1. travismulthaupt.com Chapter 45 Hormones and the Endocrine System

2. Internal Communication  Animals have 2 systems of internal communication and regulation:  1. The nervous system.  2. The endocrine system.  Animals have 2 systems of internal communication and regulation:  1. The nervous system.  2. The endocrine system.

3. 1. The Nervous System  The nervous system is the pathway of communication involving high speed electrical signals.  There are two portions to it:  CNS  PNS  The nervous system is the pathway of communication involving high speed electrical signals.  There are two portions to it:  CNS  PNS

4. Nervous Tissue  Senses stimuli and transmits nerve impulses from one part of the body to the next.  The neuron is the functional unit.  Axon  Dendrite  Senses stimuli and transmits nerve impulses from one part of the body to the next.  The neuron is the functional unit.  Axon  Dendrite

5.  Near its end, an axon divides into several branches, each ending in a synaptic terminal. Copyright ©2005 Pearson Education, Inc. Publishing as Pearson Benjamin Cummings. All rights reserved. What is a nerve?—Form Fitting Function

6. http://biologyclass.neurobio.arizona.edu/images/synapse2.jpg What is a nerve?—Form Fitting Function  The synapse is the site of communication between one nerve and another.

7. What is a nerve?—Form Fitting Function http://biologyclass.neurobio.arizona.edu/images/synapse2.jpg  Neurotransmitters transmit the signal from a pre- synaptic cell to a post-synaptic neuron.

8. Synaptic Transmission  The transmission of information from the presynaptic neuron to the postsynaptic neuron due to an action potential can trigger short and long term changes— membrane potential or signal cascades. http://biologyclass.neurobio.arizona.edu/images/synapse2.jpg

9. How Do Nerve Systems Work?  Information processing by the nervous system consisting of 3 stages:  1. Sensory input  2. Integration  3. Motor output  Information processing by the nervous system consisting of 3 stages:  1. Sensory input  2. Integration  3. Motor output

10. How Do Nerve Systems Work?  These three stages are handled by specialized neurons.

11. How Do Nerve Systems Work?  1. Sensory neurons transmit information from sensors that detect external stimuli and internal conditions.  These receptors are usually specialized neurons or epithelial cells.  1. Sensory neurons transmit information from sensors that detect external stimuli and internal conditions.  These receptors are usually specialized neurons or epithelial cells.

12. How Do Nerve Systems Work?  2. Interneurons integrate and analyze sensory input. They allow the spinal cord to work independently of the brain and provide reflexes.

13. How Do Nerve Systems Work?  This reflex is an automatic response to certain stimuli and acts to protect the body from harm—think about touching something hot.

14. How Do Nerve Systems Work?  2. These interneurons provide inhibitory signals to opposing muscles allowing the reflex to produce the desired result.

15. How Do Nerve Systems Work?  The CNS also provides the integrative power for the organism— specifically the brain.

16. How Do Nerve Systems Work?  3. Motor output leaves the CNS via motor neurons which communicate with effector cells eliciting a change.

17. How Do Nerve Systems Work?  These motor neurons can be due to voluntary control, or involuntary control.

18. 2. The Endocrine System  The endocrine system is all of the animal’s hormone secreting cells.  The endocrine system coordinates a slow, long-lasting response.  The endocrine system is all of the animal’s hormone secreting cells.  The endocrine system coordinates a slow, long-lasting response.

19. Endocrine Glands  Endocrine glands are hormone secreting organs.  They are ductless glands.  Their product is secreted into extracellular fluid and diffuses into circulation.  Endocrine glands are hormone secreting organs.  They are ductless glands.  Their product is secreted into extracellular fluid and diffuses into circulation.

20. Endocrine and Nervous Systems  It is convenient to think of the nervous system and the endocrine as separate.  They are actually very closely linked.  Neurosecretory cells are specialized nerve cells that release hormones into the blood.  They have characteristics of both nerves and endocrine cells.  It is convenient to think of the nervous system and the endocrine as separate.  They are actually very closely linked.  Neurosecretory cells are specialized nerve cells that release hormones into the blood.  They have characteristics of both nerves and endocrine cells.

21. Neurosecretory Cells  The hypothalamus and the posterior pituitary gland contains neurosecretory cells.  These produce neurohormones which are distinguishable from endocrine hormones.  Some hormones serve as both endocrine hormones and neurotransmitters.  The hypothalamus and the posterior pituitary gland contains neurosecretory cells.  These produce neurohormones which are distinguishable from endocrine hormones.  Some hormones serve as both endocrine hormones and neurotransmitters.

