skeletal and cardiac muscles

what are some characteristics of skeletal muscle cells?

they are elongated or tubular. they have multiple nuclei, which are located on the periphery of the cell (edge of the cell), and it is striated

what smaller bundles are muscles made up of?

fascicles, which are bundles of myofiber or myocytes.

what are fascicles surrounded by?

a connective tissue sheath called the perimysium

what is each muscle cell surrounded by?

a connective tissue known as the endomysium

what are the types of skeletal muscles?

1. circular

2. convergent

3. parallel

4. pennate muscles, which are

   • unipennate,

   • bipennate

   • multipennate

5. fusiform

what is the myofibril?

basic, rod-like organelle of the muscle cell that makes up the long, tubular cells of skeletal muscles

what are myofibers or myocytes?

the muscle cells

what is the sarcolemma?

the plasma membrane of a muscle cell

what is the sarcoplasm?

the cytoplasm of the muscle cell

what is the sarcosome?

the mitochondria of a muscle cell

what is the sarcomere?

the smallest and functional / contractile unit of a muscle

why is the endomysium important?

it is important to the physiology of muscle contraction as it electrically insulates the individual muscles from each other so that contraction can be done precisely

what is the mitochondria the site of?

energy production, or ATP synthesis, in the muscle cells, as in all other cells of the body with the exception of mature red blood cells

what are cardiac muscles?

striated, involuntary muscles that have actin and myosin filaments arranged in repeated units known as sarcomeres

how do cardiac muscles differ from skeletal muscles?

while they are similar in striations, they are shorter in length and are often branched cells

where is the nucleus of the cardiac muscle located?

they contain a single nucleus that is centrally located

what do cardiac muscles contain a large number of?

mitochondria, as they require a large amount of energy in the form of ATP

what is the cell membrane of cardiac muscle cells called, and what forms it?

sarcolemma, which is formed partially by intercalated discs

what structures do intercalated discs contain?

most notably, adherens junction, gap junctions and desmosomes

what do gap junctions of the heart allow?

easy movement of the action potential and they coordinate the contraction of the heart