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Questions and Answers
What is a characteristic of the plasma membrane?
Which cellular process does NOT require energy?
Which of the following is a component of cell theory?
Which of these extracellular fluids is responsible for transporting nutrients and waste in the bloodstream?
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Which organelle is primarily responsible for energy production in the cell?
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What does anatomy primarily focus on?
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Which term describes the process that enhances a stimulus in the body?
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How does the body maintain homeostasis?
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What is the primary function of monosaccharides?
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Which statement is true regarding the first law of thermodynamics?
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What is the role of buffers in the body?
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Which of the following is a characteristic of water?
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What type of energy is associated with chemical bonds?
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What is anatomy?
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What is the study of physiology?
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What is homeostasis?
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Which of the following is a type of energy?
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The first law of thermodynamics states that energy can be created and destroyed.
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Match the following carbohydrate types with their examples:
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What are the basic components of a cell?
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What does the plasma membrane do?
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What is the function of water in the human body?
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The smallest unit of life is the ______.
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What is anatomy?
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What does physiology study?
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What is homeostasis?
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Negative feedback enhances the stimulus in the body.
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What is the function of phospholipids?
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What are the three basic components of a cell?
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Which of the following correctly pairs the nitrogenous bases in DNA?
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What type of tissue is responsible for protection, absorption, and secretion?
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All organisms are made up of one cell according to cell theory.
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What is anatomy?
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What is physiology?
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What is homeostasis?
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Which term means 'towards the head'?
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The normal body temperature is 98.7 degrees Fahrenheit.
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What is one of the four types of energy?
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What does 'D2O' refer to?
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What is the function of phospholipids in the cell membrane?
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Which type of tissue is primarily responsible for absorption and secretion?
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The pH scale measures the potential of __________.
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What is the principle of complementary?
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What is anatomy?
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What is physiology?
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What is homeostasis?
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Which of the following best describes negative feedback?
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The superior direction refers to being away from the head.
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Which of the following is a type of energy?
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What is D2O and its significance?
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The process of maintaining a stable internal environment is called ______.
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What does the pH scale measure?
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Match the types of carbohydrates to their examples:
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All organisms are made up of cells according to cell theory.
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What is a phospholipid?
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What are the three basic components of a cell?
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What is the rate of cell division in hyperplasia?
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Define Wolff's Law.
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Which type of bone contains trabeculae?
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In which zone of the epiphysis do cells enlarge or get bigger?
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Which type of incomplete fracture is characterized by the bone flexing causing only one side of the shaft to fracture?
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During which stage of fracture repair do fibroblasts secrete collagen to span the break while osteoblasts lay down a soft bony matrix?
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Define Wolff’s Law.
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Which type of bone contains trabeculae?
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In which zone of the epiphysis do cells enlarge or get bigger?
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Which type of incomplete fracture is characterized by the bone flexing causing only one side of the shaft to fracture?
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During which stage of fracture repair do fibroblasts secrete collagen to span the break while osteoblasts lay down a soft bony matrix?
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Define Wolff's Law.
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Which type of bone contains trabeculae?
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In which zone of the epiphysis do cells enlarge or get bigger?
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Which type of incomplete fracture is characterized by the bone flexing causing only one side of the shaft to fracture?
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During which stage of fracture repair do fibroblasts secrete collagen to span the break while osteoblasts lay down a soft bony matrix?
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Study Notes
Anatomy and Physiology
- Anatomy refers to the structure of body parts and their interrelationship.
- Microscopic anatomy focuses on structures too small to be seen with the naked eye.
- Developmental anatomy studies the growth and changes in anatomical and physiological features throughout life.
- Physiology examines how body parts function and collaborate to sustain life.
- Normal body temperature is approximately 98.7°F (37°C).
Homeostasis
- Homeostasis maintains a relatively stable internal environment despite external changes.
- Negative feedback reduces physiological effects, such as regulating blood sugar and body temperature.
- Positive feedback enhances physiological responses, notably during labor contractions and blood clotting.
Anatomical Terminology
- Superior: towards the head
- Inferior: away from the head (also known as caudal)
- Anterior: towards the front (also called ventral)
- Posterior: towards the back (also called dorsal)
- Medial: towards the midline
- Lateral: away from the midline
Chemistry Fundamentals
- Energy is the capacity to do work; it exists in four forms: chemical, mechanical, electrical, and electromagnetic.
- The First Law of Thermodynamics states energy cannot be created or destroyed but can be transformed.
- D₂O is an isotope used in tracking excretion and carbon dating.
- Radioisotopes have the same chemical formula but different structural formulas, useful in imaging as staining agents.
Biological Molecules
- Water is cohesive due to hydrogen bonding, serving as a universal solvent with high heat capacity and vaporization point.
- pH measures the potential of hydrogen ions; buffers stabilize pH levels by converting strong acids/bases into weaker forms.
- Monosaccharides include glucose, fructose, and galactose; disaccharides include sucrose, lactose, and maltose; polysaccharides consist of glycogen, starch, and cellulose.
- Functions of lipids include energy storage, insulation, and organ protection; key types include phospholipids and steroids.
Cell Theory
- Cell theory posits that the cell is the smallest unit of life, all organisms consist of cells, and cells arise from pre-existing cells.
- Principle of Complementarity suggests that structure and function are interrelated.
- Basic components of a cell include the plasma membrane, cytoplasm, and nucleus.
Extracellular Materials
- Types of extracellular fluids include blood plasma, interstitial fluid, and cerebrospinal fluid.
