Animal Structures & Functions Chapter 20

Introductory Activity Draw the outline of a human body Locate and draw the brain, stomach, kidneys, heart and lungs paying attention to their shapes and relative sizes

There are 12 Organ Systems in the Human Body Name them

The Nervous System Structures: Function Brain, Spinal cord, Peripheral Nerves Function Coordinates the body’s response to changes in its internal and external environments

The Integumentary System Structures: Skin, hair, nails, sweat and oil glands Function Serves as a barrier against infection and injury Helps to regulate body temperature Provides protection against uv radiation

The Respiratory System Structures: Nose, pharynx, larynx, trachea, bronchi, bronchioles & lungs, diaphragm Function Provides oxygen needed for cellular respiration and removes excess carbon dioxide from the body

The Digestive System Structures: Function Mouth, pharynx, esophagous, stomach, small & large intestines Associated organs; liver, gall bladder, pancreas Function Converts foods into simpler molecules that can be used by the cells of the body Absorbs food

The Excretory System Structures: Function Skin, lungs, kidneys, ureters, urinary bladder, urethra Function Eliminates waste products of metabolism from the body Maintains homeostasis

The Skeletal System Structures: Function Bones, cartilage, ligaments, tendons Function Supports the body Protects internal organs Allows movement Stores mineral reserves Provide a site for blood cell formation

The Muscular System Structures: Function Skeletal muscle, smooth muscle, cardiac muscle Function Works with skeletal system to produce voluntary movement Helps circulate blood and move food through the digestive system

The Circulatory System Structures: Heart, blood vessels, blood Function Brings oxygen, nutrients and hormones to cells Fights infection Regulates body temperature

The Endocrine System Structures: Function Hypothalamus, pituitary, thyroid, parathyroids, adrenals, pancrease, ovaries (), testes () Function Controls growth, development, metabolism, and reproduction

The Reproductive System Structures: Testes, epididymis, vas deferens, urethra and penis (males) Ovaries, Fallopian tubes, uterus, vagina (females) Function Produces reproductive cells In females, nurtures and protects developing embryo

The Lymphatic & Immune Systems Structures: White blood cells, thymus, spleen, lymph nodes, lymph vessels Function Helps protect the body from disease Collects fluid lost from blood vessels and returns it to the circulatory system

Homeostasis All of the organ systems work together to maintain homeostasis Homeostasis is the process by which an organism maintains a relatively stable internal environment (temperature @ 37°C, salt concentrations, elimination of wastes, delivery of nutrients and oxygen, etc.)

An Important Process While walking along a dusty path, you begin to cough. As you continue your walk, a small insect comes flying toward you. You blink and then duck so that it misses you. These actions are just a few examples of homeostasis. Homeostasis is the process by which organisms keep internal conditions relatively constant despite changes in their external environments. 1. List three other examples of homeostasis that occur in organisms. 2. Why is homeostasis important to an organism?

Homeostasis and the Control of Body Temperature

Structural Hierarchy in Animals

Major Types of Tissues Muscle Epithelial Connective Nervous

Muscle Tissue Most abundant Controls internal movement of food (digestive system) and blood (circulatory system), air (respiratory system) Controls external movement (voluntary movement)

Muscle Tissue cont…

Epithelial Tissue Covers the body’s surface and lines internal organs. Makes up glands which produce and secrete different substances, saliva, sweath, milk, hormones, etc.

Epithelial Tissue cont…

Connective Tissue Holds organs in place Pads and insulates the body (fat) Binds different parts of the body together Tendons connect muscles to bones Ligaments connect bones to bones

Connective Tissue cont…

Nervous Tissue Receives messages from the body’s external and internal environments Analyses the data Directs the response

Organs Are Made From Different Tissues

Body Plan of Simple Animal

Complex Animal Body Plan

Imaging Technology X-Rays CT Scans (computed tomography) MRI (magnetic resonance imaging) MRM (magnetic resonance microscopy) PET – (positron-emission tomography)

X - Rays 1895 Pass through soft tissues & leave shadows of the hard (bones & tumors) Problems 2-D only (anatomical structures are overlapped) Soft tissues not visible High doses cause cancer

CT Scans X-ray source circles around patient & produces several successive images at different angles Information is processed in a computer to make 3-D images Patients usually drink a special liquid to improve the contrast of the images Used to detect small differences between normal and abnormal tissues mainly in the brain and abdomen

MRI Used to show soft tissues surrounded by bone Uses powerful magnets to align hydrogen nuclei in water molecules a small pulse of radiowaves are shot at the patient and knock out the alignment of hydrogen nuclei In turn, hydrogen sends out radio signals of its own which are picked up by the MRI scanner and processed by a computer to make an image

MRM More powerful that MRI Used to study developing embryos that are very small

PET Patient is injected with a radioactive isotope Metabolically active cells take up more of the isotope that nonactive cells The isotopes emit positrons that collide with electrons in the cells and in turn release gamma rays which are picked up by the PET scanner Used mainly for studying the functions of the brain by studying the activity of different regions of the brain while the patient is performing different type of activities