Joints

Chapter 7

Bio160

Types of Joints

Fibrous – Sutures between skull bones, between teeth and jaw and between radius and ulna and tibia and fibula

Cartilaginous – Epiphyseal plate, costal cartilage, between vertebrae and pubic symphysis

Types of Synovial Joints• Gliding – intercarpal and intertarsal,

sternoclavicular, acromioclavicular, sternocostal, and vertebrocostal

• Hinge – knee, elbow, ankle and interphalangeal

• Pivot – atlanto-axial, radioulnar

• Condyloid – wrist and metacarpophalangeal (2-5)

Types of Synovial Joints

• Saddle – carpometacarpal in thumb

• Ball and Socket – shoulder and hip

Types of Movements at Synovial Joints

• Flexion and Extension

• Abduction and Adduction

• Inversion and Eversion

• Elevation and Depression

• Supination and Pronation

• Dorsiflexion and Plantar Flexion

• Rotation

Muscle Tissue

Chapter8

Bio160

Connective Tissue Components

• Entire muscle is wrapped in fibrous connective tissue which is continuous with tendons that insert skeletal muscle into bone

• This outer connective tissue of muscle can also be called deep fascia (sheet of fibrous connective tissue) as compared to superficial fascia also known as subcutaneous tissue

Connective Tissue Components• Connective tissue holds muscle together as

well as serving to transmit blood vessels and nerves to inner muscle cells

Epimysium - outside of entire muscle

Perimysium - divides muscle cells into fascicles (bundles)

Endomysium - covers individual muscle cells

• Connective tissue layers of skeletal muscle

Histology

• Large → Small: fascicle → fiber → fibril → filament

Sarco = fleshy

• Muscle consists of elongated cells called muscle fibers

• Sarcolemma - cell membrane

Histology

• Transverse (T) tubule - tubular invagination of sarcolemma that surrounds each myofibril

• Sarcoplasm – cytoplasm

• Sarcoplasmic reticulum (SR) - smooth endoplasmic reticulum that stores Ca2+, has enlarged portions called cisternae that surround the transverse tubules

Histology

• Myofibrils – cross section of muscle cell consists of small cylinders called myofibrils which may number several 100 to several 1000/cell (exercise increases myofibril production; lack of exercise decreases myofibrils (atrophy))

Each myofibril consists of myofilaments (protein)

Histology

– thick myofilaments = myosin

– thin myofilaments = actin, troponin, tropomyosin

Histology

– thick myofilaments = myosin

– thin myofilaments = actin, troponin, tropomyosin

Each myofibril is surrounded by SR

Histology

• Sarcomere - myofilaments don't extend entire length of muscle fiber; they are stacked into compartments called sarcomeres

Sarcomeres are the functional unit of a skeletal muscle (contractile unit)

Myofilament arrangement in sarcomeres results in alternating pattern of light and dark staining bands

Histology (6)

Parts of sarcomere

– A band - myosin + overlapping actin, dark staining band

– I band - only actin, troponin, tropomyosin (2 I bands / sarcomere), light staining band

– Z disc – through center of I band