Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Found at: the base of the throat Consists of: two lobes and a connecting isthmus Produces two hormones 1. Thyroid hormone 2. Calcitonin Thyroid Gland 1. Thyroid hormone Major metabolic hormone Composed of two active iodine- containing hormones Thyroxine (T4)—secreted by thyroid follicles Triiodothyronine (T3)—conversion of T4 at target tissues Thyroid Gland Thyroid Hormone Disorders Goiters Thyroid gland enlarges In U.S., rarely see goiters due to lack of iodine because we use “iodized” salt Goiters Thyroid Hormone Disorders Cretinism Caused by hyposecretion of thyroxine Lack of iodine Congenital lack of thyroid gland Results in stunted physical and mental growth during childhood Cretinism Thyroid Hormone Disorders Myxedema Caused by hypothyroidism in adults Results in physical and mental slugishness Myxedema Thyroid Hormone Disorders Grave’s Disease Caused by hyperthyroidism Results in: increased metabolism heat intolerance rapid heartbeat weight loss exophthalmos Exophthalmos Thyroid Gland 2. Calcitonin Decreases blood calcium levels by causing its deposition on bone Antagonistic to parathyroid hormone Produced by parafollicular cells Parathyroid Gland Tiny masses (4) on the posterior of the thyroid Parathyroid Gland Secrete parathyroid hormone (PTH) Raise calcium levels in the blood 1. Stimulate osteoclasts to remove calcium from bone 2. Stimulate the kidneys and intestine to absorb more calcium Rising blood Ca2+ levels Calcium homeostasis of blood 9–11 mg/100 ml Thyroid gland Rising blood Ca2+ levels Calcium homeostasis of blood 9–11 mg/100 ml Calcitonin Thyroid gland releases calcitonin Thyroid gland Rising blood Ca2+ levels Calcium homeostasis of blood 9–11 mg/100 ml Calcitonin Thyroid gland releases calcitonin Thyroid gland Rising blood Ca2+ levels Calcium homeostasis of blood 9–11 mg/100 ml Calcitonin stimulates calcium salt deposit in bone Calcitonin Thyroid gland releases calcitonin Thyroid gland Rising blood Ca2+ levels Calcium homeostasis of blood 9–11 mg/100 ml Calcitonin stimulates calcium salt deposit in bone Calcium homeostasis of blood 9–11 mg/100 ml Falling blood Ca2+ levels Calcium homeostasis of blood 9–11 mg/100 ml Thyroid gland Parathyroid glands Falling blood Ca2+ levels Calcium homeostasis of blood 9–11 mg/100 ml Falling blood Ca2+ levels Thyroid gland Parathyroid glands PTH Parathyroid glands release parathyroid hormone (PTH) Calcium homeostasis of blood 9–11 mg/100 ml Falling blood Ca2+ levels Thyroid gland Parathyroid glands Osteoclasts degrade bone matrix and release Ca2+ into blood PTH Parathyroid glands release parathyroid hormone (PTH) Calcium homeostasis of blood 9–11 mg/100 ml Thyroid gland Parathyroid glands Osteoclasts degrade bone matrix and release Ca2+ into blood PTH Parathyroid glands release parathyroid hormone (PTH) Calcium Homeostasis Adrenal Glands Sit on top of the kidneys Two regions 1. Adrenal cortex—outer glandular region has three layers A. Mineralocorticoids secreting area B. Glucocorticoids secreting area C. Sex hormones secreting area 2. Adrenal medulla—inner neural tissue region. When stimulated, it releases EPINEPHRINE and NOREPINEPHRINE Adrenal Cortex Adrenal Cortex Mineralocorticoid layer secretes ALDOSTERONE Aldosterone is important for sodium (Na+) and potassium (K+) balance; works on kidneys Glucocorticoid layer secretes CORTISOL and CORTISONE Help resist long-term stressors Released in response to increased blood levels of ACTH Sex hormone layer secretes small amount of ANDROGENS and ESTROGENS Short term Stress Hypothalamus Short term Stress Hypothalamus Nerve impulses Spinal cord Short term Stress Hypothalamus Nerve impulses Spinal cord Preganglionic sympathetic fibers Adrenal medulla Short term Stress Hypothalamus Nerve impulses Spinal cord Preganglionic sympathetic fibers Adrenal medulla Catecholamines (epinephrine and norepinephrine) Short-term stress response Stress Hypothalamus More prolonged Stress More prolonged Hypothalamus Releasing hormone Corticotropic cells of anterior pituitary ACTH Adrenal cortex