BIOL 252 Human Anatomy & Physiology II w/Lab
Final Exam Questions and Answers Summary |
Portage Learning | For Better Grades A+ Pass
CONNECTIVE TISSUE & MUSCLE
Q1. What is the role of glycosaminoglycans (GAGs) in connective tissue ground substance?
Answer: They attract positive ions and water.
Rationale: GAGs are negatively charged molecules that bind ions such as Na⁺, which in turn
attract water, giving the ground substance its viscosity and cushioning properties.
Q2. What is a myofibril?
Answer: The contractile organelle of a muscle fiber made of organized proteins.
Rationale: Myofibrils contain actin and myosin arranged in sarcomeres, allowing muscle
contraction.
Q3. What is the endomysium?
Answer: Connective tissue surrounding an individual muscle fiber.
Rationale: The endomysium provides structural support and helps transmit contractile force.
Q4. Which muscle type has fused cells without gap junctions?
Answer: Skeletal muscle
Rationale: Skeletal muscle fibers are multinucleated from developmental fusion and rely on
neural input rather than gap junctions.
Q5. Which features characterize smooth muscle?
Answer: Loosely organized myofibrils, sustained tension, gap junctions, and visceral location.
Rationale: These traits allow smooth muscle to contract slowly and continuously in organs such
as the intestines and blood vessels.
, Q6. What structures connect cardiac muscle cells?
Answer: Intercalated discs
Rationale: Intercalated discs contain gap junctions and desmosomes, enabling synchronized
contraction and mechanical strength.
Q7. Which connective tissue cells secrete extracellular matrix proteins?
Answer: Fibroblasts
Rationale: Fibroblasts synthesize collagen, elastin, reticular fibers, and GAGs.
Q8. Which connective tissue fiber resists stretching?
Answer: Collagen
Rationale: Collagen fibers are strong and tensile, providing resistance to pulling forces.
MUSCLE CONTRACTION & PHYSIOLOGY
Q9. What is the function of the sarcoplasmic reticulum (SR)?
Answer: Stores and releases calcium ions (Ca²⁺).
Rationale: Calcium release from the SR initiates muscle contraction by exposing actin binding
sites.
Q10. What protein blocks myosin binding sites on actin?
Answer: Tropomyosin
Rationale: Tropomyosin prevents contraction until Ca²⁺ binds troponin.
Q11. How does Ca²⁺ enable muscle contraction?
Answer: Ca²⁺ binds to troponin, shifting tropomyosin away from actin binding sites.
Rationale: This exposes actin sites, allowing cross-bridge formation.
Final Exam Questions and Answers Summary |
Portage Learning | For Better Grades A+ Pass
CONNECTIVE TISSUE & MUSCLE
Q1. What is the role of glycosaminoglycans (GAGs) in connective tissue ground substance?
Answer: They attract positive ions and water.
Rationale: GAGs are negatively charged molecules that bind ions such as Na⁺, which in turn
attract water, giving the ground substance its viscosity and cushioning properties.
Q2. What is a myofibril?
Answer: The contractile organelle of a muscle fiber made of organized proteins.
Rationale: Myofibrils contain actin and myosin arranged in sarcomeres, allowing muscle
contraction.
Q3. What is the endomysium?
Answer: Connective tissue surrounding an individual muscle fiber.
Rationale: The endomysium provides structural support and helps transmit contractile force.
Q4. Which muscle type has fused cells without gap junctions?
Answer: Skeletal muscle
Rationale: Skeletal muscle fibers are multinucleated from developmental fusion and rely on
neural input rather than gap junctions.
Q5. Which features characterize smooth muscle?
Answer: Loosely organized myofibrils, sustained tension, gap junctions, and visceral location.
Rationale: These traits allow smooth muscle to contract slowly and continuously in organs such
as the intestines and blood vessels.
, Q6. What structures connect cardiac muscle cells?
Answer: Intercalated discs
Rationale: Intercalated discs contain gap junctions and desmosomes, enabling synchronized
contraction and mechanical strength.
Q7. Which connective tissue cells secrete extracellular matrix proteins?
Answer: Fibroblasts
Rationale: Fibroblasts synthesize collagen, elastin, reticular fibers, and GAGs.
Q8. Which connective tissue fiber resists stretching?
Answer: Collagen
Rationale: Collagen fibers are strong and tensile, providing resistance to pulling forces.
MUSCLE CONTRACTION & PHYSIOLOGY
Q9. What is the function of the sarcoplasmic reticulum (SR)?
Answer: Stores and releases calcium ions (Ca²⁺).
Rationale: Calcium release from the SR initiates muscle contraction by exposing actin binding
sites.
Q10. What protein blocks myosin binding sites on actin?
Answer: Tropomyosin
Rationale: Tropomyosin prevents contraction until Ca²⁺ binds troponin.
Q11. How does Ca²⁺ enable muscle contraction?
Answer: Ca²⁺ binds to troponin, shifting tropomyosin away from actin binding sites.
Rationale: This exposes actin sites, allowing cross-bridge formation.