- Cellular secretions encompass substances like saliva, mucus, and gastric juice.
- The extracellular matrix is primarily composed of the intercellular 'glue'.
Plasma Membrane
- Composed of phospholipids, glycolipids, and cholesterol, ensuring stability and selective permeability.
- Transport across the membrane can be passive or active:
- Passive transport requires no energy and includes diffusion and osmosis.
- Active transport involves energy input (e.g., Na/K pumps).
- Vesicular transport methods include endocytosis (into cells) and exocytosis (out of cells).
Organelles
- Key organelles include the endoplasmic reticulum, mitochondria, Golgi apparatus, ribosomes, and lysosomes.
- Interphase is characterized by cell growth and preparation for division, while chromosomes form during prophase when chromatin condenses.
Nucleotide Pairing
- Nucleotide pairing includes A with T and C with G in DNA structure.
Anatomy and Physiology
- Anatomy examines body structures and their relationships.
- Microscopic anatomy studies structures not visible to the naked eye.
- Developmental anatomy analyzes anatomical and physiological changes throughout life.
- Physiology focuses on the functions of body parts and life-sustaining activities.
Homeostasis
- Homeostasis is the maintenance of a stable internal environment despite external changes.
- Negative feedback mechanisms reduce the body's reaction, as seen in blood sugar and temperature regulation.
- Positive feedback mechanisms enhance stimuli, evident in labor contractions and blood clotting.
Anatomical Terminology
- Superior: toward the head.
- Inferior: away from the head (also called caudal).
- Anterior: towards the front of the body (also called ventral).
- Posterior: towards the back of the body (also called dorsal).
- Medial: towards the midline of the body.
- Lateral: away from the midline.
Chemistry Basics
- Energy is the capacity to perform work and exists in four forms: chemical, mechanical, electrical, electromagnetic.
- The first law of thermodynamics states energy cannot be created or destroyed, only converted.
- D2O is an isotope used for tracking excretion and in carbon dating; radioisotopes have the same formula but different structures, useful in imaging and staining.
- Water's cohesiveness is due to hydrogen bonding.
Organic Compounds
- Organic compounds contain carbon.
- Monosaccharides: glucose, fructose, galactose.
- Disaccharides: sucrose, lactose, maltose.
- Polysaccharides: glycogen, starch, cellulose, which serve as energy storage, insulation, and organ protection.
Water Properties
- Water is a universal solvent with a high heat capacity, high vaporization point, and a reactive nature.
- It cushions the brain, potentially preventing trauma.
- pH indicates the level of hydrogen ions, influencing acidity/basicity.
pH and Buffers
- Buffers help convert strong acids/bases into weaker ones, regulating pH stability.
Cell Theory
- All organisms consist of cells, which stem from pre-existing cells.
- Basic components of cells include the plasma membrane, cytoplasm, and nucleus.
- Extracellular fluids include blood plasma, interstitial fluid, and cerebrospinal fluid.
Plasma Membrane Structure
- Composed of phospholipids, glycolipids, and cholesterol, which maintains membrane stability.
- Selectively permeable; substances enter through passive (no energy) and active (requires energy) transport methods.
Active Transport and Vesicular Transport
- Active transport includes sodium-potassium pumps.
- Vesicular transport can involve endocytosis (into the cell) and exocytosis (out of the cell).
Organelles
- Key organelles include the endoplasmic reticulum, mitochondria, Golgi apparatus, ribosomes, and lysosomes.
Cell Division
- Interphase prepares the cell for division; DNA is replicated.
- Chromatin condenses into chromosomes during prophase and aligns during metaphase.
- RNA carries genetic information from the DNA to the ribosome for protein synthesis.
Tissue Types
- Epithelial tissue functions in protection, absorption, filtration, excretion, secretion, and sensory reception.
- Features include polarity (top apical layer and bottom basal layer), specialized contacts, support from connective tissue, and regeneration ability.
- Tissue classes include epithelium characterized by the number of layers and cell shape.
Anatomy and Physiology
- Anatomy examines body structures and their relationships.
- Microscopic anatomy studies structures not visible to the naked eye.
- Developmental anatomy analyzes anatomical and physiological changes throughout life.
- Physiology focuses on the functions of body parts and life-sustaining activities.
Homeostasis
- Homeostasis is the maintenance of a stable internal environment despite external changes.
- Negative feedback mechanisms reduce the body's reaction, as seen in blood sugar and temperature regulation.
- Positive feedback mechanisms enhance stimuli, evident in labor contractions and blood clotting.
Anatomical Terminology
- Superior: toward the head.
- Inferior: away from the head (also called caudal).
- Anterior: towards the front of the body (also called ventral).
- Posterior: towards the back of the body (also called dorsal).
- Medial: towards the midline of the body.
- Lateral: away from the midline.
Chemistry Basics
- Energy is the capacity to perform work and exists in four forms: chemical, mechanical, electrical, electromagnetic.
- The first law of thermodynamics states energy cannot be created or destroyed, only converted.
- D2O is an isotope used for tracking excretion and in carbon dating; radioisotopes have the same formula but different structures, useful in imaging and staining.
- Water's cohesiveness is due to hydrogen bonding.
Organic Compounds
- Organic compounds contain carbon.
- Monosaccharides: glucose, fructose, galactose.
- Disaccharides: sucrose, lactose, maltose.
- Polysaccharides: glycogen, starch, cellulose, which serve as energy storage, insulation, and organ protection.
Water Properties
- Water is a universal solvent with a high heat capacity, high vaporization point, and a reactive nature.
