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Muscular System Belen Esparza Period: 2, image - Coggle Diagram
Muscular System
Belen Esparza
Period: 2
Muscle Coverings (Connective Tissue Coverings)
Perimysium
(
surround fascicles
) - Surrounding each fasclcles is a layer of dense CT called perimysium
Endomysium
(
surrounds each muscle fiber
) - Fine aerolar CT that surrounds each individual muscle fiber
Epimysium
(
outside the muscle
) - an overcoat of dense irregular CT that surrounds the whole muscle
Disorders Associated with the Muscular System
Myasthenia Gravis is a nueromuscular disorder that blocks neurotransmitters.
It is more common for
women
and those of
older
ages. While there is
no known cure
,
medication
can help the symptoms.
Cerebral Palsy is spastic paralysis that causes muscle weakness
.
Premature births
, a
brain injury/abnormality
, and
bleeding in the brain
are all risk factors and can result in cerebral palsy. Symptoms include but are not limited to
delayed development
and
seizures
. While there is
no cure
there is
medication for the symptoms
and surgical intervention.
1 in 278 children
are estimated to have cerebral palsy.
Fibromyalgia: Muscle pain
Myositis is the inflammation of the muscle
. Myositis is
autoimmune
, and can result from an
infection or muscle trauma
. The symtoms for myositis include but are not limited to
tenderness
and
swelling
, but some
medication
and
antibiotics
can be used as treatment.
Muscular Dystrophy is muscle weakness and atrophy
MD is
genetic
and the symptoms include
loss of strength, delayed motor skills
, and
mental retardation
. There is
no known cure
.
3 Types of Muscules + Functions
Skeletal Muscle
Skeletal Muscle Tissue
-
Appearance
: Big thick lines with striations, is what the skeletal muscle tissue looks like to me. The dark round circles being nuclei
Function
: Its role being voluntary movement of skeletal parts. Skeletal muscles move the head, trunk, and limbs
Location
: Skeletal MT makes up the muscles that attach to bones, so Skeletal MT is usually attached to bones**
Smooth Muscle
Smooth Muscle Tissue
-
Appearance
: Holing a similar appearance to that of a squamous cell we have squashed cell shape connected to layers upon layers of other smooth muscle cells and its nucleus in the center of the cell
Function
: Allows for involuntary movement of the internal organs
Location
: Located in the walls of internal organs.
Cardiac Muscle
Cardiac Muscle Tissue
-
Appearance
: Cardiac muscle cells are connected but also branch out from each other, and have both striations and intercalated disks. Their nuclei appears to be popping out
Function
: Its role being contraction for heartbeats
Location
: Located in the heart muscle
Action Potential in a Muscle Fiber
Action potential
- a neural impulse; a brief electrical charge that travels down an axon
Threshold
- The level of stimulation required to trigger a neural impulse
Refractory period
- in neural processing, a brief resting pause that occurs after a neuron has fired. New action potentials can not occur until axon returns to resting state
All-or-none response
- A neurons reaction of either firing or not
Sarcomere
Sarcomere
- segment of a myofibril
I bands ( thin filaments only)
- actin filaments with tropomyosin linings and trroponin attachments
A bands
(thick and thin filaments overlap
) - Overlapping thick/thin filament
H Zone (thick filaments only)
: Myosin filaments only, myosin includes myosin heads with actin binding sites
M Line (thick filaments linked by accessory proteins)
- Consists of proteins that hold myosin filaments in place
Z disc
: the anchoring to the sarcolemma
Neuromuscular Junction
1) Action potential arrives at axon terminal of motor neuron
2) Voltage gated Ca^2+ channels open. Ca2+ enters the axon terminal, mivung down its electromagnetic gradient.
3) Ca^2+ entry causes ACh to be released by exocytosis
4) ACh diffuces across the synaptic cleft and binds to ACh receptors on the sarcolemma
5) ACh binding opens chemically gated ion chanells that now allow simultanious passage of Na+ into the muscle fiber and K+ out of the muscle fiber. More Na+ fibers enter than K+ ions exit, which produces a local change in the membrane potential called the end plate potential.
