Bio 30 review chapter 13: Hormones
When the brain detects danger, it directs the hypothalamus to secrete a releasing hormone. The releasing hormone stimulates the anterior pituitary gland to secrete adrenocorticotropic hormone (ACTH). ACTH targets the adrenal cortex, which causes the release of the stress hormone cortisol.
ACTH
Cell of the pancreas which secretes glucagon to increase the level of blood glucose
Alpha cell
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At what point is the negative feedback loop disrupted when one develops hyperthyroidism? Hypothyroidism?
In 1921, a research team from the University of Toronto, Ontario, led by Frederick Banting and his assistant Charles Best made a breakthrough. By tying off a dog's pancreatic duct with some string, they were able to remove some islets of Langerhans from the dog's pancreas, and then isolate insulin from the islets. Banting and his research team soon found a way to isolate insulin from the pancreases of embryonic calves, which were a by-product of the beef industry. Working with a biochemist from the University of Alberta, J.B. Collip, they further purified the extracted insulin and used it to successfully treat a boy with diabetes.
Banting and Best
Cell of the pancreas which secretes insulin to decrease the level of blood glucose
Beta cell
These hormones regulate a short-term stress response that is commonly referred to as the fight-or- flight response. The effects of these hormones on the body are similar to those caused by stimulation of the sympathetic nervous system.
Describe the hormonal and nervous system interactions in the stress response.
Endocrine glands are ductless glands i.e;they release their secretions directly into blood stream.
Endocrine glands
-lowers blood glucose level. - cause excess glucose to be converted into fat. - increases permeability of cell membranes to glucose. - results in the conversion of glucose to glycogen in the liver.
Functions of insulin
Calcium levels in the blood are regulated, in part, by a hormone called calcitonin. When the concentration of calcium in the blood rises too high, calcitonin stimulates the uptake of calcium into bones, which lowers its concentration in the blood. The role of calcitonin in regulating blood calcium levels is significant in some vertebrates such as fish and rodents. In humans, on the other hand, calcitonin appears to play a minor regulatory role. A different hormone, secreted by the parathyroid glands, plays a much more significant role in calcium homeostasis.
How are calcium levels in the blood regulated?
-insulin lowers blood glucose levels and promotes the formation of glycogen in the liver. -glucagon raises blood glucose levels by converting glycogen to glucose.
How do levels of insulin and glucagon regulate levels of blood glucose
Cortisol triggers the metabolism of proteins and fats to produce glucose. Cortisol also suppresses the immune system, which is probably one reason that chronic stress is unhealthy.
How does cortisol affect the immune system?
If the beta cells are destroyed, type 1 diabetes results. Type 2 diabetes develops when the insulin receptors on the cells do not respond properly to insulin.
How does diabetes occur?
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How does the nervous system and the endocrine system act together to regulate the stress response?
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How is a goiter developed? At what point is the negative feedback loop interrupted?
Many hormones are regulated by negative feedback mechanisms, or loops. When a certain blood concentration of hormone is reached, or when target cells have responded to a specific hormone, the endocrine gland releasing the hormone is inhibited. Thus, the release of the hormone slows.
How is hormone secretion regulated?
cluster of endocrine cells found throughout the pancreas, consisting of glucagon producing alpha cells and insulin- producing beta cells.
Islet of langerhans
hormone that targets endocrine glands and stimulates them to release other hormones.
Tropic hormone
A condition in which the immune system produces antibodies that attack and destroy the beta cells of the pancreas so they are unable to produce insulin; is usually diagnosed in childhood, and patients require daily insulin injections. AKA juvenile diabetes, AKA insulin-dependent diabetes
Type 1 diabetes
a condition that develops slowly over time either because the insulin receptors on the body's cells stop responding to insulin receptors on the beta cells stop responding to insulin or because the beta cells of the pancreas produce less and less insulin over time; condition often appears in overweight adults. AKA adult-onset diabetes, AKA non-insulin-dependent diabetes.
Type 2 diabetes
The human body has two adrenal glands, which are located on top of the kidneys. Each gland is composed of an inner layer (the adrenal medulla) and an outer layer (the adrenal cortex).
What are the 2 adrenal glands and where are they located?
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What are the physiological effects of diabetes mellitus?
