Endocrine System Flashcards by Moeka Nakagawa

QUESTIONS

What are the 2 classes of glands? What do they produce? Which have ducts? Which are endocrine glands? (5) Which one is the neuroendocrine organ? Which have both endocrine and exocrine functions? (3)

Exocrine glands

Nonhormonal substances (sweat, saliva)
Have ducts to carry secretion to membrane surface

Endocrine glands

Produce hormones
Lack ducts
pituitary, thyroid, parathyroid, adrenal, and pineal glands

-Hypothalamus is neuroendocrine

Both = Pancreas, gonads, placenta

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What are the two types of hormones? Do they cross the plasma membrane? What do they act upon? How do they act at receptors? Which hormones are they?

Amino acid-based hormones

water soluble hormones. Do not cross phospholipid bilayer
Act on plasma membrane receptors
Act via G protein second messengers
all amino acid–based hormones except thyroid hormone

Steroids (Synthesized from cholesterol)

travel through membrane & into nucleus to affect protein synthesis
Act on intracellular receptors that directly activate genes
steroid and thyroid hormones
gonadal and adrenocortical hormones, not epi

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QUESTIONS

What are the three ways to stimulate hormone production? What feedback system do they regulate on to maintain what? How is each stimuli triggered? What is an example of each?

-Controlled by negative feedback systems to maintain homeostasis

Humoral stimuli

Changing blood levels of ions and nutrients
Declining blood Ca2+ concentration stimulates parathyroid glands to secrete PTH (parathyroid hormone) to increase blood Ca

Neural stimuli

Nerve fibers
Sympathetic nervous system fibers stimulate adrenal medulla to secrete epi & norepinephrine

Hormonal stimuli

Hormones stimulate other endocrine organs to release other hormones
Hormones from hypothalamus triggers Anterior pituitary gland that secretes hormones that stimulate other endocrine glands to secrete other hormones.

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QUESTIONS

Compare and contrast the differences between the ant and post lobe of the pituitary gland. What tissue is each made out of? Where do they originate? What kind of connections do they have? *What hormones do they secrete?

Anterior pituitary (lobe)

Glandular tissue
Originates as outpocketing of oral mucosa
Carries releasing and inhibiting hormones
makes GH and prolactin, LH, ACTH, FSH, TSH
anterior pituitary gland has the hypophyseal portal system

Posterior pituitary (lobe)

Neural tissue
Downgrowth of hypothalamic neural tissue
synthesize neurohormones oxytocin and antidiuretic hormone (ADH)
posterior pituitary gland has neurohypophysis

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QUESTIONS

How is the pituitary and the hypothalamus connected?

anterior: thru the hypothalamic-hypophyseal tract

- posterior: vascular connection to the hypothalamus

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QUESTIONS

What are the steps of the cAMP signaling mechanism? (6)

hormone (first messenger) binds to receptor
receptor turns on G protein
G protein activate adenylate cyclase
adenylate cyclase converts ATP to cAMP (2nd messenger)
cAMP activates protein kinases that phosphorylates proteins (which activates and inactivates)
cAMP degraded by phosphodiesterase

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QUESTIONS

What are the steps of the PIP2 calcium signaling mechanism after the G protein is activated?

*What splits PIP2 into DAG and IP3?

phospholipase C splits PIP2 into DAG and IP3
DAG activates protein kinase
IP3 causes Ca release (2nd messanger)
Ca alters enzyme activity & channels or binds to regulatory protein calmodulin
ca bound calmodulin activates enzymes that amplify cellular response

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The endocrine system acts with the ___ system to coordinate and integrate activity of body cells

nervous system

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Endocrine system Influences metabolic activities via ___ transported in blood

hormones

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endocrine response is slower/faster than nervous system?

slower

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What is Endocrinology

Study of hormones and endocrine organs

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What are the 5 functions of the endocrine system?

