Human Anatomy Ch. 6 Flashcards

Questions and Answers

Name and describe the three different layers of connective tissue in a muscle.

Endomysium - encloses a single muscle fiber. 2) Perimysium - wraps around a fascicle (bundle) of muscle fibers. 3) Epimysium - covers the entire skeletal muscle.

Myofibrils are composed primarily of two protein filaments called and _.

Myosin and actin.

What is a motor unit?

One motor neuron and all the skeletal muscle cells stimulated by that neuron.

Name the parts of a neuromuscular junction.

Motor neuron, skeletal muscle fibers, axon terminals, calcium channels, synaptic vesicle, AcH, AcH receptors, sodium, potassium. Signup and view all the answers

What is acetylcholine and what does it do?

A compound that occurs throughout the nervous system and functions as a neurotransmitter, released from vesicles and attaches to protein receptors on the sarcolemma. Signup and view all the answers

Bundles of muscular fibers are called __. Muscular fibers are made up of cylindrical organelles called _.

Fascicles and myofibrils. Signup and view all the answers

List 4 functions of the muscular system.

Maintain posture, produce movement, stabilize joints, generate heat. Signup and view all the answers

What is the bare present zone in a relaxed sarcolemma?

H-Zone Signup and view all the answers

Thick protein filaments within the A-bands are called?

Myosin filaments. Signup and view all the answers

Which protein filament slides inward during a muscle contraction?

Actin filaments. Signup and view all the answers

What conducts a muscle impulse deep into a sarcoplasm?

T-tubules. Signup and view all the answers

What is the segment of a myofibril between two Z-discs called?

A bands. Signup and view all the answers

What causes muscles to appear striated?

Repeating units of sarcomeres. Signup and view all the answers

Neurotransmitters are stored in vesicles found in the _______.

Motor neuron axons. Signup and view all the answers

What does creatine phosphate serve to do?

Increases regeneration of ATP. Signup and view all the answers

What causes muscle fatigue and muscle cramps?

Lactic acid. Signup and view all the answers

What are the pros and cons of anaerobic glycolysis?

Pros = Can make ATP quickly. Cons = Produces far less ATP than aerobic production does. Signup and view all the answers

It is the function of the _______ to supply energy for muscle fiber contractions.

Mitochondria. Signup and view all the answers

What is fibromyalgia?

A common syndrome in which a person has long-term, body-wide pain and tenderness in the joints, muscles, tendons, and other soft tissues. Signup and view all the answers

What is Duchenne MD?

The most common form of MD and primarily affects boys. Caused by absence of dystrophin. Signup and view all the answers

What is Myasthenia Gravis?

An autoimmune disease in which your body destroys your AcH receptors. Drooping eyelids and trouble swallowing are first symptoms. Signup and view all the answers

What is Muscular Dystrophy?

A group of more than 30 genetic diseases characterized by progressive weakness and degeneration of the skeletal muscles. Signup and view all the answers

What type of muscular movement would arm circles be?

Circumduction. Signup and view all the answers

What type of muscular movement would standing on your tip toes be?

Plantar flexion. Signup and view all the answers

What type of muscular movement would carrying a lunch tray on the palms of your hands be?

Pronation. Signup and view all the answers

What type of muscular movement would giving someone the 'OK' sign be?

Opposition. Signup and view all the answers

The ________ appearance of skeletal muscles results from the arrangement of sarcomeres.

Striated. Signup and view all the answers

______ has the major responsibility for a certain movement.

Prime mover. Signup and view all the answers

_____ aids a prime mover in a movement and helps prevent rotation.

Synergist. Signup and view all the answers

______ opposes or reverses a prime mover.

Antagonist. Signup and view all the answers

A substance called a ______ crosses a synaptic cleft and stimulates the muscle fiber to contract.

Neurotransmitter. Signup and view all the answers

A __ can be described as cordlike and connecting muscles to bones, while an would be described as a fibrous sheet of connective tissue connecting muscles to muscles.

Tendon = Ligament Signup and view all the answers

______ is the shrinkage of a muscle due to lack of use.

Atrophy. Signup and view all the answers

The A bands are [light/dark] whereas the I bands are [light/dark].

