5b: skeletal muscle Flashcards
The muscular system is divided into what 4 regions
- cranial (head) 2. Axial (associated with the sc) 3. thorax/lumbar/pelvic 4. fore and hind limbs
Cranial muscles: Do the arrangement of these muscles differ in marine mammals compared to those of terrestrial animals? Why?
yes, i.e.: making facial movements such as breathing, visio, eating, sound etc..
What are the facial muscles of marine mammals involved in?
opening/closing the nares/blow holes to prevent water from entering the lungs
Where are the facial muscles in sirenians and what is its function?
inserted into the snout (nose) which makes it very flexible and allows them to use their snout for manipulation of their food.
Where are the facial muscles in cetaceans and what is its function?
arranged and positioned around the air sac system on their foreheads which are involved with the production of sound
Facial muscles: mysticetes how are they arranged and was is their function/purpose?
facial muscles extend between the 2 halves of the mandible (jaw bone) which is used to squeeze ingested water throw the baleen that enters the mouth as they feed.
Which muscle in terrestrial animals allows the young to suckle on mothers nipples? how does it do this?
Buccinator muscle forms part of the cheek wall and gives them rigidity when suction is produced.
Cranial muscles: Cetaceans does the same suckling apply to these animals?
NO, they have long snouts therefore cannot suckle.
Cranial muscles: cetaceans how do they nurse their young?
the mother cetacean will squirt milk into the baby’s moth by contraction of special muscles over mammary glands.
Cranial muscles: Pinnipeds Explain masticatory muscles
similar to those found in terrestrial carnivores
Cranial muscles: Sirenians Explain masticatory muscles
similar to terrestrial herbivores
Cranial muscles: Cetacean Temporal muscle size and function
reduced temporal muscles (open and closes jaws in terrestrials)
Cranial muscles: Cetaceans What other 2 muscles are involved opening and closing the jaw? what do these muscles normally do?
pterygoids and masseter - normal: later movement (side to side)
Cranial muscles: tongue is made mostly of _____ muscle?
skeletal
Cranial muscles: describe the size of the blue whale tongue and the percent of body weight it makes up
tongue = size of an elephant = 2.5% of body weight
Where are axil muscles usually attached?
found attached to the Sc the entire length of the body
skeletal muscle: pinnipeds describe the neck length and purpose of neck muscles
very long and very muscular and function is balancing during movement. Males: used to deliver blows during fighting for territory during breeding
skeletal muscle: cetaceans describe the neck length and purpose of neck muscles
neck muscles are unremarkable (short necks)
Skeletal muscle: cetaceans what are the main muscles that create propulsion?
epaxial and hypaxial
skeletal muscle: cetaceans
draw and label the cross section lumbar region
Skeletal muscle: cetacean1. What are the two epaxial muscles?2. Where do each of these attach to?
- longissimus and multifidus 2. run along the dorsal side of the transverse processes of the vertebrae
What happens when spatial muscles contract?
they cause dorsal concavity or downward movement of the backpulls the tail up! ** do not affect head position
Explain what longissimus muscle does and where it attaches
exerts its powerful movements by being attached to the subdermal sheath of tendons that is attached onto the spinous and traverse processes along the back in cetaceans. attachment of the terminal tail vertebrae to this same subnormal sheet moves the tail fluke
Explain what multifidius muscle does and where it attaches?
Attaches to the posterior thoracic and lumbar vertebraefn: stiffen the back which provides stable platform of origin for the longissimus muscle
Where is the cutaneous trunci muscle located??
muscle covers most of the thorax and abdomen in many mammals
What is the function and purpose of cuteanous trunci muscle in sirenians?
very large and addicts in the downstroke of the tail
What is the function and purpose of cuteanous trunci muscle in cetaceans?
specialized and overlies the mammary gland which it compress to squirt into the mouth of nursing young.
Explain what the large hypaxial lumborum muscle does in cetaceans?
powers the downstroke of the flukestart attaching toe ventral side thoracic and lumbar vertebraeend: attaching to the ventral side of the caudal vertebrae and chevrons.
What are the two extensions of hypaxials lumborum?
- flexor caudae lateralis2. medialis
1./2.What is the purpose of retractor penis muscles found in cetaceans? (2)3.Is is not under ____ control like foudn in terrestrial mammals?
- retracts from pouch in body.2. helps maintain curve of penis and possible act as breaking during erection 3. muscular control
fore limb muscles: cetaceansWhat are the roles of the limbs?
involved with steering and NOT propulsive forces during swimming
fore limb muscles: cetaceansDescribe the shoulder movement
shoulder movement is mainly adductive (bring inward) and addictive (move outward) flexion and extension are limited.
fore limb muscles: cetaceanswhat do they not have ? and what is the consequence of that?
no clavicle mainly muscles actor the scapula to the thoraxsuch as: pectorals, rhomboids, serrated ventralis, and latissimus
What is the type of joint between scapula and humerus in cetaceans?
ball and socket joint movement
What allows for some mobility between elbow, wrist and fingers?
ligaments
fore limb muscles: sirenians what are the role of these limb?describe type of joints
- forelimbs are NOT used for propulsion; used to manipulate food and have muscles as those of territorial mammals2. synovial joints at the shoulder, elbow and wrist
fore limb muscles: PinnipedsWhat is the role of the clavicle
ALL seals do not have clavicle; shoulder is loosely attached too the chest
fore limb muscles: pinnipeds (phocidae)1. what are their forelimbs used for?2. flexibility of wrist and hand and extensivement of the muscular
- forelimbs not used for propulsion during swimming or have little role for land locomotion (expect northern seals for grabbing ice) 2. forearm/hand is very mobile
fore limb muscles: pinnipeds (Otariidae)1. what are their forelimbs used for?2. flexibility of wrist and hand and extensivement of the muscular
- provide much of the propulsive force when swimming and used as locomotion on land2. flipper lack extensive muscles; reduced mobility in wrists
fore limb muscles: pinnipeds (odobenidae)1. what are their forelimbs used for?2. flexibility of wrist and hand and extensivement of the muscular
- do no provide propulsive force when swimming but are used for locomotion on land2. mobile forearm and wrists
Hind lime muscles: cetaceansdescribe what changes have occurred compared to terrestrials?
no hind lumps muscles in modern cetaceansrudimentary pelvis parts that sometimes can be found; seem to function as an attachment pt of the retractor penis muscle
Hind limb muscles: pinnipedsHow develop are they?
very well developed
Hind limb muscles: pinnipedswhich suborder uses their hindlimb for movement on land?
odobenidae and ottariids
Hind limb muscles: pinnipedsWhat do phocidae and odobenidae use their limbs as?
use their limbs in adduction/abduction movement with their feet inverted
Hind limb muscles: pinnipedswhat muscle is present in all pinnipeds but when cross is much stronger in provides than otariids?
muscles below the knees
Hind limb muscles: pinnipedswhich suborder does not use their hindlimb when cwomming but use them for locomotion on land?
Otariidae