- It cushions the brain, potentially preventing trauma.
- pH indicates the level of hydrogen ions, influencing acidity/basicity.
pH and Buffers
- Buffers help convert strong acids/bases into weaker ones, regulating pH stability.
Cell Theory
- All organisms consist of cells, which stem from pre-existing cells.
- Basic components of cells include the plasma membrane, cytoplasm, and nucleus.
- Extracellular fluids include blood plasma, interstitial fluid, and cerebrospinal fluid.
Plasma Membrane Structure
- Composed of phospholipids, glycolipids, and cholesterol, which maintains membrane stability.
- Selectively permeable; substances enter through passive (no energy) and active (requires energy) transport methods.
Active Transport and Vesicular Transport
- Active transport includes sodium-potassium pumps.
- Vesicular transport can involve endocytosis (into the cell) and exocytosis (out of the cell).
Organelles
- Key organelles include the endoplasmic reticulum, mitochondria, Golgi apparatus, ribosomes, and lysosomes.
Cell Division
- Interphase prepares the cell for division; DNA is replicated.
- Chromatin condenses into chromosomes during prophase and aligns during metaphase.
- RNA carries genetic information from the DNA to the ribosome for protein synthesis.
Tissue Types
- Epithelial tissue functions in protection, absorption, filtration, excretion, secretion, and sensory reception.
- Features include polarity (top apical layer and bottom basal layer), specialized contacts, support from connective tissue, and regeneration ability.
- Tissue classes include epithelium characterized by the number of layers and cell shape.
Anatomy and Physiology
- Anatomy examines body structures and their relationships.
- Microscopic anatomy studies structures not visible to the naked eye.
- Developmental anatomy analyzes anatomical and physiological changes throughout life.
- Physiology focuses on the functions of body parts and life-sustaining activities.
Homeostasis
- Homeostasis is the maintenance of a stable internal environment despite external changes.
- Negative feedback mechanisms reduce the body's reaction, as seen in blood sugar and temperature regulation.
- Positive feedback mechanisms enhance stimuli, evident in labor contractions and blood clotting.
Anatomical Terminology
- Superior: toward the head.
- Inferior: away from the head (also called caudal).
- Anterior: towards the front of the body (also called ventral).
- Posterior: towards the back of the body (also called dorsal).
- Medial: towards the midline of the body.
- Lateral: away from the midline.
Chemistry Basics
- Energy is the capacity to perform work and exists in four forms: chemical, mechanical, electrical, electromagnetic.
- The first law of thermodynamics states energy cannot be created or destroyed, only converted.
- D2O is an isotope used for tracking excretion and in carbon dating; radioisotopes have the same formula but different structures, useful in imaging and staining.
- Water's cohesiveness is due to hydrogen bonding.
Organic Compounds
- Organic compounds contain carbon.
- Monosaccharides: glucose, fructose, galactose.
- Disaccharides: sucrose, lactose, maltose.
- Polysaccharides: glycogen, starch, cellulose, which serve as energy storage, insulation, and organ protection.
Water Properties
- Water is a universal solvent with a high heat capacity, high vaporization point, and a reactive nature.
- It cushions the brain, potentially preventing trauma.
- pH indicates the level of hydrogen ions, influencing acidity/basicity.
pH and Buffers
- Buffers help convert strong acids/bases into weaker ones, regulating pH stability.
Cell Theory
- All organisms consist of cells, which stem from pre-existing cells.
- Basic components of cells include the plasma membrane, cytoplasm, and nucleus.
- Extracellular fluids include blood plasma, interstitial fluid, and cerebrospinal fluid.
Plasma Membrane Structure
- Composed of phospholipids, glycolipids, and cholesterol, which maintains membrane stability.
- Selectively permeable; substances enter through passive (no energy) and active (requires energy) transport methods.
Active Transport and Vesicular Transport
- Active transport includes sodium-potassium pumps.
- Vesicular transport can involve endocytosis (into the cell) and exocytosis (out of the cell).
Organelles
- Key organelles include the endoplasmic reticulum, mitochondria, Golgi apparatus, ribosomes, and lysosomes.
Cell Division
- Interphase prepares the cell for division; DNA is replicated.
- Chromatin condenses into chromosomes during prophase and aligns during metaphase.
- RNA carries genetic information from the DNA to the ribosome for protein synthesis.
Tissue Types
- Epithelial tissue functions in protection, absorption, filtration, excretion, secretion, and sensory reception.
- Features include polarity (top apical layer and bottom basal layer), specialized contacts, support from connective tissue, and regeneration ability.
- Tissue classes include epithelium characterized by the number of layers and cell shape.
Anatomy and Physiology
- Anatomy examines body structures and their relationships.
- Microscopic anatomy studies structures not visible to the naked eye.
- Developmental anatomy analyzes anatomical and physiological changes throughout life.
- Physiology focuses on the functions of body parts and life-sustaining activities.
Homeostasis
- Homeostasis is the maintenance of a stable internal environment despite external changes.
- Negative feedback mechanisms reduce the body's reaction, as seen in blood sugar and temperature regulation.
- Positive feedback mechanisms enhance stimuli, evident in labor contractions and blood clotting.
Anatomical Terminology
- Superior: toward the head.
- Inferior: away from the head (also called caudal).
- Anterior: towards the front of the body (also called ventral).
- Posterior: towards the back of the body (also called dorsal).
- Medial: towards the midline of the body.
- Lateral: away from the midline.
