Chapter 13 | Anatomy II
What is the function of the endocrine system?
Answer: The endocrine system regulates functions of the body to maintain homeostasis and coordinates communication.
How does the endocrine system communicate?
Answer: The endocrine system communicates by secreting hormones into the bloodstream.
What is the function of the nervous system?
Answer: The nervous system also functions in communication.
How does the nervous system communicate?
Answer: The nervous system communicates by releasing neurotransmitters into synapses.
What is a similarity between the nervous and endocrine systems?
Answer: Both systems communicate via chemicals that bind to receptor molecules.
How do hormones travel through the body?: Hormones are released into extracellular fluid and then diffuse into the blood.
What determines the method of transport for hormones in the blood?: The method of transport through the blood depends on whether the hormone is lipid-soluble or water-soluble.
What are steroid hormones made from?: Steroid hormones are produced from cholesterol.
Give examples of steroid hormones: Examples of steroid hormones include sex hormones (testosterone, estrogens) and adrenal cortex hormones (cortisol, aldosterone).
What are non-steroid hormones derived from?: Non-steroid hormones can be derived from amines (epinephrine, norepinephrine, thyroxine), proteins (growth hormone), peptides (ADH, oxytocin), or glycoproteins (TSH).
How do hormones exert their effects on metabolic processes?
Answer: Hormones alter metabolic processes by potentially changing enzyme activity and the rate of membrane transport of substances.
How do hormones deliver messages to target cells?
Answer: Hormones deliver messages by binding to their receptors on or in target cells.
Can hormones affect changes in target cells even in low concentrations?
Answer: Yes, hormones can affect changes in target cells even in extremely low concentrations.
What determines the strength of the response to hormones?
Answer: The number of receptors on the target cell determines the strength of the response.
What is upregulation?
Answer: Upregulation is an increase in the number of receptors on a target cell in response to a decrease in hormone level.
What is downregulation?
Answer: Downregulation is a decrease in the number of receptors on a target cell due to an increase in hormone level.
How do steroid hormones enter target cells?
Answer: Steroid hormones can diffuse through the lipid bilayer of cell membranes.
How do thyroid hormones enter target cells?
Answer: Thyroid hormones are thought to enter cells through specific transport methods.
Where do steroid and thyroid hormones bind to receptors?
Answer: Steroid and thyroid hormones bind to receptors inside the cell, usually in the nucleus.
What is the main difference between nonsteroid hormones and steroid hormones?
Nonsteroid hormones cannot penetrate the lipid bilayer of cell membranes, while steroid hormones can.
How do nonsteroid hormones bind to target cells?
Nonsteroid hormones bind to receptors on the target cell membrane.
What is the term for a chemical that induces changes leading to a hormone's effect?
A chemical that induces changes leading to a hormone's effect is considered a second messenger.
What is a common second messenger used by many hormones?
Many hormones use cyclic adenosine monophosphate (cAMP) as a second messenger.
What is the term for the entire process of chemical communication from outside cells to inside?
The entire process of chemical communication from outside cells to inside is called signal transduction.
What are some harmful effects of using steroids?
Some harmful effects of using steroids include decreasing natural testosterone production, stunting growth, breast development in males, male sexual characteristics in females, damage to kidneys, liver, or heart, increase in LDL cholesterol, and psychiatric problems.
What is the purpose of using growth hormone?
Growth hormone is used to enlarge muscles.
What is the purpose of using erythropoietin?
Erythropoietin is used to increase the number of red blood cells and oxygen delivery to muscles.
What are some characteristics of prostaglandins?
Prostaglandins are paracrine substances, very potent in small amounts, not stored in cells but synthesized just before release, rapidly inactivated after use, and regulate cellular responses to hormones.
What are some effects of prostaglandins?
Prostaglandins have a wide variety of effects, such as contracting or relaxing smooth muscle, stimulating or inhibiting secretion, regulating blood pressure, controlling movement of H2O, and promoting inflammation.
