Anatomy is the study of the structure of an organism.
Physiology is the study of the functions of an organism; how it works.
Structural hierarchy:
 Cell>Tissue>Organ>Organ system>Organism
Tissue – a group of similar cells that perform a specific function
4 major tissue types: epithelial, connective, muscle, nervous

Epithelial tissue (epithelium) – occurs as sheets of tightly packed cells that cover body surfaces and line internal organs and cavities
Classification of epithelial tissue ... arrangement & shape; terms may be combined  
  arrangement 
    simple (one layer) 
    stratified (more than one layer) 
   shape 
    squamous (flat, scale-like) 
    cuboidal (as tall as they are wide) 
    columnar (tall and column-shaped) 
Mucous membrane – epithelial tissue lining our digestive & respiratory tracts that secretes mucous to keep it moist

Connective tissue is a sparse population of cells in an extracellular matrix.  The matrix is produced by the cells.
C.T. includes a variety of different tissue types: blood, bone, fat, etc.
Loose C.T. (the most common type) serves to bind and pack material; i.e. it holds organs in place.
Adipose tissue (fat) pads and insulates the body.  It also stores energy.
Blood consists of cells (red and white) in a fluid matrix (plasma).  It transports materials around the body.
Fibrous C.T. has a matrix of densely packed parallel bundles of collagen fibers.  It forms tendons that hold muscles to bones and ligaments that hold bones to bones. 
Cartilage forms a strong but flexible material with several functions related to the skeleton.  
Bone is a stiff matrix of collagen fibers in calcium salts.  

Muscle tissue consists of bundles of long muscle fibers.
Muscle tissue is the most common type of tissue in a vertebrates.
Skeletal muscle is attached to the skeleton (by tendons) and allows us to move.  
Cardiac muscle forms the heart.
Smooth muscle is found in the internal organs.  They move slower than skeletal muscle but have more endurance.

Nervous tissue forms a communications system to transmit nerve signals around the body.
The basic nerve cell is called a neuron.  
Nerve signals usually travel from one place to another by a chain of neurons, each passing the signal to the next one.

Organs consist of several tissues working together to accomplish a function.
Examples of organs are: heart, brain, stomach, skin, pancreas, spleen, etc.

The 11 basic body systems:
  Digestive – ingests food and breaks it down into smaller chemical units; consists of the oral cavity, esophagus, stomach, small & large intestines
  Respiratory – exchanges gases with the environment (takes in oxygen, releases carbon dioxide); consists of the nasal cavity, larynx, trachea, and lungs
  Circulatory – transports nutrients & oxygen to the body cells and takes wastes away for removal; consists of the heart, blood, blood vessels
  Lymphatic – helps circulate materials throughout the body; consists of lymph, lymph vessels, lymph nodes, spleen
  Excretory – filters wastes from the blood; consists of the kidneys, ureters, bladder, and urethra
  Endocrine – produces hormones to affect metabolic activities; consists of glands such as the pancreas, pituitary, thyroid, adrenal, etc.
  Reproductive – produces the sex cells and (in women) allows for the production of offspring; consists of ovaries or testes, uterus (in women)
  Nervous – coordinates body activities; consists of brain, spinal cord, nerves
  Muscular – allows us to move and perform certain body activities; consists of skeletal, cardiac, and smooth muscles
  Skeletal – provides support and protection; consists of bones, tendons, ligaments, cartilage
  Integumentary – protects the body; consists of skin, hair, nails, interior linings

New tools for viewing internal anatomy include:
Computed tomography (CT) – provides 360o X-rays of the body which are pieced together with a computer to give 3-D views 
Magnetic resonance imaging (MRI) – uses magnets to align hydrogen nuclei so that their radio signals can be picked up and converted to visual imagery

- Animals must exchange materials and heat with their environments.
- Small animals have enough surface to meet their needs, but larger animals need specialized structures to increase surface area.
- An interstitial fluid is used to exchange materials between blood and the body.
- As external conditions change, animals regulate their internal environment to maintain a steady state (homeostasis).
- Negative feedback is a system where the body senses when a certain level is reached and stops an action (i.e. an A/C thermostat)