Muscles Flashcards
arrangement of fascicles in muscles
circular convergent fusiform parallel pennate
circular arrangement of fascicles
fascicles are arranged in concentric rings
surround external body openings
sphincter - general name for circular muscle
examples:
-orbicularis oris around the mouth
-orbicularis oculi around eye orbit
convergent arrangement of fascicles
origin of the muscle is broad
fascicles converge toward the tendon of insertion
example: pectoralis major
fusiform arrangement of fascicles
fascicles run parallel to the long axis of the muscle and have an expanded central belly
eg biceps brachii
parallel arrangement of fascicles
fascicles run parallel to the long axis of the muscle
eg sartorius, sternocleidomastoid
pennate arrangement of fascicles
unipennate - fascicles insert into one side of the tendon (eg extensor digitorum longus)
bipennate - fascicles insert into the tendon from both sides (eg rectus femoris)
multipennate - fascicles insert into one large tendon from more than two sides (eg deltoid)
muscle groups based on location and function
non-cardiac visceral organ muscles, glands, and blood vessels: smooth muscle
cardiac muscle: cardiac muscle
head and neck muscles: skeletal muscle
axial/trunk muscles: skeletal muscles of thorax, abdomen, pelvis
limb muscles: skeletal muscles of upper and lower extremities
muscles of facial expression
face: orbicularis oculi, orbicularis oris
scalp: epicranius with frontal belly, occipital belly, and galea aponeurotica
neck: platysma
thin and variable in shape
often insert in skin, not on bones
innervated by the facial nerve
muscles of mastication
prime movers of jaw closure and biting: masseter and temporalis
side-to-side movement of jaw: pterygoid muscles
compression of cheeks: buccinator muscles for whistling, sucking (eg breast feeding)
innervated by mandibular division of the trigeminal nerve
tongue movement muscles
genioglossus: attached to mandible
hyoglossus: attached to hyoid bone and depresses tongue
styloglossus: attached to styloid processes
hypoglossal nerve
swallowing muscles
suprahyoid muscles: close larynx air passage with swallowing
digastric, mylohyoid, stylohyoid
pharyngeal constrictor muscles: squeeze food into esophagus
superior, middle, inferior
infrahyoid muscles: open larynx for breathing after swallowing
omohyoid, sternohyoid, thyrohyoid, sternothyroid
deep muscles of posterior back and neck
semispinalis
quadratus lumborum
erector spinae group - iliocostalis, longissimus, spinalis
functions of deep muscles of posterior back and neck
trunk extension and head movement
maintain normal curvatures of spines
muscles extend from sacrum to the skull
deep muscles of the thorax: intercostals for breathing
deep muscles provide movements for breathing
external intercostal muscles - superficial to internal
lift the rib cage
internal intercostal muscles -
aid expiration during heavy breathing
deep muscles of the thorax: diaphragm for breathing
most important muscle of respiration
flattens as it contracts, which increases the volume of the thoracic cavity