A & P 2: Endocrine System

What do endocrine glands secrete?

hormones

What are the 6 things hormones can do?

alter gene expression, modify enzyme activity, influence growth and development, change membrane transport, alter metabolism, and increase or decrease secretion

What is the difference between the nervous and endocrine system?

nervous system = fast, electrical signals, precise targets, short duration

endocrine system = slow, chemical signals, widespread targets, long duration

hormone definition

signaling molecules that alter cell physiology

how do hormones travel?

through blood

why do only target cells respond to hormones?

receptors only bind to target cells

what do water soluble hormones do

cant cross membrane, bind to receptors on membrane, use second messengerwh

what do lipid soluble hormones do

diffuse through membrane, bind intracellular receptors, alter gene transcription

what is an example of a lipid soluble hormone

steroids

what is an example of a water soluble receptor

peptides

A hormone is released into the bloodstream, but a particular tissue

shows no response.

Which explanation is MOST likely?

A. The tissue lacks the appropriate receptor

B. Blood flow stopped completely

C. Hormones cannot circulate through plasma

D. The nervous system blocked the signal

A. The tissue lacks the appropriate receptor

what is the negative feedback loop

stimulus → hormone released → target responds → original disturbance reduced → hormone release decreases

give an example of a negative feedback loop involving blood glucose

blood glucose rises → insulin released → glucose decreases → insulin secretion decreases

what are the 6 things the hypothalamus monitors

osmolarity, circadian rhythms, blood chemistry, energy balance, stress, and temperature

the hypothalamus coordinates responses between which two systems

endocrine and nervous

what does the anterior pituitary do

produces hormones in response to hypothalamic signals

what does the posterior pituitary do

store and release hypothalamic hormones

what are the 2 hormones of the posterior pituitary

oxytocin and antidiuretic hormone (ADH)

what does ADH do

causes water retention in kidneys by decreasing urination and preventing dehydration

what does oxytocin do

attachment hormone, ejects milk, stimulates contractions

give an example of a positive feedback loop

cervical stretch → oxytocin release → stronger contractions → more cervical stretch → more oxytocin release

what are tropic hormones

hormones that act on another endocrine gland

what are direct hormones

act directly on tissues

list the tropic hormones

FSH, LH, TSH, ACTH

what are the direct hormones

GH, PRL

what is tsh

thyroid stimulating hormone

what is the target of tsh

thyroid gland

what is the result of tsh

thyroid gland releases T3 and T4

what is the ultimate effects of tsh

metabolism changes

what is acth

adrenocorticotropin hormone

what is the target gland of acth

adrenal cortex

what is the result of acth release

cortisol release

what is the ultimate effects of acth release

stress adaptation and glucose regulation

what is fsh

follicle stimulating hormone

what is LH

luteinizing hormone

what is the target gland of FSH/LH

gonads

what is the result of FSH/LH release

sex hormone production and gamete development

what is the ultimate outcome of FSH/LH relase

reproduction

what is GH

growth hormone

what is the target tissue of GH

many tissues (bone, liver, muscle)

what is the result of GH release

growth, protein synthesis, IGF-1 production

what is the ultimate outcome of GH release

growth and tissue development

what is PRL

prolactin

what is the target tissue for prolactin

mammary glands

what is the result of prl release

milk production

what is the ultimate outcome of PRL release

lactation and nourishment of infant

how does gigantism occur

excessive production of GH before plates ossify

how does acromegaly occur

excessive GH production after plates ossify, cartilage and connective tissue continue to grow

what are the anterior pituitary hormones

GH, FSH/LH, ACTH, PRL, TSH

what is the thyroid flow (hypothalamus → anterior pituitary → thyroid → effect)

TRH production → TSH release → T3 and T4 release → increased metabolic activity

where is the thyroid gland located

anterior to trachea

what cells synthesize thyroid hormones

follicular cells

what ion does the thyroid gland require

iodine

what are the 4 things the thyroid glands increases

metabolic rate, heat production, oxygen consumption, sympathetic nervous sensitivityw

what are the 3 things the thyroid gland supports

growth, development, nervous system maturation

what is myxedema

hypothyroidism or to little thyroid hormone production

what are symptoms of a patient with myxedema

fatigue, weight gain, cold intolerance, slowed thinking

what is graves disease

hyperthyroidism or overproduction of thyroid hormone

what are symptoms of graves disease

weight loss, tachycardia, hyperactiveness

what is goiter

enlarged thyroid gain commonly caused by iodine deficiency

how does goiter occur

low thyroid hormone → pituitary increases TSH → thyroid continuously stimulated → enlarged gland

A patient has:

 low T3/T4

 high TSH

Which structure is MOST likely dysfunctional?

