Unit 4 Homeostasis. The term homeostasis refers to the body s attempt. Your body systems must to maintain a stable internal environment -

Transcription

1 Unit 4 Homeostasis The term homeostasis refers to the body s attempt Your body systems must to maintain a stable internal environment - The body is trying to maintain, through a series of monitored adjustments.

2 This system of active balance requires constant about body conditions. Conditions included : All homeostatic control systems have three functional components:

3 (monitors) located in signal a once homeostasis is disrupted. The coordinating centre sends a signal to the appropriate, which restores balance. Example When exercising increase in the blood. (monitor) in the are stimulated The (coordinating centre) signals (regulator) to increase the of breathing.

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5 Feedback Systems Mechanisms that make adjustments to are referred to as systems. This type of control circuit is called feedback because the response the original stimulus. Think body temperature! feedback mechanisms prevent changes from becoming too. Most mechanisms in operate on this way.

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7 There are also feedback loops: In, the response the original stimulus. Think labour contractions.

8 A decrease in (pregnancy hormone) initiates small of the uterus The contractions (hormone), which causes As the baby moves along there is a greater release of. This continues.

9 Thermoregulation Mammals and birds are ; they maintain a regardless of their surroundings.

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12 The Urinary System During harmful products are produced and must be.

13 Example: Excess in the diet is often converted into. The in protein must be removed ( in liver) and discarded by the body. The byproduct of this process is a, water-soluble gas: The liver therefore into the less toxic substance

14 Urinary System Anatomy

15 Blood flows into the kidneys via the Wastes are filtered and sent to the. From the bladder urine travels through the into the

16 An outer layer of connective tissue, the encircles the kidney.an inner layer, the, is found beneath the cortex. A hollow chamber, the, joins the kidney with the.

17 Nephrons The functional units of the kidneys. The, branches into and eventually to capillaries which reside in the. The capillaries leave the within (not venules) Next blood flows into a net of

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20 The glomerulus is surrounded by a. Fluids to become urine leave the blood and enter the Bowman s capsule. The fluid moves from here into the, down to the, and into the, finally emptying into the.

21 Urine formation depends on three functions

22 1. Filtration As blood moves through the into the it's from about 25 mm Hg to 65 mm Hg Because materials move from, solutes in the blood pass from the. Some molecules are and therefore remain in the blood.

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25 2. Reabsorption If not for, you would form of urine each minute! In reality only of urine is formed for every of fluids filtered into the occurs by both active ( ) and transport (no required). occurs until the of a substance is reached. Ex. Excess.

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27 3. Secretion Secretion is the. Nitrogen-containing wastes, excess Like reabsorption, occurs by.

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35 Fluid Balance The body adjusts for: by increasing output. - or decreased water intake by output. The process also requires the

36 Regulating ADH (ADH) helps regulate the of body fluids ADH causes the to increase water. More ADH, more ADH, is produced in the and stored in the. releases ADH into the.

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39 in the hypothalamus detect changes in. When you water intake or water loss blood solutes become. This increases the (think pulling pressure or blood.).

40 Water moves into the, causing the cells of the Message sent - Kidneys now,(more concentrated urine), can't increase any further.

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43 The shrinking of the cells of the hypothalamus also As you drink fluid and (concentration of solutes decreases) fluids move from the. The cells, and the pituitary slows, causing to be reabsorbed from the.

44 Strange but True: Drinking Too Much Water Can Kill In a hydration-obsessed culture, people can and do drink themselves to death. Hyponatremia - means having a blood sodium concentration below 135 millimoles per liter. Severe cases of hyponatremia can lead to water intoxication. When a person drinks too much water in a short period of time, the kidneys cannot flush it out fast enough. Drawn to regions where the concentration of salt and other dissolved substances is higher, excess water leaves the blood and ultimately enters the cells, which swell like balloons to accommodate it. Most cells have room to stretch because they are embedded in flexible tissues such as fat and muscle, but this is not the case for neurons. Brain cells are tightly packaged inside a rigid boney cage, the skull, and they have to share this space with blood and cerebrospinal fluid.

45 Almost all water is reabsorbed in the proximal tubule. Most of the rest of the nephron is impermeable to water ADH makes the upper part of the distal tubule and collecting duct permeable to water, allowing greater reabsorption, and a more concentrated urine.

46 Kidneys and Blood Pressure The kidneys help regulate blood pressure by. The hormone (from glands) acts on the to increase, causing high outside of the nephron so moves out.

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49 ph Balance The kidneys also help maintain ph balance. the ph of the body. Most foods as well as cellular respiration, produce that to produce. This will is maintained by that absorb or ions that act as bases.

