muscles

Question 1

What are the components of skeletal muscle tissue?

Answer 1

Skeletal muscle tissue consists of skeletal muscle fibers along with connective tissue membranes, which include epimysium, perimysium, and endomysium.

Question 2

What is the sarcolemma in muscle cells?

Answer 2

The sarcolemma is the plasma membrane of a muscle cell. Extensions of the sarcolemma form T-tubules, which create a network that helps transmit electrical signals deep into the muscle fibers. This system is essential for coordinating muscle contraction by ensuring that the action potential reaches all parts of the muscle fiber efficiently.

Question 3

What is the Endomysium in muscle anatomy?

Answer 3

The endomysium is the deepest layer of connective tissue that surrounds individual muscle fibers within fascicles. It provides insulation and support to each muscle fiber, allowing for the proper functioning and organization of muscle tissue during contraction and relaxation.

Question 4

What is the perimysium in muscle anatomy?

Answer 4

The perimysium is the connective tissue layer that surrounds each fascicle, which is a bundle of muscle fibers in skeletal muscle. This layer provides support and structure to the fascicles, helping to organize the muscle fibers and facilitating communication between them during contraction.

Question 5

Calcium’s Role in Muscle Contraction

Answer 5

An action potential in muscle cells triggers the release of calcium from sarcoplasmic reticulum (SR). Calcium binds to troponin, moving tropomyosin away from actin binding sites. Allows myosin connection with actin, muscle contraction. Actin & myosin interaction needs ATP for energy. After contraction, calcium goes back into SR, and muscle relaxes.

Question 6

How is oxygen managed in the body in relation to muscles?

Answer 6

Oxygen is carried by hemoglobin in the blood and is stored in myoglobin within muscle tissues. Myoglobin serves as an oxygen reservoir, facilitating the delivery of oxygen to muscle fibers during periods of high demand, such as exercise.

Question 7

What are the main functions of the muscular system?

Answer 7

1. Skeletal Movement: Muscles contract to move bones, creating body movement.
2. Posture Maintenance: Muscles help maintain posture and stabilize joints.
3. Heat Generation: Muscle contractions produce heat, aiding in the regulation of body temperature.

Question 8

What is a motor unit in muscle physiology?

Answer 8

A motor unit consists of a single motor neuron and all the muscle fibers it stimulates. Together, these components function as a unit to control muscle contractions, allowing for coordinated movements and varying degrees of muscle strength based on the number of motor units activated.

Question 9

What is the neuromuscular junction?

Answer 9

The neuromuscular junction is the synapse where a motor neuron connects with a muscle fiber. This junction allows the motor neuron to stimulate the muscle fiber, leading to electrical excitation and ultimately muscle contraction. It is a crucial site for communication between the nervous system and the muscular system.

Question 10

What is the synaptic cleft?

Answer 10

The synaptic cleft is the tiny space between the motor neuron and the muscle fiber across which a neurotransmitter must travel. This space is essential for transmitting the signal for muscle contraction, allowing the neurotransmitter to bind to receptors on the muscle fiber and initiate the process of excitation and contraction.

Question 11

What is acetylcholine (ACH) and its role in muscle contraction?

Answer 11

Acetylcholine is the primary neurotransmitter involved in muscle contraction. It is released from the neuron terminal into the neuromuscular junction, where it binds to receptors on the muscle fiber. This binding induces an electrical signal (action potential) that triggers the muscle contraction process.

Question 12

What is a sarcomere?

Answer 12

A sarcomere is the basic contraction unit of a muscle fiber, consisting of myosin (thick) and actin (thin) filaments. It is the structural and functional unit responsible for muscle contraction, working through the sliding filament mechanism to produce muscle shortening and force generation

Question 13

What are troponin and tropomyosin?

Answer 13

Troponin and tropomyosin are two proteins found in muscle fibers. They cover the binding sites on the actin molecule when the muscle is at rest, preventing myosin from attaching to actin. When calcium binds to troponin, it causes tropomyosin to shift, exposing the binding sites on actin and allowing muscle contraction to occur

Question 14

What are the steps involved in the sliding filament mechanism of muscle contraction?

Answer 14

1. Myosin heads bind to actin, forming cross bridges.
2. Myosin heads use stored energy to pull actin filaments together within the sarcomere, causing the cell to shorten.
3. Myosin heads detach using new ATP, allowing them to return to position for another “power stroke.”