How is hormone secretion primarily controlled?
Answer: Hormone secretion is primarily controlled by negative feedback mechanisms.
How long can hormone effects last?
Answer: Hormone effects can be short-lived (a few minutes) or may last for days.
How are hormone secretions regulated?
Answer: Hormone secretions are precisely regulated.
What happens to hormones after they exert their effects?
Answer: Hormones are excreted in the urine after exerting their effects.
How are hormones stopped from exerting their effects?
Answer: Hormones can be broken down by enzymes, mainly from the liver, to stop their effects.
In what cases does hormone control involve positive feedback?
Answer: A small number of cases of hormone control involve positive feedback, mainly in the reproductive system.
What are the main methods of controlling hormone secretion?
Answer: The main methods of control of hormone secretion involve negative feedback.
What is negative feedback?
Answer: A control mechanism in which rising levels of a hormone lead to a decrease in hormone secretion.
How does negative feedback control hormone secretion?
Answer: Negative feedback controls hormone secretion through tropic hormones, nervous system control, and changes in the composition of the internal environment.
What are tropic hormones?
Answer: Tropic hormones are hormones that act on other glands to regulate their hormone secretion.
How does the nervous system control hormone secretion?
Answer: The nervous system directly stimulates some glands to secrete their hormones through nerve impulses.
How do changes in the composition of the internal environment affect hormone secretion?
Answer: Changing levels of specific substances in the blood stimulate or inhibit the secretion of certain hormones.
Where is the pituitary gland located?
Answer: The pituitary gland lies at the base of the brain, in the sella turcica of the sphenoid bone.
How is the pituitary gland attached to the hypothalamus?
Answer: The pituitary gland is attached to the hypothalamus by the pituitary stalk (infundibulum).
What are the two distinct portions of the pituitary gland?
Answer: The pituitary gland consists of the anterior lobe (adenohypophysis) and the posterior lobe (neurohypophysis).
How is the anterior lobe of the pituitary gland regulated?
Answer: Hypothalamic releasing hormones are transported through the Hypophyseal Portal System and stimulate cells of the anterior lobe to release hormones.
How is the posterior lobe of the pituitary gland regulated?
Answer: Nerve impulses from the hypothalamus travel through the infundibulum and stimulate nerve endings in the posterior lobe to release hormones.
What is the role of the hypothalamus in controlling hormone secretion from peripheral endocrine glands?
Answer: The hypothalamus controls hormone secretion from peripheral endocrine glands via 3-step pathways.
How does the hypothalamus communicate with the anterior pituitary gland?
Answer: Each hypothalamic-releasing hormone acts on specific hormone-secreting cells in the anterior pituitary gland.
What is the effect of the anterior pituitary hormone on peripheral endocrine glands?
Answer: The anterior pituitary hormone acts on cells in a peripheral endocrine gland to stimulate its secretion.
Are there any feedback controls involved in these pathways?
Answer: Yes, usually there are multiple negative feedback controls involved in these pathways.
What is the anterior lobe of the pituitary gland made of?
Answer: Glandular epithelial tissue
How many types of secretory cells produce anterior pituitary hormones?
Answer: 5 types
What stimulates the release of each anterior lobe hormone?
Answer: Releasing hormones from the hypothalamus
What inhibits some anterior pituitary hormones?
Answer: Inhibiting hormones from the hypothalamus
Name the anterior pituitary hormones.
Answer: Growth hormone (GH), Prolactin (PRL), Thyroid-stimulating hormone (TSH), Adrenocorticotropic hormone (ACTH), Follicle-stimulating hormone (FSH), Luteinizing hormone (LH)
What is the function of Growth Hormone?
Answer: Stimulates cells to enlarge and divide rapidly, increases amino acid uptake and protein synthesis, decreases rate of carbohydrate usage, increases rate of fat usage
What is the function of Prolactin?
