Anatomy Directional Terms Quiz

Anatomical Directions

• Posterior (or dorsal) refers to the back or direction towards the back of the body
• Superior (or cranial) refers to a position above or higher than another part of the body
• Inferior (or caudal) refers to a position below or lower than another part of the body
• Lateral refers to the side or direction towards the side of the body
• Medial refers to the middle or direction towards the middle of the body
• Proximal refers to a position in a limb that is nearer to the point of attachment or the trunk of the body
• Distal refers to a position in a limb that is farther from the point of attachment or the trunk of the body
• Superficial refers to a position closer to the surface of the body
• Deep refers to a position farther from the surface of the body

Body Cavities

• Two major cavities: thoracic cavity and abdominal pelvic cavity
• Separated by the diaphragm
• Act to protect vital functions and allow organs to expand without disturbing other surrounding tissue

Cell Structure

• A cell can be divided into three main parts: plasma (cell) membrane, cytoplasm, and nucleus
• Organelles within the cytoplasm:
  • Membranous organelles: covered with their own plasma membrane, isolating them from the cytosol
  • Non-membranous organelles: no membrane, in direct contact with the cytosol
• Nucleus:
  • Contains genetic material (DNA)
  • Regulates cell activities
  • Surrounded by a double membrane (nuclear envelope)
  • Contains nucleolus, involved in ribosome synthesis
• Mitochondria:
  • Powerhouse of the cell
  • Site of cellular respiration
  • Generates ATP (adenosine triphosphate) energy
  • Has its own DNA (mitochondrial DNA)
• Endoplasmic Reticulum (ER):
  • Rough ER: studded with ribosomes, involved in protein synthesis and processing
  • Smooth ER: synthesizes lipids, detoxifies drugs and toxins
• Golgi Apparatus:
  • Modifies, sorts, and packages proteins and lipids
  • Forms vesicles for transport within the cell or secretion outside the cell
• Lysosomes:
  • Contain digestive enzymes
  • Break down cellular waste, foreign substances, and damaged organelles
  • Recycling center of the cell
• Ribosomes:
  • Site of protein synthesis
  • Can be free in the cytoplasm or bound to the rough ER

Cell Specialization

• Cells vary greatly in size and shape, with around 200 different types in the human body
• Cell signaling and recognition:
  • Integral proteins and carbohydrates on the cell surface are involved in cell signaling and recognition
  • Receptor proteins bind to specific signaling molecules, triggering cellular responses
• Cell surface carbohydrates participate in cell recognition and immune responses
• Cellular transport:
  • Integral proteins facilitate the transport of ions and molecules across the membrane
  • Channel proteins form pores for passive transport, allowing ions to move down their concentration gradient
  • Carrier proteins undergo conformational changes to transport specific molecules against their concentration gradient (active transport)
• Cell adhesion and support:
  • Membrane proteins and carbohydrates mediate cell-cell adhesion and interactions with the extracellular matrix
  • This adhesion is crucial for tissue formation, structural integrity, and stability of multicellular organisms

Membrane Transport

• Small, uncharged, lipid-soluble molecules can cross the lipid bilayer from ECF to ICF by simple diffusion
• Pinocytosis is a process where the cell sips up fluid and dissolved nutrients
• Phagocytosis is a process where the cell engulfs large particles or debris
• Tonicity:
  • Isotonic solutions have the same solute concentration as inside the cell
  • Hypertonic solutions have a higher concentration of solutes compared to inside the cell
  • Hypotonic solutions have a lower concentration of solutes compared to inside the cell

Body Systems

• 11 body systems and their functions:
  • Respiratory: breathing, lungs, trachea
  • Cardiovascular/Circulatory: blood circulation, heart, arteries, veins, blood
  • Digestive: processing food, mouth, pharynx, esophagus, stomach, intestines, accessory organs
  • Endocrine: hormone production, glands throughout the body
  • Urinary: waste elimination, kidneys, bladder
  • Reproductive: reproduction, uterus, ovaries, fallopian tubes
  • Nervous/Sensory: communication between and coordination of all body systems, nervous, brain, nerves, sensory
  • Integumentary: protects against damage, skin, hair, nails
  • Muscular/Skeletal: provides form, support, stability, and movement to the body, muscles, bones
  • Hematopoietic/Lymphatic: blood production, maintenance of fluid balance, and defense against disease, bone marrow, spleen, tonsils, lymph fluid, nodes, ducts, vessels

Cell Communication

• Direct communication: juxtacrine (near) gap junction, contains two connexons per gap junction, allows cell-to-cell communication, direct small molecule, ions, glucose, very fast, gap junction in heart, brain, and smooth muscles
• Five main types of indirect cell-to-cell communication

Epithelial Tissue

• Cellularity and tissue organization:
  • Epithelial tissues consist of closely packed cells with minimal extracellular matrix
  • Form continuous sheets that cover body surfaces, line cavities and organs, and create glands
• High mitotic activity: epithelial cells have a high rate of mitosis, allowing for rapid replacement and repair of damaged cells
• Interaction with environments: epithelium interacts with both internal and external environments, acts as a barrier, protects underlying tissues from mechanical damage, pathogens, and dehydration, and facilitates the exchange of nutrients and wastes between body compartments
• Basement membrane: separates the epithelium from underlying connective tissue, facilitates the exchange of substances between epithelial cells and blood vessels
• Specializations: epithelial cells exhibit various specializations to perform specific functions effectively, examples include cilia, which move substances along the cell surface, and microvilli, which increase surface area for absorption or secretion