Bio 202 First Half Of Exam 2

The neurohypophysis, also known as the posterior pituitary, is responsible for secreting oxytocin (OT). Oxytocin is a hormone that plays a crucial role in various physiological processes, such as labor and lactation. It is released in response to stimuli like childbirth or breastfeeding and promotes uterine contractions and milk ejection. Therefore, the statement that the neurohypophysis secretes oxytocin is true.

Growth hormone (GH) has more target cells in the body than any of the others mentioned. GH is produced by the pituitary gland and acts on various tissues and organs throughout the body. It promotes growth and development, regulates metabolism, and has effects on multiple systems including bone, muscle, and fat. In contrast, oxytocin (OT) primarily acts on the reproductive system and is involved in childbirth and lactation. Antidiuretic hormones primarily act on the kidneys to regulate water balance in the body. Therefore, GH has a broader range of target cells and functions compared to the other hormones listed.

A cell becomes a target of a particular hormone when it possesses a receptor for that hormone. Receptors are specific proteins located on the cell membrane or inside the cell that bind to hormones, allowing them to communicate and elicit a response. The presence of a receptor determines whether a cell can respond to a specific hormone or not. Therefore, the correct answer is "the presence of a receptor for that particular hormone."

When a cell decreases the number of receptors to a hormone, it means that there are fewer binding sites available for the hormone to attach to. As a result, the hormone is less likely to bind to the cell and activate its signaling pathways, leading to a decrease in its effects on the cell. This reduction in receptor availability can occur due to various reasons, such as downregulation of receptor expression or internalization of receptors from the cell surface.

Luteinizing hormones are not hypothalamic hormones because they are produced and released by the anterior pituitary gland, not by the hypothalamus. The hypothalamus does play a role in regulating the release of luteinizing hormone through the secretion of gonadotropin-releasing hormone (GnRH), but luteinizing hormone itself is not directly produced by the hypothalamus. Instead, it acts on the gonads (testes in males and ovaries in females) to stimulate the production of sex hormones such as testosterone and estrogen.

The pancreas secretes somatostatin, insulin, glucagon, and pancreatic enzymes. Growth hormone is not secreted by the pancreas.

ACTH --> adrenicorticotropic hormone

LH (luteinizing hormone) is responsible for controlling the production of testosterone in males. It stimulates the Leydig cells in the testes to produce testosterone, which is essential for the development and maintenance of male reproductive organs and characteristics. Therefore, LH plays a crucial role in regulating the levels of testosterone in males.

Aspirin and ibuprofen are both nonsteroidal anti-inflammatory drugs (NSAIDs) that work by inhibiting the action of cyclooxygenase (COX) enzymes. COX enzymes are responsible for the production of prostaglandins, which are inflammatory mediators involved in pain, fever, and inflammation. By blocking the action of COX enzymes, aspirin and ibuprofen reduce the production of prostaglandins, leading to pain relief and anti-inflammatory effects. This is why they are commonly used to treat various conditions such as headaches, muscle aches, and arthritis.

Paracrine hormones are secreted by one cell into the tissue fluid and diffuse to nearby cells in the same tissue, stimulating their physiology. Unlike hormones, which are transported through the bloodstream to target cells in distant tissues, paracrine hormones act locally. Neurotransmitters are chemical messengers that transmit signals across synapses, while cholinesterases are enzymes that break down acetylcholine. Neuromodulators are substances that modulate the activity of neurons but do not directly stimulate nearby cells in the same tissue.

A blow to the head can cause damage to the pituitary gland, which is responsible for producing hormones that regulate various bodily functions. One of the potential consequences of this damage is the development of myxedema, a condition characterized by swelling and thickening of the skin, particularly in the face and hands. Myxedema is typically associated with hypothyroidism, which can occur when the pituitary gland is not functioning properly. Therefore, it is plausible that a blow to the head could lead to myxedema as a result of disrupted hormone production.

After a meal, the alpha cells in the pancreatic islets secrete glucagon. Glucagon is a hormone that raises blood glucose levels. This is important because after a meal, blood glucose levels tend to rise due to the absorption of nutrients from the food. Glucagon acts by stimulating the liver to break down stored glycogen into glucose, which is then released into the bloodstream. This helps to maintain a stable blood glucose level and prevent it from getting too high.

T4 and T3 are monoamine hormones that are mainly transported bound to proteins in the blood. Monoamine hormones are derived from the amino acid tyrosine and include hormones such as adrenaline, noradrenaline, dopamine, and thyroid hormones T4 and T3. These hormones are hydrophobic and therefore require transport proteins to travel through the watery bloodstream. Binding to proteins helps to protect the hormones from degradation, allows for their storage, and controls their release at target tissues.

Acetylcholine is not a catecholamine. Catecholamines are a class of neurotransmitters that include dopamine, norepinephrine, adrenaline, and epinephrine. Acetylcholine, on the other hand, is a different type of neurotransmitter that is not classified as a catecholamine.

The thymus secretes several hormones that stimulate the development of lymphatic organs and regulate the development and activity of T cells. T cells are a type of white blood cell that plays a crucial role in the immune system, so the thymus is important for immune function. The other options listed (spleen, thyroid, parathyroid, adrenal gland) are also involved in various physiological processes, but they do not specifically secrete hormones that stimulate the development of lymphatic organs and regulate T cell activity.

The control of calcium by the parathyroid gland is an example of calcium exhibiting humoral control of parathyroid secretion. Humoral control refers to the regulation of hormone secretion in response to changes in the concentration of certain substances (in this case, calcium) in the blood. The parathyroid gland releases parathyroid hormone (PTH) in response to low levels of calcium in the blood, which then acts to increase calcium levels by stimulating calcium release from bones, increasing calcium absorption from the intestines, and reducing calcium excretion by the kidneys. This control mechanism helps maintain calcium homeostasis in the body.

Glucagon is synthesized in the rough endoplasmic reticulum. The rough endoplasmic reticulum is an organelle involved in protein synthesis and modification. Glucagon is a hormone that is produced by the alpha cells of the pancreas and plays a role in regulating blood sugar levels. The rough endoplasmic reticulum provides the necessary machinery for the synthesis and processing of proteins, including the production of glucagon. Therefore, it is synthesized in the rough endoplasmic reticulum.

Ketone bodies are made by the pancreas and are derived from fatty acids.