L6 - Connective Tissue

Question 1

1. Which of the following is NOT a component of connective tissue?
   A) Cells
   B) Extracellular matrix
   C) Fibers
   D) Neurons

Answer 1

1. D) Neurons
   o Rationale: Connective tissue is composed of cells, extracellular matrix, and fibers, not neurons.

Question 2

2. What is the primary function of fibroblasts in connective tissue?
   A) Storing fat
   B) Phagocytosis
   C) Production and maintenance of fibers and ground substance
   D) Antibody production

Answer 2

2. C) Production and maintenance of fibers and ground substance
   o Rationale: Fibroblasts are the most common connective tissue cells and are responsible for producing the extracellular matrix.

Question 3

3. Type I collagen fibers are primarily found in:
   A) Cartilage
   B) Bones, tendons, and the dermis of the skin
   C) Lymph nodes and bone marrow
   D) The basement membrane

Answer 3

3. B) Bones, tendons, and the dermis of the skin
   o Rationale: Type I collagen fibers are thickest and provide tensile strength to tissues like bones and tendons

Question 4

4. Which type of connective tissue is primarily involved in providing elasticity to structures like the aorta?
   A) Dense irregular connective tissue
   B) Elastic connective tissue
   C) Hyaline cartilage
   D) Fibrocartilage

Answer 4

4. B) Elastic connective tissue
   o Rationale: Elastic fibers allow structures like the aorta to stretch and return to their original shape.

Question 5

5. Which of the following is true about adipose cells (adipocytes)?
   A) They have a centrally located nucleus
   B) They are responsible for producing antibodies
   C) They store large lipid droplets and have a peripherally placed nucleus
   D) They synthesize collagen fibers

Answer 5

5. C) They store large lipid droplets and have a peripherally placed nucleus
   o Rationale: Adipocytes are specialized for fat storage and have a nucleus pushed to the cell’s periphery.

Question 6

6. Fibroblasts are known as fibrocytes in their active state.
   True / False

Answer 6

6. False
   o Rationale: Fibroblasts are active, and they become fibrocytes in their resting stage.

Question 7

7. Reticular fibers are made of type III collagen fibers and can be stained with hematoxylin and eosin stain.
   True / False

Answer 7

7. False
   o Rationale: Reticular fibers are stained using silver staining methods, not hematoxylin and eosin.

Question 8

8. Hyaline cartilage has a perichondrium and contains collagen fibers.
   True / False

Answer 8

8. True
   o Rationale: Hyaline cartilage is covered by perichondrium and contains collagen fibers in its matrix.

Question 9

9. _____ is the type of connective tissue responsible for forming the skeletal basis of the ear and epiglottis.

Answer 9

9. Elastic cartilage
   o Rationale: Elastic cartilage provides the flexibility needed in structures like the ear and epiglottis.

Question 10

11. The protein found in elastic fibers that allows them to stretch is called _____.

Answer 10

11. Elastin
    * Rationale: Elastin is the protein responsible for the elasticity of elastic fibers.

Question 11

10. The spaces within bone where osteocytes are located are called _____.

Answer 11

10. Lacunae
    * Rationale: Lacunae are small spaces that house osteocytes in bone.

Question 12

12. Which of the following are types of dense connective tissue? (Select all that apply)
    A) Areolar tissue
    B) Regular dense connective tissue
    C) Reticular tissue
    D) Irregular dense connective tissue
    E) Elastic connective tissue

Answer 12

12. B, D, E
    * Rationale: Regular dense connective tissue, irregular dense connective tissue, and elastic connective tissue are all types of dense connective tissue.

Question 13

13. Explain the role of mast cells in connective tissue.

Answer 13

13. Mast cells are involved in immune responses and are found in connective tissues. They contain granules rich in histamine and heparin, which play a role in allergic reactions and inflammation.

Question 14

14. What is the primary difference between compact bone and spongy bone?

Answer 14

14. Compact bone has a dense structure with organized lamellae and osteons, while spongy bone consists of trabeculae with spaces filled by bone marrow.

Question 15

15. A 65-year-old patient presents with joint pain and difficulty walking. Imaging reveals degeneration of the cartilage in his knee joint. Based on this information, what type of connective tissue is most likely affected, and what are its key characteristics?

Answer 15

15. The affected tissue is hyaline cartilage, which provides support with flexibility and resists compressive forces. It is found in joints, trachea, and the nose, and is essential for smooth joint movements.

Question 16

16. A newborn is diagnosed with a genetic disorder that affects collagen synthesis. Which connective tissue structures would be primarily impacted, and how might this present clinically?

Answer 16

16. Collagen synthesis defects would primarily affect tissues with high collagen content such as skin, bones, tendons, and ligaments. Clinically, this may present as joint instability, skin fragility, and delayed wound healing.

Question 17

17. Which of the following cartilage types lacks a perichondrium?
    A) Hyaline cartilage
    B) Elastic cartilage
    C) Fibrocartilage
    D) Both A and C

Answer 17

17. C) Fibrocartilage
    * Rationale: Fibrocartilage does not have a perichondrium and is found in intervertebral discs and the pubic symphysis.

