Anatomy 2 Exam 1 (endocrine system)

What is the endocrine system composed of?

• Hormones

• Target cells that bind to hormones

What is the 4 step proceses of hormones being transported to target cells?

• Released into interstitial fluid and then enter blood

• Transported within blood

• Randomly leave blood and enter interstitial fluid

• Hormone binds to target cell receptors

What are the similarities and differences of the endocrine system and the nervous system?

Similar:

• Release ligands/chemical messengers that bind to receptors

Difference:

• Endocrine:

  • transmits hormones through blood

  • Target and cells in body with correct receptors

  • Longer reaction time

  • last longer

What are the 4 general functions of the endocrine system?

• Regulating development, growth, and metabolism

• Maintaing homeostasis

• Controlling digestive processes

• Controlling reproductive activities

Define hormonal, humoral, and nervus stimuli?

• Horm: A gland cell releases its hormone when some other hormone binds to it

• Hum: A gland cell release its hormone when there is a certain change in levels of a nutrient or ion in the blood

• Nervous: A gland releases its hormone when a neuron stimulates it

Define the 3 circulating hormones?

• Steroids:

  • Lipid soluble

  • Ex, estrogen

• Biogenetic amines:

  • Modified amino acids

  • Ex: melatonin and thyroid hormone

• Proteins:

  • All other hormones

  • Water soluble chains of amino acids

What is the difference between lipid soluble and water soluble?

• Lipid is hydrophobic while water is hydrophilic

• Water soluble has a shorter half life when not attached to carrier protein

• Lipids can pass through membrane and are lipophillic

• Lipids only have a protein product cellular responce

• Water soluble has chemical reactions, membrane permeability and muscle contraction

What are local hormones?

• Signaling molecules that don’t circulate in the blood

• Ex: Prostaglandins (anti-inflamatory)

Define autocrine and paracrine stimulation

• Auto: Bind to the cells that release them

• Para: Bind to neighboring cells

Lipid soluble hormone sequence

• Defuses across target membrane

• Attach to receptors in cytosol or nucleus

• This form a hormone-receptor complex

• Complex binds to a hormone-responce element of DNA

• Results into a protein

Water soluble hormone sequence (Signal transduction pathway)

• Attaches to membrane receptors (first messenger)

• Binding activates G-protien

• Results in binding of GTP (membrane enzyme)

• Example: adenylate cyclase

Describe up-regulation and down-regulation

• Up:

  • Increases number of receptors

  • Increases sensitivity to hormone

  • When blood levels are low

• Down:

  • Decreases number of receptors

  • Decreases sensitivity to homone

  • When blood levels are high

Describe and give examples of synergistic, permissive and antagonistic interactions on a target cell

• Syn:

  • One hormone reinforces activity of another hormone

  • Ex; estrogen and progesterone

• Per:

  • One hormone requires activity of another hormone

  • Ex: Oxytocins milk ejection effect requires prolactin

• Ant:

  • One hormone opposes activity of another hormone

  • Ex: Glucagon increases blood glucose while insulin lowers it

What hormones does the posterior pituitary store/release and their functions?

• Antidiuretic hormone (ADH)

  • decrease urine production, stimulate thirst, constrict blood vessels

• Oxytocin (OT)

  • Uterine contraction, milk ejection, emotional bonding

What are the 5 releasing hormones and 2 inhibiting hormones of the hypothalamus?

• Releasing:

  • thyrotropin-releasing hormone (TRH)

  • prolactin-releasing hormone (PRH)

  • gonadotropin-releasing hormone (GnRH)

  • corticotropin-releasing hormone (CRH)

  • growth hormone-releasing hormone (GHRH

• Inhibiting:

  • Prolactin-inhibiting hormone (PIH)

  • Growth-inhibiting hormone (GIH)

What are the 6 hormones of the anterior pituitary?

• Thyroid-stimulating hormone (TSH)

• Prolactin

• Adrenocortitropic hormone (AcTH)

• Growth Hormone (GH)

• Gonadotropins/ Follicule stimulating hormone (FSH)

• Luteinizing Hormone (LH)

Thyroid Stimulating Hormone Cycle/steps

Prolactin cycle/steps

Adrenocorticotrpoin Hormone (AcTH)

Growth Hormone (GH) cycle/steps

What does the GH cause the liver to secret?

• Insulin like growth factors 1 and 2

Gonadotropin/follicle stimulating hormone (FSH) and luetenizing hormone (LH) cycle/steps

What are the 3 disorders of the growth hormone and their definitions?

• Growth hormone deficiency:

  • Inadequate growth hormone production

  • Due to hypothalamic or pituitary problem

  • Short stature and low blood sugar

• Pituitary gigantism:

  • Too much growth hormone

  • Excessive growth and increased blood sugar

  • Enormous internal organs

  • Death at early age if untreated

• Acromegaly:

  • Excessive growth hormone production in adult

  • Enlargement of bones of face, hands, and feet

  • Increased release of glucose

  • Internal organs increased in size

  • Results from loss of feedback control of growth hormone

What cells is the thyroid gland composed of?

