Muscle and Skeleton Anatomy Lecture Notes

These flashcards cover key terms and concepts related to the appendicular skeleton, muscles of the body, muscle contraction and types of joints.

Pectoral Girdle

The set of bones including the clavicle and scapula that attaches the upper limb to the axial skeleton.

Pelvic Girdle

The hip girdle formed by the hip bones (coxal bones) that attaches the lower limb to the axial skeleton.

Axial Skeleton

Consists of 80 bones forming the head and trunk of the body.

Appendicular Skeleton

Composed of 126 bones that make up the limbs and girdles.

Scapula

Also known as the shoulder blade, it is a flat triangular bone that helps anchor the upper limb.

Clavicle

The collarbone; a long S-shaped bone that links the shoulder to the sternum.

Humerus

The single bone of the upper arm, articulates with the scapula at the shoulder joint.

Femur

The longest and strongest bone in the body; the single bone of the thigh.

Tibia

The larger weight-bearing bone located on the medial side of the lower leg.

Fibula

The slender bone located on the lateral side of the lower leg, which does not bear weight.

Carpal Bones

Eight small bones that form the base of the hand, arranged in two rows.

Metacarpal Bones

Five long bones that form the palm of the hand.

Phalanges

14 bones that form the fingers and thumb.

Acetabulum

The large cup-shaped cavity on the lateral side of the hip bone that receives the head of the femur.

Glenohumeral Joint

The shoulder joint where the head of the humerus fits into the glenoid cavity of the scapula.

Sacroiliac Joint

The joint formed by the articulation between the sacrum and ilium of the pelvic girdle.

Tendons

Connective tissue that connects muscles to bones, facilitating movement of the skeleton.

Synovial Fluid

The lubricating fluid found in the joint cavity of synovial joints.

Motor Unit

The motor neuron and all of the muscle fibers it innervates, functional in muscle contraction.

Sliding Filament Model

The theory explaining how muscles contract by myosin heads pulling on actin filaments.

Twitch

A single contraction produced by one action potential in a muscle fiber.

Hinge Joint

A joint that allows movement primarily in one plane, seen in elbows and knees.

Ball-and-Socket Joint

A joint allowing for multi-axial movement, providing a wide range of motion, such as the shoulder and hip joints.

Bursae

Fluid-filled sacs that reduce friction between moving structures in the body.

Hypertrophy

An increase in muscle mass through the addition of structural proteins to muscle fibers.

Atrophy

A decrease in muscle size due to loss of structural proteins and muscle fibers.

Sarcopenia

Age-related muscle loss due to a decrease in muscle fibers and increase in non-contractile tissue.

Excitation-Contraction Coupling

The process by which an action potential triggers muscle contraction through Ca++ release.

Myofibrils

Cylindrical organelles within muscle fibers, composed of repeating units called sarcomeres.

Actin and Myosin

The contractile proteins in muscle fibers that interact to produce muscle contraction.

Neuromuscular Junction (NMJ)

The synapse where a motor neuron communicates with a muscle fiber to trigger contraction.

Calmodulin

A calcium-binding protein that activates myosin light chain kinase in smooth muscle contraction.

Single-unit Smooth Muscle

Smooth muscle fibers that contract as a single unit, often found in walls of visceral organs.

Multi-unit Smooth Muscle

Smooth muscle fibers that contract independently and are found in structures such as large blood vessels.

What bones are included in the appendicular skeleton?

The appendicular skeleton includes the bones of the limbs and girdles associated with the limbs, specifically the pectoral and pelvic girdles and the bones of the upper and lower limbs.

What is the role of the appendicular skeleton?

The appendicular skeleton facilitates movement and supports the attachments of muscles responsible for limb movement.

What are the bones of the upper limb?

The bones of the upper limb include the humerus, radius, ulna, carpals, metacarpals, and phalanges.

What are the bones of the lower limb?

The bones of the lower limb include the femur, tibia, fibula, patella, tarsals, metatarsals, and phalanges.

How many bones compose the pectoral girdle?

The pectoral girdle is composed of four bones: two clavicles and two scapulae.

What is the function of the pelvic girdle?

The pelvic girdle supports the weight of the upper body when sitting and standing, and it provides attachment points for the lower limbs.

What are the types of joints in the human body?

The types of joints include fibrous, cartilaginous, and synovial joints.

What is a fibrous joint?

Fibrous joints are joints where bones are connected by dense connective tissue, allowing little to no movement; examples include sutures in the skull.

What is a cartilaginous joint?

Cartilaginous joints are joints where bones are connected by cartilage, allowing limited movement; examples include intervertebral discs and the pubic symphysis.

What is a synovial joint?

Synovial joints are joints characterized by a fluid-filled joint cavity, allowing for free movement; examples include the knee, elbow, and shoulder joints.

What are the main features of synovial joints?

Synovial joints typically have a joint capsule, synovial membrane, synovial fluid, articular cartilage, and ligaments for stability.

What is a hinge joint?

A hinge joint is a type of synovial joint that allows movement primarily in one plane, such as the elbow and knee.

What is a ball-and-socket joint?

A ball-and-socket joint is a synovial joint that allows for multi-axial movement, providing a wide range of motion; examples include the shoulder and hip joints.

What is a pivot joint?

A pivot joint is a type of synovial joint that allows for rotational movement; an example is the joint between the first and second vertebrae in the neck.

What is a saddle joint?

A saddle joint is a synovial joint that allows for movement in two planes; an example is the joint at the base of the thumb (carpometacarpal joint).

What is a gliding joint?

A gliding joint is a synovial joint that allows limited sliding or gliding movements; examples include the joints between the carpal bones in the wrist.