Exam 4: Endocrine System
Kidneys
secrete hormones that regulate blood cell production and the rate of calcium and phosphate absorbed by the intestinal tract.
Name the organs in the endocrine system.
Hypothalamus, Pituitary gland, Thyroid gland, Adrenal glands, Pancreas/ Pancreatic islets, Pineal gland, Parathyroid glands
Organs of the endocrine system
Hypothalamus, pituitary gland, thyroid gland, adrenal glands, pancreatic islets, pineal gland, parathyroid glands.
what thyroid hormone aids in calcium regulation?
calcitonin
Hypothalamo-hyphphyseal portal system
chemical signaling between the hypothalamus and anterior pituitary is accomplished by a capillary network
regulatory hormone
control the secretory activities of endocrine cells in the anterior lobe of the pituitary gland.
What effects would increased circulating levels of glucocorticoids have on the pituitary secretion of ACTH?
it would inhibit the release of CRH by the hypothalamus. The lack of CRH decreases the secretion of ACTH from the pituitary gland, so ACTH levels would decrease.
The release of which pituitary hormone would lead to an increased level of somatomedins in the blood?
mediate the action of growth hormone (GH) increases levels of GH typically accompany increased levels of somatomedins.
median eminence
secreting specific regulatory glands, the hypothalamus controls the production/ release of hormones from the anterior lobe of the pituitary gland. Neurons in the hypothalamus release hormones at capillary beds in a region of the hypothalamus called the...
Gonads
secrets hormones affecting growth, metabolism, and sexual characteristics, and other hormones that coordinate the activities of organs in the reproductive system.
Heart
secrets hormones involved in regulating blood volume.
Thymus
secrets hormones involved in stimulating and coordinating the immune response.
Hypothalamus
secrets hormones involved with fluid balance, smooth muscle concentration, and the control of hormone secretion by the anterior lobe of the pituitary gland.
Thyroid gland
secrets hormones that effect metabolic rate and calcium ion levels in body fluids.
Pineal glans
secrets melatonin, which affects reproductive function and helps establish circadian (day/night) rhythms.
Pituitary gland
secrets multiple hormones that regulate the endocrine activities of the adrenal cortex, thyroid gland and reproductive organs, and a hormone that stimulates melanin production.
Digestive tract
secrets nurerous hormones involved in coordinating system functions, glucose metabolism, and appetite.
Why do signs of symptoms of decreased thyroxine concentrations not appear until after about a week after a tyroidectomy?
takes many days after the removal of the thyroid glad for blood levels of thyroxine to decrease.
In a dehydrated person, how would the amount of ADH released by the posterior lobe of the pituitary change?
the amount of ADH released by the posterior lobe of the pituitary gland increases in response to increased amounts of blood osmotic pressure resulting from an increase in solute concentration.
Regulatory hormones are released into the hypophyseal portal system for delivery to where?
the anterior lobe of the pituitary gland.
name the 2 lobes of the pituitary gland
the anterior lobe/ adenohypophysis the posterior lobe/ neurohypophysis
What are the chemical means of cellular communication in the nervous and endocrine systems?
the nervous system communicates with neurotransmitters, whereas the endocrine system communicates with hormones.
Name the hormones of the thyroid gland?
thyroxine (T4) triiodothyronine (T3), calcitonin
In the hypothalamus and pituitary gland the outflow of blood goes where?
to systemic circulation.
Effects of Parathyroid hormone on peripheral tissues.
-"CAlCIUM HOMEOSTASIS"
List the hypothalamic releasing hormones
TRH CRH GnRH GH-RH PRF
Pancreatic islets
secrete hormones regulating the rate of glucose uptake and utilization by body tissues.
isthmus
left and right lobes of the tyroid gland are connected by this
Gonadotropins (FSH and LH)
- Follicle -Stimulating hormones --Ovary -Luteinizing hormone --Testis Both stimulate production of hormones regulating reproduction in males and females.
