The Muscular System
Chapter 7
Muscle
• One of the 4 basic tissues of body
– Epithelial, connective, muscle,
nervous
• Made up of cells that can shorten
or contract
• Three different types of muscle
– ________________ muscle
Controlled by conscious mind and moves bones of skeleton.
– _________________ muscle
Found only in heart
– _________________ muscle
Found throughout body (intestines, lungs, blood vessels, etc..)
but controlled by unconscious mind
– All are either controlled or influenced
by the ____________ system
Basic Terminology
• ________- generally refers to muscle
– Myology, myositis
• ________- refers to muscles at the cellular level
– Sarcoplasm, sarcolemma
Skeletal
Muscle
• Moves the bones of the skeleton
• __________- can be controlled be
conscious mind
• __________- microscopically
visible striped pattern of alternating
light and dark bands that run the
length of a muscle cell.
Skeletal Muscle• The thick central portion is
called the ___________.
Gross Anatomy
• Muscles have two attachment
sites:
– _______________________- the end that
is generally more stable than the other.
Does not move when muscle contracts.
– _______________________- site that
undergoes most of the movement during
contraction.
• Most muscles attach to bone
via __________.
– Bands of dense regular connective tissue
made of _______fibers
APONEUROSIS: LINEA
ALBA
•Some muscles are unique because
they attach to bone or other muscles
by broad sheets of fibrous tissue
called______________________.
•The most prominent aponeurosis
is the ________ _________
•runs along an animal’s
ventral midline from sternum to
pubis.
•Connects abdominal muscles
from right and left sides
•Common site for abdominal
surgical incisions
Muscle Actions
• Skeletal muscles contract when stimulated to do so by a
nerve impulse.
• Muscles usually work in groups
– An _____________ or prime mover describes a muscle or
muscle group that directly produces a desired movement.
• __________________- a muscle that contracts at the same
time as a prime mover and assists it in carrying out action.
– An _______________ is a muscle or muscle group that
directly opposes the action of a prime mover.
– _____________- stabilizes joints to allow other movements
to take place.
Muscle Naming Conventions
• Muscles are generally named by physical
characteristics:
– Action
• Example: deep digital flexor
– Shape
• Example: deltoid muscle
– Location
• Example: biceps brachii
– Direction of Fibers
• Rectus abdominus- rectus means straight
– Number of heads or Divisions
• Example: triceps brachii
– Attachment sites
• Sternocephalicus- originates on sternum, inserts on head
• CUTANEOUS MUSCLES
– Muscle in the connective tissue
beneath the skin
– Little or no attachment to bone
– Thin, broad, and superficial
– Serves to twitch the skin
• Cutaneous trunci
• HEAD AND NECK MUSCLES
– HEAD: control facial expressions, enable chewing,
move sensory structures
• Masseter
– NECK: support head, allow neck to flex, extend, and
move head laterally
•
•
•
•
Splenius
Trapezius
Braciocephalicus
Sternocephalicus
• ABDOMINAL MUSCLES
– Support the abdominal organs
– Flex/arch the back
– Allow straining for defecation, urination, parturition,
vomiting, regurgitation
– Assist in respiration
– Arranged in layers from superficial to deep:
•
•
•
•
External abdominal oblique
Internal abdominal oblique
Rectus abdominis
Transversus abdominis
• Each side of 4 muscles comes together at linea alba
• THORACIC LIMB
MUSCLES
– Function in locomotion
• Shoulder region:
– Latissimus dorsi
– Pectorals
– Deltoid
• Arm:
– Brachialis
– Biceps brachii
– Triceps brachii
• PELVIC LIMB
MUSCLES
– Function in locomotion
• Thigh region:
– Gluteals
– Hamstrings:
» Biceps femoris
» Semimembranosus
» Semitendinosus
– Quadriceps femoris
• Leg
– Gastrocnemius
• MUSCLE OF
RESPIRATION
– Increase and decrease the
size of the thoracic cavity to
bring air into and out of the
lungs
– Inspiratory muscles:
• Diaphragm
• External intercostals
– Expiratory muscles:
• Internal intercostals