Muscular system Flashcards
Acetylcholine
Neurotransmitter at neuromuscular junctions. It is required for nerve impulses and muscle movement
Aerobic respiration
Aerobic – with oxygen. Requires oxygen to generate ATP. Occurs in mitochondria. Produces 38 ATP molecules (net of 36).
Oxygen and (glucose) = carbon dioxide + water + energy
Anaerobic respiration
An = without, aerobic = with oxygen. Allows cells to produce ATP in the absence of oxygen. Occurs in cytoplasm via glycolysis. Produces a net of two ATP molecules. Intensive short-term activity.
Glucose = lactic acid and energy
Arrector pili
Arrector pili (Arrector = to raise, Pili = hair). Muscles that help raise hair in the skin
ATP; Adenosine triphosate
Essential for effective muscle activity; muscles require large quantities of ATP (energy). ATP is released with Calcium to help contract muscle, and magnesium to help relax muscle. Two main pathways for ATP synthesis; aerobic and anaerobic respiration
Autorhythmic
Generates its own rhythm of contraction (auto = automatic, rhythmic = rhythm)
Minerals
Calcium, iron, sodium, magnesium, potassium; Essential for effective muscle activity;
Calcium - released from storage in the sarcoplasmic reticulum, causing the myosin and actin to bond & shorten the muscle fibre e.g. contraction
Collagen fibres
Collagen fibres in connective tissues assist to tightly intermingle with other structures
Connective tissue with muscle cells
Skeletal muscles consist of muscle fibres bound by connective tissue; Epimysium (whole muscle), Perimysium (fascicle) and Endomysium (muscle cells/fibers)
Creatine phosphate
A protein unique to muscles & is an energy storage form. Creatinine is a by-product from the breakdown of creatine phosphate
Fibril
Fibre
Functions;
Heat production (Thermogenesis); Helps maintain normal body temp (36.5 - 37.5) e.g. shivering
Movement; Results from muscular contraction
Movement of substances; move glycogen and oxygen around the body
Posture (maintaining); stabilising joints, posture and balance through continued partial muscle contraction
Storage of substance; storing glycogen and oxygen
Globin
A sphere / protein
Glycolysis
Breaking down of glucose (as in anaerobic respiration). (Glyco = sugar, lysis = break down)
Homeostasis - muscular system
Within all body systems, muscle tissue; produces movement, stabilises body position, moves substances within the body, produces heat to help maintain body temperature.
Hyperplasia
Increase in number (Hyper = Beyond normal, plasia = formation or development)
Hypertrophy
Increase in size (Hyper = Beyond normal, trophy = development)
Lactic acid
Produced during anaerobic respiration – lowers muscle pH and causes muscle fatigue
Lytic
To release
Mechanics
Muscles can be; Prime movers, antagonists, synergists and fixators depending on movement.
Prime movers; Depending on the movement, one muscle is the prime mover, while the other is the antagonist
Synergists; Assists the prime mover in its action
Antagonists; Most muscles are arranged in antagonistic pairs over a joint e.g. bicep brachii / tricep brachii
Fixators; Keeps the origin bone stable while a prime mover contracts
Mitochondria
Used for aerobic respiration (located close to myolglobin)
Muscle hypertrophy
Muscle growth. Growth hormone, testosterone and thyroid hormones promote muscle hypertrophy
Muscle types
Three muscle types in the body = skeletal, cardiac and smooth
Myo
Muscle
Myoblasts
Cells that fuse together and make muscle fibres
Myocardia
Heart muscle. Myo = muscle, Cardia = heart.
Myoglobin
Red coloured iron and oxygen binding protein
Neuro
Nerves
Neuromuscular Junction (NMJ) (Role)
1) The meeting point (synapse) where motor neurons meet a muscle fibre
2) The neuron ending is the synaptic end bulb, which contains vesicles that store the neurotransmitter acetylcholine
3) Acetylcholine diffuses across the gap and causes the nerve impulse to continue along the sarcolemma
4) the motor end plate describes the location where motor neurons terminate in tiny pads on the muscle fibre
5) the strength of the muscle contraction depends on the number of neurons that are conducting an electrical impulse at one time, as well as the frequency of impulses
NMJ; Action potential
Nerve impulses that travel along nerves to muscles to trigger muscle contraction
NMJ; Motor end plate
Describes the location where motor neurons terminate in tiny pads on the muscle fibre
Properties of muscle
Contractility = contract / shorten
Excitability = conduct an electrical current
Extensibility = stretch
Elasticity = spring (back)
Red muscle fibres
Large quantity of myoglobin, small diameter fibres, aerobic respiration, lots of mitochondria, sustained activity, little/no fatigue
Respiratory Diaphragm
Attaches to the lower 6 ribs, sternum & upper lumbar spine. When contracts, it increases the space for air to enter the lungs
Skeletal muscle: Fast glycolytic
White colour, anaerobic, least mitochondria/myoglobin, fatigues quickly, good for weights, large diameter
Skeletal muscle: Fast oxidative-glycolytic (FOG)
White/pink colour, aerobic/anaerobic, less mitochondria/myoglobin, resistant to fatigue, good for walk/sprinting, intermediate diameter
Skeletal muscle: Slow oxidative (SO) fibre
Dark red colour, aerobic, high mitochondria and myoglobin, long duration for fatigue, good for endurance, small diameter
Skeletal muscles; arm
Deltoid, Biceps brachii, Triceps brachii, Flexor carpi muscle, Extensor carpi muscle
Skeletal muscles; back
Supraspinatus, Psoas, Latissimus dorsi, quadratus lumborum, Erector spinae
Skeletal muscles; chest/abdomen
Pectoralis major, Rectus abdominis, Internal and external obliqueds
Skeletal muscles; face
Occipitofrontalis, orbicularis oculi, orbicularis oris, masseter, temporalis
Skeletal muscles; Legs
Gluteus maximus, Piriformis, Hamstring, Rectus femoris, Thigh adductors, Tibialis anterior, Soleus, Gastrocnemius
Skeletal muscles; neck
Sternocleidomastoid, Trapezius
Sliding filament; contraction
Nerve impulses arrive at the neuromuscular junction
The action potential spreads along the sarcolemma and transverse tubules in the muscle cell releasing calcium (Ca) from storage in the sarcoplasmic reticulum.
