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Muscular System Belinda Santiago Period 2, Names of all the skeletal and…
Muscular System Belinda Santiago Period 2
Muscle coverings (cnnctv tsu covering)
epimysium
dense irregular tissue surrounding entire mscl
endomysium
individual mscle fibrs, sheaths frm external to internal
contains the vessels and nerves that supply the muscle fibres
perimysium
fibrous connective tissue surrounding a bundle of mscl fibrs
Neuromuscular junction
Events
AP arrives at axon terminal
Voltage-gated calcium channels open, calcium enters motor neuron
Calcium entry causes release of ACh neurotransmitter into synpatic cleft
ACh diffuses across to ACh receptors (𝑁𝑎+ chemical gates) on sarcolemma
ACh binding to receptors, opens gates, allowing 𝑁𝑎+ to enter resulting in end plate
potential
Acetylcholinesterase degrades ACh
3 types of muscles and their functions
skeletal
maintains posture, stabilizes joints, and generates heat
smooth
maintains blood pressure and flow
cardiac
pumps blood (contracts)
Disorders associated w the muscular system
Muscle cramps
sudden, involuntary contraction of a muscle; bc of fatigue fractures, dehydration, or lack of nutrients
muscle fatigue
Inability of mscl 2 maintain strength of contraction or tension despite continued stimulation; related to lack of oxygen, lack of glycogen, and/or lactic acid buildup; lack of ATP is rarely a reason for fatigue, except in severely stressed muscles
Muscular dystrophy
a hereditary condition marked by progressive weakening and wasting of the muscles
Myasthenia gravis
a chronic autoimmune, neuromuscular disease that causes weakness in the skeletal muscles that worsens after periods of activity
Myopathy
neuromuscular disorders in which the primary symptom is muscle weakness due to dysfunction of muscle fiber
Myositis
group of rare conditions; weak, painful or aching muscles; gets worse, slowly over time
Sarcomere
smallest contractile unit of mscl fibr
A band and 1/2 of I band (like box cars of a train)
responsible for muscular contraction.
composed of thin actin and thick myosin filaments
Major functions of the muscular system
producing movement
maintaining posture
stabilizing joints
generating heat
Action potential in a muscle fiber
travels across the sarcolemma and also down the T tubules
triggers a sequence of actions that ultimately results in the contraction and relaxation of the muscle fiber which is called the excitation–contraction–relaxation cycle
Sliding filament theory of muscle contraction
during contraction, thin filaments slide past thick filaments, causing actin and myosin to overlap more, using cross bridges
Names of all the skeletal and facial muscles on the list given
frontalis, orbicularis oculi, temporalis, masseter, buccinator, obicularis oris, zygomarticus
serratus anterior muscle
triceps brachii
rhomboid major, latissimus dorsi, erector spinae
gluteus medius and gluteus maximus
biceps brachii, brachioradialis
gracilis, sartorius mscl
tibialis anterior
flexor carpi radialis, extensor carpi radialis, wrist extensors, extensor digitorum, flexor digitorum superficialis
levator scapulae
gastrocnemius and soleus
pectoralis major, four abdominal muscles: rectus abdominis, external obliques, internal obliques, transverse abdominis
quadracep: rectus femoris, vastas medialis, vastas latralis
hamstring: bicep femoris, semitendinosis, semimembranosis
extensor digitorum longus
platysma, sternocleidomastoid, deltoid, trapezius