50 The buffer system of the blood ions; however, the buffer must be. This is where the kidneys come in. They.

51 The Endocrine System The integration of body functions depends These are produced by cells in of the body that affect cells in body. Hormones produced in and secreted directly into the are referred to as. The system together provide control of. The system is designed to over a duration. ( hormones sustain development for years)

52 Hormones (about ) can be classified according to their. - They affect many cells. a. -regulates the development of the. b. - regulates c. is produced in times of. a. - regulates levels in the body b. - stimulates cells to produce enzymes.

53 Hormones do not. Cells may have for one. The number of receptors found on Two main groups of hormones, which differ in The first group,, are made from and includes and The second group,, includes enter cells and combine with located in the. then moves into the and attaches to, activating a that sends a message to the, to begin producing a specific.

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55 combine with on the cell. The form a that activates the production of an enzyme called. The enzyme converts which activates enzymes in the to carry out their normal functions

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57 The Pituitary Gland The controls many other. It is connected to the (homeostasis). produces and stores. The stimulates the release of by the. Composed of the lobe.

58 The lobe of the stores and releases hormones, like, produced by the.

59 The produces its own but is still regulated by the adrenocorticotropic hormone

60 Some hormones are produced by the hypothalamus and are which control the from the lobe of the pituitary. The releasing factor, called, inhibits the secretion of a pituitary hormone that in women who have given birth.

61 Other Glands...

62 Thyroid gland Thyroid hormones. Major hormones are The thyroid hormones contain deficiency can lead to a disorder called

63 Pancreas Two functions. 1. into the small intestine. 2. secrete to regulate the level. Adrenal Glands These sit on top of. The medulla secretes and The cortex secretes. (anti-inflammatory - suppress the immune system)

64 Gonads The secretion of by the gonads is controlled by pituitary gland hormones such as While both make some of of the hormones, typically secrete primarily including testosterone. Female make in varying amounts

65 Pineal gland This gland is located near the and secretes. Melatonin promotes It also affects functions by depressing the activity of the, and affects functions.

66 Hormones and Glucose The pancreas contains two types of cells, one of which produces hormones. These cells are part of structures called the The islets contain. cells produce - released when causes cells to become.

67 cells produce - released when blood sugar. Glucagon promotes conversion of.

68 Diabetes Caused by insufficient production. Left untreated, can cause, nerve damage. Without enough (hyperglycemia). - The kidneys are unable to - High [glucose] in the of the plasma - Experience levels. - Cells look for other sources of like -, (product of excessive ), can be produced There are three main types of. - Type 1 diabetes occurs when the (10% of people) - Type 2 diabetes - or of the insulin that the body does can be controlled with ( 90% of people) -, is a temporary condition that occurs in 2% to 4% of pregnancies

69 Canadian and assistant, who was a graduate student in biochemistry, isolated the hormone from the pancreas that when that had their, stopped diabetes symptoms In 1923, was awarded the Nobel Prize for.

70 Recall that the adrenal glands produce. In a stress situation, are released from the into the blood. They cause levels to rises. ( ) Increased level ensures that a will be available for the. These hormones also increase.

71 Recall the adrenal cortex produces a type of hormone called glucocorticoids (blood glucose levels). Cortisol, increases the level of amino acids in the blood to help the body recover from stress. The amino acids are converted into glucose by the liver, raising the level of blood sugar. Increased glucose levels provides energy for cell recovery. Any of the amino acids not converted can be used to repair damaged cells.

72 When the brain identifies stressful situations.

73 Hormones and Metabolism 3 endocrine glands that affect metabolism:

74 1. The thyroid gland produces two important thyroid hormones: - - they regulate and differentiation of tissues.

75 Individuals who secrete do not nutrients as quickly Excess is eventually converted into. Any left over is converted into. These people experience This is known as.

76 Control of thyroid hormones is through Nerve cells secrete which stimulates the pituitary to release is carried by the blood to the, which, in turn,. Thyroxine raises Thyroxine inhibits from the hypothalamus, thus turning off the production of.

77 The thyroid gland also, a hormone that acts on to lower the level of.

78 2. Four small within thyroid gland respond to in the blood and stimulate the release A rise in PTH levels causes the. PTH causes while promoting calcium release from. Once PTH levels have, the release of PTH. Calcium levels signal both the. Very high levels of PTH can cause problems like the.

79 3. The effects of are evident when too much or too little is produced. Low secretion can High secretions can. Growth hormone affects, but are affected most.

80 In soft tissues and bone It does this by while inhibiting Growth hormone also stimulates. As you ages, growth hormone production begins to.