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Animal form and function
- 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.
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Exchange with environment
- 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.
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Exchange with environment in larger animals
- 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.
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Tissue Structure and Function
Epithelial, Connective, Muscle and Nervous.
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Epithelial Tissue
- 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.
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Connective Tissue
- 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).
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Muscle Tissue
- 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.
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Nervous Tissue
- 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.
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Endocrine and Nervous system
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.
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Regulator vs Conformer
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.
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Negative vs Positive feedback
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.
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