22. Neurosecretory Cells  They can stimulate a response, or they can induce a target cell to elicit a response.  For example, a suckling infant and oxytocin release is an example.  They can stimulate a response, or they can induce a target cell to elicit a response.  For example, a suckling infant and oxytocin release is an example.

23. Biological Control Systems  Recall,  These are comprised of a receptor/sensor which detects a stimulus and sends information to a control center that controls an effector.  The control center processes the information and compares it to a set point.  The control center sends out processed information and directs the response of the effector.  Recall,  These are comprised of a receptor/sensor which detects a stimulus and sends information to a control center that controls an effector.  The control center processes the information and compares it to a set point.  The control center sends out processed information and directs the response of the effector.

24. 3 General Hormonal Pathways  1. A simple endocrine pathway.  2. A simple neurohormone pathway.  3. A simple neuroendocrine pathway.  1. A simple endocrine pathway.  2. A simple neurohormone pathway.  3. A simple neuroendocrine pathway.

25. 1. A Simple Endocrine Pathway  A stimulus elicits a response on an endocrine cell causing a hormone release.  The hormone diffuses into the blood where it reaches a target effector eliciting a response.  A stimulus elicits a response on an endocrine cell causing a hormone release.  The hormone diffuses into the blood where it reaches a target effector eliciting a response. Copyright ©2005 Pearson Education, Inc. Publishing as Pearson Benjamin Cummings. All rights reserved.

26. 1. A Simple Endocrine Pathway  For example:  A low glucose level in the blood stimulates the pancreas to release glucagon.  Glucagon acts on liver cells to release glycogen.  Glycogen breaks down into glucose and gets into the blood.  For example:  A low glucose level in the blood stimulates the pancreas to release glucagon.  Glucagon acts on liver cells to release glycogen.  Glycogen breaks down into glucose and gets into the blood. Copyright ©2005 Pearson Education, Inc. Publishing as Pearson Benjamin Cummings. All rights reserved.

27. 2. Simple Neurohormone Pathway  In the simple neurohormone pathway, a stimulus travels via a sensory neuron to the hypothalamus/posterior pituitary gland.  Neurosecretory cells here release hormones into the blood.  These hormones travel to the target cells and elicit a response.  In the simple neurohormone pathway, a stimulus travels via a sensory neuron to the hypothalamus/posterior pituitary gland.  Neurosecretory cells here release hormones into the blood.  These hormones travel to the target cells and elicit a response. Copyright ©2005 Pearson Education, Inc. Publishing as Pearson Benjamin Cummings. All rights reserved.

28. 2. Simple Neurohormone Pathway  For example:  A suckling infant’s stimulation is sent via a sensory neuron to the hypothalamus/posterior pituitary where oxytocin is made and released into the blood.  The hormones travel to the smooth muscle in the breast which responds by contracting and releasing milk.  For example:  A suckling infant’s stimulation is sent via a sensory neuron to the hypothalamus/posterior pituitary where oxytocin is made and released into the blood.  The hormones travel to the smooth muscle in the breast which responds by contracting and releasing milk. Copyright ©2005 Pearson Education, Inc. Publishing as Pearson Benjamin Cummings. All rights reserved.

29. 3. A Simple Neuroendocrine Pathway  A stimulus sends the signal to the hypothalamus via a sensory neuron.  The neurosecretory cells of the hypothalamus release hormones into the blood.  These act on endocrine cells to release different hormones into the blood.  These hormones have an effect on target cells and elicit a response.  A stimulus sends the signal to the hypothalamus via a sensory neuron.  The neurosecretory cells of the hypothalamus release hormones into the blood.  These act on endocrine cells to release different hormones into the blood.  These hormones have an effect on target cells and elicit a response. Copyright ©2005 Pearson Education, Inc. Publishing as Pearson Benjamin Cummings. All rights reserved.

30. 3. A Simple Neuroendocrine Pathway  For example:  Neural and hormonal signals tell the hypothalamus to secrete prolactin releasing hormone.  This hormone travels through the blood to the anterior pituitary which releases prolactin.  Prolactin travels through the blood to the mammary glands stimulating milk production.  For example:  Neural and hormonal signals tell the hypothalamus to secrete prolactin releasing hormone.  This hormone travels through the blood to the anterior pituitary which releases prolactin.  Prolactin travels through the blood to the mammary glands stimulating milk production. Copyright ©2005 Pearson Education, Inc. Publishing as Pearson Benjamin Cummings. All rights reserved.

