6 Cilia_ Flagella_ Amoeboid Movement_skeletal Muscle Jan 2013 (1)

7/28/2019 6 Cilia_ Flagella_ Amoeboid Movement_skeletal Muscle Jan 2013 (1)

1/162

Topics

1. Introduction

2.Energy and thermodynamics

3.Feeding and digestion

4. Ionic gradient, electrical potential

5.Electrical signals and neurons

6.Cytoskeletons, motor proteins and muscle

7.Heat production and body temperature


2/162

Microtubules and intermediate filaments

http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mcb.chapter.5380
http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mcb.chapter.5380http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mcb.chapter.5380


3/162

What is holding up the

shape of the cell?


4/162

Neurons or

nerve cells


5/162

www.olympusmicro.com


6/162

Cytoskeleton

http://www.youtube.com/watch?v=5rqbmLiSkpk
http://www.youtube.com/watch?v=5rqbmLiSkpkhttp://www.youtube.com/watch?v=5rqbmLiSkpk


7/162

Cytoskeleton and Motor

Proteins

All physiological processes depend on

movement

Intracellular transport Changes in cell shape

Cell motility

Animal locomotion


8/162

Cytoskeleton and Motor

Proteins

All movement is due to the same cellular

machinery

Cytoskeleton

Protein-based intracellular network

Motor proteins

Enzymes that use energy from ATP to move


9/162

Cytoskeleton

COMPONENTS

Ropelike fibers

Long hollowcylinders

Double-strandedhelix

Actin filaments

Intermediate filaments

Microtubules

DesminsKeratin Lamins

Actin Tubulin (/)


10/162Figure 5.1

Use of Cytoskeleton for

Movement Cytoskeleton elements Microtubules

Microfilaments

Three ways to use the

cytoskeleton for movement Cytoskeleton road

(blue) and motor proteincarriers (brown)

To reorganize thecytoskeletal network

Motor proteins pull onthe cytoskeletal rope


11/162

Movement inside the cell

http://www.youtube.com/watch?v=quOoax5RASk&feature=related
http://www.youtube.com/watch?v=quOoax5RASk&feature=relatedhttp://www.youtube.com/watch?v=quOoax5RASk&feature=relatedhttp://www.youtube.com/watch?v=quOoax5RASk&feature=relatedhttp://www.youtube.com/watch?v=quOoax5RASk&feature=relatedhttp://www.youtube.com/watch?v=quOoax5RASk&feature=related


12/162

Microtubules

Are tubelike polymers of the protein tubulin

Similar protein in diverse animal groups

Multiple isoforms

Are anchored at both ends Microtubule-organization center (MTOC) () near

the nucleus

Attached to integral proteins (+) in the plasma

membrane


13/162

Microtubules: Composition and

Formation

Microtubules are polymers of the protein

tubulin

Tubulin is a dimer ofa-tubulin and b-tubulin Microtubule forms spontaneously

For example, does not require an enzyme

Polarity

The two ends of the microtubule are different Minus () end

Plus (+) end

Note: + andhere do not represent charges.


14/162

Microtubules

Figure 5.2


15/162

Microtubule Assembly

Figure 5.4


16/162

+ end


17/162

- end


18/162

Microtubule Assembly

Activation of tubulin monomers by GTP

Monomers join to form tubulin dimer

Dimers form a single-stranded protofilament

Many protofilaments form a sheet

Sheet rolls up to form a tubule

Dimers can be added or removed from the

ends of the tubule Asymmetrical growth

Growth is faster at + end (pure tubulin in laboratory)

Cell regulates rates of growth and shrinkage


19/162

Movement Along Microtubules

Motor proteins move along microtubules Direction is determined by polarity and the

type of motor protein

Kinesin move in (+) direction

Dynein moves in () direction

Movement is fueled by hydrolysis of ATP

Rate of movement is determined by the

ATPase domain of motor protein andregulatory proteins

Dynein is larger than kinesin and moves five

times faster


20/162

How does kinesin work?http://www.youtube.com/watch?v=686qX5yzksU&feature=related
http://www.youtube.com/watch?v=686qX5yzksU&feature=relatedhttp://www.youtube.com/watch?v=686qX5yzksU&feature=related


