BIOL 1106 Study Guide - Test 3

Study Guide: BIOL 1106 Test 3

Lesson 12

1. Comparison of Skeleton Types

  • Types of Skeletons:

    • Hydrostatic Skeleton: Found in soft-bodied organisms (e.g., earthworms); relies on fluid-filled compartments to provide shape and movement.

    • Exoskeleton: Hard outer structure (e.g., arthropods); provides support, protects internal organs, and serves as an area for muscle attachment.

    • Endoskeleton: Internal skeleton (e.g., humans); made of bone and cartilage, providing support and facilitating movement by anchoring muscles.

  • Movement: Different skeleton types influence how organisms move and how muscles are anchored.

2. Structure of Vascular Bone

  • Definition of Vascular Bone: A type of bone that contains blood vessels, allowing for nutrient transport.

  • Bone vs. Cartilage: Bone is rigid, contains calcium deposits, and has a vascular structure; cartilage is more flexible, lacks blood vessels, and provides cushioning.

  • Bone Cells:

    • Osteoblasts: Build bone tissue.

    • Osteocytes: Maintain bone matrix.

    • Osteoclasts: Resorb bone tissue.

3. Modes of Bone Development

  • Intramembranous Ossification: Bone develops directly from mesenchymal tissue.

  • Endochondral Ossification: Bone replaces hyaline cartilage; growth plates are crucial here for bone lengthening.

    • Growth Plates: Areas of active cell division leading to bone elongation.

4. Structure of Human Skeletal Muscle

  • Overview: Composed of muscle fibers which contain myofibrils, segmented into sarcomeres containing myofilaments (actin and myosin).

  • Muscle Cell Components:

    • Nuclei: Multiple nuclei per cell.

    • Sarcolemma: Membrane surrounding muscle fibers.

    • Mitochondria: Produce ATP for muscle contraction.

5. Sliding Filament Mechanism of Muscle Contraction

  • Initiation: Triggered by an action potential from a motor neuron.

  • Process:

    • Depolarization: Action potential causes sarcolemma depolarization and stimulation of T-tubules.

    • Shortening of Sarcomeres: Actin and myosin slide past each other, leading to muscle contraction.

    • Role of Calcium: Calcium is released from the sarcoplasmic reticulum, uncovering myosin binding sites for cross-bridge formation.

    • Cross-bridge Cycle: Involves attachment, pivoting, detachment, and re-cocking of myosin heads.

6. Nervous System Coordination of Muscle Contractions

  • Role of Motor Neurons: Transmit signals from the central nervous system (CNS) to skeletal muscle fibers.

  • Neuromuscular Junction: Acetylcholine is released, initiating muscle fiber depolarization.

  • Motor Unit Recruitment: CNS controls force and timing of muscle contractions by regulating the number of active muscle fibers.

7. Muscle Contractions Impacted by Fatigue and Fiber Type

  • Types of Muscle Fibers:

    • Slow-twitch (Type I): Higher endurance, more myoglobin (dark meat).

    • Fast-twitch (Type II): Lower endurance, designed for rapid bursts of activity (light meat).

    • Example: Leg muscles (predominantly slow-twitch) for endurance; breast muscles (predominantly fast-twitch) for short, powerful movements.

Lesson 13

1. Human Nutrition Requirements

  • Essential Nutrient Definition: Nutrients that must be obtained through diet as the body cannot synthesize them.

  • Example Essential Nutrients: Vitamins, certain amino acids, fatty acids.

  • BMR: Basal Metabolic Rate; the rate of energy expenditure per unit time at rest.

2. Structure and Function of the Digestive System

  • Path of Food: Mouth → esophagus → stomach → small intestine → large intestine.

  • Functions of Organs:

    • Mouth: Mechanical digestion and enzyme action.

    • Stomach: Acidic environment for digestion.

    • Small Intestine: Nutrient absorption.

    • Large Intestine: Water absorption and feces formation.

  • Organ Structure-Function Relationship: E.g., villi in the small intestine increase surface area for absorption.

3. Ingestion, Digestion, Absorption, and Elimination

  • Processes:

    • Ingestion: Intake of food.

    • Digestion: Breakdown of food into nutrients (mechanical and chemical).

    • Absorption: Uptake of nutrients into the bloodstream, primarily in the small intestine.

    • Elimination: Excretion of indigestible substances.

4. Major Digestive Enzymes

  • Sources of Enzymes: Produced by salivary glands, stomach, pancreas, and small intestine.

  • Active Locations: Each enzyme is activated in specific parts of the digestive system corresponding to the availability of substrates.

5. Accessory Organs

  • Accessory Organs Overview:

    • Pancreas: Produces digestive enzymes and bicarbonate.

    • Gallbladder: Stores bile produced by the liver.

    • Liver: Produces bile, detoxifies substances, and processes nutrients.

6. Variations in Vertebrate Digestive System

  • Carnivore vs. Herbivore: Each has adaptations based on diet; carnivores have shorter digestive tracts, while herbivores often have longer, more complex systems to break down cellulose.

7. Hormonal Regulation of Appetite and Body Weight

  • Key Hormones:

    • Leptin: Produced by adipose tissue; regulates energy balance and inhibits hunger.

    • Ghrelin: Produced by the stomach; stimulates appetite and promotes fat storage.
      Determining additional hormones would involve further complexity, which is less emphasized in this guide.