2023F-BHSC 1000 Module 6 Mobility Class 1.pdf

Module 6 Mobility BHSC 1000 Class 1: Concept Introduction and Osteoporosis 1 Learning Outcomes 1. Define the concept and describe the scope of mobility. 2. Describe the requirements for mobility and the function of neurologic and musculoskeletal structures related to mobility. 3. Identify conditi...

Module 6 Mobility BHSC 1000 Class 1: Concept Introduction and Osteoporosis 1 Learning Outcomes 1. Define the concept and describe the scope of mobility. 2. Describe the requirements for mobility and the function of neurologic and musculoskeletal structures related to mobility. 3. Identify conditions causing impaired mobility. 4. Identify risk factors for impaired mobility in an older adult. 5. Describe the pathophysiology of osteoporosis. 2 Mobility The state or quality of being mobile or movable. • Involves musculoskeletal and nervous systems • Necessary for the performance of activities of daily living (ADLs) 3 Scope of Mobility • Gross simple movements • Fine complex movements • Coordination Limitation in physical movement Inability to move 4 Under what condition might someone have partial mobility? 5 Requirements for Mobility Previously, we learned about the concepts of perfusion and gas exchange. How are the three concepts connected? Perfusion Mobility Gas Exchange 7 Facilitates venous return, improves circulation and strengthens cardiovascular health Delivers blood to the bones and muscles for nourishment and waste removal Mobility Perfusion Moves O2 and CO2 into and out of blood Supports aerobic respiration and sustained muscle activity Improves chest cavity expansion and lung capacity Delivers blood to the lungs for nourishment and gas exchange Gas Exchange 8 Requirements for Mobility 1. 2. 3. 4. 5. Bone stability Skeletal muscle strength Joint function (cartilage, tendons and ligaments) Neurological function (brain, spinal cord, nerves) Nutrition Conditions that affect any of the above will affect mobility. 9 Aging on Mobility Osteoporosis International (2019) volume 30, pages 1911–1922. Some degree of impaired mobility is observed in chronic illnesses. 10 Risk Factors for Impaired Mobility in Older Adults 1. Skeletal stability: reduced bone density 2. Muscle strength: reduced muscle mass and tone 3. Joint function: more rigid and fragile cartilage What about… 4. Neurological function 5. Nutrition 11 Bone Tissue Compact Bone Spongy Bone (Cortical) (Trabecular or Cancellous) • Strong and dense • Composed of structural units called osteons • Light and porous • Contains lattice-shaped meshwork called trabeculae 13 Bone Tissue Cell Types Extracellular Matrix Organic matrix (osteoid) • Collagen and non-collagenous proteins Inorganic matrix (minerals + water) • Calcium • Phosphate • Carbonate • Other minerals 14 Bone Remodeling The dynamic process in which existing bone is broken down (bone resorption) and replaced by new bone (bone deposition). Maintain and repair Adaptation to stress Mineral regulation 15 Bone Remodeling Question 1 In which part of the bone does remodelling occur? A. B. C. D. The trabecular surfaces of spongy bone The centre canals of osteons in compact bone The surfaces of both spongy and compact bones The weight-baring bones such as the femur and humerus 16 Bone Remodeling 17 Bone Remodeling 2. Reversal (poorly understood): The transitional period between bone resorption and bone formation. 3. Formation: Osteoblasts secrete osteoid (organic framework of bones); some osteoblasts differentiate into osteocytes. 1. Resorption: Osteoclasts attach to bone surface and remove bone matrix. 4. Mineralization: Osteoblasts deposit minerals in the formed organic framework. 18 Nat Rev Mol Cell Biol. 2020 Nov;21(11):696-711. Osteoporosis 20 Osteoporosis A systemic skeletal disorder characterized by low bone density and micro-architectural deterioration. • Silent • Increased risk of fracture • Imbalance in bone remodeling: Bone resorption exceeds bone deposition 21 Osteoporosis Epidemiology Source: Osteoporosis Canada Source: Government of Canada, 2021 22 Risk Factors of Osteoporosis Non-modifiable • • • • • Age Female Genetics (small body frame) Family history Race (Asians, some European Caucasians) Modifiable • • • • • • • Peak bone mass Low Ca2+ or Vitamin D (lack of sunlight) Physical inactivity Hormone imbalance (hyperparathyroidism) Medications (glucocorticoids) Alcohol Smoking 23 Age-related Changes in Bone Mass Peak bone mass is the maximum bone mass achieved in life. After peak bone mass is achieved, bone resorption slowly exceeds bone formation. • Bones become weaker and more brittle Puberty: Bone formation exceeds bone resorption. • Bones grow larger and denser 24 What factors influence the peak bone mass of a person? 25 Calcium Homeostasis 2 Blood Ca2+ level is maintained by parathyroid hormone (PTH) and activated vitamin D (calcitriol). 1 1. Bones release Ca2+ 2. Kidneys reabsorb Ca2+ 3. Small intestine absorbs Ca2+ 3 27 Sex-related Changes in Bone Mass Females develop lower peak bone mass. Menopause in females significantly decreases bone mass due to estrogen deficiency. Females start with lower bone mass partly due to smaller bone structure. 29 Sex-related Changes in Bone Mass Estrogens • Growth plate closure • Regulate rate of bone remodeling • Promote collagen formation Androgens • Increase cortical bone thickness and peak bone mass • Convert into estrogens 30 Pathogenesis of Osteoporosis The rate of bone remodeling increases. Bone resorption exceeds bone deposition. 31 Pathogenesis of Osteoporosis Both spongy and compact bones are affected. Bone loss occurs earlier and to a greater extent in spongy bones than compact bones due to more surface area for remodeling. 32 Clinical Manifestation There is no clinical manifestation until a fracture occurs. • Spontaneous or due to minor trauma Complications of fractures: • Pain from fracture • Deformity (kyphosis) • Additional falls 33 Osteoporosis Early detection is key. • Assess bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) scan • T Score: BMD compared to that of a healthy 30year-old adult Purposes: • Detects osteoporosis before a fracture • Determines rate of bone loss • Monitors the response to therapy 34 FYI Paget disease of bone • Increased bone remodeling, resulting in overgrowth of disorganized bone tissues • Believed to be due to defective osteoclasts Osteomalacia • Decreased bone mineralization during bone remodeling (abnormal ratio of organic and inorganic matrix) • Mainly due to vitamin D deficiency or abnormal vitamin D metabolism These disorders can co-exist with osteoporosis. 35 End of Class 1 37