21/162

Movement of vesicles along microtubules

http://www.youtube.com/watch?v=2-L-Ts6fsks&feature=related
http://www.youtube.com/watch?v=2-L-Ts6fsks&feature=relatedhttp://www.youtube.com/watch?v=2-L-Ts6fsks&feature=relatedhttp://www.youtube.com/watch?v=2-L-Ts6fsks&feature=relatedhttp://www.youtube.com/watch?v=2-L-Ts6fsks&feature=relatedhttp://www.youtube.com/watch?v=2-L-Ts6fsks&feature=relatedhttp://www.youtube.com/watch?v=2-L-Ts6fsks&feature=relatedhttp://www.youtube.com/watch?v=2-L-Ts6fsks&feature=relatedhttp://www.youtube.com/watch?v=2-L-Ts6fsks&feature=relatedhttp://www.youtube.com/watch?v=2-L-Ts6fsks&feature=related


22/162

Vesicle Traffic in a Neuron

Figure 5.7


23/162

Movement of Pigment Granules

Figure 5.3


24/162

Mitosis of a Blood Lily

http://www.youtube.com/watch?v=0oJZDKdperU
http://www.youtube.com/watch?v=0oJZDKdperUhttp://www.youtube.com/watch?v=0oJZDKdperU


25/162

Microtubules and Physiology

Table 5.1


26/162

What if microtubules cant polymerize?

What if microtubules cant depolymerize?


27/162

Applications

Prevent MT breakdown Prevent MT polymerization

Stop cell division

Anti cancerdrugs

Colchicine

Vinblastin

Nocodazole

Taxol

Yew treeColchicum clump


28/162

Cilia and flagella

http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mcb.section.5478

Video

http://www.britannica.com/EBchecked/topic-

video/209268/97516/The-structure-and-movement-of-cilia-and-

flagella
http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mcb.section.5478http://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.britannica.com/EBchecked/topic-video/209268/97516/The-structure-and-movement-of-cilia-and-flagellahttp://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mcb.section.5478


29/162

Cilia and Flagella

Cilia Numerous, wavelike motion

Flagella

Single or in pairs, whip-like movement

Composed of microtubules arranged into

axoneme

Bundle of parallel microtubules

Nine pairs of microtubules around a central pair Nine-plus-two

Asymmetric activation ofdynein causes

movement


30/162

Paramecium movement

http://www.youtube.com/watch?v=Mv0Sfvixeeo

Eating congo red yeast

http://www.youtube.com/watch?v=l9ymaSzcsdY

Contractile vacuole

http://www.youtube.com/watch?v=iG6Dd3COug4&NR=1
http://www.youtube.com/watch?v=Mv0Sfvixeeohttp://www.youtube.com/watch?v=l9ymaSzcsdYhttp://www.youtube.com/watch?v=iG6Dd3COug4&NR=1http://www.youtube.com/watch?v=iG6Dd3COug4&NR=1http://www.youtube.com/watch?v=l9ymaSzcsdYhttp://www.youtube.com/watch?v=Mv0Sfvixeeo


31/162


32/162


33/162


34/162


35/162


36/162

Flagellahttp://www.youtube.com/watch?v=QGAm6hMysTA
http://www.youtube.com/watch?v=QGAm6hMysTAhttp://www.youtube.com/watch?v=QGAm6hMysTA


37/162

Cilia and Flagella


38/162

Where can we find cilia in our bodies?

Oviduct Kidney lobule

Brain ventricle

Lungs

Ear

Intestines


39/162

Cytoskeletal disorders- e.g. motor proteins

Immotile Cilia

Syndrome (Kartagener

syndrome) Dynein

Bronchiectasis,

sinusitis, infertility

Primary Ciliary Dyskinesia Zariwala et al. Gene

Reviews


40/162

Importance of microtubules

Mitosis and meiosis

Flagella and Cilia

Molecular trafficking


41/162


42/162

Microfilaments

Polymers composed of the protein actin

Found in all eukaryotic cells

Often use the motor protein myosin

Movement arises from

Actin polymerization

Sliding filaments using myosin

More common than movement by polymerization

Mi fil t St t d


43/162

Microfilament Structure and

Growth

G-actin monomers polymerize to form a

polymer called F-actin

Spontaneous growth

610 times faster at + end (pure actin in lab cond.)

