6.9 Muscles - The Structure and Function of Muscle Tissue Flashcards
What are the functions of muscle?
- Motion
- Stability
- Organ volume regulation
- Soft tissue support
- Temperature maintenance
- Nutrient Storage
(MSNOTS)
What is the name given to the type of control that enables the heart to contract as one coordinated unit?
Autorhythmic
Does the heart need nervous innervation to function?
No; the sinoatrial node acts as the pacemaker, generating action potentials
Which type of muscle is striated/not striated?
Striated: Cardiac, skeletal
Non-Striated: Smooth
Describe the arrangement of smooth muscle nuclei
Single, centralised
What are the two kinds of smooth muscle?
- Visceral (single-unit)
- Multi-unit
Describe the defining characteristics of visceral smooth muscle
- Multiple muscle cells form one unit
- Gap junctions allow unison contraction
Where can visceral smooth muscle be found?
Blood vessels, hollow organs
Describe the defining characteristics of multiunit smooth muscle
- Each muscle has own nerve ending
- Contract independently
Where can multiunit smooth muscle be found?
- Airways
- Arrector pili
Can cardiomyocytes regenerate if injured (e.g. ischaemia)?
No. They heal via fibrosis (scarring; loss of function)
Can smooth muscle cells regenerate? Can they grow in size and number?
Yes and yes (e.g. uterus thickening)
What is the name of the junction between a bone and a skeletal muscle?
Tendinous-periosteal junction
What are the types of fibres that give skeletal muscle its striated appearance?
Actin and myosin
Are skeletal muscle cells uninucleated or multinucleated
Multinucleated
Which type of nervous system innervates skeletal muscles?
Somatic; conscious control
Describe the formation of skeletal muscle cells
Formed from 100s of embyronic myoblasts (stem cells) fusing to form one cell
What are unfused myoblasts known as?
Satellite cells
Can skeletal muscle cells divide/be replaced?
Divide: No
Replaced: Yes, by satellite cells (stem cells)
What is a muscle cell membrane called?
Sarcolemma
What is muscle cell cytoplasm called?
Sarcoplasm
What are five things that are located in sarcoplasm?
- Mitochondria
- Glycogen
- Myoglobin
- Transverse (T) Tubules
- Sacroplasmic Reticulum
List, from inside to outside, layers and connective tissue of muscle. Then draw a diagram
- Endomysium
- Fascicle
- Perimuysium
- Muscle
- Epimysium
- Tendons
How many motor neurons innervate a single muscle fibre?
1
Which of actin and myosin filaments are thick and thin?
Thick: Myosin
Thin: Actin
How do myofibrils fit into the order of muscle organisation?
There are hundreds of myofibrils in the sarcoplasm of a single muscle cell
What is the name of contractile units of muscle?
Sarcomeres
