Chapter 18: Blood
List the hormones secreted by the pineal gland and describe their possible functions.
Melatonin: can inhibit reproductive maturation May regulate sleep-wake cycle
Locate the adrenal glands and describe the two major layers.
Paired, pyramid-shaped organ that sits on top of the kidneys Structurally and functionally, the adrenal glands are four glands in one o Adrenal medulla (inner area) -Epinephrine -Norepinephrine o Adrenal Cortex (outer area) -Composed of 3 layers Zona glomerulosa Zona fasciculata Zona reticularis
Portal system
Portal System: connects hypothalamus and anterior pituitary Hormones are produced in hypothalamus neurons Through portal system the hormones inhibit or stimulate hormone production in anterior pituitary
Thyroid-stimulating hormone (TSH): state their target tissues, actions, and conditions that lead to their release.
Target tissues: Thyroid gland Actions: TSH release causes the secretion of hormones T3 and T4 from and within the thyroid gland; increasing the activity of phospholipase that opens Ca2+ channels increasing Ca2+ concentration in cells of the thyroid gland Negative feedback- T3 and T4 inhibit TRH and TSH secretion Conditions that lead to their release: increased thyroid hormone secretion
Prolactin: state their target tissues, actions, and conditions that lead to their release.
Target tissues: ovaries and mammary glands in females Actions: milk production in lactating women, increased response of follicle to LH and FSH; unclear functions in males Conditions that lead to their release: role in milk production
Describe the functions of the hormones secreted by the thymus, digestive system, heart, and kidneys.
Thymus Hormones: Thymopoientins and Thymosin -essential for development of T lymphocytes (T cells) of the immune system Digestive System Hormones: gastrin secretin and cholecystokinin -regulate digestive functions Kidneys Hormones: erythropoietin - stimulate red blood cells production
List the major category of hormone produced by Zona Fasciculata of the adrenal cortex and state their general actions.
Zona Fasciculata Glucocorticoids - help body resist stress Cortisol - Gluconeogenesis, rise in blood glucose, fatty acids, and amino acids
Describe the role of calcitonin in maintenance of blood calcium levels and in bone health.
(Secreted by the thyroid gland) Parafollicular cells secreted by calcitonin Directly regulated by blood ca2+ levels -Blood Ca2+ levels drop = calcitonin levels drop -Blood Ca2+ levels rise = calcitonin levels rise Calcitonin targets skeleton to: inhibit osteoclast activity- reduce release calcium from bone matrix stimulate Ca2+ uptake - incorporation into bone matrix
Explain the conditions that lead to secretion of T3 and T4 and describe the effects of T3 and T4 on their target tissues.
(thyroid hormones) Triiodothyronine (T3) -has two tyrosine's with three bound iodine atoms (90%), more potent Tetraiodothyronine (T4) -has 2 tyrosine molecules and 4 bound iodine atoms (10%), 33-40% of T4 converted to T3 in cells Conditions that lead to secretion of T3 and T4: Thyroid-stimulating hormone (TSH) from the anterior pituitary stimulates thyroid synthesis and secretion Regulated by TRH and TSH TSH from anterior pituitary increases T3 and T4 secretion T3 and T4 inhibit TSH and TRH secretion (negative feedback) Target tissue: most cells of the body Effects: increased rate of glucose, fat, protein, and metabolism in many tissues Increased body temperature Maintenance of blood pressure Regulation of tissue growth Development of skeletal and nervous systems Maturation and reproductive capillaries
List the major hormones of the posterior pituitary gland
Antidiuretic hormone (ADH) Oxytocin
List the major hormones produced by the anterior pituitary gland
Growth Hormone (GH) Thyroid-stimulating hormone (TSH) Adrenocorticotropic hormone (ACTH) Melanocyte-stimulating hormone (MSH) Luteinizing hormone (LH) Follicle-stimulating hormone (FSH) Prolactin
Identify the structure that serves as the primary point of interaction between the nervous and endocrine systems.
Hypothalamus
List the two major hormones produced by the pancreas and state their target tissues, actions, and conditions that lead to their release.