Treadmilling

Assembly and disassembly occur simultaneously

and overall length is constant

Capping proteins

Increase length by stabilizing end and slowing

disassembly

Mi fil t St t d


44/162

Microfilament Structure and

Growth

Figure 5.9

// / ? 2
http://www.youtube.com/watch?v=xbswna2lIbkhttp://www.youtube.com/watch?v=xbswna2lIbk


45/162

http://www.youtube.com/watch?v=xbswna2lIbk

Treadmilling

Mi fil t (A ti )
http://www.youtube.com/watch?v=xbswna2lIbkhttp://www.youtube.com/watch?v=xbswna2lIbk


46/162

Microfilament (Actin)

Arrangement

Arrangement of microfilaments in the cell

Tangled neworks

Microfilaments linked by filaminprotein

Bundles

Cross-linked by fascinprotein

Networks and bundles of microfilaments are

attached to cell membrane by dystrophinprotein

Maintain cell shape

Can be used for movement


47/162

Mi fil t (A ti )


48/162

Microfilament (Actin)

Arrangement

Figure 5.10

M t b A ti


49/162

Movement by Actin

Polymerization

Two types ofamoeboidmovement

Filapodia are rodlike extensions of cell membrane

Neural connections Microvilli of digestive epithelia

Lamellapodia are sheetlike extensions of cell

membrane

Leukocytes

Macrophages


50/162

Amoeba

A b id t


51/162

Amoeboid movement

http://www.youtube.com/watch?v=gKNzzxuz6uk

Formation of food vacuole

http://www.youtube.com/watch?v=W6rnhiMxtKU
http://www.youtube.com/watch?v=gKNzzxuz6ukhttp://www.youtube.com/watch?v=W6rnhiMxtKUhttp://www.youtube.com/watch?v=W6rnhiMxtKUhttp://www.youtube.com/watch?v=gKNzzxuz6uk


52/162


53/162

Actin Polymerization and Fertilization

Figure 5.11


54/162

Myosin

Most actin-based movements involve themotor protein myosin

Sliding filament model

Myosin is anATPase

Converts energy from ATP to mechanical energy

17 classes of myosin (IXVII)

Multiple isoforms in each class

All isoforms have a similar structure Head (ATPase activity)

Tail (can bind to subcellular components)

Neck (regulation of ATPase)


55/162

Crawling actin

http://www.youtube.com/watch?v=NYmJivEuHes
http://www.youtube.com/watch?v=NYmJivEuHeshttp://www.youtube.com/watch?v=NYmJivEuHes


56/162

Myosin

Figure 5.12


57/162

Animation on myosin-actin generated intracellular transport/movement

http://multimedia.mcb.harvard.edu/anim_myosin.html
http://multimedia.mcb.harvard.edu/anim_myosin.htmlhttp://multimedia.mcb.harvard.edu/anim_myosin.html


58/162

Sliding Filament ModelAnalogous to pulling yourself along a rope

Actin the rope

Myosin your arm

Alternating cycle of grasp, pull, and release

Your hand grasps the rope

Your muscle contracts to pull rope

Your hand releases, extends, and grabs further

along the rope


59/162

Sliding Filament Model Two processes

Chemical reaction

Myosin binds to actin (cross-bridge)

Structural change

Myosin bends (power stroke) Cross-bridge cycle

Formation of cross-bridge, power stroke, release,

and extension

Need ATP to release and reattach to actin Absence of ATP causes rigor mortis

Myosin cannot release actin


60/162

How does myosin workhttp://www.youtube.com/watch?v=VQ4OMSi6qAg&feature=related
http://www.youtube.com/watch?v=VQ4OMSi6qAg&feature=relatedhttp://www.youtube.com/watch?v=VQ4OMSi6qAg&feature=related


