Chapter 16- Anatomy 2
Chapter 16, LO #1: Compare and contrast how the endocrine and nervous system control body functions
-endocrine: organs of this complex system work by synthesizing and secreting chemical messengers called hormones: which interact with target cells and influence their function to maintain fluid, electrolytes, and acid-base homeostasis, promotes growth,and regulate metabolic reactions... not close to direct contact instead are secreted into the bloodstream where they travel to target cell...can take hours of day, long-lasting -nervous: works through neurons that directly affect their target cells through release of neurotransmitters... effects are immediate and short-lived unless stimulation if repetitive NS and ES work together to maintain almost all aspects of homeostasis; cells from both systems use chemicals to communicate (but NS also uses electrical signal)
Chapter 16, LO# 15, Discuss the gross and microscopic anatomy of the thyroid gland, including the types of cells within the thyroid that produce calcitonin and thyroid hormone. Describe the stimulus for release, the target tissue, and the functional effect of thyroid hormone and calcitonin.
Thyroid secretes thyroid hormone (TH) and calcitonin, located on anterior neck, butterfly-shaped gland consists of right and left lobes connected by isthmus (small band of thyroid tissue). Microscopically, the gland is composed of multiple spheres called thyroid follicles; follicle cells found at the outer edge of follicles produce and secrete thyroid hormones. colloid: protein-rich, gelatinous material that contains precursor for thyroid hormone and high concentration of iodine atoms; both important to thyroid hormone synthesis. parafollicular cells: in spaces between adjacent thyroid follicles; large cells that produce the hormone calcitonin -thyroid hormone consists of an amino acid core bound to either 3 T3 and T4- t3 and 4 are physiologically active but T3 is much greater so T4 commonly converted in T3 in some target tissue, both amino acid-based hormones although they are an exception in that they are more hydrophobic than other amino-acid based hormones, do not interact with PM bound receptors, they enter target cells that either activate or inhibit specific gene transcription effects: almost every cell contains thyroid hormones receptors, 3 categories of effects: regulation of metabolic rate and thermoregulation: TH set basal metabolic rate (amount of energy required by body at rest) by increasing rate of ATP consumption, increasing gluconeogenesis, and by initiating energy- requiring reactions in these same target cells; heat is generated, which is critical for core body temp homeostasis -promotion of growth and development: required for normal bone growth, muscle growth, and nervous system development -synergism with sympathetic nervous system: increase of TH levels act on target cells of SNS and increase (up-regulate) receptors for sympathetic neurotransmitters; affects regulation of blood pressure, heart rate, and other sympathetic activities
Chapter 16, LO #19, Describe the stimulus for release, the target tissue, and the effects of the catecholamines produced by the adrenal medulla. Explain the relationship of the adrenal medulla to the sympathetic nervous system
chromaffin cells (derived from nervous tissue) secrete mostly epinephrine (a catecholamine); mediate immediate responses to a stressor, increase rate and force of heart contractiion and dilate bronchioles in lung, constrict blood vessels supplying skin, digestive organs, and urinary system (increasing blood pressure), dilate blood vessels supplying skeletal muscle, dilate pupils and decrease digestive and urinary functions -catecholamines in bloodstream prolong short-lived effects of neurotransmitters catecholamine; can also reach cells not innervated by sympathetic system, regulation of adrenal medulla includes SNS and HPA axis: ACTH can stimulate epinephrine release; cortisol increases synthesis of enzymes that produce catecholamines, overall result is a coordinated, integrated response between endocrine and NS; increases our change for survival in face of a stressor
Chapter 16, LO #3: Define endocrine gland (organ). List both the primary and secondary organs of the endocrine system
endocrine gland: diverse groups of organs found throughout the body; regulates cell type by secreting hormones, ductless and secreted into ECF and transported through the bloodstream: primary: have an only endocrine function (ex.: anterior pituitary gland, thyroid, parathyroid, adrenal cortices, endocrine pancreas, thymus) secondary: have both endocrine and a variety of non-endocrine functions (ex.: heart, kidneys, and small intestines, testes, ovaries... neuroendocrine: hypothalamus, pineal gland, adrenal medulla)