Chemistry Basics
- Energy is the capacity to perform work and exists in four forms: chemical, mechanical, electrical, electromagnetic.
- The first law of thermodynamics states energy cannot be created or destroyed, only converted.
- D2O is an isotope used for tracking excretion and in carbon dating; radioisotopes have the same formula but different structures, useful in imaging and staining.
- Water's cohesiveness is due to hydrogen bonding.
Organic Compounds
- Organic compounds contain carbon.
- Monosaccharides: glucose, fructose, galactose.
- Disaccharides: sucrose, lactose, maltose.
- Polysaccharides: glycogen, starch, cellulose, which serve as energy storage, insulation, and organ protection.
Water Properties
- Water is a universal solvent with a high heat capacity, high vaporization point, and a reactive nature.
- It cushions the brain, potentially preventing trauma.
- pH indicates the level of hydrogen ions, influencing acidity/basicity.
pH and Buffers
- Buffers help convert strong acids/bases into weaker ones, regulating pH stability.
Cell Theory
- All organisms consist of cells, which stem from pre-existing cells.
- Basic components of cells include the plasma membrane, cytoplasm, and nucleus.
- Extracellular fluids include blood plasma, interstitial fluid, and cerebrospinal fluid.
Plasma Membrane Structure
- Composed of phospholipids, glycolipids, and cholesterol, which maintains membrane stability.
- Selectively permeable; substances enter through passive (no energy) and active (requires energy) transport methods.
Active Transport and Vesicular Transport
- Active transport includes sodium-potassium pumps.
- Vesicular transport can involve endocytosis (into the cell) and exocytosis (out of the cell).
Organelles
- Key organelles include the endoplasmic reticulum, mitochondria, Golgi apparatus, ribosomes, and lysosomes.
Cell Division
- Interphase prepares the cell for division; DNA is replicated.
- Chromatin condenses into chromosomes during prophase and aligns during metaphase.
- RNA carries genetic information from the DNA to the ribosome for protein synthesis.
Tissue Types
- Epithelial tissue functions in protection, absorption, filtration, excretion, secretion, and sensory reception.
- Features include polarity (top apical layer and bottom basal layer), specialized contacts, support from connective tissue, and regeneration ability.
- Tissue classes include epithelium characterized by the number of layers and cell shape.
Chemical Makeup of Bone
- Bone is comprised of organic and inorganic components.
- Organic components include osteoprogenitor cells, osteoblasts, osteocytes, and osteoclasts, and osteoids.
- Inorganic components consist of mineral salts, mainly calcium phosphate, contributing to 65% of bone mass.
- Mineral salts provide hardness and resistance to compression, making bone as strong as steel in resisting tension.
Functions of Bones
- Provide support for the body and its soft organs.
- Protect the central nervous system and vital organs.
- Facilitate movement through joint articulations and muscle attachment points.
- Serve as a mineral storage site for calcium and phosphorus.
- Produce blood cells, both red and white, in bone marrow.
- Store triglycerides for energy.
Bone Classifications
- The human skeleton consists of 206 named bones.
- Classified into two groups based on location: Axial and Appendicular.
- Axial skeleton includes bones along the body’s “long axis”: skull, vertebral column, and rib cage.
- Appendicular skeleton includes bones of the upper and lower limbs, attached to the axial skeleton by girdles.
Bone Shapes
- Long bones: longer than they are wide, like limb bones of the femur and humerus.
- Short bones: cube-shaped, found in the wrist and ankle, including sesamoid bones formed within tendons like the patella.
- Flat bones: thin, flat, slightly curved, such as the sternum, scapulae, ribs, and cranial bones.
- Irregular bones: complicated or unique shapes, like vertebrae.
Compact Bone Structure
- Dense outer layer on every bone, appearing smooth and solid.
- Consists of osteons, elongated cylinders parallel to the bone axis functioning as “weight-bearing pillars” made of collagenous lamellae rings.
- Includes canals and canaliculi containing vessels and nerves.
- Central (Haversian) canal: core of the osteon.
- Perforating (Volkmann’s) canals: perpendicular to the central canal.
Spongy Bone Structure
- Referred to as “honeycomb” of flat pieces of bone known as trabeculae.
- Spaces between trabeculae are filled with marrow.
- Act as cables on a suspension bridge to resist stress.
Bone Structure in Short, Irregular, and Flat Bones
- Thin plates of spongy bone covered by compact bone.
- Compact bone is sandwiched between the periosteum, the outer membrane, and the endosteum, the inner membrane.
- No defined marrow cavity in these bones.
Long Bone Structure
- Diaphysis: shaft along the axis of the bone, containing compact bone surrounding a medullary cavity filled with marrow.
- Yellow marrow found here, which can transform into red marrow.
- Red marrow present in infants contained here.
- Epiphyses: ends of long bones.
- Separated from the diaphysis by an epiphyseal line, formed from the ossified epiphyseal plate (growth plate) where longitudinal bone growth occurs.
- Contains compact bone exterior and spongy bone interior.
- Red marrow found in trabecular cavities of all infant bones and in the head of the femur and humerus for adults.
- Articular cartilage at the ends covers the joint surfaces.
Long Bone Membranes
- Periosteum: double-layered membrane covering the external surface.
- Serves as an anchor point for tendons and ligaments.
- Does not cover joint surfaces.
- Endosteum: delicate internal membrane covering the trabeculae of spongy bone.
Bone Markings
- Indicate sites for muscle, ligament, and tendon attachment on external surfaces.