Question 18

18. What type of connective tissue provides the primary structural framework for organs like the spleen and lymph nodes?
    A) Dense regular connective tissue
    B) Reticular connective tissue
    C) Hyaline cartilage
    D) Elastic connective tissue

Answer 18

18. B) Reticular connective tissue
    * Rationale: Reticular connective tissue provides the supportive framework for lymphoid organs like the spleen and lymph nodes.

Question 19

19. Which type of ossification involves the direct transformation of mesenchyme into bone?
    A) Cartilaginous ossification
    B) Membranous ossification
    C) Endochondral ossification
    D) Secondary ossification

Answer 19

19. B) Membranous ossification
    * Rationale: In membranous ossification, bones develop directly from mesenchyme without a cartilage precursor.

Question 20

20. Which of the following cells are responsible for bone resorption (breakdown of bone tissue)?
    A) Osteoblasts
    B) Osteocytes
    C) Osteoclasts
    D) Chondrocytes

Answer 20

20. C) Osteoclasts
    * Rationale: Osteoclasts are responsible for breaking down bone tissue during bone remodeling and resorption.

Question 21

21. Bone marrow is responsible for producing blood cells and is involved in erythropoiesis.
    True / False

Answer 21

21. True
    * Rationale: Red bone marrow is responsible for erythropoiesis, the production of red blood cells.

Question 22

22. Chondroblasts are mature cartilage cells located in the lacunae, while chondrocytes are young cartilage cells found in the perichondrium.
    True / False

Answer 22

22. False
    * Rationale: Chondroblasts are young cartilage cells in the perichondrium, while chondrocytes are mature cells located in lacunae.

Question 23

23. The process by which bones develop from cartilage models is called _____.

Answer 23

23. Endochondral ossification
    * Rationale: Endochondral ossification is the process by which cartilage is replaced by bone during development.

Question 24

24. In compact bone, the concentric plates of bony tissue surrounding the Haversian canal are called _____.

Answer 24

24. Concentric lamellae
    Rationale: Concentric lamellae are the layers of bone tissue arranged around the Haversian canal in compact bone.

Question 25

25. Which of the following are functions of bone tissue? (Select all that apply)
    A) Protecting vital organs
    B) Providing structural support to the body
    C) Regulating blood calcium levels
    D) Manufacturing antibodies
    E) Assisting in locomotion and movement

Answer 25

25. A, B, C, E
    * Rationale: Bones provide support, protect vital organs, regulate calcium levels, and assist in movement.

Question 26

26. Describe the structure and function of the periosteum in bone tissue.

Answer 26

26. The periosteum is a double-layered membrane covering the external surface of bones. The outer fibrous layer contains dense irregular connective tissue, while the inner cellular layer contains osteoprogenitor cells and osteoblasts. It plays a role in bone growth, repair, and nourishment.

Question 27

27. Compare and contrast hyaline cartilage and fibrocartilage in terms of structure, function, and location in the body.

Answer 27

27. Hyaline cartilage has a homogeneous matrix and provides support and flexibility. It is found in the ribs, trachea, and nose. Fibrocartilage, on the other hand, contains dense bundles of collagen fibers and is found in structures requiring tensile strength, like intervertebral discs. Unlike hyaline cartilage, fibrocartilage lacks a perichondrium.

Question 28

28. A 30-year-old female is experiencing frequent fractures despite minimal trauma. Her lab results show an abnormally low bone density. Explain what connective tissue might be involved and the potential cellular mechanisms contributing to her condition.

Answer 28

28. The connective tissue involved is bone, specifically due to issues with osteoblast activity and osteoclast overactivity, leading to decreased bone density (osteoporosis). Reduced osteoblast function and increased bone resorption by osteoclasts could contribute to her frequent fractures.

Question 29

29. An elderly patient has been diagnosed with atherosclerosis, a condition in which arteries become stiff due to the buildup of fatty deposits. Which type of connective tissue is primarily involved in this condition, and how does its dysfunction contribute to the disease process?

Answer 29

29. Elastic connective tissue is primarily involved. In atherosclerosis, the elastic fibers in the arterial walls lose their ability to stretch, leading to stiffening of the arteries. This makes it harder for blood to flow through, contributing to high blood pressure and other cardiovascular issues.

Question 30

32. Which type of collagen fiber is predominantly found in the basement membrane?
    A) Type I
    B) Type II
    C) Type III
    D) Type IV

Answer 30

32. D) Type IV
    * Rationale: Type IV collagen fibers are found in the basement membrane, providing structural support and filtration.

Question 31

30. Which of the following fibers can stretch up to 150% of their resting length without breaking?
    A) Collagen fibers
    B) Elastic fibers
    C) Reticular fibers
    D) Tropocollagen fibers

Answer 31

30. B) Elastic fibers
    * Rationale: Elastic fibers are highly stretchable and can extend up to 150% of their resting length without breaking, allowing tissues like arteries to stretch and recoil.

Question 32

31. Which of the following cells is considered multipotent and can differentiate into various cell types in response to specific stimuli?
    A) Osteoclasts
    B) Fibroblasts
    C) Mast cells
    D) Mesenchymal cells

Answer 32

31. D) Mesenchymal cells
    Rationale: Mesenchymal cells are multipotent stem cells that can differentiate into various cell types under proper stimuli, such as fibroblasts, adipocytes, and others.

