Muscle Rules
Classification by Size: • Gluteus maximus is the largest muscle in the group • Gluteus minimus is the smallest in the group
Gluteus maximus and Gluteus minimus
cross-striations occur in the fibers as a result of regular overlapping of thick and thin myofilaments
Striated Muscle
Actin and Myosin Muscle contraction occurs when these filaments slide over one another in a series of repetitive events.
Striated Muscle has two major protein filaments
two, joint
There are at least ___ attachments and the muscle will cross a __ at the elbow
thick filament
myosin
180 degrees angle gets smaller
straight arm starts at ___ degrees, but as you flex the angle gets ___
Classification by number of origins: • Biceps brachii has two origins on the scapula • Triceps brachii has three origins on the humerus
Biceps Brachii and Tricps Brachii
flexes elbow
Brachial Muscle action
proximal ulna
Brachial Muscle insertion
• halfway down the humerus • not medial and lateral of radial grove
Brachialis Muscle origin
A muscles structure consists of connective tissue and muscle fibers, which work like a rope or rubber band to stretch and contract. The connective tissues' elasticity helps to ensure that the tension developed by the muscle is smoothly transmitted and that a muscle will return to its original shape after being stretched.
Describe how the structural makeup of a muscle contributes to the muscle's ability to do its job
Skeletal muscle - striated and looks like long fibers. Cardiac muscle- striated and has visible nuclei. Smooth muscle non-striated and has a wave type structure with visible nuclei
Describe the differences you see in the three types of muscle tissues.
yes
Does skeletal muscle has striations?
The insertion of the muscle is the end of the muscle attaching to the freely moving bone. The origin of the muscle is the end of the muscle attaching to the fixed, non-moving bone.
Explain how you know which attachment of a muscle is the origin and which attachment is the insertion.
Classification by action: • Flexor carpi ulnaris flexes the hand at the wrist • Extensor digitorium longus extends the foot and toes upward
Flexor Carpi Ulnaris and Extensor digitorum longus
decrease the angle between ventral surfaces
Flexors
No because when the flexors are pulling, the extensors are relaxing.
For smooth movements to occur, can both extensors and flexors be contracting at the same time?
Classification by location in the body: • Frontalis is located on the frontal bone of the skull • Temporalis is located on the temporal bone of the skull
Frontalis and Temporalis
As you flex your arm, the brachialis muscle pulls you lower arm up as the muscle contracts and gets shorter.
Rule #2 example
Brachialis Muscle • Origin = halfway down the humerus (both medial and lateral of the radial groove) [Stationary] • Insertion = proximal ulna [Movable]
Rule #3 example
flex your arm - brachialis muscle - flexor. extend your arm - brachii muscle - extensor.
Rule #4 example
Brachialis is a flexor and brachii is an extensor. They are opposing pairs since they cause the arm to move in opposite directions.
Rule #5 example
Long stringy lines that extend from one point of attachment to the other, but become narrower near the point of origin since the bone will be pulled towards the point of origin.
Rule #6 example
Brachialis Muscle • Origin = halfway down the humerus (both medial and lateral of the radial groove) • Insertion = proximal ulna • Crosses the elbow joint
Rule 1 example
helps move the scapula forward and is often used at the end of big movements such as a bench press, a baseball pitch, or a swimming stroke.
Serrates Anterior action
medial border of the scapula
Serrates Anterior insertion
lateral surface of ribs 1-8 (bone only)
Serrates Anterior origin
striated muscle tissue voluntary control somatic nervous system tendons
Skeletal Muscle
blood vessels and hollow internal organs, such as the stomach, intestine, and bladder involuntary not striated
Smooth Muscle
Classification by origin and insertion: • Sternocleidomastoid has origins on the breastbone (sternum) and the collage bone (clavicle or "cleido") and insertions of the mastoid process of the skull's temporal bone • Brachioradialus has an origin on the brachium or arm and an insertion on the radius
SternoCleidomastoid and Brachioradialis
yes
are there striations in Cardiac Muscle
point to the attachments and show the direction of pull
striations
attachment that moves
insertion
no
is cardiac muscle voluntary
No
is sooth muscle voluntary
smooth muscle connective tissue because its function is to surrounds muscle fibers and fascicles, connecting them and helping them retain shape
what type of tissue do you think makes up the three layers of membrane you encountered in your muscle?
