Chapter 11 - Muscular System Flashcards
What connective tissue wraps each muscle fiber?
Endomysium
What connective tissue wraps fascicles?
Perimysium
What are the three types of muscles?
- Skeletal
- Cardiac
3 Smooth
What are the functions of muscle? (There are 6)
- Motion
- Posture
- Produce heat
- Joint stability
- Guard entrances and exits
- “Communicate”
What connective tissue covers skeletal muscle?
Epimysium
What covers each skeletal muscle and it’s epimysium connective tissue?
Deep fascia
What is a tendon?
Fibrous tissue, connects muscle to bone
What is an aponeurosis?
Pearly white fibrous tissue, like a tendon, but over sheetlike muscles
Ex: Head, rectus abdominis
Muscles contained within a particular region are called…
Intrinsic muscles
Muscles that act upon a designated region, but have an origin elsewhere are called…
Extrinsic muscles
What is the cytoplasm of a muscle cell?
Sarcoplasm
What is the endoplasmic reticulum of a muscle cell?
Sarcoplasmic reticulum
What controls calcium ion concentration?
Sarcoplasmic reticulum
What is the cell membrane of a muscle cell?
Sarcolemma
What surface do nerve impulses travel over?
Hint: It separates intracellular and extracellular spaces
Sarcolemma
The sarcoplasm contains large amounts of…
Glycogen and Myoglobin
What is Myoglobin? What does it do in muscles?
An oxygen-binding protein; temporarily stores oxygen in muscle tissue
What does Glycogen do in muscle contraction?
Glycogen makes glucose (the fuel source!)
What part of the muscle is the ‘“contractile unit”?
Sarcomere
What are the six proteins found in a sarcomere?
- Actin - thin filaments
- Myosin - thick filaments
- Tropomyosin
- Troponin
- Titin - elastic filament
- Nebulin
What are Cisternae?
Sac - like storage chambers Positioned over Z-Lines Has high concentration of Ca++ Releases Ca++ during contraction Reabsorbs Ca++ during relaxation
What are Transverse Tubules?
In between Cisternae
Carry nerve impulses to Cisternae
Tell Cisternae to release Ca++ to contract muscles
Lumen of T-Tubule is continuous with extracellular space
What is a triad made of?
2 Cisternae and a T-Tubule
What are two Cisternae and a T-tubule called?
Triad
What is the end of a nerve cell?
Synaptic knob
What is the small space between neuron and muscle?
Synaptic cleft
What part of the nerve cell stores neurotransmitters?
Synaptic vesicles
What is the motor end plate?
The part directly underneath the neuromuscular junction
What is a Synaptic knob?
The end of a nerve cell
What is a Synaptic cleft?
The small space between neuron (nerve cell) and muscle
What is a Synaptic vesicle?
The part of the nerve cell that stores neurotransmitters
What neurotransmitter is released in muscle contraction?
Acetylcholine (ACh)
What is a motor unit?
A motor neuron + all the muscle fibers it supplies
Where would you find small motor units?
Eye or finger muscles
Places of fine muscle control
Where would you find large motor units?
Leg muscles (gastrocnemius in calf)
What theory explains muscle contraction?
SLIDING FILAMENT THEORY
What is the Power Stroke?
When myosin heads swivel towards the center of a sarcomere
What does Ca++ do in muscle contraction?
It binds to Troponin and moves Tropomyosin, exposing myosin binding sites on actin
What does ATP do in muscle contraction?
“Cock” myosin heads
Release + attach myosin from myosin binding sites of actin
What principle says that individual muscle fibers will contract to their fullest or not at all?
All-or-nothing principle
What is the all-or-nothing principle?
Principle that individual muscle fibers will contract to their fullest or not at all.
What breaks down Acetylcholine (ACh)?
Acetylcholinesterase (AChE)
What happens to Ca++ during muscle relaxation?
Transported from sarcoplasm into sarcoplasmic reticulum
What gathers Ca++ back into Cisternae (in Sarcoplasmic Reticulum)?
Calsequestrin
What happens during Rigor Mortis?
Ca++ leaks out of sarcoplasmic reticulum after death
No ATP to break myosin heads away from myosin binding sites on actin
Like a permanent Charlie Horse
What are the three sources of energy in muscle contraction?
- ADP and Creatine Phosphate
- Aerobic respiration
- Anaerobic respiration
What makes energy with oxygen?
Aerobic respiration
What makes energy WITHOUT oxygen? What does it use instead?
Anaerobic respiration
Uses Lactic Acid (turned to glucose in liver) instead
What creates sore muscles?
Lactic Acid
What can happen when Lactic acid creates a low pH in muscles cells?
Low pH can denature proteins
How is Lactic acid removed?
It is taken to the liver and turned into glucose
What is a contracture?
A state of continuous contractions
What is a state of continuous contractions?
A contracture
What is “Multiple Unit Summation”?
The process of increasing the number of active motor units to increase the degree of contraction.
What are the four periods of a muscle “twitch”?
- Latent period
- Contraction period
- Relaxation period
- Refractory period
What is a Myogram? What is another name for it?
A single muscle contraction; “twitch”
What are the two types of smooth muscle?
Multiunit Smooth Muscle and Single Unit (Visceral) Smooth Muscle
What is an example of a Multiunit Smooth Muscle?
Irises of Eyes
What is an example of a Single Unit (Visceral) Smooth Muscle?
Hollow Organs
What is peristalsis?
Smooth muscle contraction moves food through digestive system
What are intercalated discs?
Discs that bind cardiac muscle cells together
What are gap junctions?
Small gaps between muscle cells
Allow muscles to “communicate” (electrical impulses and molecules to pass between them)
Homeostatic imbalances are anything that blocks these two neurotransmitters:
Acetylcholine (ACh) and Acetylcholinesterase (AChE)
_____ blocks nerve transmissions in muscle cells
Hint: Used in poison darts!
Curare; Tubocurarine
These two chemicals block AChE:
Clostridium tetani (Tetnus) and Clostridium botulinum (Botulism)
What is the most abundant muscular protein?
Myosin
