Chapter 10 - muscle tissue Flashcards
muscular abilities (4)
excitable- respond to a stimulus
contractable - shorten in length
extensible - extend or stretch
elastic - return to original shape
5 main functions of muscular tissue
- create motion by working with nerves, bones, and joints
- maintain posture
- sphincters - keep substances in one place
- peristatic contractions - move substances through tubes by waves of contractions
- generate heat - thermogenesis (shivering = involuntary muscle contraction)
skeletal muscle
function, appearance, control
location - skeleton
function - movement, posture, health generation
appearance - started, multi-nucleated, parallel fibres
control - voluntary
components of a skeletal muscle
-CT covering muscle units
-Under fascia is the epimysium (surrounds muscles)
Perimysium - fascicles
Endomysium - fibers
components of a skeletal muscle fiber
- Fiber - a muscle cell
- Sarcolemma - PM of muscle cell
- T-tubules - continuation of sarcolemma
- Sarcoplasmic Reticulum - creates mesh-like structure that ends in the terminal cisternae.
- Terminal Cisternae holds calcium
- Sarcoplasm - cytoplasm for muscle cells
what are muscle fibres built from? name and describe these 3 components.
- contractile proteins
- made up of actin and myosin
- generate muscle contraction - Regulatory proteins
- troponin and tropomyosin
- switch the calcium process on and off - structural proteins
- connectin and dystrophin
- link MF to PM of sarcolemma
- keep thick and thin filaments together
name and describe the 2 contractile proteins
- thin filaments - made of the protein actin
2. thick filaments – made of the protein myosin
How do regulatory proteins work?
Ca2+ binds to troponin which changes the shape of the troponin-tropomyosin complex and uncovers the myosin binding sites on actin
what is the sliding-filament mechanism?
thick and thin filaments slide past one another during muscle contraction
explain the process of the sliding0filament mechanism.
- Contraction is initiated when Ca2+ is released into the sarcoplasm
- Calcium binds to Troponin, moves Tropomyosin off the myosin binding sites
- Thick and thin can now “slide on one another
- Sarcomere is shortened
what produces tension in a muscle?
sarcomere shortening produces tension
Explain Excitation - Contraction coupling
- EC coupling involves putting it all together
- Thought process in the brain
- Action Potential (nerve signal) arrives at the neuro-muscular junction
- regeneration of action potential alone the sarcolemma
- Release of calcium from sarcoplasmic reticulum
- Sliding of thick on thin filaments
- Generate muscle tension = work
what occurs at the neuromuscular junction
- activation of motor neuron -acetylcholine (Ach) is released
- Ach broken down by acetylcholinesterase
- Breakdown and diffusion of Ach out of synaptic cleft
- motor endplate has many ligand-gated sodium channels
* CHECK*
sources of muscular energy and duration of produced contraction.
- stored ATP - 3 secs
2. energy from stored creatine phosphate (easily available) - 12 seconds
describe aerobic ATP production
- oxidative
- cellular respiration in mitochondria (1 glucose = 36 ATP)
- requires oxygen
- slow
Using anaerobic glucose for energy
- glycolosis
- glucose + 2 pyruvate = 2 atp
- no o2, faster, 30-40 seconds
characteristics of red muscle fibers
- numerous mitochondiras
- lots of myoglobin (protein that binds 02)
- lots of energy stores
- lots of blood supply
characteristics of white muscle fibers
- less myoglobin and mitochondria
- les blood supply
characteristics of slow oxidative muscle fibres.
- small
- dark red
- least powerful
- fatigue resistance
characteristics of oxidative-glycolytic fibres (FOG)
- Intermediate in size
- appear pink
- moderately resistant to fatigue
characteristics of fast glycolytic fibres (FG)
-Large
-white
-powerful
-Fatigue quickly
(many of these present in body builders)
Cardiac Muscle
location, function, appearance, control
location - heart
function - continuously pump blood
appearance - striated, one central nucleus
control - involuntary
true or false:
In response to a single AP, cardiac muscle contracts 10-15 times longer than skeletal muscle due to prolonged delivery of Ca2+
true
Visceral (smooth) muscle
location, function, appearance, control
location - GI Tract, uterus, eye, blood vessels
function - peristalsis, BP, pupil size, erects hair
appearance - no striations, one central nucleus
control - involuntary