Question 33

34. Elastic fibers are primarily composed of collagen.
    True / False

Answer 33

34. False
    * Rationale: Elastic fibers are composed of elastin, not collagen. They provide flexibility and elasticity to tissues like blood vessels.

Question 34

33. What is the primary component of the ground substance in connective tissue?
    A) Tropocollagen
    B) Elastin
    C) Glycosaminoglycans (GAGs)
    D) Reticulin

Answer 34

33. C) Glycosaminoglycans (GAGs)
    * Rationale: Glycosaminoglycans are a major component of the ground substance in connective tissues, contributing to its gel-like consistency and ability to resist compression.

Question 35

35. Type III collagen fibers are also known as reticular fibers and are found in organs such as the spleen and lymph nodes.
    True / False

Answer 35

35. True
    * Rationale: Type III collagen fibers, also known as reticular fibers, form the supportive framework in organs like the spleen and lymph nodes.

Question 36

36. Mast cells release histamine and heparin, which play critical roles in immune responses and inflammation.
    True / False

Answer 36

36. True
    * Rationale: Mast cells play a critical role in immune responses by releasing histamine (which causes inflammation) and heparin (which prevents blood clotting).

Question 37

38. The protein that gives bone its hardness by associating with collagen fibers is _____.

Answer 37

38. Hydroxyapatite
    * Rationale: Hydroxyapatite crystals, a form of calcium phosphate, associate with collagen fibers to give bone its hardness.

Question 38

37. _____ is a specialized connective tissue that is responsible for providing support and flexibility in areas such as the costal cartilage and trachea.

Answer 38

37. Hyaline cartilage
    * Rationale: Hyaline cartilage provides support and flexibility, found in areas like the costal cartilage of the ribs and the trachea.

Question 39

39. Which of the following are functions of the extracellular matrix (ECM) in connective tissue? (Select all that apply)
    A) Providing mechanical support
    B) Synthesizing collagen fibers
    C) Regulating cell proliferation and differentiation
    D) Facilitating nutrient and waste exchange between cells and blood vessels

Answer 39

39. A, C, D
    * Rationale: The extracellular matrix provides mechanical support, regulates cell behaviors like proliferation and differentiation, and facilitates nutrient and waste exchange.

Question 40

47. Which connective tissue cell is primarily involved in the immune defense and found abundantly in the lamina propria of the digestive tract?
    A) Fibroblast
    B) Adipocyte
    C) Plasma cell
    D) Mast cell

Answer 40

47. C) Plasma cell
    * Rationale: Plasma cells are specialized for the production of antibodies and are commonly found in the lamina propria of the digestive and respiratory tracts.

Question 41

40. Explain the difference between regular dense connective tissue and irregular dense connective tissue in terms of fiber arrangement and function.

Answer 41

40. Regular dense connective tissue has collagen fibers arranged in parallel bundles, providing tensile strength in one direction (e.g., tendons). In contrast, irregular dense connective tissue has fibers arranged in multiple directions, allowing for strength in different directions (e.g., dermis of the skin).

Question 42

41. How do fibroblasts contribute to the structural integrity of connective tissues, and what happens when they become inactive (fibrocytes)?

Answer 42

41. Fibroblasts are responsible for synthesizing the extracellular matrix, particularly collagen and elastin fibers, thus contributing to the structural integrity of connective tissues. When fibroblasts become inactive (fibrocytes), they maintain tissue but do not actively produce matrix components.

Question 43

43. A patient with liver cirrhosis is found to have significant fibrosis (scarring) in the liver. Explain how connective tissue remodeling and collagen production may be involved in this process.

Answer 43

43. In liver cirrhosis, excessive collagen production by fibroblasts (and activated hepatic stellate cells) leads to fibrosis. This results in the replacement of normal liver tissue with scar tissue, impairing liver function and contributing to the clinical symptoms of cirrhosis.

Question 44

42. A 50-year-old man presents with abnormal elasticity and hypermobility of his joints. He also has a history of frequent ligament injuries. Based on these symptoms, which connective tissue component is likely affected, and how does this affect the patient’s clinical presentation?

Answer 44

42. The likely affected component is the elastic fibers, which are responsible for providing elasticity and tensile strength to connective tissues like ligaments. Defects in elastic fibers can result in hypermobility and increased susceptibility to ligament injuries, as seen in conditions like Ehlers-Danlos syndrome.

Question 45

44. Which of the following statements about hyaline cartilage is true?
    A) It contains large amounts of elastic fibers.
    B) Chondrocytes are grouped in nests (cell nests).
    C) It is found in intervertebral discs.
    D) It lacks a perichondrium.

Answer 45

44. B) Chondrocytes are grouped in nests (cell nests).
    * Rationale: Hyaline cartilage has chondrocytes that are often found in small groups called cell nests within the matrix.

Question 46

45. Which component of bone matrix is inorganic and provides the bone with its characteristic hardness?
    A) Collagen fibers
    B) Glycoproteins
    C) Hydroxyapatite crystals
    D) Proteoglycans

Answer 46

45. C) Hydroxyapatite crystals
    * Rationale: Hydroxyapatite, a form of calcium phosphate, is the inorganic component that gives bone its hardness.

