Hondros Bio 253 exam 2 Questions With Complete Solutions
Course
BIO 253
Question1: What are the two major divisions of the skeletal system?
Answer: The skeletal system is divided into two major parts:
Axial Skeleton: Includes the skull, vertebral column, sternum, and ribs.
Appendicular Skeleton: Comprises the limbs and girdles (pectoral and pelvic girdles).
Question: What is the shaft of a long bone called?
Answer2: The shaft of a long bone is called the diaphysis. It is the elongated, central portion of
the bone.
Question3: Where does longitudinal bone growth occur?
Answer: Longitudinal bone growth occurs at the epiphyseal disc (also known as the growth
plate), which is a layer of cartilage located between the epiphysis and diaphysis of long bones.
Question4: Which cells are responsible for bone formation?
Answer: Osteoblasts are the cells responsible for bone formation. They secrete the bone matrix
and are involved in the mineralization process.
Question5: What is the site of blood cell production in bones?
Answer: Blood cell production occurs in the red bone marrow, which is found within the cavities
of certain bones, such as the pelvis, ribs, sternum, and vertebrae.
,Question6: What is the tough outer covering of a bone called?
Answer: The tough outer covering of a bone is called the periosteum. It is a dense layer of
vascular connective tissue enveloping the bones except at the surfaces of the joints.
Question7: What term describes the enlarged end of a long bone?
Answer: The enlarged end of a long bone is referred to as the epiphysis. Each long bone has a
proximal and distal epiphysis.
Question8: What type of bone is characterized by a porous, honeycomb structure?
Answer: Spongy bone, also known as cancellous bone, has a porous, honeycomb-like structure.
It is typically found at the ends of long bones and within the interior of other bones.
Question9: What is an osteon?
Answer: An osteon, or Haversian system, is the fundamental functional unit of compact bone. It
consists of concentric layers (lamellae) of calcified matrix surrounding a central canal containing
blood vessels and nerves.
Question10: Which cells are involved in bone resorption?
Answer: Osteoclasts are large, multinucleated cells responsible for bone resorption. They break
down bone tissue by secreting acids and enzymes, a process essential for bone remodeling and
calcium homeostasis.
Question11: What is the hollow center of a long bone called?
,Answer: The hollow center of a long bone is known as the medullary cavity. In adults, it
primarily contains yellow bone marrow, which is rich in fat cells.
Question12: What is the composition and function of the epiphyseal disc?
Answer: The epiphyseal disc is composed of hyaline cartilage and is located between the
epiphysis and diaphysis of long bones. It is responsible for the longitudinal growth of bones
during childhood and adolescence.
Question13: How does osteoclastic activity affect bones?
Answer: Increased osteoclastic activity leads to bone resorption, where bone tissue is broken
down, releasing minerals like calcium into the bloodstream. This process decreases bone mass
and is a normal part of bone remodeling.
Question14: What are the potential consequences of red bone marrow suppression?
Answer: Suppression of red bone marrow can lead to a decrease in the production of blood cells,
resulting in conditions such as anemia (low red blood cells), increased risk of infection (low
white blood cells), and impaired blood clotting (low platelets).
Question15: What is the role of the periosteum in bone health?
Answer: The periosteum serves several functions:
Protection: It protects the bone surface.
Nourishment: Contains blood vessels that supply nutrients to the bone tissue.
Attachment Point: Provides a surface for the attachment of tendons and ligaments.
, Growth and Repair: Contains osteogenic cells that contribute to bone growth and repair.
16. What are the three types of muscle tissue?
Answer:
Skeletal muscle: Voluntary, striated, attached to bones, responsible for movement.
Cardiac muscle: Involuntary, striated, found in the heart, responsible for pumping blood.
Smooth muscle: Involuntary, non-striated, found in internal organs such as the digestive
tract and blood vessels.
17. What is the basic contractile unit of a muscle fiber?
Answer: The sarcomere is the basic contractile unit of a muscle fiber. It consists of actin (thin)
and myosin (thick) filaments, which slide past each other during muscle contraction.
18. What neurotransmitter is released at the neuromuscular junction?
Answer: Acetylcholine (ACh) is released at the neuromuscular junction, where it binds to
receptors on the muscle fiber to trigger contraction.
19. What is the role of calcium in muscle contraction?
Answer: Calcium binds to troponin, causing a conformational change that moves tropomyosin
away from the binding sites on actin, allowing myosin to bind and initiate contraction.
20. What is ATP's role in muscle contraction?
Answer: ATP is required for:
Cross-bridge cycling (attachment and detachment of myosin from actin).
Pumping calcium back into the sarcoplasmic reticulum for muscle relaxation.
Providing energy for overall muscle function.