• Follicular cells:

  • synthesize thyroglobulin (TGB)

  • Produce/release thyroid hormone (TH)

  • Surrond a central lumen

• Parafollicular cells:

  • Make calcitonin

  • Hormone decreases blood calcium levels

What are the steps of the thyroid hormone syntheses, storage and release?

• Cold temperature trigger’s hypothalamus to release TRH

• Anterior pituitary release TSH

• TSH binds to follicular cells and triggers release of TH

• Follicular cells release 2 forms of TH: T3 and T4

What are the 3 disorders of the thyroid hormone and their definitions/treatments

• Hyperthyroidism:

  • To much excessive TH

  • Increased metabolic rate, weight loss, hyperactivity, heat tolerance

  • Remove the thyroid to treat

• Hypothyroidism:

  • Decrease in TH

  • Low metabolic rate, lethargy, cold intolerance, weight gain

  • Thyroid hormone replacement to treat

• Goiter:

  • Enlargement of thyroid

  • Lack of iodine

  • Fixed by iodine in table salt

What is calcitonin regulation and effects?

• Stimulus is high blood calcium or stress

• Parafollicular cells release calcitonin

• Decreases blood calcium levels by

  • Inhibiting osteoclast activity

  • Stimulate kidneys to increase excretion of calcium in urine

What are the parathyroid glands and what cells do they contain?

• Small structures in the posterior surface if the thyroid gland, usually 4 of them

• Contain chief cells that make parathyroid hormone (PTH)

What does the PTH do?

• Increases blood cacium

What are the 2 regions of the adrenal gland and what do they do?

• Adrenal medulla:

  • releases epinephrine and norepinephrine

• Adrenal cortex:

  • Synthesizes more than 25 corticosteroids

What are the 3 regions of the andrenal cortex and hormones made in them?

• Zona glomerulosa

  • Mineralocorticoids, regulate electrolyte levels

  • Aldosterone

• Zona fasciculata

  • Glucocorticoids, regulate blood sugar

  • Cortisol

• Zona reticularis

  • Gonadocoticoids, sex hormones

  • Androgens, male sex hormones that is concerted to estrogen in females

What is cortisol and its regulation/effects

• Increases nutrient levels in blood

• Resist stress and repair injured tissue

• Makes body more alert

• Cortisol increases in sleep and stress

• Long term solution

• Stress stimulates hypothalamus to releases CRH —> CRH stimulates anterior pituitary to release ACTH —> ACTH stimulated adrenal cortex to release cortisol

What are the disorders in adrenal cortex hormone secretion

• Cushing disease:

  • to much glucocorticoid

  • Obesity, hypertension, excess male-pattern hair growth kidney stones, and menstral irregularities

• Addison disease

  • Not enough glucocortiods made

  • Weight loss, fatique and weakness, hypotension, and skin darkening

Describe acinar cells and pancreatic cells within the pancreas

• Acinar:

  • Generate exocrine secretions for digestion

  • Make up majority of pancreas as saclike acini

• Pancreatic cells

  • contain clusters of endocrine cells like alpha cells and beta cells

Alpha cells in the pancreas secrete?

• Glucagon

Beta cells in the pancreas secrete?

• Insulin

Pancreatic hormones do what?

• Lower high blood glucose levels with insulin

• Raising low blood glucose levels with glucagon

What are the 4 conditions resulting in abnormal glucose?

• Diabetes mellitus

  • inadequate uptake of glucose from blood

• Type 1 diabetes

  • Absent of diminished release of insulin

  • Requires daily injections of insulin

• Type 2 diabetes

  • Decreased insulin release or effectiveness

  • diet, exercise and medications can help

• Gestational diabetes

  • seen in pregnent women

  • if untreated, causes risk to fetus and increases delivery complications

What does the pineal gland do?

• Secretes melatonin

What does the thymus do?

• Secretes thymic hormones which is where t-cells mature before entering the blood

What does the endocrine tissue in the heart do?

• Secretes atrial natriuretic peptide that lowers blood pressure

What do the kidneys secrete?

• Eyrthropetin (EPO) that is secreted when there is low blood oxygen to increase red blood cell production

What does the liver secrete?

• Insulin-like growth factors and yhe inactive hormone angiotensinogen

  • increases blood pressure

What does the stomach secrete?

• gastrin that increases secretion and motility for digestion

• Goes into blood then back into stomach to actiavte

What does the small intestine secrete?

• Secretin and cholecystokinin into blood

  • Stimulates secretion of bile and pancreatic juice

What does the skin do in the endocrine system?

• In skin cells, light converts modified cholesterol to Vit D that is released into the blood

• Increases calcium absorption in the intestine

What does adipose connective tissue secrete?

• Leptin that controls appetite

What happens to the endocrine system as you get older?

• It reduces function