Download Ch 22-23

Chapter 22
Being Organized and Steady
Chapter 23
The Transport Systems
22.1 The Body’s Organization
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Tissue—group of similar cells performing a similar function
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Organ—contains different types of tissues each performing a function to aid in the overall action
of the organ
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Organ system
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Organism
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4 major tissue types
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Epithelial tissue (epithelium) covers the body surfaces and lines body cavities.
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Connective tissue binds and supports body parts.
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Muscular tissue moves the body and its parts.
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Nervous tissue receives stimuli and conducts nerve impulses.
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Epithelial tissue protects
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Also called epithelium
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Forms external and internal linings of many organs
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Covers the surface of the body
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Epithelial cells adhere to one another but are generally only 1 cell layer thick.
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Protective function—substances have to physically pass through epithelial cells to enter
the body
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Differentiated by shape
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Only type not subdivided into more types
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Squamous—flattened cells
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Cuboidal—cube-shaped cells
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Columnar—rectangular pillar or columns
One or more epithelial cells are the primary components of glands (produce and secrete
products)
Epidermis—outer region of skin
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Stratified (layered)
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Cell reinforced with keratin for strength and waterproofing
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Protection from injury, drying out, and pathogen invasion
Epithelial tissue constantly replaces its cells
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Useful in harsh environments like skin or digestive tract
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Also more likely to become cancerous
Connective tissue connects and supports
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All types involved in binding organs together and providing support and protection
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Connective tissue cells widely separated by matrix—noncellular material that varies
from solid to liquid
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Matrix usually has fibers—notably collagen
Types of connective tissue
1. Loose fibrous connective tissue
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Occurs beneath an epithelium
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Connects epithelium to other tissues within an organ
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Forms a protective covering for many internal organs
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Cells are fibroblasts—produce a matrix with collagen fibers and elastic fibers
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Adipose tissue—type of loose connective tissue
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Fibroblasts enlarge and store fat
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Limited matrix
2. Dense fibrous connective tissue
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More collagen fibers packed closer together than loose fibrous connective tissue
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More specific function—found in tendons (connect muscle to bone) and ligaments
(connect bones to bones at joints)
3. Cartilage and Bone
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Cartilage—cells lie in lacunae separated by solid yet flexible matrix
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Hyaline cartilage (most common type)—nose, ends of bone, fetal skeleton
Bone—most rigid connective tissue
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Hard matrix of inorganic salts (calcium) deposited around collagen fibers
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Rigidity with elasticity and strength
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Most common type is compact bone
4. Blood
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Composed of several types of cells suspended in liquid matrix (plasma)
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Blood unlike other connective tissue in that matrix (plasma) is not made by cells
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Transports nutrients and oxygen to cells; removes their wastes
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Helps distribute heat
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Plays role in fluid, ion, and pH balance
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Components help to fight disease and clot blood
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Red blood cells transport oxygen
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White blood cells fight infection
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Platelets, cell fragments, form a plug and release molecules to help clotting process
Muscular tissue moves the body
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Works with nervous tissue to enable movement
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Contains the contractile proteins actin and myosin
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3 types of vertebrate muscles
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Skeletal
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Cardiac
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Smooth
Nervous tissue communicates
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Coordinates body parts and allows an animal to respond to external and internal
environments
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Depends on
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Sensory input
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Integration of data
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Motor output to carry out functions
Neuron—nerve cell
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3 parts—dendrites, cell body, and axon
Neuroglia—cells that support and nourish neurons
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Outnumber neurons 9 to 1
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Schwann cells encircle axons forming myelin sheath that allows nerve impulses
to travel more quickly
22.2 Organs and Organ Systems
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Divide systems of the body into 5 groups
1. Transport of fluids throughout the body
2. Maintenance of the body
3. Control of the body’s systems
4. Sensory input and motor output
5. Reproduction
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All systems have functions that contribute to homeostasis—relative constancy of the internal
environment
22.3 Homeostasis
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Internal environment is the environment of the cells, tissues, fluids, and organs
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Tissue fluid surrounds cells
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Tissue fluid is constantly renewed by exchanges with blood
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Blood and tissue fluid are the internal environment of the body
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Homeostasis—maintenance of the relatively constant conditions of the internal environment
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Even though external conditions vary—internal conditions stay within a narrow range
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All body systems contribute to homeostasis.
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Negative feedback
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Primary homeostatic mechanism
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2 components
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Sensor—detects changes in the internal environment (stimulus)
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Control center—initiates an effect that brings conditions back to normal
Example
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Pancreas detects blood sugar too high
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Pancreas secretes hormone insulin that causes cells to take up glucose
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Blood sugar levels return to normal
23.1 Open and Closed
Circulatory Systems
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Most animals have a circulatory system to deliver oxygen and nutrients to cells and to take
carbon dioxide and wastes away from cells.
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Diffusion alone is sufficient for some organisms.
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More complex animals have a circulatory system in which a pumping heart moves fluid through
vessels.
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Open circulatory systems
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Grasshoppers have a tubular heart that pumps hemolymph (combination of blood and
tissue fluid)
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Pumped through channels and cavities containing the organs (hemocoel)
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Hemolymph sucked into openings in heart wall (ostia) and then ejected
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Hemolymph colorless—no hemoglobin
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Trachea are air tubes that bring in oxygen and take away carbon dioxide
Closed circulatory system
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Cardiovascular system consists of strong muscular heart and blood vessels
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Blood is always contained within vessels and normally never runs freely through the
body cavity
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3 types of vessels—arteries, veins, and capillaries
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Lymphatic system will pick up excess tissue fluid and return it to blood
The pulmonary and systemic circuits
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Pulmonary circuit
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O2-poor blood collected from body goes into right atrium
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Then right ventricle to the lungs via pulmonary trunk and pulmonary arteries
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Picks up O2, gives off CO2, and goes back to heart via pulmonary vein
Systemic circuit
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Pulmonary veins bring O2-rich blood to left atrium
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Then left ventricle to body via aorta
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Picks up CO2, gives off O2, and goes back to heart via venae cavae
Portal system
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Begins and ends in capillaries
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Hepatic portal takes blood from capillary bed in intestines to capillary bed in
liver then to veins entering inferior vena cava
Lymphatic system
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Consists of lymphatic vessels and organs
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Vessels take up excess tissue fluid and return it to blood
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Also take up fat in digestive tract
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Also part of immune system
Lymphatic vessels are extensive