31. Positive and Negative Feedback  Recall,  Positive feedback acts to reinforce the stimulus. It leads to a greater response.  Negative feedback acts to reduce the response of the stimulus.  Recall,  Positive feedback acts to reinforce the stimulus. It leads to a greater response.  Negative feedback acts to reduce the response of the stimulus.

32. Molecules Functioning as Hormones  There are 3 major classes of molecules that function as hormones:  1. Proteins/peptides-water soluble.  2. Amines-water soluble.  3. Steroids-not water soluble.  There are 3 major classes of molecules that function as hormones:  1. Proteins/peptides-water soluble.  2. Amines-water soluble.  3. Steroids-not water soluble.

33. Key Events  There are 3 key events involved in signaling:  1. Reception-is when the signal binds to the receptor protein in or on the target cell.  Receptors can be inside or outside the cell.  2. Signal transduction-signal binds and triggers events within the cell (cascade events).  3. Response-changes a cell’s behavior.  There are 3 key events involved in signaling:  1. Reception-is when the signal binds to the receptor protein in or on the target cell.  Receptors can be inside or outside the cell.  2. Signal transduction-signal binds and triggers events within the cell (cascade events).  3. Response-changes a cell’s behavior.

34. Signal Transduction  Receptors for most water soluble proteins are embedded in the plasma membrane.  Binding of a hormone initiates a signal transduction pathway.  Receptors for most water soluble proteins are embedded in the plasma membrane.  Binding of a hormone initiates a signal transduction pathway.

35. Signal Transduction  The pathway is a series of changes where cellular proteins convert an extracellular chemical signal into an intracellular response.  Examples:  Activation of an enzyme  Uptake or secretion of a specific molecule  Rearrangement of a cytoskeleton  The pathway is a series of changes where cellular proteins convert an extracellular chemical signal into an intracellular response.  Examples:  Activation of an enzyme  Uptake or secretion of a specific molecule  Rearrangement of a cytoskeleton

36. Signal Transduction  The signals can activate proteins that can act to directly or indirectly regulate transcription of certain genes.  Hormones can cause a variety of responses in target cells with different receptors.  These responses are types of signal transductions.  The signals can activate proteins that can act to directly or indirectly regulate transcription of certain genes.  Hormones can cause a variety of responses in target cells with different receptors.  These responses are types of signal transductions.

38. Water Soluble Hormones  Most water soluble hormones have receptors embedded in the membrane.  Surface receptor proteins activate proteins in the cytoplasm which then move into the nucleus and regulate transcription.  Most water soluble hormones have receptors embedded in the membrane.  Surface receptor proteins activate proteins in the cytoplasm which then move into the nucleus and regulate transcription.

39. Epinephrine Example- Water Soluble Hormone  Liver cells and smooth muscle of blood vessels supplying skeletal muscle contain -type epinephrine receptors.

40. Epinephrine Example- Water Soluble Hormone  Smooth muscle of intestinal blood vessels contain - type receptors.  The tissues respond differently to epinephrine.  Increased blood flow and glucose to the skeletal muscles.  Decreased blood flow to the digestive tract.  Smooth muscle of intestinal blood vessels contain - type receptors.  The tissues respond differently to epinephrine.  Increased blood flow and glucose to the skeletal muscles.  Decreased blood flow to the digestive tract.

41. Lipid Soluble Hormone  Lipid soluble hormones have their receptors located inside of the cell. Either in the cytoplasm or the nucleus.  Entrance of the signal and binding of the signal to the receptor initiates the signal transduction pathway.  Binding to DNA stimulates transcription of genes.  mRNA produced is translated into protein within the cytoplasm.  Lipid soluble hormones have their receptors located inside of the cell. Either in the cytoplasm or the nucleus.  Entrance of the signal and binding of the signal to the receptor initiates the signal transduction pathway.  Binding to DNA stimulates transcription of genes.  mRNA produced is translated into protein within the cytoplasm.

42. Estrogen Example-Lipid Soluble Hormone  Estrogen induces cells within the female bird’s reproductive system to make large amounts of ovalbumin.

43. Paracrine Signaling  Neighboring cells signal local regulators to convey signals between these neighboring cells.  Neurotransmitters, cytokines, and growth factors are all examples of local regulators.  Neighboring cells signal local regulators to convey signals between these neighboring cells.  Neurotransmitters, cytokines, and growth factors are all examples of local regulators.