Question 47

46. During the process of endochondral ossification, the region of the developing bone responsible for longitudinal growth is the:
    A) Epiphyseal plate
    B) Diaphysis
    C) Periosteum
    D) Medullary cavity

Answer 47

46. A) Epiphyseal plate
    * Rationale: The epiphyseal plate, also known as the growth plate, is responsible for longitudinal bone growth during development.

Question 48

48. The process of membranous ossification involves the formation of bone directly from a cartilage model.
    True / False

Answer 48

48. False
    * Rationale: Membranous ossification involves the direct transformation of mesenchymal tissue into bone, without a cartilage intermediate. Endochondral ossification involves a cartilage model.

Question 49

49. Fibrocartilage lacks a perichondrium, unlike hyaline and elastic cartilage.
    True / False

Answer 49

49. True
    * Rationale: Fibrocartilage lacks a perichondrium, making it different from hyaline and elastic cartilage, which have a perichondrium.

Question 50

50. The concentric cylindrical structures found in compact bone, composed of lamellae surrounding a Haversian canal, are called _____.

Answer 50

50. Osteons (Haversian systems)
    * Rationale: Osteons are the structural units of compact bone, composed of concentric lamellae surrounding a Haversian canal.

Question 51

51. The immature cells responsible for forming new cartilage are known as _____.

Answer 51

51. Chondroblasts
    * Rationale: Chondroblasts are immature cartilage cells responsible for the synthesis and formation of the cartilage matrix.

Question 52

52. Which of the following are functions of the ground substance in connective tissue? (Select all that apply)
    A) Providing structural support to the tissue
    B) Facilitating the transport of nutrients and waste
    C) Storing large quantities of lipids
    D) Providing resistance to compressive forces
    E) Facilitating cell signaling and communication

Answer 52

52. A, B, D, E
    * Rationale: The ground substance provides structural support, facilitates nutrient exchange, resists compressive forces, and aids in cell signaling.

Question 53

53. What are the two primary types of ossification, and in what types of bones does each occur?

Answer 53

53. Membranous ossification occurs in flat bones like the skull and clavicle, where bone forms directly from mesenchymal tissue. Endochondral ossification occurs in long bones like the femur and humerus, where bone forms by replacing a cartilage model.

Question 54

54. Describe the role of osteoclasts in bone remodeling and how their activity can lead to diseases like osteoporosis.

Answer 54

54. Osteoclasts are large, multinucleated cells responsible for bone resorption. They break down bone matrix during the remodeling process, balancing the activity of osteoblasts (bone formation). Overactive osteoclasts can lead to excessive bone loss, contributing to conditions like osteoporosis, where bones become weak and fragile.

Question 55

55. A patient presents with signs of scurvy, including bleeding gums and easy bruising. Scurvy is caused by a deficiency of vitamin C, which is essential for collagen synthesis. How does this deficiency affect connective tissue, and what specific components are impaired?

Answer 55

55. Vitamin C deficiency affects collagen synthesis because it is required for the hydroxylation of proline and lysine, which are necessary for stabilizing collagen fibers. Without proper collagen formation, connective tissues lose tensile strength, leading to symptoms like bleeding gums, easy bruising, and poor wound healing.

Question 56

56. A child is diagnosed with rickets, a condition caused by vitamin D deficiency, leading to weak and soft bones. Explain how inadequate mineralization affects the connective tissue in bone and which processes are disrupted.

Answer 56

56. In rickets, a lack of vitamin D impairs the body’s ability to absorb calcium and phosphate, leading to poor bone mineralization. This results in soft, weak bones that cannot support the body’s weight properly, causing deformities and increased fracture risk. The disruption occurs in the process of bone ossification and mineral deposition.

Question 57

57. What is the primary role of reticular fibers in connective tissue?
    A) Provide tensile strength
    B) Facilitate elasticity
    C) Form a delicate support network for soft tissues
    D) Act as a storage site for calcium

Answer 57

57. C) Form a delicate support network for soft tissues
    * Rationale: Reticular fibers provide a supportive framework for soft tissues like the liver, spleen, and lymph nodes.

Question 58

58. Which of the following is a characteristic feature of elastic cartilage?
    A) Contains chondrocytes arranged in rows between bundles of collagen fibers
    B) Lacks a perichondrium
    C) Contains branching elastic fibers and returns to its original shape after being stretched
    D) Is found in intervertebral discs

Answer 58

58. C) Contains branching elastic fibers and returns to its original shape after being stretched
    * Rationale: Elastic cartilage contains a network of elastic fibers that allow it to return to its original shape after being deformed, as found in the ear and epiglottis.

Question 59

59. In bone tissue, which of the following statements about the periosteum is TRUE?
    A) It lines the medullary cavity of bones.
    B) It contains an outer fibrous layer and an inner osteogenic layer.
    C) It is composed entirely of osteoclasts and osteocytes.
    D) It is found only in compact bone, not spongy bone.

Answer 59

59. B) It contains an outer fibrous layer and an inner osteogenic layer.
    * Rationale: The periosteum is a double-layered membrane with an outer fibrous layer for protection and an inner osteogenic layer that contains osteoblasts and osteoprogenitor cells for bone growth and repair.

