Musculoskeletal System

What type of muscle is under voluntary control and innervated by the somatic nervous system?

Skeletal Muscle

Describe skeletal muscle

voluntary and multinucleated and striated

Describe smooth muscle

involuntary and non-striated and uninucleated

Describe cardiac muscle

involuntary, striated, and uninucleated

What is the basic functional unit of skeletal muscle called?

Sarcomere

What type of muscle fibers rely on oxidative phosphorylation to make ATP?

Red Fibers

What are the characteristics of smooth muscle?

Involuntary motion, no striations, innervated by the autonomic nervous system.

What defines the boundaries of each sarcomere?

Z lines

What is the region of the sarcomere that contains only myelin?

The H zone (thick filaments)

What region of the sarcomere contains only actin?

I zone

What is the region of the sarcomere that is the middle?

M line

What is the role of titin in muscle structure?

Acts as a spring and anchors actin/myosin to prevent excessive stretch.

What happens during the power stroke of muscle contraction?

Myosin pulls on actin, shortening the sarcomere.

What is the result of rigor mortis in terms of muscle contraction?

Permanent contraction due to lack of ATP to release myosin from actin.

What does acetylcholinesterase do during muscle relaxation?

Takes up acetylcholine at the neuromuscular junction.

What is calcium's role in muscle contraction?

Calcium binds to troponin, twisting tropomyosin , causing a conformational change that allows myosin and actin interaction.

What are the two types of bone tissue?

Compact Bone and Spongey (Cancellous) Bone.

What type of joints are formed by sutures?

Immovable Joints.

What are the functions of red bone marrow?

Hematopoiesis.

What type of muscle fibers have fewer mitochondria and rely mainly on glycolysis?

Fast Twitch White Fibers.

What is the difference between axial and appendicular skeletal systems?

Axial includes the skull and vertebral column, while appendicular includes limb bones and girdles.

What type of connective tissue is cartilage primarily composed of?

Chondrin.

What occurs during depolarization of the sarcolemma?

The sarcolemma transmits the action potential to T tubules.

What is meant by muscle fatigue?

A state where muscles cannot perform effectively due to energy depletion and lactic acid accumulation.

What connection does a tendon provide?

Connection of muscle to bone.

What is the role of the vagus nerve in heart function?

Slows heart rate.

What is released from the sarcoplasmic reticulum during muscle contraction?

Calcium ions.

What molecule (s) are released during power stroke of myosin?

ADP and P

Is cartilage vascular or avascular?

vascular

How does cartilage exchange nutrients and waste?

diffusion

What are lacunae in bone?

small spaces that contain osteocytes, allowing for communication and nutrient exchange.

What are caniculi in bone?

tiny channels that connect lacunae and facilitate nutrient and waste exchange between osteocytes.

What are Haversian canals in bones?

central channels in compact bone that contain blood vessels and nerves

The long shaft of bone is called

the diaphysis.

The ends of bones are called

epiphyses.

What causes the release of myosin from actin?

The binding of a new ATP molecule to myosin.

What causes the recocking of the myosin head?

ATP hydrolysis

What is the main function of osteoclasts?

To absorb bone and increase serum calcium.

What is the name of the muscle cell in the heart?

Cardiomyocyte.

What role do troponin and tropomyosin play in muscle contraction?

Troponin binds calcium, causing tropomyosin to shift and expose binding sites on actin for myosin.

What is the significance of ADP and inorganic phosphate (Pi) in muscle contraction?

ADP and Pi are released when myosin bends after the power stroke, allowing a new ATP to bind.

What is the role of ATP in muscle contraction?

ATP binds to myosin, allowing myosin to detach from actin and re-cock for another contraction.

What is the power stroke in muscle contraction?

The power stroke is the action where myosin pulls on actin, causing the sarcomere to shorten.

How does calcium influence the process of muscle contraction?

Calcium binds to troponin, leading to a conformational change that shifts tropomyosin and facilitates myosin-actin interaction.

What is myoglobin?

Myoglobin is a protein found in muscle tissue that binds oxygen and provides a reserve supply of oxygen for muscle cells, facilitating aerobic respiration.

What is significance of creatinine phosphate?

donates a phosphate group to ADP to rapidly regenerate ATP during short bursts of intense activity

What is the significance of creatinine in muscle metabolism?

Creatinine is a waste product of creatine phosphate, and its levels in the blood can indicate muscle mass and kidney function.

What regions of the sarcomere are affected by contraction?

During contraction, the I band shortens, the H zone disappears, and the A band remains the same length.

What is the effect of contraction on Z lines?

Z lines move closer together during muscle contraction.