Skeletal Muscle Contractile Mechanisms Quiz

Common symptoms of nicotine withdrawal include lightheadedness, night sweats, low mood, sore throat, increased coughing, increased appetite, and weight gain.

NRT can help reduce withdrawal symptoms, cravings, and the urge to smoke, making it easier for individuals to quit. It provides a steady, controlled dose of nicotine without the harmful effects of cigarette smoke.

Asthma is a reversible obstructive lung disease characterized by airway inflammation and hyperresponsiveness, while COPD is a non-reversible obstructive lung disease with chronic airflow limitation due to airway and alveolar damage. Asthma treatment often involves inhaled corticosteroids and short-acting beta agonists (SABA), while COPD treatment generally focuses on long-acting bronchodilators like LABA and LAMA.

<p>Key findings suggestive of asthma include a 12% or greater increase in forced expiratory volume in one second (FEV1) or a 200 ml increase in lung volume after administering a short-acting beta agonist (SABA), indicating reversible airflow obstruction.</p> Signup and view all the answers

<p>Smoking has detrimental effects on both the smoker and non-smokers. For smokers, it causes numerous diseases like lung cancer, heart disease, and respiratory illnesses, and shortens life expectancy. Secondhand smoke exposure puts non-smokers at increased risk for respiratory diseases, lung cancer, and heart disease.</p> Signup and view all the answers

<p>Compact bone is denser and stronger, containing osteons with a central canal (Harversian canal) surrounded by concentric rings of matrix. Spongy bone is lighter and less dense, containing red or yellow bone marrow.</p> Signup and view all the answers

<p>Osteoblasts form bone, osteoclasts break down bone, and osteocytes are mature bone cells that maintain bone tissue.</p> Signup and view all the answers

<p>Mechanical stress, like exercise, stimulates bone remodeling by increasing osteoblast activity. It helps to maintain bone density and strength.</p> Signup and view all the answers

<p>RA is an autoimmune disease where the immune system attacks the joints, while osteoarthritis is a degenerative condition caused by wear and tear on the joints.</p> Signup and view all the answers

<p>Symptoms include joint pain, stiffness, swelling, fatigue, and sometimes rheumatoid nodules, fever, lack of appetite, and weight loss.</p> Signup and view all the answers

<p>The goals are to reduce disease activity, improve quality of life, and prevent joint damage.</p> Signup and view all the answers

<p>Calcium ions are released from the T-tubules and sarcoplasmic reticulum (SR), triggering the sliding filament mechanism and muscle contraction.</p> Signup and view all the answers

<p>Cardiac muscle has a long refractory period, preventing the summation of muscle twitches and therefore tetanic contraction. This ensures a regular heartbeat and prevents muscle fatigue.</p> Signup and view all the answers

<p>The force of contraction is regulated by the amount of blood returning to the heart (preload), the resistance the heart has to pump against (afterload), and the contractility of the heart muscle.</p> Signup and view all the answers

<p>Electromechanical coupling involves the depolarization of the smooth muscle membrane triggering Ca2+ release, while pharmacochemical coupling involves the release of chemical messengers, like neurotransmitters or hormones, stimulating Ca2+ release.</p> Signup and view all the answers

<p>Osteoporosis presents with a loss of bone mass, structural deterioration, and increased risk of fractures. It is often asymptomatic until a fracture occurs.</p> Signup and view all the answers

<p>Bisphosphonates like alendronic acid are the first-line treatment for postmenopausal women.</p> Signup and view all the answers

<p>Antinuclear Antibodies (ANAs), abnormal B and T lymphocytes and the characteristic IMDAMNSHARP symptoms are the main hallmarks of SLE.</p> Signup and view all the answers

<p>Gout is caused by a buildup of uric acid in the body, leading to the formation of urate crystals in the joints and tissues, causing inflammation and pain.</p> Signup and view all the answers

<p>Weight management, a low-purine diet, adequate hydration, and limiting alcohol consumption are important non-pharmacological strategies for managing Gout.</p> Signup and view all the answers

<p>The primary function of the respiratory system is gas exchange between the body and the environment, enabling the uptake of oxygen and the removal of carbon dioxide.</p> Signup and view all the answers

<p>Surfactant, produced by the bronchi, lines the alveoli and prevents them from collapsing during exhalation. It also helps to reduce surface tension, allowing for efficient gas exchange.</p> Signup and view all the answers

<p>The alveoli are thin-walled air sacs in the lungs that are surrounded by capillaries. The blood-gas interface is the barrier formed by the alveolar epithelium, interstitial space, and capillary endothelium, allowing for rapid diffusion of oxygen and carbon dioxide between the air and blood.</p> Signup and view all the answers