- Highlight areas involved in joint formation or passageways for blood vessels and nerves.
- Classified into three types: projections, which are outward bulges, depressions, which are bowl-like cut-outs, and openings, which are holes or canals.
Bone Cells
- Osteogenic (osteoprogenitor) cells: mitotically active stem cells found in the periosteum and endosteum that differentiate into osteoblasts or bone-lining cells.
- Osteoblasts: bone-forming cells that secrete unmineralized bone matrix (osteoid) containing collagen and calcium-binding proteins, contributing to the bone’s tensile strength.
- Osteocytes: mature bone cells that no longer divide and maintain the bony matrix, responding to mechanical stimuli and communicating with osteoblasts and osteoclasts.
- Osteoclasts: bone resorption (breakdown) cells that secrete enzymes and protons (H+) to breakdown the matrix, converting calcium salts to soluble forms, and phagocytize demineralized matrix and dead osteocytes, transferring products to the bloodstream.
Bone Development
- Skeleton starts as cartilage.
- Ossification is the process of bone tissue formation where cartilage is replaced by bone, except where flexibility is required.
- Endochondral ossification occurs when bone replaces hyaline cartilage, beginning at the primary ossification center (center of the shaft), forming all bones inferior to the skull (except the clavicle).
- Bone grows “out” through this process.
Long Bone Growth
- Longitudinal growth of long bones occurs via interstitial growth of the epiphyseal plate.
- Bone thickness increases through appositional growth.
- Bone growth stops during adolescence (around 18 years for females/female assigned at birth and 21 years for males/male assigned at birth).
- Chondroblasts divide less often.
- The epiphyseal plate thins and is replaced by bone.
- Epiphyseal plate closure occurs, fusing the epiphysis and diaphysis together.
- Some facial bones continue to grow throughout life.
Epiphyseal Zones
- Resting (Quiescent) Zone: inactive cells.
- Proliferation (Growth) Zone: rapidly dividing cells.
- Hypertrophic Zone: cells enlarge.
- Calcification Zone: cells die and calcify.
- Ossification (Osteogenic) Zone: osteoblasts lay down new bone.
Bone Remodeling
- A continuous process involving both resorption, the breakdown of bone by osteoclasts, and deposition, the laying down of new bone by osteoblasts.
Wolff's Law
- States that "Bone grows or remodels in response to the demands placed upon it".
- Bone anatomy reflects the stresses it endures.
- Emphasizes the importance of weight-bearing exercises.
- Explains differences in bone structure due to:
- Handedness: the dominant side has thicker, stronger bone.
- Muscle activity: larger projections are found where heavy, active muscles attach.
- Fetal bones lack features due to limited stress.
Fractures
- Breaks in bone caused by trauma or bone weakening.
- Classified based upon:
- Position of bone ends after fracture: nondisplaced (ends in normal positions) and displaced (ends out of normal alignment).
- Completeness of break: complete (broken all the way through) and incomplete (not broken all the way through).
- Skin penetration: open (compound) or closed (simple).
Fracture Repair
- Four stages of repair:
- Hematoma formation (first few days): torn blood vessels hemorrhage, forming a massive blood clot (hematoma) causing swelling, pain, and inflammation.
- Fibrocartilaginous (soft) callus formation (2-3 weeks): fibroblasts secrete collagen bridging the break and connecting broken ends; bone reconstruction begins with cartilage matrix formation and osteoblast activity.
- Bony (hard) callus formation (4-16 weeks): soft callus is converted to a hard callus of spongy bone, which continues until a firm union is formed (about 2 months).
- Bone remodeling (6-12 months): excess material in the diaphysis exterior and medullary cavity is removed and compact bone is laid down, reconstructing shaft walls.
Osteomalacia & Osteoporosis
- Osteomalacia: bone softening in adults (rickets in children) resulting from vitamin D and/or calcium deficiency, causing pain on weight bearing and deformities in children.
- Osteoporosis: bone resorption exceeds bone deposition, leading to a decrease in bone mass despite normal bone matrix.
- Common in vertebrae and femur.
- Postmenopausal women are at greater risk, while men are largely protected by testosterone.
Skeletal Tissue Summary
- Bones are hardened cartilage.
- Ossification forms bone as osteogenic cells become osteoblasts, which lay down a matrix that grows and ossifies, either interstitially or appositionally.
- Bones are structurally classified as long, short, flat, or irregular, with compact bone exteriors and spongy bone interiors containing trabeculae.
- Bone growth and hardening depend on stress (Wolff’s Law).
- Osteoclasts resorb damaged bone, triggering osteoblasts involved in bone remodeling.
- Lack of stress or increased resorption leads to osteoporosis.
- Excessive stress can cause fractures, which are classified based on the extent of bone damage.
- Fracture repair is a multi-stage process lasting weeks or months.