Answer: Promotes milk production in females, uncertain function in males
What is the function of Thyroid-stimulating Hormone?
Answer: Stimulates secretion of thyroid hormones (T3 and T4) from thyroid gland
What is the function of Adrenocorticotropic Hormone?
Answer: Stimulates secretion of cortisol and other glucocorticoids from adrenal cortex
What is the function of Follicle-stimulating Hormone?
Answer: Causes growth & development of ovarian follicles in females, sperm production in males
What is the function of Luteinizing Hormone?
Answer: Causes ovulation in females, sex hormone production in both genders
How do hormones exert their effects on metabolic processes?
Answer: Hormones alter metabolic processes by potentially altering enzyme activity and the rate of membrane transport of substances.
How do hormones deliver messages to target cells?
Answer: Hormones deliver messages by binding to their receptors on or in target cells.
Can hormones affect changes in target cells even in low concentrations?
Answer: Yes, hormones can affect changes in target cells even in extremely low concentrations.
What determines the strength of the response to hormones?
Answer: The number of receptors on the target cell determines the strength of the response.
What is upregulation?
Answer: Upregulation is an increase in the number of receptors on a target cell in response to a decrease in hormone level.
What is downregulation?
Answer: Downregulation is a decrease in the number of receptors on a target cell due to an increase in hormone level.
How do steroid hormones enter target cells?
Answer: Steroid hormones can diffuse through the lipid bilayer of cell membranes.
How do thyroid hormones enter target cells?
Answer: Thyroid hormones are thought to enter cells by specific transport methods.
What are the characteristics of hypopituitary dwarfism?
Answer: Hypopituitary dwarfism is caused by a deficiency of growth hormone during childhood, resulting in short stature but normal body proportions and mental development.
What causes gigantism?
Answer: Gigantism is caused by the oversecretion of growth hormone during childhood, resulting in excessive height and potential metabolic problems, often caused by a pituitary tumor.
What is acromegaly?
Answer: Acromegaly is caused by the oversecretion of growth hormone during adulthood, resulting in no increase in height but thickening of bones and enlargement of certain body parts.
What is the composition of the posterior lobe of the pituitary gland?
Answer: The posterior lobe of the pituitary gland consists of nerve fibers from the hypothalamus and neuroglia.
How are hormones produced in the hypothalamus related to the posterior pituitary gland?
Answer: Hormones produced by neurons in the hypothalamus are stored and released by the posterior pituitary gland.
How are hormones transported to the posterior pituitary gland?
Answer: Hormones are transported to the posterior pituitary gland via the pituitary stalk (infundibulum).
What is the function of antidiuretic hormone (ADH, vasopressin)?
Answer: ADH decreases urine production by reducing the volume of water the kidneys excrete and also causes vasoconstriction to increase blood pressure.
What is the function of oxytocin?
Answer: Oxytocin causes muscle contraction in the uterine wall during childbirth and milk ejection during lactation. It may also play a role in sperm movement or sexual response in males.
How is oxytocin regulated in the body?
Answer: Oxytocin is regulated by a positive feedback mechanism to oxytocin in the blood, leading to increased intensity of uterine contractions during childbirth.
What is the role of oxytocin in milk ejection?
Answer: Oxytocin triggers milk ejection ("letdown" reflex) in women producing milk.
What are the functions of oxytocin in nonsexual relationships?
Answer: In nonsexual relationships, oxytocin promotes nurturing and affectionate behavior through social bonding. It is often referred to as the "love hormone."
Where is the thyroid gland located?
Answer: The thyroid gland lies just below the larynx, anterior and lateral to the trachea.
What is the special ability of the thyroid gland?
Answer: The thyroid gland has the special ability to remove iodine from the blood.
What are the three hormones produced by the thyroid gland?
Answer: T4 (thyroxine), T3 (triiodothyronine), and calcitonin.
Which cells in the thyroid gland produce T3 and T4 hormones?