Calcium and ATP cause the myosin head to bind to the actin filament next to it.
As the actin and myosin bind, this movement causes the filaments to slide over each other, therefore shortening the fiber.
Sliding filament; relaxation
Nerve stimulation stops (no nerve impulse)
Using magnesium and ATP, calcium is actively transported (pumped back) into storage, breaking the actin and myosin bond
Actin and Myosin slide back into starting positions, lengthening the fiber again (relaxation)
Magnesium makes muscle fibers less excitable and prevent myosin binding with actin
Structure of muscle;
Endomysium
Thin sheath of connective tissue that surrounds individual muscle fibres
Structure of muscle;
Epimysium
Connective tissue that surrounds entire muscle and attaches it to fascia and tendons
Structure of muscle;
Fascia
A sheet of connective tissue that covers skeletal muscle to organise, muscle & secure it to skin / provide stability.
Structure of muscle;
Fascicles
Bundles of between 10-100 muscle fibres bound together to form the entire muscle
Structure of muscle; Actin
Thin myofilaments that make up myofibrils (two types = (actin and Myosin.
Structure of muscle; Myocytes (muscle fibres)
Muscle cell. Skeletal muscle cells are long, cylindrical, striated and have multiple nucleuses (many mitochondria = lots of ATP synthesis = energy).
The cell membrane of a myocyte is the sarcolemma
Myoctyes are surrounded by endomysium (connective tissue)
Structure of muscle; Myofibrils
Cylindrical structures formed of bundles of protein filaments (myofilaments) within the muscle fibre (cell)
Surrounded by the sarcoplasm (cytoplasm)
Structure of muscle; Myofilaments
Two types; Actin (thin filaments) and Myosin (thick filament), they overlap to form sarcomeres (basic contractile unit of a myoctye)
Structure of muscle; Myosin
Thick myofilaments that make up myofibrils (two types = (actin and Myosin.
Structure of muscle; Perimysium
Connective tissue that surrounds Fascicles
Structure of muscle; Sarcolemma
Cell membrane of a skeletal muscle fibre
Structure of muscle; Sarcomeres
The basic contractile unit of striated muscle. Contains; H-zone = myosin, A-band = dark area where actin and-myosin overlap, I band = light area of actin, Z disc = actin arranged at 90’ angles, they separate sarcomeres
Structure of muscle; Sarcoplasm
Cytoplasm of a muscle cell. Stirred calcium to be released for muscle contraction
(sarco = flesh, plasm = fluid)
Structure of muscle; Sarcoplasmic reticulum
Stores calcium required for muscle contraction
Tendons
Attach skeletal muscles to the periosteum bone
Transverse tubules
Tubes that extend from the cell membrane into the muscle cells, help ensure electrical impulses are received inside the cell
Types of muscle; Non striated muscle
Contain cells that are randomly arranged (no stripes visible)
Type of muscle; Striated muscle
Contain cells that are aligned in parallel bundles (uniform pattern / visible stripes)
Type of muscle; Skeletal muscle
640 striated, voluntary muscles - attaches between bones & creates movement at joints (movement, posture, speech & breathing). Can’t divide; limited regeneration by satellite cells. 3 types: slow oxidative (SO), fast oxidative – glycolytic (FOG), fast glycolytic (FG)
Type of muscle; Smooth muscle
Non-striated involuntary muscle, under ANS control. Smallest type of muscle cell, containing a single elongated nucleus. Found in walls of blood vessels, airways, hollow organs (i.e. Stomach, bladder), iris, arrector pili. Can increase in number, regenerate from stem cells.
Type of muscle; Smooth muscle
Non-striated involuntary muscle, under ANS control. Smallest type of muscle cell, containing a single elongated nucleus. Found in walls of blood vessels, airways, hollow organs (i.e. Stomach, bladder), iris, arrector pili. Can increase in number, regenerate from stem cells.Types of Muscle:
Cardiac Muscle
Types of Muscle:
Cardiac Muscle
Striated, involuntary muscle – forms the heart muscle (myocardium). Only found in the heart. Autorhythmic.
White muscle fibres
Low quantity of myoglobin, large diameter fibres, anaerobic respiration, fast / strenuous work, fatigues quickly
Functions of muscular system
Movement
Movement of substances
Thermogenesis
Posture