Chemical Makeup of Bone
- Bone consists of organic and inorganic components
- Organic components include osteoprogenitor cells, osteoblasts, osteocytes, osteoclasts and osteoids
- Inorganic component is largely composed of mineral salts
- Mineral salts comprise 65% of bone mass
- Provides hardness and resistance to compression
- Bone is ½ as strong as steel against compression, as strong as steel resisting tension
Function of Bones
- Provides support for the body and soft organs
- Protects the central nervous system and vital organs
- Enables movement via joint articulations and serves as the origin and insertion points for muscles
- Stores minerals, primarily calcium and phosphorus
- Facilitates blood cell formation (red and white) in the bone marrow
- Stores triglycerides for energy
Bone Classifications
- There are 206 bones in the human skeleton
- Bones are classified into two groups based on location
- Axial skeleton
- Includes the skull, vertebral column, and rib cage
- Appendicular skeleton
- Consists of the bones of the upper and lower limbs
- Girdles attach limbs to the axial skeleton
- Axial skeleton
- Bones are classified based on their shape
- Long bones
- Longer than they are wide
- Found in the limbs, such as the femur and humerus
- Short bones
- Cube-shaped
- Found in the wrist and ankle
- Sesamoid bones form within tendons, like the patella
- Flat bones
- Thin, flat, and slightly curved
- Examples include the sternum, scapulae, ribs, and cranial bones
- Irregular bones
- Complex or “weird” shapes
- Examples include vertebrae
- Long bones
Bone Structure
- Compact bone
- Dense, outer layer of every bone
- Appears smooth and solid
- Consists of osteons
- Osteons are elongated cylinders running parallel to the bone axis
- "Weight-bearing pillars" composed of collagenous lamellae rings
- Contains canals and canaliculi for vessels and nerves
- Central (Haversian) canal: core of the osteon
- Perforating (Volkmann's) canals: perpendicular to the central canal
- Spongy bone
- "Honeycomb" of flat pieces of bone (trabeculae)
- Spaces between trabeculae are filled with marrow
- Acts like suspension bridge cables to resist stress
Bone Structure: Short, Irregular, and Flat Bones
- Thin plates of spongy bone covered by compact bone
- Compact bone is sandwiched between the periosteum and the endosteum
- Periosteum: outer membrane covering
- Endosteum: inner membrane covering
- No defined marrow cavity
Bone Structure : Long Bones
- Diaphysis: shaft along the axis of the bone
- Compact bone surrounds the medullary cavity filled with marrow
- Yellow Marrow found here
- Can convert to red bone marrow
- Red Marrow found in infants
- Compact bone surrounds the medullary cavity filled with marrow
- Epiphyses: ends of the long bones
- Separated from the diaphysis by the epiphyseal line
- Ossified epiphyseal plate (growth plate) where bone growth occurs
- Compact bone exterior, spongy bone interior
- Red Marrow found in trabecular cavities in all infant bones
- In the head of the femur and humerus for adults
- Articular cartilage at the ends covers the joint surfaces
- Separated from the diaphysis by the epiphyseal line
Bone Structure: Long Bones
- Long bones have two membranes
- Periosteum: double-layered membrane covering the external surface
- Anchor point for tendons and ligaments
- Does not cover joint surfaces
- Endosteum: delicate, internal membrane
- Covers trabeculae of spongy bone
- Periosteum: double-layered membrane covering the external surface
Bone Markings
- Sites of muscle, ligament, and tendon attachment on external surfaces
- Areas involved in joint formation or conduits for blood vessels and nerves
- 3 Types:
- Projections: outward bulges
- May be due to increased stress from muscle or a joint modification
- Depressions: bowl-like cut-outs
- Passage for vessels and nerves
- May play a role in joint formation
- Openings: holes/canals
- Passage for vessels and nerves
- Projections: outward bulges
Bone Cells
- Osteogenic (osteoprogenitor) cells
- Mitotically active stem cells
- Differentiate into osteoblasts or bone-lining cells
- Found in periosteum and endosteum
- Mitotically active stem cells
- Osteoblasts
- Bone-forming cells
- Secrete unmineralized bone matrix (osteoid)
- Made of collagen (90%) and calcium-binding proteins
- Contributes to bone's tensile strength
- Made of collagen (90%) and calcium-binding proteins
- Actively mitotic
- Osteocytes
- Mature bone cells (no longer divide)
- Maintain bony matrix
- Respond to mechanical stimuli (force/weight)
- Communicate information to osteoblasts and osteoclasts
- Osteoclasts
- Bone resorption (breakdown) cells
- Secrete enzymes and protons (H+) to break down the matrix
- Converts calcium salts to soluble forms
- Phagocytize demineralized matrix and dead osteocytes
- Products transferred to the bloodstream
- Bone resorption (breakdown) cells
Bone Development
- Skeleton starts out as cartilage
- Ossification: process of bone tissue formation
- Cartilage is replaced by bone everywhere except where flexibility is required
- Endochondral ossification:
- Bone replaces hyaline cartilage
- Begins at the primary ossification center (center of shaft)
- Bone grows "out"
- Forms all bones inferior to the skull (except the clavicle)
Long Bone Growth
- Long bones grow lengthwise via interstitial (longitudinal) growth of the epiphyseal plate
- Bones increase thickness via appositional growth
- Bones stop growing during adolescence (F/AFAB: ~18 yrs; M/AMAB: ~21 yrs)
- Chondroblasts divide less often
- Epiphyseal plate thins and is replaced by bone
- Epiphyseal plate closure: epiphysis and diaphysis fuse
- Some facial bones continue to grow throughout life
Epiphyseal Zones
- Resting (Quiescent) Zone: inactive cells
