Muscular System Flashcards
Skeletal
Striated, one long continuous fibers and moves out skeleton
Cardiac
Striated, darker lines called intercalated disks and has branches like a tree. Moves your heart
Smooth
Non striated, GI tract, and intestines when you eat. One big tube of smooth muscle moving food.
What is common between skeletal cardiac and smooth?
They move things and they generate heat to contract ATP from the mitochondria
Metabolism
Signalling via Myokines and touching far distant tissues.
Mature myocytes
Helps repair muscle after being torn
Satellite cells
Used for repair
Neurons
Messages from axons to contract
Myocytes
Muscle fibers
Schwann cells
Another type of neuronal cells for support and increase speed of signal
Adipocytes
Fat cells in our muscles provides energy and cushion for protection for muscles to contract.
Fibroblasts
Produce collagen and fiber in connective tissues
Immune cells
Everywhere in the body, smooth muscle cells, vascularization from blood oxygen nutrition where blood vessel have smooth muscle layers
Endothelial cells
Deeps layer is the epithelial. Forms a single cell layer that lines all blood vessels and regulates exchanges between the bloodstream and surrounding tissues
Blood cells and hematopoietic stem cells
Are just pre blood cells and blood cells within that
Fascicles
A bundle of structures such as nerve or muscles fibers covered by the perimysium
Perimysium
The sheath of connective tissue surrounding bundles of muscle fibers to form the fascicles
Endomysium layer
Surrounds the muscles fibers with a delicate layer. Provides nutrition and capillaries
Epimysium
Connective tissue that Surrounds the entire muscle
Sarcolemma
The fine transparent tubular sheath which envelops the fibers of skeletal muscles
Sarcomeres
The smallest contractile unit of the skeletal striated muscle made from the myofibril of actin(thin) and myosin(thick). Also separated by zig zag lines. Two zlines is 1 sarcomere
Fascia
Dense connective tissue layer around the muscles
What is the order?
Epimysium->perimysium->fascicles->endomysium->myofibers-> myofibrils-> actin and myosin for contraction
What is type 1 muscle fiber type?
Slow twitch: thinner and relies on oxidative metabolism energy system. Darker in color because hemoglobin has more iron in it and this carries more red blood cells. Has more mitochondria than type 2 since it builds off stability and lasting longer so needs more ATP.
What is type x muscle fiber?
Crossover between 1 and 2: fast oxidative glycolytic
What is type 2b muscle fiber?
Stronger and faster and EXPLOSIVE ENERGY. but gets more fatigued and lacks stability. It is lighter in color with less blood supply. Glycolytic energy system
All of none principle
Motor neuron innervates those fibers, all contract/or none will contract within a motor unit.
Pattern of motor unit recruitment
Recruit small or big, type 1 or type 2. There is a pattern
What happens in muscle contraction?
- Motor neuron stimulates skeletal muscle cell.
- Calcium is released from the sarcoplasmic reticulum
- Cross-Bridge cycling/contraction
Shortened version of muscle contraction
-depolarization and calcium ion release
-actin and myosin cross-bridge formation
-sliding mechanism of actin and myosin filaments
-sarcomere shortening (muscle contraction)
7 steps of MC
- Action potential generated which stimulates muscle
- Ca2+ released
- Ca2+ binds to troponin, shifts actin and exposes binding sites
- Myosin cross bridges attach and detach, pulling actin filaments toward center (requires ATP)
- Muscle contracts
- Ca2+ removed, shifts actin filaments to original position, blocking binding sites
- Muscle contraction stops
Concentric
Velocity >0. Uses a lot more ATP like going up the stairs
Isometric contraction
Velocity =0.
Eccentric
Velocity<0 lengthens and no force produced
T-tubules
Small tubules which run transversely through a striated muscle fiber and which electrical impulses are transmitted from the sarcoplasm to the fibers interior
Summary of skeletal muscle contractions
- Calcium is released from the sarcoplasmic reticulum close to the t-tubules.
- Ca2+ binds for troponin
-> troponin moves tropomyosin off myosin binding site of actin - Myosin head, ADP+P bounds and binds to actin
- P and ADP falls off from power strokes
- ATP head binding site revealed.
- Myosin ATPase (enzyme) hydrolyzes ATP into ADP+P-> myosin head re-cocked and ready for TAKE OFF