61/162

Sliding Filament Model

Figure 5.13


62/162

Actino-Myosin Activity

Two factors affect movement Unitary displacement

Distance myosin steps during each cross-bridge

cycle

Depends on Myosin neck length

Location of binding sites on actin

Helical structure of actin

Duty cycle Cross-bridge time/cross-bridge cycle time

Typically ~0.5

Use of multiple myosin dimers to maintain contact


63/162

Myosin Activity

Figure 5.14


64/162

Actin and Myosin Function

Table 5.2


65/162

Topics

1. Introduction


3.Feeding and digestion4. Ionic gradient, electrical potential





66/162

Muscle

Skeletal muscle structure


67/162

http://www.brookscole.com/chemistry_d/templates/student_resources/shared_res

ources/animations/muscles/muscles.html

http://entochem.tamu.edu/MuscleStrucContractswf/index.html

Muscle contraction and relaxation

http://www.getbodysmart.com/ap/muscletissue/contraction/menu/menu.html

Mechanisms of sliding

http://www.youtube.com/watch?v=BqCj-S6cQgk

http://www.blackwellpublishing.com/matthews/myosin.html

http://www.ebsa.org/npbsn41/intro_muscle.html

http://www.getbodysmart.com/ap/muscletissue/contraction/menu/menu.html

Muscle fatigue

http://sportsmedicine.about.com/od/anatomyandphysiology/a/musclefatigue.htm
http://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/muscles/muscles.htmlhttp://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/muscles/muscles.htmlhttp://entochem.tamu.edu/MuscleStrucContractswf/index.htmlhttp://www.getbodysmart.com/ap/muscletissue/contraction/menu/menu.htmlhttp://www.youtube.com/watch?v=BqCj-S6cQgkhttp://www.blackwellpublishing.com/matthews/myosin.htmlhttp://www.ebsa.org/npbsn41/intro_muscle.htmlhttp://www.getbodysmart.com/ap/muscletissue/contraction/menu/menu.htmlhttp://sportsmedicine.about.com/od/anatomyandphysiology/a/musclefatigue.htmhttp://sportsmedicine.about.com/od/anatomyandphysiology/a/musclefatigue.htmhttp://www.getbodysmart.com/ap/muscletissue/contraction/menu/menu.htmlhttp://www.ebsa.org/npbsn41/intro_muscle.htmlhttp://www.blackwellpublishing.com/matthews/myosin.htmlhttp://www.youtube.com/watch?v=BqCj-S6cQgkhttp://www.youtube.com/watch?v=BqCj-S6cQgkhttp://www.youtube.com/watch?v=BqCj-S6cQgkhttp://www.getbodysmart.com/ap/muscletissue/contraction/menu/menu.htmlhttp://entochem.tamu.edu/MuscleStrucContractswf/index.htmlhttp://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/muscles/muscles.htmlhttp://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/muscles/muscles.html


68/162

htt // t b / t h? TdYN7 PiRI
http://www.youtube.com/watch?v=TdYN7cePiRIhttp://www.youtube.com/watch?v=TdYN7cePiRI


69/162

http://www.youtube.com/watch?v=TdYN7cePiRI

Cramping on stage video
http://www.youtube.com/watch?v=TdYN7cePiRIhttp://www.youtube.com/watch?v=TdYN7cePiRI


70/162

Cramping on stage video

http://www.youtube.com/watch?v=-QSJrjhJUB0&feature=related
http://www.youtube.com/watch?v=-QSJrjhJUB0&feature=relatedhttp://www.youtube.com/watch?v=-QSJrjhJUB0&feature=relatedhttp://www.youtube.com/watch?v=-QSJrjhJUB0&feature=relatedhttp://www.youtube.com/watch?v=-QSJrjhJUB0&feature=related


71/162


72/162

CA2Today 6pm sharp in MPSH (35

min + immediate feedback)

Q&A

PracticalOn blood pressure

homeostasis


73/162

Topics

1. Introduction


3.Feeding and digestion4. Ionic gradient, electrical potential





74/162

Types of muscleBased on

structure and function

Th f M l Ti i l


75/162

Three types of Muscle Tissues in mammals

based on morphological and functional

differences:1. Skeletal Muscle

composed of bundles of very long cylindricalmultinucleated cells that have cross

striations.

Their contraction is quick, forceful and usually

undervoluntary control.


