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%).
What is adduction?
Moving a limb towards the midline of the body.
What happens if there is an imbalance of water and solute concentrations across the cell membrane?
Water will move to balance the concentrations, affecting cell size and integrity.
What does the term “proximal” mean in anatomical terminology?
Closer to the point of attachment or origin.
How do atoms, molecules, cells, and tissues relate to each other?
Atoms combine to form molecules, which interact to form cells that can secrete and regulate. These cells and extracellular materials and fluids combine to form tissues.
What responses are coordinated by the Heat-Gain centre when body temperature lowers?
Behavioral changes, vasoconstriction, reduced sweat production, shivering, and goosebumps.
What are the two main divisions of the human skeleton?
Axial skeleton and appendicular skeleton.
What is the role of Osteoblasts?
They produce new bone matrix.
What makes up the inorganic component of bone?
Hydroxyapatite and other calcium minerals; it makes bone hard and resistant to compression.
What is the difference in structure between compact and cancellous bone?
Compact bone has an osteon structure; cancellous bone has a trabecular structure.
What is the origin, insertion, and movement of the deltoid muscle?
Origin: Scapula and clavicle. Insertion: Deltoid tuberosity. Movement: Shoulder flexion (anterior fibers), abduction (lateral fibers), and extension (posterior fibers).
What is the role of Osteogenic cells?
They are stem cells that produce osteoblasts.
What happens at the knee during mid stance?
The knee moves from extension into slight flexion, with hamstrings and gastrocnemius as agonists.
What is the origin, insertion, and movement of the gluteus maximus?
Origin: Ilium and sacrum. Insertion: Femur. Movement: Hip extension.
What percentage of tissue in the human body is connective tissue?
45%
What are the functions of nervous tissue?
Conducts electrical impulses and carries information.
What occurs during repolarization?
Positive ions are removed from the cell, returning to resting membrane potential.
Describe the muscle activity at the hip during mid stance.
The hip continues moving into extension, with gluteus maximus and hamstrings as the agonists.
What muscles are active at the hip during early swing?
Iliopsoas and rectus femoris as agonists, with gluteus maximus and hamstrings controlling the swing rate.
What is the resting membrane potential?
The electrical gradient when the cell is at rest, with the inside of the cell more negatively charged than the outside.
What does the term “inferior” mean in anatomical terminology?
Below or towards the feet.
What is homeostasis?
It supports normal function of body systems by maintaining conditions in the internal environment through regulatory mechanisms.
What are transverse tubules (T-tubules) and their function?
Tube-like extensions of the sarcolemma that conduct electrical signals deep into the muscle fibre.
Which tissue allows information to be quickly sent around the body?
Nervous tissue.
What are the characteristics of fast muscle fibres?
They produce a lot of force quickly but fatigue quickly.
What is osmosis?
Movement of water across a membrane to equalize solute concentration.
What are the components of an osteon?
Central canal (with blood vessels and nerves), lamellae (cylinders of ECM), lacunae (for osteocytes), and canaliculi (channels for osteocytes).
Describe the pelvic girdle.
Made up of the two hip bones and the sacrum; supports weight-bearing.
What is bony congruence?
The sum of bone surfaces that form an articulation, requiring more soft tissue where there is less congruence.
What is the knee’s position during mid swing, and which muscles are active?
The knee is in flexion with hamstrings and gastrocnemius as agonists.
What are the three classes of levers in the body?
First-class (stabilizes joint position), second-class (overcomes heavy loads), and third-class (large range of movement and speed).
What is the sagittal plane?
The plane that divides the body into left and right sections.
What is the origin, insertion, and movement of the triceps surae (gastrocnemius and soleus)?
Origin: Femur condyles (gastrocnemius) and tibia/fibula (soleus). Insertion: Calcaneus via Achilles tendon. Movement: Knee flexion (gastrocnemius) and ankle plantarflexion.
What are the three types of muscle contractions?
Concentric (muscle shortens), eccentric (muscle lengthens), and isometric (muscle length stays the same).
What is the primary function of skeletal muscle?
To apply force to bones to control posture and body movements, mostly under voluntary control.
What are some adaptations for bipedalism in humans?
Hands-free movement, less stability in hands, and fingers adapted for manipulation and precision.
Describe the gross structure of bones and explain how they reflect their functions.
Compact bone is strong for force transmission; cancellous bone is light and spongy for shock absorption.
Describe the general principles of bone growth.
Bone grows in length at epiphyseal plates and in width through appositional growth involving osteoblasts and osteoclasts.
What happens to a cell in a hypertonic solution?
Water leaves the cell, causing it to shrink
How does the length-tension relationship affect muscle strength?
Each muscle has an optimal length where it is strongest, with changing overlap between actin and myosin filaments affecting strength.
Describe the structure and function of the skull.
Made up of the cranium and facial bones; protects the brain and supports sensory organs.
What is the origin, insertion, and movement of the tibialis anterior?
Origin: Tibia. Insertion: Tarsals. Movement: Ankle dorsiflexion.
What is the ankle’s position during late swing?
The ankle is in dorsiflexion, with tibialis anterior as the agonist and triceps surae stabilizing the joint for heel strike.
What are the two determinants of skeletal muscle force generation?
The number of muscle fibres recruited and the rate of muscle stimulation.
What does the term “distal” mean in anatomical terminology?
Farther from the point of attachment or origin.
What is flexion?
Decreasing the angle between two body parts.
Which tissue forms glands?
Epithelial tissue.
Describe the pectoral girdle.
Made up of the clavicle and scapula; provides stability and muscle attachments.
What is DFCT, and what are its characteristics?
Dense Fibrous Connective Tissue; contains fibroblasts, collagen, and some elastin, resists tension, and has little vascularity.
What is the function of fibrocartilage?
To resist tension and compression, act as a shock absorber, and deepen articular surfaces.
What is the correct anatomical position?
Upright, facing forwards, feet together, palms facing forwards.
What happens during bone remodelling?
Osteoblasts add bone matrix to the surface, and osteoclasts remove bone from the medullary cavity.
What is the role of the plantarflexors at the ankle during standing?
To stabilize the joint as the line of gravity pushes it into dorsiflexion, consuming energy.
What happens when many action potentials are fired in rapid sequence?
A sustained release of calcium, sustained actin-myosin interaction, and sustained contraction (summation).
Describe the structure and function of the rib cage.
Made up of ribs and sternum; protects major organs like the heart and lungs.
What is circumduction?
A combination of flexion, extension, abduction, and adduction.
What is the primary site of ion loss?
The kidney.
Which tissue is the most common in the body?
Muscle tissue (50%).
What does the term “medial” mean in anatomical terminology?
Closer to the midline of the body.
Describe a bone pathology related to lack of homeostasis.
Osteoporosis, caused by more Osteoclast activity than Osteoblast activity, leading to thinning trabeculae and increased fracture risk.
What is the primary function of muscle tissue?
Contracts to produce movement.
What does hypertonic mean?
Higher solute concentration outside the cell, causing water to leave the cell.
How do humans achieve energy-efficient standing?
By having specific anatomical features at joints that allow for minimal muscular support, mainly at the ankle joint.
Describe the knee’s movement and muscle activity during late swing.
The knee moves from flexion into extension to prepare for heel strike, with quadriceps femoris as the agonist.
What are the functions of connective tissue?
Fills internal spaces, provides structural support, stores energy, establishes a structural framework for the body, transports fluids and dissolved materials, protects delicate organs, supports, surrounds, and interconnects other types of tissues, stores energy (especially in the form of triglycerides), and defends the body from invading microorganisms.
What does the term “anterior” mean in anatomical terminology?
Towards the front of the body.
What percentage of a bone’s weight is cellular, and what are the types of cells involved?
2%; includes Osteogenic cells, Osteoblasts, Osteocytes, and Osteoclasts.
What is eversion?
Turning the sole of the foot away from the midline.
Describe long bones.
Longer than they are wide, with wider epiphyses and a longer diaphysis; act as levers for movement and are mostly limb bones.
What is the role of Osteocytes?
They recycle protein and minerals from the matrix.
At what point in the cross-bridge cycle does the myofilament slide?
When the myosin head uses its stored energy to pull on the actin filament.
What occurs at the hip during late stance (toe off)?
The hip is in extension with gluteus maximus and hamstrings as agonists.
What does the term “posterior” mean in anatomical terminology?
Towards the back of the body.
What is rotation in anatomical movement?
Movement around the long axis of a joint.
Where is smooth muscle found and is it under voluntary control?
Found in hollow organs (e.g., gut, blood vessels) and is not under voluntary control.
What is the role of Osteoclasts?
They remove bone matrix.
What are the three types of muscle tissue?
Skeletal muscle, cardiac muscle, and smooth muscle.
Describe irregular bones.
Various shapes and functions; they often have foramina (holes).
Which tissues would you find in your knee joint?
Connective tissue (including cartilage and bone), muscle tissue, and nervous tissue.
What is a chemical gradient?
Uneven distribution of molecules across a membrane.
What are movements in the sagittal plane?
Flexion and extension.
What are muscle fibres and how are they organized in skeletal muscles?
Individual muscle cells that gather into bundles called fascicles, which bundle into muscles.
What are the characteristics of slow muscle fibres?
They supply steady force and are slow to tire.
What are the classes of bones?
Long bones, short bones, flat bones, and irregular bones.
What is the role of tendons in skeletal muscles?
Connect muscles to bones.
What is the function of tendons?
To connect muscle to bone, facilitate and control movement, and transmit muscle contraction to bone.
