ME02 - Muscle Physiology Flashcards
[Skeletal Muscle]
Intrafusal:
Extrafusal:
Gamma/Intrafusal: Muscle Spindle
Alpha/Extrafusal: Muscle Contraction
Types of Extrafusal
Type I: Slow Oxidative (Red)
Type IIb: Fast Glycolytic (White)
Type IIa: Fast Oxidative (Red to Pink)
Complete table
Type I Type IIb Type IIa
Contraction/
ATPase activity
ATP synthesis Rate of fatigue Fiber diameter Activities Location
Complete table
Type I Type IIb Type IIa
Contraction/ Slow Fast Fast/Intermediate
ATPase activity
ATP synthesis Oxidative Glycolytic Oxidative
Rate of fatigue Slow Fast Intermediate
Fiber diameter Small Larger Intermediate
Activities Endurance Quick, Power Uncommon
Posture
Location Soleus, EOMs, abundant SRCA
Antigracity muscles
of back
One SLOW RED OX with a Perfect Posture
Mnemonic yes
Types of Cardiac Muscle Fibers
Atrial Muscle Fibers
Ventricular Muscle Fibers
Conductive Muscle Fibers
Types of Smooth Muscle
Multi-unit Smooth Muscle Unitary Smooth Muscle
Act on their own Act together as one
Controlled by ACh, NE Controlled by hormones, stretch
- Gap Junctions + Gap Junctions
No true AP, Electronic cond. Pacemaker waves, Spike pot.
- Spontaneous contractions Exhibit spontaneous contractions
Ciliary eye muscle, iris Intestines, Bile Ducts, Ureters
piloerector muscle, vas deferens
Fine Motor Control Gross/Movement
Smooth Muscle
Phasic vs Tonic
Phasic Smooth Muscle Tonic Smooth Muscle
Rhythmic, Intermittent Continuously active
Walls of GI, Urogenital Sphincters, Respiratory sm. ms
Component of Skeletal Muscle
Sarcomere»_space; Myofibril»_space; Muscle Fiber»_space; Muscle Fascicle»_space; Skeletal Muscle
Endomysium surrounds _______________
Perimysium surrounds _________________
Epimysium surrounds _________________
Endomysium surrounds Muscle Fiber
Perimysium surrounds Muscle Fascicle
Epimysium surrounds Skeletal Muscle
Plasma membrane that surrounds muscle fiber
Sarcolemma
Invaginations of sarcolemma in close proximity to the terminal cisternae of SR, in 90 degrees
Transverse Tubules
Endoplasmic Reticulum surrounds myofibril
Contains Calcium for muscle contraction
Sarcoplasmic Reticulum
Functional unit of muscle
Between two Z lines
Thick and Thin Filaments
Sarcomere
Thick vs Thin Filaments
THICK Myosin Tail - 2 heavy chains Myosin Head - free ends of heavy chain + light chain Body: Tails bundled together Cross Bridges : Arms and Myosin Heads Hinges : Arm-Body and Arm Head
THIN Actin, Tropomyosin, Troponin Troponin T - attach troponin complex to tropomyosin Troponin I - inhibits actin-myosin Troponin C - calcium binding protein
Muscle Proteins
Titin - scaffolding | Tethers Myosin to Z lines, Binds Z to M lines
Dystrophin - Attach and Stabilize to Plasmalemma, Prevent contraction induced rupture
Actinin and Capz Protein - Binds Actin to Z lines
Desmin - Binds Z lines to plasma membrane
Muscle protein related to Duchenne’s and Dilated Cardiomyopathy
Dystrophin
What happens if Troponin Opens
Muscle contracture happens
Structure
Z line - middle of I band I band A band - everything between I band H band - Thick Filament includes M line M line - Middle line in the Thick Filament
Skeletal Muscle Contraction
Sliding Filament Model
- thin filament slide against thick filament toward center of sarcomere
Z-discs meets the myosin filaments
Steps in Muscle Contraction
Discharge of motor neuron
Release of ACh at MPE
Binding of ACh to Nicotinic ACh receptor
Increased Na and K conductance in MPE
Endplate potential
AP in muscle fibers
Inward spread of depolarization along T tubules
Release of Ca from terminal cisterns of SR
Diffusion to thick and thin filaments
Binding of Ca to troponin C»_space; uncovering myosin binding sites
Formation of cross-linkages between actin and myosnin
Sliding of thin on thick filaments»_space; SHORTENING
Steps in Muscle Relaxation
Ca2+ pumped back into the SR
Release of Ca2+ from troponin
Cessation of interaction between actin and myosin
What is the distance achieved in each cross bridge cycle
10 nanometers