Chapter 16, LO #8: Discuss the role of negative feedback loops in controlling hormone production
feedback loops: regulate hormone occur in the following sequence: stimulus: a regulated physiological variable deviates from its normal range -receptors; these on target cells detect deviation of variable -control center: stimulated control center (often endocrine cell) increases or decreases its secretion of a particular hormone -effector/ response: hormone triggers a response in its target cells that moves conditions toward normal range -homeostatic range: as variable returns to its normal range, feedback to control center decreases response...negative feedback = positive things, self-correcting
Chapter 16, LO #9: Define 3 hormone interactions including complementary action, synergists, and antagonists
hormone interaction- maintenance of homeostasis requires multiple hormones: -complementary action: each hormone interacts with a different target cell in order to accomplish a common goal -synergist: can act on same target cell to exert same effect, more pronounced with interaction of multiple hormones than any one individual hormone by itself -antagonists: act on same cells but have opposite effects
Chapter 16, LO #4: Define hormones and discuss their characteristics and function. Be sure to include their interactions with receptors and target cells
hormones: are chemical messengers secreted by endocrine glands that regulate functions of other cells 4 features of hormones: hormones cause widespread in seconds of hours, travel unbound chemical in blood or bound attached to plasma protein carriers, continue in the bloodstream until taken up by target cells or broken down and deactivated target cells: hormones are able to affect only particular cells called these receptors: target cells contain specific proteins ______ to which hormones bind.. can be embedded in the plasma membrane or reside within cytosol or nucleus of a target cell
Chapter 16, LO #13, Explain how the hypothalamus controls the anterior pituitary by using releasing and inhibiting hormones. List the 5 releasing and 2 inhibiting hormones produced by the hypothalamus
hypothalamus controls many functions of anterior pituitary: hypothalamus produces and releases tropic hormones that either stimulate (releasing hormones), or inhibit (inhibiting hormones) release of hormones from anterior pituitary, tropic hormones travel from hypothalamus to anterior pituitary by hypothalamic- hypophyseal portal system, many anterior pituitary hormones are also tropic; control secretion of hormones by various endocrine glands in body -5 releasing hormones: thyrotropin- releasing (TRH), corticotropin- releasing(CRH), prolactin- releasing (PRH), gonadotropin- releasing (GnRH), growth hormone-releasing (GHRH) -2 inhibiting hormones: somatostatin, prolactin-inhibiting factor... they keep normal levels by negative feedback loop in tiers of control and is critical.. hypothalamus, anterior pituitary, involves actions of anterior pituitary hormones at target tissues... hypothalamus stops releasing tropic hormones when the normal range is back
Chapter 16, LO #12, Describe the stimulus for release, the target tissue, and the functional effect of the 2 neurohormones released by the posterior pituitary
no hormones are actually made in the posterior pituitary but 2 neurohormones are produces by hypothalamus and stored and released there: anti diuretic hormone (ADH) and oxytocin -ADH: water retention, aka as vasopressin and it controls water balance, continually produced in low amounts by hypothalamus transported through axon in infundibulum to axon terminal in post pituitary stored in synaptic vesicles. the terminals do not have synapses instead release, instead release ADH into blood vessels when stimulated by action potentials... ADH allows for insertion of water channels (aquaporins) into PM of cells that make up kidney tubules, water passes into cytosol of these cells, then back into ECF and finally to blood; would otherwise have been eliminated from body in urine -ocytocin: produced by hypothalamus and stored in axon terminal of posterior pituitary gland, primary focused on reproduction, target cells are in mammary glands of breast tissue and smooth muscle of uterus, in nursing sucking stimulates this hormone causing milk ejection.. milk let-down reflex: example of positive feedback ; sucking induces lactation causing more sucking and more milk release, loop ceases when sucking stops
Chapter 16, LO #21, Describe the target tissue, and the effects of the hormones produced by the pineal and thymus glands
