Lecture 7,17, Musles

What components make up the axial skeleton?

Skull and associated bones, thoracic cage, vertebral column, and supplemental cartilages.

What is a major function of the axial skeleton?

Support and protect the brain, spinal cord, and organs in trunk body cavities.

How many bones are in the skull?

22.

How many cranial bones are in the cranium?

8.

What is a primary function of the facial bones?

Provide attachment points for muscles that control facial expression and manipulate food.

What suture attaches the frontal bone to the parietal bones?

Coronal suture.

What is a function of the paranasal sinuses?

Lighten skull weight and allow the voice to resonate.

Where are the tiny bones of hearing located?

Inside the temporal bone.

What is the largest fontanel, commonly called the 'soft spot'?

Anterior fontanel.

How many bones compose the vertebral column?

26.

How many vertebrae are typically in the cervical region?

7.

Which spinal curvature develops before birth?

Thoracic curve.

What ability is primarily connected to the development of the lumbar curve?

Stand.

What is an exaggerated thoracic curvature called?

Kyphosis.

What forms the vertebral canal that encloses the spinal cord?

Vertebral foramina of successive vertebrae.

What is the first cervical vertebra called?

Atlas.

At what age do the five fused vertebrae of the sacrum typically complete fusion?

Age 25-30.

In which group is the curvature of the sacrum more pronounced?

Males.

What is the thoracic cage composed of?

Thoracic vertebrae, ribs, and sternum.

What is the trapezoid-shaped superior portion of the sternum called?

Manubrium.

What are ribs 11 and 12 known as?

Vertebral ribs (floating ribs).

What is a primary role of the appendicular skeleton?

Permit most body movements.

What two bones form the pectoral girdle?

Clavicle and scapula.

What type of action do the humerus and ulna primarily form?

Hinge action (flex and extend).

What three bones fuse to form each hip bone of the pelvic girdle?

Ilium, ischium, and pubis.

What is the fibrocartilage pad connecting the right and left pubic bones called?

Pubic symphysis.

Which bone in the lower leg bears the body's weight?

Tibia.

What are the fibrocartilage pads in the knee called?

Menisci.

What two bones connect to form the longitudinal arch of the foot?

Calcaneus to distal part of metatarsal bones.

Which bone in the ankle transmits body weight to the ground?

Calcaneus.

Which of the following is NOT one of the three primary locations where muscles are found?

Inside bones

What is the fundamental action performed by muscles?

To contract (shorten)

Skeletal muscle cells are specifically referred to as?

Muscle fibers

A defining characteristic of skeletal muscle cells is that they are?

Long tubes, multinucleate, and with striations

What gives skeletal muscle its 'striped' or banded appearance?

Striations

Cardiac muscle cells are distinguished by being?

Striated, branched, and connected by intercalated discs

Which type of muscle tissue is found in the walls of hollow organs and is characterized as nonstriated?

Smooth muscle

The organization of muscle tissue, from a bundle of cells to the functional unit of contraction, is best described as?

Fascicle, muscle fiber, myofibril, sarcomere

Which connective tissue layer covers the entire muscle organ?

Epimysium

Bundles of muscle fibers are referred to as?

Fascicles

The connective tissue that covers each individual muscle fiber is the?

Endomysium

What is identified as the smallest functional unit of a skeletal muscle fiber?

Sarcomere

In a sarcomere, thin filaments are primarily composed of which protein?

Actin

The darker region of a sarcomere that extends the length of the thick filaments and includes the zone of overlap is known as the?

A band

The protein that constitutes the thick filaments in a sarcomere is?

Myosin

Which structure is located at each end of a sarcomere and is connected to the thick filaments by strands of titin?

Z line

When a muscle fiber is relaxed, the H band contains only?

Thick filaments

Muscle contractions generate heat, contributing to which skeletal muscle function?

Maintain body temperature

Skeletal muscles are attached to bones or skin through fibrous connective tissues. Rope-like structures performing this attachment are called?

Tendons

When muscles shorten, they pull which end towards the non-moving end?

Insertion to origin

Muscles typically work in opposing (antagonistic) groups, meaning when one muscle contracts, the other in the pair must?

Relax

According to the sources, which of the following is a common cause of muscle cramps?

Overworking muscles

Skeletal muscles are classified as organs because they contain?

Many bundled cells, wrapped in connective tissues, blood vessels, and nerves

A single skeletal muscle fiber can be very long, with some reaching lengths of up to?

60 cm

Each skeletal muscle fiber is described as containing hundreds of nuclei, meaning it is?

Multinucleate

The 'Zone of overlap' within a sarcomere explicitly contains?

Both thick and thin filaments

What is the primary function of the M line in a sarcomere?

To connect central portions of the thick filaments

During muscle contraction, myosin heads bind and pull what to the middle of the sarcomere?

Actin

Muscle contraction requires a significant amount of ATP energy, and therefore relies heavily on the presence of numerous?

Mitochondria

Which of the following is a specific function of skeletal muscle tissue related to the digestive and urinary tracts?

Guarding entrances and exits