<p>The C-shaped rings of cartilage in the trachea provide structural support, preventing its collapse during inhalation and ensuring that air can pass through freely.</p> Signup and view all the answers

<p>The respiratory system utilizes the ciliated columnar epithelium lining the airways and goblet cells that produce mucus to trap and expel inhaled particles. The cilia sweep the mucus upward, towards the pharynx, where it can be swallowed or expelled as phlegm.</p> Signup and view all the answers

<p>Type I cells are responsible for gas exchange, while Type II cells produce surfactant to reduce surface tension and prevent the alveoli from collapsing.</p> Signup and view all the answers

<p>Pleural fluid acts as a lubricant, reducing friction between the pleura surrounding the lungs and the chest wall during breathing.</p> Signup and view all the answers

<p>The diaphragm is a dome-shaped muscle that contracts during inspiration, flattening and increasing the volume of the thoracic cavity, thereby drawing air into the lungs.</p> Signup and view all the answers

<p>Inspiration involves the contraction of the external intercostal muscles and the diaphragm, while expiration primarily relies on the relaxation of these muscles, with the help of internal intercostal muscles.</p> Signup and view all the answers

<p>V/Q matching refers to the balance between the amount of air reaching the alveoli (ventilation) and the blood flow through the surrounding capillaries (perfusion). This balance ensures optimal gas exchange.</p> Signup and view all the answers

<p>The intercostal muscles play a crucial role in breathing by providing structural support to the rib cage and facilitating its movement during inspiration and expiration.</p> Signup and view all the answers

<p>Increased arterial PCO2 levels (hypercapnia) trigger an increase in ventilation to expel excess CO2 and restore normal blood gas levels.</p> Signup and view all the answers

<p>Central chemoreceptors are located in the brain stem and respond primarily to changes in CSF pH, while peripheral chemoreceptors are located in carotid and aortic bodies and respond to changes in blood PO2, PCO2, and pH.</p> Signup and view all the answers

<p>Lung receptors, such as stretch receptors and irritant receptors, provide feedback to the respiratory centers in the brain stem, influencing breathing patterns and depth.</p> Signup and view all the answers

<p>Breathing is regulated by both neural (brain stem and lung receptors) and chemical (chemoreceptors) control mechanisms, which adjust the frequency and depth of breathing to maintain appropriate oxygen and carbon dioxide levels in the blood.</p> Signup and view all the answers

<p>Skeletal muscle is organized in a hierarchical structure. A whole muscle is composed of bundles of muscle fibers, each muscle fiber being a single muscle cell. Each muscle fiber contains multiple myofibrils, which are long cylindrical structures running the length of the fiber. Myofibrils are composed of repeating units called sarcomeres, which are the functional units of muscle contraction. Within each sarcomere are thick and thin filaments, the myofilaments. Thick filaments are composed of the protein myosin, while thin filaments are composed of the proteins actin, tropomyosin, and troponin.</p> Signup and view all the answers

<p>The sliding filament theory states that muscle contraction occurs due to the sliding of thin filaments (actin) past thick filaments (myosin) within the sarcomere. Myosin heads bind to actin filaments, forming cross-bridges. The myosin heads then use ATP to pivot, pulling the actin filaments towards the center of the sarcomere. This shortening of the sarcomere results in muscle contraction. The cycle of cross-bridge formation, pivoting, and detachment requires the hydrolysis of ATP.</p> Signup and view all the answers

<p>The sarcoplasmic reticulum (SR) is an elaborate network of membrane-bound tubules that surrounds each myofibril. It stores and releases calcium ions (Ca2+), which are essential for muscle contraction. T-tubules are invaginations of the plasma membrane that extend deep into the muscle fiber, forming a network that closely interacts with the SR. When an action potential travels down a T-tubule, it triggers the release of calcium from the SR. This mechanism is crucial for excitation-contraction coupling, the process by which an electrical signal triggers muscle contraction.</p> Signup and view all the answers

<p>In a relaxed muscle, tropomyosin blocks the myosin binding sites on actin, preventing cross-bridge formation. Troponin is a complex of three proteins that binds to tropomyosin and actin and regulates the position of tropomyosin. When calcium ions bind to troponin, it causes a conformational change in the troponin-tropomyosin complex, exposing the myosin binding sites on actin. This allows myosin to bind to actin and initiate muscle contraction. In the absence of calcium, the troponin-tropomyosin complex blocks myosin binding, keeping the muscle relaxed.</p> Signup and view all the answers

<p>The length-tension relationship describes the relationship between the initial length of a muscle fiber and the maximal force it can generate. Muscle force is maximal at an optimal sarcomere length, where there is an optimal overlap of actin and myosin filaments. At shorter lengths, the filaments are compressed, reducing the number of potential cross-bridges. At longer lengths, the filaments are too far apart, leading to a reduced number of interactions. Optimal overlap maximizes the number of potential cross-bridges, leading to the greatest force generation.</p> Signup and view all the answers

