Unformatted text preview: Chapter 41 ANIMAL FORM AND FUNCTION
Tissues and Homeostasis
pp. 937940 and 945946
*Organization of Living Things
Form (Structure) and Function
*Anatomy – physical structure
*Physiology – function.
*Evolution by natural selection based on changes in structure that allow organisms to function in their environment.
* Chemicals – * Cells * Tissues * Organ * Organ system * Organism *4 basic types
* Epithelial * Connective * Muscle * Nervous *Functions: Organization of Living Organisms Tissues Epithelial Tissue ***Regenerates quickly
*2 types: simple and stratified (layered)
*Epithelial tissue is polarized = 2 surfaces are different, fig 41.6.
* Apical surface faces the environment * Basolateral surface is attached to other tissues. *Simple epithelium
* Squamous: Epithelial Tissue * Cuboidal: * Columnar: *Stratified
* Squamous: tough outer layer of keratinized cells; skin, etc. * Pseudostratified: ciliated cells that line the respiratory tract and glands. *Goblet cells Connective Tissue *Functions:
*Packages and cushions organs
*Matrix = ground substance with fibers (elastin, collagen, reticular) and cells. *3 types: proper, cartilage and special.
*Connective Tissue Proper
* Loose connective tissue – insulates, supports, nourishes and protects epithelial tissues.
* Dense connective tissue – forms tendons, ligaments and capsules for organs. * Adipose (fat) – fuel storage, cushioning, insulation. * Cartilage – firm but flexible ground substance, chondrocytes (cells) in lacunae (spaces). Found in: 2 *Larynx
*Bone surfaces at joints ■Nose and ear *Special Bone *Functions: *Support
*Levers for skeletal muscles
*Blood cell production
*Storage of Ca and PO4. *Structure
*Organic matrix with collagen and rigid crystals of CaPO4. *Constantly remodeled by osteoclasts (tear down) and osteoblasts (rebuild). Mature cells are osteocytes that live in lacunae. *2 types: compact and spongy
* Spongy – open lattice containing marrow for blood cell production or fat storage.
* Compact – outer layer provides strength. Concentric rings (lamellae) laid down around a central canal = Haversian Canal. Nerves and blood vessles travel through this canal and nourish osteocytes. Connective Tissue *Special – Blood
*Functions: transport of materials
*Plasma – fluid part of blood containing proteins, lipids, ions, nutrients, CO2, etc.
* Erythrocytes * Leukocytes 3 * Platelets Muscle Tissue *Function: movement
*Structure: specialized cells that have highly organized contractile filaments, actin and myosin. *3 types:
* Smooth muscle * Skeletal muscle * Cardiac muscle Nervous Tissue
*Function: generates and transmits electrical impulses
* Neurons = nerve cells * Neuroglia = supporting cells *Neuron Structure
* Dendrites * Axon * Myelin sheath *Types of Neurons: * Sensory peripheral nervous system. * Motor – central nervous system 4 * Interneurons central nervous system. * Nerves are bundles of axons with blood vessels and ganglia are collections of nerve cell bodies.
Homeostasis *Means –same or like standing.
*In living things, it means the maintenance of internal chemical and physical conditions relatively constant despite changes in the environment.
*2 ways to cope with the environment:
* Conformational – adapting to environmental conditions, ex. ectothermic animals
* Regulatory – active physiological processes that correct problems, ex. endothermic animals.
*Regulatory processes – negative feedback loops, fig 41.14 and 41.16.
*Internal conditions have a normal value or range of values = set point. Variations from the set point stimulate a …
* Sensor that relays this information to an… * Integration center that evaluates the information and sends instructions, if necessary, to an…
* Effector that corrects the problem and eliminates the signal to the sensor. *Regulatory systems positive feedback loops
*Used sparingly in living things.
*Stimulus – integrations center effector. In this case the effector does not eliminate the stimulus to the sensor and the physiological mechanism is amplified. Ex. Blood clotting, labor. 5 ...
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