Lab 9 Flashcards
(28 cards)
What happened to the muscles pectoralis and trapezius in mammals?
a single muscle split into two discrete muscles that insert at different points
What are the most dramatic differences that distinguish muscles of mammals from other chordates? What does the complexity of these mammalian muscles allow?
cranial and appendicular musculature
allows them to be used in nursing, mastication, and communication (facial expression)
Compare muscles of mammals to amphibians.
- facial muscles of mammals are homologous to two muscles only in amphibians
- five mammalian branchiomeric muscles (masseter and temporalis) are homologous to the adductor mandibulae of amphibians
- mylohyoid and digastric of mammals are homologous to the intermandibularis of amphibians
- sternohyoid, omohyoid, thyrohyoideus are homologous to just one muscle in amphibians
- caudofemoralis, semitendinosus, biceps femoris, semimembranosus and gracilis are homologous to only two muscles of salamanders
What is different about the pectoral girdle of mammals compared to amphibians?
- pectoral girdle of mammals is not attached to the vertebral column
- it is suspended by a sling of muscles between the two scapulae which have spines for muscle attachment
Why is the pectoral girdle of mammals not attached to the vertebral column?
to absorb shock of the front limbs hitting the ground, reducing the jarring of the viscera and brain
What is the function of the cutaneous trunci? Where does it originate and insert?
moves the skin, originates from some of the shoulder muscles and inserts on the underside of the skin
What is the role of the cremasteric pouch?
contains the testes, blood vessels and sperm ducts
penis embedded within it
Since minks are part of the skunk family, what structure releases the foul smell?
musk glands (sacs on either side of anus, just ventral to the tail)
What is the platysma? Function?
a cutaneous muscle derived from the hyoid (neck) musculature that controls
facial muscles that control eyelids, lips, nose, pinnae
What two salivary glands are located close to the hyoid venous arch?
mandibular gland and parotid gland
What are the two components of the trapezius? What are their functions?
trapezius cervicis=protracts the shoulder
trapezius thoracis=retracts the shoulder
in general, where do dorsal muscles of the shoulder usually insert?
humerus
What are the two components of the extensor carpi?
radialis and ulnaris
Which is the largest thigh muscle?
biceps femoris
What is the fascia latae?
covers the lateral surface of the thigh, attached to the tensor fasciae latae
Which is the largest muscle along the caudolateral surface of the shank?
gastrocnemius-lateralis
High gear vs low gear muscles.
high gear=low force
low gear=high force
Which muscle is fan-shaped?
serratus ventralis
What is the relative size of temporalis and digastric in herbivores compared to carnivores?
temporalis is smaller in herbivores
digastric larger in herbivores
What are the two portions of triceps brachii?
longus and laterallis
True or false. Gluteus superficialis is larger in quadripeds.
True
What allows young mammals to nurse?
facial muscles
Match.
Scalenus, rectus thoracis, serratus ventralis, longus colli
retracts ribs, suspends pectoral girdle, flexor of neck, pulls ribs towards head
scalenus: pulls ribs towards the head
rectus thoracis: retracts ribs
serratus ventralis: suspends pectoral girdle
longus colli: flexor of neck
Which muscles insert on humerus?
teres major, subscapularis, scapuldeltoideus