How does the line of gravity affect the knee joint in bipedal standing?
It is anterior to the knee joint, pushing it into extension and locking it without energy expenditure.
What percentage of tissue in the human body is muscle tissue?
50%
Describe fibrous joints.
Made of DFCT, limit movement, provide stability (e.g., skull sutures).
What is the origin, insertion, and movement of the hamstrings?
Origin: Ischium and femur (biceps femoris). Insertion: Tibia (semimembranosus and semitendinosus) and fibula (biceps femoris). Movement: Hip extension and knee flexion/rotation.
What makes up the organic component of bone?
Collagen and ground substance (proteoglycans); it resists tension.
Which tissue can be divided into skeletal, cardiac, and smooth?
Muscle tissue.
What determines the function of a muscle?
The length, number, and arrangement of muscle fibers.
What responses are coordinated by the Heat-Loss centre when body temperature rises?
Behavioral changes, vasodilation, shunting of blood to the skin, sweat production, and respiratory heat loss.
What are the two types of bone tissue?
Compact bone and cancellous/trabecular bone.
Describe the functions of the skeletal system.
Support, movement, protection, storage of minerals, and red blood cell formation.
What is the main difference between the radius and ulna vs. the tibia and fibula?
The radius and ulna can supinate and pronate, allowing for wrist mobility, while the tibia and fibula provide stability with no pronation or supination.
What does hypotonic mean?
Higher solute concentration inside the cell, causing water to enter the cell.
What is the function of fibrous joints?
To limit movement and provide stability, found in sutures of the skull and distal tibiofibular joint.
What does the axial skeleton consist of and what is its function?
Consists of the skull, vertebral column, and rib cage; it protects vital organs.
What is feedback in homeostasis?
When a controlled variable moves too far from the set point and the body responds to bring it back to normal.
How does bone grow in width?
Through appositional growth; osteoblasts add bone matrix to the surface, and osteoclasts remove bone matrix from the inside.
How do male and female pelvises differ?
Female pelvises have a more circular pelvic cavity, a larger pubic angle, and a more open pelvic outlet to accommodate childbirth.
Why is knowing terminology important in anatomy?
It allows effective communication and avoids vague descriptions or directions.
How does the ankle move during early stance?
The ankle moves from dorsiflexion to plantarflexion with triceps surae as the agonist and tibialis anterior controlling the foot drop rate.
What is the origin, insertion, and movement of the biceps brachii?
Origin: Scapula. Insertion: Radial tuberosity. Movement: Flexion at the shoulder and elbow, supination at the radioulnar joints.
What is recruitment in muscle force generation?
The process of activating more muscle fibres to produce more force.
Define the basic pattern of the gait cycle.
The gait cycle includes the stance phase, swing phase, and transitions like heel strike and toe off.
What are the key soft tissues involved in joint movement?
Cartilage (hyaline and fibrocartilage) and DFCT (ligaments, tendons, and joint capsules).
Describe cartilaginous joints.
Made of fibrocartilage, allow some movement (e.g., intervertebral discs, pubic symphysis).
How do skeletal muscles cause movement at synovial joints?
By attaching to bones via tendons and shortening to create movement.
Define terms used to describe spatial and positional relationships of structures.
Anterior/posterior, superior/inferior, medial/lateral, proximal/distal, superficial/deep.
Where is compact bone found and what is its function?
Found in the diaphysis; it is strong and good at transmitting force in one direction.
What does the term “superior” mean in anatomical terminology?
Above or towards the head
What are the connections between the limbs and the axial skeleton?
The pectoral (shoulder) girdle and the pelvic girdle.
What is the sarcoplasmic reticulum (SR) and its function?
A membrane network that stores and releases calcium (Ca2+) during muscle contraction.
Describe the structure of cancellous bone.
Contains trabeculae (struts of lamella bone), marrow in cavities, and osteocytes in lacunae or on the surface.
What are the functions of epithelial tissue?
Covers exposed surfaces, lines internal passageways and chambers, forms secretory glands, provides physical protection, controls permeability, provides sensation, and produces specialized secretions.
What structures are included in epithelial tissue?
Epithelia and glands (exocrine and endocrine).
What is the origin, insertion, and movement of the triceps brachii?
Origin: Scapula and humerus. Insertion: Olecranon process of ulna. Movement: Extension at the shoulder and elbow.
Where is cardiac muscle located and is it under voluntary control?
Located only in the heart and is not under voluntary control.
What is an electrical gradient?
Uneven distribution of charges across a membrane.
What percentage of tissue in the human body is epithelial tissue?
3%
What is the ankle’s position during late stance, and which muscle is the agonist?
The ankle is in full plantarflexion with triceps surae as the agonist for propulsion.
What are some examples of set-points in homeostasis?
Temperature, ion concentrations (calcium, potassium, sodium), blood sugar levels, and fluid balance.
