10 Questions
What is the definition of a hormone, according to the text?
A chemical substance produced in minute quantities by an endocrine gland, transported by the bloodstream to a target organ.
What is the function of the islets of Langerhans in the pancreas?
To produce hormones such as insulin and glucagon that regulate blood glucose concentration.
How do insulin and glucagon regulate blood glucose concentration?
Insulin lowers blood glucose concentration, while glucagon raises it.
What is type 2 diabetes mellitus characterized by?
A persistently higher than normal blood glucose concentration due to insulin resistance or insufficient production.
What is the role of endocrine glands in hormone regulation?
Endocrine glands produce hormones that are transported by the bloodstream to target organs.
What is the effect of insulin resistance on blood glucose levels?
Insulin resistance leads to higher than normal blood glucose levels.
How does the body respond to stress, such as during an O Level examination?
The body responds with increased heart rate, perspiration, and other physiological changes.
What is the importance of hormones in the body?
Hormones regulate various physiological processes, such as glucose metabolism and stress response.
What is the function of the pancreas in glucose metabolism?
The pancreas produces insulin and glucagon to regulate blood glucose concentration.
What is the relationship between unhealthy diet and sedentary lifestyle, and the risk of type 2 diabetes mellitus?
Unhealthy diet and sedentary lifestyle increase the risk of type 2 diabetes mellitus.
Study Notes
Types of Glands
- There are two types of glands in the body: endocrine glands and exocrine glands
- Endocrine glands are ductless and transport their secretions through the bloodstream
- Examples of endocrine glands: pituitary gland, adrenal gland, and pancreas
- Exocrine glands have ducts that transport secretions to target organs
- Examples of exocrine glands: sweat gland, salivary gland, and pancreas (which has both endocrine and exocrine functions)
Endocrine Glands and Their Hormonal Secretions
- The pituitary gland is referred to as the 'master gland' and secretes many hormones that control the secretion of other hormones
- The pituitary gland secretes antidiuretic hormone (ADH)
- The hypothalamus regulates the secretion of some hormones, including those secreted by the pituitary gland
- The pancreas has both endocrine and exocrine glands, with the islet of Langerhans secreting insulin and glucagon to control blood glucose levels
- The pancreas also secretes pancreatic juice through pancreatic ducts
Hormonal Secretions
- Ovaries (in females) secrete estrogen and progesterone
- Testes (in males) secrete testosterone
- Hormones released by the gonads (ovaries and testes) control the development of primary and secondary sexual characteristics, but do not function until puberty
Regulation of Blood Glucose Concentration
- Insulin increases the rate of glucose uptake by cells and makes cell membranes more permeable to glucose, decreasing blood glucose concentration
- Insulin stimulates body cells to increase the utilization of glucose for respiration
- The islets of Langerhans in the pancreas secrete more insulin when the blood glucose concentration is above normal
Definition of Hormones
- A hormone is a chemical substance produced by a gland, carried by the blood, which alters the activity of one or more specific target organs
- Hormones are produced in minute quantities by endocrine glands and are transported by the bloodstream to a target organ, which is the effector
Learn about the two types of glands in the human body, endocrine and exocrine glands, their functions, and examples of each. Discover the role of the pituitary gland and other glands in our body.
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