HBS 4.2 Quiz

Explain how you know which attachment of a muscle is the origin and which attachment is the insertion.

The origin is the attachment that remains stationary during muscle contraction. The insertion is the attachment that moves during muscle contraction.

Explain how the muscles pectoralis major and serratus anterior show two different ways in which muscles are named.

The pectoralis major is named based on muscle size. It is the bigger muscle out of the pectoralis muscles. (You don't really need to know this, but note that maximus, minimus, and medius are used when there are three muscles whose sizes are being compared; and major/minor are used when there are two muscles whose sizes are being compared.) Serratus anterior gives you a relative location in the body. Based on the name of this muscle, you at least know that the muscle is on the front of the body.

Name the 6 muscle rules

Muscles must have at least 2 attachments and must cross at least one joint Muscles always pull and get shorter (they contract) The attachment that moves is the insertion and the attachment that remains stationary is the origin Muscles that decrease the angle between ventral surfaces are known as flexors; muscles that increase the angle between the ventral surfaces are known as extensors Muscle always work in opposing pairs Muscle striations point to the attachment and show the direction of pull

Serratus Anterior: Origin, insertion, action, location

Origin - Ribs 1-8 Insertion - medial border of scapula Action - moves the shoulder blade forward Sport - tennis groundstrokes Chest under armpits

Pectoralis Minor: Origin, insertion, action, location

Origin - anterior surface of ribs 3-5 Insertion - coracoid process of scapula (visible from the front) Action - Moves the shoulder forwards Sport - Basketball & baseball Attaches arm to chest in front of body

Clavicular Head: Origin, insertion, action, location

Origin - medial half of inferior edge of clavicle Insertion - lateral edge of proximal humerus Action - moves humerus in upward motion Sport - bowling, volleyball bump (Pectoralis Major so breast muscles)

Sternal Head: Origin, insertion, action, location

Origin - ribs 1-5 on lateral edge of sternum Insertion - lateral edge of proximal humerus Action - arm adduction Sport - slapping, tennis forearm (Pectoralis Major so breast muscles)

Abdominal head: Origin, insertion, action, location

Origin - ribs 5-7 Insertion - lateral edge of most proximal part of humerus Action - moving arm in downward motion Sport - serving in tennis (Pectoralis Major so breast muscles)

Intercostals: Origin, insertion, action, location

Origin - vertebrate Insertion - sternum Action - expands the chest so lungs can fill with air Sport - swimming Between ribs

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?

This is an example of a muscle being classified based on its location in the body. This muscle is most likely on the front of the tibia (the larger bone on the lower leg also known as the shinbone).

Cardiac muscle: striations, voluntary, location, and function

straitons- yes voluntary- no location- heart function- contraction of atria and ventricles, cause circulates blood throughout body

Smooth muscle: striations, voluntary, location, and function

striation-no voluntary- no location- in lymphatic vessels, urinary bladder uterus function- push out baby, urine, flow of arteries, move food through digestive system

Skeletal muscle: striations, voluntary, location, and function

striations- yes voluntary- yes location- attaches to bone function- move body