muscular system AP

What are the three types of muscle tissue

Skeletal, smooth, cardiac

What is the skeletal muscle tissue

• also called striated/ voluntary

• Long cylindrical fibers; multinucleated

• Under conscious control. Important in surgical positioning and access

What is smooth muscle

• found in hollow organs: intestines, blood vessels, uterus, bladder

• Involuntary; non-striated

• Arranged in longitudinal/ circular layers

What is cardiac muscle

• found only in the heart

• Striated and involuntary

• Controlled by the autonomic nervous system

• Contracts rhythmically (~75 bpm)

What is muscular fiber

A single skeletal muscle cell, very long compared to width

What is a fascicle

Groups of fibers that form whole muscles

What are the connective tissue layers

• endomysium: surrounds each fiber

• Perimysium: surrounds each fascicle

• Epimysium: surrounds entire muscle

• Fascia: strong outermost layer that holds sutures during closure

How do muscles work

• contract in response to nerve impulses from motor neurons

• Each neuron innervates multiple fibers (motor unit)

• At the neuromuscular junction, acetylcholine (ACh) is released

• ACh triggers an action potential, leading to contraction

• Calcium is released, activating actin and myosin to slide past each other

What is ATP

the energy molecule for muscle contraction

How is ATP made

Vía glycolysis, Krebs cycle, ETC, and phosphocreatine breakdown

What would happen if there was no oxygen in muscles

lactin acid builds up causing fatigue

What are muscle names based on

• action: flexor, extensor, adductor

• Shape: trapezius, deltoid

• Origin/insertion: sternocleidomastoid

• Location: frontalis, tibialis

• # of origins: biceps (2), triceps (3)

• Fiber direction: oblique, transverse

What are muscle actions

• flexors: bend a joint

• Extensors: straighten a joint

• Adductors: move limb toward midline

• Abductors: move limb away from midline

• Levators: raise a part

• Depressors: lower a part

• Rotators, supinators, pronators: rotate/ position limbs

What does the frontalis muscle do

Raises eyebrows

What does the rectus abdominus muscle do

Used in sit ups

What does the diaphragm muscle do

Primary breathing muscle

What does the gastrocnemius muscle do

Calf muscles

What does the flexor digitorum muscle do

Flexes fingers

What does the superior rectus muscle do

Raises the eye

What does the brachialis, biceps brachii, brachioradialis muscle do

Flex the forearm

What does the wrist extensors muscle do

Found for sally

What does the tensor fascia lata muscle do

Abducts thigh

What is atrophy

Muscle wasting from inactivity

What is Hypertrophy

Muscle enlargement from use

What is Tendonitis

Inflammation of a tendon

What is Contracture

Permanent muscle shortening

What is ALS

Progressive motor neuron disease( Lou Gehrigs)

What is Muscular dystrophy

Genetic weakening of muscles

What is Myasthenia gravis

Autoimmune neuromuscular disorder

What is Polio

Viral motor neuron damage

What is Fibromyalgia

Widespread muscle pain

What is Tetanus

Muscle spams from bacterial toxin