Flashcards 3.3-4.3

What are the two main divisions of the skeleton?

Axial skeleton – Bones of head and trunk

Appendicular skeleton- Bones that support the limbs

What does the appendicular skeleton primarily support?

The limbs

How many bones are in the axial skeleton?

80 bones

What structures make up the axial skeleton?

Skull, vertebral column, and thoracic cage

What are the components of the skull?

8 cranial bones and 14 facial bones

What bones are associated with the skull?

Auditory ossicles and hyoid bone

What are the functions of the axial skeleton?

Support, protection, and muscle attachment

What movements does the axial skeleton assist with?

Head, neck, trunk movement and breathing

How many bones are in the skull?

22 bones

What is the function of cranial bones?

Enclose and protect the brain

What does the vertebral column protect?

The spinal cord

How many bones are in the vertebral column?

26 bones

What are the three parts of a vertebra?

Vertebral body, arch, and articular processes

What is the function of intervertebral discs?

Act as pads between vertebrae

What is the vertebral canal?

A passage enclosing the spinal cord

What are intervertebral foramina?

Openings for spinal nerve connections

What structures make up the thoracic cage?

Thoracic vertebrae, ribs, sternum, and cartilage

What is the function of the thoracic cage?

Protect organs and assist breathing

How many pairs of ribs are there?

12 pairs

What are true ribs and false ribs?

True ribs (1–7) attach to sternum; false ribs (8–12) do not

What are floating ribs?

Ribs 11–12 with no sternum attachment

What is the appendicular skeleton responsible for?

Movement and manipulation

What percentage of bones are appendicular?

About 60%

What bones form the pectoral girdle?

Clavicle and scapula

What is its function?

Connects arms to body

What bone is in the upper arm?

Humerus

What bones are in the forearm?

Radius and ulna

What connects radius and ulna?

Interosseous membrane

How many carpal bones are in the wrist?

8

What bones make up the pelvic girdle?

Ilium, ischium, pubis

What is the function of the pelvis?

Support weight and attach lower limbs

How does the female pelvis differ?

Lighter, wider, larger opening

What is the function of lower limbs?

Weight-bearing and movement

What is the longest bone in the body?

Femur

What bones are in the leg?

Tibia and fibula

What are joints also called?

Articulations

What happens to stability as joint mobility increases?

It decreases

What are the three movement classifications of joints?

Synarthrosis, amphiarthrosis, diarthrosis

What are structural joint types?

Bony, cartilaginous, fibrous

What are synovial joints and how are they stabilized?

Mobile joints stabilized by ligaments, tendons, cartilage, and bursae

What are planes and types of synovial joint movement?

Monaxial, biaxial, triaxial; gliding, angular, circumduction, rotation

What is flexion and extension?

Flexion decreases angle; extension increases angle

What is abduction and adduction?

Abduction moves away from midline; adduction moves toward

What is lateral and medial rotation?

Lateral rotates outward; medial rotates inward

What is supination and pronation?

Supination turns palm forward; pronation turns palm backward

What type of joint is the elbow and what bones are involved?

Hinge joint; humerus, radius, ulna

What type of joint is the knee and its function?

Complex hinge joint; transfers weight

What are menisci and their function?

Fibrocartilage pads that cushion and stabilize

What are major knee ligaments?

Cruciate and collateral ligaments stabilize the joint

What type of joints are shoulder and hip and what movements do they allow?

Ball-and-socket; allow movement in all directions

What is osteoarthritis?

Wear-and-tear joint disease common in older adults

What is rheumatoid arthritis and gout?

Autoimmune inflammation; uric acid crystal buildup

What happens to joints with aging?

Bone loss, weaker bones, higher fracture risk

What factors affect bone remodeling?

Age, hormones, stress, nutrients

What are the three muscle types?

Skeletal, cardiac, smooth

What is the main function of muscle tissue?

Contraction

What are properties of muscle cells?

Excitability, contractility, extensibility, elasticity

What do skeletal muscles do?

Move the body

What are functions of skeletal muscle?

Movement, posture, heat production, nutrient storage

What tissues are in skeletal muscle?

Muscle tissue, connective tissue, nerves, blood vessels

What are epimysium, perimysium, and endomysium?

Layers surrounding muscle, fascicles, and fibers

What do connective layers form at muscle ends?

Tendons or aponeuroses

What are skeletal muscle fibers?

Multinucleated, striated cells

Why are they striated?

Because of sarcomeres

What are myofilaments?

Actin (thin) and myosin (thick)

What is a sarcomere?

Functional unit of contraction

What happens in sliding filament theory?

Filaments slide to shorten muscle

What changes during contraction?

I and H bands shrink, Z lines move closer

What is the neuromuscular junction?

Synapse between neuron and muscle

What neurotransmitter is used and what does it do?

Acetylcholine; triggers Na⁺ influx and contraction

What is cardiac muscle?

Striated, involuntary muscle in heart with intercalated discs

What is smooth muscle and how is it controlled?

Non-striated muscle controlled hormonally and involuntarily

What does the muscular system consist of?

Skeletal muscles

What determines muscle performance?

Arrangement of fibers

What are fascicles and arrangement types?

Bundles of fibers; parallel, convergent, pennate, circular

What are parallel muscles and example?

Fibers parallel; biceps brachii

What are convergent muscles and example?

Fan-shaped; pectoralis

What are pennate muscles and their advantage?

Angled fibers; produce more force

What are circular muscles and example?

Sphincters; orbicularis oris

What is a lever and fulcrum in the body?

Bone is lever; joint is fulcrum

What are the three lever classes?

First, second, third (third most common)

What is a first-class lever and example?

Fulcrum between force and load; head movement

What is a second-class lever and example?

Load between force and fulcrum; standing on toes

What is a third-class lever and advantage?

Force between load and fulcrum; increases speed and distance

What is muscle origin and insertion?

Origin is fixed; insertion moves

What is an agonist and antagonist?

Agonist causes movement; antagonist opposes

What is a synergist and fixator?

Synergist assists; fixator stabilizes

How are muscles named?

By location, shape, action, origin, or structure