Lectures 1-10: Bone and Biomechanics Flashcards
How does bone maintain homeostasis?
By balancing Osteoblast and Osteoclast activity to regulate bone formation and destruction.
Where are Na+ and K+ ions located at rest?
Na+ is outside the cell, and K+ is inside the cell.
What occurs during depolarization?
Positive ions enter the cell, signaling excitable cells.
What percentage of tissue in the human body is nervous tissue?
2%
What is dorsiflexion?
Bringing the toes up towards the face.
Describe the ankle’s position and muscle activity during mid swing.
The ankle is in dorsiflexion to allow toe clearance, with tibialis anterior as the agonist.
What muscles stabilize the knee during early stance?
The quadriceps femoris, hamstrings, and gastrocnemius.
What is the coronal plane?
The plane that divides the body into front and back sections.
What is required to maintain bone homeostasis?
Adequate dietary calcium and moderate exercise.
Identify the major bones of the skeleton, and understand why/how some are sexually dimorphic.
Major bones include the skull, vertebral column, rib cage, and limb bones. Sexual dimorphism is seen in the pelvis to accommodate childbirth in females.
What is the ankle’s position during early swing?
The ankle is in dorsiflexion to allow toe clearance, with tibialis anterior as the agonist.
What does the appendicular skeleton consist of and what is its function?
Consists of the limb bones; it is important for movement.
What is inversion?
Turning the sole of the foot towards the midline.
What anatomical feature helps maintain a stable, upright stance without energy expenditure at the hip?
The line of gravity being posterior to the hip joint, pushing it into extension and tightening the ligaments.
What is the function of trabeculae in cancellous bone?
Resist force from multiple directions and spread force distally.
How is bone homeostasis maintained?
Balance between Osteoblast and Osteoclast activity, allowing constant bone formation and destruction.
Define and demonstrate terms of movements as related to joints.
Flexion/extension (sagittal plane), abduction/adduction (coronal plane), circumduction, rotation, pronation, and supination.
Describe the microanatomy of tissues in joints.
Hyaline cartilage resists compression; fibrocartilage resists tension and compression; DFCT resists tension.
What are the roles of agonist, antagonist, stabilizer, and neutralizer muscles?
Agonist creates movement, antagonist opposes movement, stabilizer holds a joint still, neutralizer prevents unwanted movement.
Define tissue and structure.
Tissue: Cells grouped together in an organized manner (e.g., DFCT). Structure: Something formed of a tissue (e.g., ligament).
What is extension?
Increasing the angle between two body parts.
Describe flat bones.
Thin plates of compact bone (with some cancellous); they function for muscle attachment and protection (e.g., scapula, skull, sternum).
Describe short bones.
Nearly equal in width and length, mostly cancellous bone; they are weight-bearing (e.g., carpals and tarsals).
What is the role of triceps surae during mid stance?
It continues to move the ankle into plantarflexion.
Describe the structure of limb bones.
Each limb has a single proximal long bone (humerus/femur), two distal long bones (ulna and radius/tibia and fibula), and bones of the hands and feet.
Where does ion absorption occur?
Across the epithelial lining of the small intestine and colon.
What is plantarflexion?
Pointing the toes towards the ground.
Describe the knee’s position and muscle activity during late stance.
The knee is in extension with hamstrings and gastrocnemius preparing for the next movement.
What does the term “lateral” mean in anatomical terminology?
Farther from the midline of the body.
What are sarcomeres and what do they contain?
Repeating units in myofibrils made of contractile proteins: actin (thin filaments) and myosin (thick filaments).
What occurs at the hip during late swing?
The hip remains in flexion, with iliopsoas and rectus femoris as agonists.
Where are ion reserves primarily located?
In the bones of the skeleton.
Where is cancellous bone found and what is its function?
Found in the epiphyses; it is light, spongy, and good for shock absorption.
What does isotonic mean?
The solute concentration is balanced between the inside and outside of the cell.
What are myofibrils and what are they made of?
Bundles within muscle fibres made of repeating units called sarcomeres.
Describe the three types of joints.
Fibrous (least movement, provides stability), Cartilaginous (some movement, connected by fibrocartilage), and Synovial (most movement, made of various tissues).
What body parts are included in the upper limb?
Arm, forearm, and hand.
What is an osteon, and what is its function?
A lengthwise unit in compact bone; provides a pathway for nutrients to cells in the ECM.
What is the transverse plane?
The plane that divides the body into top and bottom sections.
What are the two extracellular components of bone?
Organic (33%) and inorganic (67%).
What are the functions of the skeletal system?
Support, movement, protection, storage of minerals, and red blood cell formation.
What are the two key proteins that make up the myofilament?
