Homeostasis and the Organization of the Body Chapter 32

Homeostasis State of balance within the body Maintaining body conditions within set limits

Regulating body temperature Endotherms (“inside heat”) Produce heat by metabolic reactions Ex. Birds and mammals Ectotherms (“outside heat”) Obtain heat from environment (i.e. basking in the sun) Ex. Reptiles, amphibians, most fish, invertebrates

Warmer temperatures = higher metabolic rate Cold lizards Hummingbirds Heat stroke and frostbite in endotherms

Feedback Systems Method of maintaining internal environment Negative feedback – method for keeping body conditions within a normal range and maintaining homeostasis Positive feedback – substance or condition that acts within a system to produce more of the same activity

Negative Feedback

Negative Feedback

Negative Feedback

Positive Feedback

Comparing the Two Types of Feedback Mechanisms

How is the animal body organized?

Tissues are composed of similar cells 4 Major Categories 1. Epithelial tissue 2. Connective tissue 3. Muscle tissue 4. Nervous tissue

Tissue Type 1: Epithelial tissue Forms protective covering for the body Covers the outside of the body (skin) Lines the body cavities, hollow organs (i.e. digestive, respiratory, urinary, reproductive), and ducts (i.e. blood vessels)

Classification of Epithelial Tissue Based on shape and layers Simple epithelium One layer Ex. Found in digestive, respiratory, and circulatory system Stratified epithelium Multiple layers Ex. Found in mouth and skin Covered with many layers of dead cells These cells and others below contain keratin Makes skin water-resistant, flexible, and tough

Classification of Epithelial Tissue

Simple Squamous Epithelium APSU. 2010. http://apbrwww5.apsu.edu/thompsonj/Anatomy%20&%20Physiology/2010/2010%20Exam% OU. 2011. http://www.biosci.ohiou.edu/introbioslab/Bios171/images/lab1/simple_squamous.jpg

Simple Columnar Epithelium Goblet cell - mucus-secreting gland cell King, David. 2001. SIUC. http://www.siumed.edu/~dking2/erg/images/GI125b.jpg

Simple Cuboidal Epithelium

Stratified Squamous Epithelium NKU. 2011. http://www.nku.edu/~dempseyd/stratified%20squamous%20epithelium.gif

Pseudostratified Ciliated Columnar Epithelium Palomar. 2011. http://faculty.palomar.edu/ggushansky/histology/images/pseudostratified%20ciliated%20columnar%

Glands Single cells (i.e. goblet cells) or groups of cells (i.e. salivary, mammary, sweat) that secrete substances outside the cell 2 types of glands Exocrine Glands Endocrine Glands http://commonsensehealth.com/uploads/endocrineglands.gif

Exocrine Glands Secrete non-hormonal substances into a body cavity or onto body surface usually through a duct Sweat glands Sebaceous glands (oil glands) Salivary glands Exocrine glands in stomach and small intestine http://www.biologycorner.com/anatomy/digestive/salvary-glands.jpg http://www.gopetsamerica.com/anatomy/illustrations/pancreas.jpg

Endocrine glands Lack ducts Secrete hormones that diffuse into nearby capillaries Hormones – chemical produced that are transported by bloodstream to regulate activity of cells http://nutritiondoctordirect.com/images/endo.gif

Tissue Type 2: Connective Tissue Main function is to support and bind other tissues Cells are embedded in a matrix of extracellular substances Fluid Flexible proteins Collagen – the most abundant 4 main types: Liquid connective tissue Soft connective tissue Fibrous connective tissue Hard connective tissue

Liquid Tissue Cells are suspended in a fluid matrix Ex. Blood Cellular portion Red blood cells White blood cells Platelets (cell fragments) Extracellular portion Plasma (fluid)

Soft Connective Tissue Loose Connective Tissue Cells (fibroblasts) in jellylike matrix Cells secrete protein fibers and collagen protein Most common type of tissue in the body Found in membranes around vessels and organs, between muscles, and under skin Adipose (fat) Tissue Stores fat for energy Serves as insulation Serves as protective padding for joints and organs

Soft Connective Tissue Loose connective tissue Adipose tissue

Fibrous (Dense) Connective Tissue Cells = fibroblasts Contains collagen fibers Often densely packed in a parallel arrangement which gives flexibility and strength Ex. Tendons (connects muscle to bones) Ex. Ligaments (connects bone to bone)

Hard Connective Tissue Cartilage Thick, nonliving matrix Matrix composed of collagen which is produced by the cartilage cells Flexible and resilient Covers ends of long bones, forms framework for respiratory passages, supports ears and nose, spinal discs Bone Matrix hardened by calcium deposits Forms in concentric circles around a central canal (contains blood vessels)

Hard Connective Tissue Cartilage Bone

Tissue Type 3: Muscle Tissue Produces movement by contraction Able to shorten and relax 3 types of muscle tissue Skeletal muscle Cardiac muscle Smooth muscle

Skeletal Muscle Voluntary muscle Heavily striated Caused by fibrous proteins in the muscle cells Produces movement of the skeleton http://legacy.owensboro.kctcs.edu/gcaplan/anat/study%20guide/Image1006.gif

Cardiac Muscle Located only in the heart Involuntary muscle Cells connected by gap junctions through which electrical signals spread through heart Coordinates cell contraction

Smooth Muscle Also called visceral muscle Involuntary Not striated Produces slow, sustained contractions Found in walls of digestive tract, uterus, bladder, large blood vessels

Tissue Type 4: Nervous Tissue Makes up brain, spinal cord, nerves Body’s communication system 2 types of cells Neurons Generate electrical signals Conduct signals to other neurons, muscles, glands Neuroglial (“glue”) cells Surround, support, electrically insulate, and protect neurons Regulate composition of interstitial fluid in nervous system

Nervous Tissue Cells General structure of a neuron 1 neuron surrounded by smaller neuroglial cells

Organs include 2 or more tissues

Skin Protects body against infections and water loss Helps maintain homeostasis Contains outer layer of epithelial tissue underlain by connective tissue which contains blood vessels, nerves, muscle (sometimes), glands, and adipose

Skin

Jejunum (small intestine) Cross-section http://www.dartmouth.edu/~anatomy/Histo/GI/GI/DMS132/30.gif

Three Embryonic Germ (Tissue) Layers http://image.wistatutor.com/content/feed/tvcs/GEREM.JPG

Body Cavities

Directional Terms

Directional Terms

Organ Systems Consists of 2 or more organs working together to perform common function

11 Organ Systems

11 Organ Systems

THE END