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Discover the three types of muscles in the human body - smooth, cardiac, and skeletal - and how they enable movement, regulate blood flow, and facilitate bodily functions. Learn about muscle fibers, sarcomeres, and the process of muscle contraction and relaxation.
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KEY CONCEPT Muscles are tissues that can contract, enabling movement.
Humans have three types of muscle. • The muscular system moves substances throughout the body. • bones of the skeletal system • food through digestive system • blood through circulatory system • fluids through excretory system
SMOOTH MUSCLE CARDIAC MUSCLE SKELETAL MUSCLE • skeletal muscle • There are three types of muscle tissue. • smooth muscle • cardiac muscle
SKELETAL MUSCLE • Tendons connect muscle to bone. • Skeletal muscles are mostly voluntary. • Skeletal muscle attaches to the skeleton by tendons.
Smooth muscle around this artery allows the artery to regulate blood flow by shrinking and expanding. SMOOTH MUSCLE • Smooth muscle lines organs and is involuntary. • move food through digestive organs • empty liquid from the bladder • control width of blood vessels
CARDIAC MUSCLE • Cardiac muscle is found only in the heart. • pumps blood throughout body • controlled by pacemaker • contains more mitochondria than skeletal muscle cells
muscle fiber muscle Muscles contract when the nervous systems causes muscle filaments to move. • Muscle fibers are cells of the muscular system.
myofibril muscle fiber muscle • Myofibrils are long strands of protein in the muscle fiber.
muscle fiber muscle myofibril sarcomere • Sarcomeres contain filaments that cause contraction. • Each myofibril is divided into sarcomeres.
neuromuscular junction neuron MUSCLE • Neuron stimulates muscle at the neuromuscular junction.
RELAXATION myosin Z line M line CONTRACTION • Sarcomeres contain filaments that cause contraction. • Each myofibril is divided into sarcomeres. • Actin filaments are pulled during contraction. • Myosin filaments pull actin during contraction.
regulatory protein actin myosin Z line • Neurotransmitters cause calcium channels in the sarcomere to open. • Neuron stimulates muscle at the neuromuscular junction. • Calcium exposes binding sites. • Myosin binds to actin and pulls it. • As the sarcomere shortens, the muscle contracts.