Answer: Follicular cells.
What type of cells produce calcitonin in the thyroid gland?
Answer: Extra- or parafollicular cells.
What is the function of calcitonin in the body?
Answer: Calcitonin inhibits osteoclast activity, stimulates calcium uptake, and incorporates calcium into the bone matrix.
What are the major metabolic hormones produced by the thyroid gland?
Answer: T3 and T4.
What is the structure of the thyroid gland?
Answer: The thyroid gland is composed of round secretory units called follicles, surrounded by a single layer of follicular cells, and filled with viscous colloid.
What are the two iodine-containing compounds that make up the thyroid hormone?
Answer: T4 (thyroxine) and T3 (triiodothyronine).
What are the symptoms of hypothyroid syndrome?
Answer: Low metabolic rate, dry skin, cold, puffy eyes, edema, lethargy, constipation, mental sluggishness.
What is a goiter and what causes it?
Answer: A goiter is the enlargement of the thyroid gland, often caused by a lack of iodine.
What is the treatment for hypothyroid syndrome?
Answer: Hypothyroid syndrome can be treated with iodine supplements or hormone replacement therapy.
What are the symptoms of infantile hypothyroidism?
Answer: Stunted growth, abnormal bone formation, intellectual disability, and sluggishness.
What are the two general types of hormones?
Answer: Steroid or steroid-like hormones, and non-steroid hormones.
What are steroid hormones derived from?
Answer: Steroid hormones are produced from cholesterol.
Give an example of a steroid hormone.
Answer: Testosterone, estrogens, cortisol, aldosterone.
What are non-steroid hormones derived from?
Answer: Non-steroid hormones can be derived from amines, proteins, peptides, or glycoproteins.
Give an example of a non-steroid hormone derived from amines.
Answer: Epinephrine, norepinephrine, thyroxine.
What are the parathyroid glands responsible for?
Answer: The parathyroid glands secrete PTH (Parathyroid hormone) and regulate concentrations of calcium and phosphate in the blood.
What are the actions of PTH?
Answer: PTH increases blood levels of calcium and decreases phosphate. It stimulates bone resorption, calcium absorption, and conserves calcium while excreting phosphate in urine.
What is Graves disease?
Answer: Graves disease is a form of hyperthyroidism and is thought to be an autoimmune disease.
What are the symptoms of Graves disease?
Answer: Symptoms include a high metabolic rate, rapid and irregular heartbeat, increased sweating, nervousness, and weight loss. It may also cause exophthalmus, which is the protrusion of eyeballs due to swelling in tissues behind the eye.
How can Graves disease be treated?
Answer: Graves disease can be treated by surgical removal of the thyroid gland or by ingestion of radioactive iodine to destroy the most active thyroid cells.
What are adrenal glands also known as?
Answer: Suprarenal glands
Where are the adrenal glands located in the body?
Answer: They sit like a cap on each kidney.
What are the two areas of the adrenal gland that secrete hormones?
Answer: The adrenal cortex and the adrenal medulla.
What is the main function of adrenal hormones?
Answer: They play roles in maintaining blood sodium levels and responding to stress, and also include certain sex hormones.
What types of hormones are secreted by the adrenal cortex?
Answer: Aldosterone, Cortisol, and Sex hormones.
What types of hormones are secreted by the adrenal medulla?
Answer: 80% Epinephrine and 20% Norepinephrine.
What are the two hormones secreted by the Adrenal Medulla?
Answer: Epinephrine and Norepinephrine
What are the effects of Epinephrine on the body?
Answer: Epinephrine stimulates metabolic activities, bronchial dilation, and blood flow to skeletal muscles and the heart.
What is the main function of Norepinephrine?
Answer: Norepinephrine influences peripheral vasoconstriction and blood pressure.
What are the three zones of the Adrenal Cortex?
Answer: Zona glomerulosa, Zona fasciculata, and Zona reticularis.
