Anatomy unit 5 skeletal and muscular systems sliding filament theory notes

690 views
457 views

Published on

Published in: Education, Business, Technology
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
690
On SlideShare
0
From Embeds
0
Number of Embeds
23
Actions
Shares
0
Downloads
5
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Anatomy unit 5 skeletal and muscular systems sliding filament theory notes

  1. 1. ANATOMY Unit 4 Notes: Sliding Filament Theory
  2. 2. (1) Muscle Contraction • Sliding Filaments = Muscle Contraction • The Basic Steps: 1- Message sent 2- Neurotransmitter 3- Depolarization 4- Calcium + Troponin = Actin Exposed 5- Actin + Myosin (Contraction)
  3. 3. (2) Neuron & Muscle • Cause: – Conscious decision to move – Homeostatic response • Nervous System Sends a Message to the Effector Organ: – Neurotransmitter released (ACh, acetylcholine) – ACh binds to sarcolemma of muscle fiber – ACh initiates opening of sodium-potassium channels
  4. 4. (3) Depolarization • Cause: – Binding of ACh to sodium-potassium channels – Opening of channels + Movement of Na-K+ across sarcolemma • Involves the Movement of Charges: – More Na+ moves in, Than K+ moves out – Imbalance of charges  electrical current (action potential)
  5. 5. (4) Sarcoplasmic Reticulum & Calcium • Cause: Depolarization • Action Potential across the Sarcoplasmic Reticulum causes the release of Calcium: – Ca+ released from membrane of sarcoplasmic reticulum. – Ca+ binds with troponin: • Troponin-Tropomyosion conformation changes • Troponin & Tropomyosin no longer cover Actin • Actin is exposed
  6. 6. (5) Myosin interacts with Actin: • Cause: – Troponin & Tropomyosin unveils Actin – Actin exposed • Myosin releases Inorganic Phosphate + ADP – Pi + ADP = ATP – Myosin changes conformation – Myosin binds to Actin – Myosin and Actin slide towards each other – WE HAVE A CONTRACTION! WOO WOO!
  7. 7. (6) Relaxation • ATP binds back with myosin… –Myosin detaches and moves away from Actin –Troponin & Tropomyosin cover up Actin –Ca+ moves back into Sarcoplasmic Reticulum –Repolarization  Sarcolemma stable again
  8. 8. (7) Why is it called the Sliding Filament Theory? • Movement of myofilaments causes contraction • Myosin grabs actin & SLIDES them towards the center
  9. 9. (1-2) Depolarization of Sarcolemma & Generation of Action Potential (3) Calcium Ions released from Sarcoplasmic Reticulum (4-6) Calcium binds to troponin, tropomyosin moves, actin exposed (7-8) Myosin attaches to actin, Myosin moves actin, ATP released (9) Calcium removed by active transport (10) Everything moves back & contraction done!

×