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7 Cards in this Set
- Front
- Back
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Define endocrine, exocrine and hormone. |
Hormone = chemical messenger. Endocrine = ductless gland that releases hormones directly into blood. Exocrine = released molecules (and other substances) into a gland or a duct. |
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Why is the pancreas described as having both endocrine and exocrine function? |
Endocrine = releases hormones insulin and glucagon directly into blood from alpha and beta cells in the Islets of Langerhan. Exocrine = releases pancreatic juices (e.g enzyme amylase) into pancreatic duct to be carried towards intestine. |
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State difference between Type 1 and Type 2 Diabetes? |
Type 1: juvenile onset. Cannot produce insulin - autoimmune response. Needs insulin injection. Type 2: late onset. Cells do not respond to insulin. Due to poor diet and lack of exercise. Insulin still present in blood but ineffective. |
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How is high blood glucose regulated? |
Islets of Langerhans contains alpha and beta cells. Beta cells release hormone insulin directly into blood. Insulin travels around blood and binds to receptors on the membrane of the target cell (liver or muscle). Insulin causes target cells to absorb glucose from blood and convert glucose into glycogen - glycogenesis. |
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How is low blood glucose regulated. |
Alpha cells in Islets of Langerhan secret Glucagon directly into blood. Glucagon travels blood and binds to complementary receptors on membrane of target cell (liver or muscle). Thus causing glycogen to be broken down into glucose - glycolysis. And causes target cells to make glucose from amino acids - glyconeogenesis. |
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Describe function of adrenal glands. |
Medulla - secrets peptide hormones (adrenaline) directly into blood. Cortex - secrets steroid hormones (cortisol) into...... |
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How is insulin secreted? |
1) K+ channels are open to maintain cell resting potential -70mV. 2) Glucose diffuses in and in metabolised producing ATP. 3)K+ channels are sensitive to ATP therefore they close. 4) Cell potential rises from -70mV to +30mV because of build up of K+ ions. 5) Increase in membrane potential causes Ca+ channels to open. 6) Influx of Ca+ causes vesicles containing Insulin to move towards and fuse with the membrane and release Insulin via exocytosis. |
