APSC Test 2

Stretching

-It is passive

-There is no brain involvement

Pandiculation

-Subject is actively using the Mm, the brain is involved in the process

-Spontaneous pandiculation: yawning

3 types of muscles in the body

-Smooth muscle

-Cardiac Muscle

-Skeletal Muscle

Smooth muscle

-They can be found in the walls of the visceral organs, blood vessels and respiratory passageways

-It moves involuntarily

-Regulates the diameter of blood vessels or produce contractions of visceral organs

-The individual cells are spindle shaped and have a centrally located nucleus

Smooth muscle 

-Are regulated by the autonomic nervous system and may also contract in response hormonal stimulation, stretching, and other stimuli 

-The muscle contracts and relaxes slowly and can remain contracted for a long time

-No neuromuscular junction: diffuse junctions 

-ACh and/or norepinephrine: types of receptors on the smooth muscle membrane leads to excitation or inhibition 

Cardiac muscle

-Involuntary: pacemaker cells

-Striated: light and dark bands

-The membranes between the cells: specialized to allow electrical impulse to travel rapidly through them, so that contractions can be better coordinated

Skeletal Muscle

-These muscles are attached to bones and produce movement at the joints

-Skeletal muscle cells appear heavily striated

-The cells are very long and cylindrical and have multiple nuclei per cell

-Such cells can contract as a large unit when stimulated

-The nervous system stimulates skeletal muscle to contract and the tissue usually contracts and relaxes rapidly

Megaesophagus 

-Dilatation of the esophagus

-Food is not properly conducted from the mouth to the stomach 

-Affected pets are at risk for aspiration pneumonia: food or water is regurgitated then inhaled, which can lead to fluid and/or bacteria getting into the lungs

Speed of Esophageal Transit

Dog: 75-100 cm/sec

Cat: 1-2cm/sec

Muscle type

Dog: entirely striated

Cat: cranial 2/3 striated, caudal 1/3 smooth

Myopathies 

-Diseases that primarily cause damage to muscles or muscle tissues

-They may be present at birth or occur due to nutritional imbalances, injury, metabolic disturbances, cancer, or ingestion of a poisonous substance 

Myositis

-Inflammatory reaction in muscle

-Common causes are infections, parasitic diseases, and immune-mediated conditions