Reproduction
Growth and development
Maintenance of electrolyte, water, and nutrient balance of blood
Regulation of cellular metabolism and energy balance
Mobilization of body defenses

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Other tissues and organs that produce hormones (6)

Adipose cells, thymus, and cells in walls of small intestine, stomach, kidneys, and heart

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What are hormones? What do they travel in? (2)

long-distance chemical signals; travel in blood or lymph

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What is autocrines and paracrines? Are they part of the endocrine system? Why?

Autocrines: chemicals that affects same cells that secrete them

Paracrines: chemicals that affect cells other than those that secrete them

No - because they are local, not long-distance

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Steroids are produced by which 2 structures?

adrenal cortex & gonads

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What are target cells? How are they affected by hormones?

Tissues with receptors for specific hormone (reason why hormones circulate systemically but only cells with receptors for that hormone affected)
Hormones alter target cell activity

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What are the steps of the intracellular receptors & direct gene activation mechanism of steroids and thyroid hormones? (5)

*last step

Diffuse into target cells and bind with intracellular receptors
Receptor-hormone complex enters nucleus; binds to specific region of DNA
Prompts DNA transcription to produce mRNA
mRNA directs protein synthesis
Promote metabolic activities, or promote synthesis of structural proteins or proteins for export from cell

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What 3 factors does target cell activation depend on?

# receptors
type of hormone
3 affinity between receptor and hormone

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How do hormones influence number of their receptors? (2)

Up-regulation—target cells form more receptors in response to low hormone levels

Down-regulation—target cells lose receptors in response to high hormone levels

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True or false

Nervous system can override normal endocrine controls (Nervous system modifies stimulation of endocrine glands and their negative feedback mechanisms)

How is the hypothalamus related to this phemomenon?

true

-under severe stress, hypothalamus and sympathetic nervous system activated to increase body glucose levels rise

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Hormones circulate in blood either free or bound. Steroids and thyroid hormone are attached to ___. others circulate ___ carriers.

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plasma proteins

without

Concentration of circulating hormone reflects (2)

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Rate of release

Speed of inactivation and removal from body

Hormones removed from blood by ___ (3)

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Degrading enzymes
Kidneys
Liver

What is half life?

time required for hormone's blood level to decrease by half

Multiple hormones may act on same target at same time. What is permissiveness, synergism, antagonism?

Permissiveness: one hormone cannot exert its effects without another hormone being present Synergism: more than one hormone produces same effects on target cell  amplification Antagonism: one or more hormones oppose(s) action of another hormone

Hyperthyroidism and hypothyroidism. What is the metabolic rate for each one? Thyroxine levels? Heart rate? Temperature? *Unique characteristic of hyperthyroidism? How is hypothyroidism treated?

- hyperthyrodism = too much thyroxine = high metabolism - so usually thin, high HR, high BP, eyes bulge out of socket - hypothyrodism = too little thyroxine = slow metabolism - low HR, low temp - treat with synthroid, synthetic thyroxine

explain the renin-angiotensin-aldosterone mechanism What blocks this mechanism? This results in ___ blood pressure.

decreased blood pressure stimulates kidneys to release renin > triggers formation of angiotensin II, a potent stimulator of aldosterone release Atrial natriuretic peptide (ANP): blocks renin and aldosterone secretion to decrease blood pressure

What do glucocorticoids do? What hormone? *What is it released in response to? (3) What process does it promote? This increases the level of ___ (3) What happened in the old ages? Why should we look at the tummy of office workers? What do we eat when we are stressed?

- Keep blood glucose levels relatively constant - Cortisol (hydrocortisone) - Released in response to ACTH, patterns of eating and activity, and stress - gluconeogenesis: promotes rises in blood glucose, fatty acids, and amino acids in times of stress - when life was hard, food scarce. so when u stressed, body threw out cortisol so that when found, hold onto it - eating habits change, gain weight because of cortisol - when stressed, eat carbs/fats

What is Addison's disease? (2)

deficiency in glucocorticoids and mineralocorticoids

List the hormones released during short-term stress and describe the hormonal actions. What cells from what organ releases what hormone? does adrenaline increase? (3)* What happens to blood vessels? Where is blood diverted? (3)* What does hypersecreation and hyposecretion of adrenaline do?

