3.2 – Human Organs & Systems Circulatory, Digestive, Respiratory, Nervous, Skeletal, Muscular, Immune, Endocrine, Reproductive, Urinary, Integumentary

Cell  Tissue  Organ Organs contain all 4 types of tissue in order to function properly: Epithelial Muscle Nervous Connective Stomach organ

Organelle  Cell  Tissue  Organ  System Some cells have more organelles than others ex: muscle cells are packed with mitochondria, WBC are packed with lysosomes, etc. Together, specialized cells form tissues that perform special functions Tissues form organs that are part of a system organs work together so the organism can survive

Example: the Circulatory System Consists of the heart, arteries, veins, & blood cells: RBC, WBC, platelets, etc. tissues: all 4 (E, M, N, C) organs: heart, blood vessels system: circulatory All function to transport nutrients, gases, and wastes to and from cells in the body

Humans Have 11 Organ Systems! Circulatory Respiratory Digestive Urinary Skeletal Muscular Nervous Immune Endocrine Reproductive Integumentary

Main Function of Each System 1. Circulatory System  transports blood, nutrients, gases & wastes 2. Respiratory System  controls breathing and exchanges gases in the lungs 3. Digestive System  takes in food, breaks it down, absorbs nutrients and removes waste 4. Urinary System  removes liquid wastes 5. Nervous System  detects changes in the environment and sends signals to parts of the body to respond 6. Skeletal System  supports, protects, & works with muscles to move parts of the body 7. Muscular System  works with bones to move parts of the body 8. Immune System  defends against infection 9. Endocrine System  makes & releases hormones to keep systems working properly 10. Reproductive System  produces offspring 11. Integumentary System  creates a waterproof barrier around body (skin, hair, nails)

Circulatory System Picks up and transports oxygen & nutrients to cells See Figure 3.20A on p. 100 Picks up and transports oxygen & nutrients to cells Carries wastes to kidneys for elimination from the body Heart contractions produce pressure so that blood can move around the body Heart valves close after blood is pushed through them to prevent blood from flowing backwards Arteries carry oxygenated blood Veins carry deoxygenated blood and wastes like CO2 that need to be removed from body remember the exception! (explained in the video) artery = away from heart vein = towards heart

Remember… Blood flows through the 4 chambers of the heart & through the lungs before being dispersed through the body

Blood in the Heart & Lungs Blood returning from the body is deoxygenated carries CO2 waste from cellular respiration Blood returning from the lungs is oxygenated bright red due to the high O2 content See Figure 3.20B on p. 100

The Path of Blood in the Body Blood from body: Vena cava  Right atrium  Right ventricle  Pulmonary arteries  Lungs  Pulmonary veins  Left atrium  Left ventricle  Aorta  Blood circulates to body

Capillaries KAP-ill-air-eez These are networks of very thin blood vessels (1 epithelial cell thick!) They deliver oxygen & nutrients and pick up waste materials from tissues in every organ in the body Trace the path of blood with your finger, starting at one point and returning to it

Quiz time! Name the 2 major functions of the circulatory system. Name the 4 main chambers of the heart. What do the valves in the heart do? With a partner, explain the path that blood takes through the body from your fingertip or your toe, back to that same body part. What are capillaries? What do they do?

The Same, but Different Read the top half of p. 101. Then with a partner, answer the following questions. 1. a) What is the difference between an open and closed system with regards to circulation? b) Give an example of an animal that would have an open system, and one that would have a closed one. 2. How is a fish’s heart different from a human’s? 3. a) How many chambers does an amphibian’s heart have? b) What does this mean then?

Respiratory System Consists of the lungs & airways Responsible for gas exchange (O2 in, CO2 out) Is connected to the circulatory system so that it can exchange gases in the blood (through capillaries) The diaphragm is a muscle that contracts when you breathe allows room for your lungs to expand so they can take in air rib cage moves up & out, causing air to be pulled into your body through your nose or mouth

Use Your Nose! The air your breathe in passes by epithelial cells in your nasal cavity cells have tiny, hair-like projections called cilia they also secrete mucus Both cilia & mucus keep foreign particles like allergens, bacteria, and toxins out of your body