Insulin Nervous system relies on blood glucose levels maintained by insulin Target tissue: liver, adipose tissue, muscle, satiety center in hypothalamus Actions: increase the uptake of glucose and amino acids in cells Glucose: used for energy, stored for glycogen, converted into fats Amino Acids: used to synthesize proteins Condition that leads to release: blood glucose is elevated Glucagon Target tissue: liver Actions: causes breakdown glycogen to glucose stimulates synthesis of glucose from amino acids liver releases glucose into the blood Condition that leads to release: blood glucose levels decline
Location and structure of the pituitary gland
Location: Connected to the base of the brain, just inferior to the hypothalamus Structure: Divided into 2 lobes (Posterior Pituitary and Anterior Pituitary)
List the major hormones produced by the adrenal medulla and state their target tissues, actions, and conditions that lead to their release.
Major hormones produced: 80% epinephrine (adrenaline), 20% norepinephrine Target tissues: heart, blood, vessels, liver, adipose cells Actions: prepares for physical activity and major component in fight or flight Conditions that lead to their release: released by sympathetic division of ANS in response to; emotions, injury, stress, exercise, low blood glucose levels
Explain the physical, neural, and vascular connections between the hypothalamus and the pituitary gland.
Physical: -Pituitary recreates at least 9 hormones that regulate numerous body functions as well as other endocrine glands -Hypothalamus regulates pituitary gland activity through neurohormones and action potentials Neural: -Posterior pituitary develops from floor of brain and consist of the infundibulum and neurohypophysis -Anterior pituitary develops from the roof of mouth Vascular: 1. Hypothalamohypophysial portal system connects the hypothalamus and the anterior pituitary -Neurohormoes are produced in hypothalamic neurons -Through the portal system, the neurohormones inhibit or stimulate hormones production in the anterior pituitary 2. Hypothalamohypophysial tract connects hypothalamus and posterior pituitary -neurohormones are produced in hypothalamic neurons -neurohormones move down the axons of the tract and are secreted from the posterior pituitary
Explain how the placenta acts as a temporary endocrine gland.
Secretes human chorionic gonadotropin (hCG), essential for maintained pregnancy
Explain the conditions that lead to secretion of parathyroid hormone and describe the effects of parathyroid hormone on its target tissues.
Target tissue: Bones, kidneys, small intestine -promotes Ca2+ reabsorption by the kidneys and the formation of active vitamin D by the kidneys -active vitamin D increases Ca2+ absorption by the intestine (decreased blood Ca2+ levels stimulate PTH secretion)
Antidiuretic hormone: state their target tissues, actions, and conditions that lead to their release.
Target tissue: Kidneys Actions: promotes increased water absorption by the kidneys Conditions that lead to their release: increased water reabsorption (less water is lost in the form of urine)
Oxytocin: state their target tissues, actions, and conditions that lead to their release.
Target tissue: Uterus; mammary glands Actions: promotes uterine contractions during delivery Causes milk ejection in lactating women Conditions that lead to their release: increased uterine contractions during birth; increased milk expulsion from mammary glands; unclear function in males
Adrenocorticotropic hormone (ACTH): state their target tissues, actions, and conditions that lead to their release.
Target tissues: Adrenal cortex Actions: Causes cortisol secretion from the adrenal cortex (glucocorticoid from the zona fasciculata) Causes cortisol secretion from the adrenal cortex (mineralocorticoid from the zona glomerulosa) Conditions that lead to their release: increased glucocorticoid hormone secretion
Follicle-stimulating hormone (FSH): state their target tissues, actions, and conditions that lead to their release.
Target tissues: Follicles in ovaries in females, seminiferous tubules in males Actions: both hormones regulate production of gametes and reproductive hormones (testosterone in males and estrogen/progesterone in females) Conditions that lead to their release: follicle maturation and estrogen secretion in ovaries, sperm cell production in testes
Melanocyte-stimulating hormone (MSH): state their target tissues, actions, and conditions that lead to their release.
Target tissues: Melanocytes in the skin Actions: causes melanocytes to increase production of melanin in the skin Conditions that lead to their release: increased melanin production in melanocytes to make the skin darker in color
Luteinizing hormone (LH): state their target tissues, actions, and conditions that lead to their release.
