Endocrine System and Hormones

Hypothalamus

- Peptide hormones

- Synthesizes then stores + rel in post pit = Oxytocin + vasopressin

- GnRH to stim ant pit to rel FSH + LH

- reg ant pit hormone releases

Pineal Gland

Amino Acid derive hormones; Melatonin to reg circadian rhythym

Pituitary Gland (Ant)

- Peptide hormones

- FSH to stim spermatogenesis + estrogen rel

- LH to stim testosterone rel + progesterone rel, corpus luteum formation, trig ovulation

- TSH to stim thyroid gland to rel T3 + T4

- ACTH to stim adrenal cortex to rel glucocorticoids

- Prolactin to stim mammary glands to prod milk

- GH to stim bone + muscle growth and various metabolic f(x)

- MSH to stim melanocytes to prod melanin

Pituitary Gland (post)

- Peptide hormones

- Oxytocin to stim uterine contraction, milk ejection, maternal behavior

- Vasopressin (ADH) to prom retention of water by kidneys and hence more concentrated urine

Thyroid Gland

- Thyroid hormones and Peptide hormone

- T3 + T4 to inc metabolic rate, req iodine for synth

- Calcitonin to lower blood calcium level and build up bone

Parathyroid Glands

- Peptide hormone

- PTH to raise blood calcium levels

Thymus

- Peptide hormone

- Thymosin to stim T-lymphocyte dev

Adrenal Glands (Medulla)

- Catecholamines hormones

- Epinephrine/ norepinephrine to raise blood glucose level, inc metabolic activities, alter blood flow to prioritize organs (vasoconstriction)

Adrenal Glands (Cortex)

- Steroid hormones

- Glucocorticoids to raise blood glucose level

- mineralocorticoids (aldosterone) to prom reabsorp of Na+ in kidneys and inc water retention/raise bp

- Cortical androgens or low amounts of testosterone + estrogen

Pancreas

- Peptide hormones

- Insulin to lower blood glucose level + stim glucose storage

- Glucagon to raise blood glucose level + stim glucose production

- Somatostatin to inhib rel of insulin, glucagon, and GI hormones to dec gastric motility

Ovaries

- Steroid hormones

- Estrogen to reg menstrual cycle, prom dev + maintain of female secondary sex characteristics

- Progesterone to maintain early pregnancy + reg uterine lining thickiness

Testes

- Steroid hormones

- Testosterone to supp sperm formation, inc muscle mass, prom dev + maintain of male secondary sex characteristics

Which type of cell signaling synthesizes and secretes hormones into the bloodstream?

endocrine

Which type of cell signaling secretes enzymes into ducts?

exocrine

Sudoriferous, sebaceous, mucus, digestive, and mammary glands are examples of what kind of gland?

exocrine

What is the cell signaling where the target is nearby?

paracrine

What kind of cell signaling utilizes hormone or chemical messengers that bind to receptors on the same cell?

autocrine

What are the 3 categories of hormones?

1. peptide

2. steroid

3. tyrosine derivatives

Which category of hormone is synthesized in the

rough ER and modified in Golgi?

peptide

(Note: acts on surface receptors typically via secondary messengers)

Peptide hormones are soluble in what?

water

(Note: can move freely though blood but can't diffuse well through cell membrane of effector - target cell)

How do peptide hormones enter the target cell?

attach to membrane- bound receptor to trigger an effect

Receptors on target cell may act as what to increase membrane permeability to specific ions?

ion channel

Receptors on the target cell may activate or deactivate what to act as ion channels?

intrinsic membrane proteins

Receptors on target cell may activate what to create a cascade of effects?

intracellular second messenger systems

(Note: hormone is the 'first' messenger, and other chemicals act as the 'second' messenger)

A protein stimulating the production of second messengers is an example of what process?

receptor mediated endocytosis

What kind of gland is the pancreas?

exocrine and endocrine

(Note: it releases digestive enzymes via the pancreatic duct, and insulin + glucagon into blood)

What structure secretes FSH, LH, ACTH, hGH, TSH, and prolactin?

anterior pituitary

(Note: examples of peptide hormones)

Anti-diuretic hormone (ADH) is secreted by what structure?

posterior pituitary

(Note: examples of peptide hormones)

Glucagon and insulin are secreted by what structure?

