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Location

found in digestive system or respiratory system

Located in the walls of hollow visceral (internal organs)

Structure

Muscle fibers consist of a single nucleus and have no under conscious control

Muscle fibers are cells with a centrally located nucleus. They are connected by a connective tissue (endomysium).

Types

1. Visceral (single unit)- single-shaped sheets of cells, that are located close to each other.

2. Multi-unit smooth muscle- they differ from visceral as the fabers are less organised, and are separate themselves, rather then sheets. (found in irises of the eyes and in the walls of the blood vessels.)

Contraction
Involves reaction of actin and myosin (this is the same reaction that is produced in skeletal muscle contraction)

smooth muscles are affected by two
neurotransmitters, aceticholine and norepinephrin

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Calcium ions and the proteins tropomyosin and troponin control muscle contractions

different processes occur in order for muscle contraction to occur :

1) calcium ion release
2) actin and myosin cross- bridge formation
3) sliding mechanism of actin and myosin filaments
4) sarcomere shortening

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The repeated reorientation of the myosin heads drags the actin filaments along the length of the myosin

As actin filaments are anchored to Z lines, the dragging of actin pulls the Z lines closer together, shortening the sarcomere

As the individual sarcomeres become shorter in length, the muscle fibres as a whole contracts

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The contraction of the skeletal muscle is achieved by the sliding of actin and myosin filaments

•  ATP hydrolysis and cross bridge formation are necessary for the filaments to slide

during muscle contraction  the thin actin filaments slide over the thick myosin filaments

when calcium is present the blocked active site of actin clears.

Step A: Myosin head attaches to actin. (High energy ADP + P configuration)

Step B: Power stroke:  myosin head pivots pulling the actin filament toward the center.

Step C: The cross bridge detaches when a new ATP binds with the myosin.

Step D: Cocking of the myosin head occurs when ATP à  ADP + P. Another cross bridge can form.

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Actin and myopic cross bridge formation 

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Actin and myopic cross bridge formation 

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On actin, the binding sites for the myosin heads are covered by a blocking complex (troponin and tropomyosin)

Calcium ions bind to troponin exposing the binding sites for the myosin heads

The myosin heads then form a cross-bridge with the actin filaments

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Calcium ions are released by the sarcoplasmic reticulum

* muscle contraction are controlled by the actions of calcium

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Structure:
-Forms the contractile wall of the heart

-Striated like skeletal muscle

-Cardiac muscle fibre branch and interconnected via intercalated disk
-Gap junction located in the intercalated disk enable ionic communication and continuity between adjacent cardiac muscle fibres

-Have a single central nucleus
Function:
-Carry out unconscious task: contraction of the heart

-Intercalated disk relay signal from cell to cell and help to synchronize heartbeat.
-Exhibit autorhythmicity and spontaneously generate stimuli

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1)definition:

Muscle tissue is a soft tissue that composes muscles in animal bodies, and gives rise to muscles' ability to contract.

2) components (in general):

Muscle tissue consists of long cells called muscle fibers, which contract in response to nerve signals

This is opposed to other components or tissues in muscle such as tendons or perimysium.

Muscle tissue varies with function and location in the body.

In mammals the three types are:

-skeletal or striated muscle is responsible for voluntary movement

-smooth or non-striated muscle is responsible for involuntary body activities

- cardiac muscle is responsible for contraction of the heart

3)Structures and Functions

Muscle tissue has some important functions, including:

-Movement (both voluntarily and involuntarily)

-Maintaining posture

-Supporting soft tissues within body cavities

-Guarding entrance and exists of the body

-Maintaining body temperature

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Location

found in digestive system or respiratory system

Located in the walls of hollow visceral (internal organs)

Structure

Muscle fibers consist of a single nucleus and have no under conscious control

Muscle fibers are cells with a centrally located nucleus. They are connected by a connective tissue (endomysium).

Types

1. Visceral (single unit)- single-shaped sheets of cells, that are located close to each other.

2. Multi-unit smooth muscle- they differ from visceral as the fabers are less organised, and are separate themselves, rather then sheets. (found in irises of the eyes and in the walls of the blood vessels.)

Contraction
Involves reaction of actin and myosin (this is the same reaction that is produced in skeletal muscle contraction)

smooth muscles are affected by two
neurotransmitters, aceticholine and norepinephrin

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(The ability to stretch and return to the original shape.)

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(The ability to be stretched from the normal resting length.)

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(Responsiveness to stimulation and regulation by nervous impulses and hormones.)

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(The ability to contract or make shorter, when a sufficient stimulus is received.)

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http://www.mhhe.com/biosci/esp/2001_saladin/folder_structure/su/m4/s8/index.htm (muscle characteristics)
https://en.wikipedia.org/wiki/Myofibril (myofibril)
https://www.hccfl.edu/media/569816/10-muscles%20and%20muscle%20tissue.pdf
https://www.hccfl.edu/media/569816/10-muscles%20and%20muscle%20tissue.pdf (smooth tissue)
https://www.slideshare.net/claiddin/muscle-tissue-39881289(Cardiac muscle)

http://ib.bioninja.com.au/higher-level/topic-11-animal-physiology/112-movement/muscle-contraction.html

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Structure:
- consist of bundles of long cell called muscle fibre

-Multiple nuclei located at the edge of the cell

-A single skeletal muscle cell is long and approximately cylindrical in shape
-Myofibril had rod like shape and it is a unit of the muscle cell
-Myofibril is compose of protein such as actin, myosin and titin
-These protein organise into think or thin filament called myofilament that repeat along the length of myofibril in sections called sarcomeres
-arrangement of contractile unit (sarcomeres) along the length of fibre give the cell striped appearance.
-Think myofilament made up of protein myosin. It has rod like shape with 2 round heads at the end called cross bridges
-Thin myofilament made up of protein actin. It consist of double stranded coil and also contain regulatory protein called tropomyosin and troponin.
Function:
-Responsible for voluntary movement

-Provide movement by muscle contraction

-Movement of limb, toe, neck etc.
-Contract and make small adjustment to hold body in stationary position eg. sitting, standing
-Add stability to joints that have poor reinforcement
-Contraction of skeletal muscle produce heat which help to maintain the body temperate