6) ACh effects are terminated by its breakdown in synaptic cleft by acetylocholinesterase and diffusion away from the junction.
Major Functions of the Muscular System
Mobility
: The muscle's main function is to provide movement
Joint stability
: Muscle tendons stretch over joints and contribute to joint stability
Posture/body position
: Counter-react the downward pull of gravity, skeletal muscles do this
Generate heat
: Muscles generate heat when they contract, plays a large role in maintaining normal body temperature
Names of all the Skeletal Muscles
Anterior
Inferior view
Adductor longus:
Fibularis longus:
Extensor digitorum longus:
Gastrocnemius:
Iliotibial tract:
Rectus femoris
Sartorius:
Soleus:
Tibialis anterior: shinbone; dorsiflexion and inversion of foot
Vastus medialis: medial thigh; part of hamstrings
Gracilis:
Vastus lateralis:
Superior view
Orbicularis oculi
: around eyes; closes eye as in blinking
Iliopsoas:
Flexor carpi radialis
: flexes wrist and abducts hand
Masseter
: jaw; closes the jaw
Frontalis (Epicranius frontal belly):
Flexor carpi ulnaris:
External obliques
: sides of abdomen; laterally flexes and rotates vertebral column (superficial)
Deltoid
: shoulder blades; abduct, flex, extend and rotate the arm
Bicep brachii
: front of upper arm (superficial); flexes the forearm
Brachioradialis:
Brachialis
: front of arm (deep) flexes forearm
Orbicularis oris
: mouth; closes lips
Palmaris longus:
Pectinus:
Pectoralis major
: front upper chest; flexes, adducts, and rotates the shoulder medially
Pronator teres:
Rectus abdominis:
Serratus anterior
: along ribs; accessory respiratory muscle; raises ribcage
Sternocleidomastoid
: sides of neck; one side contraction: laterally flexes neck, rotates head to opposite side;
both sides together: flexes neck forward
Temporalis
: temples; closes jaw
Tensor fasciae latae
: along the quad; stabilizes trunk
Trapezius
: back of neck and upper back; extends or straightens neck + elevates the shoulders
Triceps brachii
: back of upper arm; extends forearm at elbow
Zygomaticus
: cheekbone and mouth; raises corner of mouth
Posterior
Superior view
Teres major:
Latissimus dorsi:
Occipitalis
(Epicranius occipital belly): back of skull; aids in extending head
Gluteus medius:
lateral surface of ilium: abducts and rotates thigh medially
Infraspinatus:
Extensor carpi radialis
: Extends wrist and abducts hand
Deltoid
: shoulder blades; abduct, flex, extend and rotate the arm
Brachioradialis : Thumbside elbow
Extensor carpi ulnaris:
Flexor carpi ulnaris:
Gluteus maximus
: buttocks; extends thigh and back at the waist
Rhomboid major:
Sternocleidomastoid:
Teres minor
: rotator cuff muscle, laterally rotates arm
Tricep brachii:
Inferior view
Bicep femoris
: lateral back of thigh; part of quadriceps
Adductor magnus:
Gastrocnemius
: back of leg (superficial); plantarflexes ankle
Gracilis
:
Soleus:
Fibularis longus
: lateral lower leg; plantarflexes foot
Semitendinosus
: medial back of thigh (superficial); part of quadriceps
Semimembranosus
: medial back of thigh (deep); part of quadriceps
Calcaneal
(Achilles) - tendon of the heel (not a muscle)
Sliding Filament Theory of Muscle Contraction
1) An impulse travels down a motor neuron axon.
2) The motor neuron releases the neurotransmitter
acetylcholine (ACh).
3) ACh binds to ACh receptors in the muscle fiber
membrane.
4) The sarcolemma is stimulated. An impulse travels over the surface of the muscle fiber and deep into the fiber
through the transverse tubules.
5) The impulse reaches the sarcoplasmic reticulum, and
calcium channels open.
6) Calcium ions diffuse from the sarcoplasmic reticulum
into the cytosol and bind to troponin molecules
7) Tropomyosin molecules move and expose specific sites on actin where myosin heads can bind.
8) Cross-bridges form, linking thin and thick filaments.
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