Muscle Flashcards
Functions,structures
Functions of muscle tissues
To produce force Cause emotion Heat generation Locomotion/movement Joint stabilization
Types of muscle tissues?
Skeletal
Cardiac
Smooth
Location of Smooth muscles
Inner linings of organs
Location of skeletal
Attached to bones
Location of Cardiac muscles
In the heart
Longest group of cells
Structure of skeletal
Long Cylindrical Multinucleated Striated Peripherally placed nuclei
Functions of skeletal
Voluntary actions
Locomotion
Facial expressions
Structure of cardiac muscle
Striated
Elongated
Unicleated cells and branched
Intercalated discs
Structure of smooth muscle
Spindle shaped Central nuclei Unstriated Arranged closely Irregularly arranged
Aim of contractility characteristics?
To shorten
Because shortening generates pulling strength
What does excitability characteristics do?
Nerve fibers causes electrical impulses to travel
What does it mean for the characteristics of extensibility?
Stretch with contraction of an opposing muscle
What does elasticity characteristics mean?
The muscle recoils passively after being stretched
Contraction of skeletal muscle?
Quick and vigorous
Contraction of cardiac?
Vigorous and rhythmic
Contraction of smooth m?
Slow and long lasting
The membrane that covers nerve fibres?
Endomysium
Grouped fibers?
Fassicles
The membrane that covers flassices?
Perimysium
The membrane that covers the muscle?
Epimysium
Skeletal fibers can be deferentiate into?
Red fibers and white/intermediate fibers
Diameter and mitochondria of white and red fibers?
Red fibers:
Small diameter
More mitochondria
white fibers:
Large diameter
Less mitochondria
Red fibers make up which muscles?
Slow-twitch muscles for endurance
Red fibers make up which muscles?
Slow-twitch muscles for endurance
White fibers make up which muscles?
Fast-twitch muscle(burst of power)!
Which fibers are more resistant to fatigue?
Red fibers
Which fibers have more myoglobin?
Red fibers
Which fibers store glycogen and use anaerobic metabolism?
White fibers
Which muscle have 1 or 2 centrally placed nuclei?
Cardiac muscle
How are T tubules in a cardiac muscle?
They are 2X larger in diameter than in skeletal muscle
Function of T tubules?
Transport Calcium ions into fibers
Describe fibers in cardiac muscle
Branched with Intercalated discs
The muscle fiber is known as?
Myocyte
A longitudinal bundle of myofilamenfs within a muscle Cell?
Myofibrils
Which type of muscles contain actin and myosin
All of them
Myofilaments is made up of what?
3 types of filaments
Myosin-thick
Actin-Thin
Titin-Elastic
Which muscles have sarcomeres?
The striated ones..
Cardiac and skeletal muscles
What is a sarcomeres?
Segment that runs from Z line to Z line
Characteristics of smooth muscle
Cells are spindle shaped with central nucleus
Not striated
Contain more actin than myosin
No sarcomeres
Prominent presence of dense bodies instead of Z disks
Mechanism of smooth muscle contraction
Intracellular calcium ions concentrations increase when Calcium enters the cell and release from sarcoplasmic reticulum
Calcium ions bonds to calmodulin
The calcium ions-calmodulin activates MLCK
MLCK phosphorylates light chains in myosin heads and increases myosin ATPase activity
Active myosin crossvridges side along chain and create muscle tension
The relaxation mechanisms of muscle tissues
free calcium ions in cytosol decreases when Calcium is pumped out of the cell or back into the sarcoplasmic reticulum
Calcium ions unbinds from calmodium
Myosin phosphatase removes phosphate from myosin which decreases myosin ATPase activity
Less myosin ATPase results in decreased muscle tension
Myosin ATPase activity in different muscles
Faster in skeletal
Slowest in smooth
Intermediate in cardiac
