Skeletal System Recording (W2025)

Class Overview

• Completed the second week of class; expect a consistent routine moving forward, focusing nightly on different body systems.

• Clinical questions regarding body systems will continue, starting with the Skeletal System.

Personal Story About Skeletal System

• Shared an email from the instructor's daughter regarding a dog's X-ray indicating hip issues.

• The dog's X-ray illustrated differences in hip alignment, suggesting possible trauma.

• The dog requires surgery, involving the removal of the femur head, which will be replaced by muscle and ligament stability.

Integumentary System Clinical Question

• Medical and transdermal patches can replace oral medication for:

  • Unconscious patients.

  • Hormone replacement therapy.

  • Heart disease treatment.

  • Pain management.

  • Motion sickness.

  • Smoking cessation (e.g., nicotine patches).

• Placement of Patches: Generally applied to non-obtrusive areas like the upper arm, avoiding clothing contact.

• Mechanism: Medications through the epidermis into the dermis, absorbed by blood vessels.

Pros of Transdermal Patches

• Continuous medication release, avoiding peaks and troughs of medication levels.

• Reduces the need to remember doses.

• Easy removal of patches when discontinuing medication.

• Low doses typically have minimal side effects.

• Minimizes GI issues associated with oral medications.

• Reduced overdose risk; especially beneficial for comatose patients.

Cons of Transdermal Patches

• Possible skin irritation at the application site.

• Risk of developing skin sensitivity over time.

• Limited effectiveness with many drugs.

Functions of the Skeletal System

• Acts as a framework, akin to rebar in construction, holding the body together.

• Provides attachment points for muscles, enabling movement.

• Protects vital organs (brain, heart, lungs) encased within bony structures (cranium, rib cage, vertebral column).

• Serves as storage for minerals, particularly calcium, crucial for bodily functions.

• Hematopoiesis: Blood cell production occurs in the bone marrow.

Types of Bones

• Total Bones in Adults: 206

• **Types:

  • Flat Bones:** e.g., ribs, cranium (thin/slightly curved).

  • Long Bones: e.g., femur (typical bone shape).

  • Short Bones: e.g., carpals and tarsals (cube-like).

  • Irregular Bones: e.g., vertebrae (complex shapes).

  • Sesamoid Bones: e.g., patella (bones embedded within tendons).

Bone Structure and Types of Bone Tissue

Bone Composition

• Osseous Tissue: Part of the skeletal system; encompasses two types:

  • Compact Bone: Dense and forms outer layer; contains osteons, central canals, and blood vessels.

  • Spongy Bone: Lighter, porous structure; contains trabeculae; found inside flat bones and at ends of long bones.

Bone Formation Process

• Endochondral Ossification: Stage of bone formation beginning with a cartilage model which is then replaced by bone tissue.

• Osteoblasts produce collagen which, combined with minerals from the blood, hardens into bone.

• Mature Bone Cells: After mineralization, osteoblasts trapped within lacunae become osteocytes.

Joint Types

Joint Classification

• Fibrous Joints: (Synarthrosis) Immovable joints like those in the skull.

• Cartilaginous Joints: (Amphiarthrosis) Slightly movable joints like intervertebral discs.

• Synovial Joints: (Diarthrosis) Freely movable joints including:

  • Ball and Socket: e.g., hip, shoulder (high mobility, lower stability).

  • Hinge Joints: e.g., elbow, knee (move in one direction).

  • Pivot Joints: e.g., joints allowing rotation (radius and ulna).

  • Gliding Joints: e.g., carpals and tarsals (allow sliding movement).

  • Saddle Joints: e.g., thumb joints (allow two-directional movement).

  • Condyloid Joints: e.g., fingers (allow movement in two planes).

Age-Related Bone Changes

• Calcium availability decreases with age, leading to fragile bones.

• Intervertebral discs thin, possibly resulting in reduced height over time.

• Arthritis may develop due to thinning cartilage between bones.

Miscellaneous Notes

• X-Rays and Bone Health: Shared personal pictures of X-rays showing a dog's injury and surgical intervention showcasing the use of pins for stabilization.