- Proliferation (Growth) Zone: rapidly dividing cells
- Hypertrophic Zone: cells enlarge
- Calcification Zone: cells die and calcify
- Ossification (Osteogenic Zone): osteoblasts lay down new bone
Bone Remodeling
- A continuous process of resorption and deposition
- Resorption: breakdown
- Osteoclasts will break down the matrix
- Deposition: laying down new bone
- Osteoblasts lay down new matrix
- Resorption: breakdown
Wolff's Law
- Trigger for remodeling is unknown. It may be related to Wolff's Law
- "Bone grows or remodels in response to the demands placed upon it"
- Bone anatomy reflects the stress the bone endures
- Importance of weight-bearing exercises
- Explains differences due to:
- Handedness: dominant side has thicker, stronger bone
- Larger projections found where heavy, active muscles attach
- Compare humerus to femur
- Weightlifter v non-weightlifter
- Fetal bones have no features due to the lack of stress on bone
Fractures
- Breaks in bone due to trauma or weakening in bone
- Classified based upon:
- Position of bone ends after fracture
- Nondisplaced: ends in normal positions
- Displaced: ends out of normal alignment
- Completeness of break
- Complete: broken all the way through
- Incomplete: not broken all the way through
- Skin Penetration
- Yes = Open (compound)
- No = Closed (simple)
- Position of bone ends after fracture
Fracture Repair
- 4 Stages:
- Hematoma (first few days)
- Torn blood vessels hemorrhage forming a massive blood clot (hematoma)
- Site swollen, painful, inflamed
- Fibrocartilaginous (Soft) Callus (2 – 3 wks)
- Fibroblasts secrete collagen
- Span break, connecting broken ends
- Bone reconstruction begins
- Cartilage matrix forms to repair tissue
- Osteoblasts form spongy bone within matrix
- Fibroblasts secrete collagen
- Bony (Hard) Callus (4 – 16 wks)
- Soft callus converted to a hard callus of spongy bone
- Continues for ~2 mos until a firm union forms
- Soft callus converted to a hard callus of spongy bone
- Bone Remodeling (6 – 12 mos)
- Excess material in the diaphysis exterior and medullary cavity is removed
- Compact bone is laid down reconstructing shaft walls
- Hematoma (first few days)
Osteomalacia & Osteoporosis
- Osteomalacia: bone softening (in adults)
- Rickets in children
- Caused by vitamin D and/or calcium deficiency
- Causes pain on weight bearing
- Will also lead to bowed legs and other deformities in children
- Osteoporosis: bone resorption exceeds bone deposition
- Bone matrix is normal, but bone mass declines
- Most common in vertebrae and femur
- Postmenopausal women are at the greatest risk
- Men largely protected by the effects of testosterone
Chemical Makeup of Bone
- Bone composition is both organic and inorganic
- Organic component consists of:
- Osteoprogenitors
- Osteoblasts
- Osteocytes
- Osteoclasts
- Osteoids
- Inorganic component primarily consists of:
- Mineral salts, mainly calcium phosphate
- Makes up 65% of bone mass
- Provides hardness and resistance to compression
- Strengthens bone to resist compression (as strong as steel) and tension (half as strong as steel)
Function of Bones
- Provides structural support for the body and soft organs
- Protects the central nervous system and vital organs
- Facilitates movement through joint articulation and muscle origin/insertion
- Serves as a mineral storage site for calcium and phosphorus
- Produces blood cells (red and white) in bone marrow
- Stores triglycerides for energy
Bone Classifications
- Human skeleton comprised of 206 total named bones
- Bones are grouped based on their location:
- Axial skeleton (skull, vertebral column, rib cage)
- Appendicular skeleton (bones of upper and lower limbs)
- Girdles attach limbs to the axial skeleton
- Bones are classified based upon their shape:
- Long bones: longer than they are wide (limb bones, femur & humerus)
- Short bones: cube-shaped (bones of wrist and ankle), Sesamoid bones form within tendons (patella)
- Flat bones: thin, flat, slightly curved (sternum, scapulae, ribs, cranial bones)
- Irregular bones: complicated or "weird" shapes (vertebrae)
Bone Structure
- Compact bone: dense outer layer present in all bones
- Appears smooth and solid
- Consists of osteons:
- Elongated cylinders parallel to bone axis
- "Weight-bearing pillars" made of collagenous lamellae rings
- Contains canals & canaliculi:
- Central (Haversian) canal: core of osteon
- Perforating (Volkmann’s) canals: perpendicular to the central canal and containing vessels & nerves
- Spongy bone: "honeycomb" of flat pieces of bone (trabeculae)
- Trabeculae are filled with marrow and act as cables on a suspension bridge to resist stress
Bone Structure of Short, Irregular, and Flat Bones
- Thin plates of spongy bone covered by compact bone
- Compact bone is sandwiched between:
- Periosteum: outer membrane covering the bone
- Endosteum: inner membrane covering the bone
- No defined marrow cavity
- Trabeculae of spongy bone
Bone Structure of Long Bones
- Diaphysis: shaft along the axis of the bone
- Compact bone surrounding the medullary cavity filled with marrow
- Yellow marrow found here and can convert to red bone marrow (in infants)
- Epiphyses: ends of long bones
- Separated from the diaphysis by the epiphyseal line (ossified epiphyseal plate)
- Contains articular cartilage covering the joint surfaces
- Articular cartilage at ends covering joint surfaces
- Compact bone surrounding the medullary cavity filled with marrow
Bone Membranes
- Long bones have two membranes:
- Periosteum: double-layered membrane covering the external surface
- Anchor point for tendons & ligaments
- Does not cover joint surfaces
- Endosteum: delicate internal membrane covering trabeculae of spongy bone
- Periosteum: double-layered membrane covering the external surface
Bone Markings