Negative feedback mechanisms
- The hypothalamus releases a releasing hormone (RH) that triggers the release of a hormone from the anterior lobe of the pituitary gland (hormone 1) -The pituitary hormone (Hormone 1) stimuates the release of a hormone from the target organ (hormone 2) - The hormone from the target organ (hormone 2) suppresses the release of both the hypothalamic releasing hormone (RH) and the pituitary hormone (hormone 1)
Pineal gland
-"REGULATING PROCESSES THAT FOLLOW A CIRCADIAN OR DAY/NIGHT CYCLE PATTERN" -Functions of melatonin in humans -- inhibiting reproductive functions --protecting against damage by free radicals -Setting circadian rhythms.
Pancreas
-"REGULATION OF BLOOD GLUCOSE LEVELS" -exocrine portion of this produces enzymes that assist in the digestion of food.
effects of thyroid hormones on peripheral tissues
-"STIMULATION OF TISSUE METABOLISM" -increased rate in O2 and energy consumption, in kids it may cause a rise in body temp. -increased heart rate and force of contraction; generally results in a rise in BP -increases sensitivity to sympathetic stimulation - maintenance of normal sensitivity of respiratory centers to changes in O2 and CO2 concentrations -Stimulation of activity in other endocrine tissues -accelerated turnover of minerals in bone.
Adrenal Glands
-"Water and electrolyte balance; glucose metabolism; sex hormones"
Hormones of the posterior lobe of the pituitary gland:
-ADH: antidiuretic hormone -OXT: oxytocin
ACTH
-Adreno- corticotropic hormone - Adrenal gland -Stimulates production of steriod hormone
Identify the types of cells in the pancreatic islets and the hormones produced by each
-Alpha cells: they produce glucagon, it raises blood glucose levels by increasing the rates of glucose released by the liver. -Beta cells: produce insulin, which lowers blood glucose levels by increasing the rate of glucose uptake and utilization by cells, and by increasing glycogen synthesis in skeletal muscles and in the liver. -Exocrine cells, make small clusters that secrete into the lumen continuous with the pancreatic duct. The clusters are called pancreatic acini. -Delta cells: produce a peptide hormone identical to growth hormone-inhibiting hormone (GH-IH), it suppresses the release of glucagon and insulin by other islet cells and slows the rates of food absorption and enzyme secretion along the intestinal tract. -F cells: produce pancreatic polypeptide (PP). It inhibits gallbladder contractions and regulates the production of some pancreatic enzymes. It can also help control the rate of nutrient absorption by the intestinal tract.
ADH
-Antidiuretic hormone -Kidney -Water balance
Similarities between communication in the endocrine system and in the nervous system:
-Both system rely on the release of chemicals that bind to specific receptors on their target cells. -The 2 systems share many chemical messengers. -Both systems are regulated by negative feedback control mechanisms. -Both systems function to preserve homeostasis by coordinating and regulating the activities of other cells, tissues, organs and systems.
Hypothalamus -Indirect control through release of regulatory hormones -- These regulatory hormones can be stimulatory (releasing) or inhibitory:
-Corticotropin- releasing hormone (CRH) -Thyrotropin-releasing hormone (TRH) -Growth Hormone- releasing hormone (GH-RH) -Growth hormone- inhibiting hormone (GH- IH) -Procactin- releasing hormone factor (PRF) - Prolactin- inhibiting hormone (PIH) -Gonadotropin- releasing hormone (GnRH)
GH
-Growth hormone -Musculoskeletal system -Stimulates cell and tissue growth
Adrenal glands: Zona reticularis
-Hormones: androgens -targets: skins, bones and other tissues, but minimal effects in normal adults -hormonal effects: adrenal androgens stimulate the development of pubic hair in body and girls before puberty.