Pharynx  Trachea  Bronchi Air moves from the pharynx (throat) to your trachea a small flap called the epiglottis opens and closes so no food ends up in the trachea From the trachea, the single pipe splits into two, called bronchi each bronchi goes to a lung

Bronchi  Bronchioles  Alveoli Bronchi then branch out into smaller tubes called bronchioles bronchioles are embedded within the lung tissue Bronchioles divide into tiny sacs called alveoli Capillaries surround the alveoli it is here that gas exchange takes place See Figure 3.26 on p. 104

Alveoli Tiny clusters of air sacs in the lung (sing. = alveolus) have a very thin epithelial layer gases can cross, but bacteria and other harmful substances cannot O2 and CO2 are exchanged with blood in the capillaries O2 to RBC from alveoli CO2 to alveoli from RBC RBCs contain hemoglobin, which binds O2 so that it can be carried through the body

Alveoli are the tiny heroes of the respiratory system!

Alveoli       Mouth When your diaphragm & chest muscles relax, you exhale CO2 in the alveoli is released into the air in the opposite way O2 came in When CO2 levels get too high, breathing rate increases so CO2 can be expelled quicker

The Same, but Different… again Birds, reptiles, & amphibians have lungs just like humans do these creatures have an effective gas exchange system, but it is different than ours Instead of alveoli, fish have gills Read over Figure 3.28 on p. 105 and summarize with a classmate how gills perform gas exchange just like alveoli in humans

Quiz… yahoo!! Trace the path of a breath of air in through your nose and out through your mouth. Why should you always breathe in through your nose? What is the structure in the lung where gas exchange takes place? Name 2 gases that are exchanged with blood in capillaries here. Why does your breathing rate increase when you’re exercising?

Digestive System Mechanically & chemically breaks down food so the body can use nutrients The major organs are the stomach, liver, pancreas, and intestines See Figure 3.14A on p. 97

Mouth  Pharynx  Esophagus Teeth break down food into smaller pieces Enzymes (protein) in saliva begin chemical digestion Swallowed food passes through the pharynx to the esophagus Esophagus Is a muscular tube that contracts & relaxes to push chunks of food down to the stomach Waves of muscle contraction is called peristalsis

Stomach Contains liquids called gastric juices that chemically break down the food more are highly acidic Stomach muscles mix the contents, which continues the mechanical breakdown of food churning action of stomach & gastric juices cause food to break down into a liquid Food is pushed into small intestine

Small Intestine Divided into 3 sections: 1. duodenum  where the rest of digestion takes place 2. jejunum 3. ileum  where absorption of nutrients takes place Pancreas, liver, and gall bladder release digestive enzymes into the duodenum via small tubes called ducts Walls of the small intestine are covered with little projections called villi (& microvilli) they increase the surface area so that more nutrients and water can be absorbed into the bloodstream See Figure 3.15 on p. 98 See Figure 3.16 on p. 98

Large Intestine Includes the colon, rectum, & anus (oh geez) Absorbs water, vitamins salts from digested food achieved by bacteria in the gut like E.coli Remaining (undigested) food is eliminated as feces

Sooooo… let’s recap The path of a meal from start to finish: mouth  pharynx  esophagus  stomach  small intestine  large intestine Weird facts: it takes 24 to 33 hrs for a meal to go from beginning to end of this system the small intestine is between 6 – 10 m in an adult

Quizzy, quizzy… Identify the structures A. – E. Name 3 organs that help digest food that enters the small intestine. Name the 3 sections of the small intestine. Give 4 organs in the digestive system that chemically break down food and explain how each occurs. Which part of the digestive systems mechanically breaks down food?

Urinary (Excretory) System Composed of the kidneys, ureter, bladder, urethra, and blood vessels Eliminates liquid wastes from the body Interacts closely with the circulatory & digestive systems

Kidneys: Liquid Waste’s Last Stop As blood passes through the kidneys, it is filtered and wastes are removed Remember nephrons? Those are the tiny structures within the kidneys that do the filtering Urine forms from excess water and unneeded salts in the blood (called urea) Urine is stored in the bladder and then excreted through the urethra

Nephrons

Urine trouble if you don’t know the answers to these questions! Name the 4 major structures that compose the urinary system. How is the urinary system different from the digestive system? What tiny structure in the kidney is responsible for filtering blood of its wastes?