Muscular System Flashcards
What are the 5 functions of muscle and explain each.
- Movement - a result of muscular contraction
- Maintaining Posture - stabilising joints, posture and balance through continued partial muscle contraction.
- Heat production - (Thermogenisis) Helping to maintain normal body temperature.
Shivering is described as involuntary contractions of the skeletal muscle. - Storage of substances such as Glycogen (long chain fatty acids) and Oxygen
- Movement of substances around the body e.g heart muscle pumping blood around the body.
Give five examples of muscle movement of substances around the body.
Heart - pumps blood around the body
Spincters - prevents out-flow from hollow organs
Smooth muscle in the blood vessels controls blood flow
Smooth muscle in the digestive tract moves food through and Urine in the urinary system.
Diaphragm - draws air into the lungs
What is a sphincter
a circular muscle
What does Thermo stand for
Heat
What does Genesis stand for
create
Name 4 muscle properties and what they do
Contractility - Ability to contract (shorten)
Excitability - Ability to create electric currents. Nerve impulses creates muscle contraction.
Extensibility - Allowing the muscle to stretch without damage.
Elasticity - Allowing the muscle to return to normal shape after contraction or extension. (spring)
Describe what Striated muscle cells look like and where do we find it.
Striated muscle cells are aligned in parallel bundles and is found in skeletal and cardiac muscle.
Describe what non striated muscle cells looks like and where is it found.
The cells are randomly arranged and is found in smooth muscle
How is striated muscle and non striated muscle seen under a microscope
Striated the stripes they form are visible. In non striated there are no stripes visible.
What are the 3 types of muscle and what are their key features
- Skeletal Muscle - Striated muscle, it attaches muscle to bone and permits movement at joints. It is a Voluntary muscle
- Cardiac Muscle - Striated muscle - forms the heart muscle only. Creates it’s own rhythmic contraction (autorhythmic). It is an involuntary muscle.
- Smooth Muscle - Non Striated muscle it is found in the walls of blood vessels, walls of the gut, Iris, stomach intestines and hair on the skin.
How many skeletal muscles do we have in our body
640
What percentage of our body weight do skeletal muscles account for?
40
What is Skeletal muscle covered in, what is it and what is it’s function?
It is covered in Fascia, it is a dense sheet of connective tissue that connects muscle to the skin, and provides a physical barrier around the muscle
What is a major component of Fascia
Collagen
Are skeletal muscles voluntary on involuntary?
Voluntary
What are the functions of skeletal muscles
Motion and posture, speech (larynx, lips, tongue) and breathing.
What does sarco mean
Flesh
What does plasm mean
meaning fluid
What does Myo mean
Muscle
What does Globin mean
Sphere/protein
What does Fibril mean
Relating to fibre
What else is a muscle fibre known as?
Muscle Cell
What is the name of a mature muscle cell and what are they formed from?
Myocytes and they are formed from immature cells called Myoblasts.
What is the name given to the cell membrane of skeletal muscle cells.
Sarcolemma
What is the equivalent to the Cytoplasm in Skeletal muscle cells.
Sarcoplasm
What are the tubes called that are found in muscle cells, where do we find them and what do they do?
Transverse Tubules - extend from the cell membrane into the muscle cells. They ensure that electrical impulses travelling along the muscle all get into the cell.
What Organelle do we find in abundant in skeletal and cardiac muscle.
Mitochondria
What is the organelle in Skeletal Muscle that stores calcium? Is this rough or smooth?
Sarcoplasmic Reticulum - It is smooth
Why do we need calcium in our muscles?
Calcium is needed for muscle contraction
What is the function of Myoglobin
Stores oxygen in muscles. This makes the muscle appear red.
Why do we need an abundance of mitochondria in our cardiac and skeletal muscles.
Because cardiac and skeletal muscle cells are metabolically active so require many mitochondria for energy in the form of ATP
What is skeletal muscle made up and how are they formed.
Made up of long cells called Myocytes (mature cells) that are formed by the fusion of lots of Myoblasts (Immature cells) in the embryo and they each have their own nucleus.
Can skeletal muscle fibres renew their cells. Explain
The number of skeletal muscle fibres each person has is set at birth. Once mature muscle cells are formed (becoming myocytes) they are no longer able to undergo mitosis. Muscle cells are able to grow in size but not in number. They have a limited regenerative capacity but the little they do have is done by satellite cells.
What are Myofibrils and how are they arranged?
Cylindrical structures formed of bundles of protein filaments within muscle fibre. They are contractile threads arranged in a striated pattern.
Myofibrils are made up of smaller filaments called xxxxxx
Myofilaments
What are the names of the 2 types of Myofilaments?
Myosin (Thicker filament)
Actin (thinner filament)
What to Myofilaments form?
They form sub units along the muscle called Sarcomeres’
What organelle are Myofibrils part of
Cytoskeleton
What is contraction of muscle on a cellular level referring too?
The sliding of Actin and Myosin Filaments
What is a sarcomere?
Basic unit of Striated muscle
What are the 4 areas of the sarcomere and describe each
H Zone - Myosin only
A Band - Dark area where Myosin and Actin overlap
I Band - light area of Actin only
Z Disc - filaments of actin that are arranged at 90 degree angles that separate the sarcomeres.
What do Myocytes contain
Myofibrils made up of smaller Myofilaments called Actin and Myosin
What does Mysium mean
Muscle connective tissue
Explain the structure of Myocytes
They are bundled together and surrounded by perimysium and form fascicles.
Fascicles accumulate together to form the entire muscle which is surrounded by the Epimysium.
The Epimysium provides an attachment for muscle to the periosteum of the bone.
What do collagen fibres do in muscle connective tissue do
It assists to tightly intermingle with other structures and apply forces in a very direct way.
What is the endomysium
a thin sheath that surrounds individual muscle fibres