Tiga jenis otot utama yakni otot rangka, jantung, dan licin. Otot rangka bersel silinder panjang berbbrp inti dengan striasi dan kontraksi sukarela cepat. Otot jantung bersel cabang dengan 1-2 inti, striasi, dan kontraksi tak sukarela sedang. Otot licin bersel memanjang tanpa striasi dan kontraksi tak sukarela lambat.
macam macam otot rangka dan cara kerja otot rangka ciri-ciri otot rangka serta penggunaan energi ATP dalam proses kerja otot, struktur otot rangka dimulai dari makrosize hingga mikrosize.diperuntukan untuk siswa ataupun mahasiswa dalam mengerjakan soal-soal yang terkait dengan masalah otot rangka.
Prinsip dasar biomolekul adalah peran dan interaksi molekul-molekul hayati dalam mengontrol reaksi-reaksi biologis.
Interaksi tersebut berlangsung di dalam sel (intrasel) maupun di luar sel (ekstasel) makhluk hidup.
Inti reaksi biologis tersebut adalah berupa reaksi metabolisme pembentuk senyawa (anabolisme) atau penguraian senyawa (katabolisme) dengan bantuan enzim-enzim tertentu.
Bahan dasar metabolisme tersebut diperoleh dari makromolekul yang tekandung dalam makanan yaitu karbohidrat, lemak, dan protein.
Asam nukleat berperan dalam meregulasi reaksi metabolisme tubuh seperti proses pemeliharaan, transmisi, dan ekspresi informasi hayati yang meliputi replikasi, transkripsi, dan translasi.
Komponen ini disusun oleh 3 unsur utama, yaitu karbon (C), hidrogen (H) dan oksigen (O).
Jenis-jenis karbohidrat sangat beragam dan mereka dibedakan satu dengan yang lain berdasarkan susunan atom-atomnya, panjang/pendeknya rantai serta jenis ikatan akan membedakan karbohidrat yang satu dengan lain.
Dari kompleksitas strukturnya dikenal kelompok karbohidrat sederhana (seperti monosakarida dan disakarida) dan karbohidrat dengan struktur yang kompleks atau polisakarida (seperti pati, glikogen, selulosa dan hemiselulosa).
Sebuah buku foto yang berjudul Lensa Kampung Ondel-Ondelferrydmn1999
Indonesia, negara kepulauan yang kaya akan keragaman budaya, suku, dan tradisi, memiliki Jakarta sebagai pusat kebudayaan yang dinamis dan unik. Salah satu kesenian tradisional yang ikonik dan identik dengan Jakarta adalah ondel-ondel, boneka raksasa yang biasanya tampil berpasangan, terdiri dari laki-laki dan perempuan. Ondel-ondel awalnya dianggap sebagai simbol budaya sakral dan memainkan peran penting dalam ritual budaya masyarakat Betawi untuk menolak bala atau nasib buruk. Namun, seiring dengan bergulirnya waktu dan perubahan zaman, makna sakral ondel-ondel perlahan memudar dan berubah menjadi sesuatu yang kurang bernilai. Kini, ondel-ondel lebih sering digunakan sebagai hiasan atau sebagai sarana untuk mencari penghasilan. Buku foto Lensa Kampung Ondel-Ondel berfokus pada Keluarga Mulyadi, yang menghadapi tantangan untuk menjaga tradisi pembuatan ondel-ondel warisan leluhur di tengah keterbatasan ekonomi yang ada. Melalui foto cerita, foto feature dan foto jurnalistik buku ini menggambarkan usaha Keluarga Mulyadi untuk menjaga tradisi pembuatan ondel-ondel sambil menghadapi dilema dalam mempertahankan makna budaya di tengah perubahan makna dan keterbatasan ekonomi keluarganya. Buku foto ini dapat menggambarkan tentang bagaimana keluarga tersebut berjuang untuk menjaga warisan budaya mereka di tengah arus modernisasi.
