Module 3 Flashcards
What are the three types of muscles?
Cardiac
Smooth
Skeletal
What are the components of all muscles?
- muscle tissue
- blood vessels
- tendons
- nerves
characteristics of smooth muscle
- controlled by the nervous system or hormones
- either generally inactive, only responding stimuli OR is rhythmic
characteristics of skeletal muscle
- help body move
- most is attached to bones via tendons
characteristics of cardiac tissue
- found in the heart
- contracts rhythmically, modulated by neural activity/hormones
what are the two characterizations of muscle?
morphological and functional
what are the two different morphological characterizations of muscle
smooth and striated
SMOOTH MUSCLE
- fusi form shaped cells with no striations
- centrally located nucleus within the cell
- found in blood vessels, digestive system, other viscera
STRIATED MUSCLE
- marked by both light and dark bands in appearance
- skeletal and cardiac
makeup of skeletal muscle
- long muscle fibres
- multi-nucleated cells
- peripherally located nucleus within the cell
makeup of cardiac muscle
- intercalated discs
- centrally located nucleus within the cell
what are the two functional characteristics of muscle?
voluntary and involuntary
VOLUNTARY MUSCLE
- consciously controlled in order to perform a specific function
- SKELETAL MUSCLE only
Which muscles are voluntary and which are involuntary?
VOLUNTARY = skeletal INVOLUNTARY = smooth, cardiac
what are the two muscle functions?
excitability and contractility
what is excitability?
muscle tissue recieves electrical signals from nerves or stimulation from hormones to contract
what is contrctility
when a muscle cell is activated by a nerve or stimulated by a hormone, this causes the muscle to shorten, resulting in a contraction
how many named muscles are apart of the skeletal muscle system
700
how much of a person’s weight is accounted for my skeletal muscle?
50%
functions of skeletal muscle?
- movement
- posture
- stabilize joints
- control excretion and swallowing
- produce heat
how are connective tissue and muscle tissue combined in skeletal muscle tissue?
the connective tissue surrounds the muscle tissue and attaches the ends of each muscle to bone
what are the three layers of connective tissue that are apart of skeletal muscle?
Epimysium
Perimysium
Endomysium
what is epimysium
layer of connective tissue that surrounds the entire muscle
what is permysium?
layer of connective tissue surrounding a bundle of muscle fibres (fascicle) within a muscle
What is Endomysium?
The layer of connective tissue that surrounds individual muscle cells (muscle fibre) within a muscle bundle
Six elements of a muscle cell
1) sarcolemma
2) nuclei
3) myofibril
4) myofilaments
5) sarcoplasmic reticulum
6) T-Tubules
SARCOLEMMA
- cell membrane surrounding muscle cell
- different than endomysium
- beneath the sarcolemma are the nuclei, myofibrils, and the sarcoplasm (cellular fluid)
NUCLEI
- skeletal muscle cells are multinucleated, meaning they have more than one nucleus
- these nuclei are located towards the outside of the myofiber
MYOFIBRIL
- structural units of the muscle cell
- contain contractile myofilaments
MYOFILAMENTS
- contractile units of the muscle cell
SARCOPLASMIC RETICULUM
- surrounds each myofibril
- where the muscle stores calcium
T-TUBULES
extensions of the sarcolemma that surround the myofibrils and transmit nerve stimulation to the sarcoplasmic reticulum within the cell
Structual makeup of myofilaments
- myofilaments are organized into repeated structural units known as SARCOMERES
- when shortened, sarcomeres cause contraction of the muscle
- each unit consists of ACTIN (thin) and MYOSIN (thick)
what is sarcomere banding?
skeletal muscle has a striated appearance due to the arrangement of actin and myosin into organized sarcomeres that form distinct lines and bands
what are the four different sarcomere bands
A BAND
Z LINE
M LINE
I BAND
which is darker, A band or I band?
A BAND
What are each of the Bands composed of?
A BAND = thick and thin filaments
Z LINE = protein that makes “zig zag” line marking beginning and end of each sarcomere
M LINE = composed of protein down the center of the sarcomere
I BAND = thin filaments, transverses two sarcomeres
the process of muscle contraction
the actin and myosin filaments slide over each other, which shortens the sarcomere
the four muscles involved in facial expression
- frontalis
- orbicularis oculi
- zygomaticus
- orbicularis oris
what is the frontalis
the muscle that covers the frontal bone and lifts the eyebrows, causing forehead to wrinkle
what is the orbicularis oculi
muscle surrounding the eye that forcefully closes teh eye when contracted
what is the zygomaticus?
extends from the zygomatic arch to the corners of the mouth. makes you SMILE
what is the orbicularis oris?
surrounds the mouth, enable puckering of the lips
what is mastication?
chewing
what are the two muscles involved with mastication
- temporalis
2. masseter
what is the temporalis?
extends from the temporal fossa of the parietal bone to the coronoid process
what is the masseter
extends from the zygomatic arch to the angle of the jaw. protracts the jaw (forward/backward movement)
which muscle is responsible for extending the neck and turning the face slightly to the opposite side?
semispinalis capitis
what are the two posterior muscles in the head and neck?
- semispinalis capitis
2. splenius capitis
what is the sternocleidomastoid?
flexes the neck and rotates the head with bilateral and unilateral contraction, respectively
EXTERNAL THORAX
external intercostals are the most superficial, their fibres run anteriorly and inferiorly between the ribs. AID IN INSPIRATION
INTERNAL THORAX
lie deep to the externals, fibres run superiorly and anteriorly. AID IN EXPIRATION.
what muscle group helps to keep the spine erect? Where can they be found?
erector spinae. RUn down both sides of the spinal column
EXTERNAL OBLIQUE
most superficial of the lateral abdominal wall musculature. Fibred run anteriorly and inferiorly
functions of the external oblique
bilateral - flexes the vertebral column and compresses the abdominal wall. USED IN FORCED EXPIRATION
unilateral - lateral flexion and rotation of the vertebral column
INTERNAL OBLIQUE
lies deep to the external oblique, fibres run anteriorly and superiorly
functions of the internal oblique
bilateral - flexes the vertebral column and compresses the abdominal wall.
unilateral - lateral flexion and rotation of the vertebral column
what is the transverse abdominus
runs horizontally, seep to the internal oblique
Functions of the transverse abdominus
bilateral - flexes the vertebral column and compresses the abdominal wall. USED IN FORCED EXPIRATION
unilateral - lateral flexion of the vertebral column
RECTUS ABDOMINUS
lies on either side of the linea alba (a line of connective tissue down the middle of the abdomen for muscle attachment) and is separated by tendinous intersections
(8 PACK)
functions of rectus abdominus
flexion of trunk, forced expiration
