Biology

• An animal's size and shape are fundamental aspects of form that significantly affect the way an animal interacts with its environment.
• Physical laws limit the range of animal forms.

• Exchange occurs as substances dissolve in an aqueous medium move across the plasma membrane of each cell.
• The amount of material that must be exchanged to sustain life is proportional to volume.
• Every cell need to have access to a suitable aqueous environment, either inside or outside of the animal's body.

• Every cell must be bathed in fluid and have access to oxygen, nutrients and other resources.
• The surfaces of exchange lie within the body, protecting delicate exchange tissues from abrasion of dehydratation and allowing for streamlined body contours.
• Intestitial Fluid: the fluid filling the spaces between cells in an animal.
• Exchange between intestitial fluid and circulatory fluid enables cells to obtain nutrients and get rid of wastes.

Epithelial, Connective, Muscle and Nervous.

• Covers the outside of the body and lines organs and cavities within the body.
• Epithelial cell shape: cuboidal (dice), columnar (bricks), or squamous (floor tiles).
• Arranged in: simple epithelium (single layer), stratified epithelium (multiple tier of cells), or pseudostratified epithelium (single layer varying in height).
• Cuboidal epithelium: kidney tubules, glands like thyroid and salivary.
• Simple columnar epithelium: intestines.
• Pseudostratified ciliated columnar epithelium: respiratory tract.
• Stratified squamous epithelium: skin, esophagus, anus, vagina.
• Simple squamous epithelium: blood vessels, lungs.

• Bind and support other tissues and hold organs together in the body.
• Types: loose connective tissue, cartilage, fibrous connective tissue, adipose tissue, blood, bone.
• Types of connective tissue: collagenous (provide strength and flexibility), elastic (easily stretched but resilent), reticular (joins tissues together).
• Contains Fibroblast (secrete protein for fibers) and Macrophages (engulf foreign particules and derbis).

• Resposible for all types of body movement.
• Types:skeletal, cardiac, and smooth.
• Skeletal muscle:for voluntary movements, longs cells called muscle fibers.
• Cardiac muscle:forms the contractile wall of heart, involuntary movement.
• Smooth muscle:in digestive tract, urinary bladder, arteries and internal organs, involuntary movement.

• The function is to sense stimuli and transmit signals in the form of nerve impulses.
• Contains neurons that transfer nerve impulses, glial cells that help nourish, insulate and replenish neurons.

Endocrine system: releases signaling molecules (hormones) into the bloodstream by endocrine cells that reach all locations in the body. Hormones may have an effect in a single location or in sites throughout the body. Hormones are slow acting but the effects are long-lasting. Good for gradual changes like growth and development, reproduction, metabolic processes and digestion.

Nervous system: each signal (nerve impulse) travels to a target cell along axons. Only neurons, muscle cells, endocrine cells and exocrine cells can receive signal. They can only travel thought a pathway. Transmition is very fast and last only a fraction of a second. Good for direct immediate and rapid responses to environment like movement and behavior.

Regulator: uses internal control mechanisms to regulate internal change in the face of external fluctuation (river otter). Temperature of regulator is independet of the environment.

Conformer: it allows its internal condition to conform to external changes in the variable (largemouth bass). As the water warms or cools, so do the cells in the conformer.

Negative feedback: a response the reduces the stimulus like sweating when you are producing heat by exercise, sweat cools the body.

Positive feedback: triggers mechanisms that amplify rather than diminish the stimulus. During child birth, the mother's uterus stimulates the uterus to contract that causes greater pression until the baby is born.