pancreas

(Note: examples of peptide hormones)

Which category of hormone is synthesized from cholesterol in the smooth ER, are hydrophobic, and have intracellular receptors?

steroid

What is the process called when a steroid hormone diffuses into a cell and activates a portion of DNA?

direct stimulation

glucocorticoids and mineralocorticoids (cortisol

and aldosterone) are secreted by what structure?

adrenal cortex

(Note: examples of steroid hormones)

estrogen, progesterone, and testosterone are produced by what structure?

gonads

(Note: examples of steroid hormones - estrogen and progesterone are also secreted by the placenta)

Which category of hormones are formed by enzymes in cytosol or on the rough ER?

tyrosine derivatives

Which tyrosine derivative hormones are lipid-soluble, require a protein carrier in the blood, and bind to receptors in the nucleus?

thyroid hormones

What is the time frame of thyroid hormone action?

The response has a latent period and increased duration

What is the function of thyroid hormones in the body?

increase transcription of many genes in nearly all cells of the body

Which type of tyrosine derivative includes epinephrine and norepinephrine that are water-soluble, dissolve in blood, bind receptors on the target tissue, and mainly act via second messenger cAMP?

catecholamines

T3 and T4 (thyroxine) are which type of hormones?

thyroid hormones

How can hormone regulation occur with respect to receptors?

increasing or decreasing the number of receptors in response to hormone amount

What is the kind of feedback mechanism where the effector is the control point?

negative feedback

(Note: not the concentration of the hormone)

Which endocrine gland monitors the external environment and internal conditions of the body?

hypothalamus

The hypothalamus contains neurosecretory cells that link the hypothalamus to what structure?

pituitary gland

(Note: considered the link between the endocrine and nervous system)

How does the hypothalamus regulate the pituitary?

1. negative feedback mechanisms

2. secretion of releasing and inhibiting hormones.

ADH (vasopressin) and oxytocin to be stored in the posterior pituitary are secreted by what structure?

hypothalamus

Gonadotropin-releasing hormone (GnRH) from neurons, which stimulates the anterior pituitary to secrete FSH and LH are secreted by what structure?

hypothalamus

What structure mainly regulates hormone production by other glands, and is regulated itself by the hypothalamus?

anterior pituitary

What type of hormones directly stimulate target organs?

direct (non-tropic) hormones

Which direct (non-tropic) hormone stimulates milk production in females from mammary gland cells?

prolactin

What can inhibit prolactin release?

hypothalamus

Suckling stimulates the hypothalamus, which stimulates what structure to release prolactin?

anterior pituitary

Which direct (non-tropic) hormone stimulates melanocytes to produce and release melanin?

melanocyte stimulating hormone (MSH)

Which type of hormone stimulate other endocrine glands?

tropic hormones

Which tropic hormone stimulates adrenal cortex —> release glucocorticoids via second messenger cyclic AMP?

ACTH

Which tropic hormone stimulates the thyroid gland which in turn increases in size, cell number, and rate of secretion of hormones T3 and T4?

thyroid stimulating hormone (TSH)

T3 and T4 concentrations have what kind of effect on TSH release?

negative feedback effect

(Note: at both the anterior pituitary and hypothalamus)

Which tropic hormone in females, stimulates the formation of the corpus luteum, and in males, stimulates testosterone production?

luteinizing hormone (LH)

Which tropic hormone in females, stimulates estrogen secretion, and in males, stimulates maturation of seminiferous tubules and sperm production?

follicle stimulating hormone (FSH)

What structure does not synthesize hormones, but stores ADH and oxytocin produced by the hypothalamus?

posterior pituitary

What hormone increases the reabsorption of water by increasing the permeability of the nephron's collecting duct, which leads to water reabsorption and increased blood volume and pressure?

anti-diuretic hormone (ADH/vasopressin)

Coffee and alcohol block ADH, therefore resulting in what effect?

increasing urine volume

Which hormone is secreted during childbirth, increases the strength of uterine contractions, and stimulates milk ejection?

oxytocin

How do hormones travel from the hypothalamus to the posterior pituitary and into the blood?

Neural cell bodies of the hypothalamus synthesize the hormones, and are transported down axons to the posterior pituitary where they are released into the blood

Which gland secretes melatonin which plays a role in the circadian rhythm?

pineal gland

What are the endocrine glands in the human brain?