76/162

2. Cardiac Muscle


77/162

2. Cardiac Muscle

composed of elongated or branched individualcells that run parallel to each other.

At sites of end to end contact are theintercalated disks.

Also have cross striations.

Contraction is involuntary, vigorous andrhythmic.

3. Smooth Muscle

consists of collections offusiform cells,no cross striations.

Contraction is slow and involuntary.


78/162


79/162


80/162

Types of skeletal muscle

Based on colorwhite(anaerobic), pink orred

(aerobic)


81/162

Why farmers prefer to plough the land

with a cow instead of a pig?
http://images.google.com/imgres?imgurl=http://www.vegansoapbox.com/wordpress/wp-content/uploads/2008/02/pig.jpg&imgrefurl=http://www.vegansoapbox.com/pigs-like-these/&usg=__zOsD1BRCRD2GOH4otp0RwyZRYFw=&h=345&w=387&sz=33&hl=en&start=2&tbnid=F4Bp_BfnkRj5gM:&tbnh=110&tbnw=123&prev=/images%3Fq%3Dpigs%26gbv%3D2%26hl%3Den%26sa%3DG


82/162

There are different types of muscle with different

ATPase activity and differing speeds of contraction :


83/162

ATPase activity and differing speeds of contraction :Fast Muscle

low oxidation

Fast Muscle

high oxidation

Slow Muscle

high oxidation

1. 2. 3.

very low

mitochondria

Many mitochondria Many

mitochondria

white or pink, few

oxidative enzymes no

myoglobin

darker pink oxidative

enzymes low myoglobin

dark red oxidative

enzymes high

myoglobin

uses only glucose uses glucose, fat

and protein

uses glucose, fat

and protein

easily fatigued

lactic acid formed

easily fatigued

lactic acid formed

long lasting little

lactic acid

Fast ATPase Intermediate

ATPase

Slow ATPase

Tetanus

tensions

a)

b)

c)

d)

e)

f)

time

Tension Tension

time time

Tension


84/162

Wh f f t l h th l d


85/162

Why farmers prefer to plough the land

with a cow instead of a pig?
http://images.google.com/imgres?imgurl=http://www.vegansoapbox.com/wordpress/wp-content/uploads/2008/02/pig.jpg&imgrefurl=http://www.vegansoapbox.com/pigs-like-these/&usg=__zOsD1BRCRD2GOH4otp0RwyZRYFw=&h=345&w=387&sz=33&hl=en&start=2&tbnid=F4Bp_BfnkRj5gM:&tbnh=110&tbnw=123&prev=/images%3Fq%3Dpigs%26gbv%3D2%26hl%3Den%26sa%3DG


86/162

http://images.google.com/imgres?imgurl=http://www.thebetterweigh.com/images/

marathoner sprinter2 jpg&imgrefurl=http://www thebetterweigh com/exercise html


87/162

marathoner_sprinter2.jpg&imgrefurl http://www.thebetterweigh.com/exercise.html

&usg=__x1tyA1ragf6OtF5-

KoaIIwelpsY=&h=376&w=361&sz=19&hl=en&start=3&tbnid=9z_vv4-

T2wVNFM:&tbnh=122&tbnw=117&prev=/images%3Fq%3Dsprinter%26gbv%3D2

%26hl%3Den


88/162

Skeletal muscle


89/162

http://www.youtube.com/watch?v=KG1JHW_q2VA
http://www.youtube.com/watch?v=KG1JHW_q2VAhttp://www.youtube.com/watch?v=KG1JHW_q2VA


90/162

What constitute the thickfilaments?

What is the function of themyosin head?


91/162

HMM

S1

LMM

HMM

S2


92/162

What constitute the thin

filaments?

What is the function of the G-

actin and F-actin?


93/162


94/162

Sarcomeres


95/162

Sarcomeres Thin and thick filaments overlap in two

regions of each sarcomere

Each thick filament is surrounded by six thin

filaments

Three-dimensional organization of thin andthick filaments is maintained by other proteins

Nebulin

Along length of thin filament

Titin

Keeps thick filament centered in sarcomere

Attaches thick filament to Z-disk

Sarcomeres


96/162

Sarcomeres

Figure 5.17

Three-Dimensional Structure of


97/162

Sarcomere

Figure 5.18


98/162

What are the advantages ofhaving many units of short

sarcomeres instead ofone long

units which covers the whole

length of the muscle?