7. • Tiap serabut otot terdiri dari ribuan
myofibril
• Tiap myofibril terdapat 1500 filamen
meosin dan 3000 filamen aktin
• Tiap filamen meosin terdiri dari molekul
meosin BM 33.200 dan molekul aktin
BM 70.000
8. • Dengan mikroskup cahaya : nampak
gambaran gelap terang kepadatan
relatif dan ada bagian yang tumpah
tindih dr aktin dan miosin
9. Pita cahaya I
• Terdiri filamen aktin saja (nampak terang)
• Sifat terhadap cahaya yg terpolarisasi
(berkas cahaya yg datang dipancarkan ke
semua jurusan krn kepadatan sama)
I band
10. Pita A
• Terletak dimana aktin dan meosin
tumpang tindih (shg nampak gelap)
• Sifat anisotropik (cahaya dipancarkan
tdk merata)
A band
11. Sarkomer
• Terbentuk oleh 2 garis Z (protein
nonkontraktil) atau sebuah pita A dan 2
belahan pita I
Sarkoplasma
• Sitoplasma sel2 otot
• Terdapat retikulum sarkopasma agranuler
17. • Active site : suatu molekul ADP dimana
filamen meosin saling mengadakan interaksi
dgn filamen aktin shg terjadi kontraksi otot
• Tropomeosin : merupakan protein yg akan
“menutupi” active site shg tdk terjadi kontraksi
• Troponin : akan berikatan dgn Ca utk
permulaan kontraksi
21. Sarcomere Completely
Contracted
Kontraksi yg sempurna menyebabkan pita H tidak nampak,
pita I pendek sekali
22. Ilustrasi relaksasi dan kontraksi otot
Terlihat bahwa filamen meosin tidak berubah,
yg bergerak adalah aktin
23. Teori kontraksi
otot:
• Ion Ca akan aktifkan
filamen aktin
• Kepala meosin akan
terikat pd active site
filamen aktin, akan
dihasilkan energi
• Kepala jadi miring ke
pertengahan meosin
(disebut power
stroke)
24. • Kmdn secara otomatis
kepala dilepaskan dr
active site kembali
tegak lurus
• Kmdn berikatan dgn
active site berikutnya,
kmdn miring (power
stroke) sehingga
filamen aktin bergerak
• Begitu seterusnya
langkah demi langkah
tarik filamen aktin ke
pertengahan meosin
30. Mekanisme umum
kontraksi otot
• Potensial aksi berjalan di
sepanjang saraf motorik
sampai ujungnya pada
saraf otot
• Pada setiap ujung saraf
mensekresi neurotransmitter
(y.i asetilkolin) dlm jumlah
sedikit.
• Asetilkolin bekerja pd
membran serabt otot dan
akan membuka saluran
bergerbang asetilkolin
31. • Terbukanya saluran asetilkolin
memungkinkan ion Na mengalir ke bag.
dalam membran serabut otot pada titik
terminal saraf sehingga timbul potensial
aksi dalm serabut otot.
• Potensial aksi berjalan di sepanjang
membran serabut otot shg sbabkan
retikulum sarkoplasma lepaskan ion Ca.
32. • ion Ca akan berikatan dgn troponin utk
memulai terjadi kontraksi
• Kepala meosin berikatan dgn active site dan
terjadi power stroke (lihat teori kontraksi !!)
• Setelah kurang dr 1 detik ion Ca dipompa ke
dalam retikulum endoplasma (disimpan
sampai potensial aksi yang baru datang lagi)
sehingga kontraksi berhenti
35. Muscle Fatique/kelelahan otot
• Tidak adanya oksigen sehingga ATP yg
dihasilkan sedikit
• Respirasi anaerob menyebabkan terbentuk
asam laktat (terasa pegal)
36. Muscle Atrophy
• Mengecilnya ukuran otot
• Dapat disebabkan karena :
3. Immobilization
4. Loss of neural stimulation
37. Muscle Hypertrophy
• Peningkatan ukuran sel otot
• Banyak kapiler
• Banyak mitochondria
• Dapat disebabkan karena :
– Sering latihan
– Steroid hormones
This is the presentation for Muscle Physiology for Human Anatomy and Physiology II at Oklahoma City Community College.
There are three types of muscle tissue in the body. Skeletal muscle is the type that attaches to our bones and is used for movement and maintaining posture. Cardiac muscle is only found in the heart. It pumps blood. Smooth muscle is found in organs of the body such as the GI tract. Smooth muscle in the GI tract moves food and its digested products.
Skeletal muscle attaches to our skeleton. *The muscle cells a long and cylindrical. *Each muscle cell has many nuclei. *Skeletal muscle tissue is striated. It has tiny bands that run across the muscle cells. *Skeletal muscle is voluntary. We can move them when we want to. *Skeletal muscle is capable of rapid contractions. It is the most rapid of the muscle types.
Cardiac muscle tissue is only found in the heart. *Cardiac cells are arranged in a branching pattern. * Only one or two nuclei are present each cardiac cell. *Like skeletal muscle, cardiac muscle is striated. *Cardiac muscle is involuntary. *Its speed of contraction is not as fast as skeletal, but faster than that of smooth muscle.
