Structure and Function in Living Systems

1. Structure and Function in Living Systems Chapter 8: Systems in Organisms 8.1: Systems help organisms meet their needs 8.2: Plants have several levels of organization 8.3 Animals have several levels of organization 8.4 Human health depends on a balance among systems

2. Human health depends ona balance among systems Levels of Organization • Fill in the sequential cluster diagram epithelial, muscle, nerve, connective respiratory, circulatory, nervous, skeletal heart, skin, eyes;

3. How is the human body like a city?

4. The body’s systems work all the time • Human body depends on processes that don’t stop • needs to: • Breathe • circulate blood • take in food, to digest it, and to eliminate waste materials • organ systems remain active during sleep • **working constantly to maintain the balance needed to survive

5. Body systems maintain homeostasis • Homeostasis: the ability of the body to maintain internal conditions within normal ranges • Conditions are in equilibrium = balanced • Small changes always occur internally and externally • Body must work to regulate: • Body temperature • amount of sugar in blood • oxygen and carbon dioxide levels, and water and salt balance in body fluids

6. Homeostasis: Negative Feedback Homeostasis is often maintained by a negative feedback loop

7. Homeostasis: Body Temperature • Normal internal temperature is ~ 37°C (98–99°F). • homeostatic systems for temperature: Integumentary, circulatory, muscular, respiratory, and nervous • If much above or below 37°C: • The homeostatic systems are having trouble maintaining your usual temperature • Active, or hot day  body temperature may rise • Body sweats • Evaporation of sweat from skin cools body  brings temperature back down

8. Homeostasis: Ion Concentrations • Kidneys help keep body water volume constant • drink a lot of water kidneys release more water in urine • do not drink enough water kidneys make less urine • Why? • To maintain the proper concentrations of ions and other substances in the blood • Concentration: amount of one substance that is dissolved in another substance • The less water, the higher the concentration of dissolved substances • The more water, the lower the concentration

9. Homeostasis: Ion Concentrations • Ion: an atom of an element that has gained or lost one or more electrons – “charged” particles (+ or -) • important to many body processes: • movement of substances across cell membranes • sending of nerve impulses • Electrolytes: sodium, potassium, chloride, and calcium • skin tastes salty after sweating: • Sweat contains salts, ex: Sodium and chloride together • sports drinks contain salts (electrolytes!)

10. Electrolytes and salts, in ion form, are substances that conduct electric current. Electrolytes in human body fluids operate similarly to the currents caused by electrolytes in batteries. The positive and negative charges of the ions cause them to move toward concentrations of the opposite charge. Electrolytes such as sodium, potassium, calcium, magnesium, and chloride ions in the human body help fluids flow across cell membranes and help nerve impulses travel.

11. Homeostasis: Oxygen and Carbon Dioxide Concentrations • respiratory system and circulatory system maintain a balance of oxygen and carbon dioxide concentrations in the blood • These dissolved gases are carried by the blood and delivered to and from the tissues in plasma • Exercise: muscle cells use more oxygen and give off more carbon dioxide than at rest • increased oxygen need increased breathing rate and volume • heart pumps faster circulatory system increases blood supply to the limbs • Resting: breathing is shallower, heart pumps more slowly

12. Homeostasis: Other Nutrients • Liver • breaks down large food molecules—carbohydrates, fats, and proteins—into nutrients • stores glucose, vitamins, and iron • produces bile (a fluid used in digestion) • breaks down alcohol, drugs, and other toxic chemicals • Filters, stores, and releases materials • Pancreas • Part of digestive and endocrine systems • helps maintain blood glucose levels

13. Some people with diabetes are unable to make enough insulin to regulate their blood sugar. They often need to take injections of insulin to keep their blood sugar in a normal homeostatic range.

14. The endocrine system helps regulate body conditions • Controls the conditions in the body by making and releasing hormones • Hormones: chemicals that are made in one organ, travel through the blood, and produce an effect in target cells • Ex: insulin and glucagon produced in the pancreas • Ex: adrenaline makes your heart beat faster in exciting situations • “rush of adrenaline” • Are often called chemical messengers • Target cells have special structures, called receptors, that allow them to respond to the chemical messenger

15. Hormones and Glands • Glands: specialized - tissues main structures of the endocrine system • Many glands in the body produce hormones circulatory system • Pineal Gland: • Tiny organ sizes of a pea • near the center of the brain • sensitive to light • produces a hormone essential to body rhythms • Ex: sleep • Plays a role in maintaining body temperatures, in reproducing, and in aging

16. Hormones and Glands • Hypothalamus • connects the nervous and endocrine systems • Produces hormones that control the release of hormones produced by the… • Pituitary Gland • base of the brain • director of the endocrine system • produces hormones that control growth, sexual development, and the absorption of water into the blood by the kidneys

17. Hormones and Glands • Thyroid Gland • releases hormones necessary for • Growth • Metabolism • regulation of calcium • Thymus Gland • helps the body fight disease by controlling the production of white blood cells called T cells • Adrenal Glands • secrete about 30 different hormones • regulate carbohydrate, protein, and fat metabolism and water and salt levels in the body • adrenaline –in response to stress • makes your heart beat faster • allows you to react quickly in dangerous or exciting situations

18. Hormones and Glands • Pancreas • part of both the digestive system and endocrine system • secretes insulin and glucagon • Regulate levels of glucose in the blood • Ovaries (female) and Testes (male) • secrete hormones that control sexual development • ovaries make more estrogen • testes make more testosterone • the different amounts of give males and females different characteristics

19. What general area of the body are all the glands of the endocrine system in? • the center • What areas do the hormones produced in the glands generally affect? • all parts • How do the illustrations show the role of hormones as “chemical messengers”? • The glands are located throughout the body and are able to “deliver” hormones wherever the body needs them • What are the glands of the endocrine system? pineal gland, hypothalamus, • pituitary gland, thyroid, thymus, adrenal glands, pancreas, ovaries, testes

21. Negative Feedback • Regulation of hormone levels • Adjust volume on a sound system • Friend says just right? stop changing the volume • You = control center • Friend = sensor • Feedback = information coming back to a control center from a sensor that tells the control center what it needs to do to maintain a level within an ideal range • signals to a gland that hormone levels are correct and no more of the hormone is needed

22. Homeostasis may be disrupted • Signs of imbalance range from a mild cold, to dangerous overheating of the body, to serious and even fatal diseases • Sneezing help defends the body from foreign substances • Pathogens (bacteria or virus) in the body signal the immune system • Symptoms begin to go away when homeostasis is restored • Exercising  usually sweat • lose too much water dehydration • Signs of heat exhaustion: dehydration, dizziness, nausea, fainting, and a dangerous drop in blood pressure • Heat stroke – possible if a person stops sweating  temperature rise • Hypothermia - body temperature too low

23. Homeostasis may be disrupted • hormone imbalances can cause serious diseases • Pancreas normally maintains glucose balance in your blood by releasing insulin and glucagon as needed • Imbalance diabetes • failure of other organs, heart disease, blindness, and kidney damage • Kidneys continually filter the blood, taking out waste products • Malfunction? • Dialysis: blood is circulated through an artificial kidney machine that filters out the wastes (3 sessions/week!)