muscles Flashcards
What is the name of the contractile proteins?
actin and myosin
which filament is thin?
actin
Which filament is thick?
myosin
What is the name of the light and dark striations seen on muscle tissue under a microscope?
Sarcomeres
What molecules provide energy for muscle movement?
adenosine triphosphate
what is a motor unit?
a single nerve together with the muscle fibres it supplies
what is the name of the junction between the nerve fibre and the muscle?
neuromuscular junction
what chemical transmits nerve impulses across the neuromuscular junction?
acetyl choline
What is isometric contraction?
when tension is generated in the muscle, muscle tone is increased, but the muscle does not shorten
What is isotonic contraction?
the muscle moves or shortens
what is the term for a muscle growing larger due to excessive use?
hypertrophied
What is the term for a muscle shrinking due to lack of use?
atrophied
what is the name of the thick fleshy central part of the muscle?
the belly
what is an aponeurosis?
a flat sheet of muscle and tendon
what is a sphincter muscle?
muscles that form a ring and control the entrance or exist of a structure
what is a bursa?
a connective tissue sac lined with synovial membrane and filled with synovial fluid
where would you find a bursa?
between a bony prominence and a tendon, ligament or muscle
what is the function of a bursa?
to reduce friction between the associated structure and the bone
what is the name of a bursa that wraps around a tendon completely?
synovial or tendon sheath
what are intrinsic muscles?
muscles that lie completely within on region of the body. they act on the joints in that part only.
What are extrinsic muscles?
muscles that run from one part of the body to another and alter the position of the whole part (e.g limbs) in relation to the other.
Name the muscles of mastication
Digastricus
masseter
temporalis
medial and lateral pterygoids
what is the function of the digastricus?
opens the jaw
where is the Digastricus located?
on the caudoventral surface of the mandible
what is the origin point of the diagastricus?
the jugular process of the occipital bone
what is the insertion point of the diagastricus?
angle and ventral surface of the mandible
what is the function of the masseter?
closes the jaw
Where is the masseter located?
lateral to the mandible
where is the origin point of the masseter?
the zygomatic arch
where is the insertion point of the masseter?
masseteric fossa on the lateral surface of the mandible
What is the function of the temporalis?
closes the jaw
What is the strongest muscle of the head?
the temporalis
where is the temporalis located?
covering much of the coral and lateral surfaces of the skull
what is the origin point of the temporalis?
the temporal fossa
what is the insertion point of the temporalis?
the coronoid process of the mandible
where are the medial and lateral pterygoids located?
medial to the mandible
what is the function of the medial and lateral pterygoids?
aid the temporalis and masseter in closing the jaw but also responsible for the side to side movements of the mouth
What are the extra ocular muscles responsible for moving the eye within its socket called?
the four rectus muscles
what is the function of the oblique muscles in the eye?
rotate the eye about its visual axis
What is the retractor bulbi?
a muscular cone around the optic nerve at the back of the eye
what is the action of the retractor bulbi?
to pull the eye deeper into the socket
Epaxial muscles
lie dorsal to the transverse process of the vertebrae
what is the function of the epaxial muscles?
to support the spine and allow lateral flexion
Hypaxial muscles
lie ventral to the transverse process of the vertebrae, one region associated with the neck, another with the back
what is the function of the hypaxial muscles?
flex the neck and tail, and contribute to flexion of the vertebral column
What is the origin and insertion point of the external intercostal muscles?
origination from the caudal boarder of one rib and inserting onto the cranial boarder of the rib behind it
What is the function of the external intercostal muscles?
assist in inspiration
Where are the internal intercostal muscles?
below the external intercostal muscles
what is the origin and insertion point of the internal intercostal muscles?
originate from the cranial surface of one rib and insert on the caudal border of the rib in front of it
What is the function of the internal intercostal muscles?
assist in expiration
What is the diaphragm?
the sheet of muscle that separates the thoracic and abdominal cavities
What are the parts of the diaphragm?
the central tendon and muscular periphery
Where does the diaphragm arise from
the lumbar vertebrae, caudal ribs and sternum
What is the name of the lumbar portion of the diaphragm that consists of thickened muscular bundles?
right and left crura (crus)
What are the three openings in the diaphragm that allow structures through into the abdomen?
aortic hiatus
oesophageal hiatus
caval foramen
What structures pass through the aortic hiatus?
the aorta,
azygous vein
thoracic duct
What structures pass through the oesophageal hiatus?
the oesophagus
vagal nerve trunks
what structures pass through the caval foramen?
the caudal vena cava
what are the names of the abdominal muscles?
External abdominal oblique
internal abdominal oblique
transverse abdominal oblique
rectus abdominis
Where does the external abdominal oblique originate and insert?
originates from the lateral surfaces of the ribs and lumbar facia and terminates in the midline linea alba
What is the internal abdominal oblique?
intermediate muscle of the lateral abdominal wall, terminates in the linea alba
What is the transverse abdominal oblique?
the deepest of the lateral abdominal muscles, terminates in the linea alba
What is the external abdominal oblique?
most superficial lateral abdominal muscle
What is the rectus abdominis?
a broad band of muscle on each side of the linea alba that forms the floor of the abdomen,
What is the origin and insertion points of the rectus abdominis?
originates on the first rib and sternum and inserts on the pubis
what tendon allows the rectus abdominis to insert onto the pubis?
the prepubic tendon
What is the linea alba?
the combined aponeuroses of the three lateral abdominal muscles.
