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

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

How is the human body like a city?

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

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

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

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

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

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

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.

Homeostasis: Oxygen and Carbon Dioxide Concentrations respiratory system and circulatory system maintain a balance of oxygen and carbon dioxide concentrations in the blood 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 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 Exercise: muscle cells use more oxygen and give off more carbon dioxide than at rest increased oxygen need  increased breathing rate and volume increased oxygen need  increased breathing rate and volume  heart pumps faster  circulatory system increases blood supply to the limbs  heart pumps faster  circulatory system increases blood supply to the limbs Resting: breathing is shallower, heart pumps more slowly Resting: breathing is shallower, heart pumps more slowly

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

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.

The endocrine system helps regulate body conditions Controls the conditions in the body by making and releasing hormones 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 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: insulin and glucagon produced in the pancreas Ex: adrenaline makes your heart beat faster in exciting situations Ex: adrenaline makes your heart beat faster in exciting situations “rush of adrenaline” “rush of adrenaline” Are often called chemical messengers Are often called chemical messengers Target cells have special structures, called receptors, that allow them to respond to the chemical messenger Target cells have special structures, called receptors, that allow them to respond to the chemical messenger

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

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

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

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

What general area of the body are all the glands of the endocrine system in? What general area of the body are all the glands of the endocrine system in? the center the center What areas do the hormones produced in the glands generally affect? What areas do the hormones produced in the glands generally affect? all parts all parts How do the illustrations show the role of hormones as “chemical messengers”? 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 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, What are the glands of the endocrine system? pineal gland, hypothalamus, pituitary gland, thyroid, thymus, adrenal glands, pancreas, ovaries, testes pituitary gland, thyroid, thymus, adrenal glands, pancreas, ovaries, testes

Negative Feedback Regulation of hormone levels Regulation of hormone levels Adjust volume on a sound system Adjust volume on a sound system Friend says just right? stop changing the volume Friend says just right? stop changing the volume You = control center You = control center Friend = sensor 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 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 signals to a gland that hormone levels are correct and no more of the hormone is needed

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

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