PHS 201: Muscle Physiology Flashcards
What are the types of muscle tissue?
- Skeletal -Skeletal muscle is the type that attaches to our bones and is used for movement and maintaining posture
- Cardiac - It is only found in the heart and it pumps blood
- Smooth - found in organs of the body such as the G.I. tract. Smooth muscle in the G.I. tract moves food and its digested products
Characteristics of cardiac muscle
Branching cells
one or two nuclei per cell
striated
involuntary
medium speed contractions (not as fast as skeletal but faster than that of smooth muscle)
Smooth muscle characteristics
Fusiform cells
One nucleus per cell
Nonstriated
Involuntary
Slow wave-like contractions
Found in the walls of hollow organs
Skeletal muscle characteristics
Long cylindrical cells
many nuclei per cell
striated
involuntary
rapid contractions
Function of skeletal muscle
Produce movement
maintain posture and body position support soft tissues
guard entrance or exit
maintain body temperature
store nutrients reserves
What forms the tendon or aponeurosis of muscles
Endomysium perimysium and epimysium come together at ends of muscles to form connective tissue attachment to burn matrix i.e. tendon or aponeurosis
Role of the skeletal muscle muscular system
Supplies large amounts of oxygen supplies nutrients
carries away waste
Describe skeletal muscle fibers
They are very long
develop through fusion of mesodermal cells (myoblasts)
become very large
contain hundreds of nuclei
Nerve supply of skeletal muscle
Somatic nerves
Nerve supply of cardiac muscle
Autonomic nerves
Nerve supply of smooth muscle
Autonomic nerve fibers
Smooth muscle is also known as
Visceral muscle
What is fasciculi
The various groups in which muscle fibers are arranged in the connective tissue sheath that covers each fasciculus is called perimysium
What’s connected tissue sheath is directly beneath the facia of muscle
Epimysium
What is an Aponeurosis
Thin flat and stretched tough muscle tendon
What is sarcolemma
Plasma membrane that encloses each muscle fiber that lies beneath the Endomysium
Function of the endomysium
Each muscle fibers covered by a connective tissue layer called the Endomysium
What is the cytoplasm of the muscle
Sarcoplasm
Structures embedded within the sarcoplasm
Nuclei
Myofibril
Gogi apparatus
mitochondria
sarcoplasmic reticulum
ribosomes glycogen droplets occasional lipid droplets
What are Cohnheim’s areas or fields
These are groups in which some Myofibrils are arranged in
What is a sarcomere
The sarcomere is defined as the structural and functional unit of a skeletal muscle.
An arrangement of overlapping contractile proteins, actin and myosin within a myofibril to form light and dark striations.
Describe the skeletal muscle levels of organization
- A muscle is made of many muscle cells, called muscle fibers
1.1 bundles of muscle fibers are arranged in fascicles - A muscle fiber is packed full of long fiber-like contractile organelles called myofibrils
- Myofibrils are made up of contractile proteins- myosin and actin
- Myosin and actin are arranged in overlapping stripes, organized into a unit called the sarcomere
What is myosin?
Thick filament of within a myofibril
What is actin?
Thin filament within a myofibril
