Anatomy and Physiology Chapter 2

Anatomy and Physiology Overview

• Anatomy involves the study of body structures, divided into gross (visible) and microscopic (cellular) categories.
• Key subcategories: regional anatomy, systemic anatomy, histology, and cytology.
• Physiology is the study of body functions and how anatomical structures work together.

Structure and Function Relationship

• Structure determines function; changes in protein shape can alter their functionality.
• Evolution of the human pelvis supports abdominal and thoracic organs effectively.
• Branching structures in organisms, such as respiratory tubes, enhance surface area for absorption and gas exchange.

Imaging Techniques

• Various imaging techniques are used to study anatomy:
  • Functional MRI (fMRI) and ultrasound visualize brain functions.
  • X-rays reveal hard structures like bones.
  • CT scans visualize soft tissues in greater detail.

Variations in Anatomy and Physiology

• Anatomical variation is common and does not usually affect function (e.g., varying numbers of pulmonary veins).
• Physiological variation is more prevalent and can be influenced by age and gender, affecting organ and system functionality.

Homeostasis

• Homeostasis maintains a stable internal environment by monitoring key parameters—pH, temperature, blood pressure, and electrolyte levels.
• Receptors collect data, which is processed by a control center to make necessary adjustments through effectors (e.g., sweating to regulate body temperature).

Flow and Gradients

• Flow refers to the movement of substances, governed by gradients (e.g., concentration, pressure).
• Higher gradients promote increased flow, while resistance opposes it.

Feedback Loops

• Negative feedback loops control various bodily functions, reducing the effect of an initial stimulus (e.g., blood sugar regulation).
• Positive feedback amplifies responses, exemplified by oxytocin release during childbirth that strengthens uterine contractions.

Organ Systems

• Body comprises multiple organ systems, each with specific functions:
  • Integumentary System: Protects against pathogens, sensory reception.
  • Skeletal System: Provides structure and protection.
  • Muscular System: Facilitates movement and temperature regulation.
  • Nervous System: Maintains homeostasis through sensory input.
  • Endocrine System: Regulates bodily functions via hormones.
  • Cardiovascular System: Transports essential substances throughout the body.
  • Digestive System: Breaks down food and absorbs nutrients.
  • Urinary System: Maintains blood pressure and pH, removes waste.
  • Reproductive System: Produces and exchanges gametes, supports fetal development.

Anatomical Position

• Standard position for human anatomy studies: standing upright, feet parallel, toes pointed forward, arms at the sides with palms facing forward.### Lymphatic System
• Regulates fluid balance within the body.
• Houses immune cells that defend against pathogens.

Respiratory System

• Facilitates the exchange of air with the atmosphere.
• Provides a surface area for oxygen and carbon dioxide diffusion into the blood.

Directional Terms and Anatomical Planes

• Sagittal Plane: Divides the body into right and left halves; midsagittal passes through the midline, while parasagittal is offset.
• Frontal (Coronal) Plane: Divides the body into front and back.
• Transverse Plane: Divides the body into top and bottom sections.
• Medial: Toward the midline.
• Lateral: Away from the midline.
• Superior: Above another structure.
• Inferior: Below another structure.
• Proximal: Closer to the origin of a body part.
• Distal: Farther from the origin of a body part.
• Cranial: Pertaining to the skull.
• Caudal: Toward the tail or lower part of the body.
• Anterior: Front of the body.
• Posterior: Back of the body.

Body Cavities and Organ Organization

• Posterior (Dorsal) Body Cavity: Includes cranial cavity (houses the brain) and spinal cavity (houses the spinal cord).
• Anterior Body Cavity: Contains thoracic cavity (includes pleural, mediastinum, and pericardial cavities) and abdominopelvic cavity (subdivided into abdominal and pelvic cavities).
• Serous Membranes: Two layers (parietal and visceral) that protect organs in the anterior body cavity, reducing friction during movement.

Abdominopelvic Quadrants

• Right Upper Quadrant (RUQ): Liver, gallbladder, right kidney, portions of stomach, small & large intestine.
• Left Upper Quadrant (LUQ): Left lobe of liver, stomach, pancreas, left kidney, spleen, portions of large intestine.
• Right Lower Quadrant (RLQ): Cecum, appendix, parts of small intestine, reproductive organs.
• Left Lower Quadrant (LLQ): Most of small intestine, parts of large intestine, reproductive organs.

Medical Imaging Techniques

• X-Rays: Useful for viewing bones and teeth; provides an internal view of the body to aid diagnosis.
• Computed Tomography (CT): Combines x-ray and computer technology for detailed imaging of internal structures.
• Magnetic Resonance Imaging (MRI): Uses radio signals for precise internal imaging; more costly than other imaging techniques.
• Positron Emission Tomography (PET): Detects metabolic activity to diagnose conditions like cancer and heart disease.
• Ultrasonography: Employs sound waves for real-time imaging, commonly used during pregnancy.

Chemical Level of Organization

• Matter: Anything that occupies space and has mass. Mass does not equal weight; mass remains constant regardless of gravity.
• Elements: Pure substances made of one type of atom; organized in the periodic table by atomic number and weight.
• Atoms and Molecules: Atoms are the smallest units of elements. Molecules are two or more atoms chemically bound.
• Isotopes: Variants of an element differing in the number of neutrons; protons remain constant.

Electron Behavior and Chemical Bonds

• Electron Shells: Regions around an atom's nucleus that contain electrons; the first can hold 2, the second up to 8.
• Cation: Positively charged ion; Anion: Negatively charged ion.
• Valence Shell: Outermost shell where atoms seek to fill their electron count by sharing, accepting, or donating electrons.

Cellular Structure and Function

• Organelles: Membrane-bound structures with specific functions such as the endoplasmic reticulum (ER), Golgi apparatus, lysosomes, and mitochondria.
• Endoplasmic Reticulum: Rough ER synthesizes proteins; Smooth ER is involved in lipid synthesis.
• Golgi Apparatus: Modifies and sorts products from the rough ER for transport.
• Mitochondria: The powerhouse of the cell; responsible for ATP production through aerobic respiration.

Cell Membrane Transport Mechanisms

• Endocytosis: Process by which cells internalize substances, including:
  • Phagocytosis: Engulfing large particles.
  • Pinocytosis: Cell drinking of fluids and solutes.
  • Receptor-Mediated Endocytosis: Specific molecules are brought into the cell via ligand-receptor interactions.
• Exocytosis: The process of exporting materials from the cell, such as hormones and enzymes.

Cytoskeleton Structure

• Microtubules: Composed of tubulin; provides structural support.
• Intermediate Filaments: Made of keratin; helps maintain cell integrity.
• Microfilaments: Composed of actin; involved in cell movement and shape.

Cell Surface Specializations

• Microvilli: Increase surface area for absorption.
• Cilia: Aid in movement across the cell surface.
• Flagella: Long, whip-like structures used for cell movement.

Prepare for your preliminary exam with this quiz on Chapter 2: Introduction to the Human Body. Explore the themes of anatomy and physiology, focusing on the crucial relationship between structure and function. Understand how changes in protein shape can influence biological functions.