More prolonged Stress Hypothalamus Releasing hormone Corticotropic cells of anterior pituitary ACTH Mineralocorticoids Adrenal cortex Glucocorticoids Long-term stress response Adrenal cortex disorders Addison’s disease Results from hyposecretion of all adrenal cortex hormones Bronze skin tone, muscles are weak, burnout, susceptibility to infection Adrenal cortex disorders Adrenal cortex disorders Cushing’s syndrome Results from a tumor in the middle cortical area of the adrenal cortex Characterized by: “Moon face” “Buffalo hump” on the upper back High blood pressure Increased blood sugar Depression Cushing’s Syndrome Pancreas The pancreas is a mixed gland and has both endocrine and exocrine functions Pancreatic Islets: 2 Hormones 1. Insulin (beta cells): allows glucose to cross plasma membranes into cells 2. Glucagon (alpha cells): allows glucose stored in cells to be released into the blood Homeostasis: Normal blood glucose levels (90 mg/100ml) Stimulus: rising blood glucose levels (e.g., after eating four jelly doughnuts) Homeostasis: Normal blood glucose levels (90 mg/100ml) Elevated blood sugar levels Stimulus: rising blood glucose levels (e.g., after eating four jelly doughnuts) Homeostasis: Normal blood glucose levels (90 mg/100ml) Insulin-secreting cells of the pancreas activated; release insulin into the blood Elevated blood sugar levels Stimulus: rising blood glucose levels (e.g., after eating four jelly doughnuts) Homeostasis: Normal blood glucose levels (90 mg/100ml) Insulin-secreting cells of the pancreas activated; release insulin into the blood Uptake of glucose from blood is enhanced in most body cells Elevated blood sugar levels Stimulus: rising blood glucose levels (e.g., after eating four jelly doughnuts) Homeostasis: Normal blood glucose levels (90 mg/100ml) Insulin-secreting cells of the pancreas activated; release insulin into the blood Elevated blood sugar levels Stimulus: rising blood glucose levels (e.g., after eating four jelly doughnuts) Uptake of glucose from blood is enhanced in most body cells Liver takes up glucose and stores it as glycogen Homeostasis: Normal blood glucose levels (90 mg/100ml) Insulin-secreting cells of the pancreas activated; release insulin into the blood Elevated blood sugar levels Stimulus: rising blood glucose levels (e.g., after eating four jelly doughnuts) Uptake of glucose from blood is enhanced in most body cells Liver takes up glucose and stores it as glycogen Homeostasis: Normal blood glucose levels (90 mg/100ml) Blood glucose levels decline to set point; stimulus for insulin release diminishes Homeostasis: Normal blood glucose levels (90 mg/100ml) Stimulus: declining blood glucose levels (e.g., after skipping a meal) Homeostasis: Normal blood glucose levels (90 mg/100ml) Stimulus: declining blood glucose levels (e.g., after skipping a meal) Low blood sugar levels Homeostasis: Normal blood glucose levels (90 mg/100ml) Stimulus: declining blood glucose levels (e.g., after skipping a meal) Low blood sugar levels Glucagon-releasing cells of pancreas activated; release glucagon into blood; target is the liver Homeostasis: Normal blood glucose levels (90 mg/100ml) Stimulus: declining blood glucose levels (e.g., after skipping a meal) Low blood sugar levels Liver breaks down glycogen stores and releases glucose to the blood Glucagon-releasing cells of pancreas activated; release glucagon into blood; target is the liver Homeostasis: Normal blood glucose levels (90 mg/100ml) Stimulus: declining blood glucose levels (e.g., after skipping a meal) Low blood sugar levels Rising blood glucose levels return blood sugar to homeostatic set point; stimulus for glucagon release diminishes Liver breaks down glycogen stores and releases glucose to the blood Glucagon-releasing cells of pancreas activated; release glucagon into blood; target is the liver Pineal Gland Found on the third ventricle of the brain Pineal Gland Called the “third eye” because it receives visual information from the retina regarding light and dark Secretes melatonin Helps establish the body’s wake and sleep cycles