involuntary striated
Cardiac Muscle
no
does smooth muscle have striations?
extends elbow
triceps brachii action
Rule #1: Muscles must have at least two attachments and must cross at least one joint. Rule #2: Muscles always "pull" and get shorter. Rule #3: The attachment that moves is known as the insertion and the attachment that remains stationary is known as the origin. Rule #4: Muscles that decrease the angle between ventral surfaces of the body are known as flexors. Muscles that increase the angle between ventral surfaces of the body are known as extensors. Rule #5: Muscles work in opposing pairs. Rule #6: Muscle striations point to the attachments and show the direction of pull.
6 Muscle Rules
Rule 1: two attachments one joint Rule 2: only pull Rule 3: insertion and origin Rule 4: flexor and extensor Rule 5: opposing pairs Rule 6: striations
6 muscle rules, my version
Thin filament
Actin
Another muscle must pull to get the arm back to 180°.
If muscles can only be pulled, then how does a flexed arm go back to being straight?
Attachment that moves
Insertion
Yes
Is skeletal muscle a voluntary muscle?
attached to bones
Location of skeletal muscle
PULL
MUSCLES ONLY ___
Classification by direction of fibers: • Fibers in orbicularis oculi form a circle • Fibers in transverse abdominis "traverse" or go across the abdomen
Orbicularis Oculi and Transverse abdominis
Stationary
Origin
to rotate the shoulder forward.
Pectoralis minor action
coracoid process of the scapula (piece of the scapula visible on the front
Pectoralis minor insertion
anterior surface of ribs 3 - 5 (just past the origins of the serratus anterior)
Pectoralis minor origin
tennis serve or a volleyball spike Downward motion
Pectorals Major action
lateral edge of the most proximal part of the humerus
Pectorals Major insertion
ribs 5-7 (actually attaches to fascia of abdominal muscles)
Pectorals Major origin
Classification by Shape: • Trapezius is shaped like a trapezoid • A rhomboid is shaped like a rhombus
Trapezius and Rhomboid minor
Involuntary muscle contraction is when muscles contract without a conscious effort, like the heart beating or digestion of food
What does it mean when we say a muscle contracts involuntarily? Describe one body function that is linked to an involuntary muscle contraction.
Shivering causes you to involuntary contract and relaxes your muscles which will increase heat production, keeping the body at a stable 98.6 degrees F
When you are cold, your muscles begin to contract involuntarily and cause you to shiver. Why do you think this occurs? How does the contraction of muscles help the body maintain homeostasis?
ulnar pulled humeral stationary
When you bend your forearm, the __ attachment is being pulled, and the ___ attachment stays stationary
She has injured the muscle on the backside of her tibia. This muscle acts to dorsiflex and invert the foot
Your mom comes back from the doctor and says she has pulled her tibialis anterior. She knows you are taking Human Body Systems and asks you to tell her about her injury. Based on the classroom discussion, what can you deduce about this muscle?
controls motion at a joint that increases the angle between articulating bones
extensor muscle
Muscles that increase the angle between ventral surfaces
extensors
muscle at a joint that decreases the angle between articulating bones
flexor muscle
flexors - ventral extensors - dorsally
flexors are on the ___ side of the body, and extensors are on the __ side
heart contractions
function of cardiac muscle
movement, heat, posture
function of skeletal muscle
Movement of Blood Through Vessels, Food through Digestive system
function of smooth muscle
heart
location of cardiac muscle
Lines blood vessels and hollow internal organs, such as the stomach, intestine, and bladder
location of smooth muscle
• attachment that does not move • pulls the other attachment toward it • usually the proximal attachment
origin
extensor
triceps brachii flexor or extensor
distal of elbow on the ulna
triceps brachii insertion
proximal half of dorsal humerus
triceps brachii origin