99/162


100/162

ARRANGEMENT OF THICK AND


101/162

THIN FILAMENTS

At Z line, thin filaments do not run straight through, but

terminate.

The thin filaments of 2 adjacent sarcomeres show a

polarity which can be observed by interacting them with

isolated myosin heads which decorate the thin

filaments at specific angles.


102/162


103/162

Why would the muscle exhibit constant

volume contraction?


104/162

Since skeletal muscle is

voluntary, how is skeletal

muscle contractioncontrolled?


105/162


106/162

What is the role of calcium in musclecontraction?

How does it work together with troponinand affect tropomyocin?


107/162

(Dihydropyridinereceptor )


108/162


109/162

How does sliding occur between thick

and thin filaments?


110/162


111/162

Video on control of muscle contraction
http://www.youtube.com/watch?v=WRxsOMenNQM


112/162

http://www.youtube.com/watch?v=WRxsOMenNQM
http://www.youtube.com/watch?v=WRxsOMenNQMhttp://www.youtube.com/watch?v=WRxsOMenNQM


113/162

During shortening of the sarcomere,

there are no changes in the lengths

of the think and thin filaments.


114/162


115/162

What are the roles of ATP in muscle

contraction?

Structure of ATP


116/162

The bonds between the phosphate groups of ATP

are unstable and can be broken by hydrolysis.


117/162


118/162

If no ATP is available

to bind to the myosin

head, the actiomyosin

complex will not

dissociationRigor

Mortis after death


119/162

So, what are the roles of ATP in the

contraction and relaxationof skeletalmuscle contraction?

Myosin head conformational change

Dissociation of actomyosin complex

Active transport of Ca++

Maintenance of Na+ and K+ gradients


120/162

What is the relationship between the

degree of overlap between thick and thin

filaments and the tension build up?


121/162

Thi t k l t t t l


122/162

This process takes place at constant muscle

volume, thus as the sarcomeres shorten, thespacing between filaments increases

accordingly. As tension develops, this tension

is equal or nearly so, in all sarcomeres. The

tension developed in each cross-bridging

adds to the others within the sarcomere. Thus,

the total tension which can be developed

varies with the degree of overlap between

thick and thin filaments.


123/162

How should you position your shoulder,


124/162

y p y

arm and forearm at the start of an arm-

wrestling event?


125/162

What is a muscle twitch,and what is

tetany (muscle cramp)?


126/162

The mechanical response of a muscle fiber to a

single action potential is known as a twitch.


127/162


128/162


129/162

A maintained contraction in response to repetitive

stimulation is known as a tetanus.

Reading assignment on muscle cramp:


130/162

http://www.medicinenet.com/muscle_cramps/article.htm

Muscle cramp (tetany)
http://www.medicinenet.com/muscle_cramps/article.htmhttp://www.medicinenet.com/muscle_cramps/article.htm


131/162

Tetanus disease Clostr id ium tetani


132/162

Summary: Muscle structure and functionhttp://www.youtube.com/watch?v=ren_IQPOhJc
http://www.youtube.com/watch?v=ren_IQPOhJchttp://www.youtube.com/watch?v=ren_IQPOhJc


133/162

Topics


134/162

1. Introduction








135/162

What is a motor unit?

Is it good to have large motor units orsmall motor units?


136/162

Neuromuscular junction and motor unit:

http://www.youtube.com/watch?v=hzXVe4RS8-A(8:50min).

The details of muscle contraction:

http://www.youtube.com/watch?v=f0mDFP7qn1Y&feature=relate

d

Size of motor unitsdelicate or powerful

movement?
http://www.youtube.com/watch?v=hzXVe4RS8-Ahttp://www.youtube.com/watch?v=f0mDFP7qn1Y&feature=relatedhttp://www.youtube.com/watch?v=f0mDFP7qn1Y&feature=relatedhttp://www.youtube.com/watch?v=f0mDFP7qn1Y&feature=relatedhttp://www.youtube.com/watch?v=f0mDFP7qn1Y&feature=relatedhttp://www.youtube.com/watch?v=hzXVe4RS8-Ahttp://www.youtube.com/watch?v=hzXVe4RS8-Ahttp://www.youtube.com/watch?v=hzXVe4RS8-A


137/162

movement?


