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Questions and Answers
What is denervation atrophy?
What is denervation atrophy?
Hypertrophy results in an increase in both the size and number of muscle fibers.
Hypertrophy results in an increase in both the size and number of muscle fibers.
False
Name one consequence of muscle degeneration and necrosis.
Name one consequence of muscle degeneration and necrosis.
Pale appearance of degenerated muscles
The three types of atrophy are denervation atrophy, disuse atrophy, and __________ atrophy.
The three types of atrophy are denervation atrophy, disuse atrophy, and __________ atrophy.
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Match the type of atrophy with its description:
Match the type of atrophy with its description:
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Which of the following describes calcification in muscle tissue?
Which of the following describes calcification in muscle tissue?
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Muscle repair cannot occur after necrosis.
Muscle repair cannot occur after necrosis.
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What is a potential visual indication of muscle degeneration?
What is a potential visual indication of muscle degeneration?
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Which muscle fibers are predominantly found in the pectoral muscles of chickens?
Which muscle fibers are predominantly found in the pectoral muscles of chickens?
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Skeletal muscle is exclusively responsible for movement and does not contribute to body homeostasis.
Skeletal muscle is exclusively responsible for movement and does not contribute to body homeostasis.
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What are the two types of changes that can occur related to skeletal muscle disease?
What are the two types of changes that can occur related to skeletal muscle disease?
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One possible clinical sign of skeletal muscle disease is __________.
One possible clinical sign of skeletal muscle disease is __________.
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Match the types of atrophy with their descriptions:
Match the types of atrophy with their descriptions:
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What role does skeletal muscle play with respect to blood vessels?
What role does skeletal muscle play with respect to blood vessels?
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Histopathology is important for determining muscle color during examination.
Histopathology is important for determining muscle color during examination.
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Name one portal entry for disease related to skeletal muscle.
Name one portal entry for disease related to skeletal muscle.
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What is a common sign associated with definitive cysts containing trillions of parasites?
What is a common sign associated with definitive cysts containing trillions of parasites?
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Myasthenia gravis can cause severe muscular fatigue after mild exercise.
Myasthenia gravis can cause severe muscular fatigue after mild exercise.
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What type of immune-mediated myositis is characterized by swollen painful jaws in dogs and bovines?
What type of immune-mediated myositis is characterized by swollen painful jaws in dogs and bovines?
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Myasthenia gravis can be classified into two types: _____ and acquired.
Myasthenia gravis can be classified into two types: _____ and acquired.
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Match the following neoplasias with their type:
Match the following neoplasias with their type:
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Which bacterium is primarily responsible for causing Black leg?
Which bacterium is primarily responsible for causing Black leg?
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Gas gangrene is caused by viral infections.
Gas gangrene is caused by viral infections.
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What is the primary pathological feature observed in muscles affected by Black leg?
What is the primary pathological feature observed in muscles affected by Black leg?
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___ is an idiopathic-immune mediated condition affecting skeletal muscles.
___ is an idiopathic-immune mediated condition affecting skeletal muscles.
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Match the following myositis related terms with their definitions:
Match the following myositis related terms with their definitions:
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Which of the following describes arthrogryposis?
Which of the following describes arthrogryposis?
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Myofibers hypoplasia results in an increased number of myofibers.
Myofibers hypoplasia results in an increased number of myofibers.
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What are the three types of atrophy mentioned?
What are the three types of atrophy mentioned?
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Arthrogryposis frequently leads to __________ due to joint rigidity.
Arthrogryposis frequently leads to __________ due to joint rigidity.
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Match the type of muscle alteration with its description:
Match the type of muscle alteration with its description:
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What is NOT a cause of arthrogryposis?
What is NOT a cause of arthrogryposis?
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Disuse atrophy occurs when there is damage to the nerve supply of the muscle.
Disuse atrophy occurs when there is damage to the nerve supply of the muscle.
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What is one of the characteristics of myofibers hypoplasia?
What is one of the characteristics of myofibers hypoplasia?
