Sunday, August 13, 2017

Locomotion and Movement part 1 notes (Biology)


All locomotions are movement but all movement not locomotion.
Types of movement:-
1) Pseudopodial/ amoeboid:- cyclosis (streaming movement of cytoplasm) e.g. Macrophage.
 2) Ciliary:- e.g. Trachea and fallopian tubes.
3) Flaggelar:- e.g. Sperm 
4) Muscular:-e.g. All body part movement.
Skeletal Muscles:- 
  • These are voluntary muscles.
  • Fascia is covering of connective tissue present beneath skin surrounding entire muscle.
  • Muscle is made up of bundles of musle cells called fascicle covered by perimysium.
  • Many such bundles are covered with epimysium.
  • Skeletal muscles are syncitial i.e. multinucliated due to fusion of cells.
  • It shows light and dark bands therefore called striated.
  • Endoplasmic reticulam is called sarcoplasmic reticulum which stores calcium with protein calsequestrin.
  • Plasma membrane is sarcolemma covered by endomysium.
  • Invaginations in plasma membrane are called T-tubules(Transverse tubules) which help in spreading signal deep inside muscle. It is found near line and sarcoplasmic reticulum.
  • Muscle is made up of two types of myofilaments/ myofibrils present in parllely arranged sarcomere.
  Two contractile protein are  Actin and Myosin:-
Actin:-
  • Light filament.
  • Polymer of Globular actin( G- actin)
  • G-actin joins to form F-actin (Filament actin).
  • Two such filaments coil together to form Actin.
  • Each F-actin has its own filament of tropomysin (Regulatory protein).
  • All regular interval Troponin (Regulatory protein) madre up of 3 subunits are found.
  • Three subunits of troponin:- 
  1. Troponin for inhibition. 
  2. Troponin for Tropomyosin.
  3. Troponin for calcium.
  • Each G-actin has myosin binding site which is covered by tropomyosin and troponin at regular interval.
  • Actin is surrounded by three myosin.
  • One end of actin is free, other joined to the membrane .
  • Diametre = 50 A.
  • It forms light band.
Myosin:-
  • Heavy filament.
  • Polymer of meromyosin-II.
  • Meromyosn has two parts 
  1. Heavy meromyosin(HMM)
  2. Light meromyosin (LMM)
  •  Head has actin binding site at tip and ATP binding site at sides.
  • Centre of head has ATPase activity.
  • Diametre-100A.
  • Free at both ends.
  • Present in centre of sacomere.
  • Each myosin is surrounded by 6 actin.
  • Forms dark band.
 Sliding Filament Theory for muscle contraction:-
  • Given by Huxley and Huxley.
  • Supported by Niedergerk and Hanson.
  • ATP binds to head of myosin.
  • ATPase activity of myosin converts ATP into ADP + Pi. This requires magnesium.
  • Myosin forms cross bridge with Actin and swirls towards centre of sacomere.
  • Actin filament slides over myosin causing contraction of sarcomere thus muscle.
  • Calcium comes out from SR and binds to troponin. This removes tropomyosin and troponin complex away from myosin binding site of Actin.
  • Myosin can now easily bind actin.
Relaxation of muscle:-
  • Relaxation of muscle also require ATP.
  • Whe new ATP binds to myosin ATP and Pi is removed. This shifts myosin back to its original site and sarcomere relaxes.
  • Entry of calcium back into SR is against concentration gradient. Therefore active transport also requires ATP.
A-band - Anisotropic
I-band - Isotropic 
H-band - Hanson`s
Z-line - memb. of Krauz.
M-line - Middle line 
  • A-band never changes its size.
  • I and H-band reduces.
 Motor unit - one neuron plus all muscle cells forms one motor unit. A muscle is made up of many motor units.

Muscle Twitch- Sudden spontaneous contraction followed by relaxation. It is found only in laboratory.

Muscle Tetanization-Sequential recruitment of motor units to maintain contraction.

Muscle Tone- A very low level and sustained contraction of our back muscle to maintain posture.

All or non phenomena-There is a minimum threshold value of neurotransmitters required for muscle to contraction below which muscle can`t contract.Any value above this threshold will cause same amount of contraction. Strength of contraction depands upon number of motor units working .

Rigor Mortis- Stiffening of body after death due to depletion of ATP.

Cori Cycle-
Muscle Fatigue-Accumulation of lactic acid at neuromuscular junction causing pain and preventing contraction is called muscle fatigue.

Oxygen Debt- Additional oxygen required to remove all lactic acid formed during excercise is called oxygen debt . Breathing rate therefore remains high for some time after excercise.  

Summation-Many sub-threshold signal when given in a quick manner adds up to cross threshold value.

Difference between Red muscle fibres and white muscle fibres-
Red muscle fibres                      White  muscle fibres 
-Tonic muscle                                                       -Twitch muscle.
-High myoglobin .                                                -Less myoglobin.
-High mitochondria                                               - Less mitochondria
-Aerobic respiration                                             - Anaerobic respiration
-No fatigue                                                           -Fatigue
-Slow and sustained contraction                          - Quick and short duration contraction
-Less ER                                                               - Many ER
e.g. back extensor muscle, flight                          -e.g. eye muscle, flight muscle of crow etc.
      muscle of migratory birds 

Antagonistic muscle:-
 Each part is supplied with a pair of antagonist muscles with opposite action. 

1) Flexor - Bends e.g. Biceps .
    Extensor -extends e.g. Triceps.

2) Abductor - moves arm away from body. e.g. Deltodius.
    Adductor- Moves arm towards body . e.g. Latisimus dorsi.

3) Depressor- Moves jaw below e.g. Depressor mandibuli
     Elevator - Moves jaw up  e.g. Massetor

4)Sphinctor
    Dilator

5) Supinator- Moves palm/sole anterior / up
    Pronator- Moves palm/sole posterior/ down.