Ch 13 Lecture
What are tropic hormones?
Hormones that stimulate other endocrine glands
Which of the following hormones is released when blood glucose levels are elevated?
Insulin
Which organs are also components of the endocrine system because, in addition to other functions, they produce hormones?
Pineal gland Thymus gland Reproductive organs Digestive tract Heart and kidneys
The hypothalamus uses nervous stimulation to control the secretion of hormones from which gland?
Posterior pituitary
What group of compounds is produced from a specific type of fatty acid and has powerful effects on cells and tissues?
Prostaglandins
What must be present for any type of hormone to be able to act on a target cell?
Protein receptors
Which of the following is true about steroid hormones?
Steroid hormones can diffuse through the lipid bilayer.
Which of the following chemical classification of hormones is derived from cholesterol?
Steroids
What makes a cell a target cell for a hormone?
Target cells have specific receptors for the hormone.
Complete the following sentences describing the endocrine system.
The endocrine system includes cells, tissues, and organs that are collectively called endocrine glands. The glands secrete chemical substances called hormones, which travel in the bloodstream. When these substances reach their target cells, they bind to receptors. The result is a change in the functioning of the cells.
The endocrine system includes glands that secrete substances called
hormones
Which of the following glands is found in the brain?
Pituitary gland
Complete the sentences describing the hormonal control of thyroid hormone release.
Negative feedback occurs when the output of a pathway inhibits input to the pathway. Feedback loops are used extensively to regulate secretion of hormones in the hypothalamic-pituitary axis. An important example of a negative feedback loop is seen in the control of thyroid hormone secretion. The thyroid hormones thyroxine and triiodothyronine (T4 and T3) are synthesized and secreted by thyroid glands and affect metabolism throughout the body. Neurons in the hypothalamus secrete thyroid-releasing hormone (TRH), which stimulates cells in the anterior pituitary to secrete thyroid-stimulating hormone (TSH). TSH binds to receptors in the thyroid gland, stimulating synthesis and secretion of thyroid hormones. When blood concentrations of thyroid hormones increase above a certain threshold, TRH-secreting neurons in the hypothalamus are inhibited and stop secreting TRH. Inhibition of TRH secretion leads to shut-off of TSH secretion, which leads to shut-off of thyroid hormone secretion. As thyroid hormone levels decay below the threshold, negative feedback is relieved. TRH secretion starts again, leading to TSH secretion.
Which gland secretes the antidiuretic hormone (ADH)?
Posterior pituitary
Complete the sentences to describe chemicals and organs of the endocrine system.
Recall that the ability to maintain a stable internal environment in spite of changes in the external or internal environment is known as homeostasis. This complex and important task requires communication and coordination between the nervous system and the endocrine system. The endocrine glands of the system secrete chemical substances that are collectively known as hormones. These chemicals diffuse into the bloodstream and communicate with distant cells called target cells. Some substances, called paracrine secretions, travel in the interstitial fluid and affect neighboring cells. Other chemical secretions, called autocrine secretions, affect only the secreting cell. In each of these examples, the chemical substance is secreted from a cell and delivered to another cell by way of bodily fluids.
Which of the following are the functions of the endocrine system?
Regulates water and electrolyte balance Regulates metabolism Controls reproduction and development Regulates growth
Match the gland with the location in the body where it is found.
Sits on top of a kidney - Adrenal gland Found in the pelvis - Ovaries Attached to the small intestines - Pancreas Found in the neck - Thyroid gland Found in the brain - Pituitary gland
In comparison to the nervous system, the endocrine system responds __________ and its actions are __________.
slowly; long-lasting
Match each pituitary hormone with its function.
ADH: Causes kidneys to retain water; raises blood pressure LH: Promotes the secretion of sex hormones from the gonads FSH: Stimulates egg or sperm production ACTH: Stimulates the release of hormones from the adrenal cortex TSH: Stimulates the secretion of thyroid hormones PRL: Stimulates the production of milk GH: Stimulates the rate of mitosis; promotes bone growth OT: Stimulates contraction of uterine wall muscles; stimulates smooth muscle in milk-secreting glands
Match each pituitary hormone with its correct action.
Growth hormone Increases size and division rate of body cells Prolactin Sustains milk production after birth Thyroid-stimulating hormone Controls thyroid gland secretions Adrenocorticotropic hormone Controls adrenal cortex secretions Follicle-stimulating hormone Stimulates development of eggs & sperm Luteinizing hormone Controls secretions from ovaries & testes Antidiuretic hormone Causes kidneys to conserve water Oxytocin Affects muscle contraction of uterus & mammary glands
For each description, indicate the correct pancreatic hormone.
Insulin: Promotes the formation of glycogen from glucose Glucagon: Stimulates liver to breakdown glycogen Glucagon: Stimulates the breakdown of fats Insulin: Decreases blood glucose levels Glucagon: Raises blood glucose levels Insulin: Secreted by beta cells Glucagon: Secreted by alpha cells Insulin: Enhances synthesis of proteins
Complete the following sentences describing hormonal control of blood pressure.
Specific cells in the kidneys are able to respond to changes in blood pressure. If the blood pressure drops, these cells release the enzyme renin. The enzyme converts a blood protein called angiotensinogen to the peptide angiotensin I. An enzyme in the lungs converts the previous peptide into angiotensin II. One function of this last peptide is to stimulate the adrenal cortex to release the hormone aldosterone. This hormone acts to conserve sodium ions and, indirectly, water. This process will increase blood volume and blood pressure.
An increase in the body's metabolic rate is the primary effect of what hormone?
Thyroid hormone
Match each action with its hormone.
Thyroxine/thyroid gland Affects metabolic processes to increase energy & growth Calcitonin/thyroid gland Decreases calcium & phosphate levels in blood Parathyroid hormone/parathyroid gland Increases calcium & phosphate levels in blood Epinephrine & norepinephrine/adrenal medulla Actions are similar to the sympathetic response Aldosterone/adrenal cortex Regulates electrolytes in the blood Cortisol/adrenal cortex Affects glucose metabolism Adrenal androgens/adrenal cortex Supplements the major sex hormones Insulin/pancreas Decrease blood glucose levels, increases anabolic processes Glucagon/pancreas Increases blood glucose levels, increases catabolic processes
Complete the following sentences describing the differences between the various types of secretions released by cells and glands of the endocrine system.
Endocrine glands secrete hormones into the bloodstream to affect change in target cells a distance away. Exocrine glands secrete substances (like sweat) into ducts which open onto free surfaces. Paracrine secretions are released from one cell and affect change in a neighboring cell. Autocrine secretions are released from one cell and affect change in the secreting cell.