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Study Notes
Skeletal Muscle Structure
- Muscle fibers can be categorized into type I and type II fibers
- Type I fibers are known as "red" or "slow twitch" fibers and are responsible for endurance activities
- Type II fibers are known as "white" or "fast twitch" fibers and are responsible for short bursts of activity
- The pectoral muscles of chickens and birds are rich in type II fibers, while long-distance flying birds have pectoral muscles rich in type I fibers
- The distribution of fibers can affect the presence of certain diseases
Skeletal Muscle Function
- Involved in locomotion, posture, and fine motor movements
- Supports joint stability and plays a crucial role in proprioception
- Protects the body by absorbing impacts
- Contributes to body homeostasis by generating heat
- Stimulates blood vessels, assisting in blood pumping against gravity
Skeletal Muscle Examination
- Visual examination includes assessing color, volume, texture, and appearance
- Compare the affected muscle to the contralateral side if possible
- Assess muscle response to stimuli
- Microscopic examination through histopathology is essential to determine the underlying pathology
Skeletal Muscle Disease
- Intertwined with the peripheral nervous system as muscle function is driven by motor neuron innervation
- Diseases fall into two categories: neuropathic or myopathic
- Neuropathic disease involves a disruption in nerve signal transmission
- Myopathic disease affects muscle cell metabolism and function
Clinical Signs of Skeletal Muscle Disease
- Atrophy: decrease in muscle size
- Hypertrophy: increase in muscle size
- Swelling
- Weakness
- Pain
- Muscle spasms
- Abnormal gait
Disease Portal Entries for Skeletal Muscle Disease
- Injury: wounds, intramuscular injections, bone fractures
- External pressure
- Infection: blood pathogens, toxins, autoantibodies
- Inflammation: inflammatory cells
Skeletal Muscle Disease: Specific Conditions
- Developmental abnormalities
- Arthrogryposis: Congenital condition where fetuses and stillborn have small limbs with rigid joints
- Myofibers Hypoplasia: Hind limbs are affected, with a lower than expected number and diameter of myofibers
Degenerative Alterations
-
Atrophy:
- Denervation atrophy: Loss of muscle mass due to lack of nerve stimulation
- Disuse atrophy: Reduction in muscle mass due to inactivity.
- Malnutrition atrophy: Decrease in muscle mass due to lack of nutrients
-
Hypertrophy: Increase in muscle size due to an increase in workload or genetic selection
-
Degeneration and Necrosis: Myofiber injury can be reversible to a point of no return.
-
Calcification: Deposition of calcium in the muscle tissue, common in degeneration and necrosis.
-
Regeneration: Muscle repair involves satellite cells migrating to the center to form myoblasts and facilitate myofiber regeneration
Myopathies and Myositis
- Myopathies: Diseases of muscle tissue
- Myositis: Inflammation of muscle tissue
-
Types of myositis:
- Bacterial: Black leg (caused by Clostridium chauvoei), Gas gangrene (caused by Clostridium septicum, perfringens, chauvoei...)
- Viral: Foot and mouth disease
- Parasitic: Trichinosis, Cysticercosis, Sarcocystosis
- Idiopathic - immune mediated: Masticatory muscle myositis, Myasthenia gravis
- Neoplastic: Rhabdomyoma and rhabdomyosarcoma
### Black leg (Symtomatic Anthrax, Emphysematous Gangrene)
- Caused by Clostridium chauvoei
- A fatal disease in cattle, sheep, and goats
- Infection:
- Spores ingested from soil or the environment
- Spores germinate in the digestive tract, liver, or muscle
- Characterized by:
- Muscle injury
- Inflammation of the affected muscles
- Toxin production
- Edema
- Muscle necrosis
- Gas production (emphysema)
- Toxemia
- Death
- Pathology:
- Large masses of muscle (pectoral, pelvic, crural, scapular)
- Muscles are black with gas (emphysema)
- Subcutaneous edema
- Histopathology:
- Degeneration
- Edema
- Necrosis
- Emphysema
- Bacteria difficult to see
Gas gangrene (Malignant edema)
- Caused by Clostridium septicum, perfringens, chauvoei...
- Typically affects ruminants, horses, and pigs
- Cysts containing trillions of parasites are present
- Often no inflammatory response in the muscle tissue
- Important clinical signs include abortion
Idiopathic – immune mediated myositis (dogs and bovines)
- Masticatory muscle myositis: Bilateral swollen and painful jaws, often with atrophy
- Myasthenia gravis: Rare, sporadic disease in dogs and cats. Causes severe muscle weakness and fatigue after mild exercise.
- Types:
- Hereditary: Reduced acetylcholine (ACh) receptors
- Acquired: Antibodies against ACh receptors
- Treated with Neostigmine, an anticholinesterase drug
- Types:
Neoplasia
- Primary:
- Rhabdomyoma/Rhabdomyosarcoma
- Fibroma/Fibrosarcoma
- Lipoma/Liposarcoma
- Hemangioma/Hemangiosarcoma
- Lymphoma/Lymphosarcoma
- Secondary:
- Metastasis of sarcomas and carcinomas
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Description
Explore the complexities of skeletal muscle fibers and their functions. This quiz covers the differences between type I and type II fibers, their roles in various activities, and the importance of muscle in overall body function. Test your knowledge on muscle examination techniques and physiological contributions.
