Anatomy & Physiology Study Guide: Key Concepts and Systems

Introduction to Anatomy and Physiology

Definition of Anatomy and Physiology

Anatomy is the study of the structure of body parts and their relationships to one another. Physiology is the study of the function of the body’s structural machinery.

• Anatomy: Focuses on the physical structures (organs, tissues, cells).

• Physiology: Explores how those structures work and interact.

• Example: Studying the heart’s chambers (anatomy) and how it pumps blood (physiology).

Organ Systems of the Human Body

Overview and Functions

The human body is organized into several organ systems, each with specific functions vital for survival.

• Major Organ Systems: Integumentary, Skeletal, Muscular, Nervous, Endocrine, Cardiovascular, Lymphatic, Respiratory, Digestive, Urinary, Reproductive.

• Example: The digestive system breaks down food and absorbs nutrients.

• Additional info: Each system consists of organs working together to perform complex functions.

Genetic Information: Start and Stop Codons

Role in mRNA

Start and stop codons are sequences in mRNA that signal the beginning and end of protein synthesis.

• Start codon: Usually AUG, signals where translation begins.

• Stop codons: UAA, UAG, UGA, signal the end of translation.

• Example: The ribosome assembles at the start codon and releases the polypeptide at the stop codon.

Feedback Mechanisms

Positive and Negative Feedback

Feedback mechanisms regulate physiological processes to maintain homeostasis.

• Negative feedback: Reduces the effect of the stimulus (e.g., body temperature regulation).

• Positive feedback: Enhances the effect of the stimulus (e.g., blood clotting).

• Example: Insulin release lowers blood glucose (negative feedback).

Body Quadrants and Planes

Surface Quadrants

The abdomen is divided into four quadrants for anatomical reference: right upper, left upper, right lower, left lower.

• Quadrants: Used to locate pain, injuries, or organs.

• Example: The appendix is in the right lower quadrant.

Planes of the Body

Body planes are imaginary lines used to divide the body into sections.

• Sagittal plane: Divides body into left and right.

• Frontal (coronal) plane: Divides body into front and back.

• Transverse plane: Divides body into upper and lower parts.

Homeostasis

Concepts and Importance

Homeostasis is the maintenance of a stable internal environment despite external changes.

• Key components: Receptor, control center, effector.

• Example: Regulation of blood pressure.

Chemical Reactions in Physiology

Catabolism and Anabolism

Chemical reactions in the body are classified as catabolic (breaking down) or anabolic (building up).

• Catabolism: Breakdown of molecules to release energy.

• Anabolism: Synthesis of complex molecules from simpler ones.

• Example: Digestion is catabolic; protein synthesis is anabolic.

Cell Membrane and Transport

Functions and Characteristics

The cell membrane controls the movement of substances in and out of the cell and maintains cellular integrity.

• Plasma membrane: Selectively permeable barrier.

• Functions: Protection, communication, transport.

Transport Mechanisms

Molecules move across the cell membrane by various mechanisms:

• Osmosis: Movement of water across a membrane.

• Diffusion: Movement of molecules from high to low concentration.

• Facilitated diffusion: Movement via membrane proteins.

• Active transport: Movement against concentration gradient using energy.

• Endocytosis: Uptake of large particles via vesicles (clathrin-coated pits).

• Exocytosis: Release of substances from the cell.

Membrane Potential

Membrane potential is the electrical charge difference across the cell membrane, created by ions.

• Equation: $V_m = V_{inside} - V_{outside}$

• Example: Nerve impulse transmission.

Cellular Organelles

General Functions

Organelles are specialized structures within cells that perform distinct functions.

• Membrane-bound: Nucleus, mitochondria, endoplasmic reticulum.

• Non-membrane-bound: Ribosomes, cytoskeleton.

G-Protein Linked Second Messenger Systems

Location and Function

G-protein coupled receptors (GPCRs) are found in cell membranes and initiate second messenger cascades.

• Function: Transmit signals from outside to inside the cell.

• Example: cAMP pathway.

Body Cavities

Main Cavities and Their Contents

The body contains several major cavities that house organs.

• Pericardial cavity: Contains the heart.

• Pleural cavity: Contains the lungs.

• Peritoneal cavity: Contains abdominal organs.

Chemical Bonds

Types of Bonds Between Molecules

Molecules are held together by different types of chemical bonds.

• Ionic bond: Transfer of electrons between atoms.

• Covalent bond: Sharing of electrons between atoms.

• Hydrogen bond: Weak attraction between polar molecules.

Cell Division: Mitosis

Phases and Characteristics

Mitosis is the process by which cells divide to produce identical daughter cells.

• Prophase: Chromosomes condense, spindle forms.

• Metaphase: Chromosomes align at the cell equator.

• Anaphase: Sister chromatids separate.

• Telophase: Nuclear envelope reforms, chromosomes decondense.

Solutions: Tonicity

Types and Effects on Cells

Tonicity describes the effect of a solution on cell volume.

• Isotonic: No net movement of water; cell size remains constant.

• Hypertonic: Water moves out; cell shrinks.

• Hypotonic: Water moves in; cell swells.

Elements and Atomic Structure

Definition of an Element

An element is defined by the number of protons in its nucleus.

• Protons: Determine the atomic number and identity of the element.

• Electrons: Influence chemical behavior but do not define the element.

Water Properties

Surface Tension

Water molecules are attracted to each other, creating surface tension.

• Surface tension: The cohesive force at the surface of water.

• Example: Water droplets forming beads on a surface.

Carbohydrate Storage

Glycogen in the Liver

Carbohydrates are stored in the liver as glycogen, a polysaccharide.

• Glycogen: Branched polymer of glucose.

• Function: Energy storage.

Protein Structure

Levels and Characteristics

Proteins have four levels of structure, each with distinct characteristics.

Level	Characteristics
Primary	Sequence of amino acids
Secondary	Alpha helices and beta sheets (hydrogen bonding)
Tertiary	Three-dimensional folding (interactions among R groups)
Quaternary	Multiple polypeptide chains assembled

V-snares, T-snares, and Clathrin

Role in Cellular Transport

These proteins are involved in vesicle trafficking and membrane fusion.

• V-snares: Located on vesicles, help target vesicle to correct membrane.

• T-snares: Located on target membranes, facilitate fusion.

• Clathrin: Coats vesicles for endocytosis.

Summary Table: Key Terms and Functions

Term	Definition/Function
Homeostasis	Maintaining stable internal conditions
Osmosis	Water movement across membrane
Glycogen	Storage form of glucose in liver
Membrane Potential	Electrical charge difference across membrane
Surface Tension	Cohesive force at water surface