Smooth muscle is found in the walls of hollow organs. *Their muscle cells are fusiform in shape. *Smooth muscle cells have just on nucleus per cell. *Smooth muscle is nonstriated. *Smooth muscle is involuntary. *The contractions of smooth muscle are slow and wave-like.
In this unit we will primarily study skeletal muscle. Each muscle cell is called a muscle fiber. Within each muscle fiber are many myofibrils.
A small section of a myofibril is illustrated here. Note the thick myosin filaments are arranged between overlapping actin filaments. *The two Z lines mark the boundary of a sarcomere. The sarcomere is the functional unit of a muscle cell .We will examine how sarcomeres function to help us better understand how muscles work.
Dark and light bands can be seen in the muscle fiber and also in the smaller myofibrils. An enlargement of the myofibril reveals that they are made of smaller filaments or myofilaments. *There is a thick filament called myosin and *a thin filament called actin. Note the I band, A band H zone or band and Z disc or line. These will be discussed shortly.
A myosin molecule is elongated with an enlarged head at the end.
Many myosin molecules form the thick myosin filament. It has many heads projecting away from the main molecule.
The thinner actin filament is composed of three parts: actin, tropomyosin and troponin.
Here is a sarcomere illustrating the thin actin and thick myosin filaments. The area of the sarcomere has only myosin is called the H band.
Here is another diagram of a sarcomere. Note the A band. It is formed by both myosin and actin filaments. The part of the sarcomere with only actin filaments is called the I band. This is a sarcomere that is relaxed.
This sarcomere is partially contracted. Notice than the I bands are getting shorter.
The sarcomere is completely contracted in this slide. The I and H bands have almost disappeared.
Which filament has moved as the sarcomere contracted? Note the thick myosin filaments have not changed, but the thin actin filaments have moved closer together.
The string of green circles represents an actin filament. There are binding sites in the filament for the attachment of myosin heads. *In a relaxed muscle the binding sites are covered by tropomyosin. The tropomyosin has molecules of troponin attached to it. *Calcium, shown in yellow, will attach to troponin. *Calcium will change the position of the troponin, tropomyosin complex. *The troponin, tropomyosin complex has now moved so that the binding sites are longer covered by the troponin, tropomyosin complex.
The binding sites are now exposed and myosin heads are able to attach to form cross bridges.*
The next few slides will summarize the events of a muscle contraction. The nerve impulse reaches the neuromuscular junction (myoneural junction).
This diagram shows the microanatomy of skeletal muscle tissue again. *The blue sarcoplasmic reticulum is actually the endoplasmic reticulum. It stores calcium. *The mitochondria are illustrated in orange. They generate ATP, which provides the energy for muscle contractions.
Acetylcholine is released from the motor neuron.
The influx of sodium will create an action potential in the sarcolemma. Note: This is the same mechanism for generating action potentials for the nerve impulse. The action potential travels down a T tubule. As the action potential passes through the sarcoplamic reticulum it stimulates the release of calcium ions. Calcium binds with troponin to move tropomyosin and expose the binding sites. Myosin heads attach to the binding sites of the actin filament and create a power stroke. ATP detaches the myosin heads and energizes them for another contraction. The process will continue until the action potentials cease. Without action potentials the calcium ions will return to the sarcoplasmic reticulum.
A motor unit is all the muscle cells controlled by one nerve cell. This diagram represents two motor units. Motor unit one illustrates two muscle cells controlled by one nerve cell. When the nerve sends a message it will cause both muscle cells to contract. Motor unit two has three muscle cells innervated by one nerve cell.
Muscle fatigue is often due to a lack of oxygen that causes ATP deficit. Lactic acid builds up from anaerobic respiration in the absence of oxygen. Lactic acid fatigues the muscle.
Muscle atrophy is a weakening and shrinking of a muscle. It can be caused by immobilization or loss of neural stimulation.
Hypertrophy is the enlargement of a muscle. Hypertrophied muscles have more capillaries and more mitochondria to help them generate more energy. Strenuous exercise and steroid hormones can induce muscle hypertrophy. Since men produce more steroid hormones than women, they usually have more hypertrophied muscles.
Steroid hormones such as testosterone stimulate muscle growth and hypertrophy.
Muscle tonus or muscle tone refers to the tightness of a muscle. In a muscle some fibers are always contracted to add tension or tone to the muscle.
Tetany is a sustained contraction of a muscle. It results from a rapid succession of nerve impulses delivered to the muscle.
This concludes the presentation on Muscle Physiology