pineal gland: primary endocrine; component of epithalamus (posterior region of diencephalon of brain): secretes neurohormone melatonin, appears to be related to light and dark cycles; secretion increases in dark, melatonin's main target tissues are sleep-regulation centers in reticular formation of brainstem; appears to adjust sleep/wake cycle in some individuals -thymus: primry endocrine gland found in the mediastinum, location where T lymphocytes mature, secretes hormones thymosin and thymopoietin; function mainly as paracrine signals that assist in T lymphocyte maturation
Chapter 16, LO #7: Discuss the 3 types of stimuli that control the production and secretion of hormones
secretion can be initiated or inhibited by 3 different stimuli: -hormonal stimuli:some endocrine cells increase or decrease their secretion in response to secretion of other hormones -humoral stimuli: many endocrine cells respond to concentration of a certain ion or molecule in blood or ECF, comes from drugs we take sometimes, chemicals in blood stream -neural stimuli: some endocrine cells respond to signals from NV
Chapter 16, LO #22, Describe the target tissue, and the effects of the hormones produced by the gonads, adipose tissue, the heart, and the kidneys
testes and ovaries are reproductive gonads, responsible for gametes, produce sex steroid hormones responsible for gamete production and other functions -testes produce testosterone (females make testosterone in adrenal glands); production and secretion in regulated by a multi- tiered negative feedback loop; GnRH triggers secretion of LH and FSH; LH stimulates testosterone and synthesis and FSH stimulates production of a protein that binds testosterone and concentrated it in testes, elevated blood levels of testosterone inhibit GnRH secretion, which closes the loop, is hydrophobic, binding to intracellular receptors that influence expression of various genes, has anabolic effects, which include those that stimulate bone growth and increase muscle mass, has androgenic effects, which encompass those involving development of male secondary sex characteristics -cells of ovary female sex hormones, estrogen nd progesterone: estrogen: males produce a small amount of estrogen in adrenal glands, multi-tiered negative feedback loop involving hypothalamus and anterior pituitary provides regulatory control; similar to testosterone regulation, estrogen stimulates development of secondary female sex characteristics, regulates the trual cycle, and has multiple effects on other tissues and organs -progesterone: secretion peaks after ovulation and during pregnancy; physiological effects include body preparation for pregnancy and support of fetal development during pregnancy, also has effects on smooth muscle tissue, body temp, blood clotting, bone tissue, and metabolism
Chapter 16, LO #2: Explain the different types of chemical signaling used by the body
three types of chemical signaling used by the body: hormones (affects different cells types and distant cells) and neurotransmitters represent only a few types paracrine: chemicals are secreted by cells into ECF space to affect nearby but different type of cells autocrine: chemicals are secreted by cells into interstitial fluid; effects from same cell or cell type
Chapter 16, LO #10, Differentiate between tropic and trophic hormones. Be able to give examples of each
tropic hormone: control secretion of hormones from other endocrine glands, one hormone induces other hormones trophic hormone: induce growth in target cells, note that some hormones have both tropic and trophic effects on target cells- cause enlargement of organ
Chapter 16, LO #5: Describe hydrophilic and hydrophobic... up-regulation and down-regulation
-hydrophilic: hormones cannot readily cross the plasma membrane so generally interact with receptors found embedded in the target cell's plasma membrane, flows freely, not able to get into the plasma membrane, mixes with water, easy transport- difficult access. receptors activate a peripheral protein, and it activates an enzyme, then enzyme catalyzes the formation of the second messenger which initiates a series of events in the cell that leads to change inactivity -hydrophobic: hormones are able to cross through the plasma membrane so generally interact with receptors found in the cytosol or nucleus, does not mix with water, difficult transport, easy access. forms a complex with its receptor; generally, interact with the DNA of target cell, this exerts its effects y changing the rate of protein synthesis by one or more proteins number of receptors: they have to be healthy for everything to work: -up-regulation: the process by which target cells produce and display a greater number of receptors in response to a temporary increase in hormone level in the blood -down-regulation: the process by which target cells decrease the number of receptors displayed in response to prolonged exposure to a high level of hormone in the blood
