Pp705 Lecture 4

Front 1

What is the function of hormones?

Back 1

Maintain homeostasis.

Front 2

What are the six types of chemical communication?

Back 2

1. Neurocrine (synaptic transmission)
2. Autocrine
3, Paracrine
4. Endocrine
5. Pheromones (but less in humans than animals)
6. Allomones (flowers and skunks)

Front 3

What are the first three of nine principles of hormonal action?

Back 3

1. Act gradually, over extended periods of time
2. Hormones alter intensity or probability of behaviors, not "all-or-none"
3. Quantities and types of hormones released depends on both external and internal factors, with reciprocal interaction between the two

Front 4

What are the second three (4-6) of nine principles of hormonal action?

Back 4

4. One hormone may affect multiple tissues and behaviors; one behavior or tissue site may respond to multiple hormones.
5. Hormones (with some exceptions) are usually produced in small amounts and released in "bursts" (pulsatile action)
6. Levels of hormones may vary rhythmically, controlled by internal "clocks"

Front 5

What are the last three (7-9) of nine principles of hormonal action?

Back 5

7. Hormones interact
8. Hormones are similar in structure across species, but not necessarily in function.
9. Hormones can only affect structures with the right receptor protein.

Front 6

In comparing neurotransmission to hormonal effects, what are the four main differences?

Back 6

1. Hormones are "broadcast" and affect many parts of body that may be distant from sources.
2. Hormone messages last seconds to minutes or even hours, not milliseconds.
3. Hormone messages are usually analog rather than "all-or-none"(digitized) like neural transmission.
4. Much harder to voluntarily control or change hormonal messages.

Front 7

In comparing neurotransmission to hormonal effects, what are the three main similarities?

Back 7

1. Hormones are stored to await secretion similar to neurotransmitters in vesicles.
2. Second messenger systems are common to both, and are often the same second messengers (e.g., cAMP and cGDP)
3. There must be a specific receptor present to respond to a hormone

Front 8

What is the bridge between neurotransmission and hormonal systems

Back 8

neuroendocrine cells: an arriving action potential , from ordinary neuron, triggers release of hormone instead of a new action potential

Front 9

What are the three types of hormones?

Back 9

Protein, amine, and steriod

Front 10

What are the main characteristics of protein and amine hormones?

Back 10

Strings of amino acids, Short strings get called peptide hormones, and may often act as neuromodulators (cotransmitters), i.e., they alter reactivity of cells to other transmitters or hormones.
1. Bind to surface receptors
2. Second messenger system that changes proteins that are already present inside the cell. Examples: cAMP, cGMP, phosphoinosotides.
3. Relatively rapid action: seconds to minutes

Front 11

What are the main characteristics of steroid hormones?

Back 11

Steroid hormones—four interconnected rings with various molecules attached
1. Pass through cell membrane and bind to receptors inside the cell; if no receptor, the steroid just goes right through. Must also have receptor cofactors for cell to respond.
2. Receptor-protein complex passes into nucleus and binds to DNA, which affects the production of new proteins. Cofactors determine which genes get activated
3. Generally much slower, longer-lasting effect compared to other hormones: hours to days or longer
4. Also a nongenomic effect, from receptors in membrane, in some cases IV.

Front 12

How are hormones regulated?

Back 12

Most hormones are regulated via negative feedback loops.

Front 13

What different types of hormonal feedback loops exist?

Back 13

1. Autocrine
2. From target cell
3. To the brain and/or the secreting gland
4, More complex involving the hypothalamus and pituitary

Front 14

What is the function of the posterior pituitary?

Back 14

Contains axons of neuroendocrine glands that originate in the hypothalamus and releases them directly in the bloodstream.

Front 15

What hormones does the posterior pituitary produce?

Back 15

Oxytocin and Vasopressin

Front 16

What are the two common abbreviations for Vasopressin?

Back 16

ADH (Anti-diuretic hormone) &
AVP (arginine vasopressin)

Front 17

What is the function of the Anterior Pituitary?

Back 17

It contains cells that produce tropic hormones that are stimulated to release (or inhibit release) by "releasing hormone" from the hypothalamus

Front 18

What are the seven main releasing hormones?

Back 18

thyrotropic¬releasing hormone (TRH)
corticotropic-releasing hormone (CRH):
gonadatropic-releasing hormone (GnRH)
somatocrinin
somatostatin
prolactin-releasing peptide
prolactin-inhibiting factor (dopamine?)

Front 19

What are the six main tropic hormones?

