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Human Body Systems
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Organization in Multi-cellular Organisms
the smallest functional unit of life Tissue a group of similar cells that perform a particular function Organ many groups of tissues that work together Organ System groups of organs that work together to perform a specific function Organism consists of several organ systems that function together
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Tissue Types Muscle Nervous Epithelial Connective
Controls the internal movement of materials in the body and external movements of body parts Nervous Receives and transmits messages Epithelial Covers the surface of the body and lines internal organs Connective Holds organs in place and binds body parts together
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11 organ systems
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Digestive System Structures Accessory Structures Functions
mouth, pharynx, esophagus, stomach, small intestine, large intestine Accessory Structures salivary glands, pancreas, liver, gallbladder Functions Breaks down food into smaller pieces Absorbs nutrients into blood stream Eliminates indigestible food waste
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Pathway of Food Chewing (mastication) physically breaks down food
Mouth: Chewing (mastication) physically breaks down food Salivary Glands: Saliva contains the enzyme amylase which begins the chemical digestion of carbs and lubricates food so it’s easier to swallow Pharynx: Beginning of throat Epiglottis or a flap of tissue that covers the trachea (windpipe) to prevent food from entering the lungs while swallowing
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Pathway of Food Esophagus: Stomach:
Waves of muscle contractions (peristalsis) push food down toward the stomach Stomach: Muscular contractions continue the mechanical digestion of food Secretes acid which kills bacteria in food and activates enzymes Secretes the enzyme, pepsin, which begins the chemical digestion of proteins Secretes mucus which protects the stomach from acid and enzymes
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Small Intestine: Pathway of Food
Chemical digestion of carbs, proteins, and fat finishes and nutrients are absorbed Very long and lined with villi or projections that increase surface area for more absorption of nutrients Peristalsis moves food through small intestine Liver, gallbladder, and pancreas secrete chemicals into the small intestine to aid in digestion
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Accessory Organs: Food never enters these organs
Pancreas: Secretes enzymes into small intestine to break down fats, carbohydrates, and proteins Liver: Stores extra glucose as glycogen Makes vitamin A and bile (which breaks down fats) and neutralizes food coming from the stomach Breaks down alcohol, drugs, bacteria, old blood cells Gallbladder: Stores bile made by the liver and secretes it into the small intestine
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Large Intestine (including rectum and anus):
Pathway of Food Large Intestine (including rectum and anus): Absorbs water from waste and then eliminates indigestible food waste (fiber)
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Summary of Food Breakdown
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Respiratory System Structures Functions: nose pharynx larynx trachea
bronchi bronchioles lungs Functions: Provides oxygen needed for cellular respiration Removes excess carbon dioxide from the body Filters debris from air being inhaled
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Breathing Inhalation Exhalation
diaphragm contracts expanding the volume of the chest cavity causing air to rush into the lungs Exhalation diaphragm relaxes decreasing the volume of the chest cavity causing air to be forced out of the lungs
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GAS EXCHANGE IN THE LUNGS
Air enters the nose and passes through the pharynx, larynx, trachea, bronchi, and bronchioles. Clusters of tiny air sacs called alveoli are at the end of each bronchiole. Alveoli are surrounded by capillaries allowing for gas exchange between blood and lungs.
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Circulatory System Structures Functions: heart blood vessels blood
Transports oxygen, nutrients, hormones, and wastes around body Helps fight infection Regulates body temperature
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Circulatory System: Blood Vessels
Arteries Carry blood away from heart Surrounded by muscles to move blood Capillaries Tiny vessels (only one cell layer thick) that allow diffusion of materials between blood and cells Where arteries and veins meet Veins Carry blood back to heart Have valves to prevent backflow
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Blood Contents Plasma Erythrocytes (red blood cells)
fluid part of blood that carries nutrients, enzymes, hormones, and wastes Erythrocytes (red blood cells) contain hemoglobin which carries oxygen Leukocytes (white blood cells) attack foreign substances by engulfing them or producing antibodies to destroy them Platelets cell fragments that help blood clot when needed
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Oxygenated blood flows back to the heart.
De-oxygenated blood is pumped from the heart to the lungs where it picks up oxygen. Oxygenated blood flows back to the heart. Oxygenated blood is then pumped out to body cells to deliver oxygen and pick up carbon dioxide. De-oxygenated blood flows back to the heart and the cycle starts again.
