Animal Organization & Homeostasis

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3Outline Tissue Types  Epithelial  Connective  Muscular  Nervous Organs Organ Systems Homeostasis  Negative Feedback  Positive Feedback

Animal Organization & Homeostasis 4 Levels of Organization Tissue - Group of similar cells performing a similar functionTissue - Group of similar cells performing a similar function Organ - Group of tissues performing a specialized functionOrgan - Group of tissues performing a specialized function Organ System - Collection of several organs functioning togetherOrgan System - Collection of several organs functioning together Organism - A collection of organ systemsOrganism - A collection of organ systems

Animal Organization & Homeostasis 5 Types of Tissues Four Major Types of Tissue 1.Epithelial tissue covers body surfaces and lines body cavities. 2.Connective tissue binds and supports body parts. 3.Muscular tissue causes body parts to move. 4.Nervous tissue responds to stimuli and transmits impulses.

Animal Organization & Homeostasis 6 Epithelial Tissue Epithelial tissue:  Forms a continuous layer over body surfaces  Lines inner cavities  Forms glands ­Exocrine glands - Secrete products into ducts or cavities ­Endocrine glands - Secrete products directly into the bloodstream  Covers abdominal organs

Animal Organization & Homeostasis 7 Epithelial Tissue Three types of epithelial tissues: 1.Squamous – Flat cells 2.Cuboidal - Cube-shaped cells 3.Columnar – Pillar-shaped cells Epithelial tissue forms a continuous layer over body surfaces including inner cavities.Epithelial tissue forms a continuous layer over body surfaces including inner cavities.

Animal Organization & Homeostasis 8 Epithelial Tissues Epithelial tissue forms a continuous layer over body surfaces including inner cavities.  Squamous epithelium is composed of flat cells (e.g., air sac linings of lungs, walls of capillaries).  Cuboidal epithelium has cube-shaped cells.  Columnar epithelium has elongated cells that resemble pillars or columns (e.g., small intestine).

Animal Organization & Homeostasis 9 Epithelial Tissues 1.Squamous epithelium is composed of flat cells (e.g., air sac linings of lungs, walls of capillaries).

Animal Organization & Homeostasis 10 Epithelial Tissues 2.Cuboidal epithelium has cube- shaped cells.

Animal Organization & Homeostasis 11  Columnar epithelium has elongated cells that resemble pillars or columns (e.g., small intestine). Epithelial Tissues

Animal Organization & Homeostasis 12 Epithelial Tissues Epithelium varies in number of cell layers.  Simple epithelium has one cell layer; all cells contact basement membrane.  Pseudostratified epithelium appears layered; actually, all cells contact basement membrane.  Stratified epithelium is composed of more than one layer of cells.

Animal Organization & Homeostasis 13 Figure 33.1d

Animal Organization & Homeostasis 14 Epithelial Tissues 1.Ciliated Epithelia - cells are covered with cilia (e.g., lining of human respiratory tract).  Cilia can bend and move material over the surface of the epithelium. 2.Glandular Epithelia - can be unicellular or have multicellular glands.  Glands are a single cell or a group of cells; they are classified in two types: ­Exocrine glands secrete their products into ducts or directly into a tube or cavity. ­Endocrine glands secrete their product directly into the bloodstream.

Animal Organization & Homeostasis 15 Connective Tissue Connective tissues consist of 3 components: 1.Specialized cells 2.Ground substance 3.Proteins fibers

Animal Organization & Homeostasis 16 Connective Tissue Connective tissues consist of:Connective tissues consist of: 1. Fibroblast cells 2. A matrix containing collagen and elastic fibers Loose fibrous connective tissueLoose fibrous connective tissue  Allows organs to expand Dense fibrous connective tissueDense fibrous connective tissue  Strong connective tissue ­Tendons ­Ligaments

17 Diagram of Fibrous Connective Tissue

Animal Organization & Homeostasis 18 Connective Tissue Adipose Tissue  Insulates the body and provides padding Cartilage  Classified according to type of collagen and elastic fibers found in the matrix  Cartilage cells (chondrocytes), lie in small chambers (lacunae) in the matrix

19 Connective Tissue Examples

20 Figure 33.3a

21 Figure 33.3c

22 Figure 33.3e Compact Bone Matrix is inorganic salts deposited around protein fibers Bone cells (osteocytes) are located in lacunae Lacunae arranged in concentric circles within osteons around tiny tubes (central canals)