Question 60

60. Which type of bone cell is responsible for synthesizing the organic components of the bone matrix?
    A) Osteoclasts
    B) Osteocytes
    C) Osteoblasts
    D) Fibroblasts

Answer 60

60. C) Osteoblasts
    * Rationale: Osteoblasts synthesize the organic components of the bone matrix, including collagen

Question 61

61. Osteocytes are mature bone cells that reside in lacunae within the bone matrix and communicate with each other through canaliculi.
    True / False

Answer 61

61. True
    * Rationale: Osteocytes are mature bone cells located in lacunae, and they communicate with neighboring cells via small channels called canaliculi.

Question 62

62. The extracellular matrix of cartilage contains primarily collagen fibers and glycosaminoglycans, which provide it with tensile strength and flexibility.
    True / False

Answer 62

62. True
    Rationale: Cartilage contains collagen fibers that provide tensile strength, while glycosaminoglycans (GAGs) in the matrix give it flexibility and the ability to resist compression.

Question 63

63. Adipose tissue is considered a type of loose connective tissue and functions in energy storage, insulation, and protection of internal organs.
    True / False

Answer 63

63. True
    * Rationale: Adipose tissue, a type of loose connective tissue, plays important roles in energy storage, thermal insulation, and cushioning internal organs.

Question 64

64. The process by which mesenchymal tissue is first transformed into cartilage before being replaced by bone is called _____.

Answer 64

64. Endochondral ossification
    * Rationale: Endochondral ossification is the process where cartilage is first formed and later replaced by bone, particularly in long bones.

Question 65

65. The bone cells that function in breaking down bone tissue to release calcium into the blood are called _____.

Answer 65

65. Osteoclasts
    * Rationale: Osteoclasts are large, multinucleated cells that break down bone tissue during bone remodeling to release calcium into the bloodstream.

Question 66

66. Which of the following are characteristics of spongy bone? (Select all that apply)
    A) Contains a network of trabeculae
    B) Contains osteons with Haversian canals
    C) Has spaces between trabeculae filled with bone marrow
    D) Consists of densely packed concentric lamellae
    E) Found in the ends of long bones

Answer 66

66. A, C, E
    * Rationale: Spongy bone consists of trabeculae, with spaces filled with bone marrow, and is found at the ends of long bones.

Question 67

72. Which type of muscle tissue is striated and under voluntary control?
    ○ A) Skeletal muscle
    ○ B) Smooth muscle
    ○ C) Cardiac muscle

Answer 67

72. A) Skeletal muscle
    * Rationale: Skeletal muscle is the only type of muscle tissue that is both striated and under voluntary control.

Question 68

67. Discuss the structural differences between compact bone and spongy bone, including their locations in the skeleton and their functions.

Answer 68

67. Compact bone is dense and organized into osteons with Haversian systems, providing strength and support. It is found in the shafts of long bones. Spongy bone, found at the ends of long bones and in flat bones, is less dense and made up of trabeculae, allowing for the storage of bone marrow and lighter weight to facilitate movement.

Question 69

68. Explain how glycosaminoglycans (GAGs) in the ground substance contribute to the function of connective tissue.

Answer 69

68. Glycosaminoglycans (GAGs) are negatively charged polysaccharides in the ground substance that attract water, providing a gel-like consistency. This helps connective tissue resist compression and aids in nutrient exchange.

Question 70

69. A 45-year-old male presents with decreased flexibility and stiffness in his large arteries, and his physician diagnoses him with a condition affecting the elastic fibers of his connective tissue. Explain the role of elastic fibers in maintaining arterial flexibility and what might happen if these fibers are damaged.

Answer 70

69. Elastic fibers allow blood vessels, especially large arteries, to stretch and recoil as blood is pumped through them. When these fibers are damaged, the arteries lose their flexibility, which can lead to conditions such as hypertension and atherosclerosis, where the arteries stiffen and restrict blood flow.

Question 71

70. A child presents with abnormal bone growth and deformities, and it is determined that the epiphyseal plate has closed prematurely. How might this affect the child’s future growth, and what is the role of the epiphyseal plate in normal bone development?

Answer 71

70. The premature closure of the epiphyseal plate will halt the longitudinal growth of the bone, leading to shorter stature and potential deformities. The epiphyseal plate is responsible for lengthening bones during childhood and adolescence by allowing the continuous formation of new bone at the ends of long bones.

Question 72

71. Which of the following is NOT a property of muscle tissue?
    ○ A) Excitability
    ○ B) Contractility
    ○ C) Conductivity
    ○ D) Elasticity

Answer 72

71. C) Conductivity
    * Rationale: Conductivity refers to the ability to transmit electrical signals, which is a characteristic of nerve tissue, not muscle tissue.

Question 73

73. Which of the following is the functional unit of muscle contraction?
    ○ A) Sarcolemma
    ○ B) Sarcomere
    ○ C) Myofibril
    ○ D) Sarcoplasmic reticulum

Answer 73

73. B) Sarcomere
    * Rationale: The sarcomere is the basic contractile unit of a muscle fiber, consisting of overlapping actin and myosin filaments.

Question 74

Select All that Apply - 86. Which of the following are functions of skeletal muscle?
○ A) Movement
○ B) Posture maintenance
○ C) Heat production
○ D) Digestion
○ E) Blood vessel constriction

Answer 74

86. A) Movement, B) Posture maintenance, C) Heat production
    * Rationale: Skeletal muscles are responsible for body movement, maintaining posture against gravity, and generating heat as a byproduct of their metabolic activity.

