Muscular System Flashcards
Name the 4 quadriceps
- Quadriceps = vastus medialis, vastus lateralis, rectus femoris > vastus intermedius is beneath/deep to the rectus femoris
- The Queen is Very Very Rich
Name the hamstrings
- Hamstrings = semimembranosus, semitendinosus, biceps femoris
- Hubert is a Silly Silly Bee
What is an aponeurosis?
Broad sheet of connective tissue by which some muscles attach to bone
Fascia
Thin casing of connective tissue that holds organs, blood vessels, bones, nerves and muscles in place
Point of origin vs insertion
- Origin: end of muscle attached to stationary bone, often proximal
- Insertion: end of muscle attached to moving bone, often distal
Name the 4 components of a skeletal muscle from most superficial to deepest
Epimysium, perimysium, fascicle, endomysium
Epimysium
Outer layer of connective tissue around a skeletal muscle
Perimysium
Connective tissue that bundles skeletal muscle fibres into fasciculi
Fascicle (plural fasciculi)
Bundle of skeletal muscle fibres
Endomysium
Loose connective tissue covering each skeletal muscle fibre
Muscle fibre
Single muscle cell
Sarcolemma
Plasma membrane of a skeletal muscle fibre
Sarcoplasm
Cytoplasm of a skeletal muscle fibre
Sarcomere
Shortens to allow skeletal muscle fibres to contract
What is the sarcoplasmic reticulum and what is its function?
- Specialised smooth ER of a muscle fibre
- Stores, releases and retrieves Ca2+ ions
Myofibril
Basic rod-like organelle of a skeletal muscle fibre
Name 4 characteristics of muscles
Excitability/irritability, contractility, extensibility, elasticity
Excitability/irritability
Ability of a muscle to receive and respond to stimuli
Contractility
Ability of a muscle to shorten forcibly
Extensibility
Ability of a muscle to be stretched/extended
Elasticity
Ability of a muscle to recoil to resting length
Name the types of muscle contractions
- Isotonic (concentric, eccentric)
- Isometric
Isotonic muscle contractions
When the muscle length changes during contraction i.e. concentric/eccentric
Concentric vs eccentric muscle contractions
- Concentric = muscle shortens during contraction e.g. bicep curl
- Eccentric = muscle lengthens during contraction e.g. tricep extension
BOTH TYPES OF ISOTONIC
Isometric muscle contractions
Tension is created but length of muscle does not change e.g plank/wall sit
Agonist vs antagonist
- Agonist: contracting muscle
- Antagonist: lengthening muscle
Active vs passive movements
- Active: effort exerted by individual to generate movement of affected body part
- Passive: someone helps to move affected body part, or no effort exerted by affected body part e.g. Pt uses right hand to pick up left arm
Benefits of active vs passive movements
- Active: improve muscle strength and mass, strengthen communication between brain and body
- Passive: increase ROM, prevent stiffness so Pt can move without pain
What is muscle fatigue and what is it caused by?
- Physiological inability to contract at desired speed/ strength despite stimuli
- Caused by depleted fuel stores and accumulation of waste products e.g. H+ ions. Short term fatigue during exercise is healthy
What is muscle tone and its function? Also describe abnormal muscle tone
- The continuous, passive partial contraction of muscle (healthy to have some muscle tone)
- Functions to maintain posture and stabilise joints
- Can be abnormal: flaccid = low muscle tone, spasticity = high muscle tone
What are muscle cramps and what are they thought to be caused by?
- Sudden and involuntary temporary contraction of a muscle
- Believed to be from muscle overuse, holding the position, nerve compression etc.
What is a muscle stitch and what are they thought to be caused by?
- Exercise-related transient abdominal pain (ETAP)
- Believed to be from reduced blood flow, eating/drinking too much before/during exercise
List 6 muscle fibre arrangements
Circular, convergent, multipennate, parallel (including fusiform), unipennate, bipennate
Examples of circular and convergent muscles
- Circular: orbicularis oris, orbicularis oculi
- Convergent: pectoralis major, temporalis in cranium
Examples of unipennate, bipennate and multipennate muscles
- Unipennate: flexors/extensors of the wrist
- Bipennate: rectus femoris
- Multipennate: deltoid, gluteus maximus
Examples of parallel and fusiform muscles
- Parallel: sartorius
- Fusiform: biceps brachii, gastrocnemius
4 functions of the muscular system
Movement of the body, posture and stability, homeostasis, movement of substances
How does the muscular system produce movement of the body
Because actin and myosin contract the sarcomere, then this causes the muscle fibre to shorten, pulling on a tendon. Therefore the tendon pulls on a bone to generate movement
How does the muscular system contribute to stability and posture
Skeletal muscles around our body continuously contract and relax to
maintain balance and an upright posture, whilst sitting and standing
How does the muscular system contribute to homeostasis (thermoregulation)
- skeletal muscles: if cold, shivering (contraction and relaxation of skeletal muscles) occurs to generate metabolic heat. this increases the body temp back to within normal limits
- smooth muscles: arrector pili cause
hairs to stand on end when the body temperature is low, trapping air to decrease heat loss via radiation. This also helps increase the body temperature back to within its normal limits
How does the muscular system allow for movement of substances
- Sphincters (e.g. in the anus and stomach) are made of smooth muscle which contracts or relaxes to open or close the sphincter, hence allowing substances (e.g. faeces or chyme) to move through.
- Smooth muscles in the oesophagus contract and relax behind the bolus of food (peristalsis) to push it down the oesophagus into the stomach
- Skeletal muscle contraction and relaxation (milking action) allows for the movement of lymph
5 ways to ensure a healthy muscular system
- Physical activity to increase muscle strength
- Good diet: protein for muscle development
- Hydration to increase blood flow for nutrient delivery and waste removal
- Sleep to increase rate of recovery
- Warm up/cool down to decrease risk of injury/fatigue
What happens to the muscles after long periods of inactivity?
Because the muscles haven’t been used for an extended period of time, then they are likely to become smaller and weaker = increased risk of atrophy
Ligament/o
Muscul/o
Ligament
Muscle
My/o
Myos/o
Muscle
Ten/o
Tendin/o
Tendon
Sarc/o
Tend/o
Flesh, connective tissue
Tendon
Fibr/o
Aponeur/o
Fibrous tissue, fibers
Aponeurosis
Muscular dystrophy
An inherited disorder characterised by progressive weakness and degeneration of muscle fibres
Myosarcoma
Malignant tumour of the muscles