44. Paracrine Signaling- Example  Nitric oxide (NO).  When blood O 2 levels fall, endothelial cells in the blood vessel walls synthesize and release NO.  NO activates an enzyme that relaxes neighboring smooth muscle.  This results in the dilation of blood vessels and improves blood flow.  Nitric oxide (NO).  When blood O 2 levels fall, endothelial cells in the blood vessel walls synthesize and release NO.  NO activates an enzyme that relaxes neighboring smooth muscle.  This results in the dilation of blood vessels and improves blood flow.

45. Endocrine Control  The hypothalamus integrates the vertebrates’ nervous and endocrine systems.  It is found on the underside of the brain.  It receives information from nerves throughout the body and brain.  It initiates the appropriate endocrine signals for varying conditions.  The hypothalamus integrates the vertebrates’ nervous and endocrine systems.  It is found on the underside of the brain.  It receives information from nerves throughout the body and brain.  It initiates the appropriate endocrine signals for varying conditions.

46. The Hypothalamus  Contains 2 sets of neurosecretory cells.  The secretions from these cells are stored in or regulate the activity of the pituitary gland.  Contains 2 sets of neurosecretory cells.  The secretions from these cells are stored in or regulate the activity of the pituitary gland.

47. The Pituitary  The pituitary gland has 2 parts: the anterior and the posterior.

48. The Anterior Pituitary Gland  It is regulated by hormones produced by neurosecretory cells in the hypothalamus.  Some inhibit hormone release, others stimulate it.  The adenohypophysis consists of endocrince cells that make and secrete at least 6 different hormones.  Many of them target and stimulate endocrine glands.  It is regulated by hormones produced by neurosecretory cells in the hypothalamus.  Some inhibit hormone release, others stimulate it.  The adenohypophysis consists of endocrince cells that make and secrete at least 6 different hormones.  Many of them target and stimulate endocrine glands.

49. The Anterior Pituitary Gland  FSH-stimulates production of ova and sperm.  LH-stimulates ovaries and testes.  TSH-stimulates the thyroid gland.  ACTH-stimulates production and secretion of the hormones of the adrenal cortex.  MSH-stimulates concentration of melanin in skin.  Prolactin-stimulates mammary gland growth and milk synthesis.  FSH-stimulates production of ova and sperm.  LH-stimulates ovaries and testes.  TSH-stimulates the thyroid gland.  ACTH-stimulates production and secretion of the hormones of the adrenal cortex.  MSH-stimulates concentration of melanin in skin.  Prolactin-stimulates mammary gland growth and milk synthesis.

50. The Posterior Pituitary Gland  The neurohypophysis is an extension of the hypothalamus.  It stores and secretes 2 hormones: ADH and oxytocin.  ADH acts on the kidneys increasing H 2 O retention.  Oxytocin signals uterine muscle contraction and mammary gland excretion of milk.  The neurohypophysis is an extension of the hypothalamus.  It stores and secretes 2 hormones: ADH and oxytocin.  ADH acts on the kidneys increasing H 2 O retention.  Oxytocin signals uterine muscle contraction and mammary gland excretion of milk.

51. The Thyroid Gland  The thyroid produces 2 hormones.  Triiodothyroxine (T3)  Thyroxin (T4)  In mammals, T4 is converted to T3 by target cells.  T3 is mostly responsible for the cellular response.  The thyroid produces 2 hormones.  Triiodothyroxine (T3)  Thyroxin (T4)  In mammals, T4 is converted to T3 by target cells.  T3 is mostly responsible for the cellular response.

52. The Thyroid Gland  The thyroid is crucial to development.  It is required for normal functioning of bone-forming cells.  It promotes branching of nerves in utero.  It helps skeletal growth and mental development.  It helps maintain muscle tone, digestion, reproductive functions, b.p., h.r.  The thyroid is crucial to development.  It is required for normal functioning of bone-forming cells.  It promotes branching of nerves in utero.  It helps skeletal growth and mental development.  It helps maintain muscle tone, digestion, reproductive functions, b.p., h.r.

53. The Thyroid Gland  The thyroid creates calcitonin.  It works in conjunction with the parathyroid to maintain calcium homeostasis.  The thyroid creates calcitonin.  It works in conjunction with the parathyroid to maintain calcium homeostasis.

