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Description
Flashcards by megan.radcliffe16, updated more than 1 year ago
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Created by megan.radcliffe16
over 9 years ago
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| Question | Answer |
| Define Endocrine gland. | A gland that secrets hormones directly into the blood. Endocrine glands have no ducts. |
| Define Exocrine gland. | A gland that secrets molecules directly into a duct that carries the molecules to where they are used |
| Define Hormone. | A molecule released into the blood which acts as a chemical messenger |
| Define Target Tissue. | A group of cells that have receptors embedded in the plasma membrane that are complementary in shape to specific hormone molecules. |
| What is a first messenger? What is an example? | A hormone that transmits a message around the body. Adrenaline. |
| What is a second messenger? What is an example? | It transmits a signal inside the cell. cAMP |
| What are the two regions of the adrenal gland? | Adrenal medulla Adrenal cortex |
| What does the Adrenal Medulla do? | It releases adrenaline. |
| What is the effect that adrenaline have on the body? | • Relaxes smooth muscle in the bronchioles • Increases the stroke volume of the heart • Increases heart rate • Stimulates conversion of glycogen to glucose • Dilates the pupils • Increases mental awareness • Inhibits the action of the gut • Causes body hair to erect |
| What does the adrenal Cortex do? | Releases cholesterol |
| what is cholesterol used for in the body? | It is used to make steroid hormones in the body. |
| What is the role of the pancreas as an exocrine and endocrine gland? | The cells surrounding the exocrine gland of the pancreas secretes digestive enzymes into the pancreatic duct. The endocrine cells- the Islets of Langerhans- consist of α and β cells. |
| What is the function of the α cells in the islets of Langerhans? | To manufacture and release glucagon directly into the blood. |
| What is the function of the β cells in the Islets of Langerhans? | To manufacture and release insulin |
| What is the effect of glucagon on the blood glucose levels? | It increases the glucose concentration in the blood |
| What is the effect of insulin on the blood glucose levels? | It decreases the glucose concentration in the blood |
| What happens if the blood glucose levels drop too low? | • Detected by α cells • The fall inhibits insulin production • They secrete glucagon into the blood • Bind to receptors on hepatocytes o Glycogenolysis- conversion of glycogen to glucose o More fatty acids are used in respiration o Gluconesgenesis- conversion of amino acids and fats to glucose • More glucose in the bloodstream |
| What happens if the blood glucose levels become too high? | Detected by β cells • The rise inhibits glucagon production • Secrete insulin into the blood • Bind to receptors on hepatocytes, in the liver • This activates adenyl cyclase in the cell • Converts ATP to cAMP |
| When cAMP is produced what type reactions take place within the cell? | 1. More glucose channels are places in the cell surface membrane 2. More glucose enters the cell 3. Glycogenesis- glucose in the cell is converted to glycogen 4. More glucose is converted to fats 5. More glucose is used in respiration |
| How is insulin secretion controlled with the potassium and calium channels in the beta cells? | 1. The cell membranes of the β cells contain Ca2+ and K+ ion channels. 2. K ions diffuse out of the cell, making the inside more negative. 3. When glucose concentrations outside of the cells are high, glucose molecules diffuse into the cell. 4. The glucose is quickly metabolised to ATP. 5. The extra ATP cause the K ion channels to close. 6. The K ions can no longer diffuse out, so the cells become less negative inside. 7. This change in potential difference opens the Ca ion channels. 8. Ca2+ ions enter the cell. 9. Secretion of insulin occurs as the vesicles containing insulin move to the cell surface membrane and fuse with it. 10. This releases insulin by exocytosis |
| What are the features of type 1 diabetes? | 1. uncontrolled blood glucose 2. Insulin-dependent 3. usually juvenile onset 4.treated by insulin injections and careful diet and exercise. |
| What causes type 1 diabetes? | The inactive beta cells May be caused by an autoimmune response or a virus. |
| What are the features of type 2 diabetes? | 1. uncontrolled blood glucose levels 2. Non insulin dependent 3. middle age onset 4. treatment by careful diet and exercise |
| What causes type 2 diabetes? | Liver cells become less responsive to insulin. Linked to obesity, high levels of refined sugar in diet and family history. |
| Why can GM bacteria be used to produce insulin? | • Exact copy of human insulin. o Faster acting. o More effective. • Less chance of developing tolerance. • Less chance of rejection. • Cheaper. • More adaptable to demand. • Less likely to have moral objections. |
| How can stem cells be used to treat diabetes? | • Could be used to produce new β cells. • Undifferentiated. |
| What is diabetes mellitus? | the inability to control blood glucose concentration. |
| What is the heart rate controlled by? | Hormonal and nervous mechanisms |
| What does the SAN do? | It initiates waves of contraction that cause the heart to beat. |
| what two nerves is the SAN affected by? | The vagus nerve The Accelerator nerve |
| What does the vagus nerve do? | It releases acetylcoline which reduces the heart rate. |
| What does teh accelerator nerve do? | It releases noradrenaline which increases the heart rate. |
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