Metabolisme Otot Dan Tulang

8/10/2019 Metabolisme Otot Dan Tulang

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Metabolismeotot dan tulang[Blok 7: Lokomosi]

Rifana Cholidah



Muscle

a place of many metabolic activities

Three types of muscle: skeletal, cardiac, smooth

The main function: to turn chemical energy intomechanical energy through the breaking down

of ATP Changes in muscle metabolism during prolonged

activities: metabolic rate, relative rate of utilizationof glucose and fatty acids as fuel

Main function as locomotion and heat production,

also to provide protein reserves forgluconeogenesis during fasting



Structure of muscle Contains light (l-band;

isotropic) band anddark (A-band;anisotropic) band

Center of the I-band:darker Z-line

Center of A-band:lighter H-zone with thecentral M-line

Sarcomere: From Z to Z-line

M-line



Continued..

I-band (thin, actin filaments, extendingfrom Z-line)

A-band (thick, myosin filaments,

extending from M-line)Darker straining regions of the A-band: the

region of overlap of actin and myosin



Mucle energy metabolism

Based on ATPase activity and the source ofATP synthesis: anaerobic and aerobic

Mucle types related to muscle function

Striated (skeletal) muscle is divided into:

1. Fast-glycolytic muscle:

White in appearance

Low blood flow Low mitochondrial density

Decreased myoglobin content



2. Fast glycolytic fibers:

o

Increased glycogen storeo Lower fat content

o Depends on glycogen and anaerobicglycolysis for short burst contraction

o Not capable of sustaining long contractionscompared to slow-oxidative fibers

3. Slow-oxidative fibers:

o Well perfused with blood

o Rich in mitochondia and myoglobin

o Ability in sustaining low-intensity contractionfor long periods

o Slow muscle uses fatty acid oxidation for ATPproduction

o The characteristic of cardiac muscle insimilar with slow-oxidative skeletal muscle



Muscle contraction

Membrane ion fluxCalcium release and re-uptake

ATP hydrolysis and synthesis:

Maintenance of ion gradients

Restoration of intracellular Ca levels Actual process of muscle shortening

o Muscle shortening: sarcomere dependson the interaction of filamentous protein,

actin (thin) „n myosin (thick filaments) o Myosin head has ATPase activity

hydrolyzes ATP



Continued…

Thick filaments is made up from myosinprotein

Thin filaments:

Mainly actin

Tropomyosin and troponin family Muscle contraction (shortening)=

ATP is available

Calcium is present

ATP availability depends on:

Synthesis from ADP by the creatinephosphate

Production from aerobic „nanaerobic metabolism



: actin: troponin

: tropomyosin



Energy supplies

1. Short-duration, high intensity contraction: Depends on ATP stores

an additional reserve of the high-energystorage compound (creatine-P) ATPrapidly during the 1st minute as

glycogenolysis is activated During the first stages of exercise:

Muscle glycogenolysis

Followed by both anaerobic and aerobicglycogenolysis as the major source ofenergy

Calcium entry into muscle to formulateCa2+ --calmodilum complex activates

phosphorylase kinase



2. Low intensity, long duration contractions

Availability and utilization of O2 as thelimitation for sustaining continuous PA

Low intensity of PA, O2 is readily available

Aerobic oxidation of lipid is the main source

of ATP synthesis Art the higher work intensities O2 can

become limiting the work rate of the

muscle decreases

Adaptation to regular vigorous PA involves

increasing muscle mass and oxygenation



During the first 15-30 minutes of exercise,there is a gradual shift glycogenolysis and

aerobic glycolysis to aerobic metabolism offatty acids

In many cases, the glycogen reserves inmuscle are sufficient to support the energyneeds of muscle during exercise for about 1

hour

Exercise continues epinephrine activateshepatic gluconeogenesis to provide anexogenous source of glucose for muscle

Lipids gradually become the main source ofenergy in muscle during long-term exercise



3. Long-term muscle performance

Ex: marathon runner

Glycogen is the storage form of glucose in skeletalmuscle

For the sufficient availability of ATP, a continuingbasal level of glycogen and CHO metabolism inmuscle is required

CHO metabolism is important as a source ofpyruvate

Increasing the availability of circulating glucosefrom gluconeogenesis or CHO ingestion

Increased the utilization of fatty acids



Bone



Fungsi tulang

Memberikan rangka tubuh

Melindungi organ-organ vital

Pergerakan

Menjaga keseimbangan elektrolit danasam-basa

Produksi sel darah



Struktur tulang



Bone Metabolism

The factors



A. Hormonal

Vitamin D

Parathyroidhormone

Estrogen

Thyroid hormone

Insulin

B. Nutrisi

Calcium (Ca)

Phosporus(P)

Magnesium

Zinc



Lifestyle Factor Physical activity

Smoking:

Menopause yang lebih awal Penurunan BMD

Alcohol consumption:

Meningkatkan osteoporotic fracture



Calcium

Salah satu mineral yang penting untuk tulang

1200gram pada org dewasa (1-2% BW)

Metabolisme Ca Vit D, calcitonin, & PTH

Bersama dg P, Ca membentuk “insoluble salt”(hydroxyapatite) tulang dan gigi

Kedua mineral ini sangat penting utk bone strength rigiditas dan struktur

Keseimbangan Ca dan P

Ketersediaan Ca:

Dietary Ca

Absorpsi Ca Absorpsi t.u di usus halus, sebagian kecil di colon



Phoshorus



Penting untuk mineralisasi tulang

Kurangnya P dapat menyebabkan

gangguan mineralisasi tulang

80% dari total body P terdapat dijaingan

tulang dan gigi

85% P ditemukan dalam bentuk kristal

hydroxyapatite

P homeostasis sangat dipengaruhi oleh bone

formation



Summary

ATP produced in muscle is important tomaintenance ion gradient, restoration of Ca leveland the contractile process

Fast glycolytic muscle: depends on glycogen and

anaerobic glycolysis for short, high intensity ofmuscle activity

Slow oxidative muscle: anaerobic tissue , uses fatas the main source

During the initial phases, depends on

glycogenolysis and glycolysis, then graduallyconverts to fat metabolism for long-term energyproduction



Thanks

Any questions



New Zealand Spring 2012

Metabolisme Otot Dan Tulang

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