Back 19

Thyroid-stimulating hormone (TSH)
Adrenocorticotropic hormone (ACTH)
Leuteinizing hormone (LH); Follicle-stimulating hormone (FSH)
Growth hormone (Gil)
Prolactin

Front 20

What does ACTH do?

Back 20

controls production and release of steroid hormones in adrenal cortex

Front 21

What does TSH do?

Back 21

stimulates release of thyroid hormones, which are stored in large quantities

Front 22

What does LH do?

Back 22

stimulates release of egg from ovary or production or testosterone

Front 23

What does FSH do?

Back 23

stimulates secretion of estrogen or testosterone

Front 24

What does prolactin do?

Back 24

stimulates development of lactation

Front 25

What does GH do?

Back 25

influences growth of cells and tissue, but released only during early stage sleep

Front 26

What process do the Anterior Pituitary hormones follow?

Back 26

Hypothalamus sends releasing hormone into portal blood veins that take it into pituitary, which then release the tropic hormones into the main blood system
*portal veins therefore do not share blood-brain barrier with rest of the brain circulatory system
*feedback information comes through the portal system

Front 27

What is the target of ACTH and what hormone does that gland produce?

Back 27

The adrenal cortex (outside)

The adrenal cortex produces: a. glucocorticoids (cortisol)
b. mineralocorticoids (aldosterone)
c. sex steroids (androstenedione)

Front 28

What is the target of TSH and what hormone does that gland produce?

Back 28

The thyroid

The thyroid produces:
Thyroid hormones

Front 29

What are the targets of LH & FSH and what hormones do those glands produce?

Back 29

The testes and the ovaries.

The testes and the ovaries produce testosterone (androgens), estrogens, and progestins

Front 30

What does the adrenal medulla produce?

What part of the nervous system does it belong to?

Back 30

epinephrine and norepinephrine

part of sympathetic nervous system

Front 31

How are thyroid hormones different than most amine hormones?

Back 31

They act like steroids and bind DNA to regulate gene expression

Front 32

Do gonadal tropic hormones have more complex effects in males or females?

Back 32

Females

Front 33

What are sex hormones derived from?

Back 33

cholesterol

Front 34

What type of hormone do all sex hormones start out as?

Back 34

progestins

Front 35

What does the pineal gland secrete?

Back 35

Melatonin

Front 36

What does melatonin do?

Back 36

Melatonin affects sleep, and also sensitivity of hypothalamus to negative feedback from gonadal steroids.

Front 37

What is hypovolemic thirst caused by?

Back 37

General loss of body fluids, without changes in sodium concentration inside or outside cells

Front 38

What is osmotic thirst caused by?

Back 38

Sudden increase in extracellular solute (e.g., NaCl) from a salty meal

Front 39

What is the initial sequence of events in hypovolemic thirst?

Back 39

a. Baroceptors in kidneys inform brain of fluid loss
b. Hypothalamus releases vasopressin (ADH), when reduces flow of water out of kidneys
c. Kidneys release renin into blood, which converts angiotensinogen into
angiotensin I, which then converted in angiotensin II

Front 40

What effects does angiotensin II have on the body (hypovolemic thirst)?

Back 40

a. Constriction of blood vessels
b. circumventricular organs (especially the subfornical organ) trigger drinking
c. ADH is released
d. Alsosterone is released

Front 41

Explain the relationship between Glucagon and Insulin

Back 41

Glucagon is released in response to low blood sugar, and causes liver to convert glycogen into glucose and thus increase glucose levels: direct negative feedback.
Insulin released in response to rising blood sugar, and causes increased uptake of glucose and reduced output of glucose by liver, so glucose levels fall

Front 42

What are examples of protein hormones?

Back 42

ACTH, FSH, LH, TSH, GH, prolactin, insulin, glucagon, oxytocin, AVP, CRH, GnRH, etc.

Front 43

What are examples of amine hormones?

Back 43

epinephrine
norepinephrine
thyroid
melatonin

Front 44

What are examples of steroid hormones?

Back 44

Estrogens
Progestins
Androgens (testosterone)
Glucocorticoids (cortisol)
Mineralcorticoids (aldosterone)

Front 45

What two specific regions of the hypothalamus create hormones?

Back 45

supraoptic nucleus
paraventricular nucleus

Front 46

What is the name of the blood system which the neuroendicrine cells release releasing hormones?

Back 46

The portal system, also known as the hypophyseal.

Front 47

What does cortisol do?

Back 47

increases the level of blood glucose and accelerates breakdown of proteins

Front 48

What does aldosterone do?

Back 48

Acts on kidneys to retain sodium and reduce urine production

Front 49

What are the hormone secreting cells of the pancreas called?

Back 49

Islets of Langerhans