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Chapter 40

BIOL 1201 Chapter Notes - Chapter 40: Vasodilation, Vasoconstriction, Conformer

Biological Sciences
Course Code
BIOL 1201

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Bio 1202
Basic Principles of Animal Form and Function
Animal form and function are correlated at all levels of organization.
Physical laws, especially physics of exchanging materials with environment, limits range of animal forms.
Exchange in Simple Organisms (see fig. 40.3)
Single-celled organisms
- Exchange material by diffusion
- Entire plasma membrane is exposed to medium
Multicellular organisms with a sac body plan
- Body wall is only 2 cell-layers thick
- Exchange is by diffusion
Exchange in Complex Animals (see fig 40.4)
Large, complex animals have highly folded or branched internal surfaces
This increases surface area
Cell in these surfaces are specialized for exchanging materials
The basic scheme of organization involves cells organized into tissues organized into organs organized
into organ systems.
Composed of cells with similar structure and function
Non-cellular components made by the cells (i.e., bone and cartilage).
There are four general types of tissue (see 40.5):
>>>Epithelial tissue
Cells form continuous sheets called membranes
Membranes cover the body and line all body cavities
The main function of the epithelial tissue is to form a barrier and the cells are closely joined
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Because of this the epithelial tissue has no blood vessels
The tissues are either nourished by diffusion from capillaries beneath it or is continuously lost and
replaced by cell division
There are many types of epithelial tissue
>>>Connective tissue
Functions mainly to bind and support other tissues. Composed of sparsely packed cells scattered
throughout an extracellular matrix
Includes the layer beneath the skin called the Loose connective tissue, Fibrous connective
tissue, Cartilage, Bone, Adipose, Blood and Lymph.
The connective tissue is surrounded by large quantities of extracellular substances (between the living
cells) that are secreted from the connective tissue.
>>>Muscle tissue
Composed of long cells called muscle fibers capable of contracting in response to nerve signals. The
cells have actin and myosin fibrous proteins which are used for the contractive process.
There are three types of muscle
skeletal also called striated
>>>Nervous tissue
Sense stimuli and transmits signals throughout the animal. Composed of cells called neurons that are
specialized to generate and conduct electrical signals.
A neuron has four major parts:
Dendrites - receive signals
Cell body - maintains and repairs the cell
Axon - conducts electrical signal to target cell
Synaptic terminals - transmits the signal to target cell at a region called
the synapse
Organ Systems
Organ systems carry out the major body functions of most animals (see table 40.1):
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