Question 75

75. Which of the following is NOT a way muscles are named?
    ○ A) Color
    ○ B) Size
    ○ C) Location
    ○ D) Function

Answer 75

75. A) Color
    * Rationale: While muscle names often reflect factors like size, shape, location, and action, color is not a primary criterion for muscle nomenclature.

Question 76

74. What type of muscle fiber arrangement is found in the pectoralis major muscle?
    ○ A) Parallel
    ○ B) Convergent
    ○ C) Pennate
    ○ D) Circular

Answer 76

74. B) Convergent
    * Rationale: Convergent muscles have fibers that fan out from a broad origin and converge at a single insertion point, such as the pectoralis major.

Question 77

76. Describe the four properties of muscle tissue.

Answer 77

76. Four Properties of Muscle Tissue:
    * Excitability: The ability of muscle tissue to respond to stimuli from nerve impulses.
    * Contractility: The capacity of muscle tissue to shorten forcefully, generating tension and movement.
    * Extensibility: The ability of muscle tissue to stretch beyond its resting length without being damaged.
    * Elasticity: The property of muscle tissue to recoil and return to its original shape and length after being stretched.

Question 78

77. Differentiate between the origin and insertion of a muscle.

Answer 78

77. Origin vs. Insertion:
    * Origin: The attachment point of a muscle that remains relatively stationary during a muscle contraction. It’s typically the proximal attachment.
    * Insertion: The attachment point of a muscle that moves toward the origin during a muscle contraction. It’s usually the more distal attachment.

Question 79

83. Muscle fibers that are arranged at an angle to the tendon are characteristic of _____________ muscles.

Answer 79

83. Pennate
    * Rationale: Muscle fibers that are arranged at an angle to the tendon are characteristic of pennate muscles.

Question 80

78. Explain the role of the sarcoplasmic reticulum in muscle contraction.

Answer 80

78. Sarcoplasmic Reticulum in Contraction:
    * Stores Calcium Ions: The sarcoplasmic reticulum (SR) is a specialized network of membranes within muscle cells that stores a high concentration of calcium ions (Ca2+).
    * Releases Calcium: When a muscle fiber is stimulated by a nerve impulse, the SR releases Ca2+ into the sarcoplasm (muscle cell cytoplasm).
    * Calcium Triggers Contraction: This released calcium binds to regulatory proteins on the actin filaments, initiating the sliding filament mechanism of muscle contraction.
    * Pumps Calcium Back: After contraction, the SR actively pumps Ca2+ back into its storage, allowing the muscle fiber to relax.

Question 81

81. The connective tissue sheath that surrounds each individual muscle fiber is called the _____________.

Answer 81

81. Endomysium
    * Rationale: The connective tissue sheath that surrounds each individual muscle fiber.

Question 82

85. The medical term for a muscle that decreases the diameter of an opening is _____________.

Answer 82

85. Sphincter
    * Rationale: The medical term for a muscle that decreases the diameter of an opening is sphincter.

Question 83

79. Compare and contrast the structure and function of smooth muscle and cardiac muscle.

Answer 83

79. Smooth vs. Cardiac Muscle: (Content to be added based on lecture material)

Question 84

82. The thin myofilaments of a sarcomere are composed primarily of the protein _____________.

Answer 84

82. Actin
    * Rationale: The thin myofilaments of a sarcomere are composed primarily of the protein actin.

Question 85

80. What is the clinical significance of intercalated discs in cardiac muscle?

Answer 85

80. Clinical Significance of Intercalated Discs:
    * Synchronized Contractions: Intercalated discs contain gap junctions that allow for rapid electrical communication between adjacent cardiac muscle cells, ensuring that the heart contracts as a coordinated unit.
    * Structural Integrity: They also contain desmosomes that provide mechanical strength and hold the cardiac muscle cells tightly together, resisting the stress of continuous contractions.

Question 86

90. The endomysium surrounds bundles of muscle fibers called fascicles.
    True / False

Answer 86

90. False
    * Rationale: The perimysium surrounds bundles of muscle fibers, while the endomysium encases individual muscle fibers.

Question 87

84. The neurotransmitter responsible for initiating skeletal muscle contraction is _____________.

Answer 87

84. Acetylcholine
    * Rationale: The neurotransmitter responsible for initiating skeletal muscle contraction is acetylcholine.

Question 88

91. Cardiac muscle exhibits autorhythmicity, meaning it can contract without external nerve stimulation.
    True / False

Answer 88

91. True
    * Rationale: Cardiac muscle possesses intrinsic pacemaker cells that generate rhythmic electrical impulses, enabling the heart to beat without external nerve stimulation.

Question 89

89. Skeletal muscle fibers are branched and contain a single, centrally located nucleus.
    True / False

Answer 89

89. False
    * Rationale: Skeletal muscle fibers are cylindrical, multinucleated, and unbranched.

Question 90

99. Which of the following proteins is responsible for storing oxygen in muscle fibers?
    ○ A) Myoglobin
    ○ B) Actin
    ○ C) Myosin

Answer 90

99. A) Myoglobin
    * Rationale: Myoglobin is an oxygen-binding protein found in muscle tissue that stores oxygen, providing a readily available supply for muscle contraction.