What hormones are produced by the Zona glomerulosa?
Answer: Aldosterone and other mineralocorticoids.
What hormones are produced by the Zona fasciculata?
Answer: Cortisol and other glucocorticoids.
What hormones are produced by the Zona reticularis?
Answer: Male sex hormones called androgens.
What is the function of Aldosterone?
Answer: Aldosterone promotes excretion of K+ ions by the kidney and conservation of Na+ by the kidney.
What is the Renin-Angiotensin System?
Answer: The Renin-Angiotensin System helps maintain normal blood pressure and promotes secretion of aldosterone.
What are the effects of excessive levels of glucocorticoids?
Answer: Excessive levels of glucocorticoids depress cartilage and bone formation, inhibit inflammation, depress the immune system, and promote changes in cardiovascular, neural, and gastrointestinal function.
How is cortisol secretion regulated?
Answer: Cortisol secretion is regulated by a 3-step hormone pathway and exerts negative feedback on its own production pathway.
What is Addison Disease?: A condition caused by insufficient hormone secretion from the adrenal cortex, resulting in electrolyte and glucose imbalances, dehydration, low blood pressure, fatigue, nausea, and increased skin pigmentation.
What can be a fatal consequence of Addison Disease?: Severe electrolyte imbalance.
What is Cushing Syndrome?: A condition caused by hypersecretion of cortisol, either due to an adrenal tumor or excess secretion of ACTH by the anterior pituitary.
What are the two major types of secretory tissue in the pancreas?: Endocrine and exocrine.
What is the endocrine function of the pancreas?: Secretes hormones into body fluids.
What is the exocrine function of the pancreas?: Secretes digestive juices through a duct.
What are the three hormones secreted by the endocrine cells of the pancreas?: Glucagon, insulin, and somatostatin.
What does glucagon do?: Increases blood glucose.
What does insulin do?: Decreases blood glucose.
What does somatostatin do?: Inhibits secretion of insulin and glucagon.
Where is the pancreas located?: Posterior to the stomach.
What transports digestive juice from the pancreas to the duodenum?: Pancreatic duct.
What is diabetes mellitus?: A metabolic disease resulting from lack of insulin or inability of cells to recognize insulin, leading to elevated blood glucose and potential damage to eyes, heart, kidneys, and nerves.
What are the consequences of diabetes mellitus?: Disturbances in carbohydrate, protein, and fat metabolism, tissue wasting, weight loss, increased hunger, fatigue, poor wound healing, and growth stunting in children.
What happens to glucose in diabetes mellitus?: It cannot enter cells in normal quantities, resulting in hyperglycemia.
What happens when glucose spills into urine in diabetes mellitus?: It leads to glycosuria (glucose in urine) and dehydration due to water following by osmosis, causing increased thirst.
What is Type 1 Diabetes Mellitus also known as?: Type 1 Diabetes Mellitus is also known as juvenile or insulin-dependent diabetes.
What causes Type 1 Diabetes Mellitus?: Type 1 Diabetes Mellitus is caused by an autoimmune disease where the immune system destroys the beta cells of the pancreas.
What is the main characteristic of Type 1 Diabetes Mellitus?: Type 1 Diabetes Mellitus results in a lack of insulin production.
What percentage of diabetes cases are Type 1?: 5-10% of diabetes cases are Type 1.
What is Type 2 Diabetes Mellitus also known as?: Type 2 Diabetes Mellitus is also known as maturity-onset or non-insulin-dependent diabetes.
What is the main difference between Type 1 and Type 2 Diabetes Mellitus?: In Type 2 Diabetes Mellitus, insulin is produced but body cells are unable to recognize it.
What are some complications of Type 2 Diabetes Mellitus?: Complications of Type 2 Diabetes Mellitus include coronary artery disease, nerve or retinal damage.
How is insulin administered in Type 1 Diabetes Mellitus?: Insulin can be administered through injection, an insulin pump, or in aerosol form.
