Biology
Chapter 20: Animal Structures and Functions
Lecture
Animal Structures (Anatomy) and Organ Systems (Physiology)
WebLecture Topics
Structures and Functions
We have been studying unicellular systems and plants so far. Now we are going to look at how animals are put together, and how the various metabolic functions are supported by specialized cells grouped into tissues, which associate with one another to form various organs. The study of structures in animals is anatomy, and a study of functions is physiology. While we make the distinction between the two areas of study, it is really impossible to talk about one without the other.
Check out the links for histology (cell study) slides and electron micrographs of the different types of cells as you have time Just click on the cell type (e.g., Epithelial), in the table below, then explore the audio slides so that you can listen to descriptions while looking at the example tissue type.
Tissues
| Type | Notes | Types of cells | Arrangements | Found in |
|---|---|---|---|---|
Filter layer: everything that enters or leaves the body crosses epithelial tissues Wear out and are replaced |
Squamous, columnar, cuboidal, goblet (secretes mucus), transitional |
Simple, stratified, pseudo-stratified. Epithelial membrane: lines external openings with mucous Serous membrane: lines enclosed areas |
Surfaces: skin and linings of tracts |
|
Few cells embedded in collagen fibers scattered in matrix. |
Collagen, reticular, elastic fibers fibroblasts macrophages chondrocytes (cartilage) |
Loose: fibers running throughout the body storing fluid/salts Dense: Collagen bundles providing support Elastic: lung tissue Reticular: provides support Adipose: fat storage Cartilage: non-vascular supportive, but elastic Bone: Supportive skeletal tissue, vascular, inflexible Blood, lymph: individual specialized cells suspend in plasma |
Cartilage, bone, blood and lymph |
|
Contains the proteins myosin and actin in long, thin contractile fibers called myofibrils |
Fiber cells: smooth skeletal cardiac |
Smooth: walls of tracts, consist of spindle-shaped fibers Skeletal: muscle masses consisting of long (2-3 cm) fibers with multiple nuclei Cardiac: heart muscle: networks of fibers; 1-2 nuclei per fiber cell |
Stomach, arm muscle, heart |
|
Store or transmit information, communicate at synapses; dendrites receive/axons transmit |
neurons glial cells |
Nerve: muerons bound together by connective tissue |
Spinal column, brain |
Organ systems
For an interactive view major body systems, check out the information at Human Anatomy On-line (this will run applets on your system; there are also some neat animations, so open this link in a separate window). This site divides the body into ten systems, rather than the twelve mentioned in your text.
You should be able to fill out this table on your own!
| System | (Typical) Components | Functions |
|---|---|---|
| Integumentary | Skin | Protective covering |
| Skeletal | Bones | Support, movement |
| Muscular | Muscles | Movement |
| Digestive | Mouth, stomach | Ingest/digest food |
| Circulatory (cardiovascular) | Heart, blood vessels | Transport materials |
| Respiratory | Lungs | Gas exchange |
| Urinary (excretory) | Kidney, bladder | Excretion |
| Nervous | Nerves, sense organs, brain | Receive and process stimuli |
| Endocrine | Ductless glands | Regulate blood chemistry, growth, development |
| Reproductive | Testes, ovaries | Kids |
| Lymphatic | Fluids, glands | Returns blood to circulatory system |
| Immune system | Glands, blood cells | Attacks invading substances |
Homeostasis
Almost all body organ systems contribute to maintaining a balance of chemical and thermal factors so that the metabolic functions of the body can be efficiently carried out. An excess of a particular hormone will trigger the organs which manufacture that chemical to stop supplying it, at least until the levels drop enough. A swing in body temperature, heart beat, or nervous response will be counteracted by some response or negative feedback in the body to return the temperature, beat rate, or response level to normal.
Animals regulate their internal temperatures to maximize metabolic processes. Ectotherms (cold-blooded animals) get their heat from their environment as well as from the exothermic metabolic processes within their bodies; their body temperatures fluctuate with their surroundings. Reptiles will bask in the sun, and many insects must utilize sun and shade areas to achieve body temperatures in acceptable ranges. Endotherms (warm-blooded animals, which includes mammals), retain a constant body temperature despite their surroundings. They need to use various mechanisms (increased movement, shivering, sweating) to control body temperature in response to heat or cold in the environment.
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