10: Endocrine system

Question 1

What are the 4 basic ways of chemical communication of our body?

Answer 1

Autocrine, paracrine, neurotransmitter and endocrine

Question 2

What type of way of chemical communication releases signals that takes effect locally on the cell itself?

Answer 2

Autocrine

Question 3

What type of way of chemical communication releases signals that takes effect on other cell types without being transported in blood?

Answer 3

Paracrine

Question 4

What type of way of chemical communication produced by neurons, secreted into extracellular spaces by presynaptic nerve terminals and influences postsynaptic cells?

Answer 4

Neurotransmitter

Question 5

What type of way of chemical communication produces signals by cells of endocrine glands that enter the circulatory system and affect distance cells?

Answer 5

Endocrine

Question 6

What are the 3 characteristics of hormones?

Answer 6

• produced in small qty
• transport some dist. in circulatory system
• acts on target tissues elsewhere in body

Question 7

What are the 3 types of frequency of hormone secretion?

Answer 7

Acute, chronic, episodic

Question 7

10 functions of the endocrine system

Answer 7

1. Metabolism
2. Control of food intake and digestion
3. Tissue maturation
4. Ion regulation
5. Water balance
6. Heart rate and BP regulation
7. Control of blood glucose and other nutrients
8. control of reproductive functions (gametogenesis and pregnancy)
9. uterine contractions and milk release
10. immune system regulation

Question 8

What are the 10 endocrine glands of the body?

Answer 8

Pineal gland,
Hypothalamus,
Pituitary gland,
Thyroid gland,
parathyroid gland,
thymus gland,
adrenal glands,
pancreas,
ovary,
testes.

Question 9

What are the similarities between the nervous and endocrine systems?

Answer 9

• both associated with the brain (link between hypothalamus and pituitary gland)
• may use the same chemical messenger as neurotransmitter and hormones (e.g. epinephrine)
• both systems are cooperative (some parts of endocrine system innervated directly by nervous system such as the adrenal medulla)

Question 10

What are the differences between the nervous vs endocrine systems?

Answer 10

• mode of transport: axon vs blood
• speed of response” instant vs delayed, milliseconds vs seconds
• duration of response: milliseconds vs minutes, seconds vs days

Question 11

What is the other name of the posterior pituitary?

Answer 11

neurohypophysis

Question 12

What is the other name of the anterior pituitary?

Answer 12

adenohypophysis

Question 13

How are the posterior and anterior pituitary formed during gestation?

Answer 13

Posterior: downwards growth of the nervous tissue. Anterior: upwards growth of the oral cavity.

Question 14

What are the tissues that make up posterior vs anterior pitui?

Answer 14

Posterior: nervous. Anterior: glandular

Question 15

What are the types of hormones secreted by posterior vs anterior pitui?

Answer 15

Neuropeptides vs traditional hormones

Question 16

What is the relationship of the hypothalamus with the anterior pituitary?

Answer 16

It regulates the secretions of hormones from the anterior pituitary

Question 17

What is the relationship of the hypothalamus with the posterior pituitary?

Answer 17

Posterior pitui is an extension of the hypothalamus. Posterior pitui does not make hormones, but the hypothalamus produces neuropeptides that travels to posterior p. and get released from there. Posterior p. also stores the hormones.

Question 18

Where does the hormones passes through from hypothalamus to the posterior pitui? What is it made up of? What causes the hormone release?

Answer 18

Hypothalamohypophysial tract. Made of axons. Action potentials in these neurons causes the hormone release.

Question 19

Where does the hormones passes through from hypothalamus to the anterior pitui? What is it made up of? What causes the hormone release?

Answer 19

Hypothalamohypophysial portal system. Blood vessels. Hypothalamic releasing and inhibiting hormones stimulate or inhibit anterior pitui hormone release.

Question 20

What are the 8 hypothalamic hormones?

Answer 20

1. Growth hormone-releasing hormone (GHRH)
2. Growth hormone hormone-inhibiting hormone (GHIH).
3. Thyrotropin-releasing hormone (TRH)
4. Melanocyte releasing hormone (MRH)
5. Corticotropin-releasing hormone (CRH)
6. Gonadotropin-releasing hormone (GnRH)
7. Prolactin-releasing hormone (PRH)
8. Dopamine ( prolactin-inhibiting hormone, PIH).

Question 21

What are the 7 anterior pitui hormones?

Answer 21

1. Growth hormone (GH)
2. Thyroid stimulating hormone (TSH)
3. Adrenocorticotropic hormone (ACTH)
4. Melanocyte-stimulating hormone (MSH)
5. Luteinizing hormone (LH)
6. Follicle stimulating hormone (FSH)
7. Prolactin

Question 22

What kind of hormones stimulate the secretion of other hormones from target tissues?

