Muscular System Flashcards
What is the primary function of the muscular system?
The muscular system is responsible for producing movement, maintaining posture, stabilizing joints, generating heat through muscle contractions, and supporting bodily functions.
How many types of muscle tissue are there, and what are they?
Skeletal muscle – Voluntary, striated muscle attached to bones.
Cardiac muscle – Involuntary, striated muscle found in the heart.
Smooth muscle – Involuntary, non-striated muscle found in walls of internal organs (like the intestines and blood vessels).
What is the structure of skeletal muscle?
Skeletal muscles are composed of muscle fibers (cells), that are bundled into fascicles. These fibers contain myofibrils, which are made of sarcomeres (the functional units of muscle contraction).
What is a sarcomere?
A sarcomere is the smallest functional unit of muscle contraction.
What is muscle contraction?
Muscle contraction occurs when myosin filaments pull actin filaments towards each other, shortening the sarcomere and generating force. This process requires ATP and is triggered by the release of calcium ions.
What is the neuromuscular junction?
The neuromuscular junction is the synapse (connection) between a motor neuron and a muscle fiber. It allows for the transmission of signals that trigger muscle contraction.
What is the difference between isometric and isotonic contractions?
Isometric contraction: Muscle generates force without changing length (e.g., holding a plank).
Isotonic contraction: Muscle changes length while generating force (e.g., lifting weights).
Within Isotonic contractions what terms are used to determine the shortening and lengthen of a muscle?
Concentric - muscle shortens
Eccentric - muscle lengthens
What is muscle fatigue?
Muscle fatigue is the decline in the ability of a muscle to generate force
What causes muscle fatigue?
A lack of energy (ATP) or the accumulation of metabolic waste products like lactic acid.
What is the cardiac muscle?
The heart muscle.
What does involuntary mean?
The muscle actions automatically without thinking about it, not controlled by your brain (eg. breathing, heart beating)
What does voluntary mean?
You have to consciously think about doing that action. ( eg. raising your hand.)
What does striated mean? And what kind of muscles are striated?
Refers to the striped appearance of muscle tissue. Cardiac and skeletal muscles.
What is the role of calcium in cardiac muscle contraction?
When calcium is released from the sarcoplasmic reticulum, it binds to troponin, allowing myosin to bind to actin and initiate contraction.
Where is smooth muscle found?
Smooth muscle is found in the walls of hollow organs (eg. stomach, intestines, bladder.)
Where is the skeletal muscle found?
Attached to the skeleton - bones
What kinds of muscle fibres are there?
Oxidative, Glycolytic
What is an oxidative muscle fibre?
relys on aerobic respiration to make ATP. have more myoglobin, so they have longer endurance
What is a glycolytic muscle fibre?
Uses glycolysis/ anaerobic respiration to make ATP. Have less myoglobin so they tire easier
What is Myglobin?
protein that binds oxygen
What is Recruitment?
multiple motor neurons result in a stronger contractions
What is the difference between slow twitch fibres and fast twitch fibres?
Slow twitch fibres - Always oxidative, sustain contractions
Fast twitch fibres - combination of oxidative and glycolytic, sustain shorter contractions
What is tetanus?
Tetanus is a bacterial infection caused by Clostridium tetani where bacteria produces a toxin that causes severe, sustained muscle contractions, often starting in the jaw (hence “lockjaw”) and spreading throughout the body
What is myasthenia gravis?
autoimmune disease where antibodies block or destroy the receptors for acetylcholine at the neuromuscular junction, leading to muscle weakness
What is the primary source of energy for muscle contraction?
The primary source of energy for muscle contraction is ATP
What is aerobic respiration in muscles?
Aerobic respiration is the process by which muscles generate ATP using oxygen, producing carbon dioxide and water as byproducts. used during prolonged, moderate exercise.
What is anaerobic respiration in muscles?
Anaerobic respiration is the process of generating ATP without oxygen. It results in the production of lactic acid, which can cause muscle fatigue and soreness. Used during high-intensity, short-duration exercises.
What is the role of antagonistic muscles?
Antagonistic muscles work in pairs where one muscle contracts while the other relaxes to allow movement.