Question 91

102. Compare and contrast the microscopic features of skeletal, smooth, and cardiac muscle tissues.

Answer 91

102. Microscopic Comparison of Muscle Tissues:
     * Skeletal Muscle: Multinucleated, striated, and under voluntary control, with long cylindrical fibers.
     * Smooth Muscle: Uninucleated, non-striated, and involuntary, with spindle-shaped fibers.
     * Cardiac Muscle: Uninucleated (sometimes binucleated), striated, involuntary, with branching fibers and intercalated discs.

Question 92

87. Which of the following muscles are involved in the action of a biceps curl?
    ○ A) Biceps brachii
    ○ B) Triceps brachii
    ○ C) Brachioradialis
    ○ D) Deltoid
    ○ E) Trapezius

Answer 92

87. A) Biceps brachii, C) Brachioradialis
    * Rationale: During a biceps curl, the biceps brachii is the prime mover, while the brachioradialis assists in flexion at the elbow.

Question 93

92. Myasthenia gravis is a genetic disorder that causes progressive muscle weakness and atrophy.
    True / False

Answer 93

92. False
    * Rationale: Myasthenia gravis is an autoimmune disorder, not a genetic disorder, where the immune system attacks the neuromuscular junctions, leading to muscle weakness. Duchenne muscular dystrophy is a genetic disorder.

Question 94

88. Characteristics of smooth muscle include:
    ○ A) Striated appearance
    ○ B) Presence of intercalated discs
    ○ C) Involuntary control
    ○ D) Fusiform shaped cells
    ○ E) Multinucleated cells

Answer 94

88. C) Involuntary control, D) Fusiform shaped cells
    * Rationale: Smooth muscle is not under conscious control and is characterized by its spindle-shaped (fusiform) cells.

Question 95

94. A 35-year-old male patient presents with complaints of muscle weakness and fatigue, particularly in his eyelids and facial muscles. He reports that these symptoms worsen as the day progresses. Based on his symptoms, the physician suspects myasthenia gravis.

• 94.1. Describe the underlying cause of myasthenia gravis and explain why it leads to muscle weakness.
• 94.2. What are some other symptoms that this patient might experience?

Answer 95

94.1 Myasthenia Gravis Cause:
* Myasthenia gravis is an autoimmune disease in which the body’s immune system mistakenly targets and attacks acetylcholine receptors at the neuromuscular junction. This attack disrupts the transmission of nerve impulses to muscle fibers, leading to muscle weakness and fatigue.
94.2 Other Symptoms:
* Drooping eyelids (ptosis)
* Double vision (diplopia)
* Difficulty swallowing (dysphagia)
* Slurred speech (dysarthria)
* Shortness of breath (dyspnea)

Question 96

101. Describe the arrangement of muscle fibers in a bipennate muscle and give an example of a bipennate muscle in the human body.

Answer 96

101. Bipennate Muscle:
     * Arrangement: In a bipennate muscle, the muscle fibers are arranged on both sides of a central tendon, resembling a feather. This arrangement allows for more muscle fibers to attach to the tendon, generating greater force compared to parallel muscles.
     * Example: The rectus femoris, one of the quadriceps muscles in the thigh, is an example of a bipennate muscle.

Question 97

93. Dense bodies in smooth muscle function similarly to Z discs in skeletal muscle.
    True / False

Answer 97

93. True
    * Rationale: Dense bodies in smooth muscle act as anchoring points for actin filaments, similar to the role of Z discs in organizing sarcomeres in skeletal and cardiac muscle.

Question 98

95. Which of the following muscle types is responsible for the peristaltic movements of the digestive tract?
    ○ A) Skeletal muscle
    ○ B) Smooth muscle
    ○ C) Cardiac muscle

Answer 98

95. B) Smooth muscle
    * Rationale: Smooth muscle is responsible for the involuntary, rhythmic contractions known as peristalsis that propel food through the digestive tract.

Question 99

96. Which of the following connective tissue components surrounds a fascicle?
    ○ A) Epimysium
    ○ B) Perimysium
    ○ C) Endomysium

Answer 99

96. B) Perimysium
    * Rationale: The perimysium is a connective tissue layer that bundles muscle fibers into groups called fascicles.

Question 100

97. A triad in a skeletal muscle fiber is composed of:
    ○ A) One T-tubule and two sarcomeres
    ○ B) Two terminal cisternae and one T-tubule
    ○ C) One terminal cisterna and two mitochondria

Answer 100

97. B) Two terminal cisternae and one T-tubule
    * Rationale: A triad is a structure formed by a T-tubule, which is an invagination of the sarcolemma, flanked by two terminal cisternae of the sarcoplasmic reticulum. This arrangement allows for rapid and coordinated muscle fiber activation.

Question 101

100. Explain the difference between a “fixator” muscle and a “synergist” muscle, providing examples of each.

Answer 101

100. Fixator vs. Synergist Muscles:
     * Fixator Muscle: A fixator muscle stabilizes the origin of a prime mover muscle, ensuring that the prime mover can exert its full force on the insertion point. Fixators prevent unwanted movement at a joint. Example: During a biceps curl, the rotator cuff muscles act as fixators to stabilize the shoulder joint, allowing the biceps brachii to effectively flex the elbow.
     * Synergist Muscle: A synergist muscle assists the prime mover in performing a movement. It may help to refine the movement, provide additional force, or stabilize the joint. Example: In a biceps curl, the brachioradialis acts as a synergist, assisting the biceps brachii in flexing the elbow.

Question 102

98. Which of the following statements regarding smooth muscle is TRUE?
    ○ A) Smooth muscle fibers contain multiple, peripherally located nuclei.
    ○ B) Smooth muscle is responsible for voluntary movements of the limbs.
    ○ C) Smooth muscle can exhibit autorhythmicity, allowing for spontaneous contractions.

Answer 102

98. C) Smooth muscle can exhibit autorhythmicity, allowing for spontaneous contractions.
    * Rationale: Smooth muscle, particularly visceral smooth muscle, can generate its own rhythmic contractions without external nerve stimulation.

Question 103

103. The ____________ is a thin sheath of fibrous connective tissue that helps connect muscles to bones.

Answer 103

103. Aponeurosis
     * Rationale: The aponeurosis is a thin sheath of fibrous connective tissue that helps connect muscles to bones.

Question 104

104. The protein ____________ is found in thick myofilaments and plays a crucial role in muscle contraction.

Answer 104

104. Myosin
     * Rationale: The protein myosin is found in thick myofilaments and plays a crucial role in muscle contraction.

Question 105

105. Smooth muscle is found in the walls of ____________ organs such as the stomach and intestines.

Answer 105

105. Hollow
     * Rationale: Smooth muscle is found in the walls of hollow organs such as the stomach and intestines.

Question 106

Select All that Apply- 106. Which of the following statements correctly describe the characteristics of cardiac muscle tissue?
○ A) It is striated and involuntary.
○ B) It contains intercalated discs that allow for synchronized contractions.
○ C) Cardiac muscle fibers are multinucleated.
○ D) Cardiac muscle relies solely on external nerve stimulation for contraction.
○ E) Cardiac muscle is responsible for the pumping action of the heart.

Answer 106

106. A) It is striated and involuntary, B) It contains intercalated discs that allow for synchronized contractions., E) Cardiac muscle is responsible for the pumping action of the heart.
     * Rationale: Cardiac muscle is striated due to the arrangement of its contractile proteins. It is involuntary, meaning it contracts without conscious control. Intercalated discs are unique features of cardiac muscle that facilitate rapid electrical communication between cells, ensuring coordinated contractions for effective pumping of blood.

Question 107

Select All that Apply - 107. Which of the following muscle disorders are primarily genetic in origin?
○ A) Myasthenia gravis
○ B) Duchenne muscular dystrophy
○ C) Tetanus

Answer 107

107. B) Duchenne muscular dystrophy
     * Rationale: Duchenne muscular dystrophy is a genetic disorder caused by mutations in the dystrophin gene, leading to muscle weakness and degeneration. While myasthenia gravis is an autoimmune disorder, tetanus is caused by a bacterial infection.

Question 108

109. Skeletal muscle is responsible for maintaining body temperature through shivering.
     True / False

Answer 108

109. True
     * Rationale: Skeletal muscle contractions, including those involved in shivering, generate heat, contributing to the maintenance of body temperature.

Question 109

110. The origin of a muscle is typically the more movable attachment point during contraction.
     True / False

Answer 109

110. False
     * Rationale: The origin of a muscle is the less movable attachment point during contraction. The insertion is the more movable point, which is pulled towards the origin during muscle shortening.

Question 110

108. The H zone of a sarcomere contains both actin and myosin filaments.
     True / False

Answer 110

108. False
     * Rationale: The H zone in the center of a sarcomere contains only thick filaments (myosin). Thin filaments (actin) extend from the Z lines to the edges of the H zone but do not overlap with myosin in this region.

Question 111

111. A 40-year-old female patient complains of chronic constipation and abdominal discomfort. After ruling out other possibilities, the physician suspects a potential issue with the smooth muscle function in her digestive tract.
     * 111.1 Explain how the structure and function of smooth muscle contribute to the movement of food through the digestive system.
     * 111.2 What are some potential causes of smooth muscle dysfunction in the digestive tract? (This question may require information from outside the provided sources.)

Answer 111

111.1 Smooth Muscle and Digestion:
* Peristalsis: Smooth muscle in the walls of the digestive tract contracts and relaxes in a coordinated wave-like pattern called peristalsis. This propulsive action moves food along the digestive tract.
* Segmentation: In addition to peristalsis, smooth muscle also undergoes rhythmic contractions known as segmentation. Segmentation mixes food with digestive enzymes and aids in absorption by bringing digested nutrients into contact with the intestinal lining.
111.2 Potential Causes of Smooth Muscle Dysfunction in the Digestive Tract:
* Nerve Damage: Damage to the nerves controlling smooth muscle can disrupt peristalsis and lead to digestive issues.
* Muscle Diseases: Conditions affecting smooth muscle, such as muscular dystrophies, can impair gastrointestinal motility.
* Medications: Some medications can interfere with smooth muscle function, causing constipation or diarrhea.
* Electrolyte Imbalances: Imbalances in electrolytes, such as potassium and calcium, can affect smooth muscle contractility.
* Hormonal Imbalances: Hormones like thyroid hormone can influence smooth muscle activity in the digestive tract.
* Chronic Stress: Prolonged stress can disrupt the nervous system’s control of digestion, affecting smooth muscle function.