Muscular System Flashcards
What are the 3 types of muscle tissue?
Skeletal, smooth, and cardiac
What are skeletal muscles attached to?
bones
Describe a skeletal muscle.
long, narrow with many nuclei and dark striations
Skeletal muscles are arranged in bundles called ________
Fascicles that are then grouped together as muscles. The muscles have a covering of dense connective tissue called fascia that continues as a tendon
What are tendons?
Tendons attach muscles to bones
Where is smooth muscle located?
In the walls of hollow organs and blood vessels
What are the characteristics of smooth muscle fiber?
Smooth muscles have one nucleus, no striations, and short, narrow fibres that are arranged in sheets or layers
Which muscles tissue type is the ONLY voluntary control?
Skeletal
Where is cardiac muscle located?
The heart
What are the characteristics of the cardiac muscle fiber?
Cardiac muscle tissue has one nucleus, striations and is rectangular in shape. They are arranged in branching networks.
What are the functions of muscle tissue?
Movement Stability or muscle tone Control of body openings and passages Communication Heat production
What are the two attachment sites for skeletal muscles?
The origin: is anchored (via tendons) at one end to an immovable bone or structure
The insertion: is anchored at the other end to a moveable bone or structure
What is a synergist?
Muscles that have the same action
What is a prime mover?
Main muscle of the synergists that performs the action
What is an antagonist?
Muscle that has an opposing action
What is flexion and extension?
flexion- bending
extension- straightening
*hyperextension- excess extension beyond the anatomical position
What is abduction and adduction?
abduction: moving a part AWAY from the midline
adduction: moving a part TOWARDS the midline
What is inversion and eversion?
inversion: moving the soles medially so they face inward
eversion: moving the soles laterally so they face outward
What is dorsiflexion and plantar flexion?
dorsiflexion: bending the foot upward
plantar flexion: bending the foot downward
What is supination and pronation?
supination: turning the palm upward
pronation: turning the palm downward
What is circumduction and rotation?
circumduction: moving a distal end of a part in a circular path
rotation: moving a part around an axis
What are the muscles of facial expression?
Frontalis: covers the frontal bone (raise eyebrows)
Occipitals: covers the occipital bone (raise eyebrows)
Orbicularis occuli: surrounds the eye (closes eye)
Orbicularis oris: surrounds the mouth (closes and protrudes lips)
Zygomaticus: Extends between corner of mouth and zygomatic bone (raises corner of mouth to smile)
What are the muscles of mastication?
Masseter: covers the jaw (elevates mandible)
Temporalis: covers the temporal bone (elevates mandible)
What muscles flex and extend the head?
Sternocleidomastoid: together flex the head and individually they rotate the head
Trapezius: extends the head
What are the muscles that move the shoulders?
- Trapezius: upper back (elevates shoulders)
- Deltoid: covers tip of shoulder (abducts shoulder)
- Pectoralis major: chest (adducts shoulder)
- Latissimus dorsi: lateral back (adducts shoulder)
- Rotator cuff: tendons of the rotator cuff surround the shoulder in a circular fashion (rotates shoulder)
What are the muscles that move the elbow, wrist, and fingers?
- Biceps brachii: anterior upper arm (flexes the elbow)
- Triceps brachii: posterior upper arm (extends the elbow)
- Flexors: anterior forearm and palm of hand (flexes wrists and fingers)
- Extensors: posterior forearm and back of hand (extends wrist and fingers)
What are the muscles of respiration?
- Diaphragm: below the lungs (descends to enlarge the thoracic cavity during inspiration)
- External intercostals: between the ribs (elevate ribs to enlarge the thoracic cavity during inspiration)
What are the abdominal muscles that move the vertebral column?
- Rectus absdominis: anterior abdomen (flexes the vertebral column its the prime mover)
- External oblique: most superficial abdominal muscle on the lateral abdominal wall
- Internal oblique
- Transversus abdominis: deepest abdominal muscle
- These three aid the rectus abdomens in flexing the vertebral column
What is the erector spinae?
A muscle that extends the vertebral column, maintains vertebral column in erect position. It is located along the sides of the vertebral column
What is the function of the gluteus maximus and gluteus medius?
Gluteus maximus: extends the hip and laterally rotates the hip. Its location is the buttocks.
