Anatomy Exam 1

• Six levels of organization:

  •Chemical - Atoms and molecules

  •Cellular - Cells

  •Tissue - Groups of similar cells

  •Organ - Contains two or more types of tissues

  •Organ System - Organs that work closely together

  •Organismal - All organ systems
• Homeostasis: Maintenance of relatively stable internal conditions despite continuous changes in environment

  A dynamic state of equilibrium
• Two systems are involved in Homeostasis: nervous and endocrine systems
• •Receptor (sensor): sense or feel internal environment, respond to stimuli/collects changes
• Control center

  Determines set point at which variable is maintained, Receives input from receptor, Determines appropriate response
• •Effector – Receives output from control center, a muscle or gland that responds to a stimulus either reduces (negative feedback) or enhances stimulus (positive feedback),
• Negative Feedback: Response reduces or shuts off original stimulus
• Positive Feedback: Response enhances or exaggerates original stimulus, ex: blood clots and contractions from labor
• Homeostatic Imbalance: imbalance/disturbance of homeostasis, diseases, ageing
• Anterior: front

  Posterior: back
• Directional Terms

  Superior: above

  Inferior: below
• Directional Terms

  Ventral: in front of

  Dorsal: behind
• Directional Terms:

  Medial: towards the inner/midline of the body

  Lateral: away from the midline of the body/outer
• Directional Terms

  Proximal: close to the trunk/point of attachment of a limb to the trunk

  
  

  Distal: farther from the trunk/point of attachment of a limb to the trunk

  
• Directional Terms

  Superficial: towards or at the body surface

  Deep: away from the body surface; more internal

  
• Body Planes and Sections

  sagittal: section divides the body (or organ) into left and right parts

  median: section divides the body (or organ) into equal left and right parts

  frontal: section divides the body (or organ) into anterior and posterior parts.

  transverse: or cross, section divides the body (or organ) into superior and inferior parts

  
• Body Cavities:

  •Dorsal body cavity:

  • Cranial cavity houses the brain
  • Spinal cavity houses the spinal cord
• Body Cavities:

  •Ventral body cavity:

  • Thoracic cavity houses heart, lungs, and others
  • Abdominopelvic cavity houses digestive system and most urinary system organs
• Membranes in Ventral Body Cavity:

  •Serous membrane or serosa: Thin, double-layered membranes, inside

  •Visceral: covers internal organs

  •Parietal: covers outer organs

  •Layers separated by slit-like cavity filled with serous fluid

  •Fluid secreted by both layers of membrane
• Serous Membranes:

  •Pericardium: Heart

  • parietalcardium: outer layer
  • pericardial: space contains liquid
  • visceral pericardium: inner layer

  •Pleurae: Lungs

  •Peritoneum: covers stomach/Abdominopelvic cavity

  
• Four basic tissue types: epithelial, connective, muscle, and nervous tissue
• •Epithelial tissue has five distinguishing characteristics:

  1. Polarity -2 poles
  2. Specialized contacts
  3. Supported by connective tissues
  4. Avascular, but innervated
  5. Regeneration
• Specialized contacts:

  –Epithelial tissues need to fit closely together

  –Specialized contact points bind adjacent epithelial cells together

  • Lateral contacts include:–Tight junctions, Desmosomes
• •Regeneration

  –Epithelial cells have high regenerative capacities

  -Stimulated by loss of apical-basal polarity and broken lateral contacts
• •Gland

  Endocrine: internally secreting, ductless (example: hormones)

  Exocrine: externally secreting products into ducts (example: sweat)
• Multicellular exocrine glands:

  –Mode of secretion:

  • Merocrine: most secrete products by exocytosis as secretions are produced (sweat, pancreas)
  • Holocrine: accumulate products within, then rupture (sebaceous oil glands)
  • Apocrine: accumulate products within, but only apex ruptures
• •Four main classes: Connective tissue proper, Cartilage, Bone, Blood
• •All connective tissues have three main elements: Ground substance, Fibers, Cells
• Connective Tissue Cells:

  Cells

  •“Blast” cells: Immature form of cell that actively secretes ground substance and ECM fibers

  ex: fibroblasts, chondroblasts, osteoblasts

  •“Cyte” cells: Mature, less active form of “blast” cell that now becomes part of and helps maintain health of matrix.

  ex: chrondrocytes,
• CT proper: dense connective tissues:

  •Elastic connective tissue:

  •Some ligaments are very elastic

  Example: ligaments connecting adjacent vertebrae must be very elastic

  •Also found in walls of many large arteries

  •Arteries need to stretch when blood enters and recoil to push blood out
• •Three types of membranes: Cutaneous membranes, Mucous membranes, Serous membranes
• The cutaneous membrane (the skin)

  covers the body surface.
• •Mucous membranes line body

  cavities that are open to the

  exterior.
• Serous Membrane/Serosae: line ventral body cavities that are closed to the exterior.

  •Special names given to show location: pleurae (lungs), pericardium (heart), peritoneum (abdomen)

  
• Epidermis consists of keratinized stratified squamous epithelium for protection
• Cells of Epidermis:

  • Keratinocytes- Keratin: gives extra protected shield, dead cells
  • Melanocytes- Melanin: protects apical surface of keratinocyte nucleus from UV damage
  • Dendritic- Macrophages: get rid of bad/foreign harmful stuff/key activators of immune system
  • Merkel Cells: sensory touch receptors
• Keratinocytes: synthesis of keratin, form a barrier against environmental damage

  •Produce fibrous keratin: protein that gives skin its protective properties
• Stratum corneum: layers of dead cells, filled with keratin, do not divide
• stratum granulosum: full of keratohyaline granules
• stratum basale: actively mitotic stem cells, contains melanocytes and dendritic cells, form new skin cells/divide