Wk 3: Muscle Tissue Flashcards
Does striated muscle or non striated (smooth) muscle contain sarcomeres
Striated muscle contains sarcomeres
Morphological & Functional classification of skeletal muscle
Striated & voluntary
Morphological & Functional classification of cardiac muscle
Striated & involuntary
Morphological & Functional classification of smooth muscle
Non striated & involuntary
6 functions of skeletal muscle
- Produces movement
- Maintain posture
- Support viscera (soft internal organs of body)
- Guards entrances & exits
- Maintains body temp
- Stores nutrients
Skeletal muscle is composed of what specialised cells & what is their purpose
- Muscle fibres
- Their function is contractability
What are the 3 layers of CT surrounding the skeletal muscles
- Epimysium
- Perimysium
- Endomysium
What type of CT is the epimysium
Dense irregular CT
Function of epimysium (2)
- Maintains structural integrity
- Projects inwards & divides muscle into compartments of muscle fibre bundles (fasciculi)
Function of the perimysium (1)
Surrounds each fasciculus
What is the endomysium composed of
CT layer of collagen & reticular fibres
Function of endomysium
Encases each muscle fibre within a fascicle
What is a myocyte (muscle fibre)
A muscle cell
What is the sarcolemma
The plasma membrane
What is the sarcoplasm
The cytoplasm
What is the sarcoplasmic reticulum
Smooth ER
What is the sarcosome
The mitochondria
What is the sarcomere
FUnctional unit of muscle
What does the sarcomere contain
- COntractile myofilaments
- Thin filament = actin
- Thick filament = myosin
Myofilaments + _______ = sarcomere
Regulatory proteins - troponin & tropomyosin
Where does actin project from & to
Actin & troponin-tropomyosin complex projects from Z discs towards centre of sarcomere
Where does myosin project from & to
Myosin strands project from centre of sarcomere towards Z-discs (thick filaments)
What happens to the filaments when the muscle is relaxed
- Thick filaments don’t extend entire length of sarcomere
- Thin filaments don’t meet in the middle
What is the I band of the sarcomere
Adjacent portion of 2 sucessive sarcomeres
What is the A band of the sarcomere
Encompasses entire length of thick filaments (myosin)
What is the H band of the sarcomere & what is it bisected by
- The H band is the zone in the middle of the A band, devoid of thin filaments
- H band is bisected by M line
What happens to the 2 filaments during muscle contraction
- Thick & thin filaments do not shorten
- Z discs are brought closer together as thin filaments slide past thick filaments
Where is smooth muscle found
Found in walls of hollow organs:
* Urinary bladder
* Uterus
* Stomach
* Intestines
And in walls of passageways
* Arteries & veins
* Tracts of resp, urinary, reproductive systems
How does smooth muscle contract
- Calcium calmodulin complex activates myosin kinase which activates the myosin heads via phosphorylation
- Heads attach to actin binding sites & pull on thin filaments
- Thin filaments are anchored to dense bodies
- The thin filaments pull on dense bodies
Function of cardiac muscle (myocardium)
pump blood in circulatory system
What cells coordinate the contraction of myocarium tissue
Pacemaker cells
