Exam 2 muscles

What does myosin want to bind with

actin

Trypomyosin

a protein that blocks myosin binding sites on actin filaments

Troponin complex

Regulates muscle contraction by binding calcium ions and moving tropomyosin. It is on a hinge, and opens to move the tropomyosin

What is released causing a confirmation change

Calcium ions

What happens during the calcium confirmation change

Calcium moves out and troponin closes

The energy from calcium causes myosin to

Cock (pivot into high energy position) to get ready to bind to actin

What causes rigor mortis

At death the sarcoplasmic reticulum falls a pert first, causing a great surge of calcium causing it to become (stiff)

what makes up a belly of muscle

fibers

Most of the fibers in the belly muscle are

overlapping

How do the fibers work

by contracting (shortening) and the force of contracting comes from (transmitted by) tendons

Muscle origin

site of attachment closer to the midline

All muscles have insertation

site of attachment away from the midline

coraco-

chest/pectoral

mandibul

jaw

Muscles work in

antagonistic pairs → oppositte actions

flexion (biceps)

decrease angle

extension (triceps)

increase angle

How do muscle names work

you use the names of the action of the muscle

Origin + insertation

• coracomandibularis

• xiphihumeralis

• sternomastoid

• cleidomastoid

cleido

clavicle

xiphi

sternum

number of heads or origins

biceps vs triceps

depth of muscle

• pectoralis profundus

• flexor digitorum superficialis

Pectoralis profundus

deep

flexor digitorum superficialis

shallow

Relative position of muscle

• lateral

• medial head of triceps (closer to midline)

Length of tendon

• adductor pollicis longus

• adductor pollicis brevis

Adductor pollicis longus

long

adductor pollicis brevis

short

pollicis

thumb

Action of muscles

• flexor digitorum profundus

• extensor digitorum communis

Flexor digitorum profundus

forearm muscle that flexes the fingers.

Extensor digitorum communis

posterior forearm muscle that extends the fingers.

what is the goal of skeletal muscles

to move the bone

Ratio of the input to output is small

This allows for fast motion but it is a weak strength

Larger input length than its output length

this ratio optimizes strength

muscles operate by

lever system

Changing where a muscle is on a bone changes what

Mechanics

• speed vs. strength

• distance