Adrenal glands: Zona fasciclata
-Hormones: glucocorticoids, primarily cortison -targets: most cells -hormonal effects: increase glucose and glycogen formation and reduces inflammation -stimulated by ACTH
MSH
-Melanocyte- stimulating hormone - Stimulates production of melanin in skin
OXT
-Oxytocin -Uterus -Smooth muscle contraction
PRL
-Prolactin -mammary gland -stimulates mammary gland development
Direct release of hormones
-Sensory stimulation -Osmoreceptor simulation
Hormones of the anterior lobe of the pituitary gland:
-TSH:thyroid stimulating hormone -ACTH: adrenocorticotropic hormone - Gonadotropins (FSH/LH): Follicle stimulating hormone (female) Luteinizing hormone (male) -GH: growth hormone -PRL: prolactin -MSH: Melanocyte stimulating hormone
The pituitary gland has what parts?
-The anterior lobe of the pituitary gland/ Adenohypophysis -The posterior lobe of the pituitary gland/ Neurohypophysis.
TSH
-Thyroid- stimulating hormone -Thyroid gland -Stimulates production of thyroid hormones
identify and describe 2 types of diabetes mellitus.
-Type 1 diabetes: inadequate insulin production by pancreatic beta cells. 5-10% of diabetes and it often develops in children and young adults. -Type 2 diabetes: most common form. bodies don't respond appropriately to insulin.
Hypophyseal portal system:
-capillary networks supplied by the superior hypophyseal artery. -Portal vessels -Second capillary network.
Identify some clinical problems associated with diabetes mellitus.
-diabetic retinopathy - diabetic nephropathy -diabetic neuropathy
differentiate between a first messenger and a second messenger
-first messenger: hormone whose binding to a protein receptor in the plasma membrane gives rise to a second messenger in the cytoplasm. -second messenger: changes the rate of various metabolic reactions by acting as a enzyme activator, an enzyme inhibitor or a confactor.
Adrenal glands: Zona glomerulosa
-hormones: mineralocotidcoids, primarily aldosterone -targets:kidneys - hormonal effects: increased renal absorption of Na+, and water; accelerates urinary loss of K- -Stimulated by renin- angiotensin system; inhibited by opposing hormones.
List 3 functions of melatonin
-inhibits reproductive functions -protecting against damage by free radicals -setting circadian rhythms
Hypothalamus + location.
-part of the diencephalon of the brain. -just superior to the pituitary gland, which is found in the sella turcica, a depression found within the sphenoid bone at the base of the skull. -has neurons within it that secrete regulatory hormones that have a direct influence on hormone- secreting cells in the pituitary gland.
Insulin and glucagon
-produced by the endocrine pancreas. - both hormones that are responsible for the regulation of blood glucose levels.
Describe the structural classification of hormones.
1. Amino acid derivatives (thyroid hormones, catecholamines, and tryptophan derivatives) 2. Peptide hormones- chains of amino acids that are synthesized as pro-hormones 3. Lipid derivatives- which contain carbon rings and side chains that are built from fatty acids or cholesterol.
identify 3 mechanisms by which the hypothalamus integrates neural and endocrine function.
1. Secretion of antiduretic hormone (ADH) and oxytocin (OXT) 2. secretion of regulatory hormones that control activity of the anterior lobe of the pituitary gland. 3. neural (sympathetic) control over the endocrine cells of the adrenal medullae
Hypothalamus and pituitary gland
1. hypothalamus neurons that synthesize antiduretic hormone (ADH) and oxytocin (OXT) 2. Hypothalamus cells secreting regulatory hormones. 3. Autonomic centers within the hypothalamus.
List the 3 zones of the adrenal cortex
Adrenal Capsule, Adrenal Cortex, Adrenal Medulla
The secretion of which hormone lowers blood glucose concentrations?
Beta cells!
Name and describe the characteristics and functions of the blood vessels that link the hypothalamus with the anterior lobe of the pituitary gland.
Blood vessels of the hypophyseal portal system link the hypothalamus and anterior lobe of the pituitary gland. Unusually permeable fenestrated capillary beds in each structure are connected by portal vessels. This arrangement ensures that hypothalamic regulatory hormones reach the "downstream" endocrine cells of the anterior lobe directly, before mixing with, and being diluted by, the general circulation.
