MUSCLE HISTOLOGY

Question 1

Universal property of Muscle tissue

Answer 1

Contractility

Question 2

Types of Myofilaments associated with cell CONTRACTION

Answer 2

1. Thick filaments (Myosin II) 2. Thin filaments (Actin)

Question 3

How many structures make up thick filaments (Myosin II)

Answer 3

1

Question 4

How many structures make up thin filaments (Actin)

Answer 4

F-actin (Polymer formed from G-actin)

G-actin

Question 5

Why are Muscle cells referred to as Muscle Fibres?

Answer 5

Due to their long cylindrical structures

Question 6

Term used to describe Muscle Cell Membrane

Answer 6

Sarcolemma

Question 7

Term used to describe Muscle Cytoplasm

Answer 7

Sarcoplasm

Question 8

Term used to describe Muscle Mitochondria

Answer 8

Sarcosomes

Question 9

Term used to describe Muscle Endoplasmic Reticulum

Answer 9

Sarcoplasmic Reticulum

Question 10

What are the Key features of Skeletal Muscle

Answer 10

Longitudinal

Striations

Multi-nucleated

Nucleus on Peripheral

Question 11

What are the Key features of Cardiac Muscle ?

Answer 11

Intercalated disc (Gap junctions)

Branching Striations

Single nucleus in branches

Question 12

What are the Key features of Smooth Muscle

Answer 12

Spindle shape

Centered Nucleus

No striations

Question 13

Skeletal muscle is invested by a dense collagenous connective tissue known as:

Answer 13

Epimysium (Outermost covering)

Question 14

Each fascicle is surrounded by a looser

connective tissue known as….

Answer 14

Perimysium

Question 15

Each individual muscle fiber within a fascicle is

enveloped by fine reticular fibers known as…

Answer 15

Endomysium

Question 16

In skeletal muscle, each muscle cell, more commonly called a

Answer 16

Muscle fiber which is actually a multinucleated syncytium.

Question 17

Each muscle fiber is formed by the fusion of small, individual muscle cells called…

Answer 17

Myoblasts

Question 18

What are Satellite Cells responsible for ?

Answer 18

The Skeletal muscle’s ability to regenerate (which is limited) in case of any injury

Question 19

The functional unit of the myofibril is the…

Answer 19

Sarcomere

Question 20

The segment of the myofibril between two adjacent Z lines

Answer 20

Sarcomere

Question 21

Arrange the muscle fibre from smallest to largest

Answer 21

1. Myofilament
2. Myofibril
3. Muscle fiber

Question 22

1 Myofibril consists of …

Answer 22

I-MHAS

1. I-Band
2. M line
3. H-zone
4. A-band
5. Sarcomere

Question 23

The term given to the space between two Z lines is known as

Answer 23

Sarcomere

Question 24

Where does Actin filaments attach

Answer 24

Z-line/ Z-disc

Question 25

Where can **only Actin** be found

Answer 25

I-band Z-disk

Question 26

The **overlapping** of myosin filament and actin filament

Answer 26

A-band

Question 27

Where can **only Myosin filaments** be found?

Answer 27

H-zone

Question 28

What happens to **sarcomere** when a **muscle contracts?**

Answer 28

It Shortens

Question 29

When sarcomere shortens during contraction, what else is affected?

Answer 29

**_Z- HI_** Z-line H-zone I-band

Question 30

The **invagination** of the sarcolema (membrane) into the muscle fibre is known as….

Answer 30

Transverse Tubular System-(T-tubule)

Question 31

Where are T tubules located?

Answer 31

Between adjacent terminal cisternae at the **A–I junction**

Question 32

In Skeletal muscle, the complex of T tubule and the two adjacent terminal cisternae is called

Answer 32

A triad

Question 33

What structure encircles the sarcomere and what do they serve as?

Answer 33

Sarcoplasmic Reticulum Serves as a reservoir for Ca2+

Question 34

Are all skeletal muscle fibers the same?

Answer 34

NO

Question 35

There are **three types of skeletal muscle fibers:** they are**…**

Answer 35

* **type I** (slow oxidative), -------------------→SO * **type IIa** (fast oxidative glycolytic),----→FOG * **type IIb** (fast glycolytic) fibers.---------→FG

Question 36

Cardiac Muscle is similar to Skeletal muscle True for False?

Answer 36

True

Question 37

Cardiac Muscle are also known as

Answer 37

Myocytes

Question 38

Key features of Cardiac Muscle

Answer 38

Branched striations Centrally positioned single nucleus Attached to each other by intercalated discs (muscle fiber)

Question 39

Which muscles have the **largest number of mitochondria?**

Answer 39

Cardiac Muscle

Question 40

**Terminal cisternae in Cardiac muscle** are much smaller than in Skeletal muscle. True or False?

Answer 40

True

Question 41

In Cardiac muscle, the complex of T tubule and the terminal cisternae is called

Answer 41

Diads

Question 42

Where are **Diads located?**

Answer 42

At the level of Z-line

Question 43

**Intercalated discs** are specialized **cell-to-cell adhesion junction**. True or False?

Answer 43

True

Question 44

The **cell-to-cell adhesion junctions contain 3 things**.. Name them

Answer 44

**Fascia adherens**(FA) **Maculae adherentes** (desmosomes) (MA) **Gap junctions (GJ)**

Question 45

Which muscle has **no striations**?

Answer 45

**Smoothmuscle**

Question 46

Which muscle has **dense bodies (z line)** attached by **actin and myosin**

Answer 46

Smooth muscle

Question 47

Smooth Muscles are specialized for slow, prolonged contractions. True or False?

Answer 47

True

Question 48

Which muscle is found in hollow organs, such as the stomach, intestine, blood vessels, and bladder.

Answer 48

Smooth Muscles

Question 49

In Smooth muscles, there is no T system. What is the name of the invaginations of the cell membrane called ?

Answer 49

Caveolae

Question 50

List features that **cannot be found in Smooth muscles**

Answer 50

No sarcomeres No myofibrils No striations No T-tubules

Question 51

Which muscles have abundant gap junctions?

Answer 51

Smooth Muscles.

Question 52

A SNAPSHOT OF THE SUMMARY

Answer 52

THE 3 MUSCLES (Know these) Striations T Tubules Gap junctions Regeneration

Question 53

**Socrative** Which of the following is a unique feature of cardiac muscle?

Answer 53

Often Branched

Question 54

**Socrative** Which of the following structure we see the gap junctions, desmosomes, and fascia adherens junctions?

Answer 54

Intercalated discs

Question 55

**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?

Answer 55

Satellite cells

Question 56

**Socrative** Identify the photomicrograph

Answer 56

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.

Question 57

**Socrative** A photomicrograph of skeletal muscle fibers **contain structures called triads**. What do the two lateral components of a triad represent?

Answer 57

Sites for **calcium sequestration and release**

Question 58

**Socrative** The **connective tissue** that forms a sheath around **each muscle fiber is**

Answer 58

Endomysium

Question 59

**Socrative** Multiple peripheral nuclei are seen in which of the following?

Answer 59

Striated Muscle

Question 60

**Socrative** Identify the photomicrograph

Answer 60

Cardiac Muscle