Actin and myosin.
What is feedforward in homeostasis?
Anticipation of an event that will alter a controlled variable, leading to actions that minimize the effect.
What types of connective tissue are there?
Connective tissue proper (loose: areolar, adipose, reticular; dense: dense regular, dense irregular, elastic), fluid connective tissue (blood and lymph), and supporting connective tissues (cartilage: hyaline, elastic, fibrocartilage; bone).
What event causes the cross-bridge to be released?
The binding of ATP to the myosin head.
What is the function of cartilaginous joints?
To allow some movement, found in intervertebral discs and pubic symphysis.
Where is the primary ossification center located, and what does it do?
In the diaphysis (shaft); it develops bone at different times.
What happens to a cell in a hypotonic solution?
Water enters the cell, causing it to expand and possibly burst.
What is abduction?
Moving a limb towards the midline of the body.
What is tetanus in muscle contraction?
The maximal signaling and contraction capability of the muscle.
What event allows a cross-bridge to form?
The presence of calcium.
Describe the different classes of bone in the human skeleton and explain how their shape relates to function.
Long bones (movement), short bones (weight-bearing), flat bones (muscle attachment and protection), irregular bones (varied functions).
What do muscle fibres, fascicles, and muscles contain?
Many blood vessels and nerves, sheathed in connective tissue.
What is pronation?
Turning the palms to face posteriorly
What is the function of synovial joints?
To allow a lot of movement, found in most appendicular skeleton joints.
What happens at the hip during mid swing?
The hip remains in flexion, with iliopsoas and rectus femoris as agonists, and gluteus maximus and hamstrings controlling the swing rate.
What is the sarcolemma?
The cell membrane of a muscle fibre.
What does the term “superficial” mean in anatomical terminology?
Closer to the surface of the skin.
What is the origin, insertion, and movement of the iliopsoas?
Origin: Iliac fossa and lumbar vertebrae. Insertion: Femur. Movement: Hip flexion.
What does the term “deep” mean in anatomical terminology?
Farther from the surface of the skin.
Where are the secondary ossification centers located, and what is their function?
In the epiphyses; they enable bone growth in length through the epiphyseal/growth plate.
What is the function of bone cells?
They respond to external forces, change shape, remodel, and repair themselves.
What is supination?
Turning the palms to face anteriorly.
What is the origin, insertion, and movement of the quadriceps femoris?
Origin: Ilium (rectus femoris) and femur (vastus muscles). Insertion: Tibial tuberosity. Movement: Hip flexion (rectus femoris) and knee extension.
Describe the microscopic structure of bones.
Compact bone has osteons with central canals, lamellae, lacunae, and canaliculi; cancellous bone has trabeculae with marrow and osteocytes.
Describe the structure of compact bone.
Dense outer surfaces (periosteum), visible foramina for blood supply, made up of osteons with circumferential lamellae.
Which tissue includes blood and lymph?
Connective tissue.
Describe the knee’s movement and muscle activity during early swing.
The knee is in flexion to lift the foot, with hamstrings and gastrocnemius as agonists.
What happens to a cell in an isotonic solution?
No net flow of water, cell remains stable.
What causes Osteoporosis?
More Osteoclast activity than Osteoblast activity, leading to a loss of cortical bone and thinning of trabeculae.
What creates the chemical and electrical gradients?
The distribution of Na+ and K+ ions across the cell membrane.
What is the function of ligaments?
To connect bone to bone, resist tension, and restrict movement away from themselves.
Describe the structure and function of the vertebral column.
Made up of 24 vertebrae, sacrum, and coccyx; supports the head and trunk, and allows muscle and ligament attachments.
What occurs at the hip during early stance?
The hip moves from flexion into extension with the help of gluteus maximus and hamstrings.
What is the difference between passive ion channels and active pumps?
Passive channels allow ions to move down their gradient, active pumps use energy to move ions against their gradient.
What are movements in the coronal plane?
Abduction and adduction.
How many bones are in the hands and feet?
Hands: 27 bones each (8 carpals, 5 metacarpals, 14 phalanges); Feet: 26 bones each (7 tarsals, 5 metatarsals, 14 phalanges).
What is the function of hyaline cartilage?
To resist compression, mold bone surfaces at joints, and enable frictionless movement.
Who is more likely to develop Osteoporosis and why?
Biological females, especially postmenopausal, due to a loss of oestrogen and lifestyle factors (lack of exercise, poor nutrition, alcohol, smoking).
What body parts are included in the lower limb?
Thigh, leg, and foot.
What is diffusion?
Movement of molecules from high to low concentration.
Which tissue is the least common in the body?
Nervous tissue (2%).