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Circulatory System: Heart blood flow
Pacemaker Bundle of nerves, tell heart to contract Left Ventricle Pumps blood to the body through aorta Left Atrium Receives blood returning from lungs Right Ventricle Pumps blood to lungs (waste is removed, oxygen added) Right Atrium Receives blood returning from the body through vena cava
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Nervous System Structures Function: brain spinal cord
peripheral nerves Function: Contains receptors to perceive changes in environment Integrates and processes information received from internal and external stimuli Controls and coordinates functions throughout the body
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Nervous System: Neurons
Messages travel down each neuron in electrical form. Neurons consist of 3 parts: Cell body contains the nucleus and performs normal cell functions Dendrites receive messages from other cells Axon sends messages to other cells Neurons transmit messages to other cells at the synapse using chemicals (neurotransmitters). Neurotransmitters released at the axon of one cells transmit a message to the dendrites of another cell.
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Receiving & Sending Messages
Sensory Neurons gather information from in and around your body and send information to the brain and spinal cord for processing. Brain integrates information to make decisions on what reaction should be. Motor Neurons send impulses from the brain and spinal cord to organs and/or muscles to produce a response.
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Sensory & Motor neurons
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Muscular System Structures Functions Skeletal Muscle Smooth Muscle
Cardiac Muscle Functions Works with skeletal system to produce voluntary movement Helps circulate blood and move food through the digestive system Helps produce heat for the body
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Three Types of Muscle: Skeletal Smooth Cardiac
Attached to bones by tendons Responsible for voluntary movement Smooth Controls digestion, breathing, circulation Involuntary Cardiac heart muscle
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Voluntary Muscle Contractions
Voluntary muscles work in opposing pairs so when one muscle contracts, the other one relaxes Example: When the bicep muscle (a flexor) contracts and the tricep muscle relaxes, the arm bends. When the tricep muscle (an extensor) contracts and the bicep muscle relaxes, the arm straightens.
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Skeletal System An adult human body has approx. 206 bones organized into an internal framework called the skeleton Structures: Bones Cartilage Ligaments Tendons Functions: Supports the body and protects internal organs Allows movement Stores mineral reserves Provides a site for blood cell formation
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Bone Structure Bones Compact bone Spongy bone
network of cells and protein fibers supported by deposits of calcium Compact bone forms outside of bones / very dense with canals running though for blood vessels and nerves Spongy bone forms inside of bones /less dense and resembles latticework Cavities within bones contain bone marrow which produces red blood cells, some white blood cells, and blood platelets.
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Joints Joints Tendons Ligaments Cartilage
where bones are joined together Tendons hold muscles to bone Ligaments hold bones to bones Cartilage protects the bone by covering parts that rub together when joints move
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Integumentary System Structures: Functions: skin hair nails
sweat glands oil glands Functions: Serves as a barrier against infection and injury Helps to regulate body temperature Provides protection against ultraviolet radiation from the sun
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Close-up of Integumentary System
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Excretory System Structures: Functions: kidneys ureters
urinary bladder urethra Functions: Filters metabolic waste from the body Maintains homeostasis by regulating the water content of the blood Excretes urinary waste products
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Waste-laden blood enters the kidneys through the renal artery.
How do the kidneys work? Urine travels down the ureters, gets stored in the bladder, and is expelled from the body through the urethra. Filtered blood is returned to the circulatory system through the renal vein. Excess water and wastes are filtered out of the blood by the kidneys and collected as urine. Waste-laden blood enters the kidneys through the renal artery.
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Lymphatic System Structures: Functions: Spleen
thymus, spleen, lymph nodes, lymph vessels, white blood cells Functions: Helps protect the body from disease Spleen filters blood, destroying damaged red blood cells and platelets Helps absorb fats and certain vitamins from intestines into blood
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Endocrine System Structures: Function:
hypothalamus, pituitary gland, pineal gland, thyroid gland, parathyroid glands, thymus gland, adrenal glands, pancreas, ovaries (females), testes (males) Function: Secretes hormones that control growth, development, metabolism, and reproduction
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Reproductive System Male Structures Functions Female Structures testes
epididymis vas deferens urethra penis Functions Produces reproductive cells Males deliver reproductive cells to females Females nurture and protect developing embryo Female Structures ovaries Fallopian tubes uterus vagina
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Feedback Control Consists of a sensor, a control center, and an effector pathway A feedback system uses the consequences of the process (too much or too little produced) to regulate the rate at which the process occurs Helps to maintain homeostasis Feedback systems are used to control and regulate processes in the body.
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Feedback Control Example: Body Temperature
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