- Sites of muscle, ligament, and tendon attachment
- Areas involved in joint formation or conduits for blood vessels & nerves
- Types:
- Projections: outward bulges
- Depressions: bowl-like cutouts
- Openings: holes/canals
Bone Cells
- Osteogenic (osteoprogenitor) cells: mitotically active stem cells in periosteum & endosteum
- Differentiation into osteoblasts or bone-lining cells
- Osteoblasts: bone-forming cells secreting unmineralized bone matrix (osteoid)
- Made of collagen (90%) and calcium-binding proteins
- Contribute to bone's tensile strength
- Actively mitotic
- Made of collagen (90%) and calcium-binding proteins
- Osteocytes: mature bone cells (no longer divide)
- Maintain bony matrix
- Respond to mechanical stimuli
- Communicate information to osteoblasts & osteoclasts
- Osteoclasts: bone resorption (breakdown) cells
Bone Development
- Skeleton starts as just cartilage
- Ossification: process of bone tissue formation, where cartilage is replaced by bone
- Endochondral ossification: bone replaces hyaline cartilage
- Begins at primary ossification center (center of shaft)
- Forms all bones inferior to the skull (except clavicle)
Long Bone Growth
- Long bones grow in length via interstitial (longitudinal) growth of the epiphyseal plate
- Increase in thickness occurs via appositional growth
- Growth stops during adolescence (F/AFAB: ~18 yrs, M/AMAB: ~21 yrs)
- Chondroblasts divide less often
- Epiphyseal plate thins and is replaced by bone
- Epiphyseal plate closure: epiphysis & diaphysis fuse
- Some facial bones continue to grow throughout life
Epiphyseal Zones
- Resting (Quiescent) Zone: inactive cells
- Proliferation (Growth) Zone: rapidly dividing cells
- Hypertrophic Zone: cells enlarge
- Calcification Zone: cells die & calcify
- Ossification (Osteogenic) Zone: osteoblasts lay down new bone
Bone Remodeling
- Constant back and forth between resorption (breakdown) and deposition (laying down new bone)
- Resorption: Osteoclasts
- Secrete enzymes & protons (H+) to breakdown matrix
- Converts calcium salts to soluble forms
- Phagocytize demineralized matrix & dead osteocytes
- Products transferred to bloodstream
- Secrete enzymes & protons (H+) to breakdown matrix
- Deposition: Osteoblasts
- Resorption: Osteoclasts
Wolff’s Law
- Trigger for remodeling unknown, but may be related to Wolff’s Law: "Bone grows or remodels in response to the demands placed upon it"
- Bone anatomy reflects the stress it endures
- Importance of weight-bearing exercises
- Differences in bone due to:
- Handedness: dominant side has thicker, stronger bone
- Larger projections found where heavy, active muscles attach
- Humerus vs. Femur
- Weightlifter vs. Non-weightlifter
- Fetal bones have no features due to lack of stress
- Bone anatomy reflects the stress it endures
Fractures
- Breaks in bone due to trauma or bone weakening
- Classified based upon:
- Position of bone ends after fracture:
- Nondisplaced: ends in normal positions
- Displaced: ends out of normal alignment
- Completeness of break:
- Complete: broken all the way through
- Incomplete: not broken all the way through
- Skin penetration:
- Yes = Open (compound)
- No = Closed (simple)
- Position of bone ends after fracture:
Fracture Repair
- Four stages:
- Hematoma (first few days):
- Torn blood vessels hemorrhage forming a massive blood clot (hematoma)
- Site swollen, painful, inflamed
- Fibrocartilaginous (Soft) Callus (2–3 wks)
- Fibroblasts secrete collagen
- Span break connecting broken ends
- Bone reconstruction begins
- Cartilage matrix forms to repair tissue
- Osteoblasts form spongy bone within the matrix
- Fibroblasts secrete collagen
- Bony (Hard) Callus (4–16 wks)
- Soft callus converted to hard callus of spongy bone
- Continues for ~2 mos until firm union forms
- Soft callus converted to hard callus of spongy bone
- Bone Remodeling (6–12 mos)
- Excess material in diaphysis exterior & medullary cavity removed
- Compact bone laid down reconstructing shaft walls
- Hematoma (first few days):
Osteomalacia & Osteoporosis
- Osteomalacia: bone softening (in adults)
- Rickets in children
- Caused by vitamin D and/or calcium deficiency
- Causes pain on weight bearing
- Leads to bowed legs and other deformities in children
- Osteoporosis: bone resorption exceeds bone deposition
- Bone matrix is normal, but bone mass declines
- Most common in vertebrae & femur
- Postmenopausal women at greatest risk
- Men protected by effects of testosterone
Skeletal Tissue Summary
- Bones are hardened cartilage formed by osteogenic cells differentiating into osteoblasts
- Osteoblasts lay down a matrix that grows interstitially or appositionally and ossifies
- Classified based upon their structure:
- Long, short, flat, irregular
- Compact bone exteriors with spongy bone in the middle filled with trabeculae
- Bone growth and hardening depend on how they are stressed (Wolff’s Law)
- Osteoclasts resorb damaged bone stimulating osteoblasts to begin the bone remodeling process
- Bones not stressed or where resorption exceeds deposition fall victim to osteoporosis
- Bones which get overly stressed and fail (break) are fractured
- Fractures classified based upon how the bone has been damaged (ends still in-line? Bone completely broken? Does it pierce skin?)
- Fracture repair is a multi-stage process lasting months or up to a year to complete
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Description
This quiz explores the fundamental concepts of anatomy and physiology, including the structure of the body and its systems. Understand the relationship between various body parts and how they function together to maintain homeostasis. Test your knowledge on topics like the integumentary system and the principles of development throughout life.
