Skeletal and Cardiac Muscle Quiz

Electrical signals spread uniformly through heart chambers.

Spindle-shaped and lack striations.

Moves substances through internal pathways.

Cardiac muscle cells connect, allowing coordinated contractions.

Smooth muscle cells have a central nucleus; cardiac muscle cells don't.

Cardiac muscle has a branching structure; skeletal muscle doesn't.

Skeletal muscles are under voluntary control.

A motor neuron and all the muscle fibers it controls form a motor unit.

Cardiac muscle typically has one nucleus per cell; skeletal muscles can have many.

Skeletal muscle is primarily responsible for movement.

Cardiac muscle pumps blood throughout the body.

Skeletal muscle fibers are multinucleated and striated.

Skeletal muscles are involved in facial expressions.

Knowing the specific organism causing infection allows for informed decisions regarding treatment, prevention, and public health management.

Commonly collected samples for infectious disease testing include urine, swabs (wounds, throat, etc.), blood, stool, and sputum.

Samples obtained from deep within the body, such as lung fluid (bronchoscope), spinal fluid (lumbar puncture), bone marrow (biopsy), or tissue (aspiration or biopsy).

Directly visualizing microorganisms in clinical samples using light microscopy (bacteria, fungi, parasites) or electron microscopy (viruses).

Growing microorganisms in the lab to identify them based on their growth characteristics and metabolic properties.

Identifying specific antigens (molecules recognized by the immune system) associated with an organism in clinical samples.

Amplifying and identifying specific sequences of RNA or DNA belonging to a particular organism in a sample.

Measuring the levels of specific antibodies (immune system proteins) in the blood to indicate past or present infection.

Using antibodies tagged with fluorescent dyes to identify specific pathogens in cellular samples.

Antigen detection tests are rapid, specific, easy to perform, and not affected by antibiotics. However, they can only detect one pathogen per test, have lower sensitivity than molecular techniques, and do not provide antimicrobial sensitivity data.

Antigen tests for COVID-19 involve swabbing nasal or pharyngeal areas, adding the swab to a solution, and then capturing viral antigens on a test strip for visualization. These tests are rapid but have lower sensitivity than PCR tests.

Antibody responses change over time. IgM (early antibody) is typically positive during acute infection, while IgG (long-lasting antibody) is more persistent. This pattern can help differentiate recent infection from past infection or immunity.

Polymerase chain reaction (PCR) amplifies small amounts of DNA or RNA, making it possible to detect pathogens in a sample even when they are present in very low numbers.

PCR offers high sensitivity and specificity, allowing for rapid and accurate diagnosis, identification of antimicrobial resistance, and improved clinical decision-making. It also plays a crucial role in public health surveillance and identification of new pathogens.

Antigen detection is used for acute viral infections (COVID-19, HIV), serology for diagnosing some acute infections and monitoring chronic infections (HIV, hepatitis), and nucleic acid amplification (PCR) for a wide range of viral infections, particularly in immunocompromised individuals.

Microscopy and culture remain the cornerstones of diagnosing bacterial infections. Antigen detection tests are used for specific bacteria like Streptococcus pneumoniae, while PCR is becoming more common for rapid diagnosis, particularly in tuberculosis.

Microscopy is used for fungal elements in clinical specimens, culture remains the mainstay of diagnosis and identification, antigen detection helps diagnose invasive fungal infections (aspergillus, candida), and PCR is increasingly used in immunocompromised hosts.

Microscopy is the most common test, particularly for blood (malaria), urine (schistosomiasis), and stool (amoeba, worms). Antigen detection is becoming more common for malaria diagnosis. PCR is emerging in specialized settings.

The 'window period' refers to the time between acquiring a pathogen and the development of detectable antibodies against that organism. During this period, serological tests may be negative, making diagnosis challenging.

Identifying the organism causing an infection allows for targeted treatment, reduces the risk of antimicrobial resistance, improves patient outcomes, aids in public health surveillance, and facilitates contact tracing of emerging or high-risk pathogens.

Treatment of an infection without a definitive diagnosis, but based on clinical judgment and likely culprits.

Determining which antibiotics are effective against a specific isolated organism to guide clinical treatment decisions.

The most commonly used tests for identifying microorganisms and their antimicrobial sensitivity patterns include microscopy, culture, serology, antigen detection, and nucleic acid amplification (PCR).

A component of the fungal cell wall, specifically found in Aspergillus species. Detection of galactomannan in clinical samples can aid in the diagnosis of aspergillosis.

A component of the fungal cell wall, found in both Aspergillus and Candida species. Detection of beta-glucan may suggest invasive fungal infection.

A procedure involving the insertion of a needle into the spinal canal below the spinal cord to obtain a sample of cerebrospinal fluid (CSF). This sample is used to diagnose infections of the brain and meninges.

A parasitic infection caused by worms belonging to the Schistosoma genus. These worms are found in freshwater snails and are transmitted through the water.

A type of pneumonia caused by the bacterium Legionella pneumophila found in water sources. Infection occurs through inhaling contaminated water droplets.

An infection of the membranes (meninges) surrounding the brain and spinal cord. Meningitis can be caused by bacteria, viruses, fungi, and other organisms.

The soft, spongy tissue found within the center of bones. It is responsible for producing blood cells, making it susceptible to various infections.

A bacterium that causes syphilis. It is a spirochete, meaning it has a corkscrew shape, and is transmitted through sexual contact.

Bacteria that appear in pairs. Examples include Streptococcus pneumoniae and Neisseria meningitidis, both of which can cause severe infections.