23 Figure 33.4 Transports nutrients and oxygen to cells Removes carbon dioxide and other wastes Actually a connective tissue in which cells are embedded in a liquid matrix (plasma)  Red blood cells - erythrocytes  White blood cells - leukocytes

24 Blood, a Liquid Tissue

Animal Organization & Homeostasis 25 Muscular Tissue Contractile cells containing actin and myosin filaments Cells are called muscle fibers  Skeletal Muscle ­Voluntary - Long, striated fibers  Smooth Muscle ­Involuntary - No striations  Cardiac Muscle ­Striated, but mostly involuntary ­Bound by intercalated disks

Animal Organization & Homeostasis 26 Figure 33.5a

Animal Organization & Homeostasis 27

28 Muscular Tissue

Animal Organization & Homeostasis 29 Nervous Tissue Nervous Tissue contains neurons  Made up of dendrites, a cell body, and an axon ­Long axons covered by myelin ­Outside the brain and spinal cord, fibers form nerves  Neuroglia support and nourish neurons

Animal Organization & Homeostasis 30 Nervous Tissue Nervous system has three functions 1.Sensory input ­Sensory receptors detect changes ­Transmit info to the spinal cord 2.Data integration ­Spinal cord and brain integrate ­Decision is made regarding appropriate response 3.Motor output ­Response is transmitted to effector (gland or muscle) ­Effector initiates actual response

31 Neurons and Neuroglia Long axons and dendrites form neuron fibers; bound by connective tissue, they form nerves.

Animal Organization & Homeostasis 32 Nervous Tissue Nervous tissue is composed of NEURONS in the brain, spinal cord and nerves. Have three parts:  Dendrites receive a stimulus & conduct signals towards cell body.  Cell body contains most cytoplasm & nucleus of the neuron.  Axon conducts nerve impulses away from cell body.

Animal Organization & Homeostasis 33 Functions & Regions of Skin Functions of skin  Covers and protects underlying body regions  Regulate body temperature, and  Contains sensory receptor Epidermis - Outer, thinner region  Stratified squamous epithelium  New cells are pushed outward, become keratinized, and are sloughed off  Melanocytes produce melanin (pigment)  Nails grow from specialized epidermal cells

34 Human Skin Anatomy

Animal Organization & Homeostasis 35 Regions of Skin Dermis - Deeper and thicker than epidermis  Fibrous connective tissue containing elastic and collagen fibers Contains: ­Hair follicles ­Sebaceous glands ­Receptors ­Nerve fibers ­Blood vessels Subcutaneous Layer - Loose, connective tissue located below dermis

36 The Dermis & Epidermis

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Animal Organization & Homeostasis 38 Organ Systems Body Cavities  Dorsal cavity (toward the back) ­Contains the cranial cavity and the vertebral canal ­The brain is in the cranial cavity, and ­The spinal cord is in the vertebral canal  Ventral cavity (toward the front) is divided by the diaphragm into ­The thoracic cavity (includes heart and lungs) and ­The abdominal cavity (most other internal organs) ­The pelvic cavity

39 Mammalian Body Cavities

Animal Organization & Homeostasis 40Homeostasis The organ systems of the human body contribute to homeostasis  The digestive system ­Takes in and digests food ­Provides nutrient molecules that re- place used nutrients  The respiratory system ­Adds oxygen to the blood ­Removes carbon dioxide

Animal Organization & Homeostasis 41Homeostasis The organ systems of the human body contribute to homeostasis  The liver and the kidneys ­Store excess glucose as glycogen ­Later, glycogen is broken down to replace the glucose used ­The hormone insulin regulates glycogen storage  The kidneys ­Under hormonal control as they excrete wastes and salts

Animal Organization & Homeostasis 42 Negative Feedback Homeostatic Control  Partially controlled by hormones  Ultimately controlled by the nervous system Negative Feedback is the primary homeostatic mechanism that keeps a variable close to a set value  Sensor detects change in environment  Regulatory Center activates an effector  Effector reverses the changes

43 Negative Feedback Mechanisms: Simple

44 Negative Feedback Mechanisms: Complex

45 Regulation of Body Temperature

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Animal Organization & Homeostasis 47 Positive Feedback During positive feedback, an event increases the likelihood of another event  Childbirth Process  Urge to urinate Positive Feedback  Does not result in equilibrium  Does not occur as often as negative feedback

Animal Organization & Homeostasis 48Review Tissue Types  Epithelial  Connective  Muscular  Nervous Organs Organ Systems Homeostasis  Negative Feedback  Positive Feedback