EAM 3 PHYL 141

Structural Classification of Joints

Fibrous joints, cartilaginous joints, and synovial joints

Functional Classification of Joints

Synarthrosis, amphiarthrosis, and diarthrosis

Synarthrosis

Immovable joint

Amphiarthrosis

Slightly movable joint

Diarthrosis

Freely movable joint

Fibrous Joint

Bones are held together by dense irregular connective tissue and lack a joint cavity

Types of Fibrous Joints

Sutures, syndesmoses, and gomphoses

Suture

Immovable fibrous joint found between skull bones

Synostosis

Fusion of two bones into one bone

Syndesmosis

Fibrous joint connected by ligaments or interosseous membrane

Gomphosis

Joint between a tooth and its socket

Cartilaginous Joint

Bones connected by cartilage and lack a synovial cavity

Synchondrosis

Cartilaginous joint united by hyaline cartilage

Symphysis

Cartilaginous joint united by fibrocartilage

Synovial Joint

Joint with a fluid-filled synovial cavity allowing free movement

Outer Layer of Synovial Capsule

Fibrous capsule

Inner Layer of Synovial Capsule

Synovial membrane

Synovial Fluid

Lubricates joints and nourishes cartilage

Bursa

Fluid-filled sac that reduces friction between structures

Bursitis

Inflammation of a bursa

Gliding Movement

Flat surfaces slide past one another

Flexion

Decrease in the angle between bones

Extension

Increase in the angle between bones

Hyperextension

Extension beyond the anatomical position

Dorsiflexion

Movement of the foot upward toward the shin

Plantar Flexion

Movement of the foot downward

Supination

Turning the forearm so the palm faces upward

Pronation

Turning the forearm so the palm faces downward

Opposition

Movement of the thumb across the palm

Plane Joint

Flat articulating surfaces allowing gliding movements

Hinge Joint

Convex surface fits into concave surface allowing movement in one plane

Pivot Joint

Rounded surface rotates within a ring formed by bone and ligament

Condyloid Joint

Oval convex surface fits into oval depression allowing movement in two axes

Saddle Joint

Modified condyloid joint allowing movement in multiple axes

Ball-and-Socket Joint

Spherical head fits into cup-like socket allowing greatest range of motion

Shoulder Joint Bones

Scapula and humerus

Shoulder Joint Type

Ball-and-socket synovial joint

Knee Joint Bones

Femur, tibia, and patella

Knee Joint Type

Modified hinge synovial joint

Arthroplasty

Surgical replacement of a joint

Rheumatoid Arthritis

Autoimmune disease causing inflammation and destruction of joints

Functions of Muscular Tissue

Movement, posture, movement of substances, and heat production

Skeletal Muscle Control

Voluntary

Cardiac Muscle Control

Involuntary

Smooth Muscle Control

Involuntary

Skeletal Muscle Appearance

Striated and multinucleated

Cardiac Muscle Appearance

Striated with one central nucleus

Smooth Muscle Appearance

Nonstriated with one central nucleus

Epimysium

Connective tissue surrounding an entire muscle

Perimysium

Connective tissue surrounding a fascicle

Endomysium

Connective tissue surrounding a muscle fiber

Muscular Atrophy

Decrease in muscle size due to inactivity or disease

Sarcolemma

Plasma membrane of a muscle fiber

Sarcoplasm

Cytoplasm of a muscle fiber

Myoglobin

Oxygen-binding protein in muscle cells

Sarcoplasmic Reticulum

Stores and releases calcium ions

Terminal Cisterns

Enlarged sacs of the sarcoplasmic reticulum

Triad

One T-tubule and two terminal cisterns

Myofibril

Contractile organelle within muscle fibers

Sarcomere

Functional unit of muscle contraction

Z Disc

Boundary of a sarcomere

A Band

Region containing thick filaments

I Band

Region containing thin filaments only

H Zone

Region containing thick filaments only

M Line

Center of the sarcomere

Contractile Proteins

Actin and myosin

Regulatory Proteins

Troponin and tropomyosin

Structural Proteins

Titin and associated support proteins

Actin

Thin filament protein containing myosin-binding sites

Myosin

Thick filament protein with ATPase activity

Role of Troponin

Binds calcium and moves tropomyosin away from binding sites

Role of Tropomyosin

Blocks myosin-binding sites on actin during relaxation

Cross-Bridge

Connection formed between myosin head and actin

Power Stroke

Movement of myosin head pulling actin toward the center of the sarcomere

Role of ATP in Contraction

Energizes myosin and allows detachment from actin

Neuromuscular Junction

Junction between a motor neuron and a skeletal muscle fiber

Presynaptic Membrane

Membrane of the neuron terminal

Postsynaptic Membrane

Motor end plate of the muscle fiber

Synaptic Cleft

Gap between neuron and muscle fiber

Acetylcholine

Neurotransmitter released at the neuromuscular junction

Acetylcholinesterase

Enzyme that breaks down acetylcholine

Motor End Plate Potential

Electrical change produced in the muscle membrane

Excitation-Contraction Coupling

Process linking muscle action potential to contraction

Stored ATP

Immediate source of energy for muscle contraction

Creatine Phosphate

Rapidly regenerates ATP during short bursts of activity

Anaerobic Glycolysis

Produces ATP without oxygen and generates lactic acid

Aerobic Respiration

Produces large amounts of ATP using oxygen

Motor Unit

One motor neuron and all the muscle fibers it controls

All-or-None Principle

All muscle fibers in a motor unit contract together when stimulated

Muscle Twitch

Response of a muscle fiber to a single stimulus

Latent Period

Time between stimulus and contraction

Contraction Period

Time when muscle develops tension

Relaxation Period

Time when muscle returns to resting state

Isotonic Contraction

Muscle changes length while producing movement

Concentric Contraction

Muscle shortens while generating force

Eccentric Contraction

Muscle lengthens while generating force

Isometric Contraction

Muscle develops tension without changing length

Origin

Attachment of a muscle to the less movable bone

Insertion

Attachment of a muscle to the more movable bone

Bones in Movement

Act as levers