BIO 1121 CSCC Unit 2 Exam

Identify the bone that contains the most functioning marrow for hematopoiesis.

Femur

Classify the patella according to its bone type.

Sesamoid bone

Identify the type of connective tissue that forms ligaments and tendons.

Dense regular connective tissue

Identify the tissue composed of trabeculae, providing multidirectional support deep within bones.

Spongy bone (cancellous bone)

Determine the specific cell responsible for remodeling bone.

Osteoclast

Identify the cell that secretes osteoid and traps calcium and phosphorus to mineralize new bone.

Osteoblast

In the osteons of compact bone, identify the structure that contains the living osteocytes.

Lacunae

What is a unique feature of endochondral bone formation compared to other forms?

Cartilage model replaced by bone

Recognize the characteristic of appositional bone growth and how it affects bone structure.

Increases bone width

During endochondral ossification, which part of the bone ossifies first?

Diaphysis

Identify the hormone(s) that stimulate osteoblasts in the epiphyseal plate, leading to the formation of the epiphyseal line.

Growth hormone and sex hormones (estrogen/testosterone)

Explain the relationship between calcium and vitamin D in bone health.

Vitamin D enhances calcium absorption

Identify the risk factors associated with osteoporosis.

Age, gender (female), low calcium intake, lack of physical activity

Name the bone disorder caused by vitamin D deficiency during childhood.

Rickets

Classify the joint formed by the fibrocartilage in the pubic symphysis that stretches during childbirth.

Cartilaginous joint (symphysis)

Identify the components of a diarthroses joint, such as the knee.

Synovial fluid, articular cartilage, joint capsule

Identify the congenital condition characterized by an S-shaped curvature of the thoracic vertebral column.

Scoliosis

Which neurons conduct action potentials away from the CNS to muscles?

Motor neurons

Identify the cell type that supports the functioning of the nervous system.

Glial cells (neuroglia)

What is the main function of myelinated axons in neuron activity?

Speed up action potential conduction

Identify the part of the neuron that receives stimuli or neurotransmitters.

Dendrites

Name the condition caused by chronic progressive demyelination of CNS neurons due to an autoimmune attack.

Multiple sclerosis

Which tissues are both irritable and excitable?

Nervous and muscle tissues

What is the typical resting membrane potential value for neurons?

-70 mV

What is the role of Na+/K+ pumps in neurons?

Maintain resting membrane potential by pumping Na+ out and K+ in

Identify the function of ligand-gated Na+ channels in neurons.

Trigger depolarization when neurotransmitters bind

Explain the role of K+ channels during repolarization in neuron action potentials.

Allow K+ to exit, restoring negative charge

What is the critical threshold voltage required to trigger an action potential?

-55 mV

Describe the result of an action potential in a pre-synaptic neuron that opens K+ channels, moving the post-synaptic neuron away from the threshold.

Hyperpolarization of the post-synaptic neuron

Identify what occurs when K+ channels open down the length of a neuron.

Repolarization of the neuron

Define a graded (local) potential and how it stimulates a neuron without triggering an action potential.

Small local change that may not reach threshold for action potential

What is the final event during an action potential?

Return to resting membrane potential

Describe the period when no stimulus can trigger a neuron to fire another action potential.

Absolute refractory period

What function of the muscular system is directly related to tendons connecting muscles to bones?

Movement of bones

Define the muscle attachment that moves during contraction.

Insertion

Which protein pulls actin towards the center of the sarcomere during muscle contraction?

Myosin

Where is calcium stored when a muscle cell is at rest?

Sarcoplasmic reticulum

Identify the repeating unit of a skeletal muscle cell where contraction occurs.

Sarcomere

What is the primary cause of most muscular dystrophies, including Duchenne's MD?

Genetic mutation

Identify the muscle cell membrane that contains T tubules.

Sarcolemma

What is the first event that occurs in the sequence of muscle contraction?

Action potential travels down the neuron

Explain how calcium binding to troponin triggers muscle contraction.

Exposes myosin-binding sites on actin

What ion couples muscle cell excitation with contraction?

Calcium (Ca2+)

What causes the power stroke during cross-bridge cycling in muscle contraction?

Myosin head pivots and pulls actin filament

Define summation in the context of muscle tension and stimulus frequency.

Increased tension due to repeated stimuli

During which phase of muscle activity does depolarization and increased tension occur?

Contraction phase

Identify the substance responsible for storing ATP in skeletal muscle cells.

Creatine phosphate

What substance is produced in greater quantity by muscle during oxygen deficiency?

Lactic acid

Which type of muscle fiber is built for speed but not endurance?

Fast-twitch fibers

Define the injury commonly referred to as a "pulled muscle."

Muscle strain