Answer 22

Trophic hormones

Question 23

What hormones initiate an effect?

Answer 23

Non-trophic hormones

Question 24

In posterior pitui, _________________ of the neurons store neuro-hormones.

Answer 24

Axon terminals

Question 25

Action potential cause release of ______________ into the ____________ system (in the endocrine chapter)

Answer 25

neurohormones, circulatory system

Question 26

What are the 2 posterior pituitary hormones?

Answer 26

Antidiuretic hormones (ADH) and oxytocin

Question 27

What is a positive feedback example of hormones release?

Answer 27

Childbirth stretching of uterus and uterine cervix - increase APs in axons of oxytocin-secreting neurons - APs conducted by sensory neurons from the uterus and breast to spinal cord and up ascending tracts to the hypothalamus - APs conducted by axons of oxytocin-secreting neurons in the hypothalamohypophysial tract to the posterior pitui, where oxytocin secretion is increased - oxytocin enters the circulation and increase contractions of the uterus.

The cycle only stops when there’s a big change, e.g. baby got out from the uterus so there’s no longer a stretch in the uterus + uterine cervix.

Question 28

What is a negative feedback example of hormones release?

Answer 28

Hypothermia causes TRH (Thyroid releasing hormones) to be released from neurons from hypothalamus - then it passes through the hypothalamohypophysial portal system to the anterior pitui - then TRH causes secretion of TSH (thyroid stimulating hormones), which passes through the general circ to the thyroid - TSH causes increased synthesis and release of T3 and T4 into the general circ - T3 and T4 also inhibit the secretion of TRH from the hypothalamus and TSH from the anterior pituitary, while doing their jobs of increasing metabolism, body temp, normal growth and dev.

Question 29

Unique characteristics of thyroid gland?

Answer 29

Highly vascular, the only gland that stores hormone.

Question 30

What is the thyroid gland composed of?

Answer 30

follicles, follicular cells surrounding the thyroglobulin/thyroid hormones

Question 31

What 2 substances are necessary for the production of T3 and T4?

Answer 31

Iodine and tyrosine

Question 32

What are the functions of T3 and T4?

Answer 32

Increase rate of glucose, fat and protein metabolism in many tissues, thus increase body temp. Normal growth of many tissues.

Question 33

What are the full names of T3 and T4 (not compulsory to memorize)

Answer 33

Triiodothyronine, tetraiodothyronine/thyroxine.

Question 34

What is the full name of ACTHormone?

Answer 34

Adrenocorticotrophic hormone

Question 35

What causes the release of ACTH from anterior pituitary?

Answer 35

CRH (cortisol releasing hormones) from the hypothalamus

Question 36

What does ACTH do?

Answer 36

Causes cortisol (a glucocorticoid) secretion from the adrenal cortex + causes aldosterone (a mineralocorticoid) secretion from the adrenal cortex + causes secretion of androgen (a weak sex hormone)

Question 37

What’s the function of aldosterone?

Answer 37

Helps control sodium-water balance

Question 38

Which gland is triggered directly by the hypothalamus via the spinal cord + sympathetic nerve fiber to release hormones?

Answer 38

Adrenal medulla

Question 39

What hormones are secreted by the adrenal medulla triggered by the sympathetic nerve fiber?

Answer 39

Epinephrine and norepinephrine

Question 40

What are the other names of epinephrine and norepinephrine?

Answer 40

Adrenaline and noradrenaline

Question 41

What does MSH (melanocyte stimulating hormone) do?

Answer 41

acts on receptors in skin cells (melanocytes) and stimulates melanin (color pigment) in the skin. + role in regulating appetite and sexual behaviour.

Question 42

What hormones from the hypothalamus stimulates LH and FSH secretion?

Answer 42

GnRH (gonadotrophins releasing hormones)

Question 43

What are gonadotropins?

Answer 43

glycoprotein hormones that promote growth and function of the gonads

Question 44

What are the functions of LH and FSH in general? and in men vs women?

Answer 44

In general, regulate production of gametes and reproductive hormones.

In men: produced in testes - testosterone - for spermatogenesis and secondary sex characteristics

In women: produced in ovaries as estrogen and progesterone - for sex organ development and characteristics, menstrual cycle and pregnancy.

Question 45

What hormones are in charge for breast-feeding? Where are they secreted from?

Answer 45

Oxytocin for milk letdown, coming via posterior pitui; prolactin for milk production, coming from anterior pitui.

Question 46

Describe location of pancreas

Answer 46

near intestine and stomach, retroperitoneal

Question 47

What are the two types of glands in pancreas, what are their functions?

Answer 47

Exocrine gland that secretes into the ducts (produces pancreatic digestive juices into the duodenum to help with digestion) and endocrine gland that secretes into the blood (that consists of pancreatic islets)