Question 15

What is the sarcoplasm, and what does it contain?

Answer 15

The sarcoplasm is the cytoplasm of muscle cells, specifically in striated muscles. It stores calcium ions necessary for muscle contraction, as well as other substances like myoglobin, glycogen, and various organelles.

Question 16

The Process of Muscle Contraction

Answer 16

1. Signal to Muscle: The brain sends a signal to the muscle using a chemical called ACh.
2. Muscle Activation: ACh connects to the muscle, starting an electrical signal.
3. Signal Spreads: The electrical signal moves deep into the muscle.
4. Release Calcium: The muscle cell releases calcium to help with muscle movement.
5. Open Up Actin: Calcium opens spots on actin for myosin to attach.
6. Attach Myosin: Myosin grabs onto actin, like a hand grabbing something.
7. Pull the Actin: Myosin pulls actin together, making the muscle contract.
8. Release and Reset: Myosin releases actin and resets using energy (ATP).
9. Muscle Relaxation: Muscle relaxes when the brain stops sending signals.

Question 17

What are the benefits of exercise on the muscular and skeletal systems?

Answer 17

1. Improved balance and joint flexibility
2. Increased muscle size (hypertrophy)
3. Improved muscle tissue quality
4. Vasodilation (widening of blood vessels)
5. Strengthened heart muscle
6. Improved breathing and respiratory efficiency
7. Weight control
8. Stronger bones

Question 18

What are the different types of muscle contractions?

Answer 18

1. Partial contraction: Incomplete muscle activation.
2. Isotonic contraction: Tone/tension stays the same muscle length changes.
   A. Eccentric cont: Muscle lengthens.
   B. Concentric cont: Muscle shortens.
3. Isometric contraction: No change in muscle length, but there is an increase in tone/tension.

Question 19

What is the role of tendons and the arrangement of muscles in movement?

Answer 19

Tendons attach muscles to bones. For movement to occur, a muscle must be attached to a fixed part of the skeleton called the origin point, while the other end attaches to a movable part known as the insertion point. This arrangement allows muscles to generate movement by contracting and pulling on the bones.

Question 20

What are the roles of muscle groups in movement?

Answer 20

1. Prime Movers: These muscles are responsible for performing a specific movement.
2. Antagonists: These muscles relax to allow the prime mover to execute the movement.
3. Synergists: These muscles assist the prime mover by stabilizing the movement and adding additional force.

Question 21

What are the components of the anatomical lever system in the body?

Answer 21

1. Lever: The bone acts as the lever.
2. Fulcrum: The joint serves as fulcrum.
3. Effort: The muscle applies the effort.

Question 22

What are the characteristics, location, control, and action of smooth muscle?

Answer 22

Location: Found in the walls of hollow organs, blood vessels, respiratory passages, and other structures.
Characteristics: Tapered at each end, branching networks, non-striated.
Control: Involuntary.
Action: Produces peristalsis (wave-like contractions), contracts and relaxes slowly, and can sustain contractions over longer periods.

Question 23

What are the characteristics, location, control, and action of cardiac muscle?

Answer 23

Location: Found in the walls of heart.
Characteristics: Branching networks, special membranes (intercalated discs) between cells, single nucleus, lightly striated appearance.
Control: Involuntary.
Action: Pumps blood out of the heart, self-excitatory but influenced by the nervous system and hormones.

Question 24

What are the characteristics, location, control, and action of skeletal muscle?

Answer 24

Location: Attached to bones.
Characteristics: Long and cylindrical, multinucleated, heavily striated appearance.
Control: Voluntary.
Action: Produces movement at joints, stimulated by the nervous system, contracts and relaxes rapidly.

Question 25

What is a fascicle in muscle anatomy?

Answer 25

A fascicle is a bundle of muscle cells (muscle fibers) surrounded by a connective tissue sheath called the perimysium. Fascicles are grouped together to form the entire muscle, contributing to its structure and function.

Question 26

What is a muscle in terms of its structure?

Answer 26

A muscle is a bundle of fascicles (groups of muscle fibers) surrounded by a connective tissue layer called the epimysium. The epimysium helps protect and support the muscle, allowing it to function effectively during contraction and movement.

Question 27

What is a tendon, and what is its function?