54. Parathyroid Hormone  Released by the parathyroid gland in response to low blood calcium levels.  PTH induces the breakdown of osteoclasts.  Ca 2+ is then released into the blood.  PTH stimulates Ca 2+ uptake by the renal tubules.  Released by the parathyroid gland in response to low blood calcium levels.  PTH induces the breakdown of osteoclasts.  Ca 2+ is then released into the blood.  PTH stimulates Ca 2+ uptake by the renal tubules.

55. Parathyroid Hormone  PTH also promotes the conversion of vitamin D into its active form.  The active form of vitamin D acts on the intestines stimulating the uptake of Ca 2+ from food.  When Ca 2+ gets above a certain setpoint, it promotes the release of calcitonin which opposes the effects of PTH lowering blood Ca 2+ levels.  PTH also promotes the conversion of vitamin D into its active form.  The active form of vitamin D acts on the intestines stimulating the uptake of Ca 2+ from food.  When Ca 2+ gets above a certain setpoint, it promotes the release of calcitonin which opposes the effects of PTH lowering blood Ca 2+ levels.

56. Homeostasis  Homeostatic mechanisms moderate changes in internal environments and have 3 functional components:  1. A receptor  2. A control center  3. An effector  Homeostatic mechanisms moderate changes in internal environments and have 3 functional components:  1. A receptor  2. A control center  3. An effector

57. The Receptor  Detects a change in the internal environment of an animal.  Example: Body temperature.  Detects a change in the internal environment of an animal.  Example: Body temperature.

58. The Control Center  Processes the information it receives and directs an appropriate response.  Example: Brain.  Processes the information it receives and directs an appropriate response.  Example: Brain.

59. The Effector  The effector displays the appropriate response.  Example: Shivering, dilation or constriction of blood vessels.  The effector displays the appropriate response.  Example: Shivering, dilation or constriction of blood vessels.

60. For Example:  The regulation of room temperature.  The control center is the thermostat and it contains a receptor called the thermometer.  When the temp falls below a set point, it switches the heater (the effector) on.  When the thermometer senses the temp is above the set point, it switches the heat off-- negative feedback.  The regulation of room temperature.  The control center is the thermostat and it contains a receptor called the thermometer.  When the temp falls below a set point, it switches the heater (the effector) on.  When the thermometer senses the temp is above the set point, it switches the heat off-- negative feedback.

61. Negative Feedback  Occurs when the variable being monitored counteracts any further change in the same direction.  There are only slight variations above and below the set point in a negative feedback system.  Most homeostatic mechanisms in an animal operate under this principle.  Occurs when the variable being monitored counteracts any further change in the same direction.  There are only slight variations above and below the set point in a negative feedback system.  Most homeostatic mechanisms in an animal operate under this principle.

62. Positive Feedback  On the other hand, positive feedback occurs when a change in an environmental variable triggers mechanisms that amplify the change.  For example:  During childbirth, the head against the uterine wall stimulates more contractions in the uterus.  Positive feedback completes childbirth.  On the other hand, positive feedback occurs when a change in an environmental variable triggers mechanisms that amplify the change.  For example:  During childbirth, the head against the uterine wall stimulates more contractions in the uterus.  Positive feedback completes childbirth.

63. Thermoregulation  This is the process by which animals maintain an internal temperature within a tolerable range.  This ability is critical to survival because enzyme function and membrane permeability is dramatically affected by large changes in temperature.  This is the process by which animals maintain an internal temperature within a tolerable range.  This ability is critical to survival because enzyme function and membrane permeability is dramatically affected by large changes in temperature.

64. Heat Exchange  Endotherms and ectotherms use 4 modes of heat exchange:  1. Conduction  2. Convection  3. Radiation  4. Evaporation  Endotherms and ectotherms use 4 modes of heat exchange:  1. Conduction  2. Convection  3. Radiation  4. Evaporation

65. Thermoregulatory Functions  Thermoregulators function by balancing heat loss with heat gain.  There are 5 general categories to assist with this:  1. Insulation  2. Circulatory Adaptation  3. Evaporative Cooling  4. Behavioral Responses  5. Adjusting Metabolism  Thermoregulators function by balancing heat loss with heat gain.  There are 5 general categories to assist with this:  1. Insulation  2. Circulatory Adaptation  3. Evaporative Cooling  4. Behavioral Responses  5. Adjusting Metabolism

66. 1. Insulation  Fat, hair, and/or feathers help to reduce heat flow between the organism and the surroundings.  The integumentary system in mammals acts as this insulating layer.  Fat, hair, and/or feathers help to reduce heat flow between the organism and the surroundings.  The integumentary system in mammals acts as this insulating layer.

