Intro Flashcards
4 main functions of muscles
Movement
Body position
Heat
Storing/moving substances
Movement occurs as a result of -
muscular contraction
How do muscles assist in body position?
Continual partila contraction provides posture and balance
What produces heat?
Muscle contraction
What is the process by which muscles produce heat called?
thermogenisis
Thermogenisis contributes to which bodily system essential for homeostasis?
Core temperature
3 examples of how muscles store/move substances
Sphincters - prevent out-flow from hollow organ - stomach/bladder
Contraction/relaxation of smooth muscle in blood vessels helps adjust blood flow
Smooth muscle contractions move food through the gastrointestinal tract, propel urine and push gametes.
4 properties of muscle -
CEEE
Contractability
Excitability - can be triggered by nerve impulses
Extensibility - can stretch without being damaged
Elasticity - returns to original shape after contraction/extension
2 types of muscle - (S)
Striated and non-striated
2 types of striated muscle
Skeletal
cardiac
type of non-striated muscle
smooth
What is skeletal muscle?
VOLUNTARY
attached to bone/cartilage
What is Cardiac muscle
INVOLUNTARY
AUTORYTHMIC
What is smooth muscle
INVOLUNTARY
DO NOT TIRE!
Where can you find smooth muscle?
walls of hollow organs (guts, bladder)
blood vessels
eye (pupil dilation)
Define autorythmic
Contraction without direct nervous stimulation
How is skeletal muscle structured?
Parellel muscle fibres
multi nucleated
How is smooth muscle structured?
Randomly arranged contractile proteins
1 nucleus per cell
A unique feature of cardiac muscle?
Intercalated discs
Muscle cells are known as x or x?
Muscle fibres or myocytes
Which is the longest cell in the body
myocyte
how long is a myocyte?
10-30cm
How are muscle fibres formed?
From the embryonic fusion of myoblasts.
What do muscle fibres lose the ability to do once they are mature?
Undergo Mitosis
Are the number of skeletal muscle fibres each person has set before birth?
yes
Muscle growth, or enlargement of existing fibres is known as -
Hypertrophy
Can muscle cells regenerate?
it is limited. Via Satellite cells.
Flesh/muscle in latin is -
sarco
Mycoctyes or Muscle fibres are made up of many -
Myofibrils
Myofibrils are made up of thick and thin microfilaments or myofilaments called -
Myosin - thick
Actin - thin
A repeating section of Myofibril is called a -
sarcomere
Each Myofibril is covered in -
Sarcoplasmic Reticulum
Sarcoplasmic reticulum stores -
Calcium
tubes extending from the plasma membrane surface into the muscle cell are called -
Transverse Tubules
T Tubules
Muscle cell cytoplasm is known as
sarcoplasm
sarcoplasm is arranged as
Sarcoplasmic Reticulum
Each myofibril is surrounded by
Sarcoplasmic Reticulum
What travel through the sarcolemma and transverse tubules, spreading through muscle to cause contraction?
Action Potentials
In sarcomeres, dark ares where myofilaments overlap are
A bands
in sarcomeres light area of non-overlap are -
I bands
3 connective tissues in and around muscles are -
Epimyseum
Perimysium
Endomysium
Wrapped around entire muscles you will find the -
Epimysium
The epimysium serves as an actor point for
fascia
tendons
ligaments
What is the perimysium
Invagination of Epimyseum around fascicles
Where would you find the Endomyseum
around individual muscle cells
Are the Epimysium, perimysium and Endomysium all connected to each other?
yes (invagination)
what is a motor neuron?
nerve cell
What is a motor end plate?
termination of motor neurons in minute pads on the muscle fibre
The meeting point where a motor end plate meets the muscle fibre is known as -
Neuromuscular junction
The neurotransmitter that bridges the junction gap is -
ACETYLCHOLINE
1 nerve fibre and it’s corresponding muscle fibres is a
motor unit
the strength of a muscle contraction depends on what
the number of motor units in action at a time
What is a motor unit?
1 nerve fibre and its corresponding muscle fibres
3 steps of contraction in SLIDING FILAMENT THEORY
1) Nerve fibre stimulation at the NEUROMUSCULAR JUNcTION
2) ACTION POTENTIAL spreads from nerve, along SARCOLEMMA & T TUBULES into muscle cell releasing Calcium from the SARCOPLASMIC RETICULUM.
3) CALCIUM & ATP trigger MYOSIN to bind to ACTIN to they slide/pull together, shortening fibre = CONTRACTION.
ATP is short for
ADENOSINE TRIPHOSPHATE
3 steps of relaxation in SLIDING FILAMENT THEORY
1) NERVE stimulation stops
2) MAGNESIUM & ATP pumps Calcium back into storage, breaking ACTIN/MYOSIN bond.
3) Actin & Myosin slide back, lengthening fibre = RELAXATION
What effect does Magnesium have on muscle fibres?
Makes them LESS EXCITABLE and prevents MYOSIN binding with ACTIN.
Why would an Epsom salt bath help your muscles to relax?
The Magnesium would stop the Myosin binding with Actin.
What is the theory of how muscles move called?
SLIDING FILAMENT THEORY
Muscle contraction require large amounts of -
ATP
ATP is converted into x and x
energy and heat
metabolism definition
Breakdown of compounds to produce energy (ATP) for bodily functions
Muscles need a good X supply
blood supply
What does blood do for muscles?
provides OXYGEN & NUTRIENTS
removes WASTE
ATP is derived from the breakdown/metabolism of what?
Carbohydrates (glucose)
Fats
Proteins
Shape of SR?
Foam net around each myofibril
Oxygen-binding protein present in Sarcoplasm is called -
myoglobin
Muscles get their oxygen from -
Myoglobin
How many Mitochondria in a Myofibril?
Many
difference between ligament & tendon
tendon binds bone to muscle, ligament binds bone to bone