Animal Tissues and Organ Systems Chapter 20

Key Concepts Types of tissues Organ systems Four tissues types organized into organs Epithelial Connective Muscle Nervous Organ systems Three embryonic tissues are source of all adult organs Each organ system has specialized function

Stem Cells Undifferentiated cells with potential to develop into many cell types Embryonic stem cells, more versatile Adult stem cells, less versatile

Body Organization Tissue Organ Organ system Group of cells performing same task Organ Two or more tissues performing same task Organ system Two or more organs performing same task

Tissues Groups of cells and intercellular substances that interact in one or more tasks Example: muscle tissue

Organs Group of tissues organized to perform a task or tasks Example: Heart is an organ that pumps blood through body Heart consists of muscle tissue, nervous tissue, connective tissue, and epithelial tissue

Organ Systems Groups of organs that interact physically and/or chemically to perform a common task Example: Circulatory system includes heart, arteries, and other vessels that transport blood through the body

Homeostasis Stable operating conditions in the internal environment Brought about by coordinated activities of cells, tissues, organs, and organ systems

4 Types of Tissues Muscle tissues Nervous tissues Epithelial tissues Connective tissues Muscle tissues Nervous tissues

Type 1: Epithelial Tissues Sheet-like, line body surfaces, cavities, ducts, and tubes One free surface faces a body fluid or the environment simple squamous epithelium basement membrane connective tissue

Secretory organs derived from epithelium Glands Secretory organs derived from epithelium Exocrine glands have ducts or tubes Salivary and sweat glands Secrete to the OUTSIDE Endocrine glands are ductless Adrenals and pituitary Secrete to the INSIDE exo = out endo = in

Type 2: Connective Tissues Most abundant tissues in the body Different types Soft Beneath skin, encapsulates organs Specialized Cartilage Bone Adipose (fat) Blood Fibroblasts Secrete “ground substance” forming polysaccharides Secrete collagen, the most abundant protein in the human body

Soft Connective Tissues Loose connective tissue Dense, irregular connective tissue Dense, regular connective tissue

white blood cell platelet red blood cell Fig. 20-3g, p.342

Type 3: Muscle Tissue Cells contract when stimulated Moves body and specific body parts 2 types, 3 classes Striated Skeletal Cardiac Not striated Smooth

Skeletal Muscle Attaches to and moves bones Long, cylindrical cells Striated cells Voluntary control nucleus

Cardiac Muscle Present only in heart Cells are branching Ends joined by communication junctions Cells striated Not under voluntary control where cells meet

Smooth Muscle Located in soft internal organs and blood vessels Cells taper at ends Cells not striated Not under voluntary control cell nucleus

Type 4: Nervous Tissue Detects stimuli, integrates information, and relays commands for response Consists of excitable neurons and supporting neuroglial cells

This allows the cells to: Neurons “Excitable” cells This means that: Stimulus sends electrical impulse along plasma membrane because of specific proteins This allows the cells to: Transmit information to other neurons, muscles or glands

Neuron Anatomy http://webspace.ship.edu/cgboer/theneuron.html

11 Major Organ Systems Integumentary Nervous Muscular Skeletal Circulatory Endocrine Lymphatic Respiratory Digestive Urinary Reproductive I promise that you will be tested on these 11 systems. At the very least, you will need to know the functions of each system. All of this info is on page 344.

11 Major Organ Systems Integumentary System Nervous System Muscular System Skeletal System Circulatory System Endocrine System Fig. 20-6, p.344a1

11 Major Organ Systems Lymphatic System Respiratory System Digestive System Urinary System Reproductive System Fig. 20-6a2, p.344

Skin: An Organ System Integumentary Epidermis: Stratified epithelium Dermis: Dense connective tissues Hypodermis: Loose connective tissue and adipose tissue

Functions of Human Skin Protects body from injury, dehydration, UV radiation, and some pathogens Helps control temperature Receives external stimuli Involved in vitamin D production Important stuff, this

Sun Damages Skin UV light stimulates melanin production tans skin Tan protects inner layers against UV damage UV exposure causes elastin fibers to clump skin to age prematurely skin cancer

The Epidermis is an Epithelial Tissue Porphyria and vampirism

Where do Tissues and Organ Systems Come From? Primary Tissues Three primary tissues in vertebrate embryos give rise to all adult tissues: Ectoderm Mesoderm Endoderm ecto=out meso=middle endo=inside

Primary Tissues (cont’d) Ectoderm Outer layer of skin Nervous tissue Mesoderm Muscles, bones and most of the circulatory, reproductive and urinary systems Endoderm Lining of the digestive tract, as well as the liver, lungs and pancreas

5 Major Body Cavities Cranial cavity Spinal cavity Thoracic cavity Abdominal cavity Pelvic cavity