67. 2. Circulatory Adaptations  Vasodilation and vasoconstriction work together to transfer body heat form the core to the surroundings.  Vasodilation--vessels get larger.  Vasoconstriciton--vessels get smaller.  Vasodilation and vasoconstriction work together to transfer body heat form the core to the surroundings.  Vasodilation--vessels get larger.  Vasoconstriciton--vessels get smaller.

68. 3. Evaporative Cooling  Many animals have structural adaptations that enable them to take advantage of evaporation as a way of controlling body temperature.  For Example: Sweat glands, panting, and mucous secretions.  Many animals have structural adaptations that enable them to take advantage of evaporation as a way of controlling body temperature.  For Example: Sweat glands, panting, and mucous secretions.

69. 4. Behavioral Adaptations  Behavioral responses are used by endotherms and ectotherms as a means to control body temperature.  Basking in the sun  Migration  Hibernation  Behavioral responses are used by endotherms and ectotherms as a means to control body temperature.  Basking in the sun  Migration  Hibernation

70. 5. Adjusting Metabolism  There are a variety of ways by which animals can control their body temperature by changing their metabolic activity.  In some mammals, hormones can stimulate mitochondria to generate heat instead of ATP-- non-shivering thermogenesis.  There are a variety of ways by which animals can control their body temperature by changing their metabolic activity.  In some mammals, hormones can stimulate mitochondria to generate heat instead of ATP-- non-shivering thermogenesis.

71. 5. Adjusting Metabolism  In other mammals, a layer of brown fat is found in the neck region and is specialized in rapid heat production.  Some female pythons can increase their body temperature when incubating eggs.  In other mammals, a layer of brown fat is found in the neck region and is specialized in rapid heat production.  Some female pythons can increase their body temperature when incubating eggs.

72. 5. Adjusting Metabolism  Humans have nerve cells concentrated in the hypothalamus to control thermoregulation.  These nerve cells are grouped together and function as a thermostat regulating mechanisms that increase or decrease heat loss.  Humans have nerve cells concentrated in the hypothalamus to control thermoregulation.  These nerve cells are grouped together and function as a thermostat regulating mechanisms that increase or decrease heat loss.

74. Pancreas  The pancreas is both an endocrine and a exocrine gland.  Exocrine-releases secretions into ducts.  Endocrine-secretions diffuse into bloodstream.  Islets of Langerhans are scattered throughout the exocrine portion of the pancreas.  The pancreas is both an endocrine and a exocrine gland.  Exocrine-releases secretions into ducts.  Endocrine-secretions diffuse into bloodstream.  Islets of Langerhans are scattered throughout the exocrine portion of the pancreas.

75. Pancreas  Each islet contains -cells and - cells.  -cells produce glucagon.  -cells produce insulin.  Insulin and glucagon oppose each other and regulate the concentration of glucose in the blood.  Each islet contains -cells and - cells.  -cells produce glucagon.  -cells produce insulin.  Insulin and glucagon oppose each other and regulate the concentration of glucose in the blood.

76. Blood Glucose  Glucagon gets released when blood glucose falls below a setpoint.  Insulin gets released when blood glucose is elevated.  Insulin stimulates most cells to take up glucose from the blood.  It also acts to slow glycogen breakdown in the liver.  Glucagon gets released when blood glucose falls below a setpoint.  Insulin gets released when blood glucose is elevated.  Insulin stimulates most cells to take up glucose from the blood.  It also acts to slow glycogen breakdown in the liver.

77. Diabetes Mellitus  Diabetes is an endocrine disorder caused by a deficiency in insulin or decreased response to insulin.  There are 2 types:  Type I-insulin dependent.  Type II-non-insulin dependent.  Diabetes is an endocrine disorder caused by a deficiency in insulin or decreased response to insulin.  There are 2 types:  Type I-insulin dependent.  Type II-non-insulin dependent.

78. Type I Diabetes  Insulin dependent. It’s an autoimmune disease resulting in the destruction of the body’s - cells.  The pancreas can’t produce insulin and the person requires insulin injections.  Insulin dependent. It’s an autoimmune disease resulting in the destruction of the body’s - cells.  The pancreas can’t produce insulin and the person requires insulin injections.

79. Type II Diabetes  Non-insulin dependent.  It is caused by a reduced responsiveness of the cells to insulin.  Non-insulin dependent.  It is caused by a reduced responsiveness of the cells to insulin.