A&P Unit 3: Musculoskeletal System Review

Bone Function

supports structure, protection of vital organs, movement, mineral storage, and blood cell production

Long Bones example

includes femur, humerus, and tibia.

Short Bones example

includes carpals and tarsals.

Flat Bones Example

includes skull, ribs, and sternum.

Irregular bones example

includes vertebrae and pelvis.

sesamoid Bones example

includes patella and some in hands and feet.

Long Bone Charcteristics

Elongated shape, composed of diaphysis (shaft) and epiphysis (two ends)

Short Bone characteristics

Cube shaped, equal length to width

Flat Bones characteristics

Provide protection and broad surfaces for muscle attachment

Irregular Bone characteristics

Complex bones that dont fit other catergories

Sesamoid Bone characteristics

Small round bones embedded in tendons to reduce friction and chnage angle of force

Long Bone Function

designed for movement and leverage

Short Bone function

Provide stability and support

Long Bone composition

More compact bone in diaphysis and more spongy bone in epiphysis

Short Bone composition

Mostly spongy bone

Transverse fracture

Runs perpendicular to the bone, caused by direct perpendicular force

Oblique Fracture

Fracture runs on an angle to the bone, caused by force applied by an angle

Spiral Facture

Spirals around the bone caused by twisting or rotational force

Comminuted fracture

Bone breaks into three or more fragments caused by crushing or severe trauma

Avulsion Fracture

A piece of bone is pulled away caused by sudden muscle contraction or ligament pull

Impacted Fracture

One bone fragment is driven into another by a compression force

Hairline Fracture

Partial fracture that doesnt break completely through the bone. Caused by minor trauma

Greenstick

Incomplete fracture where bone bends and partially breaks, most common in children

Simple Fracture

Bone is broken but skin remains intact

Open Fracture

The bone is broken and pierces through the skin.

Displaced Fracture

The broken bone fragments are separated and out of alignment

Non-Displaced Fracture

The bone remains in place in proper alignment

Bone recovery; Hematoma Formation

Stage 1: Blot clot forms, Inflammatory response begins, Swelling and pain occurs

Bone recovery; Soft Callus Formation

Stage 2 of Bone Recovery: Osteoblasts begin to produce new bone matrix, Cartilage and fibrous tissue form around fracture site providing temporary stability

Bone Recovery; Hard Callus formation

Stage 3 of Bone Recovery: Osteoblasts continue to deposit calcium and minerals, cartilage is replaced by woven bone, fracture becomes more stable

Bone recovery; Remodeling Phase

Osteoclasts remove excess bone and remodel the fracture site, woven bone is replaced by mature compact and spongy bone, the bone returns to original shape and strength

Osteoblasts

Build new bone by depositing bone matrix; active in steps 2-4 of Bone Repair

Osteoclasts

Break down and remove access bone; active in step 4 of bone recovery

What is osteopenia

Precursor to osteoporosis, bone density is lowered but not extreme. Caused by inadequate calcium intake leading to decreased bone mineralization.

Effects of Osteoporosis on bone matrix

causes deterioration of bone matrix making bone less dense/more fragile

Role of calcium in bone

Provides hardness and strength for bones

What is Compact Bone

Dense hard bone tissue that forms the outer later, provide strength and support

What is Spongy bone

Porous bone tissue inside the bone; contains bone marrow and lighter than compact bone

What is Periosteum 

A tough fibrous membrane covering the outer surface of bone; contains blood vessels and nerves; serves as attachment point for tendons and ligaments

Haversian Canals

Small channels running through compact bone containing blood vessels and nerves allowing nutrient delivery and waste removal form osteocytes

Bone marrow location

Found in the medullary cavity; the hollow center of long bones, as well as in the spaces of spongy bone

Bone Marrow Function

Produces blood cells (red, white, platelets)

Bone Marrow Types

Red marrow (hematopoietic) and Yellow Marrow (adipose tissue)

Skeletal Muscles

Muscles that require voluntary movement

Cardiac Muscles

Heart muscles; subconscious contractions

Smooth Musclles

Unvoluntary muscle contractions that support organs and blood vessels

Function of muscle tissues

Movement of body, maintenance of posture, Heat production, protection of internal organs, movement of substances  throughout the body

Tendon

Connective tissue that attaches muscle to bone

Epimysium

Outermost connective tissue layer surrounding the entire muscle

Fascicle

Bundle of muscle fibers grouped together

Perimysium

Connective tissue surrounding each fascicle

Muscle Fiber

Individual Muscle cell

Endomysium

Connective tissue surrounding each muscle fiber.

Myofibrils

Contractile structures within muscle fibres

Myofilaments

Protein filaments that make up myofibrils (actin and myosin)

Function of Epimysium

Provides protection and support for the entire muscle; allows for movement

Function of Perimysium

Groups muscle fibers into functional units, contains blood vessels and nerves

Function of Endomysium

Surrounds individual muscle fibers; contains capillaries for nutrient delivery

Muscle strains

Overstretching or tearing of muscle fibers causing pain

Muscle Cramps

Involuntary muscle contraction causing pain

Tendinitis

Inflammation of tendons causing pain and reduced movement

Aerobic Respiration

High efficient ATP production requiring O2 and produces CO2 - Long term strength

Anaerobic Fermentation

Low efficient ATP production that does not require O2 and produces Lactic Acid - Bust Strength

Causes of muscle fatigue

Depletion of ATP and phosphocreatine stores, accumulation of lactic acid and hydrogen ions, depletion of calcium, accumulation of metabolic byproducts.

Role of Creatine Phosphate

Serves as rapid ATP buffer system providing immediate energy for muscle contraction, only good for very short bursts

Agonist

The contracting muscle

Antagonist

Opposing the contacting muscle (must relax for movement)

Synergist

The assisting muscles to the contrcation

Flexion

Decreasing the angle at a joint; bending

Extension

Increasing the angle at a joint; straightening

Abduction

Moving a limb away from the midline

Adduction

Moving a limb closer to the midline

Rotation

Turning a bone around its axis

Circumduction

Moving a limb in a circular motion

Pronation

Rotating forearm so palm faces down

Supination

Rotating the forearm so hand faces upward

Sliding filament theory

The contraction of muscles

Action Potential

The neurons signal for a muscle: Step one of Sliding Filament Theory (SFT)

Acetylcholine

Binds to receptors on the muscle fiber membrane causing depolarization and action potential in muscle fiber: step 2 of Sliding Filament Theory (SFT)

T-tubule

Trigger for calcium release sparked by action potential: Step 3 of SFT

Calcium role in SFT

Binds to troponin which moves the tropomyosin away from the myosin binding sites on actin: Step 4 of SFT

Myosin Heads

Things that attach to the actin forming a crossbridge for contraction: Step 5 of SFT

Powerstroke

Myosin heads pull the actin filaments towards the center of the sarcomere: Step 6 of SFT

What is released in a powerstroke

ADP and phosphate: Step 7 of SFT

What unbinds the myosin head from actin

The bonding of new ATP to the myosin head: Step 8 of SFT

What gives Myosin the energy to bind to Actin

The hydrolyzation of ATP creates ADP and Phosphate, providing energy to the myosin head: Step 9 of SFT

What happens when a contraction stops (SFT)

Calcium is pumped back into sarcoplasmic reticulum, tropomyosin covers the binding sites

Sarcoplasmic Reticulum

Responsible for storing releasing and absorbing calcium.