Dark, light. Signup and view all the answers

What are the three types of muscles? Which type(s) are voluntary? Which type(s) are striated?

Skeletal muscle is striated and voluntary. Cardiac muscle is striated and involuntary. Smooth muscle is not striated and involuntary. Signup and view all the answers

What is meant by graded responses?

Different degrees of skeletal muscle shortening. Different combinations of muscle fiber contractions may give different responses. Twitch and unfused tetanus. Signup and view all the answers

How can you increase muscle endurance?

Aerobic exercise. Signup and view all the answers

How can you increase muscle size and strength?

Resistance exercise. Signup and view all the answers

Study Notes

Connective Tissue Layers

Endomysium: Encloses individual muscle fibers, providing support and insulating them.
Perimysium: Envelops fascicles (bundles of muscle fibers), contributing to the muscle's strength.
Epimysium: Surrounds the entire muscle, securing its structure while allowing flexibility.

Muscle Structure

Myofibrils: Composed mainly of two proteins, myosin and actin, which are essential for muscle contraction.
Fascicles: Bundles of muscular fibers, which are the building blocks of muscle tissue.
Sarcomere: The segment between two Z-discs in a myofibril, functioning as the basic unit of contraction.

Muscle Functionality

Motor Unit: A single motor neuron and all muscle cells it stimulates, crucial for muscle contraction.
Functions of the Muscular System: Maintains posture, enables movement, stabilizes joints, and generates heat.

Muscle Contraction Mechanism

Acetylcholine (ACh): A neurotransmitter released at the neuromuscular junction, binding to receptors to initiate muscle contraction.
Filament Sliding: During contraction, actin filaments slide toward the center of the sarcomere, while myosin filaments remain stationary.

Energy Sources and Fatigue

Creatine Phosphate: Enhances the regeneration of ATP, providing immediate energy for muscle contractions.
Muscle Fatigue: Caused by lactic acid accumulation during intensive exercise, leading to soreness and cramps.
Mitochondria: Organelles responsible for energy production required for sustained muscle contractions.

Muscle Pathologies

Fibromyalgia: Syndrome marked by widespread pain and tenderness in soft tissues.
Duchenne Muscular Dystrophy (MD): A genetic disorder primarily affecting boys, due to the absence of dystrophin.
Myasthenia Gravis: An autoimmune condition that destroys ACh receptors, causing muscle weakness.
Muscular Dystrophy: Encompasses over 30 genetic diseases causing progressive muscle weakness and degeneration.

Muscle Movement Types

Circumduction: Movements like arm circles involve a circular motion.
Plantar Flexion: Standing on tiptoes, extending the foot downward.
Pronation: Carrying items with the palms up.
Opposition: Making the "OK" sign with fingers.

Muscle Attributes

Striated Appearance: Resulting from the alternating light and dark bands formed by the arrangement of sarcomeres.
Prime Mover: The main muscle responsible for a specific movement.
Synergist: Assists the prime mover and stabilizes movement.
Antagonist: Opposes the action of the prime mover, providing balance.

Adaptations and Responses

Graded Responses: Variations in muscle contractions that result in different degrees of shortening and strength.
Improving Muscle Endurance: Achieved through aerobic exercise.
Increasing Muscle Size and Strength: Enhanced by resistance training.

Muscle Anatomy Notes

Tendons and Ligaments: Tendons connect muscles to bones, whereas ligaments connect muscles to other muscles.
Atrophy: Refers to muscle shrinkage due to disuse.
A and I Bands: A bands appear dark (thick filaments), while I bands appear light (thin filaments).

Muscle Types

Skeletal Muscle: Striated and voluntary, responsible for movement and posture.
Cardiac Muscle: Striated and involuntary, found only in the heart.
Smooth Muscle: Non-striated and involuntary, located in walls of hollow organs.

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Description

Test your knowledge of connective tissue layers and muscle structure with these flashcards from Human Anatomy Chapter 6. Understand key concepts such as endomysium, perimysium, and epimysium, along with the roles of myosin and actin in muscle fibers.