travismulthaupt.com Chapter 45 Hormones and the Endocrine System

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.

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

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

 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

What is a nerve?—Form Fitting Function  The synapse is the site of communication between one nerve and another.

What is a nerve?—Form Fitting Function  Neurotransmitters transmit the signal from a pre- synaptic cell to a post-synaptic neuron.

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.

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

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

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.

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.

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.

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

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

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

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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

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.

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.

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

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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

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

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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.