Organs with secondary endocrine functions:
Heart, Thymus, digestive tract, kidneys, gonads.
What effect would increased cortisol levels have on blood glucose levels?
Increased cortisol levels would result in increases blood glucose levels, b/c cortisol decreases the use of glucose by cells while increasing both the available glucose (by promoting the breakdown of glycogen) and the conversion rate of amino acids to carbs.
Increased amounts of light would inhibit the production of which hormone?
Melatonin
Endocrine system
Organs whose primary function is the production of hormones or paracrine factors.
how does paracrine communication differ from endocrine communication?
Paracrine communication: release of paracrine factors into the extracellular fluid and is limited to the local area. Endocrine communication: release of hormones into the blood stream, it can target cells beyond the local area.
which type of hormone diffuses across the plasma membrane and binds to receptors in the cytoplasm?
Steroid hormones diffuse across the plasma membrane and bind to receptors in the cytoplasm.
What is the effect of increased glucagon levels on the amount of glycogen stored in the liver?
Stimulate the conversion of glycogen to glucose in the liver, which in turn decreases the amount of glycogen stored in the liver.
Endocrine Communication
Transmission: Through the blood stream Chemical Mediators: Hormones Distribution of effects: Target cells are mainly in other distant tissues and organs and must have appropriate receptors.
Identify the 2 regions of an adrenal gland, and cite the hormones secreted by each.
The cortex and the Medulla -The cortex secrets Mineralcorticoids, alsosterone, Glucocorticoids, Cortisol, Corticosterone, Cortisone. -The Medulla secrets Eninephrine and norepinephirine
In the hypothalamus and pituitary gland the portal vein is apart of what?
The hypothalamo-hypophyseal portal system.
Neurons within specific nuclei (collections of neurons) in the hypothalamus send their axons into the posterior lobe of the pituitary gland where they release hormones at capillary beds. Where does the release of hormones go?
The released hormones then travel in the systemic circulation to have influences on cells, tissues and systems in other parts of the body.
In the hypothalamus and pituitary gland the inflow of blood comes from where?
The systemic circulation.
Hormones secreted by the anterior pituitary under the influence of the hypothalamus then are distributed where?
Through systemic circulation to cells in target endocrine glands throughout the body.
where is the thyroid gland located?
anterior surface of the trachea just inferior to the thyroid cartilage of the larynx.
decreased blood circulation levels would result in increased secretion of which hormone
decreased blood calcium levels result in increased secretion of PTH.
diabetes mellitus
glucose concentrations that are high enough to overwhelm the reabsorption capabilities of the kidneys.
Hormone secretion is controlled through what?
negative feedback mechanisms.
Explain how parathyroid hormone increases blood calcium levels.
parathyroid hormone (PTH) increases blood calcium levels by decreasing calcium deposition in bones, by increasing reabosorption of calcium from the blood by the kidneys, and by increasing the production of calcitriol by the kidneys.
What is the common goal of the nervous and endocrine systems?
perserve homeostasis by coordinating and regulating the activities of other cells, tissues, organs and systems.
Identify the hormone-secreting cells of the pineal gland.
pinealocytes
describe the location of the parathyroid glands
posterior surface of the adrenal gland
hormone receptor
protein molecule located either on the plasma membrane or inside the cell, that binds to a specific hormone.
pituitary gland
releases hormones under the influence of the hypothalamus' control that control the secretory glands elsewhere in the body.
Parathyroid glands
secrete a hormone important to the regulation of calcium ion levels in body fluids.
adrenal glands
secrete hormones involved with mineral balance, metabolic control, and resistance to stress. Adrenal medulla release epinephrine and norepinephrine during sympathetic activation.
When blood glucose levels fall, other pops. of cells in the pancreas secrete glucagon
which stimulaes glycogen breakdown and glucose release by the liver.
When blood glucose levels increase, cells in the pancreas secrete insulin
which stimulates glucose transport of glucose across cell membranes.
