7/23/2019 Unit 12 the Muscular System

http://slidepdf.com/reader/full/unit-12-the-muscular-system 1/10

UNIT 12: THE MUSCULAR SYSTEM

1. List the three types of musce tissue2. !iffere"ti#te the thee types of musce #ccor$i"% to:

a) Overall shape

b) Presence of striationsc) Nuclei of the muscle celld) Functional characteristicse) Examples within the body

Muscle tissues are highly specialized to contract or shorten to producemovement!

  S&eet# musce: pac"aged by connective tissue sheets into organs called

s"eletal muscles attached to the s"eleton! #an be controlled 'ou"t#riy $orconsciously)

a) %he cells of s"eletal muscle are long cylindrical

b) &triationsc) Multinucleated) 'hen the s"eletal muscles contract they pull on bones or s"in! (s a result gross

body movements or changes in our facial expressions occur! &"eletal musclecells are elongated to provide a long axis for contraction often called musclefibers!

E(MP*E& + (ttached to bones facial muscle or to s"in

  C#r$i#c musce: #ardiac muscle is under i"'ou"t#ry co"tro

a) ,elatively short branching chains of cells that fit tightly together $li"e claspedfingers) at -unctions called intercalated discs

b) &triationsc) .ninucleated) /ntercalated discs contain gap -unctions that allow ions to pass freely from cell

to cell! %his ties the cardiac cells into a functional syncytium $syn 0 together1

cyt 0 cell) resulting in rapid conduction of the exciting electrical impulseacross the heart

E(MP*E&+ 'alls of the heart

7/23/2019 Unit 12 the Muscular System

http://slidepdf.com/reader/full/unit-12-the-muscular-system 2/10

  Smooth ('iscer#) musce:

f) &pindle2shaped pointed at each end single fusiformg) No &triations 3isibleh) .ninucleatei) &lower than the other two muscle types! 'hen walls contract the cavity of an

organ becomes smaller $constricts when smooth muscle contracts) orenlarges $dilates when smooth muscle relaxes) so that substances arepropelled through the organ along a specific pathway! E!g! Peristalsis

E(MP*E&+ Found in the walls of hollow organs such as the stomach uterus andblood vessels!

*. !escri+e the %ross structure of the s&eet# musce #ccor$i"% to:

 

Mem+r#"es:

 Epimysium: overs the entire muscle

 ,erimysium: Form a bundle of fibers called a fascicle E"$omysium: Encloses muscle fiber in a delicate connective tissue sheath

-#scices: 4undle of fibers

7/23/2019 Unit 12 the Muscular System

http://slidepdf.com/reader/full/unit-12-the-muscular-system 3/10

. !escri+e the foo/i"% terms re#ti"% to musces

 

0ri%i" #"$ I"sertio" Siteo 0ri%i" is attached to the immovable or less movable bone

o I"sertio" is attached to the movable bone and when the muscle

contracts the insertion moves toward the origin!

 

Te"$o" $cordli"e)5Apo"eurosis $sheetli"e)o   (ttach muscles indirectly to bones cartilages or connective tissue

coverings!acting to anchor muscles tendons providing durability andconserving space! %endons are mostly tough collagenic fibers so theycan cross rough bony pro-ections which would tear the more delicatemuscle tissues! 4ecause of their relatively small size more ten2 donsthan fleshy muscles can pass over a -oint!

 

urs#

7/23/2019 Unit 12 the Muscular System

http://slidepdf.com/reader/full/unit-12-the-muscular-system 4/10

o urs#e $6purses7) are flattened fibrous sacs lined with synovial

membrane and containing a thin film of synovial fluid! %hey are commonwhere ligaments muscles s"in ten2 dons or bones rub together 

 

Sy"o'i# Mem+r#"e

o  ( sy"o'i# mem+r#"e is the soft tissue found between the

articular capsule $-oint capsule) and the -oint cavityof synovial -oints!

 

Te"$o" She#tho  ( Te"$o" she#th is essentially an elongated bursa that wraps completely

around a tendon sub-ected to friction li"e a bun around a hot dog!

. List the three prim#ry fu"ctio"s of the s&eet# musce (p#%e 13)

o ,ro$uci"% Mo'eme"to M#i"t#i"i"% ,osture #"$ o$y Mo'eme"t

o He#t+ (%P is used to power muscle contraction three28uarters of its

energy escapes as heat! 3ital in maintaining normal body temperature!&"eletal muscle accounts for at least 9: percent of body mass so it is themuscle type most responsible for generating heat

4. !escri+e ho/ the co"tr#ctio" of # s&eet# musce resuts i" themo'eme"t of # +o"e (p#%e 156)

&"eletal muscle contractions pull on tendons which are attached to bones! /fcontraction of the muscle causes the muscle to shorten the bone and thus the

body part will move! For example the biceps brachii is attached to the shoulderand the forearm bones! #ontraction and thus shortening of the biceps brachiipulls on the tendons attached to the bones! &ince the shoulder is stationary theforearm moves! &"eletal muscle contraction however doesn;t always result inthe movement of a body part!

7/23/2019 Unit 12 the Muscular System

http://slidepdf.com/reader/full/unit-12-the-muscular-system 5/10

6. !iffere"ti#te the foo/i"% types of s&eet# musce #s to:o ,rime Mo'er: %he muscle that has the ma-or responsibility for causing

a particular movement

o Sy"er%ist: $ syn 0 together erg 0 wor") help prime movers by

producing the same movement or by reducing undesirable movements

o

A"t#%o"ist: Muscles that oppose or reverse a movement

3. !iffere"ti#te +et/ee" isoto"ic #"$ isometric co"tr#ctio" (p#%e 15)

Isoto"ic co"tr#ctio"s $6same tone7 or tension) the myofilaments are successful in theirsliding movements the musce shorte"s and movement occurs!

Isometric co"tr#ctio"s $ 6same measurement7) the myosin myofilaments are 6spinningtheir wheels7 and the tension in the muscle "eeps increasing! %hey are trying to slidebut the muscle is pitted against some more or less immovable ob-ect!

7/23/2019 Unit 12 the Muscular System

http://slidepdf.com/reader/full/unit-12-the-muscular-system 6/10

7/23/2019 Unit 12 the Muscular System

http://slidepdf.com/reader/full/unit-12-the-muscular-system 7/10

7/23/2019 Unit 12 the Muscular System

http://slidepdf.com/reader/full/unit-12-the-muscular-system 8/10

7/23/2019 Unit 12 the Muscular System

http://slidepdf.com/reader/full/unit-12-the-muscular-system 9/10

7/23/2019 Unit 12 the Muscular System

http://slidepdf.com/reader/full/unit-12-the-muscular-system 10/10