Chapter 16, LO #6: Describe the 2 major chemical classes of hormones found in the human body and list the effects of hormone action
2 major chemical classes of hormones in human body are: -amino acid hormones: consists of 1 or more amino acids ranging in size from solitary amino acids to multiple (peptide hormones); generally hydrophilic, binding to plasma membrane receptors, can't go inside cell -steroid hormones: derived from cholesterol; hydrophobic hormones that bind to receptors in cytosol or nucleus, has to have a carrier that is bound effects of hormone actions: stimulating secretion from an endocrine or exocrine cell, activating or inhibiting enzymes, stimulating or inhibiting mitosis and/or meiosis, opening or closing ion channels in cell's plasma membrane and/or altering its membrane potential, activating or inhibiting transcription of genes that code for RNA or proteins (gene expression)
Chapter 16, LO #22, Describe the target tissue, and the effects of the hormones produced by the gonads, adipose tissue, the heart, and the kidneys: PART TWO
adipose tissue: adipocytes produce protein hormone leptin; able to cross blood-brain barrier where it ineteracts with neurons in hypothalamus, its main target tissue, action of leptin is to induce satiety, which prevents overfeeding, leptin production is closely related to adipose tissue quantity; only a component in complex mechanismsd that regulate feeding -the heart: specific cardiac muscle cells contain stretch-sensitive ion channels that open more widely when blood volume inside heart increases; stimulates cardiac muscle cells to secrete atrial natriuretic peptide (ANP): triggers relaxation of smooth muscle cells in blood vessels; increases vessel diameter (vasodilation), enhances excretion of Na from kidneys, an effect calledd natriuresis; enhances water excretion from kidneys; creates a concentration gradient that water follows into kidney fluid by osmosis, both effects, vasodilation and natriuresis, decrease blood volume and lower blood pressure -kineys: serve following roles involving endocrine functions erythropoietin (EPO): secreted by specific kidney cells in response to decreases blood oxygen levels; acts on red bone marrow to stimulate development of new erythrocytes (erythrooiesis); increases oxygen-carrying capacity of blood, specific kidney cells secrete renin; converts plasma protein angiotensinogens to angiotensin I; vital component of renin-angiotensin-aldosterone system, which maintains blood pressure, vitamin D made in response to sunlight in skin is converted to its active form in kidneys under influence of parathyroid hormone. activated Vitamin D-calitriol
Chapter 16, Lo #17, Describe the gross and microscopic anatomy of the cortex and medulla of the adrenal gland
adrenal glands: located on superior aspect of each kidney; roughly pyramid-shaped; produce catecholamine and steroid hormones... divided into outer adrenal cortex surrounding inner adrenal medulla. cortex;typical endocrine gland with similar functions to those previously discussed , is further divided into three distinct zones, each of which produces steroid hormones derived from cholesterol medulla: neuroendocrine organ that secretes neurohormones
Chapter 16, LO# 14, Describe the stimulus for release, the target tissue, and the functional effect of each of the 6 anterior pituitary hormones. Discuss the production of insulin- like growth factors and the role they play throughout life
anterior pituitary hormones that affect other glands: tropic hormones secreted by anterior pituitary include: -thyroid- stimulating hormone (TSH): stimulates development of thyroid gland and its secretions, (thyroid hormone); TSH release is stimulated by hypothalamic hormone thyrotropin-releasing hormone -adrenocorticotropic hormone (ACTH, corticotropin) stimulates development of adrenal gland and synthesis of various steroid hormones; ACTH release is stimulated by hypothalamic hormone CRH -prolactin PRL: stimulates growth of mammary glands tissue, initiates milk production and maintains milk production, it is stimulated by hypothalamic hormone prolactin releasing hormone nd prolactin-inhibiting factor known as dopamine -luteinising hormone (LH; gonadotropin): male: stimulates production of testosterone by testes under direction of hypothalamic hormone GnRH... female: stimulates production of estrogen and progesterone from ovaries; triggers release of an oocyte in process of ovulation; also under direction of GnRh -follicle- stimulating hormone (FSH; gonadotropin): male: stimulates cells of testes to produce chemical tat bind and concentrate testosterone; under direction of GnRH...female: FSH and LH together trigger production of estrogen; FSH also triggers maturation of ovarian follicles (house developing oocytes) -growth hormone (GH, somatotropin): produced and secreted by somatotropin; release GH periodically throughout day, with peak secretion occurring during sleep... main function is to regulate growth of various target tissues including skeletal and cardiac muscle, adipose, liver, cartilage, and bone; can be either short or long-term effects... short term effects- generally metabolic; include promotion of fat breakdown, generation of new glucose in liver, and inhibition of glucose uptake by muscle fibers, all of which increase blood glucose and fatty acid levels; can be used by cells for fuel and raw materials for growth -long-term effects: are not all directly mediated by GH: GH acts on the liver and other target tissues to promote production of hormone, insulin- like growth factor (IGF): affects nearly every cell in body; triggers rapid protein synthesis and cell division leading to increased longitudinal bone growth and muscle development in children... decreases blood glucose ("insulin-like") concentration in blood by stimulating glucose uptake by cells; in opposition to initial actions of GH. GH+ IGF continue to play important roles in adults, such as promoting muscle development as well as regulation of body mass
Chapter 16, LO #11, Describe the location of, as well as the anatomical and functional relationships between the hypothalamus and the anterior/ posterior pituitary glands
hypothalamus, "the boss", regulation of thirst, hunger, fluid balance, body temp, sleep/wake cycle, and certain reproductive functions, anatomical and functional relationship between the hypothalamus and pituitary gland is important to homeostatic regulation, some hypothalamic functions are performed directly by neurons that terminate in posterior whereas other hormones target anterior pituitary, target organ: always pituitary gland... hypothalamus- a small anteroinferior portion of diencephalon connected to the pituitary gland by a stalk called the infundibulum. -pituitary gland: the l organ that sits in the sella turcica of sphenoid bone; composed of following two structurally and functionally distinct components -anterior pituitary (adenohypophysis)- true gland composed of hormone-secreting glandular epithelium -posterior pituitary (neurohypophysis): made up of nervous tissue hypthalmic- hypophyseal portal system- 2 sets of capillaries beds, specialized blood supply; allows both hypothalamus and pituitary to deliver their hormones directly to target cells, capillaries merge in the thalamus to form portal veins that travel through the infundibulum then lead to second group of capillaries in the anterior pituitary.. these type of systems that go from capillaries that are drained by veins that lead to another set of capillaries are called portal systems
Chapter 16, LO #20, Describe the structure of the endocrine pancreas and its hormone-secreting cells. Describe the stimulus for release, the target tissue, and the effects of glucagon and insulin. Explain how they work together to maintain healthy blood glucose levels...PART TWO
insulin: primary antagonist of glucagon; produced ad secreted from beat cells of pancreatic islet; stimulates following responses in target cells (liver, cardiac muscle, skeletal muscle, and parts of brain). promotes up-take and storage of ingested nutrients (lipids, amino acids, and glucose); lowers blood glucose levels, synthesis of glucagen in liver; synthesis of fat from lipids and carbs, promotes satiety (feeling of fullness), insulin and glucagon are antagonists in a complicated feedback loop that maintain blood glucose homeostasis following feedback responses are initiated when blood glucose level decreases, stimulus: blood glucose level decreases below its normal range, receptor: alpha cells of pancreas detect decreased blood glucose concentration, as well s presence of ingested protein, control center: alpha cells increase glucagon secretion; beta cells decrease insulin secretion -feedback responses to decreased glucose levels effector/ response: glucagon triggers breakdown of glycogen (glycogenolysis) into glucose and formation of new glucose (gluconeogensis), homeostatic range and negative feedback- as blood glucose level returns to its normal range, negative feedback to lpha cells decreases glucagon secretion
Chapter 16, LO #18, Describe the stimulus for release, the target tissue, and the effects of the mineralocorticoid, glucocorticoids, and androgenic steroids produced by the 3 zones of the adrenal cortex