A. Hypothalamus

B. Pituitary gland

C. Thyroid gland

D. Posterior pituitary

C. Thyroid gland

what is PTH

parathyroid hormone

what does PTH do

maintain blood calcium levels by increasing levels when low

what are the 5 things calcium is essential for

muscle contraction, neurotransmitter release, action potentials, cardiac function, clotting

where are the parathyroid glands

posterior to thyroid

what happens when blood calcium falls

low blood calcium → PTH released → osteoclasts stimulated → kidneys retain calcium → vitamin D activation increases → intestinal calcium reabsorption increases → blood calcium rises

what is osteitis cystica fibrosis

over secretion of PTH causes calcium to be stripped from bones and into blood

what are symptoms of osteitis cystica fibrosis

fragile bones, kidney stones, suppressed nervous system

what is hypoparathyroidism

to little production of PTH causing low blood calcium

symptoms of hypoparathyroidism

muscle twitches, convulsions, respiratory paralysis, death

A patient has severe hypocalcemia.

Why might muscle spasms occur?

A. Osteoclasts stop functioning

B. Thyroid hormone decreases

C. Cortisol increases directly

D. Calcium is required for normal neuromuscular function

D. Calcium is required for normal neuromuscular function

what does calcitonin do

decrease blood calcium levels by inhibiting osteoclast activity

what cells produce calcitonin

thyroid parafollicular (C) cells

A patient has:

 severe hypocalcemia

 muscle spasms

 tingling sensations

Which hormone would MOST likely increase?

A. Insulin

B. PTH

C. Calcitonin

D. Cortisol

B. PTH

what are the adrenal glands essential for

survival and stress adaptation

where are the adrenal glands located

superior to kidneys

what are the two major structures of the adrenal glands

adrenal cortex and the adrenal medulla

what is the function of the adrenal cortex

long term stress and regulation

what are the main hormones of the adrenal cortex

cortisol, aldosterone, and androgens

what does cortisol do

increase blood glucose, increase metabolism, support stress adaptation, decrease inflammation

what does aldosterone do

increase sodium reabsorption, increase water retention, increase potassium excretion

aldosterone regulates

fluid balance and blood pressure

cortisol regulates

stress and energy availability

what is cushings disease

increased cortisol

what are the symptoms of cushings disease

buffalo hump, moon face, muscle and bone loss, edema, hyperglycemia, high blood pressure

what is addisons disease

hyposecretion of adrenal cortex hormones

what are symptoms of addisons disease

weight loss, low blood pressure, fatigue, low tolerance to stress, dehydration, discoloration of skin and gums

what is adrenogenital syndrome

excessive androgen secretion

symptoms of adrenogenital syndrome

masculinized female newborn genital, beard development, enlarged children genitals, body masculinization

what is phenochromocytoma

tumor of adrenal medulla

symptoms of pheochromocytoma

hyperglycemia, tachycardia, hypertension, nervousness, hyperhidrosis

A patient has:

 low blood pressure

 dehydration

 low sodium levels

Which hormone would MOST likely increase?

A. Aldosterone

B. Calcitonin

C. Insulin

D. Prolactin

A. Aldosterone

what is the adrenal medulla known for

fight or flight response, close relation to sympathetic nervous system

what are the 2 hormones of the adrenal medulla

epinephrine and norepinephrine

what does epinephrine do

increase heart rate, blood pressure, breathing, alertness, blood glucose

what types of hormones do the adrenal parts produce

cortex: steroids medulla: catecholamines

what is the role of the pancrease

to maintain blood glucose levels

where are the endocrine cells of the pancreas

islets of langerhans

alpha cells produce

glucagon