The parathyroid glands are four small glands attached to the thyroid. The parathyroid glands produce a hormone called parathyroid hormone (PTH). The body synthesizes and releases PTH in response to falling concentrations of calcium in the blood. PTH stimulates bone cells to break down bone material (calcium phosphate) and reabsorb calcium into the blood. PTH also stimulates the kidneys to reabsorb calcium from the urine, activating vitamin D in the process. Vitamin D, in turn, stimulates the absorption of calcium from food in the intestine. These effects bring the concentration of calcium in the blood back within a normal range so that the parathyroid glands no longer secrete PTH.
What do parathyroid glands do for calcium homeostasis?
The two major hormones that the pancreas produces are glucagon and insulin. Insulin causes the liver to take the glucose in your blood and turn it into glycogen. Insulin is released when your blood sugar levels are too high for homeostasis to occur.
What does the pancreas do for maintaining homeostasis?
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What is the effect of Aldosterone on the human body during the long term stress response?
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What is the effect of cortisol on the human body during the long term stress response?
-Thyroxine (T4) is required for healthy mentalandphysicaldevelopment during childhood, and an active metabolism throughout life. Thyroxine containsiodine,andthuspeople require iodine in the diet. -Thyroxine secretion is regulated by the release of thyroid-stimulating hormone (TSH) from the anterior pituitary. TSH is regulated by negative feedback by thyroxine on the hypothalamus and pituitary.
What is the primary effect of thyroxine? What kind of cells does thyroxine stimulate?
anterior lobe of the pituitary gland; an endocrine gland that synthesizes and secretes six major hormones: human growth hormone (hGH), prolactin (PRL), thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), follicle-stimulating hormone (FSH), and leutinizing hormone (LH).
anterior pituitary
exocrine glands are duct glands i.e;these glands are provided with ducts to transport their secretions.Eg:-salivary glands,pancreas.
exocrine glands
hormone produced by the alpha cells of the islets of langerhans in the pancreas to stimulate the liver to convert glycogen back into glucose, which is released into the blood.
glucagon
a substance deposited in bodily tissues as a store of carbohydrates. It is a polysaccharide that forms glucose on hydrolysis.
glycogen
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how do insulin and glucagon help to maintain homeostasis?
The nervous and endocrine systems are self-regulating, and help regulate other body systems, thereby maintaining homeostasis.
how do the endocrine system and the nervous work together to maintain homeostasis?
hGH stimulates the growth of muscles, connective tissue, and the growth plates at the end of the long bones, which causes elongation of these bones. If the pituitary gland secretes excessive amounts of hGH during childhood, it can result in a condition called gigantism. No hGH is not a tropic hormone.
how does hGH contribute to healthy growth and development? Is it a tropic hormone
Condition resulting from high levels of blood glucose; occurs in individuals with diabetes mellitus
hyperglycaemia
when your blood glucose (sugar) levels are too low. The symptoms of Addison's disease include hypoglycemia (low blood sugar)
hypoglycaemia
a hormone secreted by the alpha cells of islets of langerhans in the pancreas to make target cells more permeable to glucose; enables the body to use sugar and other carbohydrates.
insulin
mechanism of homeostatic response by which the output of a system surpasses or inhibits activity of the system; e.g.: when a certain blood concentration of a hormone is reached, the endocrine gland releasing the hormone is inhibited by the presence of the hormone.
negative feedback mechanism
posterior lobe of the pituitary gland; an endocrine gland that stores and releases antidiuretic hormone (ADH) and oxytocin, heir are produced in the hypothalamus and transferred to the posterior pituitary by neuronal axons.
posterior pituitary
The thyroid gland secretes hormones that regulate cell metabolism, growth, and development.
purpose and function of the thyroid gland
X-rays and PET scans or other nuclear scanning techniques.
since hormones are small, what technologies are used to study them?
The anterior pituitary and posterior pituitary make up the two lobes of the pituitary gland. Each lobe is really a separate gland, and they release different hormones.
where do you find the posterior and anterior pituitary?
• Some nervous system tissues secrete hormones, such as cells in the hypothalamus, pituitary gland, and adrenal glands. • Several chemicals function as both neurotransmitters and hormones, depending on their location in the body. An example is epinephrine, which acts as a neurotransmitter between certain neurons in the nervous system, and as a hormone released by the adrenal glands in the fight-or-flight response. • The endocrine and nervous systems both include responses that are regulated by negative feedback loops. • The regulation of several physiological processes involves both the nervous and endocrine systems acting in conjunction with each other.
why is the distinction between the endocrine system and the nervous systems arbitrary?