Gluteus medius: abducts the hip and medially rotates the hip. Its location is the internal buttocks
What is the function and location of the hamstrings?
The hamstrings extend the hip and are located on the posterior thigh
What make up the iliopsoas?
The psoas major: flexes the hip (prime mover with the iliacus) and is located inside the pelvic cavity
Iliacus: flexes the hip (prime mover with the psoas major) and is located inside the pelvic cavity
What is the location and function of the rectus femoris?
The rectus femoris flexes the hip and is located on the anterior thigh
What is the location and functions of the adductors?
Adduct the hip and are located on the medial aspect of the thigh
What are the muscles that move the knee and ankle?
- Quadriceps femoris: extends the knee and is located on the anterior thigh
- Hamstrings: flexes the knee and is located on the posterior thigh
- Gastrocnemius: flexes knee and plantar flexion of the ankle and is located on the posterior lower leg
- Tibialis anterior: dorsi flexion of the ankle and is located on the anterior lower leg
What are muscle fibers?
Muscles fibres are multinucleate single cells that extend the full length of a muscle
What are fascicles?
Bundles of muscle fibers
What is sarcolemma?
Cell membrane that surrounds each muscle fiber
What is the function of the mitochondria, sarcoplasmic reticulum and myoglobin in each finer?
Mitochondria: provides skeletal muscles with energy
Sarcoplasmic Reticulum: stores calcium
Myoglobin: store oxygen temporarily in muscle fibers that decrease the need for a continuous blood supply
What are myofibrils?
Myofibrils are contractile structures of a muscle fiber and consist of two types of protein filaments
- thin myofilaments called actin
- thick myofilaments called myosin
What is the organization of a skeletal muscle beginning with the smallest structures?
myofilaments, myofibrils, muscle fibers, fascicles, muscle
Which part of the brain coordinates skeletal muscle movement?
The cerebellum
What is the neuromuscular junction?
The end of a motor neuron and the motor end plate of a muscle fiber
What is the synaptic cleft?
The gap between the motor neuron and the muscle fiber
What is acetylcholine?
A neurotransmitter that is released from the synaptic vesicles. The acetylcholine crossed the synaptic cleft and attaches to the receptors on the muscle fibres causing the muscle fiber to be stimulated
What does stimulation of the muscle fiber cause?
- Causes calcium ions to leave the sarcoplasmic reticulum and bathe the actin and myosin myofilaments
- The increased calcium levels allow myosin to bind to actin
- Once bound myosin pulls on actin causing the myofilaments to slide along one another thus causing the muscle fiber to contract
- An enzyme acetylcholinesterase is present on the surface of the muscle fiber and it decomposes the acetylcholine thus preventing a single nerve impulse from causing continued stimulation of the muscle fiber
Explain the physiology of muscle contraction.
- Impulse initiates from the cerebrum
- Impulse coordinated by cerebellum
- Impulse travels down motor neuron towards neuromuscular junction
- Acetylcholine released into synaptic cleft stimulating muscle fibres
- Calcium ions diffuse out of the sarcoplasmic reticulum
- High calcium ion levels create active sites on the actin filaments- myosin able to attachh- actin filaments shorten and muscle contracts
- Acetylcholinesterase breaks down acetylcholine and muscle fibers no longed stimulated
- Calcium ions diffuse back into sarcoplasmic reticulum
- Actin-myosin links broken and filaments slide apart
- Muslce relaxes
What is the difference of aerobic respiration and anaerobic respiration?
aerobic respiration: occurs in the presence of sufficient oxygen, glucose is converted to pyruvic acid and then broken down efficiently to produce a large amount of energy
anaerobic respiration: occurs in the absence of sufficient oxygen, glucose is converted to pyruvic acid but then only a small amount of energy is produced along with the by-product lactic acid
What is ATP?
ATP (adenosine triphosphate) is the usable form of energy created by either aerobic or anaerobic respiration.
*If ATP is not immediately required by the cell it will store the ATP as creatine phosphate
What is oxygen debt?
The amount of additional oxygen that liver cells require to convert the accumulated lactic acid formed from anaerobic respiration back in to glucose
What is muscle fatigue?
The inability of a muscle to contract forcefully, accumulation of lactic acid is one of the factors responsible for muscle fatigue
