clostridial Neurotoxins (bacteria)

• botulism:blocks excitatory Acetylcholine receptors, resulting in flaccid paralysis

• tetanus:blocks inhibitory Acetylcholine, resulting in spastic paralysis/lock jaw

Myasthenia Gravis "grave muscle weakness”

autoimmune disorder, immune system destroys ACh receptors starting the face

Slow/red fiber

slow contractions; gives more time to produce ATP/fatigue resistant

• ex:postural muscles

• excersize:aerobic long-distance

fast/white fiber

rapid contractions;run out of ATP quickly/fatigable/strong force of short duration

• ex:finger and eye muscles/rapid short term movements

• excersize:weight lifting

intermediate/pink fiber

characterstics between red and white fibers

• ex:postural muscles that occasionally required to generate rapid powerful contractions;leg muscles

• excersize: aerobic short distance/soccer/tennis

motor-neuron

non sensory nerve (efferent)

motor endplate

the part of the muscle across the synapse from the neuron

motor unit

the nerve and the muscle it works with

principiles that govern motor units

1. all muscle fibers of same unit are controlled together

2. motor units fire in overlapping fashion like relay team; produce contraction & prevent fatigue

3. recruitment:motor units in a muscle are enlisted as demand increases

muscle fatigue is caused by

when muscle runs out of nutrients and elevated levels of lactic acid result from it