MUSCLE HISTOLOGY Flashcards
Universal property of Muscle tissue
Contractility
Types of Myofilaments associated with cell CONTRACTION
- Thick filaments (Myosin II) 2. Thin filaments (Actin)
How many structures make up thick filaments (Myosin II)
1
How many structures make up thin filaments (Actin)
F-actin (Polymer formed from G-actin)
G-actin
Why are Muscle cells referred to as Muscle Fibres?
Due to their long cylindrical structures
Term used to describe Muscle Cell Membrane
Sarcolemma
Term used to describe Muscle Cytoplasm
Sarcoplasm
Term used to describe Muscle Mitochondria
Sarcosomes
Term used to describe Muscle Endoplasmic Reticulum
Sarcoplasmic Reticulum
What are the Key features of Skeletal Muscle
Longitudinal
Striations
Multi-nucleated
Nucleus on Peripheral
What are the Key features of Cardiac Muscle ?
Intercalated disc (Gap junctions)
Branching Striations
Single nucleus in branches
What are the Key features of Smooth Muscle
Spindle shape
Centered Nucleus
No striations
Skeletal muscle is invested by a dense collagenous connective tissue known as:
Epimysium (Outermost covering)
Each fascicle is surrounded by a looser
connective tissue known as….
Perimysium
Each individual muscle fiber within a fascicle is
enveloped by fine reticular fibers known as…
Endomysium
In skeletal muscle, each muscle cell, more commonly called a
Muscle fiber which is actually a multinucleated syncytium.
Each muscle fiber is formed by the fusion of small, individual muscle cells called…
Myoblasts
What are Satellite Cells responsible for ?
The Skeletal muscle’s ability to regenerate (which is limited) in case of any injury
The functional unit of the myofibril is the…
Sarcomere
The segment of the myofibril between two adjacent Z lines
Sarcomere
Arrange the muscle fibre from smallest to largest
- Myofilament
- Myofibril
- Muscle fiber
1 Myofibril consists of …
I-MHAS
- I-Band
- M line
- H-zone
- A-band
- Sarcomere
The term given to the space between two Z lines is known as
Sarcomere
Where does Actin filaments attach
Z-line/ Z-disc
Where can only Actin be found
I-band
Z-disk
The overlapping of myosin filament and actin filament
A-band
Where can only Myosin filaments be found?
H-zone
What happens to sarcomere when a muscle contracts?
It Shortens
When sarcomere shortens during contraction, what else is affected?
Z- HI
Z-line
H-zone
I-band
The invagination of the sarcolema (membrane) into the muscle fibre is known as….
Transverse Tubular System-(T-tubule)
Where are T tubules located?
Between adjacent terminal cisternae at the A–I junction
In Skeletal muscle, the complex of T tubule and the two adjacent terminal cisternae is called
A triad
What structure encircles the sarcomere and what do they serve as?
Sarcoplasmic Reticulum
Serves as a reservoir for Ca2+
Are all skeletal muscle fibers the same?
NO
There are three types of skeletal muscle fibers: they are…
- type I (slow oxidative), ——————-→SO
- type IIa (fast oxidative glycolytic),—-→FOG
- type IIb (fast glycolytic) fibers.———→FG
Cardiac Muscle is similar to Skeletal muscle
True for False?
True
Cardiac Muscle are also known as
Myocytes
Key features of Cardiac Muscle
Branched striations
Centrally positioned single nucleus
Attached to each other by intercalated discs (muscle fiber)
Which muscles have the largest number of mitochondria?
Cardiac Muscle
Terminal cisternae in Cardiac muscle are much smaller than in
Skeletal muscle.
True or False?
True
In Cardiac muscle, the complex of T tubule and the terminal cisternae is called
Diads
Where are Diads located?
At the level of Z-line
Intercalated discs are specialized cell-to-cell adhesion junction.
True or False?
True
The cell-to-cell adhesion junctions contain 3 things.. Name them
Fascia adherens(FA)
Maculae adherentes (desmosomes) (MA)
Gap junctions (GJ)
Which muscle has no striations?
Smoothmuscle
Which muscle has dense bodies (z line) attached by actin and myosin
Smooth muscle
Smooth Muscles are specialized for slow, prolonged contractions.
True or False?
True
Which muscle is found in hollow organs, such as the stomach, intestine, blood vessels, and bladder.
Smooth Muscles
In Smooth muscles, there is no T system. What is the name of the invaginations of the cell membrane called ?
Caveolae
List features that cannot be found in Smooth muscles
No sarcomeres
No myofibrils
No striations
No T-tubules
Which muscles have abundant gap junctions?
Smooth Muscles.
A SNAPSHOT OF THE SUMMARY
THE 3 MUSCLES (Know these)
Striations
T Tubules
Gap junctions
Regeneration
Socrative
Which of the following is a unique feature of cardiac muscle?
Often Branched
Socrative
Which of the following structure we see the gap junctions, desmosomes, and fascia adherens junctions?
Intercalated discs
Socrative
A 7-year-old girl sustains a small tear in her deltoid muscle when she is involved in a bicycle accident. Regeneration of the muscle will occur due to which of the following cells?
Satellite cells
Socrative
Identify the photomicrograph
Skeletal Muscle
Explanation:
The attached micrograph shows the transverse section of skeletal muscle. The nucleus (dark points)along with cell organelles are present at the periphery due to the predominant arrangement of myofibrils in each muscle fiber.
Socrative
A photomicrograph of skeletal muscle fibers contain structures called triads. What do the two lateral components of a triad represent?
Sites for calcium sequestration and release
Socrative
The connective tissue that forms a sheath around each muscle fiber is
Endomysium
Socrative
Multiple peripheral nuclei are seen in which of the following?
Striated Muscle
Socrative
Identify the photomicrograph
Cardiac Muscle