How is human insulin produced?: Human insulin can be synthesized using recombinant DNA technology; insulin is produced by genetically altered bacteria.
What are some treatment options for Type 2 Diabetes Mellitus?: Treatment options for Type 2 Diabetes Mellitus include a low carbohydrate, high protein diet, regular exercise, medications that increase glucose production, and gastric bypass surgery.
What is the function of the pineal gland?
Answer: The pineal gland secretes melatonin, which regulates circadian rhythms.
Where is the thymus gland located?
Answer: The thymus gland is found in the mediastinum, between the lungs.
What hormones are produced by the ovaries?
Answer: The ovaries produce estrogens and progesterone.
What hormone is produced by the testes?
Answer: The testes produce testosterone.
What is the role of the placenta in hormone production?
Answer: The placenta produces estrogens, progesterone, and a gonadotropin.
What do digestive glands produce?
Answer: Digestive glands produce hormones to regulate digestion.
What hormone does the heart produce?
Answer: The heart produces natriuretic peptides, which stimulate Na+ secretion in urine.
What hormone does the kidney produce?
Answer: The kidney produces erythropoietin, which stimulates red blood cell formation.
What is the role of the hypothalamus in controlling hormone secretion from peripheral endocrine glands?
Answer: The hypothalamus controls hormone secretion from peripheral endocrine glands via 3-step pathways.
How do hypothalamic-releasing hormones act on hormone-secreting cells in the anterior pituitary gland?
Answer: Each hypothalamic-releasing hormone acts on specific hormone-secreting cells in the anterior pituitary gland.
What is the effect of anterior pituitary hormone on peripheral endocrine glands?
Answer: Anterior pituitary hormone stimulates secretion from cells in peripheral endocrine glands.
What is the role of negative feedback controls in hypothalamic control of peripheral endocrine glands?
Answer: Multiple negative feedback controls are involved in these pathways.
What is the definition of stress?
Answer: Stress is the condition produced in response to stressors.
What are examples of psychological stressors?
Answer: Danger, personal loss, anger, fear, guilt.
What are examples of physical stressors?
Answer: Temperature extremes, infection, injury, O2 deficiency.
What is the response to stress called?
Answer: The response to stress is called General Adaptation Syndrome (GAS).
What are the two main stages of General Adaptation Syndrome (GAS)?
Answer: The two main stages of GAS are the alarm stage and the resistance stage.
What happens during the alarm stage of General Adaptation Syndrome (GAS)?
Answer: During the alarm stage, there is an immediate fight or flight response, increased blood glucose, heart rate, breathing rate, blood pressure, and epinephrine secretion.
What happens during the resistance stage of General Adaptation Syndrome (GAS)?
Answer: During the resistance stage, cortisol, glucagon, and growth hormone mobilize energy sources for other tissues and organs, while ADH and renin cause water retention.
What is the main characteristic of the Exhaustion Stage?
Answer: Wasting due to depletion of nutrients in the body
What is the effect of long-term oversecretion of cortisol?
Answer: Suppression of immune system
What can happen as a result of the Exhaustion Stage?
Answer: Death
What are some life-span changes in the endocrine system?
Answer: Decrease in size of endocrine glands
What happens to muscular and skeletal strength as GH levels decline?
Answer: Decrease
Why do ADH levels increase in the body during life-span changes?
Answer: Slower elimination by liver and kidneys
What happens to calcitonin levels during life-span changes?
Answer: Decrease, increasing risk of osteoporosis
How do PTH level changes contribute to the risk of osteoporosis?
Answer: Increases the risk, especially in females
What may develop in the body during life-span changes?
Answer: Insulin resistance
How do changes in melatonin secretion affect the body clock?
Answer: They affect the body's sleep-wake cycle
What happens to thymosin production during life-span changes?
Answer: It declines, increasing the risk of infections.