outer zona glomerulosa consists of densely packed cells that produce mineralocorticoid hormones, zona fasciculata consists of cells stacked on one another in columns secretes glucocorticoid and androgenic steroids, zone reticularis thin layer of cells arranged loosely in clusters; secrete glucocorticoids and androgenic steroids -aldosterone: the main mineralocorticoid, regulates concentration of certain minerals (K and Na) in body, maintains concentration of extracellulr sodium and K ions within normal ranges, regulates ECF volume, maintains blood pressure through interactions called renin-angiotensin- aldosterone system(RAAS), maintains acid-base homeostasis -glucocorticoids: produced in zona fasciculata and reticularis; the main role is to help mediate body's response to stress; cortisol (hydrocortisone)from the zona fasciculata is most potent glucocorticoid -stress response: involves regulation of blood glucose levels and: cortisol stimulates liver cells to synthesize enzymes involved in gluconeogenesis (production of new glucose molecules from amino acids and fatty acids) increases blood glucose levels , induces breakdown of proteins in skeletal muscle; releases free amino acids into blood that can be convertedd to glucose by gluconeogenesis, acts on adipocytes to release fatty acids into blood; can be convertedd into fuel in liver, these receptors are found in cells throughout body such that actions of this steroid hormone are widespred; hormone is a potent anti-inflammatory that decreases levels of certain leukocytes -androgenic steroids: steroid sex hormone that affect reproductive organs (gonads) as well as other tissues, adrenal cortex synthesizes these hormones in mall quanitites in both genders; largely byproducts of cortisol synthesis pathway, same general effects are those made by gonads, can be converted in circulation to androgen testosterone or femal estrogen
Chapter 16, LO #20, Describe the structure of the endocrine pancreas and its hormone-secreting cells. Describe the stimulus for release, the target tissue, and the effects of glucagon and insulin. Explain how they work together to maintain healthy blood glucose levels
pancreas: club- shaped organ located in abdominal cavity, mostly posterior to stomach; consists of 3 major regions: a rounded head, body, and thin tail..both endocrine and exocrine -pancreatic islets (islets of Langerhans): small rounded islands populated by endocrine cells; secrete hormones into bloodstream.. contain 3 cell types: alpha cells: secrete peptide hormone glucagon, bet cells: secrete protein hormone insulin, delta cells: secrete peptide hormone somatostatin -exocrine acinar cells: clustered around small ducts into which they secrete enzymes and other products that are delivered to digestive tract -glucagon and insulin regulate concentration of glucose in blood; glucagon: produced and secreted from alpha cells in pancreatic islets; major target tissues are cells of liver, muscle tissue, and adipose; promotes reactions that increase levels of glucose and metabolic fuels in blood; initiates: breakdown of glycogen (glycogenolysis), formation of new glucose in liver, breakdown of proteins in musle tissue to release amino acids for gluconeogenesis, release of fats from adipose tissue from gluconeogenesis and for additional cellular fuels, formation of fuel molecules called ketone bodies in liver.. -ketone bodies: four- carbon molecules formed during fatty acid metabolism; released into bloodstream and taken up into skeletal muscle and cardiac muscle cells, these cell types are able to oxidize ketone bodies for fuel, unlike liver cells, during starvation glucagon promotes rapid ketone body formation; overwhelms capability of cells to use them and they accumulate in blood
Chapter 16, LO #16, Discuss the gross and microscopic anatomy of the parathyroid gland, including the types of cells within the parathyroid that produce PTH. Describe the stimulus for release, the target tissue, and the functional effect of PTH (parathyroid hormone)
parathyroid glands: typically 3-5 separate glands; posterior surface of the oid gland; secrete PTH from chief cell -calcium ion homeostasis: chief cells secrete PTH and thyroid secretes calcitonin, both have opposing effects on calcium ion concentration in blood; keeps this vital ion within a normal range.. PTH increases blood calcium balance -calcitonin: produced and secreted by parafollicular cells; released which calcium ion level is above normal, primary target is osteoclast cells, this activity is inhibited by the ence of calcitonin; allows osteoblast activity, unopposed osteoblast activity reduces blood calcium ion levels as these ions are incorporated into bone matrix PTH: major factor in maintenance of blood calcium ion levels in blood triggers: increase release of calcium ions from bone by stimulating osteoclast activity. increases absorption of dietary calcium ions by small intestine, acts on kidneys to convert inactive vit. D into active form; increases absorption of dietary calcium ions from small intestine, increases reabsorption of calcium ions from fluid in kidneys