Where is the linea alba?
extends along the ventral midline from the xiphoid process to the sternum to the pubic symphysis
what is the inguinal ring?
a slit-like opening in the aponeurosis of the external abdominal oblique in the region of the groin
what is the function of the inguinal ring?
allows the passage of blood vessels from the abdomen to the external genitalia and mammary glands, and transmits the structures of the spermatic chord to the scrotum
What are the extrinsic muscles of the forelimb?
trapezius
pectoral
latissimus dorsi
brachiocephalicus
What is the origin and insertion point of the trapezius?
origin the dorsal midline from C2 to C7 inserts on the spine of the scapula
What is the function of the trapezius?
draws the leg forward and protracts the limb
What is the origin and insertion point of the pectoral muscles?
runs from the ribs and sternum and inserts on the humerus
What is the action of the pectoral muscles?
adduct the limb and hold the forelimb against the body wall
What is the origin and insertion point of the latissimus dorsi?
broad origin on the thoracic spine and inserts on the humerus
what is the function of the latissimus dorsi?
retracts the forelimb
What is the origin and insertion point of the brachiocephalicus?
runs from the base of the skull to an insertion point on the cranial aspect of the humerus
what is the function of the brachiocephalicus?
when the limb is on the ground it flexes the neck and bends the neck laterally; when the limb is not taking weight it draws the foreleg forward and protracts the limb
what are the intrinsic muscles of the forelimb?
supraspinatus infraspinatus triceps brachii biceps brachii brachialis
What is the origin and insertion point of the supraspinatus?
originates from the suprapinous fossa inserts onto the greater tubercle of the humerus
What is the action of the Supraspinatus?
Extends the shoulder and stabilises the shoulder joint
What is the origin and insertion point of the Infraspinatus ?
Originates from the infraspinous fossa of the scapula and inserts on the greater tubercle of the humerus
What is the action of the Infraspinatus?
Helps to stabilise the shoulder joint and flexes the shoulder joint
What is the origin of 3 of the heads of the triceps brachii muscle?
proximal humerus
what is the origin of the fourth head of the triceps brachii muscle?
the scapula
Where do the muscles of the triceps brachii insert?
the olecranon of the ulna
what is the action of the triceps brachii?
extends the elbow joint
what is the origin and insertion point go the biceps brachii?
originates from the supraglenoid tubercle of the scapula and inserts on the radius and ulna
what is the action of the biceps brachii?
flexes the elbow joint
what is the origin and insertion points of the brachialis muscle?
originates from the humerus and inserts onto the radius and ulna
what is the action of the brachialis muscle?
flexes the elbow joint
What are the main muscles of the carpus and digits?
two carpal extensors
two digital extensors
two carpal flexors
two digital flexors
Where do the carpal extensors originate and insert?
originate from the humerus and inset on the carpals
where do the carpal extensors run?
in front of the lower limb and foot
where do the digital extensors originate and insert?
originate from the humerus and insert on the third phalanx
where do the digital extensors run?
in front of the lower limb and foot
where do the carpal flexors run?
behind the carpus and foot
what makes up the two digital flexors?
the superficial digital flexor
the deep digital flexor
where does the superficial flexor insert?
the second phalanx
where does the deep digital flexor insert?
the third phalanx
what are the extrinsic muscles attached to the vertebral column and the pelvic girdle?
the sublumbar hypaxial muscles
What are the muscles of the gluteals?
the superficial gluteals
the middle gluteals
deep gluteals
tensor fascia latae
what is the action of the gluteals?
extend the hip joint and abduct the thigh
what muscles make up the hamstring group?
biceps femoris
semitendinosus
semimembranosus
what is the action of the hamstring group of muscles?
to propel and extend the whole limb backwards
what is the position of the biceps femoris?
the most lateral hamstring muscle, originates from the pelvis and runs over the femur to the tibia and inserts on the calcaneus of the hock
what is the action of the biceps femoris?
extends the hip, flexes the stifle and extends the hock
what is the position of the semitendinosus?
runs from the pelvis and inserts on the tibia and calcaneus
what is the action of the semitendinosus?
extends the hip, flexes the stifle and extends the hock
what is the position of the semimembranosus?
the most medial hamstring muscle, runs from the pelvis to the femur and tibia
what is the action of the smeimembranosus?
extends the hip and flexes the stifle
What is the position of the quadriceps femoris?
runs down the cranial aspect of the thigh, consists of 4 parts that all insert on the tibial tuberosity or crest.
what is the action of the quadriceps femoris?
extends the stifle joint
what muscles make up the adductor group?
pectineus
sartorius
gracilis
what is the position of the pectineus?
runs from the pubis to the distal femur
what is the action of the pectineus?
adducts the limb
What is the position of the sartorius?
inserts on the cranial border of the tibia with the gracilis muscle
what is the action of the sartorius?
adducts the limb
What is the position of the gracilis?
forms the caudal half of the medial surface of the thigh
what is the action of the gracilis?
adducts the limb
what is the position of the Gastrocnemius muscle?
originates from the caudal aspect of the femur and inserts on the calcaneus of the hock
what is the action of the Gastrocnemius?
extends the hock and flexes the stifle
Which opening lies within the central tendon of the diaphragm?
Caval foramen