<p>A twitch is the mechanical response of a muscle fiber to a single action potential. It consists of a brief period of contraction followed by relaxation. Tetanus refers to a sustained muscle contraction, resulting from a series of action potentials that occur close enough in time to prevent the muscle from relaxing completely between stimuli. A single twitch produces a relatively weak force. As the frequency of action potentials increases, the muscle fiber experiences summation of twitch forces, leading to a stronger contraction. At high frequencies, the muscle can reach a state of fused tetanus, where the contractions are so rapid that they appear smooth and sustained.</p> Signup and view all the answers

<p>A motor unit consists of a single motor neuron and all the muscle fibers it innervates. The force of a muscle contraction can be controlled by recruiting different numbers of motor units. When a greater force is needed, more motor units are activated. This process, known as motor unit recruitment, allows for fine control of muscle force, ranging from subtle movements to powerful contractions.</p> Signup and view all the answers

<p>Fast muscle fibers (Type II) contract and relax quickly, generating high forces but with limited endurance. They are typically white due to a lower content of myoglobin. Slow muscle fibers (Type I) contract and relax slowly, generating lower forces but with greater endurance. They are typically red due to a higher content of myoglobin. Fast fibers are adapted for rapid, powerful movements like sprinting or jumping, while slow fibers are suited for sustained activities like maintaining posture or endurance running. Fast fibers have a higher proportion of glycolytic enzymes for rapid ATP production, while slow fibers have a higher proportion of oxidative enzymes for sustained ATP production.</p> Signup and view all the answers

Strategies to help individuals stop smoking, including NRT and CBT.

Treatment options like patches, gums, or sprays that provide nicotine without smoke.

Asthma is reversible with treatment, while COPD is chronic and irreversible.

A lung function test that measures FEV1 and FVC to assess respiratory health.

A key measurement in spirometry indicating airflow obstruction; normal is over 0.7.

A basic rod-like unit of a muscle cell, composed of sarcomeres.

The functional unit of a muscle fiber, defined as the segment between two Z lines.

The process by which muscle fibers contract, involving the sliding of actin and myosin filaments past each other.

The process by which myosin heads attach to actin filaments to produce muscle contraction.

The relationship describing how muscle force varies with the length of the muscle before contraction.

The physiological process linking muscle excitation to contraction; involves action potentials and calcium ions.

Twitch is a single contraction; tetanus is a sustained contraction due to rapid stimulation.

The process of activating more motor units to increase muscle contraction strength.

Cells that facilitate gas exchange in the lungs.

Cells that produce surfactant to reduce surface tension in the lungs.

The space between the pleura surrounding the lungs, contains pleural fluid.

The process of taking in oxygen by breathing in.

The process of expelling carbon dioxide by breathing out.

The ratio of air reaching the alveoli (ventilation) to blood flow in the pulmonary capillaries (perfusion).

Sensory receptors that respond to changes in the chemical composition of the blood, particularly CO2, O2, and pH.

Muscles located between the ribs that assist with breathing by moving the ribs.

The main muscle used in breathing, separating the thoracic and abdominal cavities.

Rapid or deep breathing that results in reduced carbon dioxide levels in the blood.

A disorder characterized by loss of bone mass and structural deterioration, leading to increased fracture risk.

First-line treatment for osteoporosis in postmenopausal women, e.g., Alendronic acid.

Key markers in the diagnosis of Systemic Lupus Erythematosus (SLE).

Includes immunoglobulins, molar rash, arthritis, renal disease, and other systemic features.

An inflammatory arthritis caused by high uric acid levels leading to crystal formation in joints.

Long-term treatment for gout that includes medications like Allopurinol and Febuxostat.

Includes gas exchange, pH regulation, and protection against pathogens.

Tiny air sacs in the lungs where gas exchange occurs.

The windpipe that connects the larynx to the bronchi, lined with ciliated cells.

The part of the throat that serves both respiratory and digestive systems.

Bone provides structure, protection, movement, storage, and blood cell production.

There are two types of bone: compact (dense and strong) and spongy (light and hollow).

The three main types are osteoblasts (build bone), osteoclasts (break down bone), and osteocytes (maintain bone).

Bone remodeling is regulated by mechanical stress and hormones, maintaining balance among bone cells.

RA is an autoimmune disease causing inflammation and damage to joints and bones.

Common symptoms include joint pain, stiffness, swelling, fatigue, and weight loss.

Cardiac muscle is striated, involuntary, and pumps blood via coordinated contractions.

Smooth muscle is non-striated, controls involuntary movements in hollow organs.

Osteoarthritis is joint wear and tear, causing pain and decreased movement.