- chromaffin cells from adrenal medulla release epinepherine & norepinephrine - Increased heart rate and metabolic rate, blood glucose levels - vasoconstriction - brain, heart, skeletal muscle - hypersecretion = hyperglycemia - hyposecretion = not a problem; Adrenal catecholamines not essential to life

***What hormone does the pineal gland secrete? Which cells? What does it affect? (4) Is it associated with ___ at night. This explains why we consume ___ food in the winter. Where are the receptors located? Why?

- Pinealocytes secrete melatonin - Day/night cycles, body temperature, sleep, appetite - Associated with drowsiness at night - consume more food in the winter rather than the summer - receptor in back of knee because that is where the sun ray shines

Pancreas has both ___ and ___ cells. Where do they travel? What body systems do they affect?

- exocrine & endocrine - exocrine travels thru ducts to go out - digestive system - endocrine travels inside the body - endocrine system

Which cells make glucagon and insulin? Is it a hypoglycemic or hyperglycemic hormone? What do they do? What does insulin enhance?

Alpha (α) cells produce glucagon (hyperglycemic hormone) Beta (β) cells produce insulin (hypoglycemic hormone) -insulin makes glycogen and stores it in the liver & SM -glucagon breaks down glycogen into glucose -enhances membrane transport of glucose into fat and muscle cells

What is type 1 and type 2 diabetes? Which one is due to hyposecretion? Hypoactivity? Around what age is each diagnosed? What causes type 2 diabetes?

- type 1 insulin dependent (injections) - autoimmune disease, own immune system attacks - diagnosed when young - type 2 not necessarily - receptors on body not functioning - due to insulin insensitivity caused by diet/PA - developed later in life (older patients)

What does osteocalcin prod? What body system is it associated with? What does it to fat storage? What does it do to glucose? Body fat?

- Skeleton (osteoblasts) | - Prods pancreas to secrete more insulin; restricts fat storage; improves glucose handling; reduces body fat

What structure in the skin is a precursor of vitamin D?

Cholecalciferol

What does the hypophyseal portal system include? (3) What does it carry?

Carries releasing and inhibiting hormones to anterior pituitary to regulate hormone secretion

What is ADH release triggered by? (3)

triggered by pain, low blood pressure, and drugs

Homeostatic Imbalances of Growth Hormone What does hypersecretion in children and adults result in? Hyposecretion in children?

Hypersecretion In children results in gigantism In adults results in acromegaly Hyposecretion In children results in pituitary dwarfism

Prolactin-inhibiting hormone is called ___.

dopamine

Describe the mechanism of thyroxine (T3/T4) production.

ER of follicular cells produce protein thyroglobulin and goes into the colloid-filled lumen. Iodide thru diet also goes into the lumen and become oxidized to form iodine. Iodine attaches to thyroglobulin to make T3/4 hormone/calcitonin. Then transported thru the follicular cells and undergoes endocytosis and into the capillary

Goiter goes away with ___ consumption.

iodine

Provide specific examples to demonstrate how the endocrine organs respond to maintain homeostasis in the body

Describe the three stages of the stress response (general adaptation syndrome).

1. stressors generate AP in the hypothalamus which activate the sympathetic nervous system 2. AP travel along the preganglionic sympathetic axons to the adrenal medulla 3. Adrenal medulla secrets epi/norepinephrine 4. epi/norepi activates the flight or fight system

the pituitary gland is also called the

hypophysis

Define tropic hormones. Which ones are they? (4)

- tropic so cause another gland to produce another hormone | - TSH, ACTH, FSH, and LH

this hormone is for flight or fight

epinephrine

Second-messenger mechanism depends on (2)

G proteins and cAMP

this gland is for immune response

thymus

Synthesis of more receptors on surface of cells when increased levels of hormone required is called

upregulation

is posterior pituitary an endocrine organ?

no, only a hormone storage area

what are the 2 mechanisms of water soluble hormones? what do they both involve?

cAMP, PIP2-calcium | both involves G proteins with second messangers (cAMP & Ca)

Endocrine System Flashcards

(53 cards)