Answer 27

A tendon is a band of dense regular connective tissue that connects muscles to bones. Tendons transmit the force generated by muscle contractions to the skeleton, enabling movement at the joints.

Question 28

What is a neuron (brain cell) and its function in the nervous system?

Answer 28

A neuron is a specialized cell within the nervous system that transmits information to other nerve cells, muscles, or gland cells. Neurons are the fundamental units of the nervous system and are responsible for processing and transmitting signals through electrical impulses and chemical neurotransmitters.

Question 29

What is the soma (cell body) of a neuron and its role?

Answer 29

The soma, or cell body, contains the nucleus and cytoplasm of the neuron. It receives information from other neurons through structures called dendrites that branch off the soma. The soma processes this information and plays a critical role in the overall functioning of the neuron.

Question 30

What is the function and structure of the axon in a neuron?

Answer 30

The axon is a long projection that carries information from the soma (cell body) to other cells, such as neurons or muscles. It is covered in myelin, formed by Schwann cells, which provides insulation and increases the speed of transmission. The axon terminals serve as the “output” part of the cell, relaying information to other neurons or muscles through synapses.

Question 31

What is excitability in muscle cells?

Answer 31

Excitability is the ability of muscle cells to transmit electric current. This property allows muscle cells to respond to stimuli, such as nerve impulses, leading to contraction and the generation of movement.

Question 32

What is contractility in muscles?

Answer 32

Contractility is the ability of a muscle to contract, referring to its capacity to generate tension and shorten in response to stimulation. This enables movement and force production.

Question 33

What is depolarization in muscle cells?

Answer 33

Depolarization is the process in which a change occurs inside a cell that alters the distribution of electrical charges, resulting in fewer negative charges inside the cell compared to the outside environment. It is a crucial step in generating an action potential, allowing for the transmission of electrical signals in neurons and muscle cells.

Question 34

What is an action potential in muscle cells?

Answer 34

An action potential is a change in electrical charge across a cell membrane triggered by an electrical impulse. This rapid change in charge stimulates muscle contraction and the transmission of signals in neurons. Electrolytes, which carry electrical charges, play a vital role in generating and propagating action potentials.

Question 35

What are actin and myosin, and what is their role in muscle contraction?

Answer 35

Actin and myosin are proteins found in all muscle tissue that work together to generate muscle contractions and movement. Actin forms the thin filaments, while myosin forms the thick filaments. The interaction between these proteins allows muscles to contract and relax, facilitating various movements in the body.

Question 36

What role does ATP play in muscle contraction?

Answer 36

ATP provides the energy needed for muscle contraction. It enables the interactions between actin and myosin, allowing myosin heads to detach from actin after a power stroke and prepare for the next contraction. Without enough ATP, muscles cannot contract effectively.

Question 37

What are fascicles in muscle tissue?

Answer 37

Fascicles are bundles of individual muscle fibers held together by connective tissue. This organization enables efficient muscle contraction and enhances the overall strength and functionality of the muscle.

Question 38

What is the epimysium in muscle tissue?

Answer 38

The epimysium is a connective tissue sheath that encases and defines the entire muscle. It forms the outermost layer and consists of tough fibrous connective tissue, providing structural support and protection while allowing the muscle to contract efficiently.

Question 39

What is the sarcoplasmic reticulum (SR) in muscle fibers?

Answer 39

The sarcoplasmic reticulum (SR) is a specialized type of smooth endoplasmic reticulum found in muscle fibers. It stores large amounts of calcium ions and is responsible for releasing calcium during muscle contraction and relaxation. The SR plays a crucial role in regulating muscle excitability and contraction.

Question 40

What is a first-class lever in the body, and give an example?

Answer 40

A first-class lever is the rarest lever system in the body, where the fulcrum is positioned in the middle, between the effort and the load. An example is the neck muscles, which help in tilting the head back.

Question 41

What is a second-class lever system, and why can’t it exist in the human body?

Answer 41

A second-class lever system cannot exist in the human body because the fulcrum is positioned at one end, with the load in the middle and the effort applied at the other end. This arrangement does not allow for effective movement in the human anatomy.

Question 42

What is a third-class lever system, and an example?

Answer 42

A third-class lever system, where the effort is applied between the fulcrum and the load. This type of lever is the most common in the body, such as during a bicep curl.