138/162


139/162


140/162


141/162

Th t t i l fi i


142/162

The motor neurons to a given muscle fire in an

asynchronous pattern.Thus some motor units will be contracting while

others are relaxing.

This asynchrony has the advantages of:

1. Preventing fatigue of the muscle.

Some units are resting at all times.

2. Maintaining a nearly constant tension in the


143/162

muscle. If all were firing in synchrony,

movement would be jerky series ofcontractions and relaxations. This type of

movements is associated with certain

diseases such as Parkinsons disease andalso the normal shivering responses to cold.

Both inhibition of the subcortical centers in

the dominated by local feed back loops fromstretch receptors which tend to become

synchronous and thus oscillatory.

Parkinsons disease and stem cell research

http://www.youtube.com/watch?v=1yCgLythe00
http://www.youtube.com/watch?v=1yCgLythe00http://www.youtube.com/watch?v=1yCgLythe00


144/162

Giving feedback


145/162

Teacher givesimmediate feedbackto learners aftereliciting responses.

Regular feedbackenhances learning.

Teacher has

opportunity toreinforce and correctthe performances

11. During the formation of an action potential, the


146/162

g p

reploarization of Vm occurs by ______________.

A) the opening of sodium activation gates

B) an increase in the membrane's permeability to

potassium and chloride ions

C) the delay in the action of the sodium-potassium pump

D) the opening of voltage-sensitive potassium channels

and the closing of sodium inactivation gates

E) the refractory period in which the membrane is

hyperpolarized

32 If the concentration of K+ concentration in the


147/162

32. If the concentration of K concentration in the

cytoplasm of a nerve cell with a resting membrane

potential of -70 mV were elevated above normal, thenew resting potential would _______.

A) still be -70 mV

B) be -69 mV or higherC) be -71 mV or lower

D) be 0 mV

E) reverse polarity

Topics


148/162

1. Introduction







What happens to your muscles


149/162


as youaged?

http://images.google.com/imgres?imgurl=http://www.fall-prevention-institute.org/images/wastedleg.jpg&imgrefurl=http://www.fall-prevention-

institute.org/muscleloss.html&usg=__YLSBli2KA1mda24Ysp9Y8uQyzMc=&h=332&w=295&

sz=14&hl=en&start=2&tbnid=3PMOg_PwX_Z_dM:&tbnh=119&tbnw=106&prev=/images%3F

q%3Daging%2Bmuscle%26gbv%3D2%26hl%3Den


150/162


151/162


152/162


153/162


as youaged?

Do exercise!!!

EXERCISE AND MUSCLES


154/162

Moderate exercise increases the diameter of musclecells, thus enlarging and strengthening the gross

muscle being exercised.

If the exercise involves movement, as in weight

lifting. It is said to beisotonic, for though a muscle

does shorten during such exercise, its tension does

not greatly increase. If one exercise, by pushing

against an immovable object, or by opposingantagonistic muscle to each other, the resulting

contraction does not actually shorten the muscle.

This is calledisometric exercise.

Although muscle fibers enlarge with body growth,

they do not increase in number so that as they


155/162

they do not increase in number, so that as they

die they cannot be replaced (under normalcircumstances). However, vigorous and continual

exercise may lead to hypertrophy (i.e. increase in

myofibril number). Thus, without exercise, the number of muscle

cells in all muscles drastically decreases in old

age. Part of this decrease is no doubt due to minor

injuries that occur in the course of a life time.

Isometric Isotonic


156/162

Isometric

contraction

Isotonic

contraction


157/162


158/162


159/162

Isometric


160/162

contraction

Muscle soreness and injury

http://www.youtube.com/watch?v=cy15viNaZVw
http://www.youtube.com/watch?v=cy15viNaZVwhttp://www.youtube.com/watch?v=cy15viNaZVw


161/162


162/162

End

Documents

6 Cilia_ Flagella_ Amoeboid Movement_skeletal Muscle Jan 2013 (1)