13.1 Musculoskeletal Part 1 Flashcards
Musculoskeletal System
- Provides form, stability, and movement to the body
- Chief component of connective tissue such as tendons and ligaments are collagen and elastic fibers
Formation of Bone
- In embryo’s the skeleton is primary made of hyaline cartilage
- During development hyaline cartilage gets replaced into bone
- Epiphyseal plates in bones allow bones to grow longer
(This is where new cartilage is formed and old cartilage is ossified)
DEFINITION OF OSSIFY
- Cartilage is broken down and replaced with bone by osteoblasts.
Ossification (Bone Growth)
- Bones are always being remodeled throughout life based on 2 factors. These include..
1. Pull of gravity (the more stress on a bone, the more dense it gets)
2. Blood calcium levels
Appositional Growth - Bones growing in width.
General Facts of Bones
- Bone starts growing in the middle of the hyaline cartilage
- Epiphyseal plates are known as growth plates (because they help a bone grow)
- Bone growth - Hyaline cartilage continues to grow at the end of bones in-turn growing bone underneath.
- Bone remodeling - This is when bones reshape as you age. Bone tissue gets broken down by osteoclasts and built back up by osteoblasts. Some bone gets shaved off where its not needed and built up where it is needed.
Bone Cells
Osteocytes - Mature bone cells
Osteoblasts - Bone building cells
Osteoclasts - Giant bone destroying cells
Bone Fractures
- Break in the bone
Closed (simple) fractures - Break that does not penetrate skin
Open (compound) fractures - Broken bone penetrates the skin
Repair of Bone Fractures
1st - Hematoma is formed (blood filled swelling)
2nd - The bone break is splinted by a fibrocartilage callus (framework to help bone heal)
3rd - The cartilage is replaced by a bony callus
4th - The bony callus is replaced by a permanent “patch” of bone
In-detail Bone Cells
Osteoblasts - Function in bone formation
Osteocytes - Function as bone maintenance (located in lacunae)
Osteoblasts - Function in destroying, resorbing, and remodeling bone (located in Howship lacunae)
Osteogenesis - Process of bone formation
Ossification - Formation of bone matrix and deposition of minerals
- BONES ARE ALWAYS IN A CONSTANT STATE OF TURNOVER (they are formed and destroyed constantly)
BONE REGULATION FACTORS (what constitutes how much they breakdown or how much they are formed)
- Stress/Weight Bearing (The more weight you bear on your bones, the denser it gets)
- Vitamin D (The more vitamin D you have the more calcium is absorbed)
- Parathyroid hormone and calcitonin
- Blood supply
- Calcium
Bone Healing
Stage 1 - Hematoma Formation (1-2 days after fracture)
Stage 2 - Fibrocartilaginous Callus Formation (Fibroblasts and Osteoblasts migrate to Fracture Site)
Stage 3 - Bony Callus Formation (Ossification Starts During 3-4 Weeks)
Stage 4 - Remodeling (Osteoclasts Remove Necrotic Bone)
Joints (Articulations)
- Junction of 2 or more bones
Synarthrosis - Immovable joints (ex. between bones of the skull)
Amphiarthrosis - Allow limited movement (ex. symphysis pubis and between vertebrae of spine)
Diarthrosis - Freely moveable joints
(Ball and Socket Joint - Shoulder and Hips)
(Hinge Joints - Knees and Fingers)
(Saddle Joints - Base of Thumb)
(Pivot Joints - Neck)
(Gliding Joints - Between Carpal and Tarsal Bones)
(Condyloid Joints - Wrists and Temporomandibular Joints)
Joint Structures
- Joint Capsule - The area of tough fibrous tissue surrounding a synovial joint sealing it
- Ligaments - Connects bone to bone
- Tendons - Connects bone to muscle
- Bursa Sac - Fluid filled sacs that cushion joints
Muscles
- Attached to bone and other structures by TENDONS
- Fascia (encases muscle in fibrous tissue)
- Contraction of muscle is powered by ATP. They react to electrical impulses
- During strenuous muscle activity, anaerobic energy (does not require oxygen) is used. This is when glucose metabolized from glycogen provides additional needed energy.
- Using your muscles results in hypertrophy and disuse results in atrophy
Muscle Tone (Tonus)
- Amount of tension generated by muscles in a contracted state.
- Muscle tone is monitored by muscle spindles (sense organs)
- Muscle tone is little when sleeping and high when anxious
Flaccid - Limp, no tension muscle tone
Spastic - Greater than normal tone
Atonic - Denervated (no nerves) muscle becomes small, flabby and atrophy
Motor Neurons
Upper Motor Neurons (UMN) - Produce increased muscle tone (hypertonic) and reflexes can become hyperactive (cerebral palsy)
Lower Motor Neurons (LMN) - Produce decreased tone (hypotonic) and cause muscle to dystrophy (waste away)
Muscle Actions
Prime Mover - Muscle that causes a particular movement.
Synergist - Assist prime movers to move a muscle
Antagonist - Move muscles in the opposite way of the prime mover
When prime movers are moving a muscle, antagonist are relaxed to allow motion