Anatomy & Physiology: Study Guide on Tissues, Skeletal, and Muscular Systems

Chapter 6: Cartilage and Bone Tissue

Types and Properties of Cartilage

Cartilage is a specialized connective tissue that provides support and flexibility to various parts of the body. There are three primary types of cartilage, each with distinct properties and functions.

• Hyaline Cartilage: Most abundant; provides support with some flexibility. Found in the nose, trachea, and at the ends of long bones.

• Elastic Cartilage: Contains more elastic fibers, allowing for greater flexibility. Found in the ear and epiglottis.

• Fibrocartilage: Highly compressible and strong; found in intervertebral discs and menisci of the knee.

Example: The meniscus in the knee is made of fibrocartilage, providing shock absorption during movement.

Bone Structure and Function

Bones are rigid organs that form the skeleton, providing structure, protection, and enabling movement. They also serve as sites for mineral storage and blood cell production.

• Major Regions of the Skeleton: The axial skeleton (skull, vertebral column, rib cage) and the appendicular skeleton (limbs and girdles).

• Bone Classes: Long, short, flat, and irregular bones, each with unique shapes and functions.

• Gross Anatomy: Typical long bones have a diaphysis (shaft), epiphyses (ends), and metaphyses (growth regions).

• Bone Markings: Include projections, depressions, and openings for muscle attachment and passage of nerves/vessels.

Example: The femur is a long bone with a prominent head (epiphysis) that articulates with the hip.

Bone Tissue Composition and Types

Bones are composed of organic (collagen fibers) and inorganic (hydroxyapatite crystals) components, providing both flexibility and strength.

• Compact Bone: Dense outer layer providing strength.

• Spongy Bone: Porous inner layer containing red marrow for blood cell production.

Table: Comparison of Compact and Spongy Bone

Feature	Compact Bone	Spongy Bone
Location	Outer layer of bones	Inner layer, ends of long bones
Structure	Osteons (Haversian systems)	Trabeculae
Function	Strength, support	Lightweight, houses marrow

Bone Development and Remodeling

Bone formation occurs through two processes: intramembranous ossification (flat bones) and endochondral ossification (long bones). Bone remodeling is a continuous process involving osteoblasts (bone formation), osteoclasts (bone resorption), and osteocytes (maintenance).

• Hormonal Regulation: Parathyroid hormone (PTH) and calcitonin regulate blood calcium levels and bone remodeling.

• Physical Stress: Weight-bearing exercise stimulates bone growth and strength.

Example: Osteoporosis is a disorder characterized by decreased bone mass and increased fracture risk.

Chapter 9: Joints and Articulations

Classification and Structure of Joints

Joints, or articulations, are connections between bones that allow for movement and flexibility. They are classified by structure and function.

• Structural Classification: Fibrous, cartilaginous, and synovial joints.

• Functional Classification: Synarthroses (immovable), amphiarthroses (slightly movable), diarthroses (freely movable).

Example: The knee is a synovial joint, allowing for flexion and extension.

Fibrous Joints

Fibrous joints are connected by dense connective tissue and allow little to no movement. Types include sutures (skull), syndesmoses (between tibia and fibula), and gomphoses (teeth in sockets).

Cartilaginous and Synovial Joints

• Cartilaginous Joints: Bones united by cartilage (e.g., intervertebral discs).

• Synovial Joints: Most movable type; characterized by a joint cavity filled with synovial fluid.

Example: The shoulder is a ball-and-socket synovial joint, allowing for a wide range of motion.

Joint Movements and Disorders

• Types of Movement: Flexion, extension, abduction, adduction, rotation, and circumduction.

• Common Disorders: Arthritis (inflammation), dislocations, and sprains.

Example: Osteoarthritis is a degenerative joint disease common in older adults.

Chapter 10: Muscle Tissue and Physiology

Types and Functions of Muscle Tissue

Muscle tissue is specialized for contraction and movement. There are three main types:

• Skeletal Muscle: Voluntary, striated, attached to bones for movement.

• Cardiac Muscle: Involuntary, striated, found only in the heart.

• Smooth Muscle: Involuntary, non-striated, found in walls of hollow organs.

Table: Comparison of Muscle Types

Feature	Skeletal	Cardiac	Smooth
Control	Voluntary	Involuntary	Involuntary
Striations	Yes	Yes	No
Location	Bones	Heart	Viscera

Structure and Function of Skeletal Muscle

• Muscle Fiber Anatomy: Each muscle fiber contains myofibrils composed of actin and myosin filaments.

• Sliding Filament Model: Muscle contraction occurs as actin and myosin filaments slide past each other.

• Neuromuscular Junction: Site where a motor neuron stimulates a muscle fiber to contract.

Example: Lifting a weight involves voluntary contraction of skeletal muscle fibers.

Muscle Contraction and Energy

• Excitation-Contraction Coupling: Sequence of events from nerve signal to muscle contraction.

• ATP Regeneration: Muscles use creatine phosphate, glycolysis, and aerobic respiration to regenerate ATP.

• Isotonic vs. Isometric Contractions: Isotonic involves movement; isometric involves tension without movement.

Equation:

$\text{ATP} \rightarrow \text{ADP} + \text{P}_i + \text{energy}$

Muscle Fatigue and Disorders

• Muscle Fatigue: Decline in ability to generate force, often due to depletion of ATP or accumulation of lactic acid.

• Disorders: Muscular dystrophy, myasthenia gravis, and cramps.

Chapters 7, 8, 11: Lab Take-Aways

Skull, Cranial, and Facial Bones

• Identification: Recognize and name the major bones and markings of the skull.

• Function: Protects the brain and supports facial structure.

Axial and Appendicular Skeleton

• Pectoral Girdle: Connects upper limbs to the trunk; includes clavicle and scapula.

• Pelvic Girdle: Supports lower limbs; differences exist between male and female pelvises for childbirth.

• Upper and Lower Limbs: Identify major bones and their markings (e.g., humerus, femur, tibia).

Example: The os coxae forms the pelvic girdle, providing strength and support for the body’s weight.

Additional info:

• Some content inferred for completeness, such as specific examples of bone and muscle disorders, and the inclusion of basic equations for muscle contraction energy.