1. hypothalamus,

2. pituitary gland

3. pineal gland

Which gland is located on the ventral surface of the trachea, just in front of the trachea?

thyroid

Thyroxine (T4) and triiodothyronine (T3) are lipid-soluble derivatives of which amino acid?

tyrosine

Which hormones are necessary for growth and neurological development in children, as well as increasing basal metabolic rate (BMR) in the body (negative feedback on TSH)?

thyroxine (T4) and triiodothyronine (T3)

Thyroxine (T4) and triiodothyronine (T3) contain which notable periodic element?

iodine

What is the condition where the thyroid under-secretes, resulting in low heart rate, low respiratory rate, and low BMR?

hypothyroidism

What is the condition where the thyroid over secretes, increasing BMR and sweating?

hyperthyroidism

(Note: both hypo and hyperthyroidism lead to goiter, or enlargement of thyroid gland)

Which hormone is a peptide hormone that 'tones down' Ca2+ in blood?

calcitonin

calcitonin stimulates the activity of what cell?

osteoblast, which builds up bone by using the calcium in the blood

What does calcitonin do to plasma Ca2+ concentrations?

decreases them

(Note: inhibiting its release from bone)

What is calcitonin's effect on osteoclasts?

decreases activity and number

Which is the only gland that produces more than one type of hormone?

thyroid

What are the four pea-shaped structures attached to the back of the thyroid?

parathyroid

Which hormone is antagonistic to calcitonin?

parathyroid hormone (PTH)

PTH does what to Ca2+ concentrations in the blood?

raises them

(Note: stimulating release from bone)

What is the effect of PTH on osteocytes?

1. increases osteocyte absorption of Ca2+ phosphate from bone

2. stimulates osteoclast proliferation

What is the effect of PTH on kidneys?

1. increase Ca2+ reabsorption

2. excrete renal phosphate

3. increase production of vitamin D derived steroid, which increases Ca2+ uptake from gut

What regulates parathyroid activity?

Ca2+ plasma concentration

(Note: parathyroid glands grow or shrink accordingly)

Which gland is involved in immune response, secretes thymosins that stimulate WBCs to become T cells that identify and destroy infected body cells?

thymus

Which gland rests on top of the kidneys?

adrenal gland

Which portion of the adrenal gland secretes only steroid hormones?

adrenal cortex (outer portion)

Which secretion of the adrenal cortex raises blood glucose levels, stimulating gluconeogenesis in the liver, and degrading adipose tissue to fatty acids for use as energy?

glucocorticoids (cortisol and

cortisone)

Which secretion of the adrenal cortex increases reabsorption of Na+ and excretion of K+ in kidneys?

Mineralocorticoids (aldosterone)

In what location does aldosterone act?

distal convoluted tubule and collecting duct of nephron

(Note: increase Na/Cl reabsorption and K+/H+ secretion)

What is the effect of aldosterone on blood pressure/volume?

increases both

(Note: results from net gain of particles drawing water in the nephron - has the same effect, but to a lesser extent, on sweat/ salivary glands and intestines)

Cortical sex hormones are secreted from which structure?

adrenal cortex

Which portion of the adrenal gland secrete fight or flight catecholamines?

adrenal medulla

The "fight or flight" response produced by the adrenal medulla is similar to which system's function?

sympathetic nervous system

(Note: adrenal medulla's effect lasts longer, considered stress hormones)

Epinephrine and norepinephrine cause the body to do what with glycogen?

convert to glucose

Epinephrine and norepinephrine are vasoconstrictors to which structures?

internal organs + skin

Epinephrine and norepinephrine are vasodilators to which structures?

skeletal muscle

Epinephrine and norepinephrine cause what effect on blood pressure and heart rate?

increase both

What is the effect of epinephrine and norepinephrine on metabolic activities

Increase metabolic activities (glycogenolysis, lipolysis)

What is the effect of epinephrine and norepinephrine on blood flow to the brain?

Increase blood flow to the brain

Which cells of the pancreas secrete glucagon which is catabolic, and released when energy is low, thus raising blood glucose levels

alpha cells

What effect does glucagon have on the liver?

1. convert glycogen to glucose

2. stimulate gluconeogenesis