Target tissues: Ovaries in females; Testes in males Actions: both hormones regulate production of gametes and reproductive hormones (testosterone in males and estrogen/progesterone in females) Conditions that lead to their release: Ovulation and progesterone production in ovaries, testosterone synthesis and support for sperm cells in testes
Growth hormones (GH): state their target tissues, actions, and conditions that lead to their release.
Target tissues: most tissues Actions: regulator of metabolism Conditions that lead to their release: Secretion increases in response to low blood glucose, stress, and an increase in certain amino acids (plays an important role in regulating nutrient levels between meals) - Regulated by two hypothalamic hormones (growth hormone-releasing hormone GHRH, growth hormone-releasing GHIH)
List and describe the functions of the hormones secreted by the testes and ovaries.
Testes o Testosterone: maturation of male reproductive organs, causes appearances of secondary sex characteristics and sex drive, necessary for sperm production, maintains sex organs in their functional state Ovaries o Progesterone: maturation of reproductive organs, appearance of secondary sexual characteristics, breast development cyclical changes in uterine mucosa
Describe the location and structure of the parathyroid glands.
Tiny glands (4) embedded in the posterior aspect of the thyroid The parathyroid glands are two pairs of small, oval-shaped glands. They are located next to the two thyroid gland lobes in the neck. Each gland is usually about the size of a pea.
Tract
Tract: connects hypothalamus and posterior pituitary Neurohormones produced in hypothalamic neurons Hormones move down axons of tract and are secreted from posterior pituitary
List the major category of hormone produced by Zona Glomerulosa of the adrenal cortex and state their general actions.
Zona Glomerulosa o Mineralocorticoids - regulate electrolytes in extracellular fluid Aldosterone - most important mineralocorticoid Maintains Na+ balance by reducing the excretion of Na+ from the body Stimulates reabsorption of Na+ by the kidneys Decrease K+ and H+ levels in the blood
List the major category of hormone produced by Zona Reticularis of the adrenal cortex and state their general actions.
Zona Reticularis o Gonadocorticoids (Sex Hormones) - onset of puberty, appearance secondary sex characteristics, sex drive in females Androgens - onset of puberty
Describe the structure of the thyroid gland.
o 1 of largest endocrine glands o located anterior neck o consists of 2 lateral lobes connected by median tissue mass (isthmus) Follicles - produce thyroglobulin Parafollicular cells - produce hormone calcitonin
Describe the effects of hypo-secretion of thyroid hormones.
o Decreased metabolic rate, low body temp, cold intolerance o Weight gain, reduced appetite o Reduced heart rate, reduced blood pressure, dilated and enlarged heart o Weak, untoned skeletal muscles; sluggish movements o constipation o myxedema (swelling of face and body) as result of subcutaneous mucoprotein deposits o Apathy, somnolence o Coarse hair; rough, dry skin o Decreased iodide uptake o Possible goiter (enlargement of thyroid gland) due to loss of negative feedback
Describe the effects of hyper-secretion of thyroid hormones.
o Increased metabolic rate, high body temperature, heat intolerance o Weight loss, increased appetite o Copious sweating; warm, flushed skin o Weak skeletal muscles that exhibit tremors, quick movements with exaggerated reflexes o Bouts of diarrhea o Exophthalmos (protruding eyes) as result of connective tissue proliferation and other deposits behind the eye o Hyperactivity, insomnia, restlessness, irritability, short attention span o Soft, smooth hair and skin o Increased iodide uptake Almost always a goiter
Describe the role of parathyroid hormone in maintenance of blood calcium levels.
o Secrete a polypeptide hormone called parathyroid hormone (PTH) PTH is essential in regulating Ca2+ balance in blood (more important than calcitonin) PTH increases the release of Ca2+ from bones into blood by increasing the number of active osteoclasts PTH: -promotes Ca2+ reabsorption by the kidneys and the formation of active vitamin D by the kidneys -active vitamin D increases Ca2+ absorption by the intestine (decreased blood Ca2+ levels stimulate PTH secretion)
Describe the location and structure of the pancreas and its role as a dual-function gland
o Triangular gland o Has both exocrine and endocrine cells o Located behind the stomach Acinar cells: produce enzyme rich juice used for digestion (exocrine product) Pancreatic islets: produce hormones (endocrine product) Alpha (glucagon), Beta (insulin)
