Mod 6
SKELETAL SYSTEM
Module 6: Skeletal Chapter 13
Points to Ponder
What are the 5 functions of the skeletal system?
What is compact bone? Spongy bone?
How are bones classified?
What are the parts of a long bone?
What are the differences between red and yellow marrow?
Functions of the Skeletal System
Support: Provides structural support for the body, primarily through the legs and pelvic girdle.
Protection: Protects soft body parts:
Skull protects the brain.
Ribcage protects the heart and lungs.
Vertebrae protect the spinal cord.
Produces Blood Cells: Blood cells are produced by stem cells located in red bone marrow.
Stores Minerals and Fat: Stores vital minerals such as calcium and phosphate, as well as fat.
Movement: Facilitates movement by providing attachment points for muscles.
Types of Bone
Compact Bone:
Composed of osteons, which possess a central canal containing blood vessels.
Contains living bone cells, termed osteocytes.
Features chambers known as lacunae.
Yellow marrow is located in the medullary cavity.
Primarily found in the diaphysis (middle portion) of long bones.
Provides protection, support, and resistance to external stresses.
Spongy Bone:
Comprised of plates of bone known as trabeculae, filled with red bone marrow.
Displays a disorganized and irregular arrangement of osteocytes.
Lighter in weight compared to compact bone.
Red bone marrow is found within the spaces of spongy bone.
Located primarily in the epiphysis (ends) of long bones, and in areas of growth plates.
Classification of Bones
Long Bones: Example: Femur
Short Bones: Example: Carpals
Flat Bones: Example: Parietal Bone
Irregular Bones: Example: Vertebrae
Sesamoid Bones: Example: Patella
Bone Cells
Osteoblasts: Bone-forming cells that are responsible for new bone development.
Osteocytes: Mature bone cells derived from osteoblasts that help maintain bone structure.
Osteoclasts: Bone-absorbing cells that are responsible for breaking down bone tissue.
Anatomy of a Long Bone
Diaphysis:
The shaft of the bone composed of compact bone and filled with yellow marrow.
Epiphysis:
The ends of the bone primarily made up of spongy bone.
Articular Cartilage:
Hyaline cartilage located at the ends of long bones that reduces friction in joints.
Yellow Bone Marrow:
Functions primarily in fat storage and is found in the medullary cavity.
Red Bone Marrow:
Responsible for blood cell production, found in spongy bone and some flat bones.
Periosteum:
A fibrous connective tissue layer that covers the outer surface of the bone, containing nerves and blood vessels.
Ligaments:
Fibrous connective tissue that connects bones at joints.
Osteoporosis
Definition: A condition characterized by decreased bone mass, leading to fragile bones.
Pathophysiology: Occurs when bone reabsorption exceeds bone formation, typically starting around age 40.
Risk Factors:
Gender: Females are at higher risk.
Ethnicity: Higher prevalence in White or Asian individuals.
Body type: Thin individuals are more susceptible.
Family history: Genetic predisposition.
Age: Early menopause can increase risk.
Lifestyle: Smoking, low calcium intake, excessive caffeine or alcohol consumption, and a sedentary lifestyle contribute.
Complications: Increased risk of fractures and other related complications.
Treatment: Management can include drugs, hormonal therapies, and lifestyle modifications.
MUSCULAR SYSTEM
Module 6: Chapter 14
Points to Ponder
What are the 3 types of muscle tissue?
What are the functions of the muscular system?
What terms are used to describe muscle movements?
How do skeletal muscle cells acquire ATP for contraction?
What are some serious muscle diseases?
How do the skeletal and muscular systems help maintain homeostasis?
Types of Muscle Tissue
Skeletal Muscle:
Appearance: Long, parallel cells (fibers) that are multinucleated and striated.
Location: Attached to bones or skin.
Control: Voluntary control via the somatic nervous system.
Cardiac Muscle:
Appearance: Branched cells connected by intercalated discs containing desmosomes and gap junctions.
Location: Found exclusively in the heart.
Control: Involuntary control via the autonomic nervous system.
Smooth Muscle:
Appearance: Small cells with tapered ends that can function individually or as a multi-unit.
Location: Found in blood vessels, the digestive tract, bronchial tubes, and various organs.
Control: Involuntary control via the autonomic nervous system.
Functions of the Muscular System
Movement: Generates body movements through muscle contractions.
Stabilization: Helps maintain body position and posture.
Internal Movement: Coordinates the movement of internal organs and systems.
Blood Flow Regulation: Influences blood circulation within the body.
Heat Production: Generates heat through muscle activity to maintain body temperature.
Muscle Structure Terminology
Sarcoplasm: Cytoplasm of a muscle cell.
Sarcolemma: Plasma membrane of a muscle cell.
Sarcoplasmic Reticulum: The smooth endoplasmic reticulum in muscle cells, which serves to store calcium ions.
Muscular Movement
Attachments:
Tendons: Connective tissue connecting muscle to bone.
Origin: The attachment point of a muscle on a stationary bone.
Insertion: The attachment point of a muscle on the moving bone.
Action:
Antagonistic Muscles: Muscles that function in opposition to each other.
Synergistic Muscles: Groups of muscles that work together for a common action.
Agonist: The primary muscle responsible for a specific movement during contraction.
Muscle Energy Sources
Muscles utilize glycogen, triglycerides, and creatine phosphate (stored in sarcoplasm) to generate ATP.
Upon depletion of these sources, glucose and fatty acids may enter muscle cells.
ATP Sources
Creatine Phosphate Pathway: The fastest method for muscle ATP acquisition but lasts for only seconds, replenishes during rest.
Fermentation: An anaerobic process that produces ATP but leads to lactate accumulation.
Cellular Respiration: An aerobic mechanism that, while not immediate, provides the best long-term ATP supply.
Muscular Diseases
Fibromyalgia: A condition characterized by chronic muscle pain with an unclear etiology.
Myalgia: General muscle pain often resulting from infections or overexertion.
Muscular Dystrophy: A collection of genetic disorders causing progressive muscle degeneration and weakness.
Myasthenia Gravis: An autoimmune condition that targets acetylcholine receptors, resulting in muscle weakness, particularly in facial and neck muscles.
Amyotrophic Lateral Sclerosis (ALS): Also known as Lou Gehrig’s disease, marked by the degeneration of motor neurons that control voluntary muscle movements.
Homeostasis: Interaction between Skeletal and Muscular Systems
The skeletal and muscular systems facilitate movement, responding to stimuli and ensuring digestion, respiratory activities, and blood return to the heart.
They offer protection to internal organs and minerals stored in bones contribute to muscle contraction and neurological function.
Blood cells are generated within bone marrow, while muscle activity helps regulate body temperature.
Summary
The skeletal system is responsible for structural support, movement, protection of organs, mineral storage, and blood cell production.
Bone types include compact and spongy influenced by their structural functions.
Bones are classified into five categories: long, short, flat, irregular, and sesamoid.
The muscular system consists of skeletal, smooth, and cardiac tissues with various functions including motion, posture stabilization, regulation, and heat generation.
Muscle cells, each called a fiber, require ATP acquired through creatine phosphate, glycolysis, or oxidative phosphorylation.
Objectives
Examine the structure and function of skeletal and muscular systems.
Identify various bone types and structures.
Explain the skeletal system's functions.
Distinguish between different types of bone.
Describe osteoporosis and its effects.
Clarify the roles of ligaments and tendons.
Investigate how muscles obtain ATP.
Summarize the interconnection between bones and muscles for movement.
Define muscle-specific terminology.
Examine muscular diseases affecting function.