Muscle Tissue 🏋️‍♀️

Question 1

Muscle Tissue

Answer 1

Consists of contractile cells and responsible for movement. Derived from the mesoderm.

Question 2

Myofibrils

Answer 2

Bundles of myofilaments and the structural and functional subunit of the muscle cell.

Question 3

Actin/thin filaments

Answer 3

Composed mainly of F-actin, with associated proteins like tropomyosin, troponin complex, and nebulin for regulation and stabilization.

Question 4

I-band

Answer 4

Region of the sarcomere where only thin (F-actin) filaments are present.

Question 5

Sliding Filament Hypothesis of Huxley

Answer 5

Theory explaining muscle contraction where myofilaments slide past each other without changing length.

Question 6

Sarcoplasmic reticulum

Answer 6

Membranous network around myofibrils that stores calcium ions and communicates with T-tubules in muscle cells.

Question 7

Muscle Spindle

Answer 7

Encapsulated sensory receptor in muscle belly that senses changes in muscle length or stretch, containing modified muscle fibers.

Question 8

Smooth Muscle Cells

Answer 8

Cells that secrete connective tissue matrix, synthesize various types of collagens and elastin, and possess well-developed rER and golgi.

Question 9

Sarcomere

Answer 9

The specific organization of contractile proteins of the myofibril observed in all striated muscle types.

Question 10

Sarcomere

Answer 10

Basic contractile unit of striated muscles containing thick (myosin II) and thin (F-actin) filaments.

Question 11

H-band

Answer 11

Central region of the sarcomere made up of thick filaments (myosin II) only.

Question 12

Golgi Tendon Organ

Answer 12

Encapsulated proprioceptor located at myotendinous junction that senses tension in muscles and is part of the Golgi tendon reflex.

Question 13

Peripheral protein

Answer 13

Proteins found on the periphery of membranes or structures, serving various functions such as structural support or cell signaling.

Question 14

T tubules

Answer 14

Extensions of the cell membrane that help transmit action potentials deep into muscle fibers, facilitating muscle contraction.

Question 15

Gap junctions

Answer 15

Specialized protein channels that allow direct communication and passage of ions and small molecules between adjacent cells.

Question 16

Contractile cells

Answer 16

Cells responsible for muscle movement, such as myofibers. Derived from the mesoderm.

Question 17

Myosin II/thick filament

Answer 17

Motor protein binding to actin subunits in striated muscles for movement, consisting of head and tail regions connected by a lever arm in the S2 region.

Question 18

A-band

Answer 18

Region of the sarcomere where thick filaments (myosin II) are predominantly located.

Question 19

Myofilaments

Answer 19

Contractile proteins (F-actin, myosin II) responsible for muscle contraction.

Question 20

Intercalated Discs

Answer 20

Attachment sites between adjacent cardiac myocytes, containing macula adherens and fascia adherens for structural integrity.

Question 21

Juxtanuclear region

Answer 21

The area near the nucleus of a cell, often involved in functions related to transport, signaling, or organelle positioning.

Question 22

Myofilaments

Answer 22

Contractile proteins/elements occupying the bulk of the sarcoplasm, classified into thin filaments mainly composed of F-actin and thick filaments mainly composed of myosin II.

Question 23

Actomyosin Cross-Bridge Cycle

Answer 23

Series of stages in muscle contraction involving attachment, release, bending, force generation, and reattachment.

Question 24

Duchenne Muscular Dystrophy

Answer 24

Genetic disorder characterized by progressive muscle weakness, typically fatal in early adulthood due to breakdown of muscle fibers.

Question 25

Purkinje Fibers

Answer 25

Modified cardiac muscle cells specialized for conducting impulses of the A-V bundle and synchronizing ventricular contraction.

Question 26

Myosin light chain kinase

Answer 26

Enzyme responsible for phosphorylating myosin, leading to muscle contraction by interacting with actin filaments.

Question 27

Hypertrophy and hyperplasia response

Answer 27

Cellular growth due to increased demand or stimulation, involving either enlargement of existing cells (hypertrophy) or increase in cell number (hyperplasia).