21. What are the three types of muscle contractions?
Answer:
Course
BIO 253
Question1: What are the two major divisions of the skeletal system?
Answer: The skeletal system is divided into two major parts:
Axial Skeleton: Includes the skull, vertebral column, sternum, and ribs.
Appendicular Skeleton: Comprises the limbs and girdles (pectoral and pelvic girdles).
Question: What is the shaft of a long bone called?
Answer2: The shaft of a long bone is called the diaphysis. It is the elongated, central portion of
the bone.
Question3: Where does longitudinal bone growth occur?
Answer: Longitudinal bone growth occurs at the epiphyseal disc (also known as the growth
plate), which is a layer of cartilage located between the epiphysis and diaphysis of long bones.
Question4: Which cells are responsible for bone formation?
Answer: Osteoblasts are the cells responsible for bone formation. They secrete the bone matrix
and are involved in the mineralization process.
Question5: What is the site of blood cell production in bones?
Answer: Blood cell production occurs in the red bone marrow, which is found within the cavities
of certain bones, such as the pelvis, ribs, sternum, and vertebrae.
,Question6: What is the tough outer covering of a bone called?
Answer: The tough outer covering of a bone is called the periosteum. It is a dense layer of
vascular connective tissue enveloping the bones except at the surfaces of the joints.
Question7: What term describes the enlarged end of a long bone?
Answer: The enlarged end of a long bone is referred to as the epiphysis. Each long bone has a
proximal and distal epiphysis.
Question8: What type of bone is characterized by a porous, honeycomb structure?
Answer: Spongy bone, also known as cancellous bone, has a porous, honeycomb-like structure.
It is typically found at the ends of long bones and within the interior of other bones.
Question9: What is an osteon?
Answer: An osteon, or Haversian system, is the fundamental functional unit of compact bone. It
consists of concentric layers (lamellae) of calcified matrix surrounding a central canal containing
blood vessels and nerves.
Question10: Which cells are involved in bone resorption?
Answer: Osteoclasts are large, multinucleated cells responsible for bone resorption. They break
down bone tissue by secreting acids and enzymes, a process essential for bone remodeling and
calcium homeostasis.
Question11: What is the hollow center of a long bone called?
,Answer: The hollow center of a long bone is known as the medullary cavity. In adults, it
primarily contains yellow bone marrow, which is rich in fat cells.
Question12: What is the composition and function of the epiphyseal disc?
Answer: The epiphyseal disc is composed of hyaline cartilage and is located between the
epiphysis and diaphysis of long bones. It is responsible for the longitudinal growth of bones
during childhood and adolescence.
Question13: How does osteoclastic activity affect bones?
Answer: Increased osteoclastic activity leads to bone resorption, where bone tissue is broken
down, releasing minerals like calcium into the bloodstream. This process decreases bone mass
and is a normal part of bone remodeling.
Question14: What are the potential consequences of red bone marrow suppression?
Answer: Suppression of red bone marrow can lead to a decrease in the production of blood cells,
resulting in conditions such as anemia (low red blood cells), increased risk of infection (low
white blood cells), and impaired blood clotting (low platelets).
Question15: What is the role of the periosteum in bone health?
Answer: The periosteum serves several functions:
Protection: It protects the bone surface.
Nourishment: Contains blood vessels that supply nutrients to the bone tissue.
Attachment Point: Provides a surface for the attachment of tendons and ligaments.
, Growth and Repair: Contains osteogenic cells that contribute to bone growth and repair.
16. What are the three types of muscle tissue?
Answer:
Skeletal muscle: Voluntary, striated, attached to bones, responsible for movement.
Cardiac muscle: Involuntary, striated, found in the heart, responsible for pumping blood.
Smooth muscle: Involuntary, non-striated, found in internal organs such as the digestive
tract and blood vessels.
17. What is the basic contractile unit of a muscle fiber?
Answer: The sarcomere is the basic contractile unit of a muscle fiber. It consists of actin (thin)
and myosin (thick) filaments, which slide past each other during muscle contraction.
18. What neurotransmitter is released at the neuromuscular junction?
Answer: Acetylcholine (ACh) is released at the neuromuscular junction, where it binds to
receptors on the muscle fiber to trigger contraction.
19. What is the role of calcium in muscle contraction?
Answer: Calcium binds to troponin, causing a conformational change that moves tropomyosin
away from the binding sites on actin, allowing myosin to bind and initiate contraction.
20. What is ATP's role in muscle contraction?
Answer: ATP is required for:
Cross-bridge cycling (attachment and detachment of myosin from actin).
Pumping calcium back into the sarcoplasmic reticulum for muscle